“I’ll have the lobster”: How Climate Change Affects the American Lobster and its Industry

By Maggie Erwin

It is a familiar summertime sight: large plates boasting bright red lobsters atop beds of lettuce and carrots; tourists gleefully carrying rolls to their picnic tables, packed densely with lobster meat and mayonnaise; customers lining up at the seafood markets, on the docks, or at their favorite lunch joint to enjoy the daily catch. The impact of climate change could relegate these idyllic scenes to memories of summers past.

The American lobster, Homarus americanus, is an iconic species in coastal towns along the Northeastern coast of the United States. In fact, lobsters are the highest valued species in the nation’s commercial fisheries, with earnings of around $684 million in 2018¹. Lobsters are woven deep into the fabric of the New England economy, with up to 92% of the nation’s lobster coming from the Gulf of Maine, where fishermen and the entire supply chain along the coast rely on the species for their livelihoods.

Like many other marine species, the American lobster is faced with several challenges due to climate change, including warming waters that accompany the overall increased temperature of the planet. In the Atlantic Ocean, this is occurring more rapidly in areas where lobsters are most abundant, such as the Gulf of Maine. Southern New England fisheries have been impacted by this rise in temperature as lobsters are forced to move northward.

Researchers and lobstermen are recording temperature fluctuations in these areas so that the industry can better prepare for the future. Bruce Fernald, a lobsterman from Little Cranberry Island in Maine, works with scientists to record temperature changes using a temperature probe placed in lobster traps.

“You’re looking for these water temperature fluctuations because they’re so sensitive to what they [lobsters] do in their life, whether they’re feeding, mating, or shedding their shells,” explained Fernald.²

Without the option of changing their environment, lobsters are forced to use other coping mechanisms, as observed by fishermen and researchers. Many lobsters have begun to move to deeper waters where it is cooler. For fishermen, this means travelling greater distances to catch lobsters, which increases the energy demand of fishing boats and releases more carbon dioxide. Members of the lobster industry and research organizations are working hard to adapt to these changes as ocean temperatures rise.

An additional mechanism by which climate change threatens lobsters involves the ocean’s role as a reservoir for atmospheric carbon dioxide. As concentrations of carbon dioxide in our atmosphere rise, oceanic concentrations also increase. This process changes the chemistry of the ocean, making it more acidic, through a process known as ocean acidification. The rate at which surface seawater is becoming more acidic is 50% higher in the North Atlantic than in the rest of the world’s oceans³ as a result of large temperature variability as well as the reduced buffering capacity in this region.

Acidic waters are dangerous for lobsters and other marine species that form their shells through the deposition of calcium carbonate, a mineral known commonly as chalk and limestone. Many species of mollusks, corals and crustaceans rely on calcium carbonate for their growth and protection, but the availability of carbonate ions needed to build calcium carbonate decreases with ocean acidification. Thus, ocean acidification resulting in less carbonate makes it harder for calcifying organisms to construct their shells.

If you have ever eaten lobster, you may be familiar with the arduous process of cracking open the shell. This usually involves pliers of some sort and lots of napkins. It is never an easy process, which is nature’s design. Crustaceans, the taxonomic group that includes lobsters, rely on hard shells comprised of four layers⁴ for protection against predators, diseases, and other environmental threats. Within the shell, a complex sugar known as chitin, similar to the keratin in human fingernails, forms a strong matrix that supports the exoskeleton. Within this matrix, lobsters secrete these calcium carbonate crystals, fortifying their shell.

Studies have shown that lobsters exhibit a complex response to ocean acidification, one which involves several innately linked biological processes, such as immune function and growth. In these studies, researchers have discovered that when larval stages of lobsters are exposed to acidified conditions, there is a decrease in the mineral content of the shell⁵, a decline in growth rate⁶, and a weakening of immune function⁷. In one study that focused on the early stages of lobster larvae exposed to acidified conditions (pH of 7.7), researchers discovered that the length of the lobster’s shell was shorter than under control conditions (pH of 8.1) and that it took longer for the lobsters to moult. Another study illustrated similar conclusions, revealing that lobsters exposed to more acidified conditions (highest amount of carbon dioxide in seawater) took longer to moult⁸, were smaller, and were more affected by shell disease when compared to larvae raised under ambient pH⁹. Shell disease, which contributed to the infamous 1999 lobster die-off that devastated Long Island Sound fisheries, poses an additional concern with regards to lobsters’ ability to fight off sickness amidst other threats. Many experts believe lobsters will exhibit a variable response, and that their ability to form their shells under more stressful conditions may come at an energetic cost, one which affects immune function, reproduction, and growth.

While the specific way in which ocean acidification will affect American lobsters is still unclear, researchers agree that the overarching challenge from global climate change will continue to threaten this valuable species. Additionally, these altered environmental conditions may also impact fishermen’s livelihoods and the vast market derived from the sale of lobsters along the Northeast Mid-Atlantic. Michael Tlusty, associate professor of Sustainability and Food Solutions at the School for the Environment at the University of Massachusetts, Boston, said, “The greatest threat right now [facing the American lobster industry] is climate change.” While we wait for ongoing and future research to reveal how lobsters will respond to changing ocean chemistry, it is imperative that industry stakeholders, scientists, fishermen, and policy-makers work together to find sustainable ecological solutions as soon as possible.

Fortunately, this work is already underway. Bruce Fernald and other lobstermen have been working with scientists for over twelve years through climate change workshops hosted annually in Maine. “One of the guys is talking about algae blooms,” Fernald remarked about the workshops¹⁰. “Then, there are people that talk about stock assessment and all the lobsters. We are observing any climate change stuff that we might see, whether it’s water temperature or tides or currents, whatever. We’re observing and comparing with the scientists. So, it’s a pretty good session.”

Research is also being conducted through the National Sea Grant American Lobster Initiative, a large-scale collaborative effort between scientists, fishermen, and industry members to better understand how lobsters will respond to changes in their environment and to build resiliency within lobster fisheries.¹¹ These collaborative efforts, as well as national goals in reducing carbon dioxide, and personal and local attempts to reduce one’s carbon footprint, are all important ways by which we can reach sustainable solutions in order to support and protect this iconic species. Next time you are enjoying a lobster roll, consider how you can make a difference through thoughtful choices, voting, and everyday actions to reduce waste. As the threat of climate change becomes more palpable, we must not lose the will to make a change, not only for lobsters but for communities everywhere and our home, planet Earth.

About the author:

Maggie Erwin is a current student at Wellesley College studying Geosciences and English. This work resulted from an undergraduate research opportunity at MIT under the supervision of Dr. Carolina Bastidas, a research scientist at MIT and contributor to the American Lobster Initiative by the NOAA National Sea Grant College Program, and Dr. Katrin Monecke, Associate Professor of Geosciences at Wellesley College.

References & Citations

1. 2018 A strong, Successful Year for U.S. Fishermen and Seafood Sector | National Oceanic and Atmospheric Administration (n.d.). Retrieved March 11, 2021, from https://www.noaa.gov/media-release/2018-strong-successful-year-for-us-fishermen-and-seafood-sector
2. Fernald, Bruce Oral History Interview, March 1, 2018, by Galen Koch, Page 3, Voices from the Fisheries. Online: https://voices.nmfs.noaa.gov/sites/default/files/2018-11/fernald_bruce.pdf (Last Accessed: May 5th, 2021).
3. IPCC, 2018: Global warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [V. Masson-Delmotte, P. Zhai, H. O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J. B. R. Matthews, Y. Chen, X. Zhou, M. I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, T. Waterfield (eds.)]. In Press.
4. Luquet, G. (2012). Biomineralizations: Insights and prospects from crustaceans. ZooKeys, 176, 103–121. https://doi.org/10.3897/zookeys.176.2318
5. Arnold, K. E., Findlay, H. S., Spicer, J. I., Daniels, C. L., & Boothroyd, D. (2009). Effect of CO2 related acidification on aspects of the larval development of the European lobster, Homarus gammarus (L.). Biogeosciences, 6(8), 1747–1754. https://doi.org/10.5194/bg-6-1747-2009
6. McLean, E., Katenka, N., & Seibel, B. (2018). Decreased growth and increased shell disease in early benthic phase Homarus americanus in response to elevated CO2. Marine Ecology Progress Series, 596, 113–126. https://doi.org/10.3354/meps12586
7. Harrington, Amalia & Harrington, Robert & Bouchard, Deborah & Hamlin, Heather. (2020). The synergistic effects of elevated temperature and CO 2 – induced ocean acidification reduce cardiac performance and increase disease susceptibility in subadult, female American lobsters Homarus americanus H. Milne Edwards, 1837 (Decapoda: Astacidea: Nephropidae) from the Gulf of Maine. 10.1093/jcbiol/ruaa041.
8. Keppel, E. A., Scrosati, R. A., & Courtenay, S. C. (2012). Ocean acidification decreases growth and development in American lobster (Homarus americanus) larvae. Journal of Northwest Atlantic Fishery Science, 44, 61–66. https://doi.org/10.2960/J.v44.m683
9. McLean, E., Katenka, N., & Seibel, B. (2018). Decreased growth and increased shell disease in early benthic phase Homarus americanus in response to elevated CO2. Marine Ecology Progress Series, 596, 113–126. https://doi.org/10.3354/meps12586
10. Fernald, Bruce Oral History Interview, March 1, 2018, by Galen Koch, Page 3, Voices from the Fisheries. Online: https://voices.nmfs.noaa.gov/sites/default/files/2018-11/fernald_bruce.pdf (Last Accessed: May 5th, 2021).
11. Harrington, Amalia, et al. “A Fishery in a Sea of Change.” ArcGIS StoryMaps, Esri, 4 May 2021, storymaps.arcgis.com/stories/f50bd80b84d349048e9d814769dc29cd.
12. Sartore, Joel. “An American Lobster Photographed in Lincoln, Nebraska.” National Geographic, www.nationalgeographic.com/animals/invertebrates/facts/american-lobster.
13. Snyder, Brian. “A Lobster Sits in a Holding Bin before Having Its Claws Banded Onboard the Lobster Boat ‘Wild Irish Rose’ in the Waters off Cape Elizabeth, Maine August 21, 2013. Sweden Wants a Blanket Ban of Live North American Lobster.” The World, 2016, www.pri.org/stories/2016-03-29/swedes-want-north-american-lobster-out-and-americans-are-fighting-back.