Short communication: Jellyfish of Khuzestan coastal waters and their impact on fish larvae populations

Abstract

One of the most valuable groups in the food chain of aquatic ecosystems is zooplankton. A large portion of them are invertebrate organisms with great variety of forms and structure, size, habitat and food value. The term ‘jellyfish’ is used in reference to medusa of the phylum Cnidaria (hydromedusae, siphonophores and scyphomedusae) and planktonic members of the phylum Ctenophora (Mills, 2001). Jellyfish medusa is a zooplankton which is frequently present in coastal ocean waters and all marine habitats. They are also primary predators of other zooplanktons which have significant impact on abundance and diversity of zooplankton communities that are one of the key parts of the marine food web. Most jellyfish include Hydromedusae, Siphonophora and Scyphomedusae and planktonic Ctenophora, especially in the productive warm months (Brodeur et al., 1999). In recent years, the frequency of the jellyfish in many ecosystems has increased (Xian et al., 2005; Lynam et al., 2006).