Science for Everyone

Hanging Scallops by a Thread

Guest blog post by Research Assistant Bailey Moritz

Giving scallops the "ear" piercing

Our little guys are growing up! With many of the baby scallops from our spat bags now over 2 cm in size, it’s time for them to begin the next phase of scallop aquaculture. We visited the Darling Marine Center to learn from Maine Sea Grant’s Dana Morse about what that can look like. And what better way to do so than immerse yourself in the process and get muddy!

Completed scallop line ready for deployment

Ear-hanging is one method that can be used to grow scallops once they are about 2 inches across. A hole is drilled in the “ear” or wing of the shell, and gets threaded onto a rope that will be suspended in the water column. The technique comes from Japanese scallop farms, where operations are large scale and far more mechanized, as in this video. While it is a labor intensive process, researchers have been finding improved growth rates using the ear hanging method because water flow and space are unrestricted. Out on Hurricane, we will be using bottom cages for this coming year of growth, but may consider ear-hanging in the future.

Biofouling after several months in the water

Joined by others interested in pursuing scallop aquaculture, we boated around the corner to where Danas’ scallops have been growing in bottom cages, the same kind used for oysters. Upon hauling the cages up, it’s immediately clear how much fouling can occur. The bags were covered in tunicates, but they are easy to scrape off if you don’t mind the squishiness. We took out the larger scallops and brought them into the lab to be processed. The goal of the afternoon was to set up 4 lines of 60 scallops to deploy, each testing a different location of the drill hole. One ear is slightly larger than the other providing more stability for the hole while the other has a spot where drilling does not damage the shellfish’s mantle tissue. Dana will go back in 6 months to see if one method held up better than the others, and remeasure each individual to determine any growth rate differences. Ear-hanging is an exciting possibility for Maine waters. Dana is definitely leading the charge and it was awesome to see how doable it would be for Hurricane Island to carry out the technique ourselves next year!


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