"Many factors are involved in these shifts, including temperature, population size, and the distributions of both prey and predators," said Jon Hare, a scientist in the NEFSC's Oceanography Branch. A number of recent studies have documented changing distributions of fish and shellfish, further supporting NEFSC work reported in 2009 that found about half of the 36 fish stocks studied in the Northwest Atlantic Ocean, many of them commercially valuable species, have been shifting northward over the past four decades.
The Northeast U.S. Continental Shelf Large Marine Ecosystem (LME) extends from the Gulf of Maine to Cape Hatteras, North Carolina. The NEFSC has monitored this ecosystem with comprehensive sampling programs since1977. Prior to 1977, this ecosystem was monitored by the NEFSC through a series of separate, coordinated programs dating back decades.
Warming conditions on the Northeast Shelf in the spring of 2012 continued into September, with the most consistent warming conditions seen in the Gulf of Maine and on Georges Bank. Temperatures cooled by October and were below average in the Middle Atlantic Bight in November, perhaps due to Superstorm Sandy, but had returned to above average conditions by December.
"Changes in ocean temperatures and the timing and strength of spring and fall plankton blooms could affect the biological clocks of many marine species, which spawn at specific times of the year based on environmental cues like water temperature," Kevin Friedland, a scientist in the NEFSC Ecosystem Assessment Program, said. He noted that the contrast between years with, and without, a fall bloom is emerging as an important driver of the shelf's ecology. "The size of the spring plankton bloom was so large that the annual chlorophyll concentration remained high in 2012 despite low
|Contact: Shelley Dawicki|
NOAA Fisheries Northeast Fisheries Science Center