Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 1493
Title: Water Quality in Tilapia Transport: From the Farm to the Retail Store
Author: John Colt, Tracey Momoda, Rob Chitwood, Gary Fomshell, C. B. Schreck
Publication Year: 2011
Journal: North American Journal of Aquaculture
Volume: 73
Pages: 426-434
DOI: DOI: 10.1080/15222055.2011.629946

 Nile tilapia (Oreochromis niloticus) are routinely transported 1,200 to 1,400 km from Idaho to the greater Vancouver area, British Columbia for the live markets. Direct hauling mortality is typically very low, but significant economic losses occur during retail holding due to deterioration of physical appearance that results in fish that cannot be sold and mortality. To try to address this problem, information was collected on hauling systems and protocols, water quality in hauling tanks, holding systems and management, and water quality in the retail holding systems. During hauling, fish are exposed to high levels of dissolved oxygen, carbon dioxide, and bacteria. The transfer of fish from hauling systems to retail holding systems can subject fish to rapid temperature, dissolved oxygen, carbon dioxide, and pH changes. Problem areas in retail holding include low water temperatures, high un-ionized ammonia concentrations, and elevated gas supersaturation levels. Determination of the causes of high mortality in transportation and retail holding is difficult to clearly identify because of sampling difficulties and commercial restrictions; improvements in hauling protocols may depend on simulated hauling experiments followed by commercial verification.