2017 Volume 83 Issue 1 Pages 18-24
Age and growth rates of the invasive exotic catfish Ictalurus punctatus were assessed by examination of otolith sections of 937 specimens (3.8-57.2 cm in standard length, SL) collected in Lake Kitaura, Ibaraki Prefecture, Japan. An opaque zone on the otolith margin, formed once a year from May to June, coincided with the peak spawning season. Von Bertalanffy growth equations differed significantly between sexes, being SLt=63.5{1−exp[−0.120(t+0.416)]} for males and SLt=56.5{1−exp[−0.134(t+0.437)]} for females [SLt is SL (cm) at t (year)]. The estimated maximum ages for males and females were 14 and 13 years, respectively. An age-length key for converting length frequencies into age frequencies was established, and is a useful tool for assessing the population status of the species and the development of effective management strategies.