Handout 6-C

What are the dangers facing whales and dolphins?

  • Predators
  • Diseases and parasites
  • Environmental pollution
  • Habitat degradation
  • Commercial fishing, intentional, overfishing, or as incidental by-catch
  • Harassment by well-wishers, whale watching and feeding dolphins from shore
  • Collision by ships
  • Sportsmen hunting
  • Nets
  • Competition of food
  • Noise pollution

    Can dolphins be killed by kindness?

    Yes! Some boat tour operators in places like Florida, South Carolina, and Texas offer charter trips to feed wild dolphins. Beachgoers and fishermen also feed wild dolphins that come close to shore. These dolphins may become dependent on the handouts, most of which is not healthy dolphin food. They have been fed hot dogs, candy bars, beer, and baited fish hooks.

    In a study of six female wild dolphins routinely fed by tourists in western Australia, scientists found that these mothers did a poor job passing on their hunting skills to their offspring. Only five of the seventeen dolphins born to this group survived. Some starved to death; others were struck by boats; others were attacked by sharks.

    What is the most endangered great whale?

    According to authorities at the Stellwagen Bank Information Center, the northern right whale is one of the most endangered mammals in the world. Biologists estimate that 80,000 of these whales once roamed the oceans. But the whales' slow speed and their large stores of blubber and oil (which made them float after they were killed) made them the preferred prey of whaling captains. The name, right whale, was inspired by the fact that they were the "right" whale to catch. Whalers slashed their numbers from tens of thousands to about 50 before they were finally protected by international treaty in 1935.

    After more than 50 years of protection of right whales, biologists estimate that there are still only about 300 northern right whales. The National Marine Fisheries Service states that to avoid extinction, only four right whales per decade can die from other than natural causes. Today, collisions with ships are the leading cause of death of the slow-moving right whales. Since 1970, 14 of 40 documented right whale deaths were caused by collisions with ships. Two other deaths were attributed to entanglement in fishing line or nets.

    http://www.gma.org/marinemammals/human_interaction.html

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