THE BIOMASS AND DISTRIBUIION OF PSEUDOCUMIDAE IN THE SOUTHERN-WEST COASTS OF THE CASPIAN SEA (GUILAN PROVINCE)

The most part of the fauna population in the Caspian Sea comprised invertebrates that is dominated by benthic organisms. Cumacea belongs to Arthropoda phylum, class of Crustacea and has an important role as food for sturgeon fishes in the Caspian Sea. This study was performed from autumn 1992 to summer 1993 in sixteen transects and each transect had four stations located at 10,20, 50 and 100 m depths.
The survey revealed that the maximum mean biomass of this family was observed at 10 m depth in transect 15 with 9.62 gim2 and the minimum was observed at 20 m depth in transect 1 with 0.07 g/m2. The greatest biomass of this family was observed in spring with average biomass of 6.48 g/m2 and the lowest biomass was observed in autumn-winter with average biomass ofl.47 g/m2. The maximum and minimum mean biomass was observed at 100 m and 10 m depths respectively. The average biomass of this benthos had significant differences in different depths and seasons (P<0.05).
The amount of T.O.M had high and considerable changes in different depths with a range of 3.55-10.37% for depths of 10 to 100m, respectively. Also the maximum percentage of sand in sediment was observed in 10m depth with value of 58.64% and minimum value was 34.73% in 100m depth. The mean biomass of this aquatic organism was 4.75 ± o.45 g/m2 in eastren area and 3.59±0.31 g/m2 in western area of this province. Nonparametric statitical analysis of Kruskal- Wallis showed significant diffrence between mean biomass in this two areas (P < 0.05).