We all know that the Gulf of Maine is warming fast, helping push lobsters north to cooler waters. (They’re already disappeared from Long Island Sound.) A new UMaine study finds that even if they stick around, their habits change. Whole article in phys.org is here.
For decades, the vast majority of adult lobsters resided in boulder shelter habitats. This knowledge helped inform longtime conservation efforts and regulations within the more than $740 million fishery.
A team of UMaine scientists, however, found that from 1995–2021, occupancy of boulder habitats dropped 60%. Meanwhile, the number of lobsters residing in sediment or featureless ledge habitats, both of which have little to no geological features to use as shelters, increased 633% and 280%, respectively. Lobster population density across all types of habitats declined too, meaning they are fewer in number and their populations are more spread out.
While overall population density has declined, the mean size of an adult lobster was greater in 2021 than in 1996. According to the study, the increase in mean size is partially the result of fewer juvenile lobsters residing in these habitats. While lobsters in the Gulf of Maine are now larger, the team observed that the majority, or 93%, were still smaller than 83 millimeters, the minimum legal size to be caught and sold—a promising sign for the fishery.