Data and code for: Catch-and-release is on the rise, but large fish remain vulnerable

Catch-and-release (C&R) is widely promoted to reduce harvest mortality and support sustainable recreational fisheries. However, understanding its ecological, social, and management implications remains limited by the lack of large-scale, long-term datasets revealing whether C&R practices differ among species and change over time. We analysed over one million caught fish (2011–2024) across 39 species and 1 286 Swedish inland fisheries, reported via the online licence platform iFiske AB. The prevalence of C&R increased from ~53% to 71% during 2011-2024, though trajectories and magnitudes differed among species. Size-specific analyses showed that longer individuals were released less frequently than shorter conspecifics for four of the six main target species (northern pike, European perch, zander, European grayling, brown trout, and Arctic char). Our findings indicate that recreational fisheries are shifting towards lower exploitation rates, but also highlights a size-dependen..., Through a research collaboration with iFiske, we accessed a dataset of 593 842 anonymised catch report entries from 2011–2024, including both public and non-public entries. Each report contained information on the date of angling, species captured, fish sizes, and whether fish were released. To ensure consistency, we first excluded reports involving non-angling methods (e.g. passive gear), representing approximately 1.4% of the total. We then excluded zero-catch reports (37%). Finally, we removed reports lacking release information (<1%). This resulted in a final dataset of 354 562 report entries covering 1 080 197 individual catch records of 39 fish species across 1 286 fisheries.
We tested for temporal trends in catch-and-release (C&R) practices using generalised linear mixed models (GLMMs), fitted with the glmmTMB package. Further, we tested for an association between fish length and C&R practice with generalised additive mixed models (GAMMs), implemented in the mgcv pack..., # Data and code for: Catch-and-release is on the rise, but large fish remain vulnerable

Dataset DOI: [10.5061/dryad.3ffbg79z0](https://doi.org/10.5061/dryad.3ffbg79z0)

## Description of the data and file structure

Scripts and the data file were used to evaluate temporal trends in catch-and-release (C&R) practices as well as species- and size-specific release rates across inland fisheries, encompassing 1 286 independent lake and river systems in Sweden.

We used a unique and extensive database of individual records of captured fish and C&R history, dating back to 2010, provided by the online fishing license sales platform iFiske AB ([https://www.ifiske.se/](https://www.ifiske.se/)). iFiske is the largest provider of digital fishing licenses in Sweden and they actively send emails encouraging anglers to submit catch reports immediately after the license have expired.

Pre-processing:

We excluded reports that involved non-angling methods (e.g. passive gear), reports missing release inf..., ,