Although raising finfish and shellfish in captivity can reduce fishing pressures on wild populations, the aquaculture industry can also be a source of aquatic invasive species (AIS) introductions. By raising finfish and shellfish at high densities, opportunities are created for exotic pathogen growth, algal blooms, and escapes of cultured fish. The Division of Marine Fisheries (MarineFisheries) has approved aquaculture regulations ( 322 CMR 13.00 ) that prohibit the release of non-indigenous marine organisms.
Key Management Practices for the Aquaculture Industry:
Prevention and education efforts for aquaculture include:
- Hazard Analysis and Critical Control Point (HACCP) Planning for Natural Resource Management - Information and trainings supported by the U.S. Fish and Wildlife Service and the University of Texas - Arlington.
The Massachusetts Aquatic Invasive Species Management Plan contains information on these specific seafood pathways:
- Shellfish seed import - Shellfish seed is commonly grown in hatcheries and imported to Massachusetts for use in shellfish culture operations. While Massachusetts AIS Working Group partners at MarineFisheries carefully regulate the sources of seed for this industry, there is the potential for the import of shellfish pathogens and other organisms associated with shellfish illegally introduced from out of state.
- Use of cultch - Several shellfish species cultured in Massachusetts seek clean, hard surfaces to settle, attach, and grow. Placing shellfish waste (shells and associated materials, or cultch) in grow-out areas attracts settling juveniles of desirable species, such as the eastern oyster (Crassostrea virginica). However, there is some concern over cultch sources, as well as disinfection techniques that need to be in place to minimize the potential transport of shellfish pathogens or other associated nonindigenous species.
- Finfish culture - Growth and maintenance of finfish in open systems—such as raceways, flow-through tanks, and net pens—expose surrounding aquatic systems to pathogens associated with cultured fish populations. The Division of Fisheries and Wildlife (DFW) carefully regulates this industry, requiring that species be isolated from the natural system when they are not native to the watershed. DFW maintains and periodically updates a list of species that can be cultured in Massachusetts under specified conditions.
- Genetic dilution - Cultured fin and shellfish are often imported or altered genetic stocks are selected for maximum growth or some other desirable trait (i.e., shell shape and color) in the selected culture setting. Cultured stocks are usually at a disadvantage in competing with wild populations. Therefore, interbreeding with wild populations may dilute the wild genetic pool, making offspring more poorly adapted to life in natural systems. While there are currently few marine finfish operations in Massachusetts, such operations are common in other parts of the Gulf of Maine and could make their way to the Massachusetts coast. Shellfish growing operations are abundant in the Commonwealth, particularly on Cape Cod.
View the full text of this section on page 22 of the Massachusetts Aquatic Invasive Species Management Plan.
If you have specific questions about aquaculture and AIS, please contact us.