Threatened marine life

Posted: 30 June 2006

Only 4.2 per cent of the species on IUCN's Red List of Threatened Animals are marine. While this might seem like a small number, in reality it reflects the fact that science knows very little about the ocean's inhabitants.

Only an estimated 15 per cent of all marine species have been described, let alone assessed for population size, distribution or status.

Of over 300 marine species listed in the categories of critical, endangered or vulnerable, some 40 per cent are large, well-studied and relatively well known mammals and birds. The Red List also contains over 700 species of fish, over 400 species of crustaceans and 900 species of molluscs, most of which are marine species.

  • Coral reefs throughout the tropics are endangered, as are such fish species as humphead wrasses and southern bluefin tuna.
  • Whales are endangered, especially the blue whale (from 300,000 to fewer than 5,000) and the pygmy blue whale (only a few thousand are thought to survive).
  • Each year, illegal longline fishing kills over 300,000 seabirds, including 100,000 albatrosses. 19 out of 21 albatross species are now threatened with extinction.
  • Populations of large fish with high commercial value, such as tuna, cod, swordfish and marlin, have declined by as much as 90% in the past century.
  • The orange roughy, a commonly targeted deep sea fish, matures after around 32 years. A specimen of this species was recently found to be approximately 240 years old meaning that it was born about the time of Napoleon Bonaparte’s birth.