In Baluran National Park, the coastal area is mostly dominated by mangrove forest. It is a natural habitat for mudskipper (the Gobidae family) which is able to resemble colours of water around it and sink into substrate. The interesting , five students of Biology Study Program of the Faculty of Mathematics and Natural Sciences recently conducted a study on the mudskippers habitat in mangrove ecosystem along the coastal area of Baluran National Park, East Java. They are Fauzan R. P., Hefi M. S., Gana Y. P., M. Fajar H., and Heny Rahmawati. The research aims at revealing the climatic, edaphic and vegetation characteristics of the ecosystem.

According to Gana, they explored and observed the fish along the tracking bridge and determined 3 spots for data collection. They also measured and recorded the climatic and edafic characters which include light intensity, substrate temperature, substrate pH, water temperature, water pH, salinity as well as vegetation character on each spots, and collected the sample of the fish to identify.

The results show that mudskippers live in mud substrate with 0—30 cm height which has low light intensity ranging from 57—78 x 1000 lux. The low light intensity is caused by the mangrove vegetation which shades the area.

“Substrate temperature for the fish ranges from 31oC—33oC, with substrate pH ranging from 6,6—6,8 and water pH ranging from 6,4—6,7. This substrate pH tendency is caused by such high organic content in the substrate which comes from torn pieces of rotten mangrove or animal faeces,” he said.

Salinity characteristic in mudskipper habitat ranges from 2,4 grams to 3 grams per 100 ml of water which is considered low (0,5%--3%). It shows that the fish is able to tolerate low salinity.

Gana explains that mangrove vegetation (Rhizophora sp) is the natural habitat for mudskippers because it has big and dense prop roots so that it is considered invulnerable to waves. Beside prop roots, it also has cane roots which function to hold the trunk. From the observation, mangrove vegetation was used by the fish as shelter. It will jump to shaded roots to protect itself from predators. (witono)