|Green, Bartholomew - Bart|
Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/22/2005
Publication Date: 1/5/2006
Citation: Wiese, N., Engle, C., Trimpey, J., Quagrainie, K., Green, B.W. 2006. Reducing catfish farm losses due to dockages assessed by processing plants. Journal of the World Aquaculture Society. 37:60-73. Interpretive Summary: Channel catfish, Ictalurus punctatus, processing plants set specifications for fish delivered to the plant in order to maintain efficiency of the processing operation and meet market requirements. Dockages, which are reductions in either the fish weight delivered or the price to be paid, are assessed for fish that fail to meet plant specifications and are subtracted from the total payment due farmers for the fish delivered. This study was conducted to quantify common dockages, examine seasonal and yearly variations in dockages assessed, and determine optimal production practices given various dockage scenarios. Dockage occurred in 95% of the catfish loads surveyed and the lost revenue from dockage averaged $0.066/kg of catfish marketed. This study suggests that there are combinations of management strategies and grading technologies that can be used to minimize losses due to dockage. Higher farm revenues would result if larger farms, in response to increased minimum market size of fish, were to grow fish of the same age to market size or to remove the smaller fish from the harvest of ponds stocked with different aged fish before sending fish to the processing plant. On smaller farms that stock multiple age groups of catfish in production ponds, higher farm revenues would be generated if smaller fish were removed from harvested fish either using passive grading technology where up to 10% of the fish arriving at the processing plant would be small, or using active (mechanical) grading technology where all fish arriving at the processing plant would meet plant specifications.
Technical Abstract: Dockages can have a significant effect on catfish, Ictalurus punctatus, farm revenues. This study was conducted to quantify common dockages, examine seasonal and yearly variations in dockages assessed, and determine optimal production practices given various dockage scenarios. A convenience survey of invoice records from 30 commercial catfish farms and ten processing plants provided 3,686 daily catfish load records that were used to quantify dockages. A linear programming model was developed to examine optimal production practices given 11 alternative production scenarios with five size grading technologies subject to 24 types and levels of dockages. The survey revealed that 95% of catfish loads delivered to processing plants between 1997-2002 were assessed dockages that resulted in average losses of 2.45% per load or $0.066/kg of catfish marketed over the study period. Out-of-size discounts constituted the greatest losses. Dockage losses can be reduced by shifting either to longer-term single-batch production or more intensive grading. Longer-term production results in fewer smaller fish that would incur dockage losses. However, cash flow constraints require more intensive early-season grading. The grader choice depended on the dockage tolerance level and rate, the frequency distribution of sizes of catfish in the population, the efficiency of the grading technology, and the cost of the grading method. Larger farms minimize losses with intensive active grading (UAPB grader).