DOI: 10.5061/dryad.69p8cz95d
title: Data from: Hidden demographic impacts of fishing and environmental drivers of fecundity in a sea turtle population

description: 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.
description: Here we present materials and scripts for all models presented or
 referred to in our publication: Hidden demographic impacts of fishing and
 environmental drivers of fecundity in a sea turtle population. 
 For stochastic models, we present all simulated
 datasets. Demographic data were collected from João
 Barrosa loggerhead nesting beach, Boa Vista (16.014°N, 22.735°W), approved
 by the National Directory of the Environment of Cabo Verde and received ethical approval following
 strict international animal care guidelines (permit numbers: DGA:
 21/2013-22/2015; DNA: 16/2016-51/2019).
 No third-party data has been
 reproduced here. Raw data on animal observations are not
 presented here, only data on turtle remigration intervals as a model
 script dependency. Raw bycatch data are not presented here, only
 summarized estimates of annual mortality of female loggerhead turtles from
 Boa Vista as a model script dependency.
 Publicly available net primary
 productivity data on the EU Copernicus Marine Environment Monitoring
 Service have been summarized in a file that is used as a model script
 dependency. Annotations and READMEs describe preliminary
 analysis, processing for each dataset, and output simulation
 data.
description: All models run correctly as intended with latest versions of R, R
 Studio, all packages updated and current at the time of publication (May
 2023).