February 15-18, 2009 Washington State Convention Center Seattle ...

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TESTING FEED RESPONSE METHODS OF INVENTORY ESTIMATION FOR CHANNEL
CATFISH Ictalurus punctatus PRODUCTION
Pratheesh Omana Sudhakaran, David Heikes and Carole Engle
Department of Aquaculture/Fisheries
University of Arkansas at Pine Bluff
Pine Bluff, Arkansas 71601 USA
pomana@uaex.edu
The multiple batch production system commonly used in commercial catfish production results in a mixture of sizes of fish
in the pond. Accurate, cost-effective inventory estimation would improve financial and production management. Several inventory
estimation methods used by industry consultants and advisors are based on feeding response of fish. Daily feeding
response is known to be variable; hence, biomass estimates based on daily feed response would be expected to be variable. No
systematic tests of the variability and accuracy of these methods have been conducted. Datasets from experimental trials of
catfish production in single and multiple batch systems at various densities were used to estimate and compare: 1) the variation
in feeding rates, and 2) compare actual catfish biomass with biomass estimated with five different methods. Coefficients
of variation (CV) of quantity of feed fed per treatment were calculated for each week for each pond within three temperature
ranges. Analysis of variance (ANOVA) was used to compare CVs calculated using daily feed, two-day means, three-day means
and four-day means for each temperature range, for each stocking density and feeding treatment, for both single and multiple
batch. Stocking density and temperature had no significant effect on variation of feeding rates in either single or multiple batch
production. However, in single batch production, the four-day average of daily feed showed a significantly lower CV (17%)
than daily feed (mean CV= 38%), two-day means (mean CV= 27%) or three-day means (mean CV= 24%) (Figure 1a). In
multiple batch production, the three-day average of daily feed had a significantly lower CV (24%) compared to the daily feed
(mean CV= 49%) and 2-day average (mean CV= 34%) but was not significantly different from the four-day average (mean
CV= 23%) (Figure1b). Multiple batch feeding quantities were generally more variable than those in single batch. Actual catfish
biomass will be compared with inventories estimated with five different feed response methods utilized by industry advisors.
An inventory estimation error will be calculated for each.