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Profile updated on 5 September 2019

SUMMARY

SUMMARY

IDENTIFICATION

SCIENTIFIC NAME(s)

Katsuwonus pelamis

SPECIES NAME(s)

Skipjack tuna

It is likely that skipjack are distributed throughout the Pacific as a single population. Exchange of fish between the eastern and western region is not common. The majority of catches occur in the eastern and western regions. Therefore assessments are conducted for both the eastern and western regions (Maunder 2015).


ANALYSIS

Strengths
  • Fishing mortality rates and biomass are currently thought to be sustainable.
  • Discarding of tunas is prohibited.
  • There is a multi-year conservation plan in place, which has just been extended, for skipjack tuna (and other tuna species).
  • A harvest control rule has been adopted.
  • There is 100% observer coverage on large purse seine vessels operating on the high seas.
  • Biomass and recruitment have been increasing over the past 20 years and were above their respective upper reference levels in 2016 and 2017.
  • Independently from the IATTC, Ecuador is capable of developing its own control and surveillance measures within its EEZ and at port.
  • There are measures established by the Ecuadorian government in order to prevent negative impacts of this fishery on vulnerable species such as shark and dolphins.
Weaknesses
  • There are no MSY based reference points used for skipjack tuna in the EPO.
  • There are time/area closures in place for the purse seine fleet but these measures are not sufficient to manage the fish aggregating device (FAD) fishery.
  • Purse seine fisheries can interact with ETP species..
  • There is a significant lack of catch data coming from the Ecuadorian longline fleet. The observer program does not cover a significant sample of longline vessels and it is mainly implemented for purse-seine vessels.
  • At the current level of available data from the fishery, it is not possible to conduct a comprehensive biological assessment aimed at the abundance and fishing mortality.
  • There is virtually no scientific knowledge regarding the effects of longlines on the species and its interaction within the eastern Pacific Ocean ecosystem.
  • Longlines may have negative interactions with endangered, threatened and protected (ETP) species, and information on these interactions and its current impact it's scarce in Ecuador.
Options
  • To enforce the monitoring, control and surveillance system for the longline fleet, implementing wider the observer program and taking in situ accurate data regarding the fleet operation as fishing effort, grounds, discards and ETP-species interaction.
  • From the INP, to boost the biological assessments within their boundaries; to develop independently target reference points for this species with comprehensive control and to work jointly with the IATTC to get the most accurate data for a stock assessment.

FISHSOURCE SCORES

Management Quality:

Management Strategy:

≥ 6

Managers Compliance:

≥ 6

Fishers Compliance:

≥ 6

Stock Health:

Current
Health:

≥ 8

Future Health:

≥ 8


RECOMMENDATIONS

RETAILERS & SUPPLY CHAIN
  • Work with IATTC Members and Cooperating Non-Members to:
    • Adopt purse seine set limits.
    • Develop and implement comprehensive, precautionary harvest strategies with specific timelines for all tuna stocks, including the adoption and implementation of limit and target reference points, harvest control rules, monitoring strategies, operational objectives, performance indicators, and management strategy evaluation.
    • Strengthen compliance processes and make information on non-compliance public and continue to provide evidence of compliance with all IATTC Conservation and Management Measures in a timely manner.
    • Implement a 100% observer coverage requirement for at-sea transshipment activities, as well as other measures that ensure transshipment activity is transparent and well-managed, and that all required data are collected and transmitted to the appropriate bodies in a timely manner.
    • Increase compliance with the mandatory minimum 5% longline observer coverage rates by identifying and correcting non-compliance.
    • Implement a 100% observer coverage requirement – human and/or electronic – within five years for longline fisheries. Adopt a 100% observer coverage requirement for purse seine vessels where it is not already required and require the use of the best-available observer safety equipment, communications and procedures.
    • Adopt effective measures for the use of non-entangling FAD designs as a precautionary measure to minimize the entanglement of sharks and other non-target species, and support research on biodegradable materials and transition to their use to mitigate marine debris. 
    • More effectively implement, and ensure compliance with, existing RFMO bycatch requirements and take additional mitigation action, such as improving monitoring at sea, collecting and sharing operational-level, species-specific data, and adopting stronger compliance measures, including consequences for non-compliance for all gear types.
  • Ensure all products are traceable back to legal sources. Verify source information and full chain traceability through traceability desk audits or third party traceability certification. For fisheries without robust traceability systems in place, invest in meaningful improvements to bring the fisheries and supply chain in compliance with best practices.

FIPS

No related FIPs

CERTIFICATIONS

No related MSC fisheries

Fisheries

Within FishSource, the term "fishery" is used to indicate each unique combination of a flag country with a fishing gear, operating within a particular management unit, upon a resource. That resource may have a known biological stock structure and/or may be assessed at another level for practical or jurisdictional reasons. A fishery is the finest scale of resolution captured in FishSource profiles, as it is generally the scale at which sustainability can most fairly and practically be evaluated.

ASSESSMENT UNIT MANAGEMENT UNIT FLAG COUNTRY FISHING GEAR
Eastern Pacific Ocean IATTC Colombia Associated purse seining
FAD-free
Ecuador Dolphin set purse seining
FAD-free
Longlines
Purse seines
Mexico Dolphin set purse seining
FAD-free
Pole-lines hand operated
Purse seines
Nicaragua Associated purse seining
FAD-free
Panama Associated purse seining
FAD-free
Spain FAD-free
Purse seines
United States Associated purse seining
Drifting longlines
Venezuela, Bolivarian Republic of Associated purse seining

Analysis

OVERVIEW

Last updated on 5 September 2019

Strengths
  • Fishing mortality rates and biomass are currently thought to be sustainable.
  • Discarding of tunas is prohibited.
  • There is a multi-year conservation plan in place, which has just been extended, for skipjack tuna (and other tuna species).
  • A harvest control rule has been adopted.
  • There is 100% observer coverage on large purse seine vessels operating on the high seas.
IATTC
Ecuador
Longlines

Last updated on 5 September 2019

  • Biomass and recruitment have been increasing over the past 20 years and were above their respective upper reference levels in 2016 and 2017.
  • Independently from the IATTC, Ecuador is capable of developing its own control and surveillance measures within its EEZ and at port.
  • There are measures established by the Ecuadorian government in order to prevent negative impacts of this fishery on vulnerable species such as shark and dolphins.
Weaknesses
  • There are no MSY based reference points used for skipjack tuna in the EPO.
  • There are time/area closures in place for the purse seine fleet but these measures are not sufficient to manage the fish aggregating device (FAD) fishery.
  • Purse seine fisheries can interact with ETP species..
IATTC
Ecuador
Longlines

Last updated on 5 September 2019

  • There is a significant lack of catch data coming from the Ecuadorian longline fleet. The observer program does not cover a significant sample of longline vessels and it is mainly implemented for purse-seine vessels.
  • At the current level of available data from the fishery, it is not possible to conduct a comprehensive biological assessment aimed at the abundance and fishing mortality.
  • There is virtually no scientific knowledge regarding the effects of longlines on the species and its interaction within the eastern Pacific Ocean ecosystem.
  • Longlines may have negative interactions with endangered, threatened and protected (ETP) species, and information on these interactions and its current impact it's scarce in Ecuador.
Options
IATTC
Ecuador
Longlines

Last updated on 5 September 2019

  • To enforce the monitoring, control and surveillance system for the longline fleet, implementing wider the observer program and taking in situ accurate data regarding the fleet operation as fishing effort, grounds, discards and ETP-species interaction.
  • From the INP, to boost the biological assessments within their boundaries; to develop independently target reference points for this species with comprehensive control and to work jointly with the IATTC to get the most accurate data for a stock assessment.
RECOMMENDATIONS

Last updated on 31 July 2019

Recommendations to Retailers & Supply Chain
  • Work with IATTC Members and Cooperating Non-Members to:
    • Adopt purse seine set limits.
    • Develop and implement comprehensive, precautionary harvest strategies with specific timelines for all tuna stocks, including the adoption and implementation of limit and target reference points, harvest control rules, monitoring strategies, operational objectives, performance indicators, and management strategy evaluation.
    • Strengthen compliance processes and make information on non-compliance public and continue to provide evidence of compliance with all IATTC Conservation and Management Measures in a timely manner.
    • Implement a 100% observer coverage requirement for at-sea transshipment activities, as well as other measures that ensure transshipment activity is transparent and well-managed, and that all required data are collected and transmitted to the appropriate bodies in a timely manner.
    • Increase compliance with the mandatory minimum 5% longline observer coverage rates by identifying and correcting non-compliance.
    • Implement a 100% observer coverage requirement – human and/or electronic – within five years for longline fisheries. Adopt a 100% observer coverage requirement for purse seine vessels where it is not already required and require the use of the best-available observer safety equipment, communications and procedures.
    • Adopt effective measures for the use of non-entangling FAD designs as a precautionary measure to minimize the entanglement of sharks and other non-target species, and support research on biodegradable materials and transition to their use to mitigate marine debris. 
    • More effectively implement, and ensure compliance with, existing RFMO bycatch requirements and take additional mitigation action, such as improving monitoring at sea, collecting and sharing operational-level, species-specific data, and adopting stronger compliance measures, including consequences for non-compliance for all gear types.
  • Ensure all products are traceable back to legal sources. Verify source information and full chain traceability through traceability desk audits or third party traceability certification. For fisheries without robust traceability systems in place, invest in meaningful improvements to bring the fisheries and supply chain in compliance with best practices.

1.STOCK STATUS

STOCK ASSESSMENT

Last updated on 16 August 2018

Stock assessments are difficult to conduct on skipjack tuna due to their high and variable productivity. These characteristics make it difficult to determine the effect of fishing using typical stock assessment techniques. The Inter-American Tropical Tuna Commission (IATTC) conducts assessments of skipjack tuna using various indicators instead of traditional reference points. The most recent assessment conducted in 2018 used eight data and model based indicators 1) catch, 2) CPDF NOA, 3) average weight, 4) relative recruitment, 5) CPDF OBJ, 6) standardized effort, 7) relative biomass, and 8) exploitation rate (Maunder 2018).

SCIENTIFIC ADVICE

Last updated on 16 August 2018

The latest scientific advice, based on the 2015 assessment, is that there is no concern over the status of the stock and no additional management measures beyond those adopted for other tropical tuna species are needed (IATTC 2018)(Maunder 2018).

 
CURRENT STATUS

Last updated on 16 August 2018

It is most likely that skipjack tuna are not overfished or undergoing overfishing (Maunder 2018).

Trends

The biomass, recruitment and exploitation rates have been variable over time. In recent years the biomass has been above average levels but this varies among regions of the eastern Pacific Ocean. Fishing mortality rates were higher during the 1970’s and early 1980’s and has fluctuated around average levels since the mid-1990's (Maunder 2018).

2.MANAGEMENT QUALITY

MANAGEMENT

Last updated on 16 August 2018

The Inter-American Tropical Tuna Commission (IATTC) currently has a multi-year conservation plan in place for bigeye, skipjack and yellowfin tuna caught in the eastern Pacific Ocean. Management measures specific to the purse seine fisheries include a mandatory closure for 72 days during one of two predefined time periods and there is an additional purse seine closure between October 9th and November 8th in the area of 960 and 1100W and between 40N and 30S (IATTC 2017). If a fisheries observer is onboard from the On-Board Observer Program of the Agreement on the International Dolphin Conservation Program (AIDCP), the vessels (182-272 metric tons carrying capacity) can make one 30 day trip during the specified closures dates. An additional time/area closure off the coast of Central and South America for purse seine vessels is also in place (IATTC 2017). Discarding bigeye, skipjack and yellowfin tuna is prohibited {IATTC 2013}. Purse seine vessels are also prohibited from setting on data buoys {IATTC 2010}.

IATTC has a multi-annual conservation program in place to monitor tuna populations. The plan was last updated in 2017 for the 2018-2020 fishing seasons (IATTC 2017).

IATTC
Ecuador
Longlines

Last updated on 5 September 2019

According to the Inter-American Tropical Tuna Commission (IATTC) it is likely that there is a continuous single population throughout the Pacific Ocean, with an exchange of individuals at a local level (IATTC 2018). Within Ecuador, the Instituto Nacional de Pesca (INP) is the official scientific body in charge of assessing the marine resources and then for advising and providing the recommended management measures to the Viceministerio de Acuacultura y Pesca. The IATTC is the entity which assess, regulates and manages tuna species in the Eastern Pacific Ocean, Ecuador is part of this agreement and responds to the resolutions adopted by this body. Ecuador participates in the IATTC process by providing statistical information from its fleet.

The current IATTC management plan for the period 2018-2020 has been established by the resolution C-17-02 (IATTC 2017). The measures developed here, apply to all longline vessels over 24 meters length overall that fish for yellowfin tuna, bigeye tuna, and skipjack tuna. These vessels are considered an industrial large-scale fleet (known as LSTLFVs) and according to the IATTC vessel database (available at: https://www.iattc.org/VesselDataBaseENG.htm), there are currently 20 Ecuadorian flag vessels registered to operate in the Convention area with a fish-holding capacity that ranges from 57 m³ up to 589 m³.  Ecuador submits an annual report to IATTC which contains information from this longline fleet such as the total capture and its composition, interaction with other species (non-target and ETP species) and fishing effort; in the period between January 2017 to September 2017 the coverage of observers in the fleet was about 10% of the total effort estimated in fishing days. It is important to mention that the IATTC has calculated that the minimum and sufficient level of coverage on longline vessels to produce reliable estimates of the species caught is 20% although its resolution C-11-08 (IATTC 2011) establishes a mandatory coverage of 5% of the fishing effort by a scientific observer. Few skipjack are captured by the longline fleet, thus this fishery cannot be used to elaborate reliable index of abundance for this species (IATTC 2018)

Ecuador, through the Acuerdo Ministerial N° 407 (Ministerio de Agricultura, Ganadería, Acuacultura y Pesca 2011) defines a ‘nodriza’ as a vessel that tows up to ten smaller artisanal longline vessels or ‘fibras’ towards far fishing grounds and its purpose is to supply water, fuel, food, bait and other supplies for fishing, and also to receive the catch from the small vessels. Amongst the requirements needed for the fishing, there is an ‘official agreement’ grant by the Subsecretaría de Recursos Pesqueros, a fishing permit which has to be annually renovated, certificates of the ship, a vessel monitoring system and a sanitary permit.

Within the Ecuadorian framework, seasonal closures have not been found for its longline fleet, probably due to the fact that neither the IATTC apply them. The Acuerdo Ministerial N° 407 (Ministerio de Agricultura, Ganadería, Acuacultura y Pesca 2011) states that the Subsecretaría de Recursos Pesqueros has the responsibility of setting an observer program covering 10% of the artisanal ‘nodriza’ fleet.  Nevertheless, specific and technical aspects like the fishing gear interaction with other species and catch per unit of effort in longlines is not being taken, this generates a void in data and potential management. Another measure taking in Ecuador by some tuna companies is the implementation of a Fisheries Improvement Project (FIP) aimed at getting the sustainability standard of the Marine Stewardship Council (MSC), and as result of this, there is a current process to design the National Plan of Action for the sustainable management of the industrial fishery for the Ecuadorian Tuna (PAN-Atún) FIP, led by the Viceministerio de Acuacultura y Pesca through a participatory process that involves key players in the value chain of this fishery.

COMPLIANCE

Last updated on 16 August 2018

There is no TAC in place for skipjack tuna.

IATTC
Ecuador
Longlines

Last updated on 5 September 2019

Through the publication of the Acuerdo Ministerial No. MAGAP-MAGAP-2015-001-A,(Ministerio de Agricultura, Ganadería, Acuacultura y Pesca 2015) the national action plan to prevent, discourage and eliminate illegal, unreported and unregulated fishing came into effect (PAN-INDNR, in Spanish). The Control and Monitoring System (SCM, in Spanish), set by the Subsecretaría de Recursos Pesqueros of Ecuador, gathers data from the Ecuadorian artisanal fleet in the main artisanal landing ports. This artisanal fleet comprises an artisanal-oceanic component that consists in large vessels called ‘nodrizas’ which tow smaller fiberglass vessels (called ‘fibras’) which operate mainly with pelagic longlines off 200 miles from the coast. It has been estimated that ‘Nodrizas’ represent up to 80% of the total artisanal capture (Martínez-Ortiz et al. 2015).

According to IATTC (2017), just small amounts of skipjack are captured by longlines. The IATTC registers the information of all the vessels authorized to operate in the Eastern Pacific Ocean, but it is recognized that this list is incomplete (IATTC 2018) particularly regarding the large longline fleet and small vessels. Ecuador through the INP gathers and presents some biological data from the large-scale longline fleet. Information about capture and characterization of artisanal longline fleets have been shown in studies conducted by INP staff. In addition, it should be mentioned that regarding the longline capture, the IATTC maintains data about the spatial and temporal distribution of longline captures by countries. Data from the industrial longline fleet is taken by IATTC observers in collaboration with the INP with a coverage of approximately 10% of the fishing effort, in comparison with the minimum 5% set by the IATTC resolution C-11-08 (IATTC 2011). Discarding cannot be estimated with accuracy for the artisanal longline fleet, one reason might be the coverage of the observer program onboard in port, inspectors monitor the landing and assess the reliability of the data recorded in the captain’s logbook. A monitoring certificate is generated and delivered during the landing (Martínez-Ortiz et al. 2015) Such verified logbook records provide trip-by-trip catch composition data ( in numbers of fish and weight), as well as effort information (number of hooks per set, days fished, numbers of individual smaller boats operating from the mother-ship) (Martínez-Ortiz et al. 2015).

3.ENVIRONMENT AND BIODIVERSITY

BYCATCH
ETP Species

Last updated on 16 August 2018

Purse seine fisheries have some interactions with sea turtles, but far less than in the longline fisheries and marine mammal interactions are minimal. The troll and pole fisheries for bigeye tuna do not incidentally capture any of these species.The Inter-American Tropical Tuna Commission (IATTC) has put several management measures aimed at bycatch species into place. Shark finning is banned (5% rule) and oceanic whitetip sharks are prohibited from being retained (IATTC 2011b)(IATTC 2011c)(IATTC 2005)(IAC 2012). Purse seine fisheries fishing on fish aggregating devices (FADs) must use specific methods designed to avoid entangling sea turtles or other bycatch species. Any interactions must be reported and sea turtles are to be released (IATTC 2012)(IATTC 2007).

IATTC
Ecuador
Longlines

Last updated on 5 September 2019

There are few estimations regarding the incidental catch of marine turtles by longlines in Ecuador. The incidental catch of turtles associated with the industrial longline fleet in the Eastern Pacific Ocean targeting Bigeye tuna is probably lesser at greater depths (200-300m) (IATTC 2018) and occurs when they take the bait on the hooks, when they accidentally get hooked or entangled in lines (IATTC 2018), (IATTC 2018). Mortality data on the interactions between the longline fishery and turtles is deficient in the Eastern Pacific Ocean (IATTC 2018). For Ecuadorian longline fisheries participatory programs have been developed which involve the voluntary testing of circle hooks to reduce the mortality of sea turtles  (Andraka et al. 2013); (Gilman et al. 2006) and other activities such as training of fishers in on-board sea turtle handling techniques to improve the survival of the turtles released after hooking or entanglement (Andraka et al. 2013). Loggerhead and leatherback turtles are the primary species caught in the pelagic longline gear and olive ridley, hawsbill (Eretmochelys imbricata) and Kemp's ridely (Lepidochelys kempii) turtles are also captured (Gilman et al. 2006). According to the observer program in the large-scale longline fleet, in 2017 Ecuador reported to the IATTC incidental captures of green turtle (Chelonia mydas) and olive ridley turtle (Lepidochelys olivacea) Andraka et al. (2013) described the interaction of the olive ridley turtle (Lepidochelys olivacea) with the artisanal longline fleet in the eastern Pacific Ocean.

Regarding shark and rays species, IATTC (2018a2018b) registered interactions of longlines with the silky shark (Carcharhinus falciformis), the oceanic whitetip shark (Carcharhinus longimanus), hammerheads (Sphyrna spp.), threshers (Alopias spp.) and mako (Isurus spp) sharks. Further information regarding shark interactions with the Ecuadorian longline fleet targeting tuna is scarce but two studies do exist. The first one conducted by the INP (Pacheco 2010) on a Spanish longline fleet associated with Ecuador targeting tuna and other species, which registered the capture of shortfin mako (Isurus oxyrinchus), smooth hammerhead (Sphyrna zygaena), blue shark (Prionace glauca) and bigeye thresher (Alopias superciliosus) and leatherback turtle (Dermochelys coriacea). The second one, conducted by Martínez-Ortiz et al. (Martínez-Ortiz et al. 2015), states that shark catch by longline gear are largely dominated by the thresher shark group, then the pelagic thresher and blue and silky sharks make up the second dominant group. Furthermore, IATTC (IATTC 2018) states that sharks are captured as incidental catch in the longline fishery within the Eastern Pacific Ocean. Ecuadorian national framework has established measures to reduce the impact of longlines on sharks, which are contained in the Decreto N° 486, the N° 902 and the Plan Acción de Tiburones (PAT-Ec), which establish the conservation and management of sharks as national priority, forbidding the target of sharks and specialized fishing gear adaptations.

On the other hand, there were no interactions with birds or mammals. Some endemic bird species are of special concern like the Albatross de Galápagos (Phoesbastriairrorata) but any registers of the albatross interaction with the Ecuadorian longline fleet has not been found.

Other Species

Last updated on 1 November 2014

In the purse seine fishery (floating object), yellowtail, mahimahi, rainbow runner and wahoo are common bycatch species. Mahimahi and rainbow runner are also caught in the unassociated fisheries. Assessments have not been conducted on these species, so their status is unknown. Silky and oceanic white tips sharks, along with manta rays (unassociated) are also incidentally caught (Hall and Rowman 2013). No assessments of oceanic whitetip sharks or manta rays have been conducted. Oceanic whitetip sharks are prohibited from being retained and shark finning (5% rule) is prohibited (IATTC 2011c).

IATTC
Ecuador
Longlines

Last updated on 5 September 2019

It's unlikely, at least in the near future, to obtain the assessment of all the populations of the largest part of species which conforms the bycatch (IATTC 2018). The composition of non-target species registered from the artisanal fleet (INP, 2017) describes that the skipjack tuna can be found along with the bigeye tuna and wahoo (Acanthocybium solandri), the Pacific sierra (Scomberomorus sierra). In more detail to Scombridae, longline catches by the artisanal fleet are dominated by the yellowfin tuna, the bigeye tuna and also the swordfish (Xiphias gladus) represents an important amount of the catches (Martínez-Ortiz et al. 2015). Andraka et al. (2013) points as important bycatch species for this fishery yellowfin tuna (Thunnus albacares), mahi mahi (Coryphaena hippurus), skipjack tuna (Katsuwonus pelamis), swordfish (Xiphias gladus) , sailfish (Istiophorus platypterus) and black marlin (Istiompax indica). The current stock status and impact of the fishery on species like. Mahi mahi (Coryphaena hippurs) or black marlin is still difficult to predict in some cases because of the lack of reliable data. Probably one important boost in the long-term for one of this species (mahi mahi), is the current assessment of its fishery in Ecuador against the Marine Stewardship Council standard which could help at some extent to quantify properly the accumulated impact on this species.

Estimated target reference points or normative focused on controlling the capture and landings of the other bycatch species have not been found and a relative population analysis might be conducted from more accurate and reliable capture and effort data.

HABITAT

Last updated on 23 September 2012

The gears used to capture tuna have no impact on bottom habitats.

Marine Reserves

Last updated on 23 Sep 2012

All tuna purse seiners operating in the Eastern Pacific Ocean were required to stop fishing for a period of 62 days in 2011 and 2012 (IATTC 2012). The closures were in effect for the following time periods.

2011 – 29 July to 28 September, or from 18 November to 18 January 2012.
2012 – 29 July to 28 September, or from 18 November to 18 January 2013.
2013 – 29 July to 28 September, or from 18 November to 18 January 2014.

IATTC
Ecuador
Longlines

Last updated on 5 September 2019

Skipjack tuna inhabits the epipelagic zone of the world's major oceans and apparently only make forages into deeper zones (Baldnge and Byrne n.d.). They are distributed across the Pacific in tropical and sub-tropical latitudes, usually in waters exceeding 20°C (Bayliff 1980). Specifically, in the eastern Pacific, they occur commonly from 30°N to about 30°S (Brock, 1959; Kearney, 1978, in Bayliff 1980). Larvae have been found over a wide area in all the major oceans, in particular, in the eastern Pacific from 15°N to 5°S (Klawe 1963; Love 1970, 1971, 1972, 1074, in Baldnge and Byrne n.d.). Its distribution in the Pacific is narrow in the east due to the constriction of warm water favorable for spawning by cold currents flowing toward the Equator in both hemisphere’s (Baldnge and Byrne n.d.). Matsumoto (1975 in  Baldnge and Byrne n.d.) reported that the center of larval skipjack tuna abundance was between 160°E and 140°W. Northward and southward limits vary seasonally and annually as the skipjack tuna respond to seasonal changes in the environment (Baldnge and Byrne n.d.). Surface currents affect the distribution of larvae and adults of skipjack tuna, the flow toward the Equator of cool water on the eastern side of the oceans tends to restrict the distribution of fish in that region, further, in currents flowing meridional, tuna are considered to be distributed along the axis of the current and in greater abundance than in adjacent waters (Baldnge and Byrne n.d.). Fishing by longliners is widespread throughout the western and central Pacific, but in the eastern Pacific, it is less intense and occurs only in some areas. Although few skipjack are captured by longline, occurrences indicate the range of the larger adults is in the western and central Pacific. Skipjack have been fished along the west coast of the Americas from 34°N off southern California to 27°S off northern Chile (Bayliff 1980). Usually larvae are above the thermocline (Bayliff 1980) whereas for adults in the eastern Pacific, few authors have shown that fishable concentrations occasionally were found as low as 17°C and as high as 30°C, but usually found between 20°C - 28°C.

It is considered that a negative interaction between the habitat and longlines is not likely to happen, mainly due to the passive nature of the fishing gear, due to the shallowness of the resource with the consecutive use of surface longlines and also because the fleet size is nor representative. Unlike some other gear types, pelagic longlines do not touch the seafloor and do not directly damage to habitat (Gilman et al. 2006). Nevertheless, it is necessary to conduct further researches in order to know the real impact of longlines. It is not considered to be robust information to identify location, timing, and severity of the longline fleet in the habitats due to the coverage of the surveillance and monitoring system and whether there is an impact is still unclear.

ECOSYSTEM
IATTC
Ecuador
Longlines

Last updated on 5 September 2019

Based on studies of tuna longline catches, Yabe et al. (1963) indicated that tunas are distributed by depth layers with the skipjack tuna occupying the shallowest layer, this was assumed largely on the basis that they are taken in commercial quantities almost entirely by fishing gear that requires the fish to be at or very near the surface, and that the skipjack tuna are taken only incidentally on the deep-fishing longline (Matsumoto et al., n.d in Baldnge and Byrne n.d.). Some observations on feeding aggregations for skipjack tuna has shown as probable competitors the yellowfin tuna (Thunnus albacares); albacore (Thunnus alalunga); kawakawa, frigate tuna (Auxis thazard), dolphins and whale shark (Rhincodon typus) (Gudger 1941; Waldron 1963, in Baldnge and Byrne n.d.), this species  as well as sea birds might be at some point exposed to the effects of longlines but this not very likely to happen since other fishing gears are preferred for this species

The IATTC (IATTC 2018) has conducted research on the eastern Pacific Ocean ecosystem using trophic levels (TL) to characterize the energy fluxes through the different communities. In this case, the average trophic level of capture (MTLc) can be a useful metric of change and sustainability of the ecosystem integrating a variety of biological data regarding the components of the system and several MTL are calculated in relation to the TL  It's also an indicator of whether fisheries are changing their fishing practices These indicators point to the fact that ecosystem structure has probably changed, however, if this is a direct result from fisheries, they are not considered ecologically harmful (IATTC 2018). No studies about the ecosystem state of reference, the effect of fishing and its dynamics has been done by the Ecuadorian scientific advisory body, mostly this analysis falls on the IATTC.

FishSource Scores

Last updated on 9 September 2019

MANAGEMENT QUALITY

As calculated for 2019 data.

The score is ≥ 6.

There are no specific and explicit management objectives for the species and there are no target reference points due to a comprehensive biological assessment by INP.

As calculated for 2019 data.

The score is ≥ 6.

Manager’s take key recommendations from the scientific body, and Ecuadorian framework recognizes the application of the IATTC resolutions.

As calculated for 2019 data.

The score is ≥ 6.

The accurate magnitude of IUU and discards cannot be completely quantified for the longline fishery. However skipjack is not commonly targeted by this gear.

STOCK HEALTH:

As calculated for 2018 data.

The score is ≥ 8.

The biomass is likely above MSY levels

As calculated for 2018 data.

The score is ≥ 8.

Fishing mortality rates are likely below MSY levels

ECOSYSTEM IMPACTS

Click on the score to see subscore

Click on the score to see subscore

Click on the score to see subscore

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Bycatch Subscores

Some reliable and general information is gathered. The observers program do not have an entire coverage and representativeness of the  longline fleet (Ministerio de Agricultura, Ganadería, Acuacultura y Pesca 2011) and/or this information is not available. Some important data can be inferred from the landings data but this excludes potential discards that might be occurring at sea.

Some shark species considered as ETP species are still captured by this fishery and without a TAC established.(Gómez 2016; IATTC 2018; IATTC 2018; Martínez-Ortiz et al. 2015; Pacheco 2010) Longline interaction may jeopardize the ETP species populations.

Most of bycatch species do not have reference points set and the current status of their populations is unknown (IATTC 2018)(IATTC 2018). Data is not abundant but it is likely that the fishery may impact a population.

There are generic measures tailored for avoiding sharks capture (gear and hook restrictions) (Correa 2008)(Correa 2008) and marine turtles.

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Habitat Subscores

There is general information regarding the impact of longlines in marine habitats.

There is some information available regarding the location and timing of the fishing.

Since longlines are set near the surface or mid-waters, impacts on the bottom are minimal

The species distribution and some environmental requirements in the eastern Pacific have been mapped.(Baldnge and Byrne n.d.; Bayliff 1980; Hu et al. 2018)

Since this fishing gear interacts passively with the marine environment, it is unlikely that longlines would interact negatively or hinder the structure and function of the habitat.

No measures in place to avoid the potential damage of longlines in habitats were found within the Ecuadorian framework.

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Ecosystem Subscores

There is biological information used by RFMOs to describe the impact of the tuna species fishery

There is comprehensive information about the distribution, behavior and interaction of this species  within the ecosystem which permits to set state references. (Baldnge and Byrne n.d.;IATTC 2018; IATTC 2018)

Some impact is measurable through the use of trophic indicators and a comprehensive data gathering by the IATTC.

No measures in place were found.

To see data for biomass, please view this site on a desktop.
To see data for catch and tac, please view this site on a desktop.
To see data for fishing mortality, please view this site on a desktop.
No data available for recruitment
No data available for recruitment
To see data for management quality, please view this site on a desktop.
To see data for stock status, please view this site on a desktop.
DATA NOTES

1. We are aware of no advised or set quotas/TAC thus qualitative scores have been computed for 1, 2 and 3. 2. Indicators are currently used instead of traditional MSY based reference points. Thus the qualitative score for #’s 4 and 5. 3. Catches for 2017 from IATTC Fishery Status report for tuna, 2016 (IATTC 2017).

IATTC
Ecuador

Last updated on 9 September 2019

Catch data is for the purse seine fishery only.

Download Source Data

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Fishery Improvement Projects (FIPs)

No related FIPs

Certifications

Marine Stewardship Council (MSC)

No related MSC certifications

Sources

Credits

SFP is grateful to the Global Sustainable Supply Chains for Marine Commodities (GMC) project for contributing to the development and update of this profile at several node levels. GMC is an interregional initiative implemented by Ministries and Bureaus of Fisheries and Planning of Costa Rica, Ecuador, Indonesia, and the Philippines, with technical support of the United Nations Development Programme (UNDP), facilitated by Sustainable Fisheries Partnership (SFP) and funded by the Global Environment Facility (GEF).

IATTC. 2015. Recommendations by the staff for conservation measures in the eastern Pacific Ocean, 2015. Document SAC-06-11.

IATTC. 2017. Conservation of tuna in the Eastern Pacific Ocean during 2017. Resolution C-17-01. http://www.iattc.org/PDFFiles2/Resolutions/C-17-01-Tuna-conservation-2017.pdf

Lehodey, P., Senina, I., Calmettes, B., Hampton, J., Nicol, S., Williams, P., Jurado Molina, J., Ogura, M., Kiyofuji, H., and Okamoto, S. 2011. SEAPODYM working progress and applications to Pacific skipjack tuna population and fisheries. WCPFC-SC7-2011/EB-WP 06 rev. 1.

Maunder, M.N. 2016. Status of skipjack tuna in the eastern Pacific Ocean in 2016. IATTC Document SAC-07-05c.

References

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    Skipjack tuna - Eastern Pacific Ocean, IATTC, Ecuador, Longlines

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