The condition and composition of seagrass and mollusca on Biak island, Papua

Abstract

Abstract This research was purposed to assess coverage and species distribution of seagrass as well as mollusca in Biak Island, Biak Numfor Regency, Papua. Field sampling was conducted in February, March and September 2017 at 18 observation stations. Eight seagrass species were recorded during the sampling period namely Thalassia hemprichii, Enhalus acoroides, Halodule uninervis, Halodule pinifolia, Syiringodium isoetifolium, Cymodocea rotundata, C. serrulata, and Halophila ovalis. The highest coverage was T. hemprichii, followed by C. rotundata and the least was C. serrulata. The range of seagrass coverage from 5.11% (St.1) to 75.76% (St.17) with the average of coverage in Biak was 35.7%. Furthermore, there were 4 groups based on Bray-Curtis similarity according to the seagrass assemblage in the research area. In addition, a total of 156 molluscan species were recorded consisted of 123 species from gastropod and 33 species from bivalvia. The most distributed species from gastropod were Conomurex luhuanus and Canarium urceus, while from bivalvia was Anadara antiquata. Station 15 has the highest species number with 33 species and the lowest, with just 9 species, were found at station 1 and 7.