Recreational Overfishing of Reef Sharks: Human Incline vs Shark Decline

by Hailey Vaughan

Submitted : Spring 2020

Sharks have been on the brink of endangered and threatened status more than ever in the past few decades. The focus of this analysis is to look specifically at reef sharks since most research is typically done on pelagic shark species. This means nurse sharks will be excluded from the analysis because they are easily identifiable and more common, thus including them would skew results. Reef sharks are victims to the same anthropogenic abuses as pelagic sharks, such as habitat loss, degradation, pollution, finning and fishing.

            Professional research divers provided data per cells in the water column in reef habitats on shark population variation, or the frequency of sharks sighted. Using Hoenig’s formula for natural mortality across a wide species range, a variant of the Euler-Lotka equation specified to survival at age maturity, and density-dependent and density-independent models of population growth a few common trends were found. Shark sightings were low around areas with high human populations, except in areas like Florida, the Central Bahamas and the U.S Virgin Islands where strict fishing regulations are enforced. These results show that fishing, even in small amounts, is the biggest cause of shark mortality. Overfishing can bring reef shark populations down to 1% of their original population numbers within a few decades. This, however, shows that reef sharks still have a fighting chance if more fishing regulations are imposed or existing regulations are more strictly enforced.

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