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ABSTRACT
An investigation was made on food and feeding as well as some bio-indices like relative length of gut (RLG), Gastro-somatic index (GaSI) and Gonado-somatic index (GSI) in 275 samples of Labeo calbasu (total length 130 to 430 mm) occurring in wetlands of South 24 Parganas district of West Bengal for a period of nine months. The food items observed in gut contents constituted decayed organic matter, diatoms, mud and sand, algal matter, zooplankton and broken shells. The relative length of gut varied from 5.68 to 14.70 and it was significantly different between two size groups. The mean GaSI of male fish varied from 1.64 to 4.11 and that of female from 1.62 to 3.96. The mean GSI value ranged from 0.54 to 3.30 for male and 0.56 to 9.65 for female and it was significantly different in different months and sex.
Keywords: Labeo calbasu, Food and feeding habits, Relative length of gut, Gastro-somatic index, Gonado-somatic index, Wetlands, West Bengal.
INTRODUCTION
Studies on food and feeding habits and other bio-indices of fishes are considered very important in aspects of fishery management and conservation. Knowledge on food and feeding habits of fish is needed to have better understanding on growth, condition, maturity, migration etc. Food and feeding habits of the fishes varies from habitat to habitat and food items are also different with respect to time and space, and in response to food requirement at different stages of life (De Silva, 1973). Food and feeding habits of various fish usually depends on the availability of foods in surrounding environments and their feeding nature. The time and extent of changes in food and feeding habits varies from species to species and often with changes in the life style or habitat (Blaber, 2000).
Food and feeding habit and other bio-indices of L. calbasu were studied earlier by a number of researchers (Alikunhi 1952, 1957; Kumar & Siddiqui 1989; Singh and Singh 2000; Dasgupta 2001 and 2004; Mishra and Saksena, 2012; Kabia and Quddus, 2013 and Laghari, 2015). Studies on food and feeding habit of fish are quite important to have good understanding on biology and management of fishes (Chakraborty et al., 2016). There is need of regular biomonitoring on biology and foraging of fish due to climate...