Reproductive Characteristics Differ in Two Invasive Populations of Blue Catfish

Abstract

AbstractThe management of invasive Blue Catfish Ictalurus furcatus in Chesapeake Bay tributaries is hindered by the lack of information on its reproductive biology, which is a key component of population models used to forecast abundance. We quantified and compared the reproductive traits of female Blue Catfish from two populations from the tidal reaches of the James and York River subestuaries during 2015–2017. In these systems, Blue Catfish matured between the ages of 6 and 10 years and spawned between May and July, with larger fish spawning earlier in the season. During spawning events, Blue Catfish produced 2,613–68,356 eggs, with larger and older fish producing more eggs. Fish in the more densely populated James River matured at a marginally older age but a significantly smaller size than fish in the York River, but James River fish allocated more energy to reproduction. Fish in the James River also had greater mean values of the gonadosomatic index, relative fecundity, egg organic content, and proportion of organic content in the eggs. Relative fecundity of Blue Catfish decreased with fish size, contrary to observations in most other fishes. Based on the observed variability in reproductive traits and the size dependence of relative fecundity, we recommend incorporation of population‐specific reproductive rates into stock assessment models for invasive Blue Catfish.