Mortalities caused by the crustacean isopod, Cirolana fluviatilis, in tropical, cage-cultured Asian seabass, Lates calcarifer: a case study from the southwest coast of India |
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Authors: | Nandiath Karayi Sanil,Pattath Ayyappan Vikas,Thaichira Bahuleyan Ratheesh,Kizhakkayil Chandy George,& Koyadan Kizhakkedath Vijayan |
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Affiliation: | Fish Health Section, Marine Biotechnology Division, Central Marine Fisheries Research Institute, Indian Council of Agricultural Research, Cochin, Kerala, India |
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Abstract: | Recurring mortalities inflicted by the cirolanid isopod Cirolana fluviatilis in the juveniles of the Asian seabass, Lates calcarifer , stocked in a cage farm in the Cochin backwaters, from November 2006 to May 2007, were investigated. Hatchery-reared fingerlings (size 8–12 cm) were cultured in floating cages and mortalities were observed after a rearing period of 1 month. The fish were found dead in the cages, with only the remnants of fish skeleton and all the flesh eaten away. Investigations revealed a very high abundance of isopods, identified as C. fluviatilis (Crustacea, Malacostraca, Isopoda and Ciroloanidae). During the first 2 months of stocking, 35% of the fingerlings died, and the cumulative mortality reached 45% in 6 months, considerably reducing the profits from the venture. Management measures for the control of the isopods are discussed. This is the first report on the isopod, C. fluviatilis , inflicting serious mortalities in a tropical cage-rearing system in the southwest coast of India. |
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Keywords: | cage culture southwest coast of India Cirolana fluviatilis isopod pest seabass Lates calcarifer mortality |
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