Marine Biodiversity Threats and Conservation

Marine Biodiversity Threats and Conservation

Unless otherwise noted, pictures and diagrams are ©Brooks/Cole 2007Unless otherwise noted, pictures and diagrams are ©Brooks/Cole 2007

Over-fishing: 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

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 CommonsTragedy 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”.

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 FishingCommercial 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

Commercial and Recreational Fishing

Fig. 12-A, p. 255

Fish farming in cage

Trawler fishing

Spotter airplane

Sonar

Trawl flap

Trawl lines

Purse-seine fishing

Trawl bagFish school

Drift-net fishingLong line fishing

Lines with hooks

Fish caught by gills

Deep sea aquaculture cage

Float Buoy

Magnuson-Stevens Fishery Conservation and Management Act 1976

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

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

More on Magnuson-StevensMore 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

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

Result of EFH: Gulf of Maine ExampleResult of EFH: Gulf of Maine Example

© NERONMFS

Commercial whaling: another tragedy of the commons

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

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 whalingCommercial whalingCurrent pop. sizes: Humpbacks 10,000 Fin 56,000 Minke 149,000 Blue 10,000

Current pop. sizes: Humpbacks 10,000 Fin 56,000 Minke 149,000 Blue 10,000

Pre-exploitation pop. sizes:Humpbacks 240,000Fin 360,000Minke 265,000Blue 200,000

Pre-exploitation pop. sizes:Humpbacks 240,000Fin 360,000Minke 265,000Blue 200,000

Roman & Palumbi 2003

International PoliciesInternational 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)

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)

Commercial WhalingCommercial Whaling

Despite ban, Japan, Norway, and Iceland kill about 1,300 whales of certain species (minke, fin, humpback) for “scientific purposes”.

Despite ban, Japan, Norway, and Iceland kill about 1,300 whales of certain species (minke, fin, humpback) for “scientific purposes”.

Figure 12-5Figure 12-5