The blue whale (Balaenoptera musculus) is a species of baleen whale known as the largest animal on Earth. They can grow to be over 100 feet long and can weigh up to 165 tons. Blue whales are found in all oceans and can occupy a wide variety of habitats, from pelagic environments to offshore environments (Clapham et al. 1999).
Up until the 19th century, blue whales were generally immune from whaling. Not only were they substantially large animals, they were also very quick and agile and were difficult to catch. However, the invention of the steam engine and explosive harpoon allowed whalers to regularly catch this animal (Clapham et al. 1999). During the early 20th century, a whaling ground was opened in the Southern Ocean of which blue whales became the primary target species. Over 360,000 blue whales were kill during that century in the Antarctic region alone. Finally in 1966, the International Whaling Commision [IWC] banned commercial whaling for blue whales (Reilly 2013). Even so, former fleet members of the USSR navy continued to exploit this and other species until the 1970s. In 1986, the species was listed as ‘endangered’ by the International Union for Conservation of Nature [IUCN] (Clapham et al. 1999).
Almost 30 years later, the status of the species has not changed (Reilly 2013). Although commercial whaling is no longer a concern, there are many other threats to this species that have garnered attention over the years. Today, anthropogenic noise, fisheries interactions, and ship strikes all threaten the status of this species (Reilly 2013). For this paper, I will be focusing on the effects ship strikes have on the blue whale population.
Habitat and Distribution
Blue whales are found in all oceans worldwide, occupying both artic and tropical waters (Barlow et al. 2000). They feed primarily on krill, so their migratory patterns coincide with prey distribution. In order to accurately assess the status of the stock, the population has been divided into sub-populations by ocean.
The blues whales in the North Atlantic region occupy the area between the Scotian Shelf and the eastern Canadian coast in the summer. Although there is no data available as to where this sub-population resides in the winter, there have been a few sightings in the southern North Atlantic region (Clapham et al. 1999).
The sub-population in the North Pacific has been divided into two groups: eastern North Pacific and western North Pacific. In the eastern North Pacific, the blue whales spend their summers in the Gulf of Alaska, around the coast of California, and the southern North Pacific region. In the winter, they stay mainly in the areas around Mexico and Central America (Barlow et al. 2000). In the western North Pacific, blue whales can be found in the Gulf of Alaska and in waters near the Aleutian Islands in the summer. Their distribution is relatively unknown in the winter, but there have been sighting of blue whales near Hawaii (Clapham et al....