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.

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.

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).