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ABSTRACT. Prior to 2007, efforts to monitor and conserve hawksbill turtles (Eretmochelys imbricata) in the eastern Pacific Ocean were opportunistic and records were virtually non-existent. The first abundance estimates were published in 2010, but contained limited data on the species. Ongoing research since that time has led to the identification of several rookeries, including sites containing large proportions of the overall hawksbill nesting currently known to occur in the region. Monitoring projects were established at several sites and have since provided substantial nesting data on the species. Here we summarize data collected between 1983 and March 2016 from all sites (n = 9) confirmed to host >10 nests in any given season to provide an update on hawksbill nesting in the eastern Pacific. We documented a total of 3,508 hawksbill nests, 265,024 hatchlings and 528 individual nesting females in the region. The vast majority of these records (99.4%, 99.9% and 99.6%, respectively) were generated subsequent to 2007, coinciding with the discovery of eight of the nine rookeries included in this study and the organization of monitoring efforts at those sites, which led to the increased documentation conferred here. Our findings should not be misconstrued as increases in actual nesting or signs of recovery, which could diminish the ongoing need for conservation actions, but rather as optimism, that there is still an opportunity to restore the species in the eastern Pacific. The top three sites in terms of average annual number of nests were Estero Padre Ramos (Nicaragua; 213.2 ± 47.6 nests), Bahia de Jiquilisco (El Salvador; 168.5 ± 46.7 nests) and Aserradores (Nicaragua; 100.0 ± 24.0 nests), and all three sites are located in mangrove estuaries in Central America, highlighting the importance of these rookeries/habitats for the survival and recovery of hawksbills in the region. The remaining six sites received between 6.9 ± 7.3 nests (Costa Careyes, Mexico) and 59.3 ± 17.7 nests (Los Cobanos, El Salvador) annually. By integrating data collected on nesting hawksbills with local conservation realities at the most important known hawksbill rookeries in the eastern 572 2 Latin American Journal of Aquatic Research Pacific, we provide a more holistic view of the conservation status and management needs of the species in this ocean region.

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In Ecuador, one of the main hazards for threatened marine species, such as sea turtles, is small-scale fisheries bycatch. At a global scale, currently, bycatch reduction technologies (BRTs) are being tested in many coastal nations to mitigate this issue. Despite some advances in Ecuadorian efforts for wildlife protection, BRTs to reduce bycatch have yet to be assessed. The purpose of this study was to test the BRT of net illumination using violet light-emitting diodes (LEDs) as a mitigation measure to reduce sea turtle interactions in the small-scale driftnet fishery operating from the ports of Santa Rosa, Puerto Lopez and Jaramijo. A total of 146 pairs of experimental sets (control and illuminated panes) were deployed in all ports. A generalized linear mixed-effect model (GLMM) was employed to analyze the bycatch per unit of effort (BPUE) for sea turtles, and the catch per unit of effort (CPUE) for target species; for both control and illuminated panes. Thirty-two sea turtles from three species were observed captured: olive ridley Lepidochelys olivacea (n=18), green Chelonia mydas (n=13) and leatherback turtles Dermochelys coriacea (n=1). Turtle species-specific modeling showed bycatch of green turtles declined by 93% in illuminated nets compared with control, non-illuminated nets, whereas no significant difference between control and illuminated nets was observed for olive ridley turtles. The catch per unit effort of the target pelagic fish species including skipjack tuna, yellowfin tuna, mahi-mahi, thresher shark and smooth hammerhead shark was not affected by net illumination. Our results represent the first evaluation of the effects of net illumination using LEDs on reducing marine turtle bycatch in Ecuadorian small-scale driftnet fisheries. Despite its relatively small sample size, these results could be used by fisheries managers to support the implementation or further testing of this BRT in gillnet fisheries along the Ecuadorian coast.

www.nature.com/scientificreports enhanced, coordinated conservation efforts required to avoid extinction of critically endangered Eastern Pacific leatherback turtles the Laúd opo network † Failure to improve the conservation status of endangered species is often related to inadequate allocation of conservation resources to highest priority issues. Eastern Pacific (EP) leatherbacks are perhaps the most endangered sea turtle population in the world, and continue on a path to regional extinction. To provide coherent, regional conservation targets, we developed a population viability analysis and examined hypothetical scenarios describing effects of conservation activities that either reduced mortality or increased production of hatchlings (or both). Under status quo conditions, EP leatherbacks will be extirpated in <60 yr. To ensure a positive, long-term population trajectory, conservation efforts must increase adult survivorship (i.e., reduce adult mortality) by ≥20%, largely through reduction of fisheries bycatch mortality. Positive trajectories can be accelerated by increased production of hatchlings through enhanced nest protection and treatment. We estimate that these efforts must save approximately 200-260 adult and subadult leatherbacks and produce approximately 7,000-8,000 more hatchlings annually. Critically, reductions in late-stage mortality must begin within 5 years and reach 20% overall within the next 10-15 years to ensure population stabilization and eventual increase. These outcomes require expanded, sustained, coordinated, high-priority efforts among several entities working at multiple scales. Fortunately, such efforts are underway.Species declines driven by human causes have been well-documented across taxonomic groups in recent decades 1 . In some cases, persistent, effective conservation efforts -often coupled with enforced legal protections -have stabilized and even begun to recover populations 2 . Among long-lived marine species such as marine mammals, turtles, birds, and elasmobranchs, there is wide variation in long-term population trends and whether conservation efforts have successfully achieved recovery goals 3-5 . For populations to recover, threats must be reduced to levels that first stabilize, then increase population abundance; however, failure to recover depleted populations often is related to insufficient (i.e., too little for too short a time period) or inefficient allocation of limited resources to conservation actions of highest potential benefit to the target population 6 .Marine turtles exemplify these issues, given their global distributions and varied conservation status among regional population segments (i.e., regional management units, RMUs; Ref. 7 ). Many RMUs within and among the seven extant marine turtle species are depleted relative to historical abundance because of human-caused mortality, namely direct harvest of turtles and their eggs and incidental capture in fisheries 8 . However, some marine turtle populations are showing signs of recovery following conservati...