Recopilación histórica de las captura de laúd (Dermochelys coriacea) en Perú y su relación con la medusa Scyphozoa Chrysaora plocamia

The Eastern Pacific population of leatherback turtles Dermochelys coriacea is Critically Endangered, with incidental capture in coastal and pelagic fisheries as one of the major causes. Given the population’s broad geographic range, status, and extensive overlap with fisheries throughout the region, identifying areas of high importance is essential for effective conservation and management. In this study, we created a machine-learning species distribution model trained with remotely sensed environmental data and fishery-dependent leatherback presence (n = 1088) and absence data (>500000 fishing sets with no turtle observations) from industrial and small-scale fisheries that operated in the eastern Pacific Ocean between 1995 and 2020. The data were obtained through a participatory collaboration between the Inter-American Convention for the Protection and Conservation of Sea Turtles and the Inter-American Tropical Tuna Commission as well as non-governmental organizations to support the quantification of leatherback vulnerability to fisheries bycatch. A daily process was applied to predict the probability of leatherback occurrence as a function of dynamic and static environmental covariates. Coastal areas throughout the region were highlighted as important habitats, particularly highly productive feeding areas over the continental shelf of Ecuador, Peru, and offshore from Chile, and breeding areas off Mexico and Central America. Our model served as the basis to quantify leatherback vulnerability to fisheries bycatch and the potential efficacy of conservation and management measures (Griffiths & Wallace et al. 2024; Endang Species Res 53:295-326). In addition, this approach can provide a modeling framework for other data-limited vulnerable populations and species.

Vulnerability of the Critically Endangered leatherback turtle to fisheries bycatch in the eastern Pacific Ocean. I. A machine-learning species distribution model

Lopez,

Griffiths,

Wallace

et al. 2024

Vulnerability of the Critically Endangered leatherback turtle to fisheries bycatch in the eastern Pacific Ocean. II. Assessment of mitigation measures

Griffiths,

Wallace,

Cáceres

et al. 2024

Industrial tuna and artisanal fisheries targeting multiple species in the eastern Pacific Ocean (EPO) interact with the Critically Endangered East Pacific (EP) leatherback turtle Dermochelys coriacea. In 2021, a revised Inter-American Tropical Tuna Commission (IATTC) resolution on sea turtles aimed to reduce sea turtle bycatch in EPO industrial tuna fisheries and ensure their safe handling and release. A new ecological risk assessment approach—Ecological Assessment for the Sustainable Impacts of Fisheries (EASI-Fish)—was used to assess vulnerability status and to better understand the potential efficacy of 70 scenarios that compared simulated conservation and management measures (CMMs) for EPO industrial (purse-seine and longline) and artisanal (longline and gillnet) fisheries to the status quo in 2019. In 2019, a fishing mortality proxy (F̃2019) and the breeding stock biomass per recruit (BSR2019) exceeded precautionary biological reference points (F80% and BSR80%), classifying the stock as ‘most vulnerable’. Industrial and artisanal longline fisheries had the highest impacts because they had the highest areal overlap with the modelled EP leatherback distribution. Of the 70 CMM scenarios, 42 resulted in significant improvements in vulnerability status (i.e. to ‘least vulnerable’). The use of large circle hooks, finfish bait, and best handling and release practices each decreased vulnerability; however, the most effective scenarios involved using these 3 measures in concert. The benefits predicted from EASI-Fish for CMM scenarios assume full compliance and attaining the modelled levels of efficacy, our modelling provides stakeholders with evidence-based recommendations to address key threats to EP leatherback turtles to improve their conservation status by reducing fishing impacts.

Post-release movements of leatherback turtles captured by the Peruvian small-scale driftnet fishery: insights from satellite telemetry

Mangel,

Pingo,

Jimenez

et al. 2024

The subpopulation of leatherback turtles Dermochelys coriacea in the eastern Pacific Ocean is classified as Critically Endangered due to multiple anthropogenic threats, the most urgent of which remains mortality at sea from fisheries interactions. Here we used satellite telemetry to assess the post-capture movements of leatherbacks in foraging grounds off Peru and attempt to evaluate post-release mortality. The 16 turtles tracked were bycatch from small-scale driftnet fishing vessels from the Peruvian ports of San Jose, Salaverry, and Parachique between 2014 and 2018. Sampled individuals included juveniles, subadults, and adults (curved carapace length range: 100.0 to 150.0 cm). Post-release overlap with driftnet fishing grounds was low and, upon release, all but one leatherback tracked for >30 d (n = 10) moved offshore beyond the continental shelf. From the subset of 6 tags with dive data, turtles spent 39.1 ± 11.8% of their time (range: 27.5 to 55.9%) within 10 m of the surface. Turtles spent significantly more time conducting shallow dives compared to deep dives during the day and night, carried out significantly more shallow dives compared to deep dives during the day and night, and carried out significantly more shallow dives during the day compared to night. Of the 16 tracks, biofouling (n = 3) and turtle injury or death (n = 3) were identified as the possible cause of tag cessation. Study results can inform ongoing population modeling and bycatch mitigation initiatives and efforts to predict and prevent bycatch interactions and mortality of this population.