Production and Flow Cytometric Identification of Triploid Walleyes

Triploid induction experiments were conducted on fertilized walleye (Stizostedion vitreum) eggs in 1987 and 1988. Different methods and different heat-shock treatment regimes were used between years; either the water temperature, initiation time, or the duration of the heat shock were varied. In 1987, three replicates of four treatments were conducted: 3SoC-10 min after fertilization (MAF)-1. 0 min, 3SoC-10 MAF-2.0 min, 400C-10 MAF-1.5 min, and 120C-10 MAF-1.5 min (control treatment). The heat-shock treatments of 3SoC-10 MAF-2.0min and 400C-10 MAF-1.5 min were lethal to walleye eggs acclimated to 120C. Total percent hatch for the treatments of 380C-lo MAF-1. O min and 12oC-10 MAF-1.5 min was estimated to be 37.7% and 36.9%, respectively. Walleye fry from these two treatments were stocked into 0.1 hectare hatchery rearing ponds in an attempt to rear them to the fingerling size. No walleyes survived to a size that would allow blood sampling, therefore no triploid assessment was made. In 1988, six heat-shock treatments and three control treatments were conducted The water temperature of the heat shocks was 29oC or 31 CC, the initiation times were either 1, 3, or 5 MAF, and all heat shocks 1mted for 25 min. Control treatmen1s had the same initiation time and duration regimes, but the water temperature was I <PC. Of the three replicates of the nine treatments that were conducted, two were not used in data calculations because fungal growth induced I 00% mortality in all but one treatment. Triploidy was produced by four of the six heat-shock treatments: 29oC-l MAF-25 min (20%), 3IoC-l MAF-25 min (100%), 3loC-3 MAF-25 min (92%), and 3loC-5 MAF-25min (75%). Diploid/tetraploidmosaicism was observed at a rate of 5% with a heat shock of 3 loC-5 MAF-25 min. Survival to the eyed stage of development and triploid yield of eyed eggs were highest with the heat-shock treatment of 31 oC-3 MAF-25 min. Diploid, triploid, and diploid/tetraploid mosaic walleye fry were stocked into a 0.05 hectare pond Growth and survival were monitored for a 90 d period. There was no difference in the mean total lengths of diploid (6.9 mm, n=98) and triploid (7.0 mm, n=50) walleyes at 1-2 d post-hatch. No diploid/tetraploid mosaics were recovered after 90 d, but diploid and triploid walleyes were removed from the pond. A single triploid walleye survived; its total length (79.0 mm) and wet weight (3. 7 g) were less than the surviving diploid walleye mean total lengths (101.6 mm, n=31) and mean wet weights (10.1 g, n= 31 ). Flow cytometric methods for identifying polyploid fishes were established and refined. Methods for processing fresh blood cells, blood cells fixed in 70% ethanol, and dissociated whole body tissues from larvae (fresh or fixed in 70% ethanol) were evaluated In addition, a two-step acridine orange staining protocol was successfully modified to provide an alternative method for use in fluorescent staining fish cell suspensions for flow cytometry.

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis - University Access Only

Discipline thesis:degree_discipline

Wildlife and Fisheries Science

Year

1989

Author dc:creator

• Ewing, Rebecca R.

Contributors dc:contributor

• Charles G. Scalet

• walleyes
• growth
• eggs
• population
• south dakota
• habitat
• Natural Resources and Conservation

Statement dc:rights

• Copyright © 1989 Rebecca Ewing

Language dc:language

en

Repository record dc:identifier

https://openprairie.sdstate.edu/etd/347

OAI identifier oai:identifier

oai:openprairie.sdstate.edu:etd-1347