Parasitic diseases have recently become significant threats to tuna aquaculture in Australia and Japan. The aim of our study is to survey parasites in wild yellowfin tuna (YFT) and other Scombrid fish to identify parasite species that can be potential risks in YFT culture in Panama. Wild YFT and Scombrids were caught by fishing or obtained from local fishermen. Each fish were measured and their organs including gills, hearts, brains, gastro-intestinal tract, muscle, kidney, and/or liver were examined under a light stereomicroscope. Any parasite specimen found were photographed and fixed in ethanol for morphological and molecular analyses. In wild YFT, we found Didymocystes in gills arch and gastrointestinal mucosa. Trichodina and Copepods were found in gills and Digeneans, Acantocephalans, Nematodes and Cestodes were obtained from stomach. In addition, we found scuticociliate possibly Uronema sp. from a brain of one YFT. No parasites were detected from the YFT juveniles reared in sea cages for about 4 weeks at Achotines Experimental Station. From wild Scombrids, we identified several parasites including gill flukes and trematodes. Furthermore, we detected myxozoan infection in the trunk muscle of Pacific sierra Scomberomorus sierra caught off the coast of Tonosi, Panama. Morphological and molecular analyses reveal this is a new species of genus Kudoa and we described this species as Kudoa rayformis n. sp. The species formed pseudocysts in myofibers and infection was subclinical. The myxospores possessed four polar capsules and spore valves, one of which had a distinct filamentous extension. This unique morphological characteristic of the myxospore validated this as a new species of Kudoa. In the study, we did not detect any species, except for scuticociliate in brain, that can be a potential problem in tuna culture in Panama. However, more studies are necessary for detailed risk assessment of parasitic diseases in cultured YFT.

Acknowledgements

The authors we thanks to Licdas. Maruslybel López, Diana Pérez, Anna Núñez, Ing. Amado Cano, Ing. Dario Sandoval, Leyson Solís. Achotines Laboratory fishing staff, Captain: Cota, Daniel Mancilla, Carlos, Agustin, Dario, Inn. El Ciruelo Beach and Arenal Beach Fishermans (Pepino, Teto, Nego). Fish Patology Laboratory. Staff, to Shirahama Fisheries Experimental Station, Kinki University 2015. (Dr. Shin Sam Phil, Katzuki, Hamano, Nishimura) in special to Sho Shirakashi, PhD and Keitaro Kato, PhD, for the photografy. Sabbah University, Malassia students (Aisha Faisal).

* Presenting author

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