Atlantic Cod (Gadus morhua)

• Atlantic cod populations are low, and strict rebuilding measures have been implemented.
• Recent studies link the effects of climate change to decreases in cod populations in the North Atlantic.
• Cod is a good source of low-fat protein, phosphorus, niacin, and vitamin B12. For more on nutrition, see Nutrition Facts. (USDA)
• Only about 2% of the U.S. cod sold in 2005 were Atlantic cod; the rest were Pacific cod, a very healthy population. About 17% of the cod bought in the U.S. in 2005 was imported.

Sustainability Status

Biomass: The biomass of both Georges Bank and Gulf of Maine stocks is well below the biomass needed to support maximum sustainable yield, at 10% and 23% of the target biomass, respectively.
Overfishing: Yes
Overfished: Yes
Fishing and habitat: Otter trawls, gillnets, and longlines are used in the Atlantic cod fishery. Gillnets and longlines have very little or no impact on habitat. Otter trawls may impact habitat, depending on where they are used. For more information, see Fisheries Gear.
Bycatch: The Northeast Region Bycatch Priorities and Implementation Plan identified harbor porpoise and large cetaceans (whales, dolphins, and porpoise) as bycatch of concern in the New England gill net fishery. The Northeast Multispecies FMP, Harbor Porpoise Take Reduction Plan, Large Whale Take Reduction Plan, and the Marine Mammal Protection Act include several direct and indirect measures aimed at reducing bycatch in this fishery.
Aquaculture: Part of NOAA's 10-year Aquaculture Plan is to determine whether marine fish like cod are suitable candidates for aquaculture. NOAA research is being conducted on aquaculture of haddock and cod. Atlantic cod culture is a primary focus of Scandinavian aquaculture researchers. Ongoing work in Norway and elsewhere could also contribute to U.S. efforts to domesticate cod.

Science and Management

In U.S. waters, Atlantic cod are assessed and managed as two stocks: 1) Gulf of Maine and 2) Georges Bank and Southward. These stocks are managed under the New England Fishery Management Council's Northeast Multispecies Fishery Management Plan (FMP). Several other species share the same habitat as cod and are therefore managed concurrently. This FMP has implemented closures, gear restrictions, minimum size limits, and other management measures to reduce fishing mortality to levels that will allow stocks to rebuild above minimum biomass thresholds and, ultimately, remain at or near the target biomass levels. Currently, biomass of both stocks remains at an extremely low level. The Georges Bank stock is under a 22-year rebuilding plan, and the Gulf of Maine stock is under a 10-year plan.

The Georges Bank cod stock is also a transboundary resource, meaning the stock migrates across international boundaries. Therefore, management of a portion of this stock is coordinated with Canada. The Canadian fishery on Georges Bank is managed under an individual quota system. An informal quota-sharing understanding between Canada and the U.S. was implemented in 2004 to share the harvest of cod in the transboundary portion of the stock. This understanding includes total allowable catch quotas for each country as well as in-season monitoring of the U.S. catch of cod on eastern Georges Bank.

Recent research has indicated a relationship between climate change and the decline of bottom species like cod. In an ICES Journal of Marine Science article called "The response of Atlantic cod (Gadus morhua) to future climate change", researcher Kenneth Drinkwater links expected increases in ocean temperature to the decline of Georges Bank cod stocks, based on observed responses of cod to temperature variability. However, the responses of cod to future climate change are highly uncertain as they depend on changes to other variables besides temperature, like plankton production, prey and predators, and industrial fishing.

Life History and Habitat

Life history, including information on the habitat, growth, feeding, and reproduction of a species, is important because it affects how a fishery is managed. High reproductive potential in Atlantic cod means they should respond quickly to the increasingly strict management measures; however, the abundance of cod (biomass) continues to be low. One scientific study suggested that issues like fishing on coastal spawning groups, pollution of important coastal habitats, and reductions in potential food sources through construction of dams may help explain why biomass remains low. Also, the impacts of bottom habitat disturbance and destruction may impact the ability of juvenile cod to survive and recruit to the fishery. The true impact of regulatory discards (dead fish returned to the sea) may have a larger effect on rebuilding than currently understood.

• Geographic range: In the Atlantic Ocean from Greenland to North Carolina
• Habitat: Adults are demersal, or live close to the bottom, in depths of 32.8 to 492 feet.
• Life span: Over 20 years
• Food: A variety of invertebrate and fish species
• Growth rate: Growth of cod is dependent on temperature. Growth rates are slower in Gulf of Maine than Georges Bank.
• Maximum size: Can grow up to lengths of 51 inches and weights up to 55-77 pounds.
• Reaches reproductive maturity: At 2 to 3 years, or between 12.6 and 16 inches
• Reproduction: Cod have high reproductive potential, or fecundity. Large females can produce between 3 and 9 million eggs.
• Spawning season: Winter through early spring
• Spawning grounds: Near the bottom
• Migrations: In the middle of their geographic range, cod move somewhat in response to changing water temperatures. The northern and southern parts of the population have more extensive migrations than the middle.
• Predators: Many fish prey on larval and juvenile cod, but adults are so large that they have few predators, typically just sharks.
• Commercial or recreational interest: Both
• Distinguishing characteristics: Adults are heavy-bodied and have a large head, a blunt snout, and a distinct barbel (a whisker-like organ, like on catfish) under the lower jaw. Their coloring varies, but they usually have many small spots and a pale lateral line.

Role in the Ecosystem

Cod are top predators in the benthic (bottom) ocean community. However, as an article published in Science magazine describes, commercial exploitation of cod and other bottom fish have led to changes in the food web. With cod and other predatory groundfish populations currently at low levels, populations of bottom-living species preyed upon by cod, such as small pelagic fishes and invertebrates like northern snow crab and northern shrimp, have increased. This increase has led to changes in numbers of phytoplankton (tiny floating plants) and zooplankton (tiny animals like copepods) that support these communities.

Additional Information

Market name: Cod
Vernacular names: Codling, Scrod cod (a term for small fresh cod; other sizes are "markets" and "steakers")
Other species are also marketed as cod.

Biomass

Biomass refers to the amount of Atlantic cod in the ocean. Scientists cannot collect and weigh every single fish to determine biomass, so they use models to estimate it instead. These biomass estimates can help determine if a stock is being fished too heavily or if it may be able to tolerate more fishing pressure. Managers can then make appropriate changes in the regulations of the fishery. Atlantic cod biomass is presented as spawning stock biomass, or the amount of Atlantic cod in the population at reproductive maturity. Currently, both the Georges Bank and Gulf of Maine stock are rebuilding spawning stock biomass to target levels.

Landings

Landings refer to the amount of catch that is brought to land. Stricter management measures were enacted throughout the 1990s, contributing to the decline in domestic commercial landings in the past 15 years.

Note: The landings presented are domestic commercial landings.

Biomass and Landings

Are landings and biomass related? Landings are dependent on available biomass, management measures in the fishery, and fishing effort.

Data sources:
Biomass and landings from NOAA Northeast Fisheries Science Center Assessment of the Georges Bank Atlantic Cod Stock for 2005 and 2005 Assessment of the Gulf of Maine Atlantic Cod Stock

Important Dates

1953-1977 – The International Commission for the Northwest Atlantic Fisheries, now the Northwest Atlantic Fisheries Organization, takes lead on research and management of fisheries in the Northwest Atlantic, including Atlantic cod. Member countries include the United States, Canada, the United Kingdom, and Iceland.
1960s – International fishing efforts add pressure to existing domestic fleet
1976 – United States takes control of its Exclusive Economic Zone (3-200 miles offshore) by eliminating foreign fishing in these waters
1977 – Fishery Management Plan for Atlantic Groundfish sets minimum mesh sizes of nets, determined quotas for cod catch, and closed areas to cod fishing 
1984 – The "Hague" line establishes separate fishing zones for the United States and Canada in the Gulf of Maine and Georges Bank
1986 – Northeast Multi-Species Fishery Management Plan (FMP) includes management of cod and 14 other fish species, setting minimum size for net mesh and retainable fish and implementing seasonal closures
1994 – Amendment 5 to the Multi-Species FMP caps participation in the fishery and establishes additional measures to reduce fishing effort in the Atlantic cod fishery
1995 – Pilot program initiated to "buyout" vessels (buying vessels and removing them from the fishery)
1996 – Amendment 7 further controls days spent at sea and the amount of cod harvested
1999 – Amendment 9 establishes biomass rebuilding targets and defines control rules specifying target fishing mortality rates and corresponding rebuilding timeframes
2002 – 245 multi-species permits removed from the multi-species fishery, reducing pressure on cod populations
2004 – Amendment 13 implemented to end overfishing on all groundfish stocks and to rebuild all groundfish stocks that are overfished
2006 – Measures are implemented to further reduce mortality

Notes and Links

General Information:
NMFS Sustainability Species Identification for Atlantic cod

NOAA Technical Memorandum NMFS-NE-190 Essential Fish Habitat Source Document: Atlantic Cod, Gadus morhua, Life History and Habitat Characteristics, Second Edition (2004)

NOAA Technical Memorandum NMFS-NE-181: Characterization of the Fishing Practices and Marine Benthic Ecosystems of the Northeast U.S. Shelf, and an Evaluation of the Potential Effects of Fishing on Essential Fish Habitat (2004)

NMFS Northeast Regional Office Current Bycatch priorities and Implementation Plan (2005)

NOAA Aquaculture Program Interim Final 10-Year Plan for the NOAA Aquaculture Program (2006)

NMFS Report to Congress on Northeast Multi-species harvest capacity and impact of northeast fishing capacity reduction (2002)

New England Fishery Management Council

Fishery Management:
New England Fishery Management Council Northeast Multispecies Fishery Management Plan

New England Fishery Management Council Northeast Multispecies Fishery Management Amendments, Frameworks, and other information

Stock Assessments:
NOAA Northeast Fisheries Science Center Assessment of the Georges Bank Atlantic Cod Stock for 2005

NOAA Northeast Fisheries Science Center 2005 Assessment of the Gulf of Maine Atlantic Cod Stock