'Record Ocean Temperatures Recorded Off New England Coast
Published: Sunday 23 September 2012
“The warm waters led to the earliest,
most intense and longest-lasting plankton bloom on record,
with implications for marine life, from the smallest creatures to the
largest marine mammals like whales.”
Federal
ocean scientists said this year’s sea surface temperatures along the
northeast coast of the U.S. set all-time records, with as-yet unknown
consequences for marine ecosystems.
In deeper offshore waters to the north, bottom waters were 2
degrees warmer in the eastern Gulf of Maine and more than 3.6 degrees
warmer in the western Gulf of Maine.
Above-average temperatures were found in all parts of the
ecosystem, from the ocean bottom to the sea surface and across the
region, and the above average temperatures extended beyond the shelf
break front to the Gulf Stream, according to an ecosystem advisory
issued by NOAA’s Northeast Fisheries Science Center.
The warm waters led to the earliest, most intense and
longest-lasting plankton bloom on record, with implications for marine
life, from the smallest creatures to the largest marine mammals like
whales. Atlantic cod continued to shift northeastward from its historic
distribution center.
“A pronounced warming event occurred on the Northeast
Shelf this spring, and this will have a profound impact throughout the
ecosystem,” said Kevin Friedland, a scientist in the NEFSC’s Ecosystem
Assessment Program. “Changes in ocean temperatures and the timing of the
spring plankton bloom could affect the biological clocks of many marine
species, which spawn at specific times of the year based on
environmental cues like water temperature.”
Friedland said the average sea surface temperature
exceeded 51 degrees during the first half of 2012, topping the previous
record high set in 1951.The average sea surface temperature the past
three decades has ranged around 48 degrees.
Temperatures climbed even higher than that in some
near-shore locations like Delaware Bay and Chesapeake Bay, where sea
surface temperature readings were more than 6 degrees above historical
average and more than 5 degrees above average at the seafloor.
This year’s record-high ocean temperatures are a spike in a
long-term trend that is push many commercial fish farther north and
east in a response to ecosystem warming.
A 2009 study of
data from 1968 to 2007 found that about half of the 36 fish stocks
studied in the Northwest Atlantic Ocean have been shifting northward
over the past four decades, with some disappearing from US waters as
they move farther offshore.
Friedland said that, although cod didn’t shift as much as
other species like hake in the 2009 study, the effects of warming water
on ocean currents and other ocean circulation patterns could change
that.
“Cod distribution continues to be dynamic, with northerly
shifts detected in the spring 2012 data, consistent with a response to
ecosystem warming,” Friedland said. “The big question is whether or not
these changes will continue, or are they a short-term anomaly?”
Mike Fogarty, who heads the Ecosystem Assessment Program,
says the abundance of cod and other finfish is controlled by a complex
set of factors, and that increasing temperatures in the ecosystem make
it essential to monitor the distribution of many species, some of them
migratory and others not.
“A complex combination of factors influence ocean
conditions, and it isn’t always easy to understand the big picture when
you are looking at one specific part of it at one specific point in
time, “Fogarty said. “We now have information from a variety of sources
collected over a long period of time on the ecosystem, and are
continually adding more data to clarify specific details. The data
clearly show a relationship between all of these factors.”
The 2012 spring plankton bloom, one of the longest
duration and most intense in recent history, started at the earliest
date recorded since the ocean color remote sensing data series began in
1998. In some locations, the spring bloom began in February, and was
fully developed by March in all areas except Georges Bank, which had an
average although variable spring bloom. The 2012 spring bloom in the
Gulf of Maine began in early March, the earliest recorded bloom in that
area.
“What this early start means for the Northeast Shelf
ecosystem and its marine life is unknown,” Fogarty said. “What is known
is that things are changing, and we need to continue monitoring and
adapting to these changes.”
Plankton samples are collected six times a year in each of
the four subareas of the Northeast Shelf: the Middle Atlantic Bight,
Southern New England, Georges Bank, and the Gulf of Maine. EcoMon
scientists also collect water samples and other oceanographic data about
conditions during each season in each of the four areas to provide a
long-term view of changing conditions on the Shelf.
Ecosystem advisories
have been issued twice a year by the NEFSC’s Ecosystems Assessment
Program since 2006 as a way to routinely summarize overall conditions in
the region. The reports show the effects of changing coastal and ocean
temperatures on fisheries from Cape Hatteras to the Canadian border. The
advisories provide a snapshot of the ecosystem for the fishery
management councils and also a broad range of stakeholders from
fishermen to researchers.
The Spring 2012 Ecosystem Advisory with supporting information is available online. To access, click here.'
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