Reproductive Characteristics Differ in Two Invasive Populations of Blue Catfish

Abstract

The management of invasive Blue CatfishIctalurus furcatusin Chesapeake Bay tributaries is hindered by the lackof information on its reproductive biology, which is a key component of population models used to forecast abun-dance. We quantified and compared the reproductive traits of female Blue Catfish from two populations from the tidalreaches of the James and York River subestuaries during 2015–2017. In these systems, Blue Catfish matured betweenthe ages of 6 and 10 years and spawned between May and July, with largerfish spawning earlier in the season. Dur-ing spawning events, Blue Catfish produced 2,613–68,356 eggs, with larger and olderfish producing more eggs. Fishin the more densely populated James River matured at a marginally older age but a significantly smaller size thanfishin the York River, but James Riverfish allocated more energy to reproduction. Fish in the James River also hadgreater mean values of the gonadosomatic index, relative fecundity, egg organic content, and proportion of organiccontent in the eggs. Relative fecundity of Blue Catfish decreased withfish size, contrary to observations in most otherfishes. Based on the observed variability in reproductive traits and the size dependence of relative fecundity, we recom-mend incorporation of population-specific reproductive rates into stock assessment models for invasive Blue Catfish

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