Parasites of commercially important fish species from the southern Java coast, Indonesia, including the distribution pattern of trypanorhynch cestodes

Abstract

A total of 118 commercially important fish species from the southern Java coast, Indonesia, were studied for the parasite fauna. The fish belonged to the oceanic families Gempylidae (Gempylus serpens, Thyrsitoides marleyi), Trichiuridae (Trichiurus lepturus) and Bramidae (Brama dussumieri). In addition, a single specimen of the deep-sea fish species Alepisaurus ferox and the pelagic Tylosurus crocodilus crocodilus were studied for comparison. A total of 38 parasite species was found, and 23 new host records could be established. The most diverse component community was found in T. lepturus and G. serpens with 17 and 16 species/taxa, respectively. The infracommunity was highest in G. serpens and T. marleyi with a mean of 9.1 and 6.5 species. The cestode order Trypanorhyncha recorded as extraintestinal larval stages was the most diverse taxon with 13 different species, followed by the Crustacea (8), Nematoda (5), Digenea (5) and Acanthocephala (3). The trypanorhynch Mixonybelinia lepturi was the parasite with the highest intensity of infestation, and was recorded from G. serpens, T. marleyi, T. lepturus, B. dussumieri and A. ferox at a prevalence of 10- 100% and an intensity of 1-243. The host specificity of the tentaculariid trypanorhynchs was low, with 4 species infesting 2 up to 5 of the studied host fish species. The overlapping infestation pattern in fish from entirely different families underlines the low specificity of trypanorhynchs in their second intermediate hosts, and their ability to infest various fishes without respect to their host phylogeny. The helminths Nybelinia africana, Mixonybelinia lepturi, Tentacularia coryphaenae, Scolex pleuronectis, Anisakis sp. and Gorgorhynchus cf. robertdollfusi are characteristic for the studied fish species within the oceanic, into the deep-sea reaching environment along the tropical outer continental shelf region off the Java coast. A high prevalence of infestation of 97-100% with the zoonotic Anisakis sp. demonstrates a high risk of predatory fish to get infested. T. lepturus as an economically important fish species within the region as well as other oceanic and pelagic fish from the southern Java coast should be cooked well before consumption or deep frozen before further processing to prevent any risk of the Anisakis-infection in humans, locally as well as on the international market. Keywords: fish parasites, Indonesia, deep-sea fish, zoonotic parasites, Anisakis spp., anisakiasis, Trypanorhyncha, biodiversity, vertical distribution, zoogeography