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You may dimly remember from high school biology class  that shellfish, surprisingly enough, do not begin life with shells. Eggs and sperm are released into the sea and the fertilized spawn is a free-swimming little creature. These  scallop larvae develop a foot and protective shell as they mature. When the free swimming larvae settle, they are called spat. 

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Dana Morse photos

The Brewers suspend in the water column spat bags which collect the spat in late summer or early fall and the juvenile scallops then grow in protective nets. The beauty of the modest scale of this style of aquaculture is that local knowledge enables the would-be farmer to choose a site that is not only ecologically suitable but that does not compete with lobstering — or sailing. 

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Water currents bring in phytoplankton that feed the developing scallops and the same currents carry away waste products. Filter-feeding mollusks are famous for cleaning our waters. They have a system which bypasses their digestive tract and expels rejected particles and detritus as what is properly called pseudofeces. Wrapped in mucus and dropped to the sea bottom this becomes available as nutrients for benthic life, our sea bottom dwellers.


When they are a year or so old the petite scallops, often called princesses, are ideally suited for little snacks delicatly subtle in flavor. At two years-and-some, the mid-sized scallops have a particularly fine flavor, preferred for many dishes. Chefs used to using only wild-caught adductors often order the largest three or four year old size. As in tree rings, one can more or less read stresses and years on the scallop shells. 


The biological, chemical, and physical characteristics of an environment contribute to the taste of the product as vintners have discovered — what they call terroir. This is not less true for the sea. Call it meroir. Penobscot Bay sea products share a distinctively superb taste.  

Farmed vs Wild
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Dana Morse photo

Divers and fishing boats rigged with heavy dragging equipment annually head out to fish our waters. In Maine the season for wild scalloping usually runs from about December 1 to mid-April. If weather allows good fishing days, a region may have to be closed for the season when the allowable quota of the harvest of the wild scallop population is reached. Since wild-caught mature scallops — those with shells that measure four inches across or larger — are shucked at sea and only the meat, the adductor muscle, is brought ashore and sold, the public is not exposed to biotoxin risks from them.  This is the reason that whole or roe-on scallops MUST be purchased through a certified dealer operating where environmental conditions are scrupulously monitored. Under no circumstances whatsoever should one assume that it's safe to eat any part of large wild caught scallops except the adductor muscle.

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The Future of Aquaculture—the 2020 Vision

Scallops of various species exist in all the oceans of the world. In the past, scallop populations around the globe collapsed due to various factors including overfishing. Regulations to save the scallop by wild harvesting only large scallops and marketing only the adductors have resulted in cooks forgetting how the whole scallops were once traditionally prepared. Now that world-wide scallop aquaculture has developed, we have another approach to make sure our scallop populations can be sustainably harvested. Neither wild scallop fishing nor aquaculture need be in competition with each other. Each has a different effect on the environment and results in a different product for our table. We are learning that there is strength in diversity!  

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This exhibit at an aquaculture facility in Japan shows a variety of techniques and different nets that are anchored in the water column. Based on how aquaculture is developing in other countries, we can expect Maine aquaculture to parallel how sea farming in general happens these days. There will be a question of scale: small, rather boutique operations as well as large quite industrial ones. New methods of mechanization in raising and processing will develop accordingly. Demands of the niche market will evolve. Here on the coast of Maine we are exceptionally fortunate to have fishermen with vast stores of local knowledge who are also flexible enough to explore new ways of doing things. 

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So you say you want to grow your own scallops? The species that is currently being farmed here is our native Plactopecten magellanicus, the Atlantic deep-sea scallop, found from North Carolina to the Gulf of St Lawrence. Will you use hatchery-produced “seed” or natural “seed” collection? Adult scallops have shed their eggs and sperm into the sea. The larvae develop and eventually settle on fine mesh the would-be farmer has provided. The settled juveniles are eventually transferred to what are called spat bags where they grow to the right size for taking up life in a variety of different 'real estate' options. There are so-called pearl nets, lantern nets and even seeding on the sea floor. Depending on the size destined for market, the scallops spend a year or more happily dining on phytoplankton in the water column. 

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You will make decisions about investing in such aids as drills for ear hanging, washing and sorting machines and other emerging technologies.

You may have to improvise. For example you may have to forge your own specially-designed anchors to hold the gear in the location you have leased. Perhaps you will devise a submerged horizontal longline from which to hang your nets and mark the set up with a line of buoys. Or maybe you will try suspending lines of scallops hung by their ears —  that little shell flap.

Here's a good article about managing the tech side:

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Next you need to be certified which means that you send both scallops and water samples at intervals to the DMR (Department of Marine Resources) laboratory to be tested for toxins. The frequency of testing is increased in the warm months as conditions in the environment are more likely to become favorable for the organisms which produce the toxins. Rigorous and costly procedures. Ah, yes indeed, for everything there is a season — and a reason. 


You share knowledge with those around the world developing aquaculture. 

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Farm fresh? Local? Natural? Low tech? Low risk? Maybe not quite all of these, but aquaculture in Maine offers a very good set of options for us to be exploring for our future.

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Bo Hoppin (Executive Director, Hurricane Island Center for Science and Leadership) gets together with researchers, scientists, and fishermen of Penobscot Bay to discuss the future of marine and aquaculture research in Maine and beyond. Panelists include Marsden Brewer (Sustainable Scallop Farmer, Pen Bay Farmed Scallops), Phoebe Jekielek (Director of Research, Hurricane Island Center for Science and Leadership), Madison Maier (Aquaculture Manager, Hurricane Island Center for Science and Leadership), Dr. Nichole Price (Senior Research Scientist, Bigelow Laboratory for Ocean Sciences), and Dr. Bob Steneck (Professor of Marine Sciences, University of Maine Orono and Hurricane Board Member). This was a Zoom webinar and was previously recorded on July 29, 2020.

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