Lobster is an important food source for other marine organisms and humans. In 2008, the U.S. landed 81.8 million pounds of lobster, valued at $306.2 million. The American Lobster fishery is one of the most valuable fisheries in the Eastern U.S and it’s especially important to Maine, which accounts for the majority of total U.S. landings and is the state’s most lucrative fishery—generating 70% of the state’s 2009 commercial fishing value ($228 million).

©NOAA

However, the future of this important resource is uncertain. The Southern New England range of the lobster is already experiencing decline, likely from warmer waters (see, Climate Change Suspected for Lobster Decline in Southern New England Stocks). According to a 2009 federal report, “Global Climate Change Impacts in the United States,” this region (specifically Rhode Island & Buzzards Bay in Massachusetts) suffered a sharp decline in the late 1990s due to a temperature-sensitive bacterial shell disease. The report states that, “[c]urrently, the southern extent of the commercial lobster harvest appears to be limited by this temperature-sensitive shell disease, and these effects are expected to increase as near-shore water temperatures rise above the threshold for this disease.”

According to the Atlantic States Marine Fisheries Commission’s (ASMFC) fisheries management plan, which details the decline of Southern New England lobster, water temperature is critical to lobsters. The plan cites scientific research showing that prolonged exposure to temperature over 20°C (68°F)”causes respiratory and immune system stress, increased incidence of shell disease … and suppression of immune defenses.”

A recent Audubon Magazine article, “Seafood for Thought: How Might Climate Change Affect American Lobsters,” discusses the lobster in Long Island Sound. The writing is on the wall, says Richard Wahle, a research associate professor at the University of Maine’s Darling Marine Center, “…the Sound will become no longer hospitable for lobsters.”

Analyses also suggest that warmer water expands suitable nursery grounds for larvae and increases lobster growth rates, allowing juveniles to mature faster. This may benefit northern lobster regions such as the Gulf of Maine or Gulf of St. Lawrence in Quebec waters. However, a report (“Maine’s Climate Future”) from the University of Maine warns that warmer water benefits may be offset by predator increase. As water warms, southern fish communities could start expanding northward, swelling predator numbers. According to the Maine report, “Fishermen are already noticing significant changes in the lobster fishery, including altered growth and migration behavior.”

Ocean acidification, caused by too much carbon dioxide in the ocean, may be another hazard to lobsters. While lobster impacts are still unclear, rising ocean acidity could make lobsters more susceptible to shell disease and affect overall shell-building capability.  

While the exact impact on lobsters from a changing climate is still unclear, southern ranges are already feeling the effects. Changes are very likely in store for this species and the fisherman who depend on them.

Online Resources:

• Jacobson, G.L., et al. “Maine’s Climate Future: An Initial Assessment.” University of Maine. 2009.
• Leibach, Julie. “Seafood for Thought: How Might Climate Change Affect American Lobsters,” Audubon Magazine, 20 July 2010
• Atlantic States Marine Fisheries Commission. Recruitment Failure in the Southern New England Lobster Stock, 17 April 2010
• WWF website: Impact on Species, American Lobster

WWF Climate Change Blog:

• Climate Change Suspected for Lobster Decline in Southern New England Stocks, 20 June 2010.
• New England Fisheries Impacted by Climate Change & Dwindling Fisheries, 28 July 2010
• Fisheries of Northeast U.S. Continental Shelf Shift as Climate Changes, 22 Nov. 2009.
• Eastern Oysters in Jeopardy from Ocean Acidification,  20 June 2010.
• Ocean Acidification section.