Listed below is background material on the Northeast US Continental Shelf Large Marine Ecosystem. To keep this site up-to-date, users are requested to provide relevant information or links to the LME webmaster.
 

Brief Description:

The Northeast US Continental Shelf Large Marine Ecosystem is characterized by its temperate climate. It extends from the Gulf of Maine to Cape Hatteras along the Atlantic Ocean. Intensive fishing is the primary force driving in the LME, with climate as the secondary driving force. Important hypotheses concerned with the growing impacts of pollution, overexploitation, and environmental changes on sustained biomass yields are under investigation. Efforts to examine changing ecosystem states and the relative health of this LME are underway in four major subareas: the Gulf of Maine, Georges Bank, Southern New England and the estuarine-dominated waters of the Mid-Atlantic Bight. This LME is structurally very complex, with marked temperature and climate changes, winds, river runoff, estuarine exchanges, tides and complex circulation regimes. It is historically a very productive LME of the Northern Hemisphere. LME book chapters and articles pertaining to this LME include Falkowski, 1991, Sissenwine and Cohen, 1991, Sherman, Jaworski and Smayda, 1996, Murawski, 1996, Sherman et al, 2002, and Sherman et al, 2003.

I. Productivity:

This LME is bounded on the east or seaward side by the Gulf Stream. Its complex circulation with meanders and rings greatly influence the LME. The gyre systems of the Gulf of Maine and Georges Bank, and the nutrient enrichment of  estuaries in the southern half of the LME contribute to the maintenance on the shelf of relatively high levels of phytoplankton and zooplankton prey fields for planktivores including fish larvae, menhaden, herring, mackerel, sand lance, butterfish, and marine birds and mammals. For a map of surface circulation, see Sherman et al, 2003, p. 96. For an overview of the physical oceanography of the Shelf, see Brooks, 1996.  The Northeast U.S. Continental Shelf is considered a Category I (>300 gC/m2-yr), highly productive, ecosystem according to SeaWiFS global primary productivity estimates. Since 1977, the NOAA Northeast Fisheries Science Center has monitored this LME for estimates of primary productivity and chlorophyll-a. Productivity varies in the 4 major sub-areas, and from season to season. For a map of estimated annual primary production in this LME, see Sherman et al, 2003, p. 98. For a general summary of the structure, function and productivity of the LME, see Sherman et al, 1996a,b, and c. Zooplankton is used as an indicator of major changes in stability of the lower levels of the food web and of biofeedback responses to oceanographic changes. For zooplankton dynamics in the LME, see Durbin and Durbin, 1996. For a graph and discussion of zooplankton biomass showing peaks and troughs between 1977 to 2001, see Sherman et al, 2003, p. 101-102. While species shifts and interannual and decadal variability have been observed for zooplankton biomass, there appears to be sufficient residual sustainability in biodiversity and abundance to support the recovery of herring and mackerel from their low levels in the mid 1970s. From the systematic monitoring it appears that zooplankton has not undergone any significant decline during the rebuilding of fish stocks (see "Fish and Fisheries"). 

II. Fish and Fisheries:

For population assessments in this LME, see Sherman, Jaworski and Smayda, 1996. For a report on the status of living marine resources in this LME, see NOAA, 1999, and NEFSC Status of the Stocks Report. The catch composition of this LME is quite diverse (see FAO, 2003, figure 5). In the late 1960s and early 1970s, there was intense foreign fishing within the LME. The precipitous decline in biomass of fish stocks was the result of excessive fishing mortality (see Sherman and Busch, 1995). The catch declined from 2.5 million tons in 1990 to 750,000 tons in 1999 (see FAO, 2003, figure 16). The FAO 10-year trend (1990-1999, click on graph to enlarge) shows a marked decrease of gadiformes (cods, hakes and haddocks) catches in the early 1990s leading to the cod collapse of 1993-1994. Significant biomass flips have occurred among dominant species. Dogfish and skates increased in abundance in the 1970s, as groundfish and flounders declined. But a decrease of dogfish and skates has been observed since 1990. For a graph of historic landings of skates and spiny dogfish between 1960 and 1997, see NOAA, 1999, p. 92. For an article on New England groundfish, see NOAA, 1999, p. 71-80. For landings and an abundance index of principal groundfish and flounders from 1960 to 2000, see Sherman et al, 2003. An increase in crustacean catches has been noted in recent years, but it is not clear if this is due to ecological or to economical reasons (see Caddy and Garibaldi, 2000). For the status of Northeast demersal fisheries resources, and for pelagic fisheries (Atlantic mackerel, Atlantic herring, bluefish and butterfish), see NOAA, 1999. The long-term potential yield (a term analogous to the concept of Maximum Sustainable Yield in fisheries science) is set at 1,589,158 tons for this LME (source: NOAA, 1999). The long-term sustainability of high economic yield species depends on the rebuilding of fish stocks through the application of adaptive management strategies. For an article on multispecies fisheries management, see Murawski, 1996. The recovery trend of George’s Bank yellowtail and haddock observed in the late 1990s is linked to reductions in the exploitation rate (see Sherman et al, 2003, p. 107). For information on fishery management plans for this LME, see NOAA, 1999, appendix 2. After 1994, there was an emergency closure of portions of Georges Bank, and severe restrictions on the fishing of haddock. The New England Fishery Management Council (NEFMC) imposed strict restrictions on the fishing of groundfish, and there are efforts to reduce the currently high fishing mortality on lobsters. The Council took measures to reduce fishing effort through reductions of days at sea, a moratorium on new vessel entrants, area closures and an increase in the ring diameter of scallop dredges. For a map of closure areas in this LME, see NOAA, 1999. The closure of half of the U.S. portion of Georges Bank to scallop harvesting to protect groundfish stocks appears to have contributed to an increase in sea scallop stock biomass (see status of fisheries resources off of the Northeastern United States).  Other agencies involved in fisheries management are the Atlantic States Marine Fisheries Commission and the Mid Atlantic Fishery Management Council. Click on New England and Mid-Atlantic Fishery Management Councils to view the efforts of these agencies to control overfishing with management actions.  Several alternative management strategies for the fish stocks of this LME are under consideration by the New England Fisheries Management Council and the Atlantic States Marine Fisheries Commission (see Sherman and Busch, 1995). The Northeast Region has a long history of surveys, but a critical feature of the monitoring strategy is the development of a consistent long term data base for understanding interannual changes and multi year trends in biomass yields (see Sherman and Busch, 1995).  Recent stock assessment reports are also available from NMFS Northeast Fisheries Science Center. The Northeast Fisheries Science Center compiled available information on the distribution, abundance, and habitat requirements for each of the 38 commercially valuable species managed by the New England and Mid-Atlantic Fishery Management Councils.  Although there is not yet a full understanding of fish and fisheries within the context of ecosystem structure and function, advances have been made towards an ecosystem-based strategy for recovering lost biomass. The University of British Columbia Fisheries Center has detailed fish catch statistics for this LME.

III. Pollution and Ecosystem Health:

This LME is under considerable stress from growing near-coastal eutrophication resulting from high levels of phosphate and nitrate discharges into drainage basins (see Sherman and Busch, 1995). Whether the increases in the frequency and extent of nearshore plankton blooms are responsible for the rise in incidence of biotoxin-related shellfish closures (see White and Robertson, 1996) and marine mammals mortalities, remains an important open question. It is of considerable concern to state and federal management agencies (see Sherman et al, 1992a; Smayda, 1991). For this LME as a whole, water clarity is good, dissolved oxygen and coastal wetlands are fair, eutrophic condition, sediment, benthos and fish tissue are poor (see EPA, 2001 for these 7 primary indicators). 60% of estuarine areas have a high potential of increasing eutrophication or existing high concentrations of chlorophyll a. Over 25% of sediments are enriched or exceed the ERL/ERM guidance. Nearly 40% of wetlands along the coast were eliminated between 1780 and 1980. About 10% of fish have elevated levels of contaminants in their edible tissues. Benthic community degradation, fish tissue contamination and eutrophication are increasing. Coastal contamination is especially high along the urbanized and densely populated areas and in poorly flushed waters. Flux levels of zinc, cadmium, copper, lead and nickel are highest in the southern New England region, reflecting the level of urbanization and industrialization. Heavy metal concentrations in demersal fish, crustaceans and bivalve mollusks continue to be monitored as biological indicators (see Schwartz et al, 1996).

IV. Socioeconomic conditions:

The population of the coastal counties of the Northeast coast increased 52% between 1970 and 1990 (U.S. Bureau of the Census, 1996). Major rivers systems (Hudson, Delaware, Chesapeake) contribute nitrates to estuaries and coastal systems due to agriculture, atmospheric deposition and sewage. During the late 1960s and early 1970s, there was intense foreign fishing for mackerel and herring in this LME. Marked alterations in fish abundances were recorded (see Sherman and Busch, 1995).  Analyses of catch per unit effort and fishery independent bottom trawling survey data were critical sources of information used to implicate overfishing as the cause of the shifts in relative abundance among the species of the fish community. Overfishing resulted in reduced landings with excessive effort. Northeast fishermen were adversely affected by the collapse of the groundfish fishery. Effort reductions led to curtailed revenues for fishermen (see NOAA, 1999). A vessel buyout program (1995-1998) provided economic assistance to fishermen adversely affected. This resulted in an approximate 20% reduction in fishing effort (see NOAA, 1999). But local fishermen, especially in the New England area, are at odds with the imposition of fishery management rules which they say jeopardize their ability to earn a living. Pollution reduced the utilization by humans of the marine and coastal resources, but there have been improvements in sewage treatment facilities and the treatment of storm water.

V. Governance:

Governance in this LME is complex, with evidence of progress since 1994. In the 1970s, excessive fishing mortality imposed on the LME’s resources by European factory ships precipitated the passage of US legislation. The 1976 Magnuson Fishing Management Act established a 200-mile Exclusive Economic Zone for the United States that extended jurisdiction over marine fish and fisheries. But the Act’s single species focus neglected predator-prey relationships and other interactions. This focus has often resulted in conflicting goals and bycatch kills (see Murawski, 1996). A joint MAFMC-ASMFC Summer Flounder Fishery Management Plan, initially approved in 1988, has resulted in increased biomass. Regulatory measures since 1994 aimed at a managed recovery of depleted fish stocks through reductions in days at sea, increased minimum mesh sizes, expanded closed areas, and trip limits for depleted cod and haddock stocks. As a result, fishing effort has been reduced. The New England Fishery Management Council’s multispecies fishery management plan sought to eliminate the overfished condition of cod and yellowtail flounder in 5 years, and haddock in 10 years. An amendment in 1996 accelerated the existing days at sea reduction schedule and imposed tighter restrictions through the closure of two fishing areas. It remains difficult to forecast the recovery of cod, haddock and flounders dependent on zooplankton during their planktonic developmental stages. The capacity of the LME to support pelagic and demersal fish still needs study.  Fishing effort must continue to be reduced for the long term sustainability of preferred high demand and high priced species. In terms of pollution and ecosystem health, major programs are being implemented to address the existing problems. For instance, the Chesapeake Bay Program is a partnership with deadline dates to restore the bay (see EPA 2001, p. 84). Wetlands protection regulations have resulted in a decreased loss of wetlands. Coordinated programs with participation from states, academic institutions, the private sector and federal government, are underway to improve monitoring strategies aimed at mitigating the detrimental effects of habitat loss, coastal pollution, eutrophication and overexploitation.

References

Articles and LME volumes:

Anthony, V. C., 1996. The State of Groundfish Resources Off the Northeastern United States. p153-167 In
K.Sherman, N.A. Jaworski, T.J. Smayda. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564pp

Bigford, T. E., 1996. Habitat Mitigation. p. 361-366 In Kenneth Sherman, N.A. Jaworski, T.J. Smayda
(eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564pp.

Brooks, D. A., 1996. Physical Oceanography of the Shelf and Slope Seas from Cape Hatteras to Georges
Bank: A Brief Overview. p.47-74 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564pp

Capuzzo, J.E.M., 1996. Biological Effects of Cotaminants on Shellfish Populations in Coastal Habitats: A
Case History of New Bedford, Massachusetts, p.457-466 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management, Blackwell Science, Cambridge, MA , 564pp.

Durban, E. G. and A. G. Durbin. 1996. Zooplankton Dynamics in the Northeast Shelf Ecosystem, p.129-
152 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management, Blackwell Science, Cambridge, MA. 564pp.

EPA, 2001. National Coastal Condition Report.

Epstein, P. R. 1996. Emergent Stressors and Public Health Implications in Large marine Ecosystems: An
Overview, p.417-438 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564pp.

Falkowski, 1991. A carbon budget for the northeast continental shelf ecosystem: results of the shelf edge
exchange process studies. In K Sherman, L.M. Alexander and B.D Gold, “Food chains, yields, models, and management of large marine ecosystems”.

FAO, 2003. Trends in oceanic captures and clustering of large marine ecosystems—2 studies based on the FAO capture database. FAO fisheries technical paper 435. 71 pages.

Ingham, M. C. 1996. Effects of Closure of a Continental Shelf Dump Site, p.441-456 In K. Sherman, N.A.
Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA., 564pp.

Jaworski, N. A. and R. Howarth. 1996. Preliminary Estimates of the Pollutant Loads and Fluxes into the
Northeast Shelf Ecosystem, p.351-357 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564pp.

Juda, L. 1996. "Developing International Law and Ecosystem-Based Fisheries Management," in Kenneth
Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.527-533.

Kenney, R.D., P.M. Payne, D.W. Heinemann and H.E. Winn. 1996. "Shifts in Northeast Shelf Cetacean
Distributions Relative to Trends in Gulf of Maine/Georges Bank Finfish Abundance," in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.169-196.

Malone, T. C. and D. J. Conley. 1996. Trends in Nutrient Loading and Eutrophication: A Comparison of
the Chesapeake Bay and the Hudson River Estuarine Systems, in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.327-349.

Murawski, S. A. 1996. "Can we Manage Our Multispecies Fisheries?," in Kenneth Sherman, et al. (eds.),
The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.491-510.

NOAA, 1999. Our living oceans—report on the status of U.S. Living Marine Resources. 301 pages.

O’Connor, T. P. 1996. "Coastal Sediment Contamination in the Northeast Shelf Large Marine Ecosystem,"
in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.239-257.

Peters, D. S. and F. A. Cross. 1996. "Relating Habitat Stress to Fish Productivity: Problems and
Approaches," in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.397-404.

Schneider, D. and D. W. Heinemann. 1996. "The State of Marine Bird Populations from Cape Hatteras to
the Gulf of Maine," in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.197-216.

Schwartz, J. P., N.M. Duston, and C.A. Batdorf. 1996. Metal Concentrations in Winter Flounder, American
Lobster, and Bivalve Molluscs from Boston harbor, Salem Harbor, and Coastal Massachusetts: A Summary of Data on Tissues Collected from 1986 to 1991, p.285-312 In Kenneth Sherman, N.A.Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA , 564pp.

Sherman, K, Grosslein, M, Mountain, D, O’Reilly, J and R. Theroux, 1988. The continental shelf
ecosystem off the northeast coast of the United States. In: Postma, H.; Zijlstra, J.J., eds. Ecosystems of the world 27: continental shelves. Amsterdam, The Netherlands: Elsevier; p. 279-337.

Sherman, K. and DA Busch, 1995. Assessment and monitoring of large marine ecosystems. In: Rapport D.J,
Guadet, C.L. and Calow, P. (Eds.) Evaluating and monitoring the health of large-scale ecosystems. Springer-Verlag, Berlin. (Published in cooperation with NATO Scientific Affairs Division). NATO Advanced Science Institutes Series. Series 1: Global Environmental Change, Vol. 28. pp. 385-430.

Sherman, K., N.A. Jaworski, T.J. Smayda, 1996. The Northeast Shelf Ecosystem—Assessment,
Sustainability, and Management. Blackwell Science. 564 pages.

Sherman, K. et al. 1996a. "The Northeast Shelf Ecosystem: An Initial Perspective," in Sherman,
Jaworski and Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and
Management (Cambridge, MA: Blackwell Science, 1996) pp. 103-126.

Sherman, K. et al. 1996b. "Zooplankton Prey Field Variability During Collapse and Recovery of Pelagic
Fish in the Northeast Shelf Ecosystem," in Sherman, Jaworski and Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.217-236.

Sherman, K. et al. 1996c. "Summary and Recommendations for the Mitigation of Stress," in Kenneth
Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.535-537.

Sherman, K., J. Kane, S. Murawski, W. Overholtz and A. Solow. 2002. The U.S. Northeast Shelf Large
Marine Ecosystem: Zooplankton trends in Fish Biomass Recovery. p.195-215 In K. Sherman and H.R. Skjoldal, (eds.). Large Marine Ecosystems of the North Atlantic—Changing states and Sustainability. Volume in press, Elsevier Science B.V., New York. 449pp.

Sherman, K., J. O’Reilly and J. Kane, 2003. “Assessment and sustainability of the US Northeast Shelf
Ecosystem. In: K. Sherman and G. Hempel, Large Marine Ecosystems of the World – Trends in Exploitation, Protection and Research.

Sissenwine, M. and E. Cohen, 1991. Resource productivity and fisheries management of the Northeast
Shelf Ecosystem. In: K. Sherman, LM Alexander and BD Gold (eds), “Food Chains, Yields, Models, and Management of Large Marine Ecosystems”. Westview Press, Boulder.

Smith, T. et al. 1996. "Multispecies Approaches to Management of Large Marine Predators," in Kenneth
Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.467-490.

Thomas, J. P. 1996. "Status, Trends, and Health of Wetlands: A 200-Year Overview," in Kenneth Sherman,
et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.367-396.

White, H. H. and A. Robertson. 1996. "Biological Responses to Toxic Contaminants in the Northeast Shelf
Large Marine Ecosystem," in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.259-283.

Windom, H. L. 1996. "Riverine Contributions to Heavy Metal Inputs to the Northeast Shelf Ecosystem," in
Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.313-325.

Other references:

Anderson, E.D., R.K. Mayo, K. Sosebee, M. Terceiro, and S.E. Wigley. 1999. Northeast Demersal
Fisheries. p. 89-97 In Our Living Oceans: Report on the Status of U.S. Living Marine Resources, 1999. U.S. Dep't. of Commerce, NOAA Tech. Mem. NMFS-F/SPE-41, 301pp

Anderson, E.D., K.D. Friedland, and W.J. Overholtz. 1999. Northeast Pelagic Fisheries. p. 99-102 In Our
Living Oceans: Report on the Status of U.S. Living Marine Resources, 1999. U.S. Dep't. of Commerce, NOAA Tech. Mem. NMFS-F/SPE-41, 301pp.

Anderson, E.D., S.X. Cadrin, L.C. Hendrickson, J.S. Idoine, H.-L. Lai, and J.R. Weinberg. 1999. Northeast
Invertebrate Fisheries. p. 109-115 In Our Living Oceans: Report on the Status of U.S. Living Marine Resources, 1999. U.S. Dep't. of Commerce, NOAA Tech. Mem. NMFS-F/SPO-41, 301pp.

Behrenfeld, M.J. and P.G. Falkowski. 1997. Photosynthetic Rates Derived from Satellite-based Chlorophyll
Concentration. Limnol. Oceanogr., 42(1)1-20.

Caddy, JF and L Garibaldi, 2000. Apparent changes in the trophic composition of world marine harvests:
the perspective from the FAO capture database. Ocean and Coastal Management. 43 (8-9): 615-655.

Heinz, H. John III Center for Science, Economics and the Environment. 2000. Fishing Grounds: Defining a
New Era for American Fisheries Management. Island Press. Washington, DC. 241 pp.

O'Reilly, J.E., M. Behrenfeld, J. Yoder, and G. Wood. 1999. Primary Production in the Northeast US Shelf
Ecosystem Using the VGPM and High-Resolution Satellite Ocean Color Data from CZCS and SeaWiFS. EOS, Trans. Amer. Geophys. Union. 80(49)154.

O'Reilly, J.E. and C. Zetlin. 1998. Seasonal, Horizontal, and Vertical Distribution of Phytoplankton
Chlorophyll a in the Northeast U.S. Continental Shelf Ecosystem. U.S. Dep't. of Commerce. NOAA Tech. Rep. NMFS 139, 120pp.

O'Reilly, J.E., C. Evans-Zetlin, and D.A. Busch. 1987. Primary Production. p. 220-233 In: R. Backus (ed.).
Georges Bank, MIT Press, Cambridge, MA. 593pp.

modified 28 October 2003