Seining

The Aquatic Assessment crew frequently uses seines, much like the one pictured below, to sample fish communities. The seines used by the Aquatic Assessment crew have both a “lead line” and a “float line”. The lead line has several lead weights attached to it and keeps the seine close to the bottom to prevent fish escape. The float line has several Styrofoam floats attached to it to keep it floating on the top of the water column. Two people then manually pull the seine through the area to be sampled. Our seines have a bag sewn in the middle of the seine. When the seine is being pulled through the water, the bag deploys a couple of feet behind the rest of the net. This is where the fish collect. Seines are typically used in situations where elecrofishing is either not possible or not practical. Some instances of this would be sampling residual pools in a stream that has almost dried up, sampling beaver ponds where the fish could easily escape the electrical field produced by electrofishing gear, and anyplace where a biologist feels electrofishing was not effective at sampling the entire fish community. Seines typically work best when fish cannot escape around, below, or above the seine. Therefore, when choosing a seine for sampling, factors to consider include water depth, channel width, and amount of debris in the water.