OUTDOOR CORNER: CAVEFISH'S DECLINE IN NUMBERS IS INDICATOR OF POLLUTED WATERS

Fish lives in the darkness of Missouri's caves.

Have you wondered if there are fish in the state of Missouri that live in water that is underground? Are you a person who likes to see the unseen, or do you believe that fish that are small only have one purpose and that's to feed larger fish? There are numerous small aquatic species that play a principal role in the aquatic environment. One of these would have to be the cavefish.

Most cavefish survive in total darkness. Since these special fish occupy a unique habitat, they are rarely ever encountered. There are six species of cavefish in the eastern portion of the United States. Three of these species are found in Missouri. Cavefish, are not usually seen because most potential habitats are not directly accessible. These fish live in aquifers, wells, springs and caves.

All three of the species of cavefish in Missouri are small in size with the largest, the southern cavefish, growing to 3.4 inches. The cavefish's color ranges from white to light brown and their scales are so small that their bodies appear to be skinless or naked. Cavefish are one of two groups of fish that has their anus located underneath their throat.

The southern and ozark cavefish don't have eyes; however, the spring cavefish has very small eyes that have very little function. Cavefish have external organs that occur liberally on the head, body, and fins of the fish. These organs compensate well for the absence of sight, allowing the fish to carry on its normal functions in total darkness.

Cavefish feed mainly on small, salamanders, crayfish, other invertebrates, and when food is extremely limited they will eat young of their own species. All of these organisms are dependent on the organic matter produced by bat guano, animal scats, leaves and wood.

The Ozark cavefish reaches maturity around four years of age, and they have a life expectancy of seven to 10 years. The females will produce 20 to 25 eggs per spawn with about 20 percent of the population breeding each year. A small breeding percentage of the population may be an adaptation to the low carrying capacity of the habitat due to habitat destruction. Little is known about the breeding habits of the southern and spring cavefish due to their secretive habits.

Populations of cavefish are declining, probably due to human land practices. Dysfunctional septic systems, improper disposal of chemicals and petroleum products, uncontrolled animal waste runoff or leaking sewage lagoons and poor soil conservation practices are just a few examples of how we affect the habitat of cavefish.

Most people fail to recognize how all organisms are connected. For example, a lot of people pour toxic substances in sinks and sewers and as long as the water that they drink is okay, everything is fine.

But what happens when the water tastes bad, looks bad, and is far from pure. That will be the day when everyone is concerned. When will we realize that if these animals are dying it is an indicator that the water isn't as pure as it should be and soon it probably won't be fit for human consumption?

After all, the same water that we drink in some cases comes from the same place these cavefish live. If there weren't better ways to accomplish the needs of humans, I could understand why some individuals don't care; however, there are other alternatives that don't threaten the environment and accomplish the needs of the people. Cavefish are very important indicators of a healthy environment and they deserve our protection.

Christopher Kennedy is a fisheries management specialist for the Missouri Department of Conservation.