American lobster population, habitat preferences shifting, study finds
October 18, 2024

American lobsters along Maine’s coast have relocated to new habitats, while the population simultaneously shrunk in abundance and grew older, according to a new study by University of Maine researchers.

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.

Water temperatures increased nearly 3 degrees Celcius from 1995-2021 across these habitats, according to researchers, showing how lobsters and their habitats are changing with the climate. Kelp abundance declined across lobster habitats, while diminutive algal turfs — small green mats containing multiple species of algae — increased.

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