Hengam Island with coral and reef ecosystem is located in the south of Qeshm Island in the Persian Gulf. Biomass of Coral and reef fish was estimated by random block classification by Underwater Visual Census Method (UVCm), in five stations (St.) from Sep.2020 to Apr.2021 seasonally. 38 species of coral and reef fish belonging to 21 families were identified, that Pomacentridae of coral fish with 7 species had the highest number. The upper and lower confidence interval of these values were estimated by 2000 replications by the bootstrapping simulation method in stations. The distribution of the number and standing biomass of fishes in each season and station was determined by one-way ANOVA with tuky test (P=0.95) (P <0.05).
The highest of total biomass with 703.99 (Kg/km2), in S. ghobban, and the lowest total biomass belonging to Ecsenius pulcher species, with 0.1 (Kg/km2), is estimated. In addition, the highest and lowest number total is calculated in Abudefduf vaigiensis, with 1186 (N/km2), and the lowest in Chrysiptera spp., with 2 (N/km2). Also, among the stations, the highest standing biomass was 233.75 (Kg/km2), belonging to L. fulviflamma in Jetty St. and the lowest number was concluded for E. pulcher, 0.11(Kg/km2) at Abbas station. The maximum number and standing biomass was estimated 58(N/km2) in Abbas St. and 16.36 (Kg/km2) in Jetty St. (Feb.2021), and the minimum of these values was calculated at Jetty, Khenzi and Ghil St. with 6 (N/km2) and 0.92(Kg/km2) in Khenzi St.(Sep.2020).
The results of this research showed that it seems the type of substrate cover, habitat heterogeneity, hilly reefs, and being away from stress sources are more effective than the size of the habitat in the amount of biomass and the number of coral fish in the stations.
Keywords: coral-fish, Biomass, Bootstrapping, UVCm, Hengam Island, Persian Gulf