A survey on some feeding and biological characteristics of Sand Melt (Atherina boyeri caspia) in the Caspian Sea Coasts, Tonekabon County, Iran

In this study, 104 specimens of sand melt caught in the Tonekabon County coasts in summer and autumn seasons (2015). The samples were fixed in 10% formalin and transferred to the laboratory for more studies. The length and weight average of A. boyeri caspia were obtained 10.33 cm and 6.76 g in summer and 10.30 cm and 7.46 g, respectively. The length-weight relationship of this species in summer and autumn is  and , respectively. Moreover, the results indicated a higher condition factor in autumn than summer. Pauly method was used to survey the growth pattern in this species. Based on result, the Sand Melt in the Tonekabon coast had a negative allometric growth in both summer and autumn, indicating a lower growth rate of weight than length in this species. In addition, the empty stomach index (CV) showed a relative overeating. The survey of the relative length of gut indicated carnivorous diet of A. boyeri caspia. Also, the study of fullness index showed that this species is in a good nutritional condition. The Food Preference Index showed that this species doesn’t have the main food, and only the Gammaridae and Bosminidae were their sub food.