Science for Everyone

Desperately Seeking Spat Bags

Some of the bags were completely covered in fast growing seaweed!

Dripping with muddy water and covered with tiny dancing skeleton shrimp, we spent the day searching for and hauling up lines of spat bags. Cait deployed them this past October, so they have been collecting scallop larvae for the past 9 months. A spat bag is constructed of 2 layers of mesh; the outside green layer having very small netting that only larval stage scallops can enter and exit through, and the inside blue layer with larger netting that they can attach and grow on. 5 bags are tied to a line with a cement block on one end and buoys on the other, suspending them at different depths throughout the water column. Soon, we’ll count all the scallop spat in the bags to gain an understanding of how many scallops are entering these areas and how much settlement might be occurring around Muscle Ridge. The bags don’t select for species, so we’re sure to find lots of little clams and mussels as well. 

Keeping the pile of spat bags cold and wet with ocean water

It takes a whole team of eyes to hunt down the right color in the sea of buoys.

Lobstermen generally don’t leave their traps out during the winter and you can see why. The buoys were harder to spot with the colors washed off and some of the bags looked more like we had undertaken seaweed aquaculture! Luckily our fantastic captain, Skip, had a knife handy to clean the outside of the bags as we hauled them up. Strong winter storms can also push the cement blocks across the ocean floor, far away from the GPS point where they were dropped, making it a challenge to find them again. In the end, we recovered 5 of the 12 lines, which luckily included all 3 lines that had the HOBO temperature loggers tied to them! To keep them wet and out of the hot sun, we covered them in burlaps sacks soaked in seawater. After multiple transfers in and out of the water, the spat bags made it on the boat out to Hurricane Island, where we’ll start counting those adorable little scallops.

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