ESR 41:183-196 (2020) - DOI: https://doi.org/10.3354/esr01025
Multiple-threats analysis for loggerhead sea turtles in the southwest Atlantic Ocean
Milagros López-Mendilaharsu1,*, Bruno Giffoni1, Danielle Monteiro2,3, Laura Prosdocimi4, Gabriela M. Vélez-Rubio5,6, Alejandro Fallabrino5, Andrés Estrades5, Alexsandro Santana dos Santos1, Paulo H. Lara1, Thais Pires1, Manjula Tiwari7, Alan B. Bolten8, Maria Ângela Marcovaldi1
ABSTRACT: Priority-setting approaches for widely distributed and long-lived species can be challenging. This is especially true for sea turtles, which are species of conservation concern. The aim of this study was to conduct a detailed analysis of threats to identify, quantify and prioritize the main impacts to the loggerhead Caretta caretta population in the southwest Atlantic (SWA) region. A matrix of relative threats was constructed. Threats were identified and classified for 8 different life stages (nesting females, eggs, hatchlings, swim-frenzy transitional stage, juveniles-neritic, juveniles-oceanic, adults-neritic, adults-oceanic) and for 3 ecosystems inhabited by sea turtles (terrestrial, neritic and oceanic). Results indicated that fisheries bycatch represents a major threat for loggerheads in the SWA. The trawl fishery was identified as the main source of mortality for neritic juvenile and adult turtles, whereas juveniles in oceanic areas are mostly impacted by surface longlines. In terrestrial environments, eggs and hatchlings are mainly affected by habitat alteration and by native and exotic predators. Loggerheads have shown a positive nesting trend at their main nesting beaches in the SWA, probably due to long-term conservation efforts to reduce mortality of the different life stages within the terrestrial zone. However, the high mortality rates of juveniles and sub-adults documented at some known foraging grounds represent a reason for concern, as this may affect the overall population trend in the future. This threat analysis provides a tool to review the goals of national action plans, prioritize actions and optimize the allocation of management resources.
KEY WORDS: Caretta caretta · Sea turtle life stages · Conservation · Bycatch · Longline fishery · Trawl fishery · Management actions · Prioritization
Full text in pdf format  Supplementary material | Cite this article as: López-Mendilaharsu M, Giffoni B, Monteiro D, Prosdocimi L and others (2020) Multiple-threats analysis for loggerhead sea turtles in the southwest Atlantic Ocean. Endang Species Res 41:183-196. https://doi.org/10.3354/esr01025
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