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A Thanksgiving View: It's the Little Things That Count!



Marsden and his son Bob head out annually to collect spat. Spat? What's that?


Now you now what spat is thanks to the above diagram image from Stewart and Arnold 1994.

So who is doing the counting>


According to their recent Facebook post, Hurricane Island Center for Science and Leadership is very excited to announce that they have been awarded funding from the Atlantic States Marine Fisheries Commission to delve deeper into our understanding of larval Atlantic Sea Scallops (Placopecten Magellanicus) as they partner with Bates College and Maine Center for Coastal Fisheries.


We can all be thankful for efforts like this to collect real data on this valuable part of our marine opportunities!


Read on to get a glimpse from Hurricane Island's post about what this work entails:


"When scallops are in their larval stage, they are free-floating through the water. When they find a suitable settlement habitat, they settle and metamorphose into the familiar form we know. The spat bags are filled with a rigid blue mesh, which mimics a habitat for larval scallops to land, or settle. They then grow in the bags and can’t escape the outer fine green mesh. What the spat bags look like before we put them in the water last fall. We mark the buoy with our phone number in case it gets lost over the winter. We retrieve the spat bags in the spring, usually in April and May. We just finished retrieving 12 of our spat bags that we deployed in Fall 2020 - we got back 11 of them and are gearing up to start sorting them! With the help of students and visitors we spend the summer counting how many scallops have settled in each bag and the other kinds of organisms we find along with the scallops. This involves sorting out the tiny 0.5-2 centimeter scallops from everything else in the spat bags, such as mussels, nudibranchs, and tunicates, which can be a time-consuming process. Luckily, there are often students and island visitors to help! We then count the number of scallops and record the presence and absence of other species. We can use this data to estimate the number of larval scallops in the water column. Since many of the spat bags were in the same place every year, we can compare changes between years. We can also compare between different locations. For example, the Lower Muscle Ridge area has been closed to fishing since 2013 as part of the Midcoast Maine Collaborative Scallop Project, so we might expect to see more spat in that area that is closed than the area that is fished. Learn more about the MMCSP here. The goal of a closure zone is to be a larval source for not only the closed area, but areas open to fishing nearby; a higher population of adult scallops in a small area could provide larvae for a much larger area and benefit both fishing and conservation goals. The Hurricane Island Research Team has been investigating the effect of the Muscle Ridge closure on spat in the area since 2013. .... We monitor changes in spat availability in the area from year to year by deploying spat bags inside the closure zone as well as directly north of the closure and directly south of it. This site is about a 45-minute boat ride from Hurricane Island. Spat bags in Muscle Ridge have been at similar sites inside and outside of the closure every year since 2013, so it is a good place to compare year to year.

..... Spat can travel 300-600 kilometers over 40-60 days, so spat in the Muscle Ridge area could be influenced by spat beyond Nova Scotia or Cape Cod. Local current patterns could carry spat from Mussel Ridge all over the Gulf of Maine, and spat from other areas could end up settling in this area. One way to tell if the scallop population on Muscle Ridge is enhancing the overall larvae supply in the local area would be to have a dive survey to assess the adult population, or plankton tows in the area while scallops are in the larval stage. We are also putting spat bags in other areas, such as around Hurricane Island, to see if these trends are the same throughout other areas of Penobscot Bay. ... Hurricane is excited to learn more about the scallop populations in the Gulf of Maine! Sources: Batchelder, J. P. 2017. Temporal changes in the larval Placopecten magellanicus population in a small-scale fishery closure area in coastal Maine, USA. Stewart, P.L. and S.H. Arnold. 1994. Environmental requirements of the sea scallop (Placopecten magellanicus) in eastern Canada and its response to human impacts. Can. Tech. Rep. Fish. Aquat. Sci.2005: 1-36. "


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