Age, Growth, and Catch Analysis of the Commercially Exploited Paddlefish Population in Kentucky Lake, Kentucky-Tennessee

Abstract

Paddlefish Polyodon spathula from the 1985-1986 commercial harvest from Kentucky Lake, Kentucky-Tennessee, were weighed and their lengths from eye to fork of the tail were measured. During 52 observed trips, commercial fishermen harvested 702 paddlefish (4,002 kg) with 788 gill-net-nights of effort. However, the harvest was a disappointment to the fishermen because catch rates were low, and only 15 gravid females were included in the observed catch. The paddlefish that were aged from dentary bones (N = 362) were 2-16 years old. The age-length equation was a log10 transformation of a linear relationship, and the weight-length equation was a log10 transformation of an algebraic relationship. There were no significant differences in backcalculated growth between sexes. Growth was slower than reported for most other populations. The sex ratio was 1:1, and the youngest sexually mature fish were 6 and 8 years old for males and females, respectively. The age of recruitment and annual mortality were 8 years and 61 % for males and 9 years and 60% for females. Overall recruitment age was 9 years, and annual mortality was 69%. The mean length and weight of paddlefish in the commercial catch was 691 mm and 5.7 kg, the mean commercial catch was 57.1 kg and 13.5 fish per night, and mean catch per unit effort (CPUE) was 3.77 kg/91.4-m net per night. Mean size offish, catch rate, and CPUE were highest during the spawning run. A gill-net mesh size of 127 mm was most popular and caught larger fish. The Kentucky Lake paddlefish population shows several signs of overexploitation: high mortality for several years, a comparatively young population, and a low number of spawners. Therefore, we recommend the creation of a spawning refuge, implementation of a maximum gill-net mesh size, and an increase in commercial fishing license fees for paddlefish management.