Marine Biodiversity Threats and Conservation Unless otherwise noted, pictures and diagrams are ©Brooks/Cole 2007

Over-fishing: About 75% of the world’s commercially valuable marine fish species are over fished or fished near their sustainable limits. Big fish are becoming scarce. Smaller fish are next. 30% of the fish that are caught are discarded. Bycatch: sea mammals, sea birds, and sea turtles

Tragedy of the Commons Some resources are widely available and owned by no one (or everyone, depending on your perspective). Many fisheries stand by the concept “if I don’t take it, someone else will”. (A) Trajectories of collapsed fish and invertebrate taxa over the past 50 years (diamonds, collapses by year; triangles, cumulative collapses). Data are shown for all (black), species-poor (<500 species, blue), and species-rich (>500 species, red) LMEs. Regression lines are best-fit power models corrected for temporal autocorrelation. (Worm et al 2006, Figure 3A)

Commercial and Recreational Fishing Figure 1. Frequency distributions of maximum known declines among marine fish populations over periods of at least 10 years, shown (a) for all 232 populations (the median decline of 83% is identified by a vertical line) and for 3 families: (b) Clupeidae (n = 56, median decline = 91%; includes Atlantic herring, Clupea harengus); (c) Gadidae (n = 70, median decline = 80%; includes Atlantic cod, Gadus morhua, and haddock,Melanogrammus aeglefinus); and (d) Pleuronectidae (n = 30, median decline = 74%; includes flatfishes such as flounder, sole, and halibut). Hutchings and Reynolds 2004

Commercial and Recreational Fishing Start here with C block Thursday

Deep sea aquaculture cage Fish caught by gills Trawler fishing Fish farming in cage Spotter airplane Sonar Purse-seine fishing Trawl flap Trawl lines Fish school Trawl bag Drift-net fishing Long line fishing Float Buoy Figure 12.A Natural capital degradation: major commercial fishing methods used to harvest various marine species. These methods have become so effective that many fish species have become commercially extinct. Lines with hooks Deep sea aquaculture cage Fish caught by gills Fig. 12-A, p. 255

Magnuson-Stevens Fishery Conservation and Management Act 1976 Created 8 regional fisheries management councils: NE, Mid-Atlantic, S Atl, Gulf of Mexico, Caribbean, N. Pac, Pac, W. Pac Councils are made up of fishermen, industry representatives, and fisheries scientists Councils create Fisheries Management Plans Fisheries Management Plans ID species that need managing Analyze biological, economic, environmental, and social factors at play Prepare a plan to sustain the resource while still allowing for exploitation (Maximum Sustainable Yield, MSY)

More on Magnuson-Stevens Amended in 1996 to include provisions for protecting Essential Fish Habitat Federal agencies must now consider EFH when reviewing permit or license requests and when formulating their FMPs Reality: trawling damages EFH but is still the most common means of commercial fishing Start here with A block Wednesday

Result of EFH: Gulf of Maine Example © NERONMFS

Commercial whaling: another tragedy of the commons 1925-1975 1.5 million whales killed Commercial exploitation became more efficient with spotter planes, fast ships, mechanized harpoon guns, and inflation lances 8 of 11 major species reduced to levels not profitable to hunt any more

Commercial whaling Current pop. sizes: Humpbacks 10,000 Fin 56,000 Minke 149,000 Blue 10,000 Pre-exploitation pop. sizes: Humpbacks 240,000 Fin 360,000 Minke 265,000 Blue 200,000 Roman & Palumbi 2003

International Policies International Convention for the Regulation of Whaling, 1946 to regulate global whale stocks (est.’d the IWC) Mission was to set sustainable quotas Not successful Moratorium 1986 (US ended commercial whaling in 1970) Not successful because Membership and conformance is voluntary, not backed up by treaties/no enforcement Quotas were set based on inadequate data Moratorium 1986 (US ended commercial whaling in 1970) Partly successful: 1970 42,480 whales killed, 2005 1,300 whales killed. Japan, Norway, Iceland= uncooperative

Commercial Whaling Despite ban, Japan, Norway, and Iceland kill about 1,300 whales of certain species (minke, fin, humpback) for “scientific purposes”. Although meat is still sold commercially. Figure 12-5