A number of local research teams are trying to predict how climate change will impact our local fisheries, so that fishermen and communities that rely on fisheries can be ready to adapt and avoid being caught off guard in the future.
Take, for instance, the lobster fishery in Maine. We had an event in 2012 where anomalously warm temperatures caused lobsters to molt early and nearly simultaneously. The ensuing glut and price crash forced people to think about the economic consequences climate change can have on the fishery.
Dr. Andy Pershing, chief scientist at the Gulf of Maine Research Institute (GMRI) is working with Dr. Kathy Mills (also at GMRI) and Dr. Nick Record of Bigelow Laboratory for Ocean Sciences to predict the timing of the lobster molt. The goal is to provide a tool that could help the industry avoid another economic crisis like it experienced in 2012. Based on NOAA’s temperature forecast, very warm spring water temperatures are predicted in the Gulf of Maine this year. Another very warm spring could result in another early molt.
Pershing says: “A simple linear model can do a good job of predicting when landings start to increase. This uptick in lobster landings usually happens in July and we can estimate the date using March and April temperatures.”
The group plans to start issuing forecasts this March on the predicted timing of the molt, and the goal is to have the forecasts out as early as January in the coming years.
Another effort, led by Dr. Rick Wahle at UMaine’s Darling Marine Center, is using a long-term data set, known as the American Lobster Settlement Index (ALSI), as a predictor of future abundance of lobster. Wahle and Dr. Bob Steneck (also at the Darling Marine Center) began ASLI in the Midcoast in 1989. Now, there are sampling sites all the way from Rhode Island to Newfoundland.
This international collaboration is unprecedented in that there is no other consistent survey methodology for lobsters stretching across countries over such a long time period anywhere else in the world. Sites in each region are sampled in the fall for newly settled lobsters, either by scuba diver-operated suction sampling (essentially hand-held, underwater vacuums) or collectors that mimic suitable settlement habitat which are deployed and retrieved by boat.
Using the “settlement index,” or the average number of baby lobsters per square meter, you can look ahead six or seven years and get an indication of the number of lobsters that will be reaching harvestable size. Wahle and his colleagues (of which there are many in this international effort) have had good success in predicting future abundance in their Rhode Island sites. Despite the dismal story of declines in Rhode Island due to shell disease, Wahle was heartened by the success of the predictive capabilities of the settlement index.
Wahle and UMaine graduate student Noah Oppenheim are determining if the settlement index can be a good predictor in other regions, particularly eastern Maine where the trajectory of lobster abundance is just the opposite of southern New England. According to Wahle, “around the year 2000 in eastern Maine, we started to see newly settled lobsters showing up in areas that used to be devoid of settlers. From 2005-2010 things really started to ramp up and soon after that they started to see harvests go through the roof.”
Interestingly, in 2013, there was a dramatic decline in settlement from Massachusetts through Nova Scotia—record lows across the board. This decline was followed in 2014 by a gulf-wide increase.
“This is where it is interesting to look at the environmental drivers of these fluctuations,” says Wahle. He and Pershing and other collaborators have found that temperature and wind are both important factors in determining settlement. If prevailing winds, which are determined by the jet stream, are onshore, then they favor inshore settlement.
Predictive tools can help but are not a crystal ball.
“We can plan for events we can predict, but with climate change, we have been dealt surprise after surprise,” says Steneck. He projected landings in eastern Maine to rise all the way back in 2001, but what no one predicted was the onset of shell disease in southern New England. Expecting the unexpected and possessing a willingness to adapt is a necessity. Without a doubt, only with buy-in from the industry can the predictive models realize their full potential, which is to be useful for management and to help the businesses that depend upon the fishery.
Updates on the status of these forecasting tools will be presented at the Maine Fishermen’s Forum in Rockland on March 6.
Dr. Heather Deese is an oceanographer and the Island Institute’s vice-president for strategic development. Dr. Susie Arnold is an ecologist and marine scientist with the organization.