8.2 Decline of Atlantic Cod.A Case Study
- 1. The Decline of Atlantic Cod – A Case Study by Wynn W. Cudmore, Ph.D. Northwest Center for Sustainable Resources DUE# 0757239 This project supported in part by the National Science Foundation. Opinions expressed are those of the authors and not necessarily those of the Foundation. Bernd Ueberschär – Larval Base project
- 2. Courtesy of the Maritime History Archive (Job Photograph Collection, PF-315.222), Memorial University of Newfoundland, St. John's, NL.
- 3. “The Sacred Cod” House of Representatives of the Massachusetts State House Mark Kasianowicz, Massachusetts State House photographer
- 4. Cod – Basic Biology “Cod - A species too well known to require any description. It is amazingly prolific. Leeuwenhoek counted 9,384,000 eggs in a cod-fish of a midling size - a number that will baffle all the efforts of man to exterminate.” Smith Homans and J. Smith Homans, Jr., editors. 1858. Cyclopedia of Commerce and Commercial Navigation, New York Demersal Broadcast spawners Maximum age 20+ years Omnivorous Sexual maturity 2-4 years NOAA Photo Library
- 5. John Collier / Library of Congress
- 6. The Continental Shelf Georges Bank East Scotian Shelf Grand Banks Northeast Fisheries Science Center NOAA
- 7. Distribution of Atlantic Cod Northeast Fisheries Science Center
- 8. Early History 1497 English explorer John Cabot - “The coast was churning with cod of school size and body size never before seen.” Wikimedia commons NOAA National Marine Fisheries Service
- 9. Cod in the 1500s Newly discovered cod stocks off the coast of Newfoundland were being fished by European fishermen who used single baited hooks “With incredible quantities, and no lesse varietie of kindes of fish in the sea and fresh waters, as Trouts, Salmons and … also Cod, which alone draweth many nations thither, and is becoming the most famous fishing of the world.” 1583 Richard Hayes, a captain for Sir Humphrey Gilbert who claimed Newfoundland for England Profits from Grand Banks cod become a major contributor to European wealth
- 10. 1550 - Cod were so abundant that one English captain reported "that we heardlie have been able to row a boate through them." NOAA National Marine Fisheries Service
- 11. Early harvest methods included handline, longline and gillnets Major U.S. ports (1800s) Gloucester Boston New Bedford NOAA National Marine Fisheries Service Wind-powered schooner Gillnet Fishers retrieve longline from a dory.
- 12. 1880-1910 - First signs of trouble Fishing pressure on the Grand Banks cod stocks increases dramatically due to the decline of inshore stocks Standard of living plummets in Newfoundland 1906 - French steam trawlers appear on the scene © Claude Bélanger, Marianopolis College NOAA National Marine Fisheries Service
- 13. Bottom trawling becomes the harvest method of choice NOAA Photo Library Marine Biology Conservation Institute
- 14. An Early Warning “While the facts before us show no proof or presumption of any depletion of the fisheries on the banks frequented by American otter trawlers, it is possible that the seeds of damage already have been sown and their fruits may appear in the future or that the development of a wholly unregulated fishery eventually may result in injury where none exists.” 1914 Report of the U.S. Commissioner of Fisheries
- 15. Increasing fishing pressure from foreign vessels 1954 - The first factory-freezer trawler, the British fishing vessel Fairtry, fishes the Grand Banks for cod 1968 - over 800,000 tons of cod were harvested accounting for 40% of global fish landings Northeast Fisheries Science Center
- 16. A Soviet factory trawler Northeast Fisheries Science Center
- 17. Atlantic cod landings from Georges Bank 1893 - 2004 Northeast Fisheries Science Center Stock Trends
- 18. Trends in stock sizes of Atlantic cod in the northwest Atlantic 1970-1994 Data from Trippel (1995), Copyright, American Institute of Biological Sciences
- 19. Trends in abundance of spawning Atlantic cod in Canadian waters Data from Hutchings and Reynolds (2004) Copyright, American Institute of Biological Sciences
- 20. Collapse of Atlantic cod stocks off the east coast of Newfoundland in 1992 In 2003, the Newfoundland cod population was declared “endangered” by the Canadian government Millennium Ecosystem Assessment
- 21. "Just 3 years short of the 500-year anniversary of the reports of Cabot's men scooping up cod in baskets, it was over. Fishermen had caught them all.........” Kurlansky 1997
- 22. Distribution and abundance of cod in the Northwest Atlantic 1979-2005 www.nefsc.noaa.gov/read/popdy/cod_animation/
- 23. “If John Cabot were alive today, he would not recognize Georges Bank. Instead of a sea swarming with majestic cod, he would find dogfish. Instead of flounder, he would find skates. Instead of a fisherman’s dream, he would find a nightmare.” U.S. Congressman Gerry Studds 1991
- 24. Population, Community and Ecosystem-level Effects Fishing-induced changes in life history characteristics Fishing-induced evolutionary changes Trophic cascades Habitat alteration
- 25. Fishing-induced changes in life history characteristics Female cod responded to fishing pressure by spawning at an earlier age However, …. … younger females produce smaller and fewer eggs and smaller fry that are more susceptible to predation. Bernd Ueberschär – Larval Base project
- 26. Fishing-induced evolutionary response in Atlantic Cod Fishing pressure exerts strong selection against large individuals in the population …. and, for small, slower growing fish. Woods Hole Oceanographic Institute
- 27. Evidence of a trophic cascade The domino-like effect of removal of a top predator Groundfish biomass Groundfish Landings Seal biomass From: Frank, et al. Science 308, 1622 (2005) reprinted with permission from AAAS
- 28. Habitat Degradation: the impact of fishing gear Dr. R. Grant Gilmore, Dynamac Corporation Lance Horn, National Undersea Research Center/University of North Carolina at Wilmington Before trawling After trawling Deep-sea Oculina coral reefs off Florida's Atlantic Coast
- 30. Damage to benthic habitats may slow the recovery of some fish stocks Before trawling After trawling Fisheries and Oceans Canada
- 31. Cod Management 1953 - Minimum mesh sizes for trawl nets 1975 - International Commission for the Northwest Atlantic Fishery (ICNAF) reduced total allowable catch by half 1976 - U.S. and Canada establish a 200- mile “exclusive economic zone” (EEZ)
- 32. NEFSC
- 33. In the U.S., seasonal and year-round closures were implemented on cod fishing grounds NOAA Fisheries
- 34. The Challenge of Rebuilding Overfished Stocks: Stocks below biomass targets Stocks continue to be “overfished” Slow recovery Low recruitment (the addition of young fish into the population) Cod Recovery Northeast Fisheries Science Center
- 35. Expected recovery after 1993 reduction in fishing effort has not yet occurred From: Frank, et al. Science 308, 1622 (2005) reprinted with permission from AAAS
- 36. Summary of Atlantic Cod History 1500s – Europeans discover Canadian cod stocks 1600s – Cod fishery develops with longlines and single baited hooks 1700s – Newfoundland prosperity is based on cod fishery 1800s – Nearshore stocks decline Early 1900s – Steam trawlers begin fishing for cod 1950s – First appearance of factory-freezer trawlers 1960s – Discovery of additional offshore stocks and increased fishing effort dramatically increase cod harvest 1970s – Canadian TACs reduced and 200-mile limit established 1980s – Canadian and U.S. governments attempt to prop up cod industry with subsidies 1992 – Several cod stocks collapse; fishing moratorium declared 2000s – Cod recovery is limited despite no targeted fishery
- 37. What might be preventing the recovery of Atlantic Cod stocks? directed and non-directed fishing bycatch from other fisheries altered biological systems 1. increased predation (e.g., grey seals, herring) 2. decreased food availability (e.g., capelin, American lobster)
- 38. What might be preventing the recovery of Atlantic Cod stocks? directed and non-directed fishing bycatch from other fisheries altered biological systems fishery-induced changes to life history loss of genetic variability habitat modification by bottom trawling re-opening of closed fisheries the Allee Effect (depensation)
- 39. "Concept" Daniel Pauly; Artist: Aque Atanacio
- 40. What societal factors contributed to the decline of the Atlantic cod? Improved technologies Tragedy of the commons Shifting baselines Government subsidies NOAA Photolibrary
- 41. The Future of Atlantic Cod New England Fishery Management Council’s Northeast Multispecies Fishery Management Plan 2007 - reauthorization of the Magnuson Fisheries Act Proposed Southern Grand Bank marine protected area Can we really implement ecosystem-based fishery management? NOAA Photolibrary
- 42. Summary Atlantic cod has been a cultural and economic resource for centuries Decades of overfishing led to a catastrophic collapse in 1992 Several factors contributed Recovery has been slow despite reduced fishing effort An ecosystem-based approach is required Northeast Fisheries Science Center
- 43. Further reading
- 44. Photo Credits American Institute of Biological Sciences Bernd Ueberschär – Larval Base project Claude Bélanger, Marianopolis College Daniel Pauly Dr. R. Grant Gilmore, Dynamac Corporation Fisheries and Oceans Canada John Collier / Library of Congress Lance Horn, National Undersea Research Center/University of North Carolina at Wilmington
- 45. Photo Credits Marine Biology Conservation Institute Mark Kasianowicz, Massachusetts State House photographer Memorial University of Newfoundland, St. John's, NL. Millennium Ecosystem Assessment NOAA – National Marine Fisheries Service; NOAA Ocean Explorer; NOAA Photo Library; Northeast Fisheries Science Center; Marine Photobank - Sandra Brooke, G. Marola, Robert Stone Science multiple figures, reprinted with permission from AAAS Wikimedia Commons Woods Hole Oceanographic Institute