Dead Fish, Dying Reefs

Although the feeding of fishes and other marine wildlife by recreational divers and snorkelers presents problems for marine wildlife and ecosystems, the practice has become increasingly common. Dive operators, for example, often use feeding to concentrate naturally dispersed wildlife in an effort to facilitate client viewing or to promote interaction between divers and marine life, while divers and snorkelers operating from private vessels often engage in feeding in misguided attempts to “help” or befriend wild animals. In either case, the practice negatively affects both natural resources and diver safety.

Wildlife management officials have long recognized the negative impact that feeding wild vertebrates has on both the fed animals and their ecosystems. Through classic conditioning, animals who are fed regularly learn to associate the presence of people with readily available food. This typically leads to a host of problems that have been observed across the spectrum of feeding-habituated species, including bears, deer, coyotes, alligators, and marine mammals. Sharks and bony fishes have been shown to be as adept as mammals in acquiring and retaining conditioned responses, and, as the popularity of fish feeding soars, the same problems that plague other fed vertebrates increasingly affect marine fishes as well.

The resulting problems are diverse. Often, the foods provided are not foods the fishes eat naturally or even foods they have the ability to process. A 2004 report on the Maldives states that usually “the food fed to these fish is radically different from their normal diet. As a result, some very large humphead wrasses died after being fed dozens of eggs, while many soldierfish choked to death after wolfing down chicken bones. Large basses have been seen to tear little sacks of food right out of the scuba diver’s hand, devouring both sack and contents.” Even a more “typical” diet, such as frozen fish, may prove lethal; for example, the deaths of feeding-habituated wild dolphins have been linked to bacteria associated with spoiled fish.

Feeding also disrupts or alters normal distribution, abundance, and behavior of marine fishes. The state of Hawaii concluded that fish feeding “changes the species composition in areas where the practice is done regularly, and fish become much more aggressive.” Some species form disorganized swarms that surround and aggressively approach, follow, and even nip at divers. Normally reclusive species like sharks, moray eels, and groupers may approach and follow divers, continuing their pursuit even as divers surface, a behavior which makes them easy targets for underwater hunters and poachers.

Environments are equally impacted. Benthic habitat damage (including loss of gorgonian corals) has been attributed to divers feeding fishes in Mediterranean marine parks, while in Australia, marine park managers say that “the unnatural addition of organic matter and nutrients to reef waters may have adverse environmental impacts, e.g., damage to coral caused by excessive growth of algae.” Hawaiian MPA managers reported that fish feeding both changed a fish community and degraded water quality. “The feedings caused a naturally balanced ecosystem to turn into something of a petting zoo . . . so much [so] that it is no longer considered a ‘normal’ reef ecosystem.”

The feeding of wildlife is expressly prohibited in all US and Canadian parks and wildlife refuges as well as in many local jurisdictions, yet the practice continues at many popular dive sites that are not under the umbrella of such legal safeguards. In the water, millions of divers and snorkelers worldwide interact with marine wildlife each year, and we cannot ignore their cumulative impact. Whether it’s a baited shark rodeo or handing dinner rolls to a sergeant major, more than 100 years of lessons learned the hard way tell us that feeding wildlife is a losing proposition -- for fed animals, for people who seek to observe wildlife, and for our natural ecosystems. Conscientious divers who care about marine ecosystems should not be party to feeding fish. If they are, the result will only be further destruction of natural marine habitats everywhere.

—The author, Dr. William Alevizon, is a marine biologist with the Wildlife Conservation Society.