Rising ocean temperatures have a detrimental effect on the survival rate of baby lobsters and this in turn could have a major impact on related industries, a new study has shown.
Researchers at University of Maine have published a study in ICES Journal of Marine Science wherein they have shown how rising ocean temperatures and ocean acidification can hamper the survival rate and growth of lobsters respectively. While ocean acidification had almost no effect on survival of young lobsters, rising temperatures decrease the survival rate of baby lobsters substantially.
Jesica Waller, a graduate student at the Darling Marine Center at the University and lead author of the study, became interested in the research in 2014 while working as a lab technician with co-adviser David Fields at Bigelow. One of the reasons behind taking up the study was at the time Fields, who is a senior research scientist, was studying copepods, a small crustacean that lives in the open ocean, which have been found to migrate northward over the last 30 years owing to climate change.
“How copepods respond to climate change has important consequences for local fisheries in the Gulf of Maine,” says Fields.
Given the importance of lobsters to the local economy, Fields and Wahle mentioned how useful it would be if someone investigated possible effects of rising ocean temperatures and acidification on lobsters. Waller decided to take it on, utilizing Fields’ ocean acidification system at Bigelow Laboratory and tapping into Wahle’s extensive knowledge about lobsters.
The study by Waller is the first of its kind that focuses on how larvae of the American lobster will be affected by two aspects of climate change — ocean acidification and warming – she had to figure out how to go about carrying out the experiment.
Waller began her research in early June 2015 and for the two weeks from the start date she checked 10 egg-bearing female lobsters at the Darling Marine Center. The eggs were scooped out from the water and were taken to Bigelow Laboratory for Ocean Sciences in nearby West Boothbay Harbor. Waller revealed that all the eggs began hatching at once. During the experiment, Waller raised more than 3,000 lobster larvae, from the day they were hatched until the day they grew out of the larval stage, which takes about 30 days in current ocean conditions. She took measurements daily for a month, assessing their survival rate, development time, length, weight, respiration rate, feeding rate and swimming speed.
Lobster larvae reared in water 3 degrees Celsius higher in temperature, which is predicted by 2100 in the Gulf of Maine, struggled to survive compared to lobster larvae in water that matched current temperatures typical of the western Gulf of Maine.
“Really only a handful made it to the last larval stage,” says Waller. “We noticed it right from the start. We saw more dead larvae in the tank.”