Commercial fishermen in Maine will remember 2012 as a year when normal fishing routines did not apply.

For elver fishermen in Maine, 2012 provided a substantial boost to their income as the demand and supply of the juvenile eels soared to historical highs. For lobstermen, it was more of a mixed bag as they cumulatively caught a record amount (126 million pounds) but on average earned only $2.69 per pound for their catch, the lowest price they’d gotten in nearly 20 years. And for fishermen who caught squid it was a complete surprise because, historically, squid have not been found along the Maine coast.

The reason for all these unexpected developments, according to scientists and fisheries officials, is that water temperatures in the Gulf of Maine last summer were several degrees higher than expected. This caused elvers to show up in large numbers early in the 10-week season, lobsters to appear in shallow waters and shed their shells weeks earlier than expected, and squid to swim north around Cape Cod into the gulf.

According to several scientists at University of Maine and Gulf of Maine Research Institute, there’s more where these surprise developments came from. Changes in climatological conditions are expected to continue to affect commercial fisheries as species follow their preferred temperature ranges north or change the timing of their seasonal characteristics or migrations.

Exactly how and when these changes might manifest in terms of individual species is unknown, which scientists say is why fisheries scientists and regulators should take steps to offer fishermen better predictions and more flexibility in reacting to the changes. In a paper recently published in the scientific publication Oceanography, they make recommendations on how to make fisheries management more adaptive and effective.

“In order to sustain marine ecosystems, scientists and fishery managers also need to be able to rapidly adjust in response to abrupt changes in climate,” Katherine Mills, one of the UMaine and GMRI scientists who authored the paper, said Monday in a prepared statement.

The appearance of squid in the gulf is one example of why fisheries management in Maine needs to be flexible, scientists indicated in the paper.

“One of the surprises in 2012 was how quickly species and their fisheries responded to the intense warming,” they wrote. “During 2012, longfin squid — which are caught primarily in Rhode Island, New York and New Jersey — were present in Maine waters throughout the summer, and local fisheries and markets for this species developed within the season.”

Recommendations made in the paper include:

Developing scientific models that predict changes in climate and the resulting biological and economic impacts on marine ecosystems and fisheries.

Revising the permitting process to make it easier for fishermen to target species that may be new to the areas they fish.

Modifying existing management policies so regulatory agencies will be prepared for physical shifts in commercial fisheries.

Decreasing management reliance on past fisheries data that might become irrelevant to prevailing climatological and biological conditions.

While some management flexibility may be desired, there also is good reason to take preventative measures, according to lobster industry officials. Lobster is king among commercial marine fisheries in Maine, making up 65 percent of the $521.5 million total value of all the state’s commercial marine landings in 2012. Maine has approximately 5,500 licensed commercial lobstermen who caught nearly $339 million worth of lobster in Maine last year, while all the other commercially harvested species combined had a value of $182.5 million.

This dominance of lobster among Maine fisheries is why steps should be taken to help preserve the productivity of the species in the Gulf of Maine, according to several people who held a press conference in Portland earlier this week. Rick Wahle, a UMaine professor and co-author of the Oceanography paper, appeared July 2 at Portland Lobster Co. with lobster industry and environmental advocates to warn that climate change could adversely affect the Gulf of Maine lobster population.

“Warming ocean temperatures could shift suitable lobster habitat north,” Wahle said in a prepared statement. “On the one hand, warming may open new habitat that was historically too cold. On the other hand, warmer waters may threaten Maine’s lobster population by introducing predators or competitors from the south, and through other negative biological impacts.”

Wahle said the chemical properties of warmer water also could threaten lobsters’ health.

“The oceans absorb a significant amount of carbon, making the water acidic,” he said. “Acidic seas may harm lobsters’ ability to form adequate shells, although more research is needed on these effects.”

The Natural Resources Council of Maine said that the federal government should take action to mitigate the causes of climate change and to help protect the economic significant lobster has for the state.

“The fact that carbon pollution hurts Maine lobsters should be a concern to all Mainers,” Emmie Theberge, an official with NRCM, said in the joint statement. “The problems will only get worse until we take action at the national level to reduce carbon pollution. Today we continue to urge Sens. [Susan] Collins and [Angus] King to provide whatever support they can to reduce dangerous carbon pollution, especially from power plants. Maine’s future depends on it.”