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D. V. Rottiers

Publications and source records attributed to D. V. Rottiers.

12 recordsLinked to original sources
USGS1992

Effects of day length and cleaning regimen on the growth of yearling parr Atlantic salmon

Yearling Atlantic salmon ( Salmo salar ) were reared with 8 or 16 h of light each day in laboratory tanks that were cleaned daily or weekly, and growth was measured weekly for 10 weeks. Growth was greatest for fish on the 16‐h light and weekly cleaning routine. Reduced frequency of tank cleaning (weekly) significantly enhanced growth but accounted for only 8.5% of the partitioned variance, compared with 78.9% for increases in day length alone. Results of this study suggest that the increased growth observed at longer day lengths was primarily due to the stimulatory effects of increased amounts of light.

Progressive Fish-Culturist↗
USGS1991

Towable cage for studies of smoltification in Atlantic salmon

The floating towable cage described in this report was used successfully to hold and transport Atlantic salmon ( Salmo salar ) in estuarine waters. These rugged and versatile cages, constructed from readily available, inexpensive materials, were tied singly and in clusters to floating docks in fresh and brackish water, where they withstood strong currents, winds, floods, and tides for 2.5 months without visible damage.

Progressive Fish-Culturist↗
USGS1988

Lack of dietary effects on the timing of smoltification in Atlantic salmon

Six commercially available diets varying in lipid, protein, water, ash, and carbohydrate contents were fed to Atlantic salmon ( Salmo salar ) for 2 years to determine if diet affected smoltification. Each month, from March to September of the second year, sampled fish were exposed to 33‰ seawater for 24 h to determine smolt readiness, defined as the ability to maintain water and salt balance in a seawater challenge. Regardless of diet, Atlantic salmon were able to regulate plasma sodium and chloride ions (smoltify) only during early May. It is unlikely that hatchery managers could effectively use high‐energy diets to control the time of smoltification in Atlantic salmon.

Progressive Fish-Culturist↗
USGS1986

Growth of tiger muskellunge fed different amounts of protein at three water temperatures

Growth rates of tiger muskellunge (muskellunge Esox masquinongy ♀ x northern pike E. lucius ♂) fed diets containing 35, 45, or 55% crude protein for 5 weeks at 17, 20, or 23°C were compared. Fish fed diets containing 45 or 55% protein grew faster at all temperatures than those fed 35% protein. Growth of tiger muskellunge fed a diet containing either 45 or 55% protein did not increase significantly at optimum growth temperatures (20 or 23°C). At 17°C, below the optimum temperature range, growth did increase when the percentage of protein in the diet was increased.

Progressive Fish-Culturist↗
USGS1985

Movement of underyearling walleyes in response to odor and visual cues

Underyearling walleyes, allowed to move freely in a Y‐shaped chamber into which various substances were added to one arm or another, were attracted to sodium chloride, sucrose, glutathione, vitamin B 12 , betaine, arginine, Daphnia slurries, some fish slurries, washings from live Daphnia and Artemia, and some commercial fish foods. They avoided cysteine, glycine, glycine‐betaine, Artemia slurries, some fish slurries, and fish mucus; and showed little reaction to valeric and caproic acid, and some commercial fish foods. Tests of visual response, in which beakers containing live food organisms were placed in the arms of the chamber, indicated that walleyes respond strongly to the movement of food organisms. Walleyes usually surrounded the beakers containing live food organisms and repeatedly struck the glass. They were attracted more strongly to Artemia than to Daphnia. Results indicate that odor plays an important role in movement of walleyes to food and that there is a potential for attracting intensively cultured walleyes to man‐made diets with odorants.

Progressive Fish-Culturist↗
USGS1981

Comparative hatchability of lake trout eggs differing in contaminant burden and incubation conditions

In 1972, fertilized eggs of lake trout ( Salvelinus namaycush ) from the Marquette (Michigan) State Fish Hatchery (where levels of contaminants are relatively low) and eggs from lake trout collected in Michigan waters of Lake Michigan near Saugatuck and Charlevoix (where levels of PCB's and DDE are elevated) were incubated at hatchery temperatures (6° C) and at temperatures simulating the natural temperature cycle of Lake Michigan (1-8° C). Survival to yolk absorption of larvae from these three sources ranged from 40.3 to 65.5%, and no correlation was observed between survival and the level of PCB's and DDE in the eggs. Additional studies in 1975 with lake trout eggs from the same three sources confirmed previous observations that the elevated levels of PCB's and DDE in eggs from Lake Michigan did not appear to affect the percent hatch of lake trout eggs or survival of the fry to the swim-up stage. When fry hatched from eggs with an elevated contaminant burden were starved for several weeks, we observed no abnormal increase in posthatching mortality during the period when the yolk stores were being consumed.

Technical Paper↗