Fish parasites are used to monitor long-term change in finfish grouper mariculture in Indonesia. A total of 210 Epinephelus fuscoguttatus were sampled in six consecutive years between 2003/04 and 2008/09 and examined for parasites. The fish were obtained from floating net cages of a commercially run mariculture facility that opened in 2001. The fauna was species rich, consisting of ten ecto- and 18 endoparasite species. The ectoparasite diversity and composition was relatively stable, with the monogeneans Pseudorhabdosynochus spp. (83-100% prevalence, Berger-Parker Index of 0·82-0·97) being the predominant taxon. Tetraphyllidean larvae Scolex pleuronectis and the nematodes Terranova sp. and Raphidascaris sp. 1 were highly abundant in 2003/04-2005/06 (max. prevalence S. pleuronectis 40%, Terranova sp. 57%, Raphidascaris sp. 1 100%), and drastically reduced until 2008/09. These parasites together with the prevalence of Trichodina spp., ecto-/endoparasite ratio and endoparasite diversity illustrate a significant change in holding conditions over the years. This can be either referred to a definite change in management methods such as feed use and fish treatment, or a possible transition of a relatively undisturbed marine environment into a more affected habitat. By visualizing all parameters within a single diagram, we demonstrate that fish parasites are useful bioindicators to monitor long-term change in Indonesian grouper mariculture. This also indicates that groupers can be used to monitor environmental change in the wild. Further taxonomic and systematic efforts in less sampled regions significantly contributes to this new application, supporting fish culture and environmental impact monitoring also in other tropical marine habitats.

The present study represents the first report on the gastrointestinal parasite fauna infecting the free-living and alive Indo-Pacific bottlenose dolphins (Tursiops aduncus) inhabiting waters of the Red Sea at Hurghada, Egypt. A total of 94 individual faecal samples of the examined bottlenose dolphins were collected during several diving expeditions within their natural habitats. Using classical parasitological techniques, such as sodium acetate acetic acid formalin method, carbol fuchsin-stained faecal smears, coproantigen ELISA, PCR and macroscopical analyses, the study revealed infections with 21 different parasite species belonging to protozoans and metazoans with some of them bearing zoonotic and/or pathogenic potential. Four identified parasite species are potential zoonotic species (Giardia spp., Cryptosporidium spp., Diphyllobothrium spp., Ascaridida indet.); three of them are known to have high pathogenic potential for the examined dolphin species (Nasitrema attenuata, Zalophotrema spp. and Pholeter gastrophilus) and some appear to be directly associated with stranding events. In detail, the study indicates stages of ten protozoan species (Giardia spp., Sarcocystis spp., Isospora (like) spp., Cystoisospora (like) spp., Ciliata indet. I and II, Holotricha indet., Dinoflagellata indet., Hexamita (like) spp., Cryptosporidium spp.), seven trematode species (N. attenuata, Nasitrema spp. I and II, Zalophotrema curilensis, Zalophotrema spp., Pholeter gastrophilus, Trematoda indet.), one cestode species (Diphyllobothrium spp.), two nematode species (Ascaridida indet, Capillaria spp.) and one crustacean parasite (Cymothoidae indet.). Additionally, we molecularly identified adult worms of Anisakis typica in individual dolphin vomitus samples by molecular analyses. A. typica is a common parasite of various dolphin species of warmer temperate and tropical waters and has not been attributed as food-borne parasitic zoonoses so far. Overall, these parasitological findings include ten new host records for T. aduncus (i.e. in case of Giardia spp., Sarcocystis spp., Cryptosporidium spp., Nasitrema spp., Zalophotrema spp., Pholeter gastrophilus, A. typica, Capillaria spp., Diphyllobothrium spp. and Cymothoidae indet.). The present results may be used as a baseline for future monitoring studies targeting the impact of climate or other environmental changes on dolphin's health conditions and therefore contribute to the protection of these fascinating marine mammals.

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