What Causes Gray Meat in the Atlantic Sea Scallop in Georges Bank Closed Areas?

Atlantic sea scallop meats are normally firm and creamy white.  Large numbers of scallops with small, darkened (gray) and stringy adductor muscle (meat) were observed in the rotational management areas on Georges Bank. Scallop meat of different size classes were collected from re-opened areas and analyzed for meat quality and reproductive condition.  No direct correlation with size or senescence was found in gray meat scallops (p<0.05).  A progressive myodegeneration in the adductor muscle was observed (p<0.05).  The greater the percentage of myodegeneration, the more “discolored” and lower the meat quality.  Proximate analysis revealed higher moisture:protein ratios (7.4-15.0; p<0.05) in gray meat. A similar apicomplexan parasite found in a recent Iceland scallop mass mortality event was identified in gray adductor muscle. This parasite targets muscle tissue and may become pathogenic in hosts with concomitant infections or biotic stressors.  Intensive polychaete shell infestation was also associated with gray meat scallops and is being investigated as a contributing factor to the syndrome.  The parasite is transferred to other hosts via pseudo-feces and decomposition of infected muscle. Thus, high grading at sea and closing areas to fishing for extended periods may assist in propagating the infection in susceptible stocks.