1998 Fourth Quarter Report

Largemouth Bass Habitat Use in the Belleville Pool of the Ohio River

Task 2: Juvenile largemouth bass habitat use

Elizabeth Hoffman and Kyle Hartman
West Virginia University
January 19, 1999

Objectives

1. Determine young of year (YOY) and juvenile largemouth bass habitat selection within the Belleville Pool of the Ohio River.
2. Determine seasonal water quality differences between various habitat types (mainstem river, embayments, tributaries), and correlate water quality data with YOY and juvenile habitat preferences.

Methods
A habitat use assessment for YOY and juvenile largemouth bass in the Belleville Pool of the Ohio River was initiated on August 4, 1998. Sites for surveys were chosen based on the three types of habitat; mainstem river, embayment, and tributary. Effort was made to sample evenly between the various habitat types whenever possible. The information presented in this report is from data collected between August 4 and December 18, 1998. Fish were collected by direct current (DC) electrofishing. Each survey was conducted at a constant speed for 15 minutes at the selected sites.

Surveys were conducted in all of the habitat types (mainstem river, embayment, and tributary) several times each month. At the end of each electrofishing run, all species were recorded and total lengths were taken before their release. Occasionally, very large fish were not netted due to lack of room in the collection tank. When a juvenile largemouth bass was netted, a marker was thrown to the approximate location of capture and electrofishing was continued until the 15 minute survey was complete. After lengths were taken on the other fish species captured, we returned to the site of the bass's capture to record water temperature, dissolved oxygen, turbidity, depth, conductivity, salinity, nearest feature, and visible habitat. Initially, we attempted to record current velocity, but the instrument was not sensitive enough to detect the low levels of flow common in the Belleville Pool.

Total length and wet weight were recorded for each bass prior to tag implantation. Numbered Floy tags were implanted into the visceral cavity of fish exceeding 6 inches total length. Fish were anesthetized prior to tag implantation using a clove oil solution. A vertical incision just large enough to allow entrance of the tag was made anterior and dorsal to the anal vent. Fish were recovered in an aerated tank until equilibrium was gained. After recovery, fish were released near the site of capture. During the first two and a half months of the collection season, prior to arrival of the Floy tags, fish captured were fin clipped (left pectoral).

Early in the collection season surveys were conducted during both day and night. Initial electrofishing results showed little or no difference in catch between night and day. Thereafter, surveys were conducted mainly during daylight hours. After several attempts, seining surveys were terminated due to shoreline composition. We were not able to find any littoral zones with sediment firm enough to walk on while seining.

Progress to Date
A total of 18 field days and 17.75 electrofishing hours were spent attempting to capture juvenile and YOY bass in the Belleville Pool for habitat use assessment between August 4 and December 18, 1998. Adult largemouth bass were captured along with the juveniles during electrofishing runs, but were not included in the following totals. To date, 16 juvenile bass have been tagged and released with no initial mortalities. All fish were captured by DC electrofishing. Throughout the month of August no largemouth bass were captured during 180 minutes of actual electrofishing time (3 hours). Species netted during electrofishing runs were predominantly flathead and channel catfish. In September, two juvenile bass were captured and fin clipped during 255 minutes of electrofishing time (4.25 hours). Of the two juveniles collected, one was captured in an embayment and one in a tributary.

The most common species captured were flathead catfish and freshwater drum. During sampling in October 16 juvenile largemouth bass were captured. Ten juveniles were fin-clipped and 6 were Floy tagged. The majority of bass were captured in tributaries. Two juvenile largemouth bass were caught in an embayment. We spent a total of 210 minutes (3.5 hours) electrofishing in October, and the most prevalent species captured were freshwater drum and bluegill. Nine largemouth bass were captured in November and eight juveniles were tagged. One juvenile died after capture, and was not tagged. This fish appeared to have a fungal infection on its snout and likely was in a weakened condition, which caused it to die from handling stress. Of the juveniles tagged during November, six came from embayments (five from one location) and the other three from tributaries during a total of 210 minutes (3.5 hours) of electrofishing time. Common species captured included bluegill, smallmouth buffalo, and freshwater drum.

In December four largemouth bass were captured and the two juveniles were Floy tagged. The juveniles were captured in one embayment. Electrofishing effort totaled 210 minutes (3.5 hours). The most prevalent species captured during December were smallmouth buffalo, golden redhorse, and bluegill. Water quality data will be analyzed for correlation to juvenile and YOY habitat preferences. All data from 1998 have been entered and will be analyzed statistically by early 1999.

Special Considerations
Extremely low catch rates to date account for the small amount of data collected. Toward the end of 1998, capture of all fish species by electrofishing appeared to decline considerably. This is probably due to movement of the fish deeper into the main channel. As electrofishing is limited to the shallows and shoreline, bottom trawls may be initiated early in 1999. Although effort was made to sample evenly among the various habitat types, weather and water conditions prevented sampling in the main channel on occasion. There does not appear to be much variation in the water quality variables we have been measuring between the survey sites. Sediment samples may be collected at each capture site and analyzed for composition, if suitable equipment can be located. We are also going to purchase a new low velocity flow meter for future data collection efforts. If juvenile bass catch rates remain extremely low other issues that may be studied include tournament-related mortalities and creel surveys in the Belleville pool.