The investigation on fish composition at artificial reefs deployed on different substrates off Urkmez Coast

Abstract

The first scientific artificial reef study was carried outin Izmir Bay, Turkiye the year of in 1991. Many coastal villages on the coast of Aegean Sea were interested in artificial reefs and applied their own projects. But the development of scientific knowledge on artificial reefs remained slower the application. The aim of this study is that new informations should be taken from artificial reefs. Great deals of environmental factors have several effects on fish assemblage of artificial habitats. Not only depth, and location, etc... but also surrounding structure of substrates has a significant effect. Rocky, muddy and sea grass bottoms ay attract various species and number of fish. The main aim of the study was to determine fish species richness, abundance and biodiversity in artificial reefs deployed on muddy and sea meadow bottoms. In 1998, to prevent illegal fisheries and improve small scale fisheries, 160 pentagon-dome blocks (2 m(3) each) contain 10 reef sets were deployed in the depth of 18-21m, Urkmez.. A reef set having 50 m3 bulk volumes consists of 16 blocks. Two of sets were deployed on sea meadow floor and the others on muddy floor. Divers recorded monthly, fish speciesand abundance by visual census method using SCUBA for different substrates. Each observation was carried out by the same diver and time of the day (10.00 - 12.00) to standardize and reduce bias. 12 families and 36 species were recorded over sea meadows and 10 families and 25 species over muddy area habitat. Furthermore, fish residency and diversity on reefs for different substrates were determined. Similarity index were used to compare fish compositions variations of fish assemblage to reefs deployed on different substrates were analysed and also differences distinctions between substrates were compared.