~ 255 ~  Journal of Entomology and Zoology Studies 2015; 3(3): 255-257 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2015; 3(3): 255-257 © 2015 JEZS Received: 10-04-2015 Accepted: 15-05-20105 Abid A Ansari Department of Biology, Faculty of Sciences, University of Tabuk, Tabuk, 71491, Saudi Arabia Correspondence: Abid A Ansari Department of Biology, Faculty of Sciences, University of Tabuk, Tabuk, 71491, Saudi Arabia Relative density of Istiblennius dussumieri along some selected coastal sites of the Red Sea, Tabuk, Saudi Arabia Abid A Ansari Abstract Rock skippers (Istiblennius dussumieri) are important for their biological and ecological studies and used as potential indicator to investigate the ecological conditions of coastal waters. They are considered as an important tool for the environmental monitoring and assessments of coastal aquatic ecosystems. In this study we measured relative density of rock skipper at 3 sampling stations namely Haql, Sharmaa and Duba in varying environmental conditions of Tabuk during the year 2014. The results of this study showed a direct relation between relative densities of rock skipper in response to monthly variations in climatic conditions of Tabuk. Rock skippers are very sensitive to aquatic environmental conditions and their potential would help the researchers working on this species. Keywords: Rockskipper; Relative density; Bio-indicator; Coastal waters 1. Introduction Rock skippers are studied as a bio-indicator in environmental monitoring and impact assessments of various contaminants in coastal waters [1] . This potential would be beneficial for new researches on this species especially for its ecological importance in detecting pollution levels in coastal water ecosystems [2] . The behavioral, physiological, histological, and embryological changes in rockskippers are considered as strong indicators for the monitoring and assessment of coastal water quality. They are strongly capable to accumulate higher concentrations of water contaminants in their body tissues [3] . The species is limited to humid environment only and they have adopted amphibians like habits and habitats, as they respire through skin [4, 5] . Reproductive behavior and life cycle patterns of rock skippers have been studied by various workers [6, 7] . To evaluate the population and community structure of the rock skipper’s different parameters like relative density, abundance, frequency, growth and mortality are used. Some of the species are now considered as endangered due to perturbation in their natural habitat and contamination of costal environments [8] . Human and rock skipper interact with each other due to their tolerance to organic pollution and habitats close to the coastal settlements of human population [9] . 2. Materials and Methods Three coastal stations of the Red Sea viz. Haql (29 o 17’9.9” N 34 o 56’ 18.9” E), Sharmaa (28 o 1’ 27.9” N 35 o 16’ 9.9” E) and Duba (27 o 20’ 57.3” N 35 o 41’ 46.2” E) were selected for this study (Fig.1). Relative density of I. dussumieri was studied on monthly basis (January 2014 to December 2014) to investigate the impact of varying environmental conditions on species structure. After every 300 meters five sampling sites from each station (Haql, Sharmaa and Duba) were selected starting from the residential area of the city near to the sea coast. Qualitative survey for the relative density of I. dussumieri along the selected coastal areas of the Red Sea was carried out using quadrates of 1m 2 . At each site five sampling quadrates were studied as replicates. Relative density was calculated as: Total number of individuals of I. dussumieri in all the sampling units ----------------------------------------------------------------------------------------- × 100 Total number of sampling units studied