Many contaminants are lipophilic, meaning that they dissolve in fats (lipids). Porpoises have blubber, a thick layer of fat underneath the skin that keeps them warm. And that is where contaminants accumulate over time and get stored. Porpoises have a very high metabolic rate, meaning that they need to eat constantly. They can be described as the “hummingbirds of the sea”, relying on a constant intake of nutrients, night and day. If they do not eat for even a short time, they use their fat reserves and the contaminants stored in their blubber get mobilized into their systems.
Some contaminants are believed to affect the immune system of porpoises; they may also have effects on their ability to reproduce.
References and Further Reading
- Corcuera, Javier ; Monzon, Florencia ; Aguilar, Alex ; Borrell, Asuncion ; Raga, J. Antonio (1995). Life history data, organochlorine pollutants and parasites from eight Burmeister’s porpoises, Phocoena spinipinnis, caught in northern Argentine waters. Report of the International Whaling Commission.
- Aguilar, A. ; Borrell, A. (1995). Pollution and harbour porpoises in the eastern north Atlantic: A review. Report of the International Whaling Commission.
- Lockyer, C. (1995). Aspects of the morphology, body fat condition and biology of the harbour porpoise, Phocoena phocoena, in British waters. Report of the International Whaling Commission.
- Jepson, Paul D. ; Bennett, Peter M. ; Deaville, Robert ; Allchin, Colin R. ; Baker, John R. ; Law, Robin J. (2005). Relationships between polychlorinated biphenyls and health status in harbor porpoises (Phocoena phocoena) stranded in the United Kingdom. Environmental Toxicology and Chemistry.
- Sinéad Murphy ; Jonathan L Barber ; Jennifer A. Learmonth ; Fiona L. Read ; Robert Deaville ; Matthew W. Perkins ; Andrew Brownlow ; Nick Davison ; Rod Penrose ; Graham J. Pierce ; Robin J. Law ; Paul D. Jepson (2015). Reproductive Failure in UK Harbour Porpoises Phocoena phocoena: Legacy of Pollutant Exposure?. PLOS ONE.
- Hall, Ailsa J. ; Hugunin, Kelly ; Deaville, Robert ; Law, Robin J. ; Allchin, Colin R. ; Jepson, Paul D. (2006). The risk of infection from polychlorinated biphenyl exposure in the harbor porpoise (Phocoena phocoena): A case–control approach. Environ Health Perspect.
- Beineke, Andreas ; Siebert, Ursula ; McLachlan, Michael ; Bruhn, Regina ; Thron, Kristina ; Failing, Klaus ; Müller, Gundi ; Baumgärtner, Wolfgang (2005). Investigations of the potential influence of environmental contaminants on the thymus and spleen of harbor porpoises (Phocoena phocoena). Environmental Science & Technology.