Ichthyofauna Diversity and Its Distribution in a Low-Saline Lake of Indonesia

Abstract

Lake Siombak is a tidal lake that is an estuary around the lake covered with various mangrove trees. It is interesting to study the fish's spatial and temporal distribution as a unique and distinctive tidal lake ecosystem. This research was conducted for a year (from September 2018 to August 2019). Fish sampling was performed by installing gill nets (mesh size 1 inch) and cast nets (mesh size 0.5 inch). Gill nets and cast nets were installed at high and low tides during the full moon. This research showed that there were 27 species of 20 families. Tilapia, Mudskipper, Indo-pacific tarpon, and mainly Rice Fish are always found in Lake Siombak. The fish group at Lake Siombak consists of freshwater fish (mainly: Tilapia, Catfish, and Snakehead), brackish fish (mainly: Mudskipper, Rice fish, and Indo-pacific tarpon), and marine fish (mainly: Milkfish, Kanda mullet, and John's snapper). The actual resident in Lake Siombak consists of Oryziidae, Tilapia, and mudskipper. Other fish are temporary resident fish except for Lutjanidae and Scatophagidae as visitor fish during high tide and high salinity periods (dry season) and Synbranchidae during low salinity (rainy season).

The relationship between water quality and aquatic organisms in tidal lakes, Medan-Indonesia

“…Data collection on water quality and aquatic biology is carried out every full moon at high and low tide. Water quality data refers to water biology and is further processed from previous research by [2,4,5,6,7,8,10].…”

“…Other notable species in Siombak Lake include herring fish (M. cyprinoides), eel fish (A. bicolor), and jellyfish (A. aurita). Siombak Lake's biological community includes fresh, brackish, and marine biota, as well as newcomers and settlers [3,4,5,67,8,12].…”

“…Similarly, fish are spatially and temporally closely related to their food sources, namely, zooplankton, crustaceans, and mollusks. The waters of Siombak Lake are a food search area for fish organisms, both fresh and marine fish that alternately enter the lake according to salinity conditions [5,8]. Based on correlation and regression and the descriptive analysis between salinity and aquatic organisms in Siombak Lake, it can be said that salinity influences the distribution and number of plankton., larvae, crustaceans, and fish species and populations.…”

“…Some mangroves develop around the lake's perimeter [3,4]. The aquatic biota of Siombak Lake consists of groups of freshwater fish, brackish, and marine creatures [5][6][7][8]. Siombak Lake serves as catchment area for water, a flood control zone, a fishing area for fish, shellfish, and crabs, and a tourist attraction.…”

“…Various studies of Siombak Lake have been conducted, including on morphology and hydrodynamics as well as the status and profile of lake water quality [1,2,10,11]. Studies on aquatic biodiversity such as fish, crustaceans, mollusks, and plankton have also been conducted [3][4][5][6][7][8]. In addition, studies on mangroves and bird and mammal biodiversity have been reported in 2020 and 2021 [3,12].…”