ENVIRONMENT

Vaquitas’ numbers have dropped precipitously because of illegal gillnet fishing. (Nat Geo News)

Use our resources to learn a little about porpoises.

Discussion Ideas

• The short Nat Geo News article attributes the dwindling population of vaquitas to illegal gillnet fishing. What are gillnets?
  • According to the good folks at the Safina Center, “a gillnet is a large net wall that hangs vertically in the water. Floats line the top of the net, while weights line the bottom of the net. The net is virtually transparent, so fish and other animals are unable to see it … The mesh is designed to be large enough for the head of the fish to pass through, but not its body. As a result, when fish swim into the net they are entangled by their gills.”

• Why are vaquitas being fished so heavily?
  • They’re not. Vaquitas are bycatch in the lucrative shrimp and totoaba fisheries. Totoaba are large, critically endangered fish. The delicate swim bladders of totoaba are in high demand in Asia, and fishermen may receive up to $8,500 per kilogram of totoaba swim bladder.
    • Vaquitas are about the same size as totoaba, get their heads stuck in gillnets and drown.

• What is being done to help protect the vaquita?
  • Conservation measures include everything from “imposing a ban on gillnet fishing in the area; to surveillance by the Mexican government, military, and environmentalists; to compensation for local fishermen [in exchange for not fishing] in that area.”

• What else can be done to protect the vaquita?
  • Experts recommend “a more stringent … fishing ban, more support for vaquita-safe fishing gear, and cooperation among Mexico, the United States, and China to crack down on totoaba poaching.”
    • Vaquita-safe fishing gear includes small trawl nets that drag across the seafloor.

• “We are on the brink of driving the fifth marine mammal species to extinction in modern times,” says Omar Vidal, the CEO of WWF-México. What are the four extinct marine mammals driven to extinction in modern times?
  • Steller’s sea cow went extinct in the mid-1700s. Steller’s sea cow was related to manatees and dugongs, and indigenous to the North Pacific Ocean.
  • The Atlantic gray whale went extinct in the 1700s. The Atlantic gray whale, a subspecies or distinct population of the gray whale, was indigenous to the North Atlantic Ocean.
  • The Caribbean monk seal went extinct in the 1950s. The Caribbean monk seal was related to the Hawaiian monk seal and the Mediterranean monk seal, both of which are critically endangered today.
  • The baiji went extinct in the early 2000s, although there have been reported sightings ever since. The baiji, also called the Chinese river dolphin, is indigenous only to the Yangtze River.

TEACHERS TOOLKIT

Nat Geo: World’s Smallest Porpoise Is on the Verge of Extinction

Nat Geo: Is it a Porpoise or a Dolphin? graphic

NOAA Fisheries: Vaquita and Vaquita Overview