The use of otolith length and weight measurements in age estimations of three Gobiidae species (Deltentosteus quadrimaculatus, Gobius niger, and Lesueurigobius friesii)


Abstract: Age estimations were made using otolith length and weight measurements from 3 goby species in the central Aegean Sea: the four-spotted goby (Deltentosteus quadrimaculatus Valenciennes, 1837), the black goby (Gobius niger Linnaeus, 1758), and Fries's goby (Lesueurigobius friesii Malm, 1874). A total of 266 individual four-spotted gobies, 283 black gobies, and 124 Fries's gobies provided otolith samples for analysis. The relationships between fish age and otolith length and fish age and otolith weight were determined, as were the relationships between total length and otolith length and total length and otolith weight. Results indicated that the relationship between fish age and otolith weight was the most suitable for estimating the age of the studied species. The relationships were estimated at t = 0.338W - 0.199 for the four-spotted goby, t = 0.147W - 0.085 for the black goby, and t = 0.400W - 0.619 for Fries's goby. The present paper also provides drawings of the species' otoliths to aid in the identification of the species. This research provides information that can be applied not only for age estimation but also for prey identification and estimation of the size of prey ingested by piscivorous predators.

Keywords: Alternative age estimation method, four-spotted goby, black goby, Fries's goby

Full Text: PDF