Seasonality

Your best bet it to contact the Department of Marine Resources Division of Aquaculture staff and ask nicely. Due to circumstances outside of their control, the best they can do is give a ballpark estimate. It’s important to understand that the Division of Aquaculture staff would give you an exact time if they could.

Spring through early winter when there is food (phytoplankton) in the water and no ice. Temperature is the primary driver of food availability which can help you determine when oysters begin to feed again. Some farms are able harvest and sell year-round by using sites that remain accessible in winter and don’t ice over. This gives them a big advantage over farms that only sell in the warmer months — both in accessing markets and having year-round income.

The key is to sink your gear before ice forms, keep them out of mud that will suffocate and kill them, and raise them as soon as the conditions are right (not too early and not too late).

Sinking: Winter has a tendency to come as early as Thanksgiving in Maine, so plan ahead and don’t wait until the week before a deep freeze to sink all of your cages. Ice will kill your oysters and displace gear. Keep them out of the mud when you sink them. When sinking cages with floats on one side, the floats should be down (touching the bottom) so the cage is held out of any mud. Even the most skilled operators end up with several cages upside down or on their sides – you can’t avoid this. You will need to dive the bottom (or hire divers) to go through and right any misoriented cages. Some farms have developed systems to sink and raise their cages using a chute that cages slide up and down and a framed in winch and pulley system.

Growing and overwintering sites: Some farms grow in shallower, warmer, more exposed areas with fast growth rates during the growing season and then move their oysters to a more protected deeper location during the harsh winter months.

Raising: The key to raising and beginning to process your oysters is waiting until waters are warm enough (> 40 degrees Fahrenheit at which temperature they begin feeding) and food sources are available, but not so long that they suffocate. After a long winter dormant on the bottom, your oysters will be weak and starved. Raising and processing them causes stress and mortalities if they haven’t begun to feed yet. Instead, wait until the water warms a bit and check with local scientists to see if food sources are present yet, which happens in spring. Don’t wait too long either, because once the water warms the densely packed oysters will begin trying to feed again and will smother in high densities and muddy bottom conditions. Killing oysters from ill-timed raising is a very common and avoidable rookie mistake.

Bacterial closures, which are generally caused by high rainfall events, are most prevalent in spring and fall and can be highly site-specific. Biotoxin closures are based on the phytoplankton bloom season which is unpredictable and changes from year to year generally occurring between May and December. You should contact the DMR Bureau of Public Health to get a sense of the timing and frequency of biotoxin and bacterial closures. You should also check their maps before harvesting any shellfish. This can help you anticipate and plan ahead for times when you can’t harvest and sell your crops. See our Public Health page for more information.

For most shellfish, the summer months are when an array of biofouling and pests are most likely to occur, although barnacle set occurs in both winter and spring. Keep an eye out for any biofouling or pests during your sorting activities because addressing it early is the key to preventing loss of quality. Some growers use salt brines or simply dry out gear in the sun to remove them; however, some pests may need a more robust treatment.

Commercial mussel farms in Maine operate year-round.

Bacterial closures, which are generally caused by high rainfall events, are most prevalent in spring and fall and can be highly site-specific. Biotoxin closures are based on the phytoplankton bloom season which is unpredictable and changes from year to year generally occurring between May and December. You can contact the DMR Bureau of Public Health to get a sense of the timing and frequency of biotoxin and bacterial closures. You should also check their maps before harvesting any shellfish. This can help you anticipate and plan ahead for times when you can’t harvest and sell your crops. See our Public Health page for more information.

For most shellfish the summer months are when an array of biofouling and pests are most likely to occur; although barnacle set occurs in winter and spring. Keep an eye out for any biofouling or pests during your sorting activities because addressing it early is the key to preventing loss of quality. Some growers use salt brines or simply dry out gear in the sun to remove them however, some pests may need a more robust treatment.

Spring through early winter when there is food (phytoplankton) in the water and no ice.

If you are selling meats only, the Bureau of Public Health Closures will not restrict sale. However, if you plan to sell whole or roe-on scallops, biotoxin and bacterial closures do apply. Bacterial closures, which are generally caused by high rainfall events, are most prevalent in spring and fall and can be highly site-specific. Biotoxin closures are based on the phytoplankton bloom season which is unpredictable and changes from year to year generally occurring between May and December. You can contact the DMR Bureau of Public Health to get a sense of the timing and frequency of biotoxin and bacterial closures to help you anticipate and plan ahead for times when you can’t harvest and sell your scallops. See our Public Health page for more information.

For most shellfish the summer months are when an array of biofouling and pests are most likely to occur; although barnacle set occurs in winter and spring. Keep an eye out for any biofouling or pests during your sorting activities because addressing it early is the key to preventing loss of quality. Some growers use salt brines or simply dry out gear in the sun to remove them however, some pests may need a more robust treatment.

The kelp season is late fall through late spring.

Kelp biofouling is linked to increases in water temperature, so keep a close eye on the water temperature trends - a measurement that’s easy to do - and monitor your kelp in the early spring when biofouling organisms begin growing and harvest before they deteriorate your crops. Biofouling can severely deteriorate the quality of kelp if harvested too late, to the point that buyers will not accept it.