摘要:

A thermistor probe was used to study deep (white) muscle temperature of five species of freshwater fishes at rest as well as that of exercising and resting trout. The resting deep muscle temperatures were 0.1 to 1.1 C higher than the water temperature. In exercising trout, temperatures of the deep muscle were the same as the temperature of the water.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<709:TOTIFF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Young-of-the-year hatchery reared rainbow trout, Salmo gairdneri, were used to estimate the rate of gastric evacuation of meals of oligochaetes and commercial pellets at water temperatures of 5, 10, 15, and 20 C. Different regression models produced different predictions for 25, 50, and 100% stomach emptying times for pellet meals consumed at 15 C. Greatest variation occurred when predicting time required for 100% stomach evacuation. Estimates ranged from 22 to 35 h for a substantial 13-h difference. Because the semilog model consistantly produced the highest F regression and the lowest F deviation it was selected as best for describing the data. Rate of gastric evacuation increased with increased temperature. Differences were greatest between 0 and 5 C and least between 15 and 20 C. An increase of 5 C at the low end of the temperature range produced a much greater absolute effect than at the high range. Depending on food type, it took 3 to 4 times as long to empty the stomach by 50% or 100% at 5 C as it did at 20 C. Time to empty the stomach increased from a minimum of 16.4 h at 20 C for both foods to 58.5 h and 72.4 h at 5 C for oligochaetes and pellets, respectively.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<712:TAROGE>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Throughout the growing season, from March to October, marked fish usually made a daily trip to the feeding station. In the spring, they did not use the demand feeders until temperatures reached 12 C and they stopped demand feeding in the fall at approximately 22 C. In the spring, intermittent feeding appeared to be primarily temperature related. At cold temperatures fish did not feed daily. After the water had warmed to 22 C fish fed on a daily basis. During summer, low oxygen concentrations often caused fish to adjust or miss their daily feeding period. Feeding was reduced at oxygen values below 5 mg/liter, but fish occasionally fed at values as low as 3 mg/liter.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<718:SFITFB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Three distinct behavior patterns were recognized in the daily routine of channel catfish (Ictalurus punctatus) in culture ponds: (1) occupancy of home areas; (2) daily trip to the feeding station; and (3) feeding. When the fish were not in home areas they were going to or from the feeding station by specific routes or swimways. The pond bottom in home areas and swimways was hard and free from silt while the remainder of the pond bottom had a layer of soft mud and silt. Ponds stocked with similar size fish had fewer and larger home areas, and fewer but wider swimways, than ponds stocked with mixed sizes. In the spring and fall, home areas and swimways were in shallows but during summer and winter they were in deeper parts of the pond.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<725:HAASIC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

摘要:

Tannin has been used to decrease adhesiveness of walleye (Stizostedion vitreum) eggs for the purpose of shortening the water-hardening phase of walleye propagation. In this study, adhesiveness of fertilized walleye eggs decreased after exposure to tannin concentrations between 200 and 1,000 mg/liter. Reduction in adhesiveness was generally proportional to tannin concentration and exposure time. Adhesiveness was further reduced and eliminated in higher tannin concentrations by stirring the eggs during a 2-minute exposure. Hatching success of nontreated (control) eggs averaged 37 and 47 percent whereas hatching success of tannin-treated eggs averaged 38 and 50 percent for 1974 and 1975, respectively.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1976)105<731:TAAATE>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1976.10493025

出版商:Taylor & Francis Group    

年代:1976

数据来源: Taylor