Preferences of fishes to different types of Katha materials used in sanctuaries in three rivers of Netrokona.

Abstract

Use of different fish-friendly ‘katha’ materials in fish sanctuary is a new concept in Bangladesh. Two kilometers area of each of the three rivers namely the Updakhali, the Kalihar and the Kangsha in Netrokona district were used to set up four sanctuaries in order to evaluate the preference of fishes to katha materials. Three types of katha materials viz. tree roots, bamboo roots and tree branches (traditional) and one blank spot (without katha materials) as control were tested. The study was conducted for two years from November 2003 to March 2005 and fish were harvested three times per year during December, February and March. A total of 43 species of fish were recorded. In the second year, the total number of fish increased 6.40, 8.42 and 8.39 folds than that of the first year in the tree root, bamboo root and traditional katha, respectively. The maximum species composition (40) was found in the traditional katha and the minimum (30) in the bamboo root katha. Out of 43 species, 11 species were found to prefer all the three types of katha materials and aggregated in large numbers. Among the mostly available 11 species, Titari, Psilorhynchus sucatio showed the highest abundance (3,859) followed by Tengra, Mystus vittatus (3,597) in traditional and bamboo root kathas, respectively in the second year while Tengra also showed highly preference for bamboo root Katha in the first year. Prawn (Macrobrachium rude) showed no special affinity for any particular katha while Mola (Amblypharyngodon mola), Chanda (Chanda ranga), Chapila (Gudusia chapra), and Darkina (Esomus danricus) showed the highest preference for traditional katha.