Data from: Fossil dermal denticles reveal the pre-exploitation baseline of a Caribbean coral reef shark community
DOI10.5281/zenodo.5076165Zenodo5076165MaRDI QIDQ6725776
Dataset published at Zenodo repository.
Author name not available (Why is that?)
Publication date: 6 July 2021
Pre-exploitation shark baselines and the history of human impact on coral reef-associated shark communities in the Caribbean are poorly understood. We recovered shark dermal denticles from mid-Holocene (~7 ka) and modern reef sediments in Bocas del Toro, Caribbean Panama to reconstruct an empirical shark baseline before major human impact and quantify how much the modern shark community in the region had shifted from this historical reference point. We found that denticle accumulation rates, a proxy for shark abundance, declined by 71% since the mid-Holocene. All denticle morphotypes, which reflect shark community composition, experienced significant losses, but those morphotypes found on fast swimming, pelagic sharks (e.g., families Carcharhinidae and Sphyrnidae) declined the most. Analysis of historical records suggested that the steepest decline in shark abundance occurred in the late 20th century, coinciding with the advent of a targeted shark fishery in Panama. Although the disproportionate loss of denticles characterizing pelagic sharks was consistent with overfishing, the large reduction in denticles characterizing demersal species with low commercial value (i.e., the nurse shark Ginglymostoma cirratum) indicated that other stressors could have exacerbated these declines. We demonstrate that the denticle record can reveal changes in shark communities over long ecological timescales, helping to contextualize contemporary abundances and inform shark management and ecology.
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