Largemouth Bass
Electrofishing Results, 2002

2002 Spring Electrofishing Bass Survey Results

2002 electrofishing results released (9/12/02)

Results of electrofishing surveys collected this past spring by Oklahoma Department of Wildlife Conservation (ODWC) fisheries crews indicate that catch rates of bass were lower in some lakes compared to 2001. In most cases when compared to recent historical averages these differences are not dramatic.

"Our biologists have collected this data for many years because we need to evaluate how bass populations change over time," said Kim Erickson, ODWC fisheries chief. "One or two year's results don't make a trend, so we try to look at the bigger picture over a longer time frame."

ODWC biologists have used the numbers of fish collected per hour of electrofishing in the spring as an index for managing bass populations since the mid-1970s. Over the years, changes have been made in sampling equipment and procedures, but the results of sampling over the last 10 years are relatively comparable on a lake-by-lake basis. Lakes are classified as "quality" bass lakes if they produce at least 40 bass per hour of electrofishing, and of those, at least 10 must be 14-inches or longer. In comparison, "high quality" bass lakes must produce at least 60 bass per hour, of which at least 15 must be 14-inches or longer.

Angler reports and bass tournament results received over the last two years have been discouraging both to fishermen and ODWC biologists.

"We've been addressing complaints about poor bass fishing since last summer," Erickson said. "We don't disagree that fishing is off at some lakes, but when we look at this year's electrofishing results we don't agree, as one angler suggested, the sky is falling."

For example, 2002 bass catch rates (all sizes combined) from lakes Grand (114 bass per hour), Hudson (117) and Ft. Gibson (117) were lower than in 2001, however the 2001 spring electrofishing results were the highest recorded catch rates in history on those lakes. Comparing this year's catch rates on bass greater than 14-inches to the average catch of the last five surveys show numbers were only slightly down or about the same at Ft. Gibson and Grand respectively, but were higher at Hudson.

Lakes Eufaula and Tenkiller seem to show the most evident change in bass electrofishing catch rates. Lakewide bass catch at Eufaula in 2002 fell below the five-year average (48 bass per hour, all sizes) to 34 bass per hour and to 11 per hour for bass 14-inches or longer. However, bass numbers in the North Canadian arm of the lake showed the highest catch overall with 56 bass per hour (all sizes) and 23 per hour 14-inches or longer. Lake Tenkiller, the only lake in Oklahoma to have had a confirmed Largemouth Bass Virus (LMBV) fish kill in 2000, had its second highest recorded bass catch rate in 2001, but its lowest overall bass electrofishing catch rate since 1990 in 2002. Earlier electrofishing surveys found that the 1998 year-class of bass was one of the weakest ever recorded in the lake which could explain some of today's slump in fishing success.

Lake Konawa, also found to have LMBV in the bass population, but never to have had a disease-caused fish kill, once again had the highest catch rate of the state's larger lakes (209 bass per hour, all sizes). Of the smaller lakes (under 1000 acres), Shidler Lake in north central Oklahoma had the highest catch with 134 bass per hour.

Variations in electrofishing catch rates can result from lake conditions at the time of sampling or from changes in reproduction, recruitment, growth and mortality caused by habitat alteration, environmental impacts, food fish production, disease or angling pressure. All fish collected by biologists through electrofishing are weighed, measured and released unharmed.

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Editors Note: For complete electrofishing results, go to www.wildlifedepartment.com/electrofishing2002.htm

2002 Spring Electrofishing Bass Survey Results

* Denotes Lakes Less Than 1000 Acres