The Comparison Of Diversity And Abundance Of Macrozoobentos In Three Farms Of Chinese Carps In Guilan Province

The comparison of diversity and abundance of macrozoobentos at three chinese cyprinids fish farms sampling for determination of abundance and diversity of macrozoobentos, at tree 1- hectar farms of chinese carps in Gulian province was done every 15 days for 8 months. Used a 272 ' Cm2 grab, for sampling of sediments at entrance, middle part, and exit of farms. Resalts showed 3 groups of macrozoobentos in sediments of farms. That including: Tubificidae, Chironomidae and Gastropoda. The total abundance percent of this groups was 77.18, 20.26, and 2.57 respectively. The mean abundance of Tubificidae in 3 farms in Spring, Summer and Autumn was 279, 864 and 278 ind/m2 respectively. Frequency of this group in Summer was significantly more than spring and Autumn ( p0.05). The mean abundance of Chironomidae in spring, summer and Autumn in 3 farms, was 221, 87, and 64 pieces/m2 respectively. The abundance of this group in spring was significantly more than Summer and Autumn (p0.05). The mean biomass of chironomidae in sediments of farms in Spring, Summer and Autumn was 2.3, 0.67 and 0.4 g/m2 respectively. The biomass of chironomidae in spring was, significantly more than Summer and Autumn (p0.05). The mean abundance of Gastropoda in sediment of 3 farms in Spring, Summer and Autumn was 4, 14 and 27 ind/m2 respectively. The abundance of this group in Autumn was significantly more than Spring and Summer and in Summer more than Spring. On survey of intestine content of common carp (Cyprinus carpio), seen Chironomidae and gastropoda. The percent of total organic matter at entrasnce to exit of farms increased. The total percent of T.O.M in entrance, middle and exit of farms was 8.67, 10.97, and 13.21 respectively. In determination of grain size and composition of sediments of farms, the percent of sand plus silt and clay was 61.31 and 36.34 respectively. Also the mean of phisical-chemical parameters, such as, water temperature, dissolve oxygen, transparency, and pH were, 26.25 oc, 7.64 mg/l, 34.22 cm and 7.90 respectively.