1. Overfishing and Extinction: Gone Fishing, Fish Gone (1) Fishery: concentration of a particular wild aquatic species suitable for commercial harvesting in a specific area Fishprint: area of ocean needed to sustain the fish consumption of a person, country, or the world Marine and freshwater fish Threatened with extinction by human activities more than any other group of species Bycatch-non target species that are caught up in nets and discarded

3. Overfishing and Extinction: Gone Fishing, Fish Gone (2) Commercial extinction: no longer economically feasible to harvest a species Collapse of the Atlantic cod fishery and its domino effect (put 40,000 people out of work in Newfoundland) Fewer larger fish (lowered trophic levels) More problems with invasive species

4. Natural Capital Degradation: Collapse of the Cod Fishery Off the Canadian Coast Fig. 11-7, p. 257

5. Major Types of commerically harvested marine fish and shellfish Demersal (mostly bottom dwelling): Hake, Haddock, Cod Pelagic (surface dwelling): Sardines, anchovy, herring, mackerel, tuna Crustaceans: Krill, shrimp, lobster, crab Mollusks: Oysters, clam, octopus, squid

6. Case Study: Industrial Fish Harvesting Methods Trawler fishing Purse-seine fishing Longlining Drift-net fishing Bycatch problem

7. 11-3 How Should We Manage and Sustain Marine Fisheries? Concept 11-3 Sustaining marine fisheries will require improved monitoring of fish and shellfish populations, cooperative fisheries management among communities and nations, reduction of fishing subsidies, and careful consumer choices in seafood markets.

8. Estimating and Monitoring Fishery Populations Is the First Step Maximum sustained yield (MSY): traditional approach (difficult can it can change often)-the MOST that can be taken Optimum sustained yield (OSY)-usually set lower than the max sust. Yield to ensure future populations Multispecies management Large marine systems: using large complex computer models Precautionary principle

9. Some Communities Cooperate to Regulate Fish Harvests Community management of the fisheries Co-management of the fisheries with the government Government sets quotas for species and divides the quotas among communities Limits fishing seasons Regulates fishing gear

10. Government Subsidies Can Encourage Overfishing Governments spend 30-34 billion dollars per year subsidizing fishing Often leads to overfishing Discourages long-term sustainability of fish populations

11. Consumer Choices Can Help to Sustain Fisheries and Aquatic Biodiversity Need labels to inform consumers how and where fish was caught 1999: Marine Stewardship Council (MSC) Certifies sustainably produced seafood Proper use of sustainable aquaculture Plant eating fish best -- Tilapia

12. Solutions: Managing Fisheries Fig. 11-11, p. 267

13. Aquaculture Fish farming-involves cultivating fish in a controlled environment, often a coastal or inland pond, lake, reservoir, rice paddy Fish ranching-holding anadromous species (salmon- live part of life in fresh water and part in salt water) in captivity for a few years, releasing them, and then harvesting them as adults when they return to spawn

14. Fish Farm

15. Benefits of Aquaculture High yield in small volume of water Increased yield through crossbreeding and genetic engineering Can reduce overharvesting of wild populations Little use of fuel Profits not tied to price of oil High profits

16. Disadvantages to Aquaculture Large inputs of land, feed, and water needed Large concentration of wastes Destroys coastal ecosystems like mangroves Increased grain production needed to feed some species Fish can be contaminated or killed from pesticide runoff Dense populations vulnerable to disease (which could escape into wild populations) Areas become too contaminated to use after approx. 5 years

17. Legal Protection of Some Endangered and Threatened Marine Species (2) 1975 Convention on International Trade in Endangered Species 1979 Global Treaty on Migratory Species U.S. Marine Mammal Protection Act of 1972 U.S. Endangered Species Act of 1973 U.S. Whale Conservation and Protection Act of 1976 1995 International Convention on Biological Diversity