The feeding strategy of Rainbow trout escaped from sea cages on the coast of Mazandaran

The present study was conducted to determine the exotic fish food strategy of rainbow trout escaped from cultivating cages located in the coast of Mazandaran.

A total of 90 specimens of this species were collected during the period from September 2017 to May 2018 from bony fish from west to central coast of Mazandaran. Samples were biomediated and the age was determined by scales.

The relative frequency of food items were Balanus glandula, Clupeonella cultriventris, Cerastoderma lamarcki, Neogobius fluviatilis, Atherina caspia, Chelon saliens, Chinavia hilaris, Taxiphyllum barbieri, Rutilus kutum, Cumacea, Syngnathus caspius and Gasterosreus aculeatus, respectively. The result showed that a wide range of food was more central than the west, the fullness index in the female was more than male and in age groups older than 2 and 3 is more than 1 (p>0.05). The fullness index, especially in the spring, increased significantly, the presence of B. glandula more than C. cultriventris, but its relative importance was less than C. cultriventris (p> 0.05).

This fish has a carnivorous behavior and uses a wide range of foods, so it is possible to compete with many species of Caspian Sea fish such as Salmo caspius. The effects of the adaptations and behavioral, physiological and ecological mechanisms, C. cultriventri and B. glandula were more important in fish feeding.