Scientist Rick Wahle holds baby lobsters after a dive to gather data for the American Lobster Settlement Index.
Scientist Rick Wahle holds baby lobsters after a dive to gather data for the American Lobster Settlement Index.
Two new studies published in the scientific journal “Ecological Application” by University of Maine scientists based at Darling Marine Center, in Walpole, point to the role of a warming ocean and local differences in oceanography in the rise and fall of lobster populations along the coast from southern New England to Atlantic Canada. At the center of these studies is the American Lobster Settlement Index (ALSI), a long-standing shallow-water monitoring study serving as an important indicator of the strength of new lobster year classes repopulating coastal nursery habitats each year.

One study reports that the numbers of young-of-year lobsters populating shallow coastal nursery habitats each year, and temperature, provide a reasonably accurate prediction of trends in the lobster fishery some four to six years later. Researchers suggest the Gulf of Maine lobster fishery may be entering a period of decline; in effect a “cresting wave” of lobster abundance that may be heading northward in the region’s changing climate.

The second study underscores the importance of local differences in the oceanography of the Gulf of Maine for understanding where the lobster boom occurred. Scientists observed that an expanded area of thermally suitable habitat for larval settlement in the eastern Gulf of Maine may have helped drive and amplify the lobster boom in the region over the last decade. The cooler deepwater habitat may provide refuge for juvenile lobster from the negative impacts of ocean warming and buffer the Maine lobster fishery from similar decline as observed in Southern New England, but there are adverse effects of a warming ocean south of Cape Cod for other species.

Both articles can be found online at bit.ly/oppenheim2019 and bit.ly/goode2019.