Length-weight relationships (LWRs) of fishes provide important information for many studies in a given geographic region, such as comparing the condition, fatness, estimation of weight-at-age from total reported catch weight, and length-frequency distributions (Tesch, 1968), as well as for interregional life-history comparisons (Petrakis and Stergiou, 1995). The relationships may change temporarily and/or spatially, and for this reason should be regularly updated (Ismen et al., 2007). The northern Aegean Sea is an important region for fisheries; fish stocks are heavily exploited by artisanal and industrial fishermen. Although length-weight relationships of many fish species have already been determined from the northern Aegean Sea (Koutrakis and Tsikliras, 2003;

The stomach contents of juvenile sharpsnout seabream, Diplodus puntazzo, and juvenile two-banded seabream, Diplodus vulgaris, were investigated in order to determine feeding habits and diet overlap among them. Fish were collected from October 2008 to August 2009 using a beach seine net from the Çanakkale coasts of Turkey. A total of 129 juvenile D. puntazzo (ranging from 13 mm to 77 mm total length) and 951 D. vulgaris (ranging from 15 mm to 97 mm total length) were collected during the sampling periods in the study area. The stomach content analyses showed that the diet of both species mainly comprised copepods and amphipods. In addition, algae were found in the stomach contents. No significant differences were found between the feeding habits of juvenile D. vulgaris and D. puntazzo (ANOSIM; global R statistic = -0.0158; P > 0.05). An important overlap in the diet calculated using the Schoener index was recorded as 0.75 for D. puntazzo and D. vulgaris. Consequently, there was a significant diet overlap and competition for available resources among the feeding habits of D. vulgaris and D. puntazzo in juvenile periods.

The relationships between fish total length and otolith measurements (OL, OW and OR) were described by means of allometric power equation for 36 fish species from Gokceada Island, Turkey. Regressions were also estimated at genus level. A total of 14364 specimens were collected monthly using beach seine (0-2 m) and beam trawl (5-20 m) from June 2013 to June 2014. Generally, the otolith length showed the highest correlation for predicting fish total length. This paper represents the first relationships between otolith morphometrics and fish total length for 12 species. These relationships can be useful for researchers who examining stomach contents of piscivorous predators.

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