Age, length-weight relationships and diet composition of scaldfish Arnoglossus laterna (Walbaum, 1792) (Pisces: Bothidae) in Izmir Bay (Aegean Sea)

The age, length-weight relationship and diet composition of Arnoglossus laterna from the Izmir Bay were examined in specimens caught on a seasonal basis from January 2002 to March 2003. The ratio of male to female of 1081 scaldfish captured by trawl netting was 1:1.62 and their total lengths varied from 5.6-15.7 cm and total weights from 1.2-31.51 g. The length-weight relationships were estimated as W = 0.0035 L3.301; W = 0.0066 L3.043; W = 0.0073 L3.011 for females, for males and for all individuals, respectively. Based on the otolith readings, the age distribution of the samples varied from I to V years. The von Bertalanffy growth parameters were calculated to be L? = 16.87 cm, k = 0.236 year-1, t 0 = -0.887 year. Stomach contents of A. laterna were filled with preys of 5 major taxonomical groups: Polychaeta, Crustacea, Mollusca, Chaetognatha and Teleostei. A total of 11 prey groups were identified in the diets of scaldfish with most abundant crustaceans. According to a Bray-Curtis similarity index in relation to ages, two groups are formed based on index percentage of relative importance of food item; I-II age groups constituted the first similarity and III-IV-V the second one. © Medwell Journals, 2008