Northeast Species Groups Relative Abundance
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.
The U.S. Global Ocean Ecosystems Dynamics (GLOBEC) Program is a large
multi-disciplinary, multi-year oceanographic effort jointly sponsored
by NCCOS' Center for Sponsored Coastal Ocean Research (CSCOR) and the
National Science Foundation (NSF). NOAA/NMFS has provided scientific
and research vessel support. 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 through June of every year from 1995-2000. Moorings
were in place continuously during this time, 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 ongoing modeling efforts which seek
to provide realistic predictions of the flow field and 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 project built upon and complemented the CSCOR-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 and Policy Implications
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 NOAA Fisheries 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.
Click here for summaries of GLOBEC projects
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.
For more information, contact:
Dr. Elizabeth Turner
phone: (301) 713-3338