Fossil dermal denticles reveal the preexploitation baseline of a Caribbean coral reef shark community.

Autor:	Dillon EM; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106; erinmdillon@ucsb.edu.; Smithsonian Tropical Research Institute, Balboa, Republic of Panama., McCauley DJ; Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106.; Marine Science Institute, University of California, Santa Barbara, CA 93106., Morales-Saldaña JM; Smithsonian Tropical Research Institute, Balboa, Republic of Panama., Leonard ND; Radiogenic Isotope Facility, School of Earth and Environmental Sciences, The University of Queensland, QLD 4072 Brisbane, Australia., Zhao JX; Radiogenic Isotope Facility, School of Earth and Environmental Sciences, The University of Queensland, QLD 4072 Brisbane, Australia., O'Dea A; Smithsonian Tropical Research Institute, Balboa, Republic of Panama.; Department of Biological, Geological, and Environmental Sciences, University of Bologna, 40126 Bologna, Italy.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2021 Jul 20; Vol. 118 (29).
DOI:	10.1073/pnas.2017735118
Abstrakt:	Preexploitation shark baselines and the history of human impact on coral reef-associated shark communities in the Caribbean are tpoorly understood. We recovered shark dermal denticles from mid-Holocene (∼7 ky ago) and modern reef sediments in Bocas del Toro, Caribbean Panama, to reconstruct an empirical shark baseline before major human impact and to quantify how much the modern shark community in the region had shifted from this historical reference point.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. An 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. Competing Interests: The authors declare no competing interest.
Databáze:	MEDLINE
Externí odkaz:	Zobrazit plný text záznamu