Investigating the Impact of Multiple Factors on Gray Meats in Atlantic Sea Scallops (Placopecten magellanicus)

Abstract

The Atlantic sea scallop fishery is the one of the most valuable fisheries in North America. There is concern about scallops with low-quality adductor muscles, referred to as gray meats, impacting the fishery and the overall health of the stock because an apicomplexan parasite has been linked to gray meats and a mass mortality event that led to the collapse of the Icelandic scallop fishery. Yet, changes in scallop meat color have also been linked to the depletion of energy reserves in the adductor muscle following spawning. Seasonal scallop dredge surveys were conducted across Georges Bank, collecting data on scallop meat quality, scallop abundance, mortality, and reproductive cycles, as well as environmental parameters, including bottom depth and temperature. To investigate multiple causes for gray meats, a set of models were developed to examine the impact of biotic and abiotic factors on gray meat prevalence and meat quality of individual scallops. Model results indicate that different factors influence gray meat prevalence on the southern and northern parts of Georges Bank. In the south, location was a significant factor for predicting the presence of gray meats, highlighting Closed Area I where an outbreak of gray meats occurred after the area reopened to fishing. Yet in the north, reproductive stage was a significant factor, with scallops more likely to have discolored meats after spawning. Study results suggest that gray meats may be a symptom of poor condition that was caused by multiple factors and isolating a single cause may not be possible. Improved screening tests and continued monitoring of scallop health through targeted disease surveys is recommended.