Back
Case Study

Things to Be Aware of From a Shellfish Sanitation Perspective

This document was generated by DMR Bureau of Public Health staff and reflects things to be aware of when considering an aquaculture lease application from a shellfish sanitation perspective.

Author(s)

Maine Department of Marine Resources Bureau of Public Health

Source

Maine Department of Marine Resources Bureau of Public Health

Date
2020
casco-bay-8712.jpg

Things to be aware of when considering an aquaculture lease application from a shellfish sanitation perspective:

Water Quality

We recommend that you check with DMR’s Bureau of Public Health before selecting a site to ensure that it is not trending toward a classification downgrade that could take it from being an approved area to a closed area. Shellfish growing areas that are in a classification other than Approved require additional permits and processes for harvest including depuration (cleansing) of the product, relay or seasonal closures. Should an area be downgraded, meaning it changes from an open area to a lesser classification such as restricted or prohibited, an LPA located within the area may be renewed for only one additional year then it must be discontinued. The water quality data are available on the DMR website through an interactive web map, but you can also reach out to a staff member in the Bureau of Public Health to discuss your proposed site in detail. Downgrades and upgrades of shellfish growing areas are determined annually. https://www.maine.gov/dmr/shellfish-sanitation-management/programs/growingareas/index.html

Prohibited Areas

Only seed may be grown by aquaculturists in Prohibited areas. When selecting your nursery site, you must consider the location of any wastewater treatment plant facilities near the proposed location. Each of these facilities has an EPA defined toxic mixing zone where receiving water is at a 300:1 ratio to treated wastewater. This zone is unsafe for the culture of shellfish and no aquaculture activities are permitted. DMR has an online tool that allows you to view these zones and is a helpful resource in determining placement of any potential site. https://www.maine.gov/dmr/shellfish-sanitation-management/maps/index.html

Biotoxin

When selecting a site, you should also consider what the biotoxin closure trends are for the area and species that you are proposing. For instance, if you want to grow mussels, but the area you selected is historically closed for several months in the summer due to toxic phytoplankton blooms, you may want to reconsider your site or develop a business plan that can accommodate a long-term closure. Standard or experimental leaseholders may obtain a memorandum of understanding (MOU) with the Department to allow for site specific biotoxin testing during closure events which can authorize harvest if levels are acceptable. Limited Purpose Aquaculture permit holders cannot obtain MOUs. You can contact a staff member in the Bureau of Public Health to discuss historic biotoxin data from your area. Biotoxin closure information can be found here: https://www.maine.gov/dmr/shellfish-sanitation-management/closures/index.html

High Risk Species

Be aware of species considered high risk for biotoxin. High risk species are species that typically hold biotoxin longer than other species or become more toxic over time regardless of additional exposure. In order to harvest high risk species the grower must have an MOU and lot sampling at the growers expense is often required to ensure a safe product. Because MOUs are required for harvest, high risk species cannot be grown to commercial size on LPAs. Examples of high risk species include whole or roe on scallops, razor clams and surf clams. You can find a document regarding DMR policy on high risk species here: https://www.maine.gov/dmr/shellfish-sanitation-management/forms/biotoxin.html


Case studies are authored by industry members at the request of The Maine Aquaculturist. Authors are selected based on experience and expertise in a key business aspect of aquaculture. See our About page for more information.

Related Resources