2007 Participants
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Derek McKinney
Working with Dr. Mike Little

The Use of Substrate Mapping Techniques to Predict Benthic Fish Populations.

            The purpose of my project will to be able to show and predict populations of benthic (bottom dwelling non-game) fish populations by using substrate maps of the Ohio River.  Historically fish collection was done on the Ohio River by ORSANCO (Ohio River Valley Water Sanitation Commission) with electro-fishing at nighttime.  Our sampling technique is going to be with a Modified Missouri Trawl during daylight hours.  The electro-fishing is only effective in less than ten feet of water and under represents the benthic fish populations, being most of the individuals are located in more than ten feet of water.  If the fish are hit with an electric current they normally won’t make it to the surface since they are trapped under the rock in which they are hiding under. The trawling method solves these problems by being able to go into deeper water and actually turning over the rocks and catching what is hiding under them.
             Trawling will be conducted at a total of 20 sites (500 meter long transects) distributed evenly throughout four Ohio River navigational pools. The four pools selected for this project are: Robert C. Byrd, Montgomery, Greenup Pool, and Cannelton Pool. 10 sites will be chosen as best habitat and 10 sites will be random habitats. Coordinates and an approximate river mile and bank designation for the sites will be conducted using GIS Software. Four snag-free downstream bow trawls will be conducted at each of the 20 sites. Trawl locations will be selected based on habitat type. Selectivity of habitat will be completed prior to sampling each pool. This will be done using a variety of methods. US Army Corps of Engineer side scan sonar data, along with ORSANCO substrate data will be used to predict substrate and habitat locations within the river. Each trawl should last for about 1 minute (approximately 100 meters). Exact trawling locations can be shifted in order to avoid snags or other obstructions. Shifts should, however, be minimal and trawls should take place as near to the given points as possible. Coordinates should be recorded at the start and end of each trawl. Other data that should be recorded for each trawl should include, but not be limited to: (1) duration, (2) time of day of start of trawl, (3) average depth of trawl segment, (4) approximate distance from shore, (5) and approximate boat speed. A temperature profile of the entire sampling zone shall also be reported.