The Blue Whale

The Blue Whale

 Ecology

Catalyzing Change

Gliding toward you through the apparent serenity of the open water, its mottled grey body disguised as blue by the chill ocean, the largest animal on earth makes its presence known. No leaps and bounds are needed to feel the regality of the Blue Whale. Reaching a maximum body length of 36 yards, and a weight of more than 165 tons, this whale is the largest living thing known to man. The Blue Whale is a baleen whale – they take tons of food-laden water into their expandable throat area and discard the water through their baleen plates, leaving only the krill to swallow. This system allows the largest animal on earth to feed on some of the smallest – consuming around 8,000 pounds of krill per day.

National Geographic

The Blue Whale has a “slow” life history, bearing one calf every 2-3 years and living for up to 90 years. They are a migratory species – swimming poleward in the spring to feed, and toward the subtropics in the fall to reproduce and reduce their energy use while fasting.

While this range of movement hasn’t changed in recent years, the population of blue whales have. Before the beginning of industrialized whaling, more than 360,000 Blue Whales roamed throughout every ocean. They were nearly exterminated – with nearly 99% of their population gone – by 1966 when they received protection from the International Whaling Committee (IWC). In 1931 alone, at the height of the whaling period, about 29,000 Blue Whales were killed in one season. Currently there are about 8,000-14,000 Blue Whales left in earth’s oceans.

Human Impacts

Science Blogs: Shifting Baselines

As you can see, hunting by humans has been the main constituent in the decline of the Blue Whale. However, even after hunting was banned humans continued to impact whale populations. Collisions with ships in the 1990s have resulted in the deaths of at least 10 Blue Whales, and potentially a large amount of injuries. Habitat degradation from acoustic and chemical pollution is also a concern. While their diet of plankton makes them less susceptible to accumulations of pesticides and other contaminates, acoustic pollution (such as sonar and underwater noise from military and commercial ship traffic has been known to produce a “startle response.” This startle response 

can result in the loss of feeding time and area and the

excessive burning of precious calories, especially in the winter.

Recovery

Travel Connected

In light of this severe depletion, in 1970 the Blue Whale was listed as “endangered” under the Endangered Species Conservation Act, and when the Endangered Species Act (ESA) passed in 1973 the Blue Whale was listed as “endangered” throughout its range. It is also listed as “depleted” under the Marine Mammal Protection Act.

As part of their status as “endangered,” the government had to create a recovery plan for the Blue Whale. The goal of this recovery plan is to “identify a set of actions that will minimize or eliminate effects from human activities that are detrimental to the recovery of blue whale populations” (National Marine Fisheries Service).

The plan consists of 8 primary steps:

1. Determining the population structure remaining blue whales populations
2. Estimating populations size and monitoring trends in population fluctuation
3. Identifying and protecting essential habitats
4. Minimizing or eliminating human-caused casualties
5. Determining and minimizing effects of vessel interactions
6.  Maximizing efforts to gather information from deceased animals
7. Coordination with state, federal, and international efforts to implement this recovery plan
8.  Establishing a criteria of whether to delist or downlist

What Can You Do?

Despite human assistance in its recovery, the Blue Whale has a long way to go. Just like the first steps in the recovery plan are focused around gaining data, the most important thing you can do to help is spread knowledge. The more people know, the more they can help. So spread the word.

To learn more about Blue Whales or to make a donation to help their recovery, you can visit WWF at http://wwf.panda.org/what_we_do/endangered_species/cetaceans/about/blue_whale/.

World Wildlife Fund (WWF)

References

"Balaenoptera Musculus." NatureServe. Vol. 7.1. Arlington, VA: NatureServe, 2015. NatureServe Explorer: An Online Encyclopedia of Life. Web. 20 Oct. 2015. http://explorer.natureserve.org

National Marine Fisheries Service. 1998. “Recovery plan for the blue whale (Balaenoptera musculus).” Prepared By Reeves R.R., P.J. Clapham, R.L. Brownell, Jr., and G.K. Silber for the National Marine Fisheries Service, Silver Spring, MD. 42 pp.

"Blue Whale." WWF Global. World Wide Fund for Nature, 2015. Web. 25 Oct. 2015. http://wwf.panda.org/what_we_do/endangered_species/cetaceans/about/blue_whale/

"Blue Whale." American Cetacean Society. American Cetacean Society, n.d. Web. 10 Nov. 2015. http://acsonline.org/fact-sheets/blue-whale-2/

"Blue Whale: Federally Endangered." Alaska Department of Fish and Game. State of Alaska, n.d. Web. 13 Nov. 2015. http://www.adfg.alaska.gov/index.cfm?adfg=specialstatus.fedsummary&species=bluewhale

"Blue Whale (Balaenoptera Musculus)." ECOS Environmental Conservation Online System. U.S. Fish & Wildlife Service, n.d. Web. 01 Nov. 2015. http://ecos.fws.gov/tess_public/profile/speciesProfile?spcode=A02M 

Reilly, S.B., Bannister, J.L., Best, P.B., Brown, M., Brownell Jr., R.L., Butterworth, D.S., Clapham, P.J., Cooke, J., Donovan, G.P., Urbán, J. & Zerbini, A.N. 2008. “Balaenoptera musculus.” The IUCN Red List of Threatened Species 2008: e.T2477A9447146. Web. 01 Nov. 2015. http://www.iucnredlist.org/details/2477/0

Blog by Sydney Gallion