Fisheries issues of the world ocean

Fisheries issues of the world ocean

Figures, Facts and Factors

Coastal Facts

• Coastal area = 20% of land area, but 39% of world population lives within 100 km of it

• 19% of land within 100 km of coastal areas is altered to urban or agricultural use

• 57% of continental shelf of fishing nations is trawled (8.8 million km2)

• Relatively small spatial units, often submerged, difficult to assess with coarse-scale global sensors

What’s happening in fish habitat?

Chemical contaminant issues

http://www.us-ecosystems.org/coasts_oceans/synthetic_organics/

Global climate change issues

• Severe storm events

• Increased agricultural runoff

• Accelerated eutrophication

• Changing thermal niches

• Loss of coastal wetlands for spawning

• Expanded ranges of non-native organisms

Overfishing

“Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change” (J.B.C. Jackson, et al, 2001. Historical overfishing and the collapse of coastal ecosystems. Science 293, 5530. 629-637.)

Historical sequence of human disturbances affecting coastal ecosystems

Jackson, et al, 2001

What’s happening in fishing?

Food web changes before and after overfishing the historical ecosystems

Jackson et al, 2001

A Fishery Story: The Downeaster Alexa

• Song by Billy Joel, 1989• Changes in striped bass commercial fishery• Investigation of contributing factors

– Overfishing– Global climate change– Predators, other biotic interactions– Water quality– Disease