During a ecological study in biomasses of Choghakhour Lagoon (Charharmahal-Bakhtiary) six stations were selected. During October 1995 to September 1996 sampling were repeated three times (with Grab Walkman method). The surveys showed that the dominant aquatic organism in the lagoon is Oligochaetes which were observed in all stations and all months. after Oligochaetes, Chironomidae were the most abundant and Gammaridae were the least. According the surveys the 6th station with clay and detrus bottom (5.8± 4.2gr/m2) contained the highest biomasses and the 4th station with sandy and covered by mullusce shell debris (0.06±0.054g/m2 ) contained the least. In the winter 1995 bentose biomasses with the population of 8400±4007 and 0.025±0.021gr/m2 were the least. During different seasons water temperature and fish feeding may be important subjects in biomasses abundance fluctuation.
)