World Journal of Fish and Marine Sciences 3 (1): 67-70, 2011 ISSN 2078-4589 © IDOSI Publications, 2011 Corresponding Author: S.Ravikumar, School of Marine Science, Department of Oceanography and CAS, Alagappa University, Thondi Campus, Thondi, Ramanathapuram Dist-623409, Tamil Nadu, India. E-mail: ravibioteh201321@gmail.com. 67 Antimicrobial Activity of Sponge Associated Macroorganisms Against Fish Pathogen S. Ravikumar, M. Venkatesan, M. Ajmalkhan and M. Dhinakarraj 1 1 2 2 Department of Oceanography and CAS, School of Marine Science, Alagappa University, 1 Thondi Campus, Thondi, Ramanathapuram Dist-623409, Tamil Nadu, India Department of Life Sciences, PRIST University, Thanjavur, Tamil Nadu, India 2 Abstract: Antimirobial potential of sponge associated microorganisms have been dealt for a couple of centuries, but the bioactivity of sponge associated macroorganism have not been attempted so far. The present study was carried out to find out the sponge associated macroorganism and their bioactive potential against chosen fish pathogens. Marine sponges were monthly collected by scuba diving at sampling station viz Thondi. Five sponge samples viz., Clathria vulpine, Stylissa carteri, Hyattella intestinalis, Clathria indica and Haliclona grant were collected from Palk Starit region. Associated macroorganism viz., Hypnea valentiae sponge and Nereis sp. The bioactive potential of sponge extract and associated macrofaunal and floral extract was showed that, the crude extract from Clathria vulpine showed maximum average zone of inhibition (10.25mm) against Bacillus subtilis and Vibrio harveyi. Among the assoiated macroorganisms, the seaweed Hypnea valentia and Nereis sp showed maximum average zone of inhibition (9.25 and 7.5mm). The overall antimicrobial activity assessed from the above results indicated the presence of active constituents in the extractions of sponges and assoiated macroorganisms which can be exploited for the production of lead molecules which are of use in pharmaceutical industry. Key words: Antibacterial activity %Sponges %Associated macroorganisms %Fish pathogens INTRODUCTION under the class Demospongiae. Since sponges are simple Sponges (Phylum Porifera) are evolutionarily ancient developed potent chemical defensive mechanism to metazoans that have existed for 700–800 million years. protect themselves from competitors and predators as well They not only populate the tropical oceans in great as infectious microorganisms. Studies show that abundance, but also occur in temperate waters and even secondary metabolites in sponges play a crucial role in in freshwater [1-2]. Marine sponges are widely distributed their survival in the marine ecosystem [7]. Sponges have from intertidal zones to thousands of meters deep in the bioactive potential by the presence of active ingredients ocean [3]. They are simple multicellular invertebrates preserve in sponges themselves or their microbial attached to solid substrates in benthic habitats. Sponges symbionts of chemicals that may be used to control are filter feeders, having numerous tiny pores on their viruses, bacteria, tumors and fungi [8]. Previous studies surface, which allow water to enter and circulate through on mangrove plant parts and its major chemical classes a series of canals where microorganisms and organic displayed various level of biological activities such as particles are filtered out and eaten [4]. There are mainly antibacterial, antifungal, antiplasmodial, cytotoxic, three classes of sponges, namely the Calcarea (five orders antifouling, hepatoprotective, ichtyotoxic, cytotoxic and and 24 families), Demospongiae (15 orders and 92 free radical scavenging activities [9-16]. These natural families) and Hexactinellida (six orders and 20 families). products have interesting biomedical potential, So far about 15,000 species of sponges have been pharmaceutical relevance and diverse biotechnological described, but their true diversity may be higher [5]. Most applications [17]. The biomedical and pharmaceutical of them occur in the marine environment and only about importances of these compounds are attributed to their 1% inhabit freshwater [6]. Most of the species are placed antiviral, antitumor, antimalarial, antimicrobial and general and sessile organisms; during evolution they have