Parasite mitigation strategies in bay scallop aquaculture

View the project final report

Commodities

• Animals: shellfish

Practices

• Animal Production: parasite control
• Crop Production: Shellfish (Bay scallops)
• Education and Training: display, farmer to farmer, on-farm/ranch research, Conferences
• Farm Business Management: risk management
• Pest Management: prevention
• Production Systems: Aquaculture
• Sustainable Communities: employment opportunities, local and regional food systems, new business opportunities, sustainability measures

Since the 1980’s, the New England commercial bay scallop fishery has been in rapid decline. In New England, production of oysters and clams is primarily aquaculture based, and has brought jobs and local revenue to coastal areas. Bay scallops however, have yet to be efficiently commercially produced on a large scale. Studies and techniques are now available to optimize growth and survival in the nursery and grow-out of year one in bay scallop aquaculture settings. However, for highest market value, scallops need to grow for two years. Studies focused on cultivation practices within this second year are therefore needed to ensure the viability of bay scallop aquaculture. A major roadblock to producing shucked meats in bay scallop aquaculture is the prevalence of macroparasites. Macroparasites, such as pea crabs, mud blister worms, and boring sponge can have negative side effects on shellfish. Our study investigates culturing methods that can mitigate macroparasite prevalence and alleviate their negative effects on bay scallop growth. Previous studies indicate surface gear, such as lantern nets, are successful in mitigating macroparasite prevalence in year one. We hypothesize that continued use of lantern nets in year two could yield similar success in addition to the use biodegradable Netminder antifouling paint, which will mitigate macroparasite prevalence by preventing macroparasites from settle during their larval stages in the summer months.

1. Determine if Netminder antifouling paint reduces macroparasite prevalence during the overwintering phase. (Overwintering Experiment)

During the overwintering period, bottom cages, both Netminder coated and non-coated, will be stocked at a known density with naïve bay scallops. Macroparasite type and prevalence, the effect on invaded bay scallop health (shell height and meat weight), and the timing of the macroparasite invasion will be quantified across treatments.

2. Indentify if lantern nets and/or bottom cages are more successful in reducing macroparasite prevalence in bay scallops during the year two grow-out phase, and if the use of Netminder further reduces prevalence. (Year two grow-out Experiment)

During the year two grow out phase, hanging lantern nets and bottom cages, either Netminder coated or non-coated, will be stocked at a known density with naïve bay scallops. Shell height, meat weight, survival, and macroparasite prevalence will be assessed to quantify product health and market viability.