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

• Published in: Aquaculture research Vol. 40; no. 14; pp. 1626 - 1633
• Main Authors: Sanil, Nandiath Karayi, Vikas, Pattath Ayyappan, Ratheesh, Thaichira Bahuleyan, George, Kizhakkayil Chandy, Vijayan, Koyadan Kizhakkedath
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.09.2009
• Subjects: cage culture; Cirolana fluviatilis; Dicentrarchus labrax; isopod; Isopoda; Lates calcarifer; Marine; mortality; pest; seabass; southwest coast of India; ISW, India, Kerala, Ernakulam Dist., Cochin, Cochin Backwater
• ISSN: 1355-557X; 1365-2109
• DOI: 10.1111/j.1365-2109.2009.02263.x

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.