Feeding regime habits of kutum (Rutilus frisii Nordmann, 1840) fingerling in the estuary of Tajen River, Mazandaran

Document Type : scientific research article

Authors

1 Iranian fisheries science research organization

2 Iranian Fisheries Science Research

3 Iranian Fisheries Science Research Institute

4 Caspian Sea Ecology Research Center

5 Csaspian Sea Ecology Research Center

6 Caspian Sea Ecology Research Center, Iranian Fisheries Science Research Institute, Agricultural Research, Education and Extension Organization, Sari

Abstract

This research was carried out with the aim of determining the food indicators and dominant baits of Kutum, Rutilus friss fingerling in the form of a project to investigate the biological condition of Kutum fry released in the Tajen river estuary in 2022. Sampling was carried out using a beach seine net with a mesh size of 5 mm and a length of 70 m. The average length and weight of the fish caught were 2.5 cm and 1.25 grams, respectively. The identified food items included phytoplankton, zooplankton and zoobenthos groups. The Gastrosomatic index (GaSI) showed that on average it was 45.8±20.3, the minimum and maximum of which were 2.3 and 104.1, respectively and showed a significant difference (p<0.05). The condition factor (K) of R. frisii fingerling showed that its value varied from 0.12 to 3.3 and on average it was 0.9±0.53 and had a significant difference (p<0.05. The Vacuity index (VI) showed that the R. frisii fingerling in this stage of life have constant activity and did not have empty intestines.The study of the Important Species Index (ISI) in the digestive system of R. frisii fingerling showed that the Bacillariophyta was recognized as the most important food in the intestinal contents with 43%. The cluster analysis of consumed food baits based on Pearson's coefficient of homogeneity showed that Bacillariophyta and Cyanophyta the most similar was found (0.824). The frequency of occurrence index (FI) showed that the Bacillariophyta, Cyanophyta Rotifera and Arthropoda as a main food, and the Eaglenaphyta and Chlorophyta the secondary food and Cilliophora and zoobenthos rare food items was found.

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Journal of Utilization and Cultivation of Aquatics
Volume 14, Issue 1
April 2025
Pages 235-251

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