|
|
Fish Screens and Fish Ladders 1) Fish Ladders, allow fish to enter a new area. The First question to ask prior to constructing a fish ladder, is "Should a fish ladder be constructed here?". While fish ladders can be an important tool to improve fish spawning and migration. Put in the wrong place they may actually harm native fish species. If there are natural or manmade barriers to fish passage, such barriers can help protect native species upstream from, competition, interbreeding, and disease brought by introduced species. Also fish ladders generally should not be placed on tributaries that go dry, (thus trapping fish upstream without water). If a fish ladder is to be constructed there are a variety of designs appropriate for a number of conditions, fish ladders generally are designed for the specific condition. A properly designed fish ladder will encourage fish to enter it instead of trying to get over the dam or barrier. In some cases fish will use the ladder more often than the main channel of the stream, when the diversion is not in use. 2) Fish Screens, block fish from entering an area. Like fish ladders fish screens are a risk rewards question. Diversion ditches often provide suitable habitat for fish. If a ditch is screened it blocks the fish from that habitat. So the question has to be asked is the ditch more of a threat, or a help to fish? If fish screens are built there are a huge variety of designs to choose from. Ranging from screens that fit on the bottom of pumps to huge rotating drums that block fish from an entire area. Fish screen are a relatively expensive item to construct. However, there are a number of government programs that assist in funding. If you are interested in these programs please contact us. |