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Urban Marine Mammals

by Sharon Young

When most people think of marine mammals, they picture large animals living peacefully in a vast ocean. Few people think of whales, seals, or manatees living near coastal cities and developed areas. But you might be surprised at the many urban environments to which these animals have adapted. Indeed, because of heavy development along the coasts, some marine mammals spend their lives in the middle of intense human activity.

Many "urban whales" are dolphins and porpoises. Taxonomically, dolphins and porpoises are whales—odontocetes, or toothed whales. While scientists still debate about the classification of species and subspecies, there are at least six species of porpoises, 26 species of oceanic dolphins, and five species of river dolphins.  Indo-Pacific humpbacked dolphins live amid the busy boat traffic in the shallow coastal waters of Hong Kong and Southeast Asia. Indus and Ganges River dolphins share waterways crowded by the growing human populations of India and Pakistan.

Whenever marine mammals live in urban environments, they are at considerable risk from chemical pollution, litter, and carelessly disposed fishing gear. Boats and their propellers are dangers, too. Dolphins often become entangled in fishing nets set close to the beach and are vulnerable to collisions with fast-moving pleasure and sport-fishing boats.

Wild dolphins are also placed at risk by well-intentioned humans who feed them. Many of us have seen these charismatic animals hand-fed at marine parks and zoos and in movies or on television. So when we see dolphins in the wild, we may feel an urge to feed them ourselves—which can be risky at best and deadly at worst. We must remember that wild animals are exactly that: wild.

At Monkey Mia, a beach on the west coast of Australia where dolphins have received human handouts for nearly 30 years, scientists have noticed that the calves of female dolphins regularly fed by people have a much higher death rate. And dolphins who learn to approach boats for food become more vulnerable to entanglement in fishing nets or even oblivious to the dangers that boats can pose during such close encounters.

It's exciting to have whales and other marine mammals as neighbors, but it's essential that their natural habitat remain as unpolluted and undisturbed as possible. As naturalist Henry David Thoreau noted, "in wildness is the preservation of the world."

Sharon Young is field director of The HSUS Marine Issues.

Helping Urban Marine Mammals

• When boating on the ocean, watch out for dolphins, porpoises, whales, manatees, and other animals. Operate at a reasonable speed.

• If your ocean- or bay-front property has a septic system, have it inspected periodically to ensure its proper operation. Improperly treated wastes that flow into coastal waters raise bacterial counts and may bring heavy metals and other contaminants into the ocean environment.

• Storm drains in urban or suburban streets may carry antifreeze, oil, and chemicals that wash away with the rain into the ocean. Check with your town to see whether storm drain water is treated before it is released.

• When boating or picnicking along the beach, dispose of your rubbish properly. A shiny gum wrapper may look like a slowly moving fish, and animals may swallow or get entangled in plastic bags that blow into the ocean by mistake. Trash that is eaten is trash that can kill.