U.S. Global Ocean Ecosystem Dynamics
(GLOBEC)
Northwest Atlantic
ISSUE
The collapse of the northwest
Atlantic groundfish fisheries has focused the attention of both management
and science on critical gaps in knowledge. Spawning stock biomass of cod has
become so sufficiently low that some fishery areas were closed in 1993, and
in 1995 the closure area was expanded. Issues that must be addressed to resolve
this problem include: the criteria to define and open a species/area management
unit to fishing; the management strategy needed for a multi-species ecosystem
approach; the effect of trawling activity on the benthic food supply of commercially
important species; and setting practical management objectives given the degree
of environmental variability in the North Atlantic.
APPROACH
The U.S. Global Ocean Ecosystems
Dynamics (GLOBEC) Program is a large multi-disciplinary, multi-year oceanographic
effort jointly sponsored by NOAA's COP and the National
Science Foundation (NSF). NOAA/NMFS
has provided scientific and research vessel support, and scientists participate
from Federal, academic, and private institutions across the nation. One of
the study areas for U.S. GLOBEC is Georges Bank in the Gulf of Maine. The
proximate goal of the GLOBEC
Georges Bank program is to understand the population dynamics of key species
on the Bank - cod, haddock, and two species of zooplankton (Calanus finmarchicus
and Pseudocalanus) - both in terms of their coupling to the physical
environment and their predator/prey relationships. The ultimate goal is to
be able to predict changes in the distribution and abundance of these species
as a result of changes in their physical and biotic environment as well as
to anticipate how their populations might respond to climate variability and
change.
The effort is substantial, requiring information on many scales. Broad-scale
cruises have described physical and biological conditions on the bank during
January-June every year since 1995. Moorings have been in place continuously
recording information over a long time series. Process studies, described
in more detail below, focused both on the links between the target species
and their physical environment, and the determination of fundamental aspects
of key species' life history (birth rates, growth rates, death rates, etc).
Equally important are the modeling efforts that are ongoing which seek to
provide realistic predictions of the flow field and which utilize the life
history information to produce an integrated view of the dynamics of the populations.
Retrospective analysis has provided information over a longer time frame,
and has helped to place the current study in historical context.
The GLOBEC Georges Bank program has had three years of extensive field process
study (1995, 1997, and 1999). Phase 1 (1994-1996) focused on stratification
of the water column, and its effects on circulation around Georges Bank. Phase
2 (1996-1999) examined the sources, retention and loss processes affecting
zooplankton populations on Georges Bank. Phase 3 (1999-2000) determined cross-frontal
exchange process and how they influenced populations moving onto and off of
the bank. Over one hundred cruises
took place during the field work of the program, with scientists spending
1174 days at sea. The final phase of GLOBEC Georges Bank is focusing on analysis
and synthesis of the field results, with special attention to physical/biological
modeling, climate effects, and development of indices to characterize environmental
and ecosystem status and change.
The GLOBEC project builds upon
and complements the COP-funded "Predation and Structure of the Georges Bank
Ecosystem," which focused on multi-species predation on the early life stages
of cod and haddock.
MANAGEMENT ORIENTED RESULTS
Key indices will be developed
to monitor changes to the ecosystem. Models will provide new, ecosystem-based
estimates of abundances and distributions for improved fishery forecasts.
Research results will be provided routinely to the NMFS
Northeast Fisheries Science Center and to the New
England Regional Fishery Management Council. Results have already been
provided to the New England Fishery Management Council in their deliberations
on the reopening of closed areas on Georges Bank to scalloping.
Related Websites
For more information, contact:
Elizabeth Turner
CSCOR/Coastal Ocean
Program
phone: 301-713-3338
e-mail: coastalocean@noaa.gov
Last Updated:
October 23, 2002
