Blue Whale

Blue Whale

Blue whales, part of the Eastern North Pacific population ranging from Alaska to Costa Rica, can sometimes be spotted off Oregon, but normally 10 miles offshore or greater. They are thought to be among the most endangered of the great whales. The Marine Mammal Institute, Oregon State University (OSU) reports that the whaling industry destroyed 97% of the world’s population, adding that more than 360,000 blue whales were killed in the Antarctic alone. By the 1960s, they were nearly extinct.

Why would the blue whale, or any whale species that is not limited to Oregon cause concern to this state? Though all states, and indeed – all nations, would be wise demonstrate concern for offshore species survival, Oregon is one of the coastal states that could significantly impact species with a range that includes waters off our shore. This places responsibility upon Oregon to consider potential impact of development. Oregon is known for our commitment to a clean environment, yet must extend our concern to species beyond our shoreline that can be affected. Careful monitoring and studies of the blue whale is in our best interest.

Sea-surface temperature (SST) fronts are integral to pelagic (open ocean) ecology in the North Pacific Ocean, making it necessary to learn how these features influence the behavior of endangered and highly migratory species. It is documented and confirmed that rising ocean temperatures are affecting ocean ecology. What can Oregon do to minimize or at least delay the damage?

Current threats to blue whales

  • Unsustainable fishing practices – the increasing human demand for fish prompts more fleets on the water while the fish availability continues to drop. Without better management, many fish will be unable to sustain a healthy population. The end result is loss of these fish for humans and whales.
  • Entanglement in fishing nets.
  • Oil and gas industries pose multiple threats to cetaceans.
    • Habitat loss
    • Hearing damage from seismic tests (a deaf whale is a dead whale)
    • Pollution
  • Pollution
    • Cetaceans (marine mammal of the order Cetacea; a whale, dolphin, or porpoise) are known to be at risk from anthropogenic (originating in human activity, particularly used describing environmental pollution and pollutants) contaminants due to their longevity and high trophic position (high position in the food chain – more info).
    • Studies of whale and dolphin tissues from around the world show significant levels of persistent organic pollutants and endocrine disrupting chemicals. Testing a blue whale killed by a ship strike in 2007, the contaminants found included DDT, chlordanes, PCBs, and polybrominated diphenyl ethers in addition to pesticides, flame retardants, and mercury. DDT was banned 30 years before this animal was born, but it was still exposed to DDT over its entire lifetime. Pollutants like DDT and mercury are known to cause a host of problems, including developmental disorders and thyroid issues.
  • Ship strikes
  • Underwater noise – shipping lanes exclude cetaceans from valuable habitat as they avoid excessively noisy areas. Sound travels differently under water than through air; it travels five times faster, travels farther – especially in deeper waters, and is because water is denser than air, it conducts sound better – so underwater sounds are louder. A normal conversation is about 60 decibels (dB). A lawnmower is 90 dB, a rock concert is 120 dB, and a gunshot is 140 dB. For humans, enough exposure to 85 dB can damage hearing. In the ocean, sonar pulses can top 200 dB and large ship engine sound exceed 180 dB. In areas with high shipping traffic, noise levels have doubled each decade since the 1960s. In addition to habitat loss, there is significant concern that noise levels interfere with cetacean sonar as well as their critically needed ability to communicate with their species.
  • Climate change impacts krill – the blue whale’s major prey.

Quick facts

  • The blue whale is not only the largest animal on the planet, but also the largest animal ever known to have existed – weighing as much as 200 tons (equal to 33 elephants). Its heart is the size of a Volkswagen Beetle. Average length between 70 – 80 feet; Average weight between 70 – 100 tons.
  • Blue whales are the loudest animals on Earth – though many of their vocalizations are beyond the range of human hearing. Their calls can reach 188 dB and their low frequency whistle can be heard for hundreds of miles.
  • Appearance: Very long, streamlined body, two blowholes with a very large slash guard in front, stubby dorsal fin, 55 – 88 throat grooves which expand when feeding, and blue-gray skin color dotted with whale barnacles.
  • Their primary and preferred diet is krill (euphausiids, tiny shrimp-like crustaceans). While other prey species, including fish and copepods, may be part of the blue whale diet, these are not likely to contribute significantly.
  • The stomach of a blue whale can hold one ton of krill. It needs to eat about four tons of krill each day.
  • Weight: up to 400,000 pounds (200 tons), typically 90 – 150 tons.
  • Length: up to almost 110 feet, typically 70 – 80 feet.
  • Blue whales are largest in the Antarctic.
  • Lifespan: Unknown; scientists believe they live at least 80 years.
  • Blue whales have no teeth, but rather 300 – 400 baleen plates which it uses to strain food from the ocean water.
  • Blue whales dive for 10 to 20 minutes at a time.
  • Sexual maturity is reached between 5 – 10 years. Females give birth every two to three years to one calf. Gestation is 10 – 12 months. The average calf is 23 feet long, weighing about 4,400 pounds, and is fed by its mother for 7 – 8 months.
  • Although there are reports of as many as one quarter of the blue whales ID’d in Baja bear scars from orca attacks, though those attacks are deemed rarely successful.

Sources

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“American Cetacean Society Fact Sheet.” Blue Whale. Web. 23 July 2015.http://web.archive.org/web/20070927223808/http://www.acsonline.org/factpack/bluewhl.htm.

“Blue Whale (Balaenoptera Musculus).” :: NOAA Fisheries. Web. 23 July 2015. http://www.fisheries.noaa.gov/pr/species/mammals/whales/blue-whale.html.

“Blue Whale Earwax Reveals Pollution Accumulated Over a Lifetime.” Smithsonian. Web. 23 July 2015. http://www.smithsonianmag.com/science-nature/blue-whale-earwax-reveals-pollution-accumulated-over-a-lifetime-7577513/?no-ist.

“Blue Whales, Balaenoptera Musculus.” MarineBio.org. Web. 23 July 2015. http://marinebio.org/species.asp?id=41.

“Blue Whales, Blue Whale Pictures, Blue Whale Facts – National Geographic.” National Geographic. Web. 23 July 2015.http://animals.nationalgeographic.com/animals/mammals/blue-whale/.

“Blue Whale Contaminant Analysis.” Blue Whale Contaminant Analysis. Web. 23 July 2015. http://whale.wheelock.edu/bwcontaminants/welcome.html.

Bortolotti, Dan. Wild Blue: A Natural History of the World’s Largest Animal. First ed. Thomas Dunne, 2008. Print.

“Crustaceans.” Crustaceans. Web. 23 July 2015. http://www.mesa.edu.au/crustaceans/crustaceans07.asp.

“FAO Fisheries & Aquaculture – Aquatic Species.” FAO Fisheries & Aquaculture – Aquatic Species. Web. 23 July 2015. .

“Marine Species Identification Portal : Bentheuphausia Amblyops.” Marine Species Identification Portal : Bentheuphausia Amblyops. Web. 23 July 2015. http://species-identification.org/species.php?species_group=euphausiids&menuentry=inleiding&id=2&tab=foto.

Monk, Alissa, Kate Charlton-Robb, Saman Buddhadasa, and Ross Thompson. “Comparison of Mercury Contamination in Live and Dead Dolphins from a Newly Described Species, Tursiops Australis.” PLoS ONE. Public Library of Science. Web. 23 July 2015. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4138083/.

Small, George L. The Blue Whale. New York: Columbia UP, 1971. Print.

Tarpy, C. “Killer Whale Attack!” National Geographic 1979: 542-45. Print.

“Understanding Ocean Acoustics.” NOAA Ocean Explorer Podcast RSS. Web. 23 July 2015.http://oceanexplorer.noaa.gov/explorations/sound01/background/acoustics/acoustics.html.

“Underwater Racket.” Student Science. Web. 23 July 2015. https://student.societyforscience.org/article/underwater-racket.