Marine Mammals as Sentinel Species for Oceans and Human Health

Bossart, G.D. 2006. Marine Mammals as Sentinel Species for Oceans and Human Health. Oceanography, Volume 19, Number 2, a quarterly journal of The Oceanography Society.

This article discusses the importance of marine mammals as a sentinel for human health and ocean health. Marine mammals are beneficial at helping to identify changes in the environment due to long life spans, feed at high trophic level, and extensive fat storage that help with anthropogenic toxin analysis. Marine mammals are also beneficial in the way that humans find that they can connect with them due to their charisma. The relationship between threats to marine mammals and consumption, population growth and behavioral patterns of humans are directly correlated.

The research question that is being asked is what are the diseases and threats that marine mammal sentinel’s are warning us about? In this paper they discuss the sentinel species as being the Atlantic Bottlenose Dolphin (Tursiops truncatus), West Indian Manatee(Trichechus manatus latirpstris), California Sea Lion (Zalophus californianus), and the Sea Otter (Enhydra lutris nereis).

Some of the different kinds of human health threats that have been determined by analyzing marine mammal biopsies and blood samples are infectious diseases, pollutants and harmful algal blooms.

California Sea Lions that have been founded stranded have had necropsies done and found that around 20% have urogenital cancer which is caused by herpes virus and contaminants due to PCBs and DDTs. The occurrence of these contaminants is unnerving due to the fact that Sea Lions feed and live in highly human populated areas up and down the coast. An analysis was done on a population of Sea Otter’s and found that 38% on the California coast have toxoplasmosis. Toxoplasmosis is a parasitic disease caused by the protozoan Toxoplasma gondii. These protozoans can survive and life in foods that are not only eaten by Sea Otters but by humans as well. Heavy metal pollution can be analyzed in the fatty tissues of animals such as Polar bears, Bowhead Whales and Bottlenose Dolphins. Pathologic analysis was conducted on Dolphins and manatees and was found that the emergence and resurgence of diseases can be caused by environmental distress.

Harmful Algal Blooms have been observed to significantly impact high numbers of sea lions, manatees and dolphins. There are numerous types of toxins that cause the poisoning of shellfish, which in turn are eaten by marine mammals and then are found washed up and beached due to neurotoxins.

Statistical analysis was not used in this article because genetic testing was primarily used also because it was a case study and not an overall scientific article.