Dite of Wels, Silurus glanis of Amirkelayeh Wetland of Lahijan

A survey on dite of Silurus glanis of Amirkelayeh wetland was investigated seasonally during of 2001-2. Fishes were caught using different gears such as gillnet, common haul sciene, cast net, dipnet and electroshoker. Caught fishes were biometry, age was determinated and then necropsy. Results on diet survey of 132 Silurus glanis showed that this fish was fed on 16 food types. Includings Tinca tinca and Amphipoda each with frequency of 36.3% and Blicca bjoerkna, Silurus glanis, Pungitius Platygaster, Perca fluviatilis, Rat, Bird, Water buge, Pleochoptera each with frequency of 2.2% show the highest and lowest values respectively. Also Proterorhinus marmoratus, Odonata, Carassius auratus gibelio, Frog, Cobitis taenia and water beetle had meadium frequency. Amirkelayeh wetland Silurus glanis were in age groups of 1+- 7+ (No any specieman was not at 6+ age group were catch), had average Total length of 50.6 cm (32.5 – 73 cm), average weight of 944.2 gr (200 - 3000 gr), average relative length gut of 0/71 (0/4 – 1/12), average Index of flulness of 292.5 (58.8 – 707.6) and average fullton’s condition factor of 670 (399.9 – 936.6). Meanwhile, vacuity index was zero. It is noteworthy that most of food types were in the stomach of Silurus glanis and intestine had digested foods or food wastes, that express the palatability of these foods and ability of fish selection according to prey size and use of vision and olfactory. According to results of present study, Silurus glanis is a carnivores, piscivores and shows cannibalistic deheviour. It’s diet change according to season, age and sex which is related to diversity of food types, but there is no significant differences between these values and relative length gut, Index of fullness and fullton’s condition factor.