Population dynamics of eastern oysters in the Choptank River Complex, Maryland during 1989–2015

Abstract

The eastern oyster (Crassostrea virginica) fishery in the Choptank River Complex (CRC), Maryland supports a large fishery. The CRC is also host to some of the largest oyster restoration projects in the world. Yet the relative effects of harvest and restoration on the population dynamics of eastern oyster in the CRC have not been assessed. We developed stage-based population models for each region of the CRC in AD Model Builder using dredge survey and harvest data provided by Maryland Department of Natural Resources from 1989 to 2015. Patterns in exploitation rates over time varied among regions. Abundance generally decreased during 1989–2003 and increased thereafter. Recruitment was greatest in the late 1990s, 2010, and 2012, which led to increases in abundance. Natural mortality was low across all regions during 2004-2015. Habitat, recruitment, and abundance declined 50–70% during 1989–2015, but fishery effort increased in years with higher abundance.