1
|
Roast MJ, Martins S, Fernández-Peralta L, Báez JC, Diame A, March D, Ouled-Cheikh J, Marco A, González-Solís J, Cardona L. Hidden demographic impacts of fishing and environmental drivers of fecundity in a sea turtle population. Conserv Biol 2023; 37:e14110. [PMID: 37144486 DOI: 10.1111/cobi.14110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 02/22/2023] [Accepted: 04/23/2023] [Indexed: 05/06/2023]
Abstract
Fisheries bycatch is a critical threat to sea turtle populations worldwide, particularly because turtles are vulnerable to multiple gear types. The Canary Current is an intensely fished region, yet there has been no demographic assessment integrating bycatch and population management information of the globally significant Cabo Verde loggerhead turtle (Caretta caretta) population. Using Boa Vista island (Eastern Cabo Verde) subpopulation data from capture-recapture and nest monitoring (2013-2019), we evaluated population viability and estimated regional bycatch rates (2016-2020) in longline, trawl, purse-seine, and artisanal fisheries. We further evaluated current nesting trends in the context of bycatch estimates, existing hatchery conservation measures, and environmental (net primary productivity) variability in turtle foraging grounds. We projected that current bycatch mortality rates would lead to the near extinction of the Boa Vista subpopulation. Bycatch reduction in longline fisheries and all fisheries combined would increase finite population growth rate by 1.76% and 1.95%, respectively. Hatchery conservation increased hatchling production and reduced extinction risk, but alone it could not achieve population growth. Short-term increases in nest counts (2013-2021), putatively driven by temporary increases in net primary productivity, may be masking ongoing long-term population declines. When fecundity was linked to net primary productivity, our hindcast models simultaneously predicted these opposing long-term and short-term trends. Consequently, our results showed conservation management must diversify from land-based management. The masking effect we found has broad-reaching implications for monitoring sea turtle populations worldwide, demonstrating the importance of directly estimating adult survival and that nest counts might inadequately reflect underlying population trends.
Collapse
Affiliation(s)
- Michael J Roast
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals (BEECA), Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Samir Martins
- BIOS.CV, Environmental Conservation and Sustainable Development, Sal Rei, Cabo Verde
| | | | - José Carlos Báez
- Centro Oceanográfico de Málaga, IEO (CSIC), Fuengirola, Spain
- Instituto Iberoamericano de Desarrollo Sostenible (IIDS), Universidad Autónoma de Chile, Temuco, Chile
| | - Ahmed Diame
- BirdLife Africa, West Africa Sub-Regional Office, Dakar, Senegal
| | - David March
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals (BEECA), Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca de la Biodiversitat (IRBio), Barcelona, Spain
- Centre for Ecology and Conservation, College of Life and Environmental Science, University of Exeter, Penryn, UK
| | - Jazel Ouled-Cheikh
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals (BEECA), Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca de la Biodiversitat (IRBio), Barcelona, Spain
| | - Adolfo Marco
- Estación Biológica de Doñana, CSIC, Sevilla, Spain
| | - Jacob González-Solís
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals (BEECA), Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca de la Biodiversitat (IRBio), Barcelona, Spain
| | - Luis Cardona
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals (BEECA), Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
- Institut de Recerca de la Biodiversitat (IRBio), Barcelona, Spain
| |
Collapse
|