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Site selection and production performance of rainbow trout (Oncorhynchus mykiss) cage operations in small farm reservoirs: the Western Cape experience, South Africa
Author(s) -
Maleri Monika
Publication year - 2008
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2008.02054.x
Subject(s) - rainbow trout , fishery , biology , cape , fish farming , water quality , aquaculture , production (economics) , agriculture , ecology , fish <actinopterygii> , geography , macroeconomics , archaeology , economics
Cage farming of rainbow trout ( Oncorhynchus mykiss ) has expanded rapidly into private farm reservoirs of the Western Cape. During the grow‐out season 2006, water quality problems such as increased mortality rates and off‐flavour of the final product caused economic losses. To set criteria for improved site selection, water quality information of surface and near‐bottom water was correlated with morphometric reservoir data, fish production data as well as the observed production difficulties. The data revealed good linkage between reservoir information and fish production data as well as production problems. The production problems correlated ( P <0.01) with single water quality parameters so that suggestions for risk management indicators can be made. By ranking the data, threshold values for better production practice were determined. Thereafter, reservoirs of a minimum surface area of at least 3 ha would be recommended as well as reservoirs with good water exchange rates (>1 per year) to avoid oxygen problems. Reservoirs of larger surface area (>5 ha) produced significantly larger fish that grew faster and showed lower mortality rates.