When people think of water critters, they usually imagine fish. Not many people would talk about mayflies, crayfish, or fishing spiders. But without these animals, there would be no fish. Fish depend on these spineless critters for food They are called invertebrates. These small, shy animals live in lakes, ponds, rivers, and streams across Pennsylvania. They belong to a larger group of animals called arthropods. This group of animals includes crustaceans, spiders, mites, and insects. They are also the largest group of animals on earth.
Arthropods do not have a backbone, like a fish, or a person. They have a hard outer shell called an exoskeleton. As they grow, they have to shed their shells many times. In the water, animals such as crayfish, stoneflies, mosquitoes, and water striders are very important. Many of them eat other small animals. Others eat small plants. Some even chew up the fallen leaves and eat dead animals. But almost all of them are eaten by the many bluegills, bass, and trout we love to catch!
Many of these critters live under water their entire lives. A crayfish may choose one rock and never leave it except to search for food or drive away another crayfish. Some of the insects, however, may live one or two years under the water and then grow wings and fly away. Did you know that dragonflies hatch out of the water? After they hatch, they fly around the same area where they were born. They eat mosquitoes and small flies. Some dragonflies even migrate each year!
So the next time you go fishing, take a minute to look in the water up close. Turn over a rock, stick, or a few leaves. You'll be surprised by what you see crawling, swimming, and wiggling under the surface.
September/October 1998 Angler & Boater
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