Secret Lives of Whales
 

Scientists are studying the impacts of industrial toxins on sperm whales.

Sperm whales worldwide

Summary

  • Some environmental toxins can accumulate in the body and cause health problems
  • Sperm whales are ideal candidates to study the effects of these toxins in the wild

here is a group of toxins that can be found in every ecosystem on Earth. These chemicals can accumulate in the body and cause health problems - even in small doses. Scientist Roger Payne is studying their effects on sperm whales.

Persistent Poisons

Persistent organic pollutants (POPs) are a group of harmful chemicals that are found in small amounts all around the world, even Antarctica. This is because they break down very slowly and are easily transported in water and air. These toxins were originally created for industrial purposes, unintentionally as byproducts or in the breakdown of other chemicals. Examples include DDT, PCBs, and dioxins.

POPs have negative effects on:

  • The endocrine system
  • The reproductive system
  • The immune system
  • The nervous system
  • Skin
  • Liver
  • Thyroid
  • Weight loss
  • The neurobehavioral system

Mice to Whales

The effects of these toxins are mainly studied using rats and mice. However, to uncover how they act on organisms in the wild scientists went from studying tiny animals to huge – Sperm whales.

POPs are found dissolved in the ocean in tiny amounts (parts per million to parts per trillion) and marine organisms can be thought of as swimming in a soup of extremely diluted toxins. The concentration of this soup is often too low to cause health problems. However, these chemicals pose a greater threat to marine predators because of a process called bioaccumulation.

Bioaccumulation

Many persistent organic pollutants are stored in fat and accumulate in the body over time. When predators eat prey that have accumulated these toxins they can build up high levels in their own fat. This process of bioaccumulation can build up concentrations that cause health problems.

This threat is magnified for predators that eat other predators, such as the Sperm whale (Physeter catodon), because they eat animals who are likely to have accumulated a high concentrations of these chemicals.

Why Study Sperm Whales

Sperm whales are them especially vulnerable to persistent organic pollutants, because they are:

  • High on the food chain.
  • Large
  • Long lived
  • Mammals

High on the food chain
Sperm whales are at the top of the food chain and eat other predators. Bioaccumulation might cause very high levels of these toxins to build up.

Large size
Larger animals tend to have slower metabolisms and take longer to rid themselves of these chemicals.

Long lives
Sperm whales have a long time to accumulate toxins because they live at least 60-70 years.

Mammals

These chemicals can be passed from a mother to her offspring through milk. Marine mammals can start life with an (un)healthy dose of toxins.

The Voyage of the Odyssey

Roger Payne of the Ocean Alliance led a 5 year round-the-world voyage on the research vessel Odyssey. During that time, scientists took skin samples from sperm whales and tested them for toxins.

Researchers gathered over 1000 samples during the Voyage of the Odyssey. They collected so much data that scientists are still working on this material. However, preliminary results from this expedition find DDT and PCB in every whale sample they have tested. What this means for these animals remains to be seen.

Find out more about the featured researcher – Roger Payne

References

Bohannon, J. (2004, June 11). Roger Payne profile: A toxic odyssey. Science. Retrieved 14 May 2009 from http://www.sciencemag.org/cgi/content/full/sci;304/5677/1584

EPA. (2009, April 2). Persistent Organic Pollutants: A global issue, a global response. US environmental protection agency. Retrieved 14 May 2009 from http://www.epa.gov/oia/toxics/pop.htm

Godard, C. et al. (2003). Preliminary report on the sperm whale data collected during the Voyage of the Odyssey. PBS. PDF retrieved 14 May 2009 from http://www.pbs.org/odyssey/voyage/oa_iwc_2003.pdf

Godard, C. et al. (2004, March 31). Induction of Cetacean Cytochrome P4501A1 by b-Naphthoflavone Exposure of Skin Biopsy Slices. Toxicological Sciences 80: 268–275. PDF retrieved 14 May 2009 from http://toxsci.oxfordjournals.org/cgi/reprint/80/2/268

Kelly, B. et al. (2007, July). Food web–specific biomagnification of persistent organic pollutants. Science 317 (5835) 236 – 239. Retrieved 14 May 2009 from http://www.sciencemag.org/cgi/content/full/317/5835/236

LOE. (2008, February 15). Bad news from the blubber. Living on Earth. Retrieved 14 May 2009 from http://www.loe.org/shows/shows.htm?programID=08-P13-00007#feature6

MarineBio.org. (2007, October 30). Physeter catodon, Sperm Whale - MarineBio.org. Retrieved Thursday, July 16, 2009, from http://marinebio.org/species.asp?id=190

O'Hara, T & O'Shea, T. (2005). Assessing impacts of environmental contaminants. In Marine mammal research: conservation beyond crisis (Reynolds, J et al eds.). The Johns Hopkins University Press: Baltimore.

PBS. (2005) Voyage of the Odyssey. Public Broad casting company. Retrieved 16 July 2009 from http://www.pbs.org/odyssey/

Reeves, R. et al. (2003). Guide to Marine Mammals of the World. New York: A.A. Knopf.

Ross, P. (2005, December 8). Fireproof killer whales (Orcinus orca): flame-retardant chemicals and the conservation imperative in the charismatic icon of British Columbia, Canada. 63: 224-234. PDF retrieved 14 May 2009 from http://pubs.nrc-cnrc.gc.ca/rp/rppdf/f05-244.pdf

Rowe, C. (2008, July 1). "The calamity of so long life": Life histories, contaminants, and potential emerging threats to long-lived vertebrates. BioScience 58 (7): 623-631. Retrieved 14 May 2009 from http://www.accessmylibrary.com/coms2/summary_0286-34998904_ITM

Wise laboratory. (2008, March 27). Sperm whale toxicology studies. Wise laboratory of environmental and genetic toxicology. Retrieved 14 May 2009 from http://usm.maine.edu/toxicology/research/sperm_whale.php
 
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