Fish . Hatchery. Amy . Doll . 1. , . Casey Williams . 1. , Kurt . Eversman . 2. , David Demuth. 3. ; . 1. Department . of Science, Valley City State University, Valley City, ND 58072; . 2. US Fish and Wildlife Service Valley City National Fish Hatchery, Valley City, ND . ID: 749900
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Stocking Density, Walleye Survival, and Zooplankton Communities at Baldhill National
Fish HatcheryAmy Doll 1, Casey Williams 1, Kurt Eversman 2, David Demuth3; 1Department of Science, Valley City State University, Valley City, ND 58072; 2US Fish and Wildlife Service Valley City National Fish Hatchery, Valley City, ND 58072, 3 Great Plains STEM Education and Research Center, Valley City State University, Valley City, ND 58072
Fry were stocked in six ponds (Figure 1) at three stocking rates on June 3, 2013200,000 fish/surface acre (FPSA) – Ponds 2 and 5250,000 fish/surface acre – Ponds 6 and 9300,000 fish/surface acre – Ponds 13 and 14Harvested between June 24th and June 26thPercent survival of walleye stocking densities were arcsine transformed and analyzed with 1 Factor Analysis of Variance (ANOVA; α = 0.05). Tukey’s test (α = 0.05) were used for pairwise comparisons.Ponds were normally fertilized twice a week.Zooplankton Sampled on Mondays and Thursdays during June.Split into manageable sample size using a Folsom plankton splitterCounted and identified using a Ward Counting Wheel. Categorized into five groups: rotifers, cyclopoids, calanoids, nauplii, and cladocerans
This study was conducted to examine juvenile walleye Sander vitreus fry survivorship at three stocking densities in ponds at Baldhill National Fish Hatchery.Walleye survival rates were correlated with temporal patterns in zooplankton populations to examine possible interspecific regulation of walleye abundance and survival.
Compared to higher stocking rates, stocking walleye fry at 200,000 fish per surface acre results in the highest survivorship; thus, the lower stocking density should be used to maximize walleye production at Baldhill National Fish Hatchery (Figure 4).Current fertilization rates appear to promote adequate zooplankton communities to support walleye production at Baldhill National Fish Hatchery.
Figure 3. Temporal plankton density in
Baldhill National Fish Hatchery ponds stocked with walleye fry at three stocking densities.
Figure 1. Aerial view of Baldhill National Fish Hatchery
Figure 2. Percent survivorship for three stocking rates of walleye fry at
National Fish Hatchery. Letter designations (A, B) represent statistical significance (
= 0.05) between stocking rates.
} 200,000 FPSA
} 250,000 FPSA
} 300,000 FPSA
Walleye percent survivorship was significantly higher (P < 0.05) when stocked at 200,000 FPSA (mean = 47.5%, SD =0.7) than 300,000 FPSA (mean = 25.5%, SD =6.4; Figure 2).
Although not statistically significant (P >0.05), walleye survivorship was higher when stocked at 200,000 FPSA than when stocked at 250,000 FPSA (mean = 33%, SD = 1.4).
Similar trends in zooplankton abundance across ponds suggests zooplankton abundance is not a limiting factor between different stocking rates (Figure 3).
4. Mean number of fish produced per surface acre for three stocking densities at
National Fish Hatchery.
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