Fossil dermal denticles reveal the preexploitation baseline of a Caribbean coral reef shark community
Erin Dillon, Douglas J. McCauley, Jorge Manuel Morales‐Saldaña, Nicole D. Leonard, Jian‐xin Zhao, Aaron O’Dea
Abstract
Significance How abundant were sharks on Caribbean coral reefs before human impact? To explore this question, we recovered fossilized shark dermal denticles (scales) from a ∼7,000-y-old reef in western Caribbean Panama and compared them with denticles found on modern reefs in the same area. Our data suggest that sharks were over three times more numerous before humans began using marine resources in the area and that shark communities were compositionally different in the past, containing a higher proportion of fast-swimming, pelagic sharks. This reconstruction of preexploitation shark communities using fossil denticle assemblages demonstrates their potential to help contextualize recent declines in shark abundance, examine the ecological consequences of those declines, and guide shark management.