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

2. 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

3. 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)

4. 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

5. Commercial and Recreational Fishing
Start here with C block Thursday

6. 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

7. 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)

8. 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

9. Result of EFH: Gulf of Maine Example
© NERONMFS

10. Commercial whaling: another tragedy of the commons
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

11. 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

12. 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: ,480 whales killed, ,300 whales killed.
Japan, Norway, Iceland= uncooperative

13. 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