Yellowfin tuna

Yellowfin tuna is assumed to be a single stock across Indian Ocean. This is supported by the tag recoveries that provide evidence of large movements of yellowfin tuna. However, some more detailed analysis of fisheries data suggests that the stock structure may be more complex. A study of stock structure using DNA was unable to detect whether there were subpopulations of yellowfin tuna in the Indian Ocean (IOTC 2008a).

At regional level (Indian Ocean), a range of assessments were presented in the Meeting of the Working Party on Tropical Tunas (WPTT) in Bangkok, 23 to 31 November, 2008, which included Multifan-CL, a Stock Synthesis 2 (SS2) model and an Age-structured Production Model (ASPM). Multifan – CL is a size-based, age- and spatially-structured population model that has the functionality to integrate the tagging data obtained from the Indian Ocean Tagging Programme. Stock Synthesis 2 (SS2) model used catch-at-length data, growth and a CPUE series to model the stock dynamics while ASPM used catch-at-age data and a CPUE series to estimate biomass trends and management-related parameters. Most of the models appear to provide similar perspectives on the status of the stocks despite their different levels of complexity and the uncertainties. In overall, all assessment results indicated that the biomass is below the MSY-based level and that the catch and harvest rates are slightly above MSY levels (IOTC 2008b).

At Indonesia level, several workshops have been conducted as attempts to assess the stock size of tuna in Indonesian waters. However, up until now, due to lack of accurate statistical data (that meet data requirements for scientific stock assessments), there is no scientific stock assessments relating to tunas and tuna-like species in Indonesia. Therefore tuna experts then came into agreement that until this point, there is no one that can estimate the reasonable stock size of Indonesian tuna. The tuna experts then agreed that the most important thing to assess the stock size of Indonesian tuna fisheries is by studying indicators to predict the condition and status of Indonesian tuna fisheries rather than trying to estimate the Indonesian tuna stock size.

Yellowfin tuna is assumed to be a single stock across Indian Ocean. This is supported by the tag recoveries that provide evidence of large movements of yellowfin tuna. However, some more detailed analysis of fisheries data suggests that the stock structure may be more complex. A study of stock structure using DNA was unable to detect whether there were subpopulations of yellowfin tuna in the Indian Ocean (IOTC 2008a).

At regional level (Indian Ocean), a range of assessments were presented in the Meeting of the Working Party on Tropical Tunas (WPTT) in Bangkok, 23 to 31 November, 2008, which included Multifan-CL, a Stock Synthesis 2 (SS2) model and an Age-structured Production Model (ASPM). Multifan – CL is a size-based, age- and spatially-structured population model that has the functionality to integrate the tagging data obtained from the Indian Ocean Tagging Programme. Stock Synthesis 2 (SS2) model used catch-at-length data, growth and a CPUE series to model the stock dynamics while ASPM used catch-at-age data and a CPUE series to estimate biomass trends and management-related parameters. Most of the models appear to provide similar perspectives on the status of the stocks despite their different levels of complexity and the uncertainties. In overall, all assessment results indicated that the biomass is below the MSY-based level and that the catch and harvest rates are slightly above MSY levels (IOTC 2008b).

At Indonesia level, several workshops have been conducted as attempts to assess the stock size of tuna in Indonesian waters. However, up until now, due to lack of accurate statistical data (that meet data requirements for scientific stock assessments), there is no scientific stock assessments relating to tunas and tuna-like species in Indonesia. Therefore tuna experts then came into agreement that until this point, there is no one that can estimate the reasonable stock size of Indonesian tuna. The tuna experts then agreed that the most important thing to assess the stock size of Indonesian tuna fisheries is by studying indicators to predict the condition and status of Indonesian tuna fisheries rather than trying to estimate the Indonesian tuna stock size.

Yellowfin tuna is assumed to be a single stock across Indian Ocean. This is supported by the tag recoveries that provide evidence of large movements of yellowfin tuna. However, some more detailed analysis of fisheries data suggests that the stock structure may be more complex. A study of stock structure using DNA was unable to detect whether there were subpopulations of yellowfin tuna in the Indian Ocean (IOTC 2008a).

At regional level (Indian Ocean), a range of assessments were presented in the Meeting of the Working Party on Tropical Tunas (WPTT) in Bangkok, 23 to 31 November, 2008, which included Multifan-CL, a Stock Synthesis 2 (SS2) model and an Age-structured Production Model (ASPM). Multifan – CL is a size-based, age- and spatially-structured population model that has the functionality to integrate the tagging data obtained from the Indian Ocean Tagging Programme. Stock Synthesis 2 (SS2) model used catch-at-length data, growth and a CPUE series to model the stock dynamics while ASPM used catch-at-age data and a CPUE series to estimate biomass trends and management-related parameters. Most of the models appear to provide similar perspectives on the status of the stocks despite their different levels of complexity and the uncertainties. In overall, all assessment results indicated that the biomass is below the MSY-based level and that the catch and harvest rates are slightly above MSY levels (IOTC 2008b).

At Indonesia level, several workshops have been conducted as attempts to assess the stock size of tuna in Indonesian waters. However, up until now, due to lack of accurate statistical data (that meet data requirements for scientific stock assessments), there is no scientific stock assessments relating to tunas and tuna-like species in Indonesia. Therefore tuna experts then came into agreement that until this point, there is no one that can estimate the reasonable stock size of Indonesian tuna. The tuna experts then agreed that the most important thing to assess the stock size of Indonesian tuna fisheries is by studying indicators to predict the condition and status of Indonesian tuna fisheries rather than trying to estimate the Indonesian tuna stock size.

Yellowfin tuna is assumed to be a single stock across Indian Ocean. This is supported by the tag recoveries that provide evidence of large movements of yellowfin tuna. However, some more detailed analysis of fisheries data suggests that the stock structure may be more complex. A study of stock structure using DNA was unable to detect whether there were subpopulations of yellowfin tuna in the Indian Ocean (IOTC 2008a).

A range of assessments were presented in the Meeting of the Working Party on Tropical Tunas (WPTT) in Bangkok, 23 to 31 November, 2008, which included Multifan-CL, a Stock Synthesis 2 (SS2) model and an Age-structured Production Model (ASPM).Multifan – CL is a size-based, age- and spatially-structured population model that has the functionality to integrate the tagging data obtained from the Indian Ocean Tagging Programme. Stock Synthesis 2 (SS2) model used catch-at-length data, growth and a CPUE series to model the stock dynamics while ASPM used catch-at-age data and a CPUE series to estimate biomass trends and management-related parameters. Most of the models appear to provide similar perspectives on the status of the stocks despite their different levels of complexity and the uncertainties. In overall, all assessment results indicated that the biomass is below the MSY-based level and that the catch and harvest rates are slightly above MSY levels (IOTC 2008b).

Although important progress in the quality and quantity of analyses conducted, there remain uncertainties in the application of the models that prevented the SC from determining the current status of yellowfin tuna in a precise way. Nevertheless, most of the analyses conducted coincide in indicating that the stock is very close to an overfished state, or already overfished, and that the exploitation rate in recent years has exceeded the optimal level (2008a).

Last updated on 05 Mar 2013

According to Indonesian national statistics, the annual estimated catch of yellowfin tuna in 2011 was 38,550t. Yellowfin tuna contributes more than 29% of total tuna catch; the highest percentage is skipjack with more than 47% of the annual catch in 2011. The annual yellowfin tuna catch using longline continues to show decreases since 2005 (2005: 47,570 t; 2006: 27,090t; 2007: 15,837t; 2008: 15,133t; 2009: 13,487t; 2010:14,572t; and 2011: 8976t) (IOTC, 2012b).

Three main landing sites for the Indian Ocean tuna longline vessels are Benoa (Bali), Muara Baru (north Jakarta) and Cilacap (Central Java) fishing ports (Proctor et al., 2003). Benoa fishing port contributes more than 60% of tuna catch where the dominant catch is yellowfin tuna (IOTC., 2011). The estimated of annual catch of yellowfin tuna reported from Benoa has also shown a decrease since 2009, where the catch was 7,240t in 2009, was 5372t in 2010 and was 3008 tonnes in 2011.

The number of Indonesian registered tuna fishing vessels operated in IOTC in 2012 is 1,278 and consists of 1,256 longline, 19 purse seine, 2 gillnet, and 1 carrier boat (IOTC, 2012b).

Yellowfin biomass has been substantially declining since, at least, the mid-1980s. Since the early 1980s, there has been a continuous increase in F. The stock assessments, including independent analyses of the tagging data, indicate that recruitment has declined in recent years (IOTC, 2008b). Estimates of total and spawning stock biomass show a marked decrease over the last decade, accelerated in recent years by the high catches of 2003-2006. It appears that the stock is currently overfished or approaching an overfished state, and overfishing has probably been occurring over recent years. The effect on the standing stock of the high catches of the 2003-2006 period is still noticeable as biomass appears to be decreasing despite catches returning to pre-2003 levels (IOCT, 2010c).

In terms of the internstionl fishery, purse seiners currently take the bulk of the yellowfin catch, mostly from the western Indian Ocean around the Seychelles (IOTC, 2008b). Contrary to the situation in other oceans, the artisanal fishery component in the Indian Ocean is substantial, taking approximately 37% of the total catch in weight (IOTC, 2010c). Artisanal catches, taken by bait boat, gillnet, troll, hand line and other gears have increased steadily since the 1980s. In recent years the total artisanal yellowfin catch has been around 130,000-140,000 tonnes, with the catch by gillnets (the dominant artisanal gear) at around 80,000 tonnes to 90,000 tonnes (IOTC, 2010c).

Since 1993, mean weights in the catches in the industrial fisheries have declined. Prior to 2003, although total catch in biomass has been stable for several years, catches in numbers have continued to increase, as there has been more fishing effort directed towards smaller fish. While there is a large amount of uncertainty about likely future catches, recent events in 2008 where some vessels have left the fishery, together with fleets avoiding the historically important fishing grounds in the waters adjacent to Somalia for security reasons, may reduce catches in the short-term to below the pre-2003 levels (IOTC, 2008c, 2010c).

Last updated on 19 Apr 2010

At national level, total yellowfin tuna landings in Indonesia shows downward trend after peaked in 2000 with 163,241 tonnes. In 2006, total yellowfin tuna production reached its lowest point with 94,406 tonnes. Catch data from Fishery Management Region IX (Indian Ocean, and Bali Strait) also decreased from 56,146 tonnes in 2000 to 42,862 tonnes in 2004. This area contributed to almost 54% of total yellowfin catches in Indonesia in 2004. See: Distribution of yellowfin tuna landings in Indonesia

Although tuna production increased in parallel with the increase of number of fishing vessels, in Benoa, Bali (Eastern Indian Ocean), total catch per fishing day has been decreasing with average of 4.7% per year. In 1992, Catch per Unit Effort (CPUE) was 406 (kg/one fishing day) and in 2000, it declined to 177 (kg/one fishing day).

Data from Benoa-Bali (Indian Ocean) also noted that along with the increase of number of fishing vessels operating in Indian Ocean, the hook rates have continued to decrease. In the beginning of tuna fisheries in Benoa in 1970s, the average hook rate was between 1.15 and 2.16 fishes per 100 baits, before kept declining to 0.60 in 2000. However, in 2001 and 2002 the hook rate increased slightly to 0.70 and 0.74 respectively (Merta et al., 2003).

Last updated on 19 Apr 2010

At national level, total yellowfin tuna landings in Indonesia shows downward trend after peaked in 2000 with 163,241 tonnes. In 2006, total yellowfin tuna production reached its lowest point with 94,406 tonnes. Catch data from Fishery Management Region IX (Indian Ocean, and Bali Strait) also decreased from 56,146 tonnes in 2000 to 42,862 tonnes in 2004. This area contributed to almost 54% of total yellowfin catches in Indonesia in 2004. See: Distribution of yellowfin tuna landings in Indonesia

Although tuna production increased in parallel with the increase of number of fishing vessels, in Benoa, Bali (Eastern Indian Ocean), total catch per fishing day has been decreasing with average of 4.7% per year. In 1992, Catch per Unit Effort (CPUE) was 406 (kg/one fishing day) and in 2000, it declined to 177 (kg/one fishing day).

Data from Benoa-Bali (Indian Ocean) also noted that along with the increase of number of fishing vessels operating in Indian Ocean, the hook rates have continued to decrease. In the beginning of tuna fisheries in Benoa in 1970s, the average hook rate was between 1.15 and 2.16 fishes per 100 baits, before kept declining to 0.60 in 2000. However, in 2001 and 2002 the hook rate increased slightly to 0.70 and 0.74 respectively (Merta et al., 2003).

Last updated on 28 Mar 2012

According to official data from FAO, total catch of yellowfin tuna from Sri Lanka in 2007 was 40,397 tonnes, making this country the biggest yellowfin tuna producer in Indian Ocean, contributing to 13.35% of total yellowfin tuna landing in this ocean, followed by Spain (12.53%). Yellowfin tuna contributes more than 34% of total tuna catch in the country; the biggest one is skipjack with more than 50% of total tuna landing. Yellowfin tuna catch in Sri Lanka has shown the upward trend, though the production dropped significantly once in 2005, where the catch dropped by 30% from 35,512 tonnes to 24,887 tonnes due to the tsunami which was hit the country in December 2004.The 2004 Tsunami caused damage to one third of marine fishing fleet in Sri Lanka. Subsequent reconstruction funds have increased the fishing capacity to pre-tsunami level or far above the pre-2004 level.

According to the latest data from Department of Fisheries and Aquatic Resources (2009), yellowfin tuna landing in 2008 reached 47,590 tonnes. The main landing sites of yellowfin tuna are Matara (31.1%), Trincomalee (21.3%), Kalutara (14.1%), Negombo (10.6%) and Tangalle (7.9%) – See the Map of Districts in Sri Lanka .

Small scale gillnets and tuna long lines are the two main fishing methods used by Sri Lankan fishermen to target for tuna and tuna like fishes. There are over 3,000 boats are now engaged in tuna fisheries in Sri Lanka, with about 1,700 operating in offshore areas (IOTC 2007).“Multiday” operations are more frequent, producing a corresponding increase in effort. The average catch rate of the fleet operating in coastal waters is about 100 kg/fishing day, whereas in offshore waters, it ranges from 250 to 435 kg/ fishing day. Tunas and tuna-like species constitute 50 % of the total large pelagic catch in Sri Lanka (IOTC 1998).

Eventhough the main fishing gear is gill netting more than 40% of the fleet carry long lines specially during non-monsoon seasons. Other than this Sri Lanka owns 8 small sized (52ft) fresh tuna longliners targeted for yellowfin and bigeye. These boats operate throughout the year in EEZ of Sri Lanka and high seas. It is estimated that a further 26,000 tonnes of medium sized yellowfin and other tuna are landed by coastal tuna longline fishery operated with 20-40 km distance from the shore especially in the north west and northeast coasts of Sri Lanka. The fishery is conducted by 5-6 m long outboard engine day-boats. The reported species composition was dominated by 65% of yellowfin tuna (IOTC 2007).

With the issue of permits to fishing companies to land the tuna catch of longliners operated in international waters, a few local boat owners have started conducting tuna longlining at 50-100m depths, targeting on large, deep swimming yellowfin and bigeye tuna. Recently, a resource survey using longlining has been commenced.

Last updated on 22 Jun 2012

Fishing effort from Thai longliners was relatively low in Indian Ocean. 3 longliners operated in the Western Indian Ocean (the area around the south and east coast of Madagascar) in 2007, with only two were operating in subsequent years. Albacore formed the dominant catch, followed by yellowfin tuna and bigeye tuna (Saikliang and Nootmorn 2011).Thai vessels fished in four zones in the Indian Ocean namely, Bay of Bengal, West coast of Indonesia, Seychelles and Somalia (IOTC 2008d). A detailed account of tuna longlining by Thai vessels in the Indian Ocean is available in Nootmorn et al., (2010).

The biomass has been substantially declining since, at least, the mid-1980s. Since the early 1980s, there has been a continuous increase in F. The stock assessments, including independent analyses of the tagging data, indicate that recruitment has declined in recent years (IOTC, 2008b). Estimates of total and spawning stock biomass show a marked decrease over the last decade, accelerated in recent years by the high catches of 2003-2006. It appears that the stock is currently overfished or approaching an overfished state, and overfishing has probably been occurring over recent years. The effect on the standing stock of the high catches of the 2003-2006 period is still noticeable as biomass appears to be decreasing despite catches returning to pre-2003 levels (IOTC, 2010c).

Since 1993, mean weights in the catches in the industrial fisheries have declined. Prior to 2003, although total catch in biomass has been stable for several years, catches in numbers have continued to increase, as there has been more fishing effort directed towards smaller fish. While there is a large amount of uncertainty about likely future catches, recent events in 2008 where some vessels have left the fishery, together with fleets avoiding the historically important fishing grounds in the waters adjacent to Somalia for security reasons, may reduce catches in the short-term to below the pre-2003 levels (IOTC, 2008c, 2010c).

Indonesian seas are divided into eleven Fisheries Managament Areas (FMAs), of which two FMAs, covering the seas on the west of Sumatera, south of Java until south of east Nusa Tenggara are located within the Indian Ocean Tuna Commission area. Indonesia has a total of 5,8 million km2 of marine waters; the Exclusive Economic Zone (12 – 200 miles) covers an area of 2,7 million km2 and 2,7 million km2 is territorial waters (<12 miles).

The Indonesian tuna fisheries are comprised of artisanal/traditional and small-scale fisheries. The artisanal/traditional fisheries are characterized by the use of small non-motorized and motorized boats with small outboard or inboard engines. The sizes of the boats range from 10 to 15 meters in length. The vessels’ capacity is roughly between less than 10 GT and up to 30 GT. The small scale fisheries comprise vessels greater than 30 GT of greater than 24 meters length. The main tuna species caught are yellowfin, bigeye, albacore and skipjack.

Indonesia has created a National Plan of Action for the management of tuna and there is a draft National Tuna Management Plan. The plan includes ways to improve monitoring, identifying catch limits, and aiding in enforcement and compliance measures {MMAF 2012}{MMAF 2014a}. Indonesia also has a National Plan of Action, tuna skipjack and neritic tuna in place {MMAF 2014b}. Indonesia is also a member of the Indian Ocean Tuna Commission.

No catch limits are in place for yellowfin tuna in the Indian Ocean. A proposal for adopting a catch limit for yellowfin tuna was introduced in 2009, along with proposed TACs for bigeye tuna and swordfish. The proposal was to introduce catch restrictions on yellowfin tuna (to the levels recommended by the Scientific Committee), including catch allocations for Members (on the basis of the catch figures indicated in the IOTC Scientific Committee report 2008). These proposals were submitted in response to the advice from the Scientific Committee that yellowfin tuna stocks were evaluated to be at levels near or below MSY; and recognizing the importance of applying the precautionary approach for the management of the stock in the Indian Ocean. However, after considerable debate, no consensus was reached on a formula to distribute the allowable catches between Members, and the proposals for catch limits were dropped from further consideration at the 2009 IOTC meeting.

The Indian Ocean Tuna Commission (IOTC) is one of five global tuna-regional fisheries management organizations. IOTC is mandated to manage tuna and tuna-like species in the Indian Ocean and adjacent seas. Its objective is to promote cooperation among its Members with a view to ensuring, through appropriate management, the conservation and optimum utilization of stocks and encouraging sustainable development of fisheries based on such stocks. Members of IOTC are Australia, Belize, China, Comoros, Eritrea, European Community, France, Guinea, India, Indonesia, Republic Islamic of Iran, Japan, Kenya, Republic of Korea, Madagascar, Malaysia, Mauritius, Sultanate of Oman, Pakistan, Philippines, Seychelles, Sierra Leone, Sri Lanka, Sudan, Tanzania, Thailand, United Kingdom, and Vanuatu. The Cooperating Non-Contracting Parties are Senegal, South Africa and Uruguay.

In regards to Indonesian capture fisheries policy, management target of capture fisheries is defined by MSY. Management target for capture fisheries is set at level of 80% of MSY (MMAF, 2005).

Management of the tuna fisheries, as in other fisheries in Indonesia, is mainly by input controls through licensing, implementation of log book system, installment of a vessel monitoring system, and institutional strengthening. License is granted on the basis of fish stock utilization status, and a new license will not be issued when fish stock is fully or over exploited. Fishing fee is charged on the basis of resource rent. Tuna fishery protection also covered through regulation and limitation on the fishing fleets, fishing ground and fish landing. However, direct impact of protection still not found in the ground level.

There is no officially set TAC. In regards to Indonesian capture fisheries policy, management target of capture fisheries is defined by MSY. Management target for capture fisheries is set at level of 80% of MSY (MMAF, 2005).Using 1997, then MSY of yellowfin tuna in Indonesia’s waters of Indian Ocean is 33,020 tonnes. In the regional fisheries management, in 2007, Indonesia has just achieved of Full Member status of both Indian Ocean Tuna Commission (IOTC).

Currently, there is also no catch limits decided for yellowfin tuna in Indian Ocean. The proposal for catch limits for yellowfin tuna was put forward in the IOTC Meeting in 2009 together with bigeye and swordfish. The proposals was to introduce catch restrictions on yellowfin tuna (to the levels recommended by the Scientific Committee), including catch allocations for Members (on the basis of the catch figures indicated in the IOTC Scientific Committee report 2008). These proposals were submitted in response to the advice from the Scientific Committee that yellowfin tuna stocks are evaluated to be at levels near or below MSY; and recognizing the importance of applying the precautionary approach for the management of the stock in the Indian Ocean. However, after considerable debate, no consensus was reached on a formula to distribute the allowable catches between Members, and the proposals for catch limits were dropped from further consideration at this Session. The Chair encouraged Members interested in proposing similar measures to engage in consultations well in advance of the next Session, so as to increase the chances of adoption (IOTC, 2009a). In total, there are 3,363 vessels under Authorized Fishing Vessels as per 03 February 2009. Indonesia contributes the biggest portion of these vessels, contributing to 26% of them or about 874 vessels, followed by Iran (22.7%), European countries (14.6%), Japan (12.2%) and Republic of Korea (5.5%) (IOTC, 2009b).

Management of the tuna fisheries, as in other fisheries in Indonesia, is mainly by input controls through licensing, implementation of log book system, installment of a vessel monitoring system, and institutional strengthening. License is granted on the basis of fish stock utilization status, and a new license will not be issued when fish stock is fully or over exploited. Fishing fee is charged on the basis of resource rent. Tuna fishery protection also covered through regulation and limitation on the fishing fleets, fishing ground and fish landing. However, direct impact of protection still not found in the ground level.

There is no officially set TAC. In regards to Indonesian capture fisheries policy, management target of capture fisheries is defined by MSY. Management target for capture fisheries is set at level of 80% of MSY (MMAF, 2005).Using 1997, then MSY of yellowfin tuna in Indonesia’s waters of Indian Ocean is 33,020 tonnes. In the regional fisheries management, in 2007, Indonesia has just achieved of Full Member status of both Indian Ocean Tuna Commission (IOTC).

Currently, there is also no catch limits decided for yellowfin tuna in Indian Ocean. The proposal for catch limits for yellowfin tuna was put forward in the IOTC Meeting in 2009 together with bigeye and swordfish. The proposals was to introduce catch restrictions on yellowfin tuna (to the levels recommended by the Scientific Committee), including catch allocations for Members (on the basis of the catch figures indicated in the IOTC Scientific Committee report 2008). These proposals were submitted in response to the advice from the Scientific Committee that yellowfin tuna stocks are evaluated to be at levels near or below MSY; and recognizing the importance of applying the precautionary approach for the management of the stock in the Indian Ocean. However, after considerable debate, no consensus was reached on a formula to distribute the allowable catches between Members, and the proposals for catch limits were dropped from further consideration at this Session. The Chair encouraged Members interested in proposing similar measures to engage in consultations well in advance of the next Session, so as to increase the chances of adoption (IOTC, 2009a). In total, there are 3,363 vessels under Authorized Fishing Vessels as per 03 February 2009. Indonesia contributes the biggest portion of these vessels, contributing to 26% of them or about 874 vessels, followed by Iran (22.7%), European countries (14.6%), Japan (12.2%) and Republic of Korea (5.5%) (IOTC, 2009b).

Management of the tuna fisheries, as in other fisheries in Indonesia, is mainly by input controls through licensing, implementation of log book system, installment of a vessel monitoring system, and institutional strengthening. License is granted on the basis of fish stock utilization status, and a new license will not be issued when fish stock is fully or over exploited. Fishing fee is charged on the basis of resource rent. Tuna fishery protection also covered through regulation and limitation on the fishing fleets, fishing ground and fish landing. However, direct impact of protection still not found in the ground level.

Korean longliners operating in the Indian Ocean had 7.5% observer coverage in 2010 (Kim et al., 2011).

All Korean longliners and carrier vessels are equipped and operate a vessel monitoring system to monitor their fleets in the Indian Ocean (Kim et al., 2011), but it remains uncertain on whether such data is shared with IOTC for monitoring compliance issues.

National level measures:
Purse seining and gillnetiing for tuna and other species is banned.
There is a ban on shark fishing, but it has never been enforced to date.

The Sri Lankan Exclusive Economic Zone (EEZ) covers 517,000 km². Marine fisheries are divided into coastal (those fisheries taking place within the continental shelf and undertaken by the fishing craft in single day operations) and offshore/deep sea (those which take place outside the continental shelf and beyond extending up to the edge of the Exclusive Economic Zone and even in the high seas by multi-day boats) (MFAR 2007).

Management of Sri Lankan fisheries is conducted through the Ministry of Fisheries and Aquatic Sciences. The Fisheries and Aquatic Resources Act No 2 of 1996 is the prime code of rule for fisheries management in Sri Lanka. The significance provisions of this Act are:
- setting up a fisheries and aquatic resources advisory council;
- stipulation of the necessity and importance of preparing a plan for the management, regulation, conservation and development of fisheries and aquatic resources;
- designation of fisheries management areas;
- designation of fisheries committees;
- designation of management authorities;
- licensing of all types of marine fisheries introduced;
- inclusion of a section for aquaculture management;
- inclusion of provisions to collect information on all imported fish and fish products;
- stipulating a course of action to be followed in handling fishing disputes, and
- inclusion of more types of offences and penalties for them;

Research is conducted by the National Aquatic Resources Research and Development Agency.

Sri Lanka has a data collection and reporting system that has been advanced in recent years. The methods used to collect data include logbooks, vessel monitoring systems (VMS) and an observer program. The logbook program is already in place, while the VMS and observer programs were being tested during 2014. Observers are to be required on vessels larger than 24 ft. The logbook program became mandatory for vessels larger than 34 ft. in 2012. Sri Lanka has database in place to record logbook data. A new logbook will be implemented during 2015. Since 2012, Sri Lanka has produced catch and effort data through their port sampling program. In addition, Sri Lanka published a National Plan of Action for Illegal, Unregulated and Unreported fishing. Foreign vessels that are registered as an authorized vessel by the Indian Ocean Tuna Commission and have a valid National registration number are allowed to land fish in Sri Lanka. No transshipment is allowed in Sri Lankan ports (Hewapathirana et al. 2014).

Sri Lanka is a cooperating member of the Indian Ocean Tuna Commission and must comply with those management measures while operating in the high seas.

There is no TAC or other output controls for yellowfin tuna in the Indian Ocean. Therefore, compliance cannot be measured. However, the IOTC Scientific Committee has repeatedly pointed out that fishing levels of yellowfin tuna stock have exceeded MSY in recent years. Average annual catch over 2003-2007 was 369,912 tonnes, while the MSY was 330,000 tonnes.

In addition to that, IUU fishing in the Indian Ocean has been a major issue, which includes a range of illicit activities: fishing without permission or out of season; harvesting prohibited species; using outlawed types of fishing gear; disregarding catch quotas; or non-reporting or underreporting catch weights. Of particular concern are the western Indian Ocean and the maritime areas along the coast of eastern Africa. There, fishing vessels of various flags have taken advantage of the absence in coastal countries of strong enforcement mechanisms (FAO 2007). The Commission has regularly been also establishing a list of vessels presumed to have carried out illegal, unregulated and unreported fishing in the IOTC area.

The Scientific Committee also noted the increase in unreported catches from gillnet fisheries. A large number of vessels from Iran (42%), Sri Lanka (19%) and Pakistan (7%) are reported as operating on the high seas, but that the Secretariat has not received complete data sets from the countries involved.

IOTC Resolution on a Regional Scheme on Port State Measures to Combat Illegal, Unreported and Unregulated Fishing is proposed in the Meeting in 2009 which intention to contribute to the long-term conservation and sustainable use of living marine resources, and in particular of highly migratory stocks, in the IOTC Area through strengthened, harmonized and transparent port State measures to prevent, deter and eliminate illegal, unreported and unregulated (IUU) fishing.

In order to regulate and monitor the fishing activities, the Indonesian fisheries authority has issued regulations:

1) Ministerial regulation Number 05 year 2008 on the obligation for fishing vessels above 30 GT to install a Vessel Monitoring System, and to activate the transmitter.

2) Ministerial regulation Number 18 year 2010 which requires the use of logbook for vessels above 5 GT, which has to be submitted to the port authority prior to unloading the catch. The Indonesian fisheries authority has developed 3 logbook systems, one each for longline/handline, purse-seine/pole and line and other gears.

In 2011, a research institute for tuna fisheries (RITF) was established to conduct port sampling and a scientific observer program for tuna fisheries in the Indian Ocean. The number of scientific observer involved in 2012 was 7 observers. The average days at sea /trip varied from 30 d/trip to 94 d/trip, with the average total days at sea was 67 days. The Observer Program data set is currently the most comprehensive and most reliable data available from the tuna fisheries in term of catch and effort information.

Compliance of tuna fisheries in Indonesian waters can be assessed using the management target defined by MMAF for each tuna species as Total Allowable Catch set by the managers.

In 1998 and 2005, total catch of tuna exceeded the management target. In 2005, total catch of tuna in Eastern Indian Ocean reached 76 thousands t or about 2 thousands t more than its management target. Actual catches of tuna (excluding Skipjack) in Western Central Pacific Ocean also have been very close to the management target. In 2002, actual catch of tuna in this area was at level of management target (102 thousands t). However after that year, the actual catch started to decline until recently.

It is not easy to assess the compliance of this fishery since there is no set TAC by the fishery managers so far. However, compliance of tuna fisheries in Indonesian waters can preliminarily be assessed by using the single management target defined by MMAF for each tuna species as TAC (Total Allowable Catch) set by the managers.

Latest data from Indonesia Statistics of Capture Fisheries (2009) shows that actual catch for yellowfin tuna in Indonesia’s part of Indian Ocean (Hindia Ocean, Western Timor Sea, Bali Strait and Sawu Sea) have been far exceeding their management targets (or presumably set TACs).

In 2004, total catch of yellowfin tuna reached 42,862 tonnes, exceeding the management target by more than 30%.

See Management target (TAC) vs Actual Catch

It is not easy to assess the compliance of this fishery since there is no set TAC by the fishery managers so far. However, compliance of tuna fisheries in Indonesian waters can preliminarily be assessed by using the single management target defined by MMAF for each tuna species as TAC (Total Allowable Catch) set by the managers.

Latest data from Indonesia Statistics of Capture Fisheries (2009) shows that actual catch for yellowfin tuna in Indonesia’s part of Indian Ocean (Hindia Ocean, Western Timor Sea, Bali Strait and Sawu Sea) have been far exceeding their management targets (or presumably set TACs).

In 2004, total catch of yellowfin tuna reached 42,862 tonnes, exceeding the management target by more than 30%.

See Management target (TAC) vs Actual Catch

Compliance and enforcement of foreign tuna fishing vessels operating beyond the 75 nm limit is low (Huntington et al 2010).

Sri Lankan provides a report on compliance with Indian Ocean Tuna Commission management recommendations on an annual basis. According to the 2013 report, Sri Lanka has provided information on the majority of mandatory measures. Information on observer coverage, and the distribution of fishing catch and effort was not provided. Sri Lanka indicates that they are working towards implementing an observer program and working to refine their logbook and vessel monitoring programs. The Scientific Committee noted that there is some uncertainty surrounding reported catches of yellowfin tuna from coastal Sri Lankan fisheries. There is no total allowable catch limit for yellowfin tuna in the Indian Ocean (Hewapathirana et al. 2014)(IOTC 2014).

Indonesia has been recognized as the highest tuna-producing country in the world, contributing 15 percent of global tuna production in 2009 (FishStat 2006). Approximately 20% of Indonesia’s tuna production comes from the Indian Ocean, and 80% from the Western Central Pacific Ocean (FishStat 2006). Indonesian tuna fisheries are difficult to assess separately, and are often reported altogether because they cumulatively affect target stocks, specifically yellowfin tuna (YFT) and skipjack tuna, as well as other overexploited stocks such as bigeye tuna and baitfish (Moody Marine LTD 2010).

This narrative presents information for Indonesia’s handline fisheries in the Indian Ocean wherever possible; however, the majority of available information is for Indonesia’s tuna fisheries (purse seines not included here), specifically longline fisheries in the Indian Ocean. Thus, unless handline fisheries are specifically referenced, information presented here represents summaries across different tuna fisheries.

Although assumed to be highly selective in terms of catch, there is a high degree of uncertainty about the overall scale and potential impacts of the Indonesian handline fisheries targeting yellowfin tuna (YFT) on ETP species and the ecosystem. In 2010, there were 627 active vessels in the Indonesian handline fishery targeting YFT in the Indian Ocean (Moody Marine LTD 2010). However, Indonesia reported only 217 longline vessels overall in 2017, which presumably included handline vessels but did not specify the actual number (Ruchimat et al. 2018). This number was down from 1,311 vessels reported in 2016 (Ruchimat et al. 2017). There has apparently been a rapid and uncontrolled growth in tuna handliners in Indonesia as vessels convert from other gears (e.g., driftnets); in contrast to the official estimates of permit holders and active vessels described above, perhaps 34,000 small handline vessels targeting tunas regularly or seasonally, which contributes to significant uncertainty about cumulative target catch and bycatch (Moody Marine LTD 2010)). 

The Indian Ocean Tuna Commission (IOTC), of which Indonesia is a member, is responsible for management and conservation measures in international waters of the Indian Ocean. IOTC resolution 10/04 requires at least 5% of the total number of operations/sets for each gear type (including longlines) fishing with vessels ≥ 24 m in the IOTC area of competence, and < 24 m if they fish outside their EEZ (IOTC 2010). However, Indonesia’s country reports to the IOTC are inconsistent with respect to the ETP species reported as well as the ranges of years during which the bycatch was observed, which varied by species ((Ruchimat et al. 2017); (Ruchimat et al. 2018)). Observer coverage of Indonesian handline trips has fluctuated between 0 and 17 trips between 2013-2017 (Ruchimat et al. 2018), but it is unclear what proportional coverage these reported levels represent. Ministerial regulation No. 42/2015 requires all vessels above 30 GT or operating outside the EEZ to be equipped with a VMS transmitter (Ruchimat et al. 2018). RITF maintains a tuna catch monitoring program at Benoa Fishing Port in Bali to verify logbook reports, and has a goal of minimum 30% coverage of landings; Ruchimat et al. (Ruchimat et al. 2018) reported that coverage of port sampling between 2013-2017 was above 50%. These reports include sampling of some shark species (e.g., blue sharks, shortfin makos, oceanic whitetips, and bigeye thresher sharks) as well as billfish (e.g., blue marlin, black marlin, striped marlin, swordfish). 

Though some handline sets occur on free schools or natural objects, Indonesian handline fisheries focus on anchored fish aggregating devices (FADs). In some cases, handliners fish with permission on FADS that are owned and operated by purse seine companies, but most are unlicensed ((Moody Marine LTD 2010); (Hough 2018)). IOTC Resolution 18/08 sets limits on the total number of FADs that can be deployed, specifications of catch reporting, and development of FAD designs to reduce non-target catch, but this applies to purse seine vessels (IOTC 2013). No information was available in country reports about the number or location of FADs, an issue also highlighted by the MSC Pre-assessment (Hough 2018). 

Given the current observer coverage and reporting scheme in Indonesian longline fisheries, and handlines in particularly, estimates of total ETP bycatch by species are not possible. This fishery overlaps with several shark, seabird, marine mammal, and sea turtle populations, some of which are currently low abundance and declining, which means that numerically low bycatch interactions can still have significant population impacts (Lewison et al. 2014). 

Previous reports suggest limited interactions with ETP species which are unlikely to hinder recovery ETP species; large handline vessels are most likely to have any interactions with ETP species ((Poseidon Aquatic Resource Management Ltd 2016); (Hough 2018)). However, this assertion was based on anecdotal information and inference from other handline fisheries; direct observation and reporting of ETP bycatch for this fishery is unavailable ((Hough 2018)). 

Recent ecological risk assessments for shark species caught in IOTC reported uncertain stock status determinations for oceanic whitetip, shortfin mako, scalloped hammerheads, bigeye and pelagic thresher sharks, and silky sharks, and concluded that blue sharks were not overfished (IOTC 2019).

Despite conservation measures in place, Indonesia is one of the world’s top shark producers ((Lack et al. 2006); (Blaber et al., 2009)), and most shark products come from bycatch (72%) ((Zainudin 2011); cited in (Zainudin et al. 2017)). Shark bycatch from tuna fleets comprised approximately 11% of shark landings in Indonesia between 2011 and 2005 (Blaber et al., 2009). In addition, shark finning on Indonesian vessels is prohibited in some parts of the longline fishery (under AP2HI, for example) but finning is unlikely to be prevented on these vessels (Poseidon Aquatic Resource Management Ltd 2016). Many shark and ray species in Indonesia are overfished and effective management strategies likely need to include gear restrictions and catch limits, as well as controls on the fin trade (Blaber et al., 2009).

Indonesia established a National Plan of Action (NPOA) for sharks and rays for 2015-2019. The Minister of Marine and Fisheries issued regulations (No. 34/PERMEN-KP/2015 and amendment No. 59/PERMEN-KP/2014) that prohibits export of oceanic whitetip sharks and hammerhead sharks and fins from Indonesian territory (Ruchimat et al. 2018). Blue sharks (mostly retained) and crocodile sharks (typically discarded dead) comprised the majority of shark bycatch during 2013-2017 according to Research Institute for Tuna Fisheries (RITF) observer data (Ruchimat et al. 2018).

IOTC has established several conservation measures targeting ETP species, including cetaceans (IOTC 2013), multiple shark species ((IOTC 2016); (IOTC 2017)), billfish (IOTC 2015), seabirds (IOTC 2012), marine turtles (IOTC 2012).

The Indian Ocean Tuna Commission (IOTC), of which Indonesia is a member, is responsible for management and conservation measures in international waters of the Indian Ocean. IOTC resolution 10/04 requires at least 5% of the total number of operations/sets for each gear type (including longlines) fishing with vessels ≥ 24 m in the IOTC area of competence, and < 24 m if they fish outside their EEZ (IOTC 2010). However, Indonesia’s country reports to the IOTC are inconsistent with respect to the ETP species reported as well as the ranges of years during which the bycatch was observed, which varied by species ((Ruchimat et al. 2017); (Ruchimat et al. 2018)). Observer coverage increased by 6.9% of all longline vessels from 2016 to 2017, but the Indonesian country report to the IOTC was unclear about what proportion of overall fishing effort this coverage achieved ((Ruchimat et al. 2017); (Ruchimat et al. 2018)). Ministerial regulation No. 42/2015 requires all vessels above 30 GT or operating outside the EEZ to be equipped with a VMS transmitter ((Ruchimat et al. 2018)). RITF maintains a tuna catch monitoring program at Benoa Fishing Port in Bali to verify logbook reports, and has a goal of minimum 30% coverage of landings; Ruchimat et al. ((Ruchimat et al. 2018)) reported that coverage of port sampling between 2013-2017 was above 50%. These reports include sampling of some shark species (e.g., blue sharks, shortfin makos, oceanic whitetips, and bigeye thresher sharks) as well as billfish (e.g., blue marlin, black marlin, striped marlin, swordfish).

In addition, IOTC Resolution 18/08 sets limits on the total number of FADs that can be deployed, specifications of catch reporting, and development of FAD designs to reduce non-target catch, but this applies to purse seine vessels (IOTC 2013). No information was available in country reports about the number or location of FADs, an issue also highlighted by the MSC Pre-assessment (Hough 2018). 

Given the current observer coverage and reporting scheme in Indonesian longline fisheries estimates of total ETP bycatch by species are not possible. This fishery overlaps with several shark, seabird, marine mammal, and sea turtle populations, some of which are currently low abundance and declining, which means that even if numerically low, bycatch interactions can still have significant population impacts (Lewison et al. 2014). Addition types of information, such as post-release mortality of ETP species ((García-Párraga et al. 2014); (Musyl et al. 2015); (Musyl and Gilman 2019)), will also be necessary to robustly estimate the impacts of bycatch in Indonesian longline tuna fisheries.

RITF observers documented 76 total interactions with seabirds between 2005 to 2017 in Indonesian longlines in the Indian Ocean, including 20 in 2017 alone, 18 of which were great-winged petrels ((Ruchimat et al. 2018). Most seabird interactions have occurred in temperate latitudes (>25S). The Indonesian longline fishery in the Indian Ocean overlaps with several proposed or confirmed Important Bird Areas designated by BirdLife International, including one confirmed for IUCN Critically Endangered Christmas frigatebirds (BirdLife International 2019). Indonesia’s Ministry of Marine Affairs and Fisheries released Ministerial Decree (PERMEN KP) No. 12/2012 which requires use of tori lines for every longline vessel operating beyond 25S.

RITF observers documented 46 interactions with sea turtles during 2013-2017, 38 of which were with olive ridley turtles and the rest green turtles (Ruchimat et al. 2018). In a separate study that possibly used some of the same observer data, 43 interactions with sea turtles occurred during 2011-2016, 40 of which were olive ridleys as well as 1 leatherback and 2 unidentified species (WWF 2013). Bycatch assessments (observers as well as port-based interviews) conducted by WWF during 2005-2007 reported 132 sea turtles taken as bycatch (only 7 dead) in longlines and trawls, including green turtles, leatherbacks, loggerheads, and olive ridleys, though species-specific totals were not provided (Moody Marine LTD 2010). Indonesian longline fishing operations occur in a highly diverse area in terms of marine turtle regional management units (RMUs; (Wallace et al. 2010), potentially overlapping with 9 different RMUs of 6 different species, including Southeast and Northeast Indian green turtles, West Pacific/Southeast Asia and Southeast Indian hawksbills, Southeast Indian loggerheads, West Pacific and Northeast Indian leatherbacks, West Pacific olive ridleys, and possibly Southeast Indian flatbacks. 

Six species of billfish were also caught by Indonesian tuna longlines, but most billfish catch was comprised of swordfish, black marlin, and blue marlin (Ruchimat et al. 2018). No marine mammal or whale shark bycatch was reported during 2012-2016 by RITF observers (Ruchimat et al. 2018). 

As part of a WWF-supported on-board observer program, Zainudin et al. ((Zainudin et al. 2017)) reported 26 seabirds, 17 dolphins, and 8 whales were caught between 2006-2014 across 71 tuna longline vessels operating out of Benoa Port in Bali (n=41 vessels) and Bitung Port in North Sulawesi (n=30 vessels). Three-quarters of seabird interactions were fatal, whereas between a quarter and one-third of shark, dolphin, and whale interactions were fatal. This study also reported that longlines out of Bali and out of North Sulawesi (WCPO region) caught a combined 2,095 sharks, nearly 96% of which were juveniles. Night fishing was correlated with low occurrence of seabird and shark bycatch, but higher cetacean bycatch. Overall, bycatch rates for seabirds, marine mammals, and sharks in Indonesian longlines reported in this study were lower than those reported in USA fisheries (Atlantic and Pacific). It is unclear the degree of complementarity of the observer data reported by Zainudin et al. ((Zainudin et al. 2017)) and those reported by Indonesia to the IOTC (Ruchimat et al. 2018)).

Recent ecological risk assessments for shark species caught in IOTC reported uncertain stock status determinations for oceanic whitetip, shortfin mako, scalloped hammerheads, bigeye and pelagic thresher sharks, and silky sharks, and concluded that blue sharks were not overfished (IOTC 2019).

Despite conservation measures in place, Indonesia is one of the world’s top shark producers ((Lack et al. 2006); (Blaber et al., 2009)), and most shark products come from bycatch (72%) (Zainudin 2011); cited in (Zainudin et al. 2017). Shark bycatch from tuna fleets comprised approximately 11% of shark landings in Indonesia between 2011 and 2005 (Blaber et al., 2009). In addition, shark finning on Indonesian vessels is prohibited in some parts of the longline fishery (under AP2HI, for example) but finning is unlikely to be prevented on these vessels (Poseidon Aquatic Resource Management Ltd 2016). Many shark and ray species in Indonesia are overfished and effective management strategies likely need to include gear restrictions and catch limits, as well as controls on the fin trade (Blaber et al., 2009).

Indonesia established a National Plan of Action (NPOA) for sharks and rays for 2015-2019. The Minister of Marine and Fisheries issued regulations (No. 34/PERMEN-KP/2015 and amendment No. 59/PERMEN-KP/2014) that prohibits export of oceanic whitetip sharks and hammerhead sharks and fins from Indonesian territory (Ruchimat et al. 2018). Blue sharks (mostly retained) and crocodile sharks (typically discarded dead) comprised the majority of shark bycatch during 2013-2017 according to Research Institute for Tuna Fisheries (RITF) observer data (Ruchimat et al. 2018).

IOTC has established several conservation measures targeting ETP species, including cetaceans (IOTC 2013), multiple shark species ((IOTC 2017)), billfish (IOTC 2015), seabirds (IOTC 2012), marine turtles (IOTC 2012).

The Indonesian fisheries authority issued the Minsiterial decree number 12 year 2012 to regulate the management and conservation of bycatch and ecologically related species on tuna fisheries, which includes sharks, turtles, seabirds and mammals (Ruchimat et al. 2018).

Indonesia has a Ministerial Decree (PERMEN KP) No. 12/2012 which requires the use of tori lines on vessels operating beyond 250 south and Indonesia has a National Plan of Action for Seabirds in place since 2016 (Ruchimat et al. 2018).

Indonesia has a National Plan of Action for Marine Turtles for 2015-2020 (Ruchimat et al. 2018).

Bycatch of seabirds, sea turtles, marine mammals and sharks in purse seine and pelagic longline tuna fisheries threatens some populations with extinction.Bycatch of juvenile tunas and unmarketable species and/or sizes of other fish in purse seine fisheries, and juvenile swordfish in longline fisheries, contributes to the overexploitation of some stocks, and is an allocation issue among gear types and fishing nations (Gilman and Lundin, 2010; Gilman, In Press).

Yellowfin tuna are harvested with a diverse variety of gear types, from small-scale artisanal fisheries in Pacific Island and Southeast Asian waters to large, distant-water longliners and purse seiners that operate widely in equatorial and tropical waters. Purse seiners catch a wide size range of yellowfin tuna, whereas the longline fishery takes mostly adult fish (WCPFC 2007).

IOTC sea turtle CMM
A 2009 resolution requires members to report data on sea turtle interactions and for vessels to follow sea turtles handling and release guidelines and posses and use specified turtle release equipment (IOTC, 2009c).Purse seine vessels are required to: (i) Avoid encircling sea turtles; (ii) when a turtle is encircled or entangled, take measures to safely release the turtle, including stopping the net roll as soon as the turtle comes out of the water, disentangling the turtle before resuming net roll, and to the extent practicable, resuscitating the turtle before returning it to the water; and (iii) release all turtles observed entangled in FADs or other gear.Longline vessels are encouraged to use whole fish bait.

IOTC shark CMM
A 2005 resolution requires: (i) annual reporting of data on shark catches; (ii) keep all parts of retained sharks, excluding head, guts and skins, to the point of first landing; (iii) have onboard fins that total < 5% of the weight of sharks onboard, up to the first point of landing, or otherwise ensure compliance with the 5% rule through certification, observer monitoring or other method (IOTC, 2005).IOTC (2010c) prohibits the retention, transshipment or landing of all species of thresher sharks, intended to address concerns over the status of the bigeye thresher shark (Aliopias superciliosus), but applicable to all thresher species due to the difficulty in differentiating between bigeye and other thresher species.

IOTC CMM relating to bycatch of Juvenile and Small Tunas / Unmarketable Species and/or Sizes of Fish
Temporal one month per year closure to longline and purse seine vessels of an area off Somalia is in effect from 2011 to 2012 (IOTC, 2010a).Encourages retention and landing of all purse seine-caught bigeye, skipjack and yellowfin, and incidental species (IOTC, 2010d).

IOTC conducted a Level 2 ecological risk assessment across species subject to fishing mortality in purse seine and longline fisheries (Mura et al., 2009).

There are extremely low bycatch levels in pole-and-line fisheries. Discards are believed to have high post release survival rates due to the use of barbless hooks and flick-off practices (FAO, 1997). However, concern over bycatch of reef fish and juvenile classes of target species in baitfish fisheries that supply live bait to pole-and-line fisheries has been raised, as have other ecological issues (ecosystem effects of removal of baitfish species, overexploitation of target baitfish species, habitat degradation) and socioeconomic issues (food security impacts with coastal communities) (FAO, 2008; Gillett, 2010).

Required observer coverage rates and compliance with these rates are low in the Indian Ocean. In 2016, the Commission adopted a new resolution to develop a pilot program to promote the regional observer scheme of the IOTC {IOTC 2016}. Indonesia has implemented an observer program that extends to the hook and line fisheries (Ruchimat et al. 2018).

Fishing gears for the tuna fishery in Indonesia are longliner, traditional hook & line, and purse-seiner combined with FADs – Fish Aggregation Devices. Longline fishing is controversial in some areas because the lines can lead to bycatch, in endangered species such as sea turtles and this can sometimes have a significant effect on populations.

NOAA Fisheries has provided funding to World Wildlife Fund-Indonesia (WWF) to supportsea turtle conservation and management institutional capacity building Indonesia. The focus is on commercial and traditional fisheries with significant sea turtle interactions. The project emphasizes participation of the industry on a voluntary basis and works closely with recognized industry groups, including the Indonesia Tuna Association (ASTUIN) and the Indonesia Tuna Longline Association (ATLI).

Through this project, sea turtle bycatch in tuna longline industries in Indonesia was surveyed from May to September 2005 in several fishing ports, i.e. Muara Baru (Jakarta), Cilacap (Central Java), Bitung (North Sulawesi), Kendari/Bau-bau (Southeast Sulawesi) and Makassar/Bone (South Sulawesi). Longline fishermen (boat captains and crews) and non-longline fishermen (i.e. those using gillnets and purse seine) were interviewed. Most respondents (95%) acknowledged usually catching at least one sea turtle per month. With an estimated 1,600 Indonesian tuna longline vessels catching three sea turtles per trip (one trip takes three months on average), the average sea turtle bycatch is estimated to range from 6,400 to 19,200 animals per annum (p.a.). The most common sea turtle bycatch species in both the Indian and Pacific Oceans is loggerhead turtles. Leatherback turtles were also frequently caught in both oceans, although catch rates in the Pacific Ocean were higher. Indonesian tuna longline bycatch in the Pacific is estimated to be 256 to 768 animals p.a. for leatherback turtles and 768 to 2,304 animals p.a. for loggerhead turtles. In the Indian Ocean, bycatch for leatherback turtles is estimated to be 1,349 to 4,032 animals p.a., while bycatch for loggerhead turtles is 4,032 to 12,098 animals p.a. This Indian Ocean estimate exceeds Lewison’s (2004) bycatch calculation for the year 2000, of 4,000 leatherback turtles and 6,000 loggerhead turtles, and confirms the importance of longline fisheries in bycatch issues in Indonesia.

Together with some early adopters in the Tuna longline (Pelabuhan Ratu-West Java, Benoa-Bali, Bitung-North Sulawesi) and shrimp trawl fisheries industries (Sorong-Papua), WWF initiated trial observer programs and trained crew members on appropriate release techniques that can increase survival rates of turtles captured in the gear. Gear trials will soon be implemented adjusting long-line hooks with a more circular model that reduces the hook-up rate of turtles and allows for easier release in case a turtle is hooked after all.However, since the hook is still imported from USA, then the implementation of it is still on piloting scheme (under collaboration program of WWF Indonesia and the Research Center of Captured Fisheries Ministry of Marine Affairs and Fisheries (Lovita, 2007).

There are extremely low bycatch levels in pole-and-line fisheries. Discards are believed to have high post release survival rates due to the use of barbless hooks and flick-off practices (FAO, 1997). However, concern over bycatch of reef fish and juvenile classes of target species in baitfish fisheries that supply live bait to pole-and-line fisheries has been raised, as have other ecological issues (ecosystem effects of removal of baitfish species, overexploitation of target baitfish species, habitat degradation) and socioeconomic issues (food security impacts with coastal communities) (FAO, 2008; Gillett, 2010).

Required observer coverage rates and compliance with these rates are low in the Indian Ocean. In 2016, the Commission adopted a new resolution to develop a pilot program to promote the regional observer scheme of the IOTC {IOTC 2016}. Indonesia has implemented an observer program that extends to the hook and line fisheries (Ruchimat et al. 2018).

There are extremely low bycatch levels in pole-and-line fisheries. Discards are believed to have high post release survival rates due to the use of barbless hooks and flick-off practices (FAO, 1997). However, concern over bycatch of reef fish and juvenile classes of target species in baitfish fisheries that supply live bait to pole-and-line fisheries has been raised, as have other ecological issues (ecosystem effects of removal of baitfish species, overexploitation of target baitfish species, habitat degradation) and socioeconomic issues (food security impacts with coastal communities) (FAO, 2008; Gillett, 2010).

Required observer coverage rates and compliance with these rates are low in the Indian Ocean. In 2016, the Commission adopted a new resolution to develop a pilot program to promote the regional observer scheme of the IOTC {IOTC 2016}. Malaysia has not yet implemented an observer program (Samsudin et al. 2018).

Huntington et al (2010) report that interactions with PET species is low, but lack of adequate scientific data leads to absence of any credible conclusions on this issue.

Yellowfin tuna schools have often observed associated with Bryde’s whales (Balaenoptera edeni) as both feed on same prey (Anderson, 1993; Anderson et al., 1998). Yellowfin tuna have also been frequently observed in schools of spotted dolphins and spinner dolphins (Anderson 2005).

There are extremely low bycatch levels in pole-and-line fisheries. Discards are believed to have high post release survival rates due to the use of barbless hooks and flick-off practices (FAO, 1997). However, concern over bycatch of reef fish and juvenile classes of target species in baitfish fisheries that supply live bait to pole-and-line fisheries has been raised, as have other ecological issues (ecosystem effects of removal of baitfish species, overexploitation of target baitfish species, habitat degradation) and socioeconomic issues (food security impacts with coastal communities) (FAO, 2008; Gillett, 2010).

Required observer coverage rates and compliance with these rates are low in the Indian Ocean. In 2016, the Commission adopted a new resolution to develop a pilot program to promote the regional observer scheme of the IOTC {IOTC 2016}. Oman has not yet implemented an observer program (DGFRD 2018).

Bycatch of seabirds, sea turtles, marine mammals and sharks in purse seine and pelagic longline tuna fisheries threatens some populations with extinction. Bycatch of juvenile tunas and unmarketable species and/or sizes of other fish in purse seine fisheries, and juvenile swordfish in longline fisheries, contribute to the overexploitation of some stocks, and is an allocation issue among gear types and fishing nations (Gilman, 2011). Bycatch of several vulnerable species groups, including sea turtles, marine mammals and sharks, has been documented in gillnet fisheries (e.g., Gilman et al., 2009).

IOTC conducted a level 2 assessment across species subject to fishing mortality in various purse seine and longline fisheries (Murua et al., 2006). Findings were that pelagic and coastal sharks and teleosts are of relatively highest risk from mortality in assessed longline and purse seine fisheries.

The following binding measures have been adopted by IOTC to address bycatch in IOTC-managed longline and purse seine tuna fisheries (Gilman, 2011):

Seabirds: A 2010 resolution, superseding previous measures, requires, when south of 25ºS, use of at least two seabird mitigation methods selected from two lists of nine alternatives.

Sea turtles: A 2009 resolution requires members to report data on sea turtle interactions and for vessels to follow sea turtles handling and release guidelines and possess and use specified turtle release equipment. Longline vessels are encouraged to use whole fish bait.

Sharks: A 2005 resolution requires: (i) annual reporting of data on shark catches; (ii) keep all parts of retained sharks, excluding head, guts and skins, to the point of first landing; (iii) have onboard fins that total < 5% of the weight of sharks onboard, up to the first point of landing, or otherwise ensure compliance with the 5% rule through certification, observer monitoring or other method. IOTC prohibits the retention, transshipment or landing of all species of thresher sharks, intended to address concerns over the status of the bigeye thresher shark (Aliopias superciliosus), but applicable to all thresher species due to the difficulty in differentiating between bigeye and other thresher species.

Juvenile tunas: To ease pressure on juvenile and small tunas, temporal one month per year closure to longline and purse seine vessels of an area off Somalia is in effect from 2011 to 2012.

Longline fisheries typically capture incidental bycatch species including sea turtles and sea birds and potentially marine mammals. There are five Acts in Sri Lanka that pertain to the protection and management of these bycatch species. These include 1) Fauna and Flora protection Act 1937, 2)Fisheries and Aquatic Resources Act NO. 2 (1996), 3) National Environment Act NO. 47 1980, 4) Coast Conservation Act 1981 and 5) Marine Pollution Prevention Act of Sri Lanka.

The National Aquatic Resources and Research (NARA) Development Agency has conducted on-board research studies to examine bycatch interactions. Sri Lanka reports that sea bird interactions do not occur in their fisheries due to the location of the fisheries and the nature of the fisheries. For example, Sri Lanka indicates that the small nature of their longline vessels reduces any potential sea bird interactions from occurring. 

Sea turtles are protected under the Fauna and Flora Protection Act and Fisheries and Aquatic Resources Act. Large-scale drift gillnets are restricted to being 2.5 km in length or less, which reduces turtle entanglements. Longlines typically use circle and not “J” hooks. During 2017, 34 olive ridley, 45 green, 7 hawksbill and 10 leatherback sea turtles were observed as incidentally captured in the longline fishery (Hewapathirana et al. 2018).

Marine mammals are prohibited from being captured in Sri Lanka under the Fisheries and Aquatic Resources Act No. 2. No recordings of incidental captures of marine mammals have been made in Sri Lanka. However, logbook recordings are poor and therefore the NARA will be conducted research on marine mammals in the future (Hewapathirana et al. 2014).

In addition, because Sri Lanka is a cooperating member of the IOTC they must comply with their management measures. Vessels must take reasonable steps to release any incidentally captured cetaceans and to report incidental captures {IOTC 2013l}. Any interactions between vessel and sea turtles must be reported to the Commission and fishermen are required to attempt proper mitigation measures, aid in recovery when necessary and release all incidentally captured sea turtles. Longline vessels must carry line cutters and dehooking devices. Countries are also requested to conduct studies on the use of circle hooks and whole finfish bait, handling techniques and other mitigation measures. {IOTC 2013l}. All interactions with sea birds must be recorded and countries must provide information on how they are implementing observer programs to aid in the recording and reporting of these interactions. Mitigation measures are required, south of 25 degrees two pre-approved mitigation measures must be used, but mitigation methods in other areas must be used as well {IOTC 2013l}.

Thai vessels do not record interactions with marine mammals in the Indian Ocean (Saikliang and Nootmorn 2011).

Bycatch of seabirds, sea turtles, marine mammals and sharks in purse seine and pelagic longline tuna fisheries threatens some populations with extinction. Bycatch of juvenile tunas and unmarketable species and/or sizes of other fish in purse seine fisheries, and juvenile swordfish in longline
fisheries, contribute to the overexploitation of some stocks, and is an allocation issue among gear types and fishing nations (Gilman, 2011). Bycatch of several vulnerable species groups, including sea turtles, marine mammals and sharks, has been documented in gillnet fisheries (e.g., Gilman et al., 2009).

IOTC conducted a level 2 assessment across species subject to fishing mortality in various purse seine and longline fisheries (Murua et al., 2006). Findings were that pelagic and coastal sharks and teleosts are of relatively highest risk from mortality in assessed longline and purse seine fisheries. The following binding measures have been adopted by IOTC to address bycatch in IOTC-managed longline and purse seine tuna fisheries (Gilman, 2011):

Seabirds: A 2010 resolution, superseding previous measures, requires, when south of 25oS, use of at least two seabird mitigation methods selected from two lists of nine alternatives.

Sea turtles: A 2009 resolution requires members to report data on sea turtle interactions and for vessels to follow sea turtles handling and release guidelines and possess and use specified turtle release equipment. Longline vessels are encouraged to use whole fish bait.

Sharks: A 2005 resolution requires: (i) annual reporting of data on shark catches; (ii) keep all parts of retained sharks, excluding head, guts and skins, to the point of first landing; (iii) have onboard fins that total < 5% of the weight of sharks onboard, up to the first point of landing, or otherwise ensure compliance with the 5% rule through certification, observer monitoring or other method. IOTC prohibits the retention, transshipment or landing of all
species of thresher sharks, intended to address concerns over the status of the bigeye thresher shark (Aliopias superciliosus), but applicable to all thresher species due to the difficulty in differentiating between bigeye and other thresher species.

Juvenile tunas: To ease pressure on juvenile and small tunas, temporal one month per year closure to longline and purse seine vessels of an area off Somalia is in effect from 2011 to 2012. Encourages retention and landing of all purse seine-caught bigeye, skipjack and yellowfin, and incidental species.

Reefish are used as baitfish in the pole and line fishery around Lakshadweep islands. Caesionids (Spratelloides delicatulus), clupeids, and apogonids are the principal fish caught for use as baitfish around Minicoy islands (Naseer 1999; Lakshadweep Development Report 2007). Over the years, increase in pole and line fishing effort has lead to seasonal shortage of baitfish in many of the Lakshadweep islands (Gopakumar 1991).

Bait fish is collected from lagoon and reeef areas around Minicoy, Agatti, Suheli, Perumal Par, Valiapani, Bitra and Cheriapani (Lakshadweep Development Report 2007). A detailed study of different species exploited in the bait fish fisheries is available in Gopakumar, et.al., (1991); Pillai, et. al., (2002).

Other fish which are caught as bycatch in handline and hook & line fisheries include snappers, groupers, baracudas, carangids, dolphin fish, perches, sharks and rays. These fish constitute around one fourth of the total fish production in the islands caught using traditional gear like hook and line, surface trolling and other minor gears.

There are extremely low bycatch levels in pole-and-line fisheries, where bycatch that does occur generally consists of juvenile kawakawa tuna (Euthynnus affinis), frigate mackerel (Auxis rochei), mahimahi (Coryphaena hippurus), and rainbow runner (Elagatis bupinnulata). Discards are believed to have high post release survival rates due to the use of barbless hooks and flick-off practices (FAO, 1997). However, concern over bycatch of reef fish and juvenile classes of target species in baitfish fisheries that supply live bait to pole-and-line fisheries has been raised, as have other ecological issues (ecosystem effects of removal of baitfish species, overexploitation of target baitfish species, habitat degradation) and socioeconomic issues (food security impacts with coastal communities) (FAO, 2008; Gillett, 2010).

Indonesian longliners also capture species such as sharks, billfish and other tunas. The scientific observer program in Indonesia began in 2005 through a collaborative project with Australia. The program became fully funded through Indonesia in 2011. The IOTC requires 5% observer coverage on longline vessels operating within the Convention Area.

Observer records from 2013 indicate that 121 individual sharks, representing nine species, were observed caught. The two most commonly caught shark species were the crocodile shark (Pseudocarcharias kamoharai_) and blue shark (Prionace glauca_). Indonesia has made progress on their National Plan of Action for sharks and is working towards adopting nation wide shark quotas for some species. Two species of manta rays (Manta birostris and Manta alfredi) have been given protection in Indonesian waters. Billfish made up 6.3% of the observed longline catch during 2013. The most commonly caught species were swordfish (~50%). Black, blue and striped marlin along with shortbill spearfish were also represented in the catch (Iritano et al. 2014). Observer records from 2013-2017 indicate blue and crocodile sharks dominated the catch. Crocodile sharks are typically discarded dead, while blue sharks are retained. Between 2005 and 2017, billfish made up about 5% of the total catch. Swordfish are the most common billfish species, followed by black marlin, blue marlin and sailfish. Pomfret, sickle pomfret, escolar and lancet fish are also incidentally captured in this fishery (Ruchimat et al. 2018).

Sharks: A 2005 *(updated in 2017) resolution requires: (i) annual reporting of data on shark catches; (ii) keep all parts of retained sharks, excluding head, guts and skins, to the point of first landing; (iii) have onboard fins that total < 5% of the weight of sharks onboard, up to the first point of landing, or otherwise ensure compliance with the 5% rule through certification, observer monitoring or other method. IOTC prohibits the retention, transshipment or landing of all species of thresher sharks, intended to address concerns over the status of the bigeye thresher shark (Aliopias superciliosus), but applicable to all thresher species due to the difficulty in differentiating between bigeye and other thresher species (IOTC 2017) (IOTC 2013).

In October 2010, Indonesia produced a National Plan of Action for Sharks (NPOA-Shark), which addresses key issues and actions for shark and ray management in Indonesia. The key actions suggested in the NPOA include: 1) Review of the status of shark- and ray fisheries in Indonesia. 2) Compilation of methods and data collection process. 3) Development of shark and ray research. 4) Improvement of management measures 5) Raising of concerns and awareness concerning the shark and ray fisheries in Indonesia. 6) Institutional Strengthening. As a member of the Indian Ocean Tuna Commission (IOTC) since 2007, Indonesia is required to comply with the Commission’s resolution 10/12, concerning the protection of thresher sharks. Minister of Marine Affairs No. 59/PERMEN-KP/2014 relates to the prohibition of retaining oceanic whitetip sharks and hammerhead sharks. A National Plan of Action for rays (2015-2019) has also been established by Indonesia (Ruchimat et al. 2018).

IOTC established a regional observer program in 2009, which will require 5% coverage of sets for vessels > 24 m overall length for each gear type while fishing in the IOTC Area (AIDCP, 2009a).IOTC will further require, by January 2013, 5% coverage for vessels < 24 m overall length when fishing at grounds outside their Exclusive Economic Zone (AIDCP, 2009a; IOTC, 2010e).The IOTC observer program will be operated by Member states (IOTC, 2010e).

There are extremely low bycatch levels in pole-and-line fisheries, where bycatch that does occur generally consists of juvenile kawakawa tuna (Euthynnus affinis), frigate mackerel (Auxis rochei), mahimahi (Coryphaena hippurus), and rainbow runner (Elagatis bupinnulata). Discards are believed to have high post release survival rates due to the use of barbless hooks and flick-off practices (FAO, 1997). However, concern over bycatch of reef fish and juvenile classes of target species in baitfish fisheries that supply live bait to pole-and-line fisheries has been raised, as have other ecological issues (ecosystem effects of removal of baitfish species, overexploitation of target baitfish species, habitat degradation) and socioeconomic issues (food security impacts with coastal communities) (FAO, 2008; Gillett, 2010).

Data from IOTC (2005) noted that based on research vessel undertook purse seine and longline fishing in the eastern Indian Ocean between 2001 and 2005, about fifteen families with about 30 species of fishes and one family of octopus were caught by purse seine and longline operations targeted and caught yellowfin, bigeye and skipjack tunas. Other species caught included mainly sharks (thresher, blue, white-tip, spot tail, crocodile and silky) and also stringrays.

There are extremely low bycatch levels in pole-and-line fisheries, where bycatch that does occur generally consists of juvenile kawakawa tuna (Euthynnus affinis), frigate mackerel (Auxis rochei), mahimahi (Coryphaena hippurus), and rainbow runner (Elagatis bupinnulata). Discards are believed to have high post release survival rates due to the use of barbless hooks and flick-off practices (FAO, 1997). However, concern over bycatch of reef fish and juvenile classes of target species in baitfish fisheries that supply live bait to pole-and-line fisheries has been raised, as have other ecological issues (ecosystem effects of removal of baitfish species, overexploitation of target baitfish species, habitat degradation) and socioeconomic issues (food security impacts with coastal communities) (FAO, 2008; Gillett, 2010).

Data collection on bycatch is poor for Korean longliners operating in the Indian Ocean, especeially for marine turtles and marine mammals. Limited data is available on bycatch of sharks caught by Korean longliners operating in the Indian Ocean. In 2010, 11 mt of sharks were retained by Korean longliner, while 54,358 kgs of blue sharks, 1796 kgs of Mako sharks were reported by longliners (Kim et al., 2011).

15 Yellow nosed albatross, 24 Black browed albatross, 9 Buller’s albatross, 1 Cape petrel, 2 Grey headed albatross, 1 Southern Giant albatross, 11 Wandering albatross and 3 Shy albatross were observed through national observer porgram in the IOTC region (Kim et al., 2011).

There are extremely low bycatch levels in pole-and-line fisheries, where bycatch that does occur generally consists of juvenile kawakawa tuna (Euthynnus affinis), frigate mackerel (Auxis rochei), mahimahi (Coryphaena hippurus), and rainbow runner (Elagatis bupinnulata). Discards are believed to have high post release survival rates due to the use of barbless hooks and flick-off practices (FAO, 1997). However, concern over bycatch of reef fish and juvenile classes of target species in baitfish fisheries that supply live bait to pole-and-line fisheries has been raised, as have other ecological issues (ecosystem effects of removal of baitfish species, overexploitation of target baitfish species, habitat degradation) and socioeconomic issues (food security impacts with coastal communities) (FAO, 2008; Gillett, 2010).

6 species of marine turtles are reported to interact with tuna fisheries in the Indian Ocean (IOTC 2011). However, there are no reported interactions between pole and line fisheries with turtles or marine mammals in Maldives tuna fisheries.
Relatively small quantities of yellowfin tuna are caught as by-catch in the pole and line fisheries. Substantial quantities of skipjack are caught around FADS, which can lead to unwanted by-catch of many non-target species. Livebait used in the pole and line tuna fisheries needs to be quantified on a regular basis. Discards in the skipjack targeted pole and line fisheries have not been formally quantified. Collection of baitfish is not monitored and operations during the night using lights can lead to unwanted by-catch of other non-target species.

There are extremely low bycatch levels in pole-and-line fisheries, where bycatch that does occur generally consists of juvenile kawakawa tuna (Euthynnus affinis), frigate mackerel (Auxis rochei), mahimahi (Coryphaena hippurus), and rainbow runner (Elagatis bupinnulata). Discards are believed to have high post release survival rates due to the use of barbless hooks and flick-off practices (FAO, 1997). However, concern over bycatch of reef fish and juvenile classes of target species in baitfish fisheries that supply live bait to pole-and-line fisheries has been raised, as have other ecological issues (ecosystem effects of removal of baitfish species, overexploitation of target baitfish species, habitat degradation) and socioeconomic issues (food security impacts with coastal communities) (FAO, 2008; Gillett, 2010).

Large longline vessels generally catch older age classes of bigeye tuna (Thunnus obesus) and bluefin tunas (T. maccoyii [southern], T. orientalis [Pacific] and T. thynnus [Atlantic]) for the sashimi market and some longline fleets target albacore (T. alalunga) for canning.Purse seine vessels target younger age classes of skipjack (Katsuwonus pelamis) and yellowfin (T. albacares) tuna for canning with incidental catch of bigeye tuna

Smaller swordfish are often discarded in pelagic longline tuna fisheries due to minimum size requirements or low market value (Cramer, 2003; Ward et al., 2008).

In addition to target tuna species (bigeye, skipjack and yellowfin), billfish, sharks and rays are also incidentally captured in Sri Lanka’s fisheries. In 2013, bycatch made up 3% of the total catch, with sharks and rays being the primary represented species. Bycatch of sharks is reported to occur more frequently in the gillnet and longline/gillnet combination fisheries compared to the longline fishery. In the longline fishery blue and silky sharks are the primary incidentally captured shark species. Overall, silky shark made up 68% of the reported shark catch during 2013. The longline fishery also catches billfish and other bony fish such as mahi mahi (Hewapathirana et al. 2018).

Sri Lanka has a National Plan of Action for Sharks that was made public in 2014. There is a species identification guide available, on-site sampling programs have been improved to include all species of sharks, Sri Lanka enforces the rules that sharks must be landed with their fins attached and the prohibition for the retention of thresher sharks. The Shark Fisheries Management Regulation of 2015 also prohibits the retention of oceanic white tip sharks, requires the recording of shark catches/discards in logbooks, among other things (Hewapathirana et al. 2018). 

Large longline vessels generally catch older age classes of bigeye tuna (Thunnus obesus_) and bluefin tunas (_T. maccoyii [southern], T. orientalis [Pacific] and T. thynnus [Atlantic]) for the sashimi market and some longline fleets target albacore (T. alalunga_) for canning. Purse seine vessels target younger age classes of skipjack (Katsuwonus pelamis_) and yellowfin (T. albacares) tuna for canning with incidental catch of bigeye tuna. Smaller swordfish are often discarded in pelagic longline tuna fisheries due to minimum size requirements or low market value (Cramer, 2003; Wardet al., 2008).

Thai tuna longliners do not record shark by-catch from their operations in the Indian Ocean. By-catch study by Thai Dept. of Fisheries Research vessel showed that blacktip sharks, blue sharks, crocodile sharks, silky sharks, blue marlins, dolphin fish and sting rays were caught by longliners operating in the Indian Ocean. Other species reported included Great barracuda, Lancet fish, sickel pomfret, snake mackerel, swordfish and wahoo (Saikliang and Nootmorn 2011).

The Indonesian yellowfin tuna handline fishery is a pelagic fishery, which operate in deep oceanic waters and do not interact with the seabed. Negligible habitats impacts would therefore be anticipated (Moody Marine LTD 2010); (Hough 2018)).  However, the fishery uses anchored fishing aggregation devices (FADs), which the MSC recognizes as habitat modifications (Hough 2018). The extent to which this fishery contributes chemical pollution or derelict fishing gear into oceanic pelagic habitats operates is unknown but warrants review.

Pelagic gear does not come in direct contact with the seafloor.Lost and discarded gear can damage coastal habitats.

Last updated on 17 Feb 2011

There are 35 marine conservation areas (protected areas) in Indonesia by 2002, totaling 47 thousand km2. Compared to Indonesia’s total marine territory of 7.9 million km2 (including the Exclusive Economic Zone), this is far from sufficient. Many of these protected areas include mangrove forests, the spawning grounds for shrimp and other marine biotas.

IOTC established a one month per year closure to longline and purse seine vessels of an area off Somalia, which is in effect from 2011 to 2012, in an attempt to reduce mortality of small and juvenile tunas (IOTC, 2010a).

The impact on marine habitats in longlining is far less than that of seafloor trawling or dredging. With longline gear, juvenile or unwanted fish can be identified and returned to the sea, very often unharmed depending on the species. However, due to the length of time fish remain on the hook, many are inadvertently killed. Strict regulation and scientific observation are the most important steps towards ecological sustainability no matter what the fishing method.

Last updated on 19 Apr 2010

There are 35 marine conservation areas (protected areas) in Indonesia by 2002, totaling 47 thousand km². Compared to Indonesia’s total marine territory of 7.9 million km² (including the Exclusive Economic Zone), this is far from sufficient. Many of these protected areas include mangrove forests, the spawning grounds for shrimp and other marine biotas.

The impact on marine habitats in longlining is far less than that of seafloor trawling or dredging. With longline gear, juvenile or unwanted fish can be identified and returned to the sea, very often unharmed depending on the species. However, due to the length of time fish remain on the hook, many are inadvertently killed. Strict regulation and scientific observation are the most important steps towards ecological sustainability no matter what the fishing method.

Last updated on 19 Apr 2010

There are 35 marine conservation areas (protected areas) in Indonesia by 2002, totaling 47 thousand km². Compared to Indonesia’s total marine territory of 7.9 million km² (including the Exclusive Economic Zone), this is far from sufficient. Many of these protected areas include mangrove forests, the spawning grounds for shrimp and other marine biotas.

The fishery is conducted in pelagic waters targeting surface swimming stocks and stocks surrounding FADS.
Baitfish fishery in Maldives is reported to have caused substantial damage to reefs in the past (Anderson and Saleem 1995), although there is no evidence to state that such practices continue today. More recent data on bait fish collection shows that it is collected using lights at night.

In general, primary gear used to catch yellowfin tuna, do not come in direct contact with the seafloor.

According to MFAR (2007), degradation of the coastal and marine environment which includes coastal pollution and the threats to the sustainability of coastal habitats has emerged as a major problem adversely affecting the fishing industry (MFAR 2007).However, no specific information found regarding to the impact of yellowfin tuna fisheries to the habitat in Sri Lanka.

Last updated on 05 Dec 2009

The Sri Lankan Coast Conservation Act No 57 of 1981 (and its amendments, 1988) provide the legal foundation for activities within the coastal zone. As mandated by the Act, the Coastal Conservation Department developed a Coastal Zone Management Plan (CZMP) for the management of the coastal zone and this document is updated every five years. Special Area Management (SAM) is managing sites of special significance and public access, regulatory mechanisms, and integrating coastal fisheries aquaculture with coastal zone management. SAM actions articulated under the CZMP include the management of MCPAs.

Currently, there are 13 MCPAs in Sri Lanka, covering area of 314,754 ha. Within this list, there are only 2 Marine Sanctuaries, namely Bar Reef (30,670 ha) and Rumassala (1,707 ha). See: List of MCPAs .

In general, primary gear used to catch yellowfin tuna, including purse seine, pelagic longline and pole-and-line gear, do not come in direct contact with the seafloor. Lost and discarded gillnet gear can damage coastal habitats.

Last updated on 22 Jun 2012

To ease pressure on juvenile and small tunas, IOTC has adopted a one month per year closure to longline and purse seine vessels of an area off Somalia is in effect from 2011 to 2012. Several coastal States also have time/area closures in domestic waters (e.g., Sri Lanka).

Fisheries that target high-level predators such as tunas will have some impact on marine ecosystems. Some research has suggested that exploitation by tuna fisheries can alter both target populations and a diversity of other species in the affected ecosystems ((Hinke et al. 2004); see (Schindler et al. 2002), for review); however, there is little empirical evidence for top-down control in oceanic ecosystems such as the Indian Ocean (Baum and Myers 2009). In addition, the Indonesian yellowfin handline fishery in the Indian Ocean uses fishing aggregation devices (FADs), which the MSC recognizes as habitat modifications and could entrain tuna and other species, including ETP species (Hough 2018). It is unclear what effects these FADs might have on Indian Ocean ecosystems.

In addition, the handline fishery catches its own bait (Hough 2018). Large quantities of baitfish are needed to support productive hook and line tuna fisheries; depending on the type and source of these baitfish, required quantities might not be possible or sustainable (Gillett 2011). Thus, baitfish harvest for longline tuna fishing operations could affect pelagic ecosystems as well.

Although some studies have included the North Central Pacific, Central Pacific, and Eastern Tropical Pacific (Schindler et al. 2002); (Baum and Myers 2009)) and have suggested mesopredator and prey releases when predatory tuna species are overexploited, no studies – either empirically derived or model-based – have examined potential ecosystem effects specifically in the Indian Ocean.

Fisheries that target high-level predators such as tunas will have some impact on marine ecosystems. Some research has suggested that exploitation by tuna fisheries can alter both target populations and a diversity of other species in the affected ecosystems (Hinke et al. 2004; see Schindler et al., 2002, for review); however, there is little empirical evidence for top-down control in oceanic ecosystems such as the Indian Ocean (Baum and Myers 2009). 

In general, if a tuna fishery maintains target catch at or below MSY, it is not expected to have top-down ecosystem impacts. Both bigeye and yellowfin tuna are current at or below MSY (Collinson and Gascoigne 2015). Although some studies have included the North Central Pacific, Central Pacific, and Eastern Tropical Pacific ((Schindler et al. 2002); (Baum and Myers 2009)) and have suggested mesopredator and prey releases when predatory tuna species are overexploited, no studies – either empirically derived or model-based – have examined potential ecosystem effects in the Indian Ocean longline tuna fisheries.

Large quantities of baitfish are needed to support productive hook and line tuna fisheries; depending on the type and source of these baitfish, required quantities might not be possible or sustainable (Gillett 2011). Thus, baitfish harvest for longline tuna fishing operations could affect pelagic ecosystems as well.

Although some studies have included the North Central Pacific, Central Pacific, and Eastern Tropical Pacific ((Schindler et al. 2002); (Baum and Myers 2009)) and have suggested mesopredator and prey releases when predatory tuna species are overexploited, no studies – either empirically derived or model-based – have examined potential ecosystem effects specifically in the Indian Ocean.