THE DIVERSITY OF FISH IN SEAGRASS BEDS AND BARE SAND CHANNEL IN TABLOLONG WATERS, KUPANG REGENCYYohanes Merryanto and Alfred G.O. Kase
Seagrass ecosystems in Tablolong waters have important values related to the availability of fish resources. However, this seagrass meadow experiences a lot of fragmentation in the form of empty sand areas without vegetation (bare sand), both in the form of channels and tidal pools which provide many small living spaces (microhabitats) that are interesting for aquatic ecology studies. The aim of this research was to analyze the diversity and dominance of fish species in the seagrass beds and bare sand channels, as well as to determine the dominant species of seagrasses in the seagrass beds. The study was conducted through direct observation by catching fish specimens using gillnets (# 1.5 inches and #1.25 inches, @ length 20 m x height 1.5 m) and scoop nets three (3) times sampling with time intervals. 7-10 days in the time period of October-November 2021. The results showed that the seagrass beds in the Tablolong Waters are classified as heterospecific from at least 6 (six) seagrass species with an average density of all species reaching 219.2 stands/m2 and an average cover of 40.0% (medium level of cover) where Thalassia hemprichii was the dominant seagrass species in terms of density value (more than 50%of total species) and cover value almost 40% of total species. The fish collection obtained as a whole consisted of 22 fish species from 17 families with 86 individuals where the fish community in the seagrass beds (9 species, 8 families, 17 individuals) was recorded to be lower than the fish community in the empty sand tunnel (13 species, 11 families, 49 individuals), each with a ratio of 41%:59% in species, a ratio of 47%:65% in families and a ratio of 43%:57% in the number of individuals. The status of the fish species that dominates was the occasional visitor fish of 90% (20 species) compared to seasonal visitor fish and whole life resident fish of 5% (1 species). The index value of fish species diversity in seagrass beds was moderate (Hâ 2) which was lower than the fish community in empty sand tunnels which was high (Hâ 4) and the total number of fish species on Tablolong beach was high (Hâ > 4). The fish species dominance index value showed that in both fish in seagrass beds (D 0.28), in empty sandtunnels (D 0.11), and the whole area (D 0.25) in Tablolong waters there were no dominant fish species. So that the structure of the fish community tends to be stable or the diversity of fish species tends to be high.