Shellfish Baseline Study

Coastal embayments along southern New England were once home to expansive eelgrass (Zostera marina) meadows as well as a diverse and abundant assemblage of fish and shellfish populations. These healthy ecosystems fueled vibrant coastal communities. Today, due to a range of human-induced environmental impacts including nutrient loading and overharvesting, many of these areas are now characterized by a loss of seagrass and severe declines in fish and shellfish populations. The waters around Nantucket, Massachusetts have seen declines in bay scallops (Argopecten irradians), hard clams (Mercenaria mercenaria), eastern oysters (Crassostrea virginica), channeled whelk (Busycotypus canaliculatus), and eelgrass over the years. However, in response there have been concerted efforts directed at mitigating humaninduced environmental issues driving these decreases as well as intensive shellfish restoration work aimed at facilitating the recovery of bay scallop, hard clam, and eastern oyster populations. Long-term benthic ecological monitoring programs are critical to understanding how human impacts are altering coastal ecosystems and evaluating the efficacy of shellfish population restoration work and initiatives aimed at mitigating environmental issues. A benthic ecological survey had been conducted every September for nearly a decade (2006 - 2014) in Nantucket Harbor up until a few years ago by the Maria Mitchell Association (most recently led by Dr. Peter Boyce).

We conducted a similar benthic ecological survey during September of 2019 and re-established an annual benthic ecological monitoring program, including the evaluation of seagrass coverage and the abundance of bay scallops, channeled whelk, and knobbed whelk. This data gave us valuable insight into the relative distribution and abundance of these species and provided a snapshot of the ecosystem health of Nantucket Harbor during September of 2019. Arguably more importantly, we are able to compare this data to data from benthic ecological surveys conducted from 2006 through 2014 to evaluate how these ecosystem parameters have changed over time and the effects of bay scallop restoration efforts and environmental impact mitigation measures.