Further Development Expected of Ecosystem Model

by Laurie Schreiber

MYSTIC, Conn.—The Northeast Fisheries Science Center (NEFSC) is developing a conceptual model to help determine impacts of a changing ecosystem to Georges Bank and the Gulf of Maine.

NEFSC staffer Sean Lucey reported on the latest development to the New England Fishery Management Council (NEFMC) at its April meeting.

The model is expected to help understand how human well-being—including seafood landings and profits, and recreational fishing opporutunities—is affected by changing conditions, according to Lucey’s presentation.

His presentation cited the following points:

• The majority of Gulf of Maine revenue is from a single species—lobster.

• The majority of Georges Bank revenue is from a single species—scallops.

• Forage fish and piscivores are stable or decreasing in landings.

• New England communities have a higher reliance on commercial activities than the Mid-Atlantic.

• Downeast Maine has a stronger reliance than other parts of the region.

• Although recreational opportunities from fishing have increased over the long-term, there’s been a significant decline over the past 10 years, which may have started with the 2008 economic collapse.

• New England has relatively low risk from sea level rise, but moderate to high reliance on species vulnerable to climate.

• Stability studies of commercial fleet and species revenue diversity show long-term declines in the New England, which requires further investigation into mechanisms.

• The North Atlantic right whale may be declining over the most recent few years after a slow but steady increase.

•Temperature is increasing in long-term sea surface records as well as surface and bottom measurements. The seasonal temperature signal also shows sustained warming.

• Shifts in species distribution and changes in productivity have been observed as thermal habitats shift.

• Regional climate indices show a northward movement of the Gulf Stream north wall, which can be a local mechanism for increased temperature and species redistribution.

• Daily variation in sea surface temperature is increasing.

• Deep ocean circulation is weakening, leading to the northward Gulf Stream shift and enhancing sea level rise.

According to a report titled “State of the Ecosystem - Gulf of Maine and Georges Bank” and issued April 6, the overview of ecosystem relationships, as represented by a conceptual model, “helps place more detailed species-level management in context by highighting relationships between focal species groups, managed human activities, environmental drivers, habitats, and key ecological links.”

Lucey said NEFSC is currently working out procedural issues regarding peer review of the model and terms of reference.

“Very provocative report,” said NEFMC member David Pierce, who wanted to know why the report didn’t include a finding that there’s a moderate to high risk of sea level rise. “It seems that’s being minimized.”

But Lucey said the question is addressed in a couple of ways: There could be sea level rise, but the risk to human communities on the northeast shelf is minimal compared with risks in the mid-Atlantic, where there are more low-lying communities that could be more greatly impacted by sea level rise.

Pierce wanted to know if the study addresses the fate of Gulf of Maine lobster in light of ecosystem changes.

“That’s something we’d like to attempt to incorporate, but it’s little tricky,” said Lucey.

Pierce also wanted to know if more study will be made of potential impacts to other species such as gray seals in the Georges Bank area, and squid. Lucey said the further information will be incorporated as it’s obtained.