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Global Ocean Ecosystems Dynamics (GLOBEC) Northwest Atlantic

Issue

bar graph of Northeast Species Groups relative abundance
Northeast Species Groups Relative Abundance

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 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.

Current Projects

Click here for summaries of GLOBEC projects

Accomplishments

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:
NOAA/NOS/NCCOS/CSCOR
Dr. Elizabeth Turner
phone: (301) 713-3338
e-mail: