ROCKPORT, Maine — A brief, unvarnished rant by long-time lobsterman and fishery leader Dave Cousens closed out a session Thursday on ocean acidification at the Maine Fishermen’s Forum.

It drew applause, but owing to editorial standards, the exact words can’t be repeated here.

In essence, Cousens said the cause of problems like the well-documented rise in ocean temperatures and the equally well-documented drop in ocean pH — meaning the waters are becoming more acidic — is known. And the solutions, while difficult, also are known.

Describing politicians as “morons,” he said it was clear that carbon emissions had to be limited to address climate change.

The focus of the session was on how more acidic ocean waters are impacting shellfish like soft-shell clams. Shells are getting thinner, and even clam behavior in response to attack is observed to be changing in the new environment, panelists and participants reported.

As carbon dioxide increases in the atmosphere, it gets absorbed into the ocean, which in turn causes the pH to change. How a more acidic ocean coupled with warmer ocean waters has and will affect shellfish and other marine life is largely unknown, panelists said.

But what is known is that a warmer ocean has meant that predators and pathogens not seen before in the Gulf of Maine are migrating north.

Clams, said Tim Bowden of the University of Maine,  “are going to be presented with a new set of pals hanging around.”

Also known is that a more acidic ocean is causing soft-shell clams to have shells that are 30 percent to 40 percent thinner, said panelist Mark Green of St. Joseph’s College of Maine.

That thin shell makes them vulnerable to attacks from green crabs.

When climate and chemistry change, “there’s always going to be winners and losers,” Green said.

Responding to a question, Larry Mayer of the University of Maine’s Darling Center said that 90 percent of the Gulf of Maine is salt water, while 10 percent is fresh water that flows from rivers and streams. But that fresh water is 100 times more acidic than the salt water, he said.

One fix that was discussed — useful in clam beds, though not beyond — is grinding up empty clamshells and returning them to the beds, which counteracts the acidic environment in that small area.

“You do it over a series of years, and slowly you can increase the production of those beds,” Green said. “You’ve got to change the flavor of that mud, and that can take time.”

Joe Porada, an aquaculturist from Hancock and chairman of the regional shellfish commission there, said it’s important to not introduce shells until all the meat has fallen off, or it serves as an invitation to green crabs. In his area, he’s seen success by using old shells and mess to cover new beds.

The only final, global fix, though, is to roll back carbon, panelists said.

Alternative energy sources, Cousens said, must be embraced. On a recent trip to New Zealand, he saw that nation’s willingness to embrace hydro- and wind-power, and said Maine and the U.S. must do the same.

Green was equally direct.

“We have to limit our carbon emissions,” he said after Cousens spoke. “Democrats want to solve it tomorrow and Republicans don’t want to believe it.”

Paul Anderson of Maine Sea Grant, who moderated the session, said he recently met with staff for Republican members of the U.S. House of Representatives who told him using the words “climate” and “change” in the same sentence was forbidden.

For more information about ocean acidification, see: