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

EVALUATION OF DIFFERENT ORGANIC FERTILIZERS AND STOCKING GRADED
JUVENILES AS MANAGEMENT PRACTICES FOR LOW INPUT PRODUCTION OF
FRESHWATER PRAWNS Macrobrachium rosenbergii IN EARTHEN PONDS
Louis R. D’Abramo* and Terrill R. Hanson
Department of Wildlife and Fisheries
Mississippi State University
Box 9690
Mississippi State University
Ldabramo@cfr.msstate.edu
Juvenile freshwater prawns were stocked at a density of 24,100/ha into 0.05 hectare earthen ponds that two weeks prior had
been fertilized with a one time application of cottonseed meal at 224.2 kg/ha followed by additions of 16.8 kg/ha every other
day. There were five treatments, five replicates (ponds) per treatment. All ponds contained vertically orientated substrate (orange
plastic fencing) supplied at a rate of 25 % of the bottom surface area. One group of three treatments were designed to compare
the efficacy of the different organic fertilizers, range cubes, alfalfa pellets, and soy hull pellets, using ungraded juveniles
with a mean stocking weight of 0.215 g. The effect of stocking ungraded juveniles (mean weight = 0.215 g) versus juveniles
from the same population graded into two groups (mean weight 0.275 g and 0.123 g) was also evaluated using another group
of three treatments in which ponds were fertilized with range cubes. The total amount of organic fertilizer applied to all ponds
for the entire growing season (128 days) was calculated based on a 3:1 ratio of fertilizer to anticipated yield at harvest. Daily
application rates of the organic fertilizers ranged from 13.1 to 33.6 kg/ha/day and were calculated from proportions of the total
amount assigned to different time intervals (weeks) during the growing season. The effects of fertilizer type and grading on
survival, mean harvest weight, and total production, and the results of a corresponding economic analysis will be presented.