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Volume 39 Issue 8 • June 25-July 1, 2009
now in our 39th season

A Fine Line

by Dr. Sarah D. Oktay
Managing Director UMass Boston Nantucket Field Station

This week's article is in honor of the showing of “The Cove” as the centerpiece film (and winner of the audience favorite award) at last week's Nantucket Film Festival.  The film is not only compelling but expertly directed, scored, and edited, and clearly shows the heartbreakingly stupid practice of eating mercury-laden dolphin meat and the brutal and unnecessary deaths of hundreds of dolphins and porpoises to provide this meat to unwary Japanese consumers and to obtain new aquatic victims for training in the dolphinarium industry.  Marine biologists, oceanographers, and conservation ecologists have been aware of the sticky bioethical nature of “marine world” parks for years.  No one in my field would advocate attending one of these parks or even worse, one of the “swim with the dolphins” horror-shows.  Although these ventures have helped educate many people about marine mammals such as dolphins and whales, they walk a fine line between exploitation and education, and their usefulness and intrinsic humaneness is a long-standing issue in the marine science realm. 

Photo courtesy of Bob Miller

This dilemma is played out in zoos and nature centers across the country, but the similarity or evolutionary “closeness” of marine mammals to humans makes their captivity and care seem a more pressing issue.  Where I and my colleagues have failed is in educating the public on the exploitative and unnecessary function of sea life parks which use captive cetaceans to perform silly tricks.  Several of the more responsible aquariums and marine educational faculties strictly rehabilitate animals for release back into the wild or keep only those animals which cannot be released in tanks with a minimum of fanfare, showmanship, and hoopla.  But their kindred have realized a financial bonanza in exploiting bottlenose dolphins and orcas for the entertainment and “ecotourism” (used very loosely) industry, and this need for more trained animals has led to a black (or gray) market for their capture and distribution.

Before the outrage, let's learn a little about what species we are talking about.  Starting from the top of the evolutionary tree and dipping into the Wikipedia mailbag, we find that marine mammals are a diverse group of roughly 120 species of mammals that are primarily ocean-dwelling or depend on the ocean for food.  They include the cetaceans (whales, dolphins, and porpoises), the sirenians (manatees and dugong), the pinnipeds (true seals, eared seals and walrus), and several otters (the sea otter and marine otter).  The polar bear, while not aquatic, is also usually considered a marine mammal because it lives on sea ice for most or all of the year.

“Cetus” is a Latin word most commonly translated as the word for "whale" although its original meaning, "large sea animal," was more general.  It comes from the Ancient Greek (kētos), meaning "whale" or "any huge fish or sea monster."  In Greek mythology, the sea monster Perseus defeated was called Ceto, which is depicted by the constellation of Cetus ( for a Moby Dick connection go to  Cetology is the branch of marine science associated with the study of cetaceans. The order Cetacea contains about ninety species, all marine except for four species of freshwater dolphins.  The order is divided into two suborders, Mysticeti (baleen whales) and Odontoceti (toothed whales, which includes dolphins and porpoises).  The species range in size from the Commerson's Dolphin and Tucuxi, which are smaller than a human, to the Blue Whale, the largest animal that has ever lived.  As mammals, cetaceans have characteristics that are common to all mammals:  they are warm-blooded, breathe in air through their lungs, bear their young alive and suckle them on their own milk, and have hair, although very little of it.  I was pretty enchanted and a little surprised to find out that newborn dolphins have little whiskers when they are borne that quickly fall off.

Photo courtesy of Bob Miller

For this article we will be concentrating on the smaller cetacean species; i.e. “Flipper” and his (actually her) pals.  There are a variety of dolphin species that migrate close enough to be encountered in the waters around Nantucket and the Marine Mammal Stranding Team is often dispatched to assist in cetacean strandings.  The Cape Cod Stranding team ( reports that common stranded toothed whales include Atlantic white-sided dolphins, common dolphin, pilot whale, and the white beaked dolphin. They have to deal with a large number of mass strandings in which the highly social animals tend to strand in shallow water with most of the members of their pod.  Locally we see the white sided dolphin, the common dolphin, pilot whales, Risso's dolphins, striped dolphins, pygmy sperm whales, and harbor porpoises. You can see a video by Plum TV at that clearly shows the long days and hard decisions that are made each time we respond to a marine mammal stranding event.  There are many factors suspected to cause or induce strandings, from acoustic damage from naval testing to confusion from pollutant poisoning to simple ailments that affect toothed whales the same as other mammals like infections and tumors.  Our narrow harbor and creeks also make it very difficult for dolphins to escape if they come into Nantucket Harbor greedily chasing some food; the long skinny stretch of the harbor and incursion of multiple cuspate spits causes some species to ping pong back and forth trying to find the exit and a tide that works for their escape. There are no dolphin gas stations to pull over and ask for directions.

Back to some more details about the movie, which I hope you will see and encourage your friends to see (info at and  In Taiji, Japan, several thousand dolphins are slaughtered during a hunt season that stretches from September through the end of April.  Throughout Japan, it is estimated that approximately 23,000 dolphins and porpoises are killed annually.  I have seen several dolphins lose their battle to live up close and personally as a member of the Nantucket Marine Mammal Stranding team, so the movie's graphic nature did not move me as deeply as it might most people; but it clearly shows the atrocity of the local fishermen’s actions to round up and kill the dolphins for cheap meat when they aren't chosen for a lifetime of sea life shows.  “The Cove” refers to an natural inlet near a beach that is easily cordoned off, where confused dolphins are corralled by fishermen pounding sticks and rods during an unnerving portion of the movie.  Director Louie Psihoyos recruits a team of highly trained divers, high tech camera wizards, and various other specialists (my favorite and the one I need is the rock show organizer) to instrument the Cove under the cover of night and outside of the prying eyes of the fishermen protecting the secret of “The Cove”.

One of the obvious “bad guys” in the film is the International Whaling Commission. A quick perusal of their website ( shows that they are primarily concerned with the larger whale species.  To see tiny island nation-states such Antigua & Barbuda being bought out by the Japanese coalition to vote their way on issues related to Japanese whaling is truly disheartening.

Why are these roundups conducted?  To find animals to be shipped world-wide for use in marine life theme parks and dolphin “petting zoos.”  Want to see what not to do next time you are in Florida?  Check out  My brother and his family went down to one of these “swim with the dolphin” programs and brought pictures back to show me; you can imagine my expression.  I did let slip some of the observed randiness of many dolphins in the wild regardless of species match, which usually slows down most people.  Here is a link to a recent text called “Dolphinaria in Mexico” that explores some of the animal rights issues associated with using captive cetaceans:

It is also interesting to note, that not unlike humans, some dolphin species also have many characteristic behaviors that are only recently being documented that are not so nice, such as going to war, forming gangs, kidnapping other pods females, forming treaties, starting to sound like a recent episode of some show on cable, right?  Treatment and rehabilitation of marine mammals needs to take into account these behaviors and associated cognitive abilities.

Fortunately, there are some success stories. According to, the United Kingdom is a “captive dolphin and whale free zone.” Since the early 1990s, there have been no captive dolphins or whales on display in the UK, following the closure of the last remaining facilities.  The site has some excellent information on captivity myths and realities and also recognizes the atrocities of dolphin dive hunts.

This interesting site: briefly talks about both sides of a whaling debate and invites the reader to consider carefully the pros and cons of whaling.  I have yet to read such a concise and thoughtful framing of the argument that forces students studying bioethics to actually argue their case logically. In addition, it lists several useful links for further study.

I recently read an article that documented that the Japanese government could not even begin to give away the whale meat being brought into the country and that attempts to get them inserted into school lunches was not going well as young Japanese had lost the taste for whale meat.  Like many other top predators that eat meat, dolphins concentrate pollutants into their tissues from the hundreds of small fish they ingest.  Scientists have published hundreds of studies documenting mercury contamination in a variety of animals from the famous female Florida panther killed by mercury in 1989 to large fish, whales, and dolphins.  Coal-burning power plants are the largest human-caused source of mercury emissions to the air in the United States, accounting for over 40 percent of all domestic human-caused mercury emissions.  The EPA has estimated that about one quarter of U.S. emissions from coal-burning power plants are deposited within the contiguous U.S. and the remainder enters the global cycle.  Mercury in the air eventually settles into water or onto land where it can be washed into water.  Once deposited, certain microorganisms can change it into methylmercury, a highly toxic form that builds up in fish, shellfish and animals that eat fish.  Fish and shellfish are the main sources of methylmercury exposure to humans.

At one can find two links to peer reviewed papers on mercury contamination that include samples from dolphin and whale meat taken from subjects involved in Taiji.  I found them pretty clear, until I realized I did trace metal testing and wrote papers on the subject as an undergrad, so I might be a bit ahead of the curve, so I figured perhaps I'd synthesize what those papers said. In a nutshell that is almost Twitterable: dolphins are apex predators whose bodies contains 5 to 5000 times the daily limit of mercury allowable in Japanese food.  Most of this is found in the liver, so don't eat it.  Thankfully, it is not usually in the methylmercury form.

This web site, lists several different categories of seafood and details which ones have lower amounts of mercury and are harvested or farmed using “eco-friendly” methods.  It is important to remember that there are many benefits to eating fish such as their high omega-3 fatty acids content.  Often the benefit to the health of your heart is much much greater than any cancer or poisoning risk. The health risks link here is even more specific on the number of meals per month that can be consumed.  Sadly, wild striped bass is included as a fish to avoid.  In the movie, they only addressed mercury concerns and did not bring up PCBs or other carcinogens.

Last but not least, I like to give special credit where credit is due. I was reading a review of the film on the Huffington Post ( in which I was reminded of a brief comment during the Q&A after the film that Jim Clark was one of the primary backers of the film.  Clark is a dive enthusiast and the founder of Silicon Graphics, Netscape, and WebMd—let's hear it for people who have “done well” and now “do good.  This is the first film product from the fledging non-profit, the Oceanic Preservation Society ( I think the passion of the director, Louie Psihoyos, Charles Hambleton (Clandestine Operations), and Ric O'Barry definitely steal the show.  And we should thank Scott Leonard and Michelle Perkins who are members of the Nantucket Marine Mammal Conservation Program (separate entity from the Nantucket Marine Mammal Stranding Team - for their tireless promotion effort for the film. This is a film that makes you think and, I hope, inspires you to action.

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