Science for Everyone

Scallops, and Clams, and Mussels, Oh My!

Post by Bailey Moritz, Scallop Research Intern

Mussel jackpot! We’ll put these guys back to grow bigger.

The dock has become my office. Since retrieving the spat bags in late July, I have been whiling away the hours, fog or shine, sorting and measuring the baby scallops in all 35 bags that we collected. Eventually, we will map the data to get a picture of where in Penobscot Bay scallop settlement is higher, which can inform fishery management policy. Even though my scallop count is a whopping 14,000 and counting, I can still say that baby scallops are adorable and surprisingly entertaining. These tiny guys are anywhere from 0.1 to 2 cm in height. By rapidly clapping their shell halves together, they can propel water and thus swim to the surface of the jar I collect them in. Check out Hurricane Islands Instagram for a great video of this phenomenon! My swimming jar of baby scallops has been an excellent show and tell for visitors and students pulling up on the dock. In addition to their cute little performance, juvenile scallop shells have colorful and varied patterns worthy of being called art.

An invasive form of encrusting tunicate forms orange and black mats on the mesh. The little white shapes are clams!

Baby scallops come in a beautiful array of colors and patterns that they’ll eventually lose in adulthood.

Mesh spat bags are not selective. Any larvae floating in the water column can enter the bag and start to grow. While there are upwards of 500 scallops in each bag, there are usually more than 5000 little clams filling the bag as well. Thank goodness I’m not counting clams! The spat bags came from different locations in Penobscot Bay, and you can tell. Each spat bag displays distinct characteristics from the others. One might have lots of healthy juvenile mussels hanging on tight with their byssal threads. Another may have only larger scallops compared to bags with handfuls of practically unseeable small ones. A number of bags contain starfish, thought to be a predator to the scallop, which might be the cause behind a number of empty, crushed shells. I have seen 7 species of beautiful sea slugs, called nudibranchs, and am now well acquainted with tunicates and sea squirts that find the thick blue mesh a perfect point of attachment. I won’t say the number of times I’ve accidentally squirted myself (or others) in the eye trying to peel them off the bags.

Over the course of the past month witnessing the ebb and flow of the tides from my workspace, I have come to appreciate the diverse and unique ecosystem that is a spat bag. What may at first appear to be a mess of muddy shells, shrimp, and slime, actually holds a snapshot of a coastal marine world in an early stage of growth. I still have a few more spat bags to pick through. But with the dock as my office and swimming baby scallops to keep me company, I really can’t complain.

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