Yellowfin tuna

In Ecuador, the Instituto Nacional de Pesca (INP) is the 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 Inter-American Tropical Tuna Commission (IATTC or CIAT in Spanish: Comisión Interamericana del Atún Tropical) is the entity which assesses, regulates and manages the tuna fishery in the Eastern Pacific Ocean. Ecuador is part of this Regional Fisheries Management Organization and responds to the resolutions adopted by this body. Ecuador does not manage this fishery but does participate in the management process by providing statistical information of relevance to the IATTC.

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

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 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’s interaction with other species and catch per unit of effort in longlines is not being collected. This generates a void in data and negatively impacts potential management options. Another measure taken in Ecuador by some tuna companies is the implementation of the Fisheries Improvement Project (FIP) aimed at getting the sustainability standard of the Marine Stewardship Council (MSC). As a 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), led by the Viceministerio de Acuacultura y Pesca through a participatory process that involves key players in the value chain of this fishery.

Port sampling for yellowfin tuna and other tuna is undertaken on a regular basis in Mexican ports to estimate size and species composition for use in stock assessments (IATTC 2011b).

All pole& line vessels need to be licensed and authorisations last 20 years. Licenses need renewal each year and renewal is subjected to submission of catch declaration from the previous year. Skippers are required to maintain logbook onboard (details include includes trip length, fishing days, fishing zone, species, the license details of the catching vessel, the weight landed and the average value) and all landings must be reported within 3 days to CONAPESCA (Arreguin-Sanchez et al 2011).

The Aquatic Resources Authority of Panama (ARAP) is in charge of fisheries management within the Republic of Panama. In December of 2010, Executive Order No. 486 was issued, which prohibited the use of longline vessels over 6 GRT. In December of 2011, Administrative Order No. 125 placed limits on the amount of fishing effort. Resolution No. ADM / ARAP 59, which occurred on May 10, 2011, creates a Multi-year Program for the Conservation of Tuna in the Eastern Pacific Ocean for the years 2011, 2012 and 2013 (ARAP 2011). Panama is also a member of the Inter-American Tropical Tuna Commission, and abides by those management measures as well.

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 (IUU) fishing (PAN-INDNR, in Spanish) came into effect. 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).

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. 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. 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. in port, inspectors monitor the landing and assess the reliability of the data in the logbook. A monitoring certificate is generated and delivered during the landing (Martínez-Ortiz et al. 2015). This data 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 fibra boats operating from the mother-ship) (Martínez-Ortiz et al. 2015).

Panama has been compliant with the majority of conservation and management measures set forth by the Inter-American Tropical Tuna Commission (IATTC) (IATTC 2014).There is no TAC in place for yellowfin tuna caught in the eastern Pacific Ocean.

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 occurs when they take the bait on the hooks, and become accidentally 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, hawksbill (Eretmochelys imbricata) and Kemp's ridley (Lepidochelys kempii) turtles are also captured (Gilman et al. 2006). According to the observers 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 (IATTC 2018)(IATTC 2018) 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. In 2017 Ecuador reported to the IATTC incidental catch of pelagic thresher (Alopias pelagicus), bigeye thresher (Alopias superciliosus), silky shark (Carcharhinus falciformis), oceanic whitetip shark (Carcharhinus longimanus), shortfin mako (Isurus oxyrinchus), blue shark (Prionace glauca) and giant manta ray (Manta birostris). Additional information regarding shark interactions with the Ecuadorian longline fleet targeting tuna is scarce but there are two studies. The first one conducted by the Instituto Nacional de Pesca (INP) (Pacheco 2010) on a Spanish longline fleet associated with Ecuador targeting tuna and other species. This study registered the capture of shortfin mako (Isurus oxyrinchus), smooth hammerhead (Sphyrna zygaena), blue shark (Prionace glauca), bigeye thresher (Alopias superciliosus) and leatherback turtle (Dermochelys coriacea). The second one, conducted by Martínez-Ortiz et al. (2015), states that shark catches 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 (2018) states that sharks are captured as incidental catch in the longline fishery within the Eastern Pacific Ocean. Ecuadorian national framework does establish 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 requiring specialized fishing gear adaptations.

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

Procuraduría Federal de Protección al Ambiente (PROFEPA) supervises protection of protected and endangered species in Mexican waters.

35 marine mammals have been reported off the west coast of Mexico, which include Short-beaked common dolphin (Delphiniums Delphi’s), Pacific white-sided dolphin (Lagenorhynchus obliquidens), humpback whales (Megaptera novaeangliae) and 5 species of turtles have been reported in the fishing area: hawksbill (Eretmochelys imbricata), loggerhead (Caretta caretta), leatherback (Dermochelys coriacea), Green or Black Turtle (Chelonia mydas agassizii), and Olive Ridley (Lepidochelys olivacea) (Arreguin-Sanchez et al 2011; Arellano Peralta 2010; Rosales-Nanduca et al 2011). A turtle conservation program has been in implementation in Mexico since 1972, with a national programme for protection and conservation of turtles created in 1994. Sea birds are under special protection under NOM-059-SEMARNAT-2001(Torres et al 1995; DOF 2004, 2006; Arreguin-Sanchez et al 2011).

Information on bycatch interactions in the Panama longline fishery are lacking. The Panama tuna longline fishery typically uses circle hooks, which likely reduce sea turtle interactions. For example, a study that occurred between Nov-Dec 2010, indicated that one turtle was caught for every 845 hooks(Vega et al., 2010).Information on seabird bycatch is limited and is not always reported {IATTC 2014}(http://cedepesca.net/promes/tuna-and-large-pelagics/panama-pacific-mahi-mahi-and-yellowfin-tuna/).

It does not appear that Panama has domestic management measures in place to deal with these bycatch species. However, Panama is a member of the Inter-American Tropical Tuna Commission, which does have some measures in place.

With respect to the Scombridae family, longline catches by the artisanal fleet are dominated by the bigeye tuna (Thunnus obesus) and also swordfish (Xiphias gladus), they represent an important amount of the catches (Martínez-Ortiz et al. 2015). Andraka et al. (2013) points to important bycatch species for this fishery being: bigeye, mahi mahi (Coryphaena hippurus), skipjack tuna (Katsuwonus pelamis), swordfish, sailfish (Istiophorus platypterus) and black marlin (Istiompax indica). Regarding the sailfish and swordfish, the structure of their population is well-known in the Pacific Ocean and genetic data analyses have been conducted to unveil whether there are differences among its geographical distribution (IATTC 2018). Despite this, it not has been possible to determine the current condition of the population of sailfish in the eastern Pacific Ocean with respect to specific management parameters such as the MSY (IATTC 2018). It is suggested that there exists capture that are not reported so is not possible to conduct a reliable assessment of this resource without additional catch estimations. On the other hand, IATTC assessments in the northern and south-eastern areas of the eastern Pacific Ocean suggest that the swordfish is not undergoing overfishing (IATTC 2018). Finally, in the case of the black marlin, no stock assessments have been conducted (IATTC 2018). The current stock status and impact of the fishery in species like mahi mahi (Coryphaena hippurus) 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 these species (mahi mahi), is the current assessment of its fishery in Ecuador against the Marine Stewardship council standard, which could help to some extent, to quantify properly the accumulated impact on this species

Estimated target reference points or regulations in Ecuador focused on controlling the capture and landings of the other bycatch species have not been defined and a relative population analysis should be conducted with more accurate and reliable capture and effort data.

There is reported bycatch (less than 5% of the retained catch) of juvenile yellowfin tuna and skipjack tuna which are not retained due to low market price. Other species reportedly caught in this fishery include mahi mahi (Coryphaena hippurus_), black skipjack tuna, wahoo (Acanthocyium solandri_), Sharks, mackerels, Pacific bluefin tuna (Thunnus orientalis) and bigeye tuna. Al shark species caught in this fishery are reportedly released alive or discarded due to low market demand (Arreguin-Sanchez et al 2011).

Handlines and Pole and line fishery has no associated by catch of dolphins and other marine mammals and their impact on non-target species is nominal to low. Discards have never been foramlly reported or quantified in Mexican pole & line fishery (Arreguin-Sanchez et al 2011).

Fleets targeting yellowfin tuna stock in the purse seine fisheries may affect dolphin schools due to their association with yellowfin tuna schools in the Eastern Pacific Ocean (Joseph 1994; Hall, 1998; Vaca-Rodriguez and Enriquez-Andrade 2006; Roman-Verdeoto and Orozco-Zoller 2005).

In Panaam, the most common by-catch in longline fishery off the Gulf of Chiriquí, 3 species of sharks (_Alopias pelagicus, Carcharhinus porosus, Spyrna lewini). Other species caught in the longline included Sphyraena ensis, Sarda orientalis, Tylosurus pacificus, and Thunnus occidentalis). By-catch of sharks in the longline fishery off Panama is relatively low due to the use of circle hooks, with studies showing that between Nov-Dec 2010, one shark was caught for every 1230 hooks (Vega et al., 2010). Panama has banned shark finning, in accordance with IATTC requirements {IATTC 2014}. Panama is lacking data collection protocols for bycatch (http://cedepesca.net/promes/tuna-and-large-pelagics/panama-pacific-mahi-mahi-and-yellowfin-tuna/).

Last updated on 04 Dec 2013

Under Resolution C-11-01 of IATTC for Conservation of Tuna in the Eastern Pacific Ocean Purse seiners over 182 metric tons carrying capacity ((IATTC size classes 4, 5 and 6) fishing for tunas in the Eastern Pacific Ocean shall cease fishing for 62 days from either (1) 29 July to 28 September; or (2) 18 November to 18 January 2012 during the current year (IATTC 2011).

The coastal limits of yellowfin distribution in the Pacific Ocean were documented by Rosa (1950, in Bayliff 1980) who reported that this species range is from Point Conception, California, to San Antonio or Talcahuano, Chile, along the eastern Pacific coastline. Blackburn (1965, in Bayliff 1980) suggested that the longitudinal limits of yellowfin are about 35°N in the eastern north Pacific and 33°S in the eastern South Pacific, 40°N in the western north Pacific and 35°S in the western South Pacific. Temperature is an important determinant of the horizontal distribution of yellowfin. The studies on larvae distribution indicate that they are trans-Pacific in occurrence, although their distribution is limited latitudinally to tropical and subtropical waters. Larvae occur year-round in equatorial waters, but there is a seasonal change in density in the subtropical waters of the western Pacific. Further, Klawe (1963, in Bayliff 1980) examined the vertical distribution of yellowfin larvae in the eastern Pacific, finding no evidence of the occurrence of larvae below the thermocline. Suzuki et al. (1978, in Hall and Lennert 1992), stated that data on the distribution of yellowfin larvae also show concentrations in coastal zones, although larvae are present in most areas, and there is a concentrated area offshore. With this information, it is likely that yellowfin tuna returns to the coastal zone to spawn, taking advantage of the subsurface Cromwell Current. Regarding juvenile yellowfin in the eastern Pacific, they have been recorded from approximately 24°N off Baja California to approximately 2°S, just off the coast of Ecuador (Bayliff 1980).

Last updated on 02 Jul 2012

Currently, there are very limited restrictions in place for pole and line fisheries in the Mexican EEZ off EPO waters. All pole&line vessels need to be licensed; and restrictions include prohibition on fishing within 12 miles form Islas Revillagigedo group of islands in the Pacific Ocean, which is far beyond the opertional range of pole& line vessels (Arreguin-Sanchez et al 2011).

Under Resolution C-11-01 of IATTC for Conservation of Tuna in the Eastern Pacific Ocean Purse seiners over 182 metric tons carrying capacity ((IATTC size classes 4, 5 and 6) fishing for tunas in the Eastern Pacific Ocean shall cease fishing for 62 days from either (1) 29 July to 28 September; or (2) 18 November to 18 January 2012 during the current year (IATTC 2011).

IATTC Closures for purse seiners (IATTC 2011):
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.

Last updated on 04 Dec 2013

Under Resolution C-11-01 of IATTC for Conservation of Tuna in the Eastern Pacific Ocean Purse seiners over 182 metric tons carrying capacity ((IATTC size classes 4, 5 and 6) fishing for tunas in the Eastern Pacific Ocean shall cease fishing for 62 days from either (1) 29 July to 28 September; or (2) 18 November to 18 January 2012 during the current year (IATTC 2011).

Pelagic fishing gear has nominal adverse effects on coastal and marine habitats.

Last updated on 02 Jul 2012

The Pacífico Occidental de Panamá (POP) which includes the Gulf of Chiriqui covers an area of 1,380,293 ha and extends up to 200 m depth. The POP area has eight marine protected areas, with the largest of them being the Coiba National Park (Guzman et al., 2004; Vega et al., 2010).

Under Resolution C-11-01 of IATTC for Conservation of Tuna in the Eastern Pacific Ocean Purse seiners over 182 metric tons carrying capacity ((IATTC size classes 4, 5 and 6) fishing for tunas in the Eastern Pacific Ocean shall cease fishing for 62 days from either (1) 29 July to 28 September; or (2) 18 November to 18 January 2012 during the current year (IATTC 2011).

IATTC Closures for purse seiners (IATTC 2011):
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.

Recruitment to the fishery occurs at about 40 cm, at which size yellowfin tuna associated with floating objects in the Panama Bight and Central American coast. During this period they seem to be retained in the coastal zone by current systems that also keep the floating objects in that area (Hall and Lennert 1992). Young tuna are associated more frequently with dolphinfish which may represent an adaptive pattern which is likely to benefit the tuna in their search for food (Hall and Lennert 1992).

Blackburn (1969, in Bayliff 1980) stated that the availability of forage organisms in areas of optimum temperature is an important factor in determining where yellowfin tend to aggregate. Yellowfin gathers in areas of upwelling and ocean frontal boundaries between the Equatorial Countercurrents and the South Equatorial Current (Blackburn, 1965; Murphy & Shomura, 1972; Uda, 1973; Yamanaka, 1978, in Bayliff 1980). Many carnivorous fish and marine mammals can be found in the same areas as yellowfin, mostly feeding competitors, e.g. the bigeye tuna, skipjack tuna, the spotted dolphin (Stenella attenuata) and the spinner dolphin(Stenella longirostris); Waldron and King (1963, in Bayliff 1980) noted that squids were common in the diet of this species.

The IATTC (2018) presents the trophic structure of the eastern Pacific Ocean 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 with 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 done by the Ecuadorian scientific advisory body have been found, mostly this analysis falls on the IATTC.