Completion of  the Evaluation of  Effects of New Aerial Herbicides on Phytoplankton and Zooplankton and Water Quality in Fish Ponds
Peter Perschbacher, and Gerald Ludwig

The herbicides Aim (carfentrazone), Valor (flumioxazin), Dual (metolachlor), Liberty (glufosinate), Resource (fumiclorac), Major (flumioxazin) and Callisto (mesotrione) were evaluated in 2006 and only Aim produced moderate (5-30%) reductions in zooplankton. This completes the set of new herbicides. This study is the culmination of 10 years of evaluation of 39 herbicides. In addition to Aim the only impacts noted were with diuron. 

Paddlefish in Combination with Water Circulator Effects on Phytoplankton in Experimental Catfish Production Ponds.
Bart Green and Peter Perschbacher

Fingerling paddlefish were stocked at 16/acre in 0.025 acre ponds in which either a Solar Bee^tm upweller or slow paddlewheel water circulator was installed and in control ponds with no circulators. Phytoplankton were sampled bimonthly from March through October and composition was determined. The major groups were diatoms and cyanobacteria. Although mean counts by group did not differ, Anabaena circinalis was present May to mid-August in control ponds and July to mid-August in circulated ponds. And off-flavor species of cyanobacteria were present on 11 of 12 sample dates in control ponds and in 8 and 7 of 12 dates in circulated ponds. Results are being further analyzed. 

Effect of Winter Feeding and No Feeding of Channel Catfish on Phytoplankton Composition in Experimental Ponds.
Peter Perschbacher and Adam Nanninga

Phytoplankton samples were taken at weekly intervals and composition determined during a winter production experiment with standard winter feeding compared to no feeding. Results are being analyzed. 

Effect of Varying Levels of Winter Feeding on Water Quality, Plankton Composition and Benthos on Four Channel Catfish Commercial Farms
Peter Perschbacher, Gerald Ludwig and Martin Matute

Sampling for plankton and water quality was started in late December on a weekly basis in 3 commercial catfish ponds on each of four farms with differing feeding practices during the winter. Benthic samples were taken on a monthly basis and examined for possible overwintering, off-flavor algae “spores”. Sampling will continue into May and then monthly through the summer. Weekly sampling will resume in November, 2007. Results are being analyzed.