Seining Fun

Background Information:

A healthy environment supports a variety of native species. This is especially true for a wetland ecosystem. Like other living creatures, fish must meet certain basic needs for survival. Water, food and shelter are among the most important requirements:

• Water: Fish not only live in water, but they get oxygen from water. They breathe by taking water into their mouths and forcing it out through gill passages.

• Food: Fish must be able to find enough to eat at various life stages, whether they feed on microorganisms, smaller fish or larger prey.

• Shelter: Fish need a place to hide from predators and to reproduce. Some fish find shelter among submerged aquatic plants and shoreline vegetation, while others hide among rocks, soft sediments, or blend into clear, open waters.

Where can fish meet these needs? Fish are adapted to living in a variety of habitats. Some examples include the following: rivers, streams, inland lakes, Great Lakes, inland and coastal wetlands. These habitats can vary greatly in water quality, turbidity, speed of water flow, amount of vegetation, water temperature, and water composition. Fish are particularly sensitive to water temperature and oxygen content, which play a major role in determining which species can survive in a given water body.

Most inland wetlands such as Herb Kebbel are not deep enough for fish to survive the winter since the shallow waters freeze. However, there are smaller spots within this wetland area that are deep enough and do not freeze.

Human Impacts on Fish Habitat

Different species of fish require specific habitats, and loss or alteration of fish habitat can lead to population declines. Over the last century, many factors have altered water quality and fish habitat and subsequently affected native fish populations. Some examples include:

• Development in wetland areas: Wetland traditionally regarded as wastelands have been drained, filled in and developed into human uses such as farmland, housing, industry, etc.. These areas are critical during the early life stages of many fish species. Removal of shoreline vegetation and trees from riverbanks can decrease shade and increase water temperature. Lack of vegetation also increases erosion and sedimentation, which alters spawning areas. Dams and other obstacles can prevent fish from migrating upstream to reach critical spawning habitat.

• Invasive Species: Invasive species compete with native fish for food and habitat. Round goby and Eurasian ruffe are examples of fish that have displaced native species in some locations. Invasive species can also change habitat. By filtering microorganisms, zebra mussels reduce food for native species and increase water clarity, which stimulates growth of aquatic plants.

• Pollution: Industrial pollutants, urban and agricultural runoff, and sewage overflows are some of the sources of pollutants that continue to impair water quality and impact fish habitat.

All of these factors, with destruction of wetland habitat being the most common and severe, impact the entire ecosystem. Some inhabitants of a wetland habitat are particularly sensitive to pollution. Amphibians can be good indicators of the health of a wetland ecosystem. As a result they are known as good bioindicators. If many amphibian species are present it is indicative of a healthy wetland, if they are absent it suggests there might be some source of pollution.

The word "amphibian" is derived from the Greek words "amphi" and "bios" which means two lives and refers to the aquatic tadpole and the terrestrial adult stages of all salamanders, newts, frogs and toads. Amphibians all lay eggs and are characterized by their smooth, moist skin. Amphibians do not drink. They absorb water and much of the oxygen they need through their skin, although most use lungs as well. The permeable skin of an amphibian can also easily absorb pollutants and other toxins which can seriously harm, or even kill the animal.