Age and growth, reproduction and diet of a sublittoral population of the rock goby Gobius paganellus (Teleostei, Gobiidae)

Basic biological information for a sublittoral population of the rock goby Gobius paganellus Linnaeus, 1758 is presented based on a 2-year study involving 1680 specimens. The length-weight relationship was given by TW = 0.0089 * TL3.163 (where TW = total weight in g: TL = total length in mm. Age at length data were inferred by modal analysis of the monthly length-frequency distributions. The parameters of the fitted Von Bertalanffy growth equation (with seasonal component, birth date on the 1st of January) were L-infinity = 13.8 cm, K = 0.73 yr(-1) t(o) = -0.22 yr, C = 0.95: W = 0.07. This growth rate is much higher than that described for northern Europe populations (where K is about 0.3 yr(-1)) and is probably associated with a shorter life span. Macroscopic examination of the gonads, and analysis of the monthly values of the gonadosomatic index, indicated that reproduction occurs in winter and early spring, with a maximum in February and March, when water temperatures are lowest. Individuals become sexually mature around 6-7 cm TL, a size that can be reached in less than 1 year. By contrast, individuals of this goby in the British Isles mature in their second or third year. Stomach contents were mainly small benthic invertebrates, predominantly crustaceans.