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ARS Home » Research » Publications at this Location » Publication #125634


item Pfeiffer, Tim
item Ludwig, Gerald

Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2002
Publication Date: 1/27/2002
Citation: Pfeiffer, T.J., Ludwig, G.M. 2002. Turbimetric numeric methods for estimating the density of a cultured rotifer population [abstract]. Book of Abstracts Aquaculture America. p. 264.

Interpretive Summary:

Technical Abstract: The objective of this research was to obtain a practical solution to estimate the number of individuals in a cultured rotifer population. Rotifers (Brachionus plicatilis) were cultured in translucent polyethylene tanks with a culture volume of 45-L. A hydrosponge filter was placed into each tank for biofiltration and collecting solids. Approximately 100 mL of feed solution was delivered every hour to the culture unit. The feed solution was a mixture of commercially available Nannochlorposis algal paste and salt water. Salt water for the feed solutions and culture tanks was maintained at 25 ppt and was produced with an artificial sea salt mix and filtered tap water. The rotifer population in each culture unit was maintained between 500 and 1500 rotifers per mL. A volume of fifteen liters was harvested when the estimated rotifer population was above 1500 rotifers per mL. Feed concentrations ranged from 25,000 to 150,000 algal cells per rotifer per day. Counts of rotifers were determined within a 1-mL Sedgewick Rafter counting cell with the use of an optical microscope. Resultant counts were extrapolated to determine the rotifer density in the tanks. Culture turbidity of the rotifer population was determined with a portable turbidimeter (HACH Model 2100P). The correlation indicated turbidity to be an affordable and practical solution for a rapid estimate of the rotifer population.