NAME: Brian Bridgewater
PROJECT TITLE: Benthic Trawling as a Supplement to Electrofishing on the Ohio River

View Brian's webpage here: http://webpages.marshall.edu/~bridgewater2

Over the past 40 years, the Ohio River Valley Water Sanitation Commission (ORSANCO) has been sampling the Ohio River main stem and its’ tributaries through various methods such as boat electrofishing and rotenone lock chamber surveys. The goal of these methods is to assess the river wide fish assemblage. A third method, benthic trawling, was started within the last two years in an effort to sample the benthic fish communities, which is being underrepresented by traditional methods. In 2006 and 2007, benthic trawling was conducted at 118 electrofishing zones to determine the utility of this method as a secondary collection technique to better characterize fish populations of the Ohio River. Two, one minute and two, two minute trawls were conducted at each 500 meter electrofishing transect at different depths and/or at different segments of the transect. An 8’ wide trawl was used for all sampling. In 2006, 240 trawls were conducted with a 72% (n=172) success rate. Trawling regularly captured species either rarely caught or never caught by conventional electrofishing yet yield was often lower than electrofishing in both numbers (2323 to 9157) and species (22 to 62). While average time spent trawling at each 500 meter transect was comparable to time spent electrofishing (~45 min), electrofishing returned many more individuals (9157 to 2323) and species (62 to 22). In 2007 data continued to support this pattern. These result support the use of trawling as a supplement to electrofishing for a more inclusive assessment of large river fisheries.