Age, Reproduction, Growth, Condition and Diet of the Introduced Yellow Bass, \u3ci\u3eMorone mississippiensis\u3c/i\u3e, in Barren River Lake, Kentucky

Introduction of fish species to North American drainages has occurred for over 100 years. Introduced fish species have been documented to have adverse effects on both the environment and native species of the drainage into which they have been introduced. To better understand the effects that introduced species may have on a particular drainage, it is essential to understand aspects of the introduced species’ life history. The objectives of the current study is to quantify the age, reproduction, growth, condition and diet of the yellow bass, Morone mississippiensis, in Barren River Lake, Kentucky. Monthly collections from three areas on Barren River Lake were made via a boat-mounted electrofisher from March 2008 to March 2009. Fish age was estimated by examining the sagittal otoliths of each individual. Reproductive condition was assessed using the mean gonadosomatic index (GSI) of all sexually mature individuals by month. Yearly growth rates were estimated by computing the mean length at age for each age class and subsequent calculation of the von Bertalanffy growth function (VBGF). To estimate the condition of yellow bass as it changed throughout the sample period, relative weight of each individual was calculated and the mean monthly relative weight was calculated. To examine the diet of yellow bass, diet items were identified to the lowest practical taxonomic level. Then, dry weight of each diet item was estimated and pooled by season to assess the season changes in the diet of yellow bass. Individuals of age group 3 were the most frequent. Mean GSI was significantly higher in March, April and May of 2008. Calculation of the VBGF yielded 254.7 mm as the maximum attainable mean total length of yellow bass in Barren River Lake. VBGF predicted mean total lengths of age classes 0-8 were as follows: 21.7 mm, 64.4 mm, 99.2 mm, 127.7 mm, 151.0 mm, 170.0 mm, 185.5 mm, 198.2 mm, and 208.5 mm. Relative weight was highest in summer. The diet of adult and sub-adult yellow bass relied heavily on chironomid larvae and pupae throughout the year, although diet item consumption was very low in winter. Young-of-year gizzard shad (Dorosoma cepedianum), however, became the most important adult diet item in the spring and summer. To better understand the impacts that the introduced yellow bass has on the ecosystem of Barren Rive Lake, a multi-year study including an estimation of relative abundance is recommended