Gone Fishing

Part C: Gone Today, Here Tomorrow?

Georges Bank and surrounding areas with a long history of abundance have seen fish stock depletion and collapse of the fisheries. To speed stock recovery, parts of the area have been closed to fishing as Marine Protected Areas (MPAs) or Closed Areas (CA), shown as blue polygons. Map courtesy of NOAA Fisheries Service.

Stock Assessment

Fishery management's job of stock assessment is difficult in part because fish aren't stationary creatures, like trees, but because they also live underwater. Fishery managers have had to determine best practices to formulate stock assessments and how to develop catch quotas and limits.

1. Read the following excerpt from NOAA's 2018 Report to Congress on the status of US Fisheries to better understand how NOAA tracks U.S. fish stocks.

Fishery management plans must specify objective and measurable criteria (reference points) to determine when a stock is overfished or subject to overfishing. A scientific analysis of the abundance and composition of a fish stock, as well as the degree of fishing intensity, is called a stock assessment. Stock assessments are subject to regional peer review as part of the process to ensure that management decisions are based on the best scientific information available. In fiscal year 2018, NOAA Fisheries conducted 198 stock assessments.

The councils and the agency use information from stock assessments to develop and recommend ACLs and other conservation and management measures. While catch limits are set annually, assessments are often done less frequently. To determine whether catch limits have successfully ended or prevented overfishing, NOAA Fisheries may use the fishing intensity metrics and reference points derived in a stock assessment or a comparison of catch to the overfishing limit (OFL). If the catch-to-OFL comparison is used, an overfishing determination is made annually. If a stock assessment is used, due to timing of the next stock assessment, several years may pass before we are able to determine if catch limits successfully ended overfishing.

Rebuilding Plans for Overfished Stock

Any stock that has previously been listed, or is currently listed, as overfished is required to have a rebuilding program until the stock has been rebuilt to levels consistent with supporting MSY on a sustainable basis. In many locations, such as Georges Bank, this rebuilding plan includes the establishment of Marine Protected Areas.

Beginning in 1994, three large areas totaling 17,000 km2 in Georges Bank were closed to fishing for groundfish. Fishing gear that might catch groundfish incidentally or damage habitats were prohibited, but other forms of fishing such as long-lining were allowed to continue. Additional fishery management measures such as groundfish fishing permit limitation, increase of trawl mesh size, and reduction of groundfish fishing time were also applied. By 1999 there was a 40% reduction in fishing by trawlers, but other forms of gear and fishing for species other than groundfish is still allowed in the areas.

2. Watch this brief video showing scientists taking a trawl assessment and performing other data gathering on the fish and habitat in a closed area on Georges Bank.

Science Bulletins: Will The Fish Return (AMNH)

Scientists did find an increase in groundfish biomass in closed areas. Haddock rebounded well and the stock was considered rebuilt in 2010. However, cod around Georges Bank, and in the whole of the Northwest Atlantic, remained overfished and overfishing continued during a number of years even with the closures in place.


3. The Gulf of Maine Research Institute issued a report in June 2013 titled The Future of Cod in the Gulf of Maine. Read Section 1. Understanding Environmental Change (Acrobat (PDF) 386kB May21 20). (Note: Section 1 begins at the bottom of the first page.)



Checking In

Check your understanding of the report.

  • What are some impacts the warming temperatures may have on cod over their lifetimes?
  • What could declines in body size of Gulf of Maine cod mean?

4. Visit this site to see an animation of annual SST anomalies in the US Northeast from 1982-2017. Note the outlines for the Gulf of Maine and Georges Bank areas. The animation displays temperatures as anomalies, or the degrees warmer or cooler than the long-term SST average. Note that some years are cooler, and some are warmer, and the edge of the continental shelf is clearly delineated in some years of higher SST temperature contrast.

5. Watch this video of a NOAA fisheries oceanographer explaining a 2012 NOAA study of how warming has affected cod.

Changing Ocean Temperatures & Atlantic Cod. If video doesn't play, visit this NOAA website.

6. Read the following 2015 report from Science Collapse of NE's iconic cod tied to climate change

Checking In

Check your understanding of the two reports you just learned about.

  • What could the increase of cooling water in the areas around the northeast shelf be attributed to?
  • How did the distribution of Pseudocalanus link to cod?
  • What happened when the fishery managers didn't know to account for climate change?

 
Although cod and haddock are related species of groundfish, cod continues to be overfished and haddock has rebounded. Recent studies have found that while both species share many of the same needs for cold water habitat, haddock may respond better to slightly warmer temperatures than cod. 

Stop and Think

6: How could knowing the influence of warming waters, such as from climate change, in the Gulf of Maine affect the ways that fisheries managers assess and protect cod stocks? Explain.

 

Optional Extensions

To learn more about the sustainability of Atlantic cod and important dates and events in Atlantic cod management, visit the Atlantic Cod profile at the NOAA Fishwatch website.

GMRI Full Report The Future of Cod in the Gulf of Maine

Research article on the Thermal biology of cod and haddock

Overview of cod and haddock on Georges Bank

WHOI article Why Haven't The Cod Come Back?

Article A Tale of Two Fisheries: Fishing and Overfishing in American Waters

Ocean Circulation in the Northwest Atlantic

Article Cod and the Tragedy of the Commons

The Sorry Story of Georges Bank

Article Warming Waters Exacerbate NE Fisheries

Video Sea Scallops: A Lesson in Sustainability

Video Warming Waters: Seafood Stocks Under Threat in Maine