Age and Growth of Channel Catfish in the Lower Yellowstone River, Montana

Abstract

Channel catfish (Ictalurus punctatus) provide a significant rod and hoop net sport fishery in the Lower Yellowstone River, Montana. In order to obtain age and growth information for fish stock assessment, lengths, weights, and pectoral fin spines from 120 fish were used to backcalculate length-at-age and to fit von Bertalanffy growth curves. Fish ranged in age from 3 to 21 years old. A 300-mm long fish was age-4, a 450-mm fish was age-8, and a 700-mm fish age-14. Maximum observed age of this stock was higher than nearly all other stocks in the literature, and comparable to fish from the Tongue River, a nearby tributary. Growth rates of the stock were also slower than for most stocks. Based on a minimum quality size for anglers of 41 cm, a quality-sized Yellowstone River channel catfish was about age-7.