Current Conditions of the Northeast Shelf Ecosystem -- Fall 2015 Update
Sea surface temperature (SST) in the Northeast Shelf Large Marine Ecosystem during the first half of 2015 continued to moderate compared to the record high temperatures that occurred in 2012; however, temperatures remain above the long-term mean based on both contemporary satellite remote-sensing data and ship-board measurements.
Spring survey hydrocast data indicate that surface and bottom temperatures were near normal across the northeast U.S. shelf at both the surface and bottom. However, the spatial pattern of SST distribution were suggestive of oceanic influences, perhaps reflecting a shoreward shift in the position of the shelf-slope front – a persistent feature that separates cooler shelf waters from warmer slope waters offshore.
The spring bloom was the largest recorded involving continuous bloom conditions from the Middle Atlantic Bight, to the Georges Bank and Scotian Shelf. The Gulf of Maine spring bloom was of average size and duration.
Spring thermal transition dates for 2015 continue to be among the earliest dates recorded over the past three decades; the spring transition estimate for the Middle Atlantic Bight was the earliest in the time series.
The distribution of fish and invertebrate species sampled by the NEFSC bottom trawl survey has changed; utilizing data through the spring 2015 survey, kernel density plots and the assessments of species distributions both along- and across-shelf show mixed distribution movements over time.