ERI Funded Projects: Greta Nelson interning at a Shellfish Hatchery in Dennis, MA!

This past summer I worked as an intern at an oyster hatchery in Dennis, MA. The Aquaculture Research Corporation (ARC) is the largest producer of shellfish seed in New England, and sells both seed to shellfish farmers and market size shellfish to businesses across the country ( They also work with local towns to use shellfish in coastal protection strategies as well as improving the water quality of bays and harbors around Cape Cod. The hatchery for ARC is where the bivalves are spawned (sperm and egg are released into the water in order to reproduce), go through metamorphosis (mature to the point that they are no longer swimming larvae) and spend the beginning of their juvenile period. ARC spawns quahogs, eastern oysters, surf clams and bay scallops depending on the time of year.

Juvenile quahogs that have gone through metamorphosis and move with a large muscular “foot.”

As an intern, I was thrown into a range jobs. I worked mainly with the larvae: helping with spawning, keeping tanks clean, feeding algae and routinely checking the health of the bivalves. To check up on their health we looked at them under the microscope, looking at the shape of the shell and how it was developing and the color of their guts: if they are feeding well they have a dark almost black gut color. At this stage, they are so small you can see through their shells and see their entire inner anatomy! Bivalves are filter feeders that siphon micro-algae out of the water and they are fed continuously in the hatchery. This means that the other main job of the hatchery is to grow algae. The algae room is cool, bright and filled with huge bubbling tubes of dividing diatoms and flagellates, a mixed diet the hatchery has been perfecting for over forty years. I worked also with the brood stock, a carefully chosen collection of parent clams and oysters. Shellfish spawn in the summer when the water temperatures get warm; for this reason the tanks for the brood stock are carefully monitored within a specific temperature range. The trick to inducing a spawn is removing the clams to separate confined buckets, raising the temperature and adding a small amount of sperm to each bucket to trigger the spawn. Some of my favorite moments from this experience were watching the gametes come together under the microscope and following the cell division of the beginning of a baby oyster. I’d come in the next day and all the larvae would have already formed tiny shells and be swimming around like crazy.

Outside of the hatchery, I was able to go into the field with some ARC farmers and nursery technicians, working mostly with older oysters and seed out on the flats. Throughout the course of the internship I followed the entire life cycle of the shellfish, and subsequently gained a better understanding of how important these invertebrates are to our local economy and our bays. And I generally got more curious about these tiny creatures that live in the muck. In full honestly, what I most hoped to take away from this internship was a greater curiosity and knowledge about this place I have lived my whole life was. And it did just that. 

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