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W. F. Krise

Publications and source records attributed to W. F. Krise.

36 records · Page 2Linked to original sources
USGS1991

Resistance of underyearling and yearling Atlantic salmon and lake trout to supersaturation with air

Juvenile Atlantic salmon Salmo salar and lake trout Salvelinus namaycush of different sizes were exposed for 96 h to water supersaturated with air. Underyearlings (Atlantic salmon shorter than 66 ± 8 mm [mean total length ± SD] and lake trout shorter than 96 mm) were resistant to high dissolved-gas pressures. The level of supersaturation causing 50% mortality was lower for yearling Atlantic salmon (148 ± 17 mm long) than for underyearling Atlantic salmon, and sensitivity to supersaturation was greater in lake trout 96 ± 1 to 153 ± 17 mm long than in those 23 ± 1 to 46 ± 4 mm long. Incidence of cutaneous emphysema and other signs of gas bubble disease increased as supersaturation increased. The number of bubbles and number of sites with bubbles were higher in the older fish. Among fish 150 ± 17 mm long, Atlantic salmon seemed to be less resistant to gas supersaturation than did lake trout.

Journal of Aquatic Animal Health↗
USGS1991

Tolerance of subyearling American shad to short-term exposure to gas supersaturation

Subyearling American shad Alosa sapidissima normally migrate from rivers in the fall and may encounter changes in gas supersaturation levels while traversing hydroelectric dams. To determine whether changes in behavior or survival occur during these events, we exposed subyearling American shad to five levels of gas supersaturation that included pressure increases above equilibrium (▵P) from 10 to 205 mm Hg (101–128% saturation) for 4 h. Multifactor analysis of variance showed no significant differences in behavior or survival of fish before or after treatment. Gas bubbles were observed on external tissues of fish only at the highest treatment level (▵P = 205 mm Hg). Factor analysis elucidated three categories of behavioral organization under experimental conditions: boundary, social, and nonsocial behavior. Under gas supersaturation conditions thought to occur in dammed rivers of the eastern USA, the behavior of subyearling American shad does not appear to be affected in a way that might reduce survival during migration.

North American Journal of Fisheries Management↗
USGS1990

Effect of feeding rate and gas supersaturation on survival and growth of lake trout

Fingerling lake trout ( Salvelinus namaycush ) were reared for 35 d in water with total dissolved gas pressures of 46, 78, 108, or 159 mm Hg above ambient conditions (▵P). Within each gas pressure treatment, daily feeding rations were (1) 1.7% of the total weight offish in the heaviest of three replicates, (2) 1.7% of the weight of fish in each individual tank, or (3) 0.9% of the weight in each tank (underfeeding). Signs of gas bubble trauma were first observed as hemorrhagic spots on the eyes of some fish reared at ▵P = 46, and external evidence of trauma increased as ▵P increased. All fish sampled at ▵P = 159 showed signs of gas bubble disease; the most common were eye hemorrhage and bubble formation inside the mouth. Mortality was 11% or less among fish reared at gas levels up to ▵P = 108. Mortality was as high as 55% at ▵P = 159, but did not differ among feeding treatments. Net weight gain by fish was low at ▵P = 159 because of both high mortality and slow growth. Growth was slowest for underfed fish at all gas levels, and underfed fish consistently showed increasing injury as gas pressures increased. Calculation of feeding rate on the basis of fish weight in individual tanks allowed the most cost‐efficient food distribution. Culture of lake trout at ▵P < 46 is recommended.

Progressive Fish-Culturist↗
USGS1990

Adverse effects of heated Bouin's solution on fish preservation

Rainbow trout Oncorhynchus mykiss (formerly Salmo gairdneri ) and lake trout Salvelinus namaycush preserved by immersion in Bouin's solution at 48°C became severely deformed due to muscle contraction. This was reflected in tissue changes, indicating that this technique induces undesirable artifacts that are likely to interfere with histological examination.

Journal of Aquatic Animal Health↗
USGS1988

Optimum protease exposure time for removing adhesiveness of walleye eggs

Increasing concentrations of protease solution reduce the treatment time required for removal of the adhesive layer surrounding eggs of the walleye ( Stizostedion vitreum ). When concentrations were increased from 0.01 to 0.1%, treatment time decreased from 30 to 5 min; however, treatment with a 1.0% solution for more than 1 min resulted in 100% egg mortality.

Progressive Fish-Culturist↗
USGS1987

Growth and survival of fingerling lake trout reared at four densities

Fingerling lake trout (Salvelinus namaycush) were reared at density indexes (fish density, in pounds per cubic foot, divided by fish length in inches) of 0.25, 0.50, 1.0, and 2.0. Final lengths, weights, condition factors, and mortality rates did not differ among the treatments. We conclude that fingerling lake trout may be successfully reared at a density index of at least 2.0 if water requirements for respiration and waste dilution are met. Our results indicate that fish length may be less important in determining allowable fish densities than was previously suspected.

Progressive Fish-Culturist↗
USGS1986

Effects of rearing density on growth and survival of lake trout

Lake trout (Salvelinus namaycush) were reared at density indices (allowable density in pounds/cubic foot divided by fish length in inches) of 0.25, 0.50, 1.0, and 2.0 in cages suspended in circular tanks. Water flow rates were such that dissolved oxygen remained above 8 ppm within all the cages. Thus treatment effects were attributed to density and not influenced by water quality. Growth and condition were not affected by density, but survival was lower at the higher density than at the three lower densities. We conclude that lake trout may be successfully reared at a density index of at least 1.0 if the water requirements for respiration and waste dilution are met.

Progressive Fish-Culturist↗
USGS1986

Review of the intensive culture of walleye fry

Efficient intensive culture of larval walleyes (Stizostedion vitreum) may soon be realized due to results of research on larval development, culture environment, preferred food organisms, and feeding techniques. Larval behavior and morphology (developmental state) can be used as indicators for appropriate handling and feeding techniques. Certain environmental conditions such as a rearing unit color that contrasts with food organisms, water temperatures of 18‐22°C, uniform lighting, and a stocking density of no more than 35,000 fish/m 3 reportedly contribute to increased growth and survival. Successful culture requires that suitable food such as cladocerans, copepods, and brine shrimp be continuously available at a high density (0.1 organism/mL). Cannibalism among walleye larvae has not been prevented but has been reduced through the use of suitable fish and food densities.

Progressive Fish-Culturist↗
USGS1986

Increased walleye egg hatch and larval survival after protease treatment of eggs

Various techniques for eliminating the clumping of newly spawned walleye eggs (Stizostedion vitreum) were evaluated by measuring hatch, growth, and survival. Percent hatch was highest (83%) in egg groups water hardened in 0.01% protease solution. Other water‐hardening techniques tested were: (1) continuous stirring; (2) 250 mg/L tannic acid solution; and (3) bentonite clay suspension. Low hatching percentages for eggs continuously stirred or treated with bentonite were attributed to fungus. Fungus was minimal on eggs treated with protease or tannic acid. Fish hatched from each egg treatment group were intensively cultured for 21 d in one of four rearing environments: (1) well water; (2) well water receiving 1% sea salt for the initial 3 d; (3) well water receiving a 6‐mL daily addition of antifoam emulsion for the initial 9 d; or (4) well water receiving both the 1% sea salt and antifoam treatments. There was slightly higher survival in larval fish hatched from eggs treated with protease or tannic acid and reared in well water containing 1% sea salt. We observed no differences in average fish length among the test groups.

Progressive Fish-Culturist↗
USGS1983

Effect of temperature on production of tiger muskellunge in intensive culture

Tiger muskellunge ( Esox masquinony × E. lucius ) juveniles were reared at constant temperatures in the temperature range 14–28°C. For fish 3–4 cm long, growth, production and feed conversion efficiency were greatest at 20–22°C. Survival was reduced and unaccountable mortality (cannibalism index) was greatest at 24°C. Growth per unit of temperature was about equal over the range 16–22°C. For fish 12–13 cm long, feed conversion efficiency and mean individual growth were greatest at 23°C; growth per unit of temperature was nearly equal over the range 20–24°C.

Aquaculture↗