Effects of shrimp effluents on mudskippers (Gobiidae: Oxudercinae) in the northern Persian Gulf

Abstract

Shrimp effluents can affect environmental conditions of the receiving ecosystems, and cause noticeable alterations in the residing communities. Mudskippers, as benthic fish with limited movement, could be affected by aquaculture-induced changes in environmental factors. These changes and subsequent responses of mudskipper assemblage to them, in the northern Persian Gulf, were studied. Some physicochemical and biological characteristics of the environment in addition to density, length, weight, and condition (i.e., Fulton's condition factor) of the residing mudskipper species (i.e., Boleophthalmus dussumieri and Periophthalmus waltoni) were measured in the control and impact sites. The results showed significant increases in the organic content (TOM and BOD), chlorophyll a, pH, total nitrogen and phosphorus, and fine particle fraction of sediments and decrease in DO due to shrimp effluent discharge. Furthermore, significant increases in the studied mudskippers' biological properties, except density of P. waltoni, in the sites receiving effluents were observed. It appears that increases in the fauna and flora of the impact sites have provided mudskippers with more food sources, and increased their lengths, weights, and densities (i.e., the overall environmental changes seem to be desirable for the mudskippers). The higher condition factors of the individuals inhabiting polluted sites indicate that not only these species can endure adverse changes in environmental circumstances, but also are in healthy physical conditions.