GloucesterTimes.com, Gloucester, MA

October 8, 2012

Study shows new signs of sea change

By Richard Gaines Staff Writer
Gloucester Daily Times

---- — Sea surface temperatures along the Northeast Shelf Large Marine Ecosystem — the waters off the New England and Mid-Atlantic coasts -- were the highest ever recorded during the first half of 2012, the government reports.

“A profound warming event occurred on the Northeast Shelf this spring, and this will have a profound impact throughout the ecosystem,” said Kevin Friedland, a scientist at NOAA’s Northeast Fisheries Science Center in Woods Hole.

The average sea surface temperature in the region exceeded 51 degrees, surpassing the previous record for the time of year, from 1951. The average sea surface temperature for the time of year over the past three decades was more than three degrees lower than the high

Issued Sept. 18, the report from the science center emphasized that even more extreme variations were documented in two of the ecosystem’s great feeder estuaries -- Cheseapeake and Delaware bays, where temperatures were more than 6 degrees above historical averages on the surface and more than 5 degrees above average at the bottom.

The report was published amid tumultuous changes in the location and concentration of sea creatures of the great Northern Shelf ecosystem — and, by coincidence, five days after the acting Commerce secretary, Roberta Blank, declared the groundfishery of the Northeast from Maine to New York to be an economic disaster, a result of constricting catch limits on stocks determined by NOAA science to be weaker than expected.

Scientists tend to avoid generalizing cause and effect, but there is broad consensus that the warmer waters are pushing many many species -- including cod, the historic bastion of the Northeast commercial fisheries -- off their traditional grounds as they seek optimal new locales for feeding and reproduction.

The advisory posted last month also reported that bottom temperatures were 1 degree warmer in the eastern Gulf of Maine and 2 degrees warmer in the western gulf of Maine.

A 2009 study by the center and referenced in the Sept. 18 release noted that about half the 36 fish stocks studied in the Northwest Atlantic, many commercially valuable, have been shifting northward over the past four decades “with some disappearing from US waters as they move farther offshore.”

An Ecosystem Advisory for the Northeast Shelf ecosystem issued along with the research paper documented in parallel concentration maps how cod distribution is changing (though the advisory stated as a question). But “moderate concentrations of cod in the Nantucket Shoals areas (as shown in the map for 2007-2011) have dissipated (in the 2012 map) and there have been modest increases in abundance along the eastern Maine coast.

“The abundance of fin fish is controlled by a complex set of factors, but with increasing temperature conditions for the ecosystem,” the Science Center noted, “it will be more and more important to monitor the distribution of migratory and non-migratory species.”

“Reports on recent stock abundance declines appear to suggest that the declines are the result of both fishing and an unfavorable environment,” said Brian Rothschild, the distinguished marine scientist at University of Massachusetts-Darmouth. “Yet, management actions seem to assume that fishing is the only cause for stock decline.

“The effect of fishing and the environment are difficult to separate,” Rothschild added in an email to the Times. “Nevertheless, stock assessments can not longer be phrased in the context of fishing alone.

“Assessments need to be phrased in the context of fishing/environmental impacts,:” he added. “Development of such an approach is a major scientific effort that should start now.”

Previous reports by the Science Center have correlated to water temperature the continued weakness in the endangered stock of Atlantic Salmon and projected explosive growth in the stock of Atlantic croaker. The species have conflicting needs, the salmon for colder water while croaker for warmer water.

The disaster declaration was issued nearly 10 months after the request was first filed by Gov. Deval Patrick along with two socio-economic studies showing that the fishing industry of Massachusetts was failing due to reduced catch limits and the catch share management system pushed by NOAA administrator Jane Lubchenco.

Since the filing in November 2011, stock assessments of inshore cod showed a diminished level of restoration and updated assessments of off shore stocks including Georges Bank cod indicated discouraging levels of the stocks.

Richard Gaines can be reached at 978-283-7000, x3464, or at rgaines@gloucestertimes.com.