Hobbies And Interests
Whaling
Blue whales were hunted in the beginning of the 19th Century and heavily into the 20th Century. Fishermen hunted blue whales for the meat and oil by boat and harpoons in early years, but as technology advanced and upgraded to ships, the supply and demand for whale rose quickly. This demand resulted in the blue whale hunting accounting for 90 percent of the whaling industry until they were reduced dramatically near extinction. The International Whaling Commission banned commercial whaling for blue whales in 1966 and the blue whale is protected under the Endangered Species Act, the Marine Mammal Protection Act and currently on the International Union for Conservation of Nature Red List of Threatened Species.
Ship Accidents
Soon after whaling was banned, the major threat to blue whales changed to accidents with ships. Ship collisions cause death and severe injury due to their speed and sharp propellers. This is the leading cause of death among the North Atlantic blue whales as they migrate in pods in the Gulf of St. Lawrence Seaway. These shipping lanes consist of heavy ship traffic and are one of the world's busiest seaways along the east coast of the United States and Canada. The Working Group on Marine Mammal Unusual Mortality Events reports that 9 percent of all whales in the Gulf of St. Lawrence have injuries or scars from collisions with ships. Several deaths of blue whales in Pacific waters have been reported due to ship accidents since 1980.
Fishing Gear
Another cause of mortality in blue whales in the North Atlantic and other oceans are the large fishing vessels that use trawls also known as nets dragging them along the bottom of the sea or mid water at specified depths. Blue whales feed on small organisms called krill and plankton and when ingesting, they tend to get entangled in nets by their jaw, flippers and tail. The exact number of whales killed by fishing gear is not known.
Population
The population of the blue whale was nearly depleted by commercial whaling activities worldwide. According to the International Whaling Commission in 2007, as stated by the National Marine Fisheries Service, the Southern Hemisphere population estimates range between 400 and 1,400 whales. In the North Pacific, the current population estimate is a minimum of 3,300 blue whales. The most recent count In the North Atlantic suggests a population of 100 to 555 blue whales there.
Killer whale
The only natural predator other than man is the killer whale, often referred to as the orca. They have been recorded in attacking young blue whales occasionally but often in packs due to the large difference in size. Even with the mother present, orcas are willing to attack and kill young blue whales as a source of food.