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The Biggest Threat Facing Maine’s Lobsters

By Sophie Lewis

Postcard depicting the defunct Mellow Lobster company

It is no secret that lobsters are crucial to what makes Maine, well, Maine. More than a marketing symbol on postcards, lobsters are also a vital part of Maine’s economy and identity. Lobsters entice millions of tourists to visit Maine every year. People come from all over the world to get lobster fresh off the boat. The lobster industry in Maine employs 3,000 full-time lobstermen and another 2,000 part-time. The industry contributes $339 million to Maine’s economy. Maine's economy, culture, and shoreline would be drastically different without lobster.

Despite the evident benefit of lobsters in Maine–both to Maine’s economy and identity– rising sea temperatures in the Gulf of Maine have become increasingly threatening to lobster populations since the beginning of the 21st century. Since the early 1980s, sea surface temperatures in the Gulf of Maine have increased 0.86 degrees Fahrenheit per decade. Although this sounds insignificant, it is three times more than the average warming of the world’s oceans. Research has found that higher ocean temperatures require lobsters and other cold-blooded animals to use more energy for breathing, which leaves them less energy for growth, feeding, and reproduction. There has also been research linking warmer water temperatures to a condition that causes female lobsters to molt more frequently, making them more vulnerable.

This is because the waters off of these coasts have become too warm for the lobsters to live in and reproduce. The impact of the temperature went unnoticed for some time, where increasing water temperatures in the Gulf of Maine were not always a threat to the lobstering industry, even prompting a lobster boom. From 1985 to 2014 there was a 500% increase in lobster abundance on the coast of Maine, where water temperatures increased drastically between 1980 and 200 as cited by scientists as a source of the lobster boom. The rising temperatures had, and continues to have, negative impacts on other aquaculture and fishing industries in Maine such as shrimp, cod, and scallops, causing Maine fishermen to have a growing dependence on lobster alone for their livelihoods. Despite lobsters flourishing in the increasingly warm waters, scientists project that the gulf will become too hot to facilitate reproduction. As acknowledged, lobsters are cold-blooded and require cooler water in order to conserve energy. Therefore, increasing temperatures in the gulf cause the lobster population to plummet in the near future.

For now, Maine is the sweet spot–temperature-wise–for these cold-blooded creatures, but this will not last forever. A 2018 study found that in the next 30 years the gulf’s lobster population could fall to 40-62% of its current volume across all regions. Furthermore, the National Oceanic and Atmospheric Administration Fisheries suggests that the warming that will take place in the ocean on the coast of Maine in the next 80 years will lead to the only suitable places for lobsters to be the deeper and colder areas of the Gulf of Maine: further isolating lobsters from popular lobstering areas off the coast of Southern Maine.

The reason for the dramatic change in temperature, like many environmental disasters contemporarily, is climate change. Sea temperatures are rising all over the world, due to release of carbon into the atmosphere, but its consequences are felt more strongly on the Gulf of Maine. Heat radiated from the Earth’s surface is being prevented from going into the atmosphere by the rising amount of greenhouse gasses there. As a result, most of this excess heat is passed into the ocean, raising its temperature. Over 90% of the warming that has happened on Earth in the past 50 years has been in the ocean, and the increased release of carbon increases water temperatures while also disrupting the Atlantic Conveyor Belt, which sends warm water north through the Gulf Stream and cold water south through the Labrador Current. The effects of rising temperatures on this current are evident in melting of glaciers, causing more freshwater to flow into the North Atlantic, slowing down the Labrador Current, and causing more warm water into the Gulf of Maine and raising temperatures at such a higher rate compared to the rest of the world.

The question of this issue then becomes how Maine can protect their lobster populations and industry. On the state level, Maine has already begun to implement regulations protecting the lobster population. These regulations usually fall into two categories: sex regulations and size requirements. For example, if a female lobster is ‘berried’ or carrying eggs, or if they were at one time, then they must be released back into the ocean. Similarly, fishers must measure the length between a lobster's eyes and their tail to see if they are too big or too small. If that is the case, they must be released back into the ocean. These regulations have done great work protecting Maine’s lobster populations, but rising ocean temperatures will make these regulations inadequate at protecting lobsters.

Knowing this, on December 1st 2020, Maine released a four-year climate plan with special attention to lobster preservation. The plan, titled Maine Won’t Wait, outlines four specific goals to confront climate change including reducing carbon emissions, producing more energy from renewable sources, protecting our natural resources, and avoiding the cost of inaction. It is under this category that lobster population related efforts fall. The plan outlines that if the lobster abundance declines by 2050 as it is projected, Maine’s cumulative GDP would fall by about $800 million over the next 30 years. In addition to the plan, in 2019 Governor Janet Mills signed legislation that required Maine’s greenhouse gas emissions to decrease by 45% by 2030 and at least 80% by 2050. Mills has outlined ample goals to try to protect the lobster industry and other vital parts of Maine’s economy and general health, but there needs to be significant work done to meet these goals. As with all aspects of climate action, goals are a great starting point but it is action that will achieve these goals and combat the effects of climate change.

Of course, this assumes that action can be done by the state suffering the harms of climate change. In the case of Maine’s lobster industry, the number one cause of rising ocean temperatures are coal burning power plants outside of New England. Even though Mills’ plan to reduce carbon emissions in Maine is vital, it will not be enough to protect Maine’s lobsters because of the externalities caused by other states. The best way to protect Maine’s lobsters is to have change on a national level.

Section 112 of The Clean Air Act, that addresses air pollutants, needs to be developed to further reduce carbon pollution from power plants in order to not only protect Maine’s natural resources, as well as their lobster industry and population.


Works Cited

Dahlman, R. L. A. L. (n.d.). Climate change: Ocean heat content. NOAA,over%20the%20past%20few%20decades.

Greenfield, N. (2019, August 19). Could the climate crisis spell the end for Maine lobster?. Be a Force for the Future.

Gulf of Maine Warming Update: 2022 the second-hottest year on record. Gulf Of Maine Research Institute. (2023, February 15).,per%20decade%3B%20Figure%201).

Maine Climate Council. (2020). (rep.). Maine Won’t Wait.

O’Brien, M. (2019, September 18). What rising temperatures in the Gulf of Maine mean for the state’s lobster industry. PBS.

Press, A. (2023, February 6). In Maine, regulators pursue new lobster regulations with stricter size limits. Fox News.

Rosenthal, Z., & Ambrose, K. (2022, September 11). The Gulf of Maine is simmering, but its lobsters seem fine - for now. The Washington Post.

Theberge, E. (n.d.). Help Maine Lobsters Keep Their Cool. Natural Resources Council of Maine.


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