Is von Bertalanffy model suitable for determining the growth of invasive Ponto-Caspian gobies?
Invasive Ponto-Caspian gobies, monkey goby Neogobius fluviatilis, round goby Neogobius melanostomus and bighead goby Ponticola kessleri have recently expanded their range and naturalized the Sava River basin in Croatia. Although their presence in Croatia has been noted and distribution and impact studied, age and growth have not yet been investigated. Using scales for age analysis, only first three age groups have been determined for the monkey goby (I, II, III) and first four age groups for the round and bighead goby (I, II, III, IV). The highest growth rate have been determined for the monkey goby and the lowest for the round goby. Significant difference of the back calculated mean length was observed for all three analysed species indicating the unreliability of the von Bertalanffy model. Instead, otolith annulus counting is recommended for a more precise age determination, as well as testing of other growth models.