Unseen Experts of the Sea Fishers' Local Ecological Knowledge Reveals Elasmobranch Hotspot Decline Around Curaçao, Dutch Caribbean

Fishing pressure is the primary threat to coastal elasmobranch populations, and understanding its impact requires long-term regional data—often lacking in complex, small-scale fishery settings. This is the case for Curaçao, a southern Dutch Caribbean island with an unmonitored artisanal fishery where, according to anecdotes, elasmobranchs have severely declined but continue to be landed. In such data-limited regions, fishers' local ecological knowledge (FLEK) is a valuable tool for reconstructing historical baselines. Using FLEK from 21 surveys, we quantified historical and current elasmobranch diversity around Curaçao. Participatory mapping identified spatial distributional changes of 14 elasmobranch species, comparing the time of the surveys with fishers' career beginnings. Temporal trends were analysed alongside shifts in fishing efforts, socioeconomic contexts and perceptions of fishery management. Between 1957 and 2009, we identified 36 spatial hotspots of elasmobranch richness, which declined to 14 hotspots from 2010 to 2022, with a 4.3-fold greater likelihood of hotspots occurring in the past. Species richness in these areas significantly decreased from 7.44 ± 1.00 (mean ± s.e.) to 3.00 ± 1.18 species, while the number of fishers increased from 2.86 ± 0.23 fishers to 5.14 ± 0.49 per hotspot. Although not targeted, incidental elasmobranch catches are commonly retained. Most fishers expressed a desire for increased inclusion in fishery management but viewed elasmobranch-specific measures as unnecessary, perceiving local populations as healthy. We thus provide critical spatial baseline data for evidence-based conservation of elasmobranchs around Curaçao while emphasising the benefits and importance of engaging small-scale fishers in managing elasmobranch populations.