1. Marine Fisheries: Causes for Decline and Impacts 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.

2. Causes for Marine Fishery Declines Overfishing - The rate of fish mortality (harvest plus bycatch) exceeds the natural rate of replacement. NOAA Photo Library – Teobaldo Dioses

3. Causes for Marine Fishery Declines Overfishing Highly efficient technology - Fishing vessels and gear Radar and sonar Electronic navigation Aircraft with infrared sensors Electronic image intensifiers NOAA Photo Library – C. Ortiz Rojas

4. Bottom trawl Marine Biology Conservation Institute

5. Historical fishing methods NOAA National Marine Fisheries Service

6. Causes for Marine Fishery Declines Overfishing Highly efficient technology Bycatch - The capture of non-target fish or other marine animals in fishing gear NOAA Photo Library

7. Categories of Bycatch Economic discards - species with low or no economic value Regulatory discards – commercially valuable species discarded due to some regulation Collateral mortality - species killed by contact with active or discarded fishing gear

8. Causes for Marine Fishery Declines Overfishing Highly efficient technology Bycatch Overcapacity - Fishing fleets are larger than necessary to harvest the allowable catch NEFSC

9. The Threat of Global Climate Change Potential impacts on physical features of oceans: Sea surface temperatures Sea levels Ocean circulation patterns Salinity pH Potential impacts on marine fish: Migration patterns Changes in reproductive patterns Food web effects

10. The Effect of Changing Ocean Temperatures on Zooplankton Two copepod species in the North Sea: Calanus finmarchicus A cool-water species that has moved north as ocean temperatures increase Populations peak in spring Calanus helgolandicus A warm-water species that has replaced C. finmarchicus Populations peak in fall North Sea Atlantic cod spawn in spring and rely on copepods as a food source Calanus finmarchicus image – NOAA: C.B. Miller/K. Tande

11. The Potential Impact of Rising Sea Levels on Shrimp Production NOAA - Pacific Fisheries Environmental Laboratory Time

12. The Impacts of Recreational Fishing Recreational fishing accounts for 2-3% of total U.S. harvest, but ……. 10% of harvest excluding large industrial fisheries And 23% of harvest of “overfished populations” © John Rafferty Photography/Marine Photobank

13. Recreational harvest as a percent of total U.S. landings for species identified as “overfished” Region% of Landings Gulf of Mexico 64 South Atlantic 38 Pacific Coast 59 Northeast 12 NOAA Historic Fisheries Collection

14. Community and ecosystem-level impacts of fishery declines Fishing down the food web Habitat degradation Trophic cascades Changes in life history traits

15. Artwork © Ray Troll

16. Fishing Down the Food Web The serial harvest of progressively lower trophic levels Time Trophic Level Concept : Daniel Pauly; Artist: Aque Atanacio

17. Fishing Down the Food Web – an illustration from the N. Atlantic Pre-fished Condition 6 trophic levels Current Condition 4 trophic levels Concept : Daniel Pauly; Artist: Aque Atanacio

18. North Pacific Trends in mean trophic levels of marine fisheries landings 1950-1994 Data from Pauly, et al. 1998 Year Mean Trophic Level Global Trends Trends in North Temperate Areas North Pacific Mediterranean Northeast Atlantic Northwest and Central Atlantic

19. Evidence for “fishing down the food web” Millennium Ecosystem Assessment

20. 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 trawlingAfter trawling Deep-sea Oculina coral reefs off Florida's Atlantic Coast

22. Damage to benthic habitats may slow the recovery of some fish stocks Before trawlingAfter trawling Fisheries and Oceans Canada

23. Trophic cascades 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

24. Simplified North Atlantic Food Web Large Predatory Fish Due to fishing pressure Small Pelagic Fish and Benthic Invertebrates (Shrimp + Snow Crab) Grey Seals No longer have large fish as competitors Large herbivorous Zooplankton Phytoplankton

25. Reprinted from Trends in Ecology and Evolution, Vol. 23 Iss. 4, Heithaus, Frid, Wirsing, Worm, Predicting ecological consequences of marine top predator declines (redrawn from Myers, et al. 2007), © 2008 with permission from Elsevier Cownose ray Joe Brown - NOAA A Trophic Cascade from the East Coast

26. Changes in life history traits Female Atlantic cod respond to fishing pressure by spawning at an earlier age Removal of large females reduces reproductive potential NOAA Fisheries

27. Large females produce more offspring Vermillion rockfish Partnership for Interdisciplinary Studies of Coastal Oceans

28. Pew Center on Global Climate Change

29. Why are fishery declines allowed to occur? “Overfishing occurs because all of the economic incentives are in place for it to occur.” Iudicello, et al., 1999 Government subsidies Increasing demand Shifting baselines Lack of adequate fisheries data

30. Government Subsidies to Fisheries Extended unemployment benefits Direct payment Tax exemptions on fuel, fishing gear or vessels Low interest loans or grants Subsidies encourage individuals and businesses to remain in the industry when markets indicate otherwise

31. Increasing Demand for Fish Products Due to increases in both human population and per capita consumption China’s consumption (in millions of tons): 19612003 3.2 25.4 U.S. consumption increased 2.5X over the same time period

32. Shifting Baselines “Fishing has a short memory. If you see twice as many fish as you’ve seen in the last 10 years, it’s still twice as much of not very much.” Teri Frady - NMFS The perception of what is considered “normal” shifts with each generation Post card from Census of Marine Life - History of Marine Animal Populations – Glenn Jones

33. Lack of Adequate Fisheries Data Effective management requires collection and interpretation of basic biological information on fish species and marine ecosystems © Pete Naylor, uwphoto.geckoworks.com 2005 / Marine Photobank

34. Summary Overfishing is the primary cause of marine fishery declines New technologies, bycatch and overcapacity contribute to fishery declines Global climate change poses an emerging threat Fisheries declines have community- and ecosystem-level effects Societal factors such as subsidies, increasing demand, shifting baselines and the lack of fisheries data have allowed fishery declines to occur OAR/National Undersea Research Program (NURP); Alaska Dept. of Fish and Game

35. Photo Credits Census of Marine Life - Glenn Jones Daniel Pauly Fisheries and Oceans Canada Grant Gilmore – Dynamac Corporation Lance Horn – National Undersea Research Center Marine Biology Conservation Institute (MBCI) Marine Photobank – OAR/National Undersea Research Program (NURP); Alaska Dept. of Fish and Game, NOAA Ocean Explorer, Brooke et. al., G.Marola, Pete Naylor, John Rafferty Photography, Robert Stone Millenium Ecosystem Assessment NOAA - Historic Fisheries Collection, National Marine Fisheries Service, Northeast Fisheries Science Center, Pacific Fisheries Environmental Laboratory, S. Brooke, Joe Brown C.B. Miller/K. Tande, NOAA Photo Library – Teobaldo Dioses, C. Ortiz Rojas Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO) Pew Center on Global Climate Change Ray Troll Science multiple figures, reprinted with permission from AAAS Trends in Ecology and Evolution, one figure reprinted with permission from Elsevier