The Effects of a Dairy/Yeast Prebiotic on Growth and Health of Goldfish (Cariassius auratus) in aquaria
Ruguang Chen, Harold Phillips, and Rebecca Lochmann

We conducted a feeding trial with goldfish in aquaria to determine whether practical diets supplemented with a dairy-yeast prebiotic, and 4- or 10% added poultry fat could improve fish performance or body composition. The basal formula was similar to a commercial diet (35% protein and 9.6 kg energy/gram of protein). Thirty fish (0.57+0.002 g in individual mass) were stocked into each of four replicate 110-L tanks per treatment in a recirculating system and fed twice daily to apparent satiation for 8 weeks. There were no differences in weight gain, survival or feed conversion among treatments. Whole-body lipid was higher in fish fed the 10% fat diets. Results of a bacterial challenge with Flavobacterium columnare were inconclusive, possibly due to low viability of the culture.

The Effects of a Dairy/Yeast Prebiotic on Growth and Health of Goldfish (Cariassius auratus) in outdoor pools
Ruguang Chen, Harold Phillips, and Rebecca Lochmann

Diets from the tank trial were also fed to groups of goldfish in outdoor pools to determine diet effects in the presence of natural foods. Four hundred(0.36 + 0.002g in individual mass) fish were randomly stocked into each of four plastic-lined 4.1-m³ pools containing reservoir water and maintained static during the study. Fish were fed twice daily to apparent satiation and group-weighed every 2 wks to track growth. Weight gain and condition factor improved with prebiotic in the 4% PF diet, or with a 10%-PF diet (with or without prebiotic). Whole-body lipid was higher in fish fed 10% PF versus 4% PF diets. Feed conversion and survival were similar for all diets. The prebiotic in the 4%-PF diet improved survival of goldfish challenged with F. columnare when the fish were stressed (crowding) before the challenge. The influence of natural foods in the pool study compared to the aquarium study were evident in the much higher growth rate of fish in pools. Nevertheless, diet differences were more pronounced in the pool trial than in the aquarium trial, indicating the potential for enhancing goldfish performance under production conditions.

Nutrient Management in Commercial Baitfish Ponds
Nathan Stone, Alex Kachowski and Hugh Thomforde  

As groundwater from wells is added to begin the filling of commercial baitfish ponds, processes within the ponds change the water chemistry. Typically, phosphorus concentrations decrease and dissolved inorganic nitrogen levels increase. A major objective of this work is to determine appropriate levels of nutrient inputs to initiate algal blooms in baitfish ponds, so the timing of algal bioassays relative to the start of pond filling could influence recommended rates. Algal bioassays were conducted twice at a 4- to 5-day interval in eight commercial baitfish ponds in Lonoke County, Arkansas. Well and pond waters were collected for analysis and algal bioassays were initiated within 24-48 hours after filling began and again on either the fourth or fifth day. In general, results of the first and second bioassays for each pond, as determined by chlorophyll a extraction, followed a similar pattern. Typically, maximum chlorophyll-a concentration was achieved when the total concentration (spike plus initial concentration in water) of phosphorus was 0.3-0.5 mg/L and of nitrogen was 4-5 mg/L. Initial pond water chlorophyll-a concentrations (mean + SD) were lower for the first set of bioassays (15 + 17 ug/L) as compared to the second set (42 + 35 ug/L). Chlorophyll-a concentrations decreased within those bioassays where the initial concentrations were high, i.e. in excess of 50 ug/L. Results indicate that the exact timing of an algal bioassay after pond filling commences is not a critical factor. Algal bioassays can be used to provide semi-quantitative estimates of nutrient requirements to initiate blooms, avoiding unnecessary or excessive applications of nutrients.

Developing Hatchery Management Techniques for Fathead Minnows
Ashlee Paver and Nathan Stone  

In order to intensify operations, golden shiner and goldfish farmers bring egged mats indoors and incubate the eggs in hatcheries. A similar technique might be useful for fathead minnows; major obstacles include identifying preferred substrates to collect eggs quickly and efficiently, and preventing losses to fungus during egg incubation.

Substrate preference - If fathead minnows would seek out and lay on specific substrates, these substrates could be used for egg collection. In the first study, fathead minnows preferentially laid more eggs on the flat substrates than they did the layered substrates. In the second study, hard substrates were tested against softer substrates; fathead minnows showed no preference for either substrate. The third study consisted of 3 trials: 1) egg mimics (glass beads) vs. plain (control) substrates, 2) egg mimics vs. small painted dots vs. plain, 3) and small painted dots vs. large painted dots vs. plain substrates. In trials 1 and 2, the fathead minnows strongly preferred substrates with the glass bead egg mimics. However, there was no preference among substrates with small painted dots, large painted dots, or plain black (control). Fathead minnow males are known to prefer nest sites that already contain eggs, and males will evict another male that is guarding eggs in order to claim the nest site. Flat substrates with clusters of egg mimics could be used to increase egg collection from fathead minnow brood ponds.

Fungus control - Three rates (500; 1,000; 1,500 mg/L) of two fungicides (formalin and hydrogen peroxide) and three water flow rates (35; 60; 85 mL/min) were tested for efficacy in controlling fungus during incubation of FHM eggs (rosy red variety). Treatments consisted of once daily, 15-min, flow-through applications of formalin or hydrogen peroxide (60 mL/min flow rate for all), or the three flow rates or control (60 mL/min), with 5 replicates each. All rates of the formalin and hydrogen peroxide treatments resulted in significantly greater hatching rates (70.4 – 81.7%) than the control (34.3%) or 60 and 85 mL/min flow rate treatments (42.0% and 33.3%, respectively). The hatching rate of FHM eggs in the slow flow rate (35 mL/min) treatment was comparable to that of eggs receiving daily chemical treatments. A once daily treatment combined with the slow flow rate provided the best results.

Golden Shiner Growth in Aquaria with Access to Fractions of Natural Foods  
Nathan Stone, Greg O’Neil, and Marcella Melandri  

Golden shiners in indoor systems exhibit relatively slow growth even when fed a complete diet. The cause is thought to be the lack of natural foods, although this has not been confirmed. A 4-week trial was conducted in an 18, 110-L aquaria system to determine the growth response of golden shiner juveniles to the presence of three size-fractions of natural foods. A 0.37-kW pump submerged in a fertilized earthen pond delivered water to the aquaria via a pressurized continuous loop of pipe. Pond water was filtered through 10- or 100-micron filters or not filtered (raw). Pressure-compensating orifices in the discharge pipe of each filter regulated flow and each aquarium received water at a nominal rate of 3.8 L/min. Each aquarium was stocked with 20 juvenile golden shiners (average weight of 0.04 g) and fish were fed once daily with a 42% crude protein commercial flake feed at a rate of 3% of their body weight. Weight gain of fish with access to larger zooplankton (no filter) was double that of fish in the 10-micron treatment and fish were in better condition. Overall mean concentrations of rotifers decreased from 398/L in the no filter treatment to 57/L and 12/L in the 100- and 10-micron treatments, respectively, and total zooplankton concentrations (excluding rotifers) followed a similar pattern. The growth rate of fish in this study was greater than that reported for indoor studies and comparable to that of similarly-sized fish cultured in earthen ponds, implying that lack of natural foods is responsible for the slow growth of golden shiners in indoor studies.

Effect of different management regimes on winter water quality and plankton in golden shiner commercial production ponds
Peter Perschbacher  

Sampling was begun on 4 golden shiner farms and in 3 ponds on each farm. Sampling regimes will follow that of the winter study of channel catfish farms and ponds. Two farms were chosen with low inputs and two farms with higher inputs, mainly of feed.

Preliminary results indicate lower plankton numbers and biomass in the low input ponds and higher variability. Emphasis will be on quantifying cyclopoid copepods to determine possible predation pressure on golden shiner fry.

 Evaluation of the effect of drift of a winter wheat herbicide on pond plankton and water quality
Peter Perschbacher  

On March 25 the aerially-applied winter wheat herbicide, thifensulfuron/tribenuron, was evaluated in the mesocosm facility at UAPB for possible effects on the water quality and plankton of fish ponds from drift. No effects were noted. This is the 40^th herbicide tested for drift effects on pond plankton and water quality and completes the study.