Overharvesting

hunting - see the results of bison hunting
     predator control
     illegal harvesting and trade

Overfishing is the greatest threat to the biodiversity of the world’s oceans overfished. For the major fisheries—those in the Atlantic, the Pacific, and the Gulf of Mexico—two-thirds of the stocks were overfished.

http://www.zo.utexas.edu/faculty/sjasper/images/tonsoffish.jpg

Bycatch is just as harmful as the actual fishing.

http://www.zo.utexas.edu/faculty/sjasper/images/bycatch.jpg

http://www.zo.utexas.edu/faculty/sjasper/images/bycatchgraph.jpg

http://www.zo.utexas.edu/faculty/sjasper/images/driftnet.gif

http://www.zo.utexas.edu/faculty/sjasper/images/driftnets.jpg

http://www.zo.utexas.edu/faculty/sjasper/images/longline.jpg

Whaling

The first whalers likely took their prey close to shore. Right whales were the “right” whales to take because they are large and slow-moving, feed near the surface and often inshore, float to the surface when harpooned, and were of considerable commercial value for their oil and baleen (see whalebone). Whalers then moved on to species that were more difficult to kill,.

In the late 1800s, steamships replaced sailing ships, and gun-launched exploding harpoons replaced hand-thrown lances. Gradually, all species of whales were hunted.

Ship collision, bycatch and illegal trade

Seven out of the 13 great whale species are still endangered or vulnerable after decades of protection. Despite a moratorium on commercial whaling and the declaration of virtually the whole of the Southern Ocean as a whale sanctuary, each year over 1,000 whales are killed for the commercial market.

Logging

Similar cases of overharvested species are found in terrestrial ecosystems. For example, even when forests are not completely cleared, particularly valuable trees such as mahogany may be selectively logged from an area, eliminating both the tree species and all the animals that depend on it. Another example is the coast sandalwood, a tree endemic to the Hawaiian Islands that was almost completely eliminated from its habitats for its wood and fragrant oil.