The Gulf of Maine is experiencing unprecedented warming, raising alarms about the future of the American lobster fishery, a critical economic driver in the region. Recent research out of the University of Massachusetts Dartmouth finds that increasing temperatures and acidification jeopardize developing American lobsters’ embryos and larval stages. It’s these departures that could heavily impact whether or not they ever make it. Gulf of Maine landings have exploded. At the same time, Southern New England’s lobster harvests have crashed, a clear sign that lobsters are moving north, seeking out cooling waters.
American lobster larvae develop externally on the underside of their mothers’ tails for 10 to 12 months before they hatch out. During this early, formative stage, they are especially sensitive to changes in their environment. Increasing temperatures in summer months can play a large role in their embryonic development. The larvae are a critical lifeblood of the marine fishery. If they hatch smaller due to increased temperatures, they may not make it. After all, the Gulf of Maine is warming faster than over 99% of the world’s oceans. Yet, researchers have made it the primary barometer in assessing these impacts.
Changes in Lobster Populations
In fact, the statewide American lobster fishery is worth nearly $2 billion dollars a year, and serves as the economic backbone for dozens of coastal communities. When you look at the lobster population dynamics in the Gulf of Maine, all isn’t as rosy as it seems. Landings in this region have increased dramatically in recent years. Southern New England has seen a pronounced drop in lobster catches. Seen through the new lens of climate change, this trend reflects lobsters’ northward migration to escape warming waters.
Growing evidence suggests that female American lobsters spawn in multiple batches while migrating through a continuum of marine habitats. This seemingly innocuous behavior is actually quite important to their survival, particularly as harshness in their environment continues to increase with our changing climate. The movement of populations towards cooler waters raises questions about the sustainability of fisheries in Southern New England and the overall health of lobster ecosystems.
The drop in Southern New England’s lobster landings should be a warning light of alarm oceanographic conditions. Based on research conducted three decades ago, the lobsters are running away from warming waters. This change would bring economic devastation to fishing communities that are economically dependent on their traditional fishing areas.
Impact of Temperature and Ocean Acidification
In a series of recent experiments, we have explored the impacts of temperature and ocean acidification stressors on American lobster embryos and larvae. Researchers exposed lobster eggs to water conditions that mimic those projected for 2060—specifically, a 4-degree Celsius increase in temperature combined with altered pH levels. The findings showed that although embryos surprisingly tolerate high levels of ocean acidification, elevated temperatures lead to strong and unique stress responses.
Each lobster embryo incubated under these warmer conditions hatched smaller in size. The size of larvae is critical to their survival. Larger larvae come with an almost guaranteed survival advantage against their smaller counterparts in the wild, including increased survival from predation and reduced competition for food resources. With embryos undergoing the most dramatic physical changes during the hottest summer months, carrying them through the harshest weather conditions is more and more difficult.
On top of this, the synergy between increasing temperature and acidification forms hyper compounded stressors that jeopardize the future of the species. The overall resilience of American lobsters under these changing conditions remains uncertain, necessitating further research into their adaptability and survival strategies.
Future Considerations for Lobster Fisheries
Scientists from Maine and beyond are collaborating on ongoing research efforts to understand how climate change affects American lobsters. Their results really drive home the point that we need to act quickly and proactively to maintain this important fishery. The rapid warming of the Gulf of Maine not only poses risks to lobsters but affects related marine ecosystems.
Fisheries management should be nimble enough to do so. To ensure the sustainability of the species, this could mean changing catch limits, changing fishing seasons, or even developing an aquaculture industry to bolster lobster stocks. Partnerships among practitioners of science, fishing, and fisheries management will be critical in devising adaptive strategies that respond to these environmental changes.