| Abstrakt: |
Techniques were developed to rear larval walleyes (Stizostedion vitreum) successfully through the first 30 d, the current bottleneck in the intensive culture of this species. Fish were reared at production densities of 60 fish/L at two temperatures, 19 and 24°C. Upwelling water flow with frequent food provision maintained food particle densities close to 100/L. Fish were fed entirely on a new experimental diet, Kyowa Fry Feed (Kyowa Hakko Kogyo Co., St. Louis), offered in graded particle sizes appropriate for larval walleyes. This diet was readily ingested by larvae from the first day of feeding. At 19°C, mean survival to 30 d was 28%, and final total lengths were 23.4 mm. Fish reared at 24°C grew to 31.4 mm, but a single catastrophic decrease in dissolved oxygen caused large losses, and final survival in this group was only 4%. Further modifications of this culture system will be needed to improve water quality and facilitate swim bladder inflation. [ABSTRACT FROM PUBLISHER] |
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