Releasing Bullfrogs

I was dismayed to read that the Department of Water and Power’s head operator at Big Tujunga Dam, Bill Gilbert, has been raising bullfrogs and releasing them into the wild. The release of animals into natural areas is virtually always a bad ecological practice. This is especially true when the released animals would never have occurred there naturally. The bullfrog (Rana catesbeiana), is not a native species (it was introduced to California from the eastern United States about 100 years ago) and scientific evidence indicates that it has contributed to the decimation of native amphibian populations. Native frogs, such as the foothill yellow-legged frog (Rana boylei) and the California red-legged frog (Rana aurora), are extremely vulnerable to competition for resources (food, safe sites, etc.) by bullfrogs. Today, bullfrogs are abundant in wet places in the Big Tujunga area and yellow-legged frogs and red-legged frogs can no longer be found.

Native and alien species are not ecologically interchangeable, despite the fact that they are sometimes capable of occupying the same habitat. The displacement of native frogs by alien bullfrogs has surely had far-reaching and destabilizing ecological consequences. I am sure that Gilbert means well when he releases his bullfrogs into nature. Unfortunately, he is only helping to perpetuate a significant ecological problem.

PAULA M. SCHIFFMAN

Schiffman is an associate professor of biology at Cal State Northridge

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* Bullfrogs are extremely destructive. They prey upon creatures that are native to our local ecosystem, some of which are endangered.

When people release creatures into an environment where nature did not put them, consequences can be and often are devastating, causing great harm to the plants and animals that are part of the local ecosystem. Disillusioned pet owners, recipients of gift animals, scientists and others must keep this in mind.

MURIEL S. KOTIN

Sherman Oaks

Kotin is conservation chair of the San Fernando Valley Audubon Society.