Search USGS⌕ Search
Home/Archive/USGS

USGS · 1014372

Effect of dietary moisture level on response to diet by Atlantic salmon

S. G. Hughes
View original source ↗Export metadata ↓

Abstract

The addition of moisture (water) to a diet had no positive effect on the weight gain of fingerlings of Atlantic salmon ( Salmo salar ). Moisture additions up to 30% actually reduced weight gain by up to 10%. Diet moisture level is not the primary factor in the acceptability of some moist and semimoist rations by Atlantic salmon or in the growth of these fish.

Explore related subjects

Progressive Fish-CulturistArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S. G. Hughes. 1989. Effect of dietary moisture level on response to diet by Atlantic salmon. https://doi.org/10.1577/1548-8640(1989)051%253c0020%3Aeodmlo%253e2.3.co%3B2

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2000

Effects of rearing density and raceway conformation on growth, food conversion, and survival of juvenile spring chinook salmon

Four brood years of juvenile spring chinook salmon Oncorhynchus tshawytscha were reared in conventional and baffled raceways at various rearing densities and loads at Willamette Hatchery, Oregon. A period of rapid linear growth occurred from August to November, but there was little or no growth from November to March when the fish were released. Both fall and winter growth rates were inversely related to rearing density. Final weight and length were also inversely related to rearing density. No significant relationship between load and any growth variable was observed. Fish reared at lower densities in conventional raceways tended to develop bimodal length distributions in winter and early spring. Fish reared in conventional raceways showed significantly larger growth rates and final lengths and weights than those reared in baffled raceways. Food conversions and average delivery times for feed were significantly greater in baffled than in conventional raceways. No significant relationships were observed between either rearing density or load and condition factor, food conversion, or mortality. Mortality was not significantly different between the two raceway types. When fish were transported to seawater for further rearing, there were no significant relationships between mortality in seawater and rearing density or load, but fish reared in baffled raceways had significantly higher mortality than those reared in conventional raceways.

Progressive Fish-Culturist↗
USGS1998

Effects of immobilization by electricity and MS-222 on brown trout broodstock and their progeny

To determine the effects of electrically and chemically induced immobilization on postspawn broodstock and their progeny, age‐2 and age‐3 female broodstock and age‐2 male broodstock of brown trout Salmo trutta were immobilized with electricity or tricaine methanesulfonate (MS‐222), stripped of their eggs or milt, and weighed. Eggs taken from electrically immobilized females were fertilized with milt taken from age‐2 males that were immobilized with electricity, and eggs taken from females immobilized with MS‐222 were fertilized with milt taken from age‐2 males that were immobilized with MS‐222. After spawning, the mortality and weight of broodstock were compared twice over a 6‐month period. Egg viability and growth of offspring fry from each treatment group were also compared. Electricity induced complete and consistent immobilization in brown trout broodstock. Electrically immobilized fish were more easily handled than fish immobilized with MS‐222; however, electrically immobilized fish survival (70%) was significantly less than fish immobilized with MS‐222 (83%). Broodstock growth differences were only noted at 6 months postexposure, when the mean weight of electrically immobilized fish was slightly less than the weight of fish immobilized with MS‐222. Broodstock immobilization by electricity did not reduce egg viability or fry growth.

Progressive Fish-Culturist↗
USGS1998

Effects of routine handling and tagging procedures on physiological stress responses in juvenile chinook salmon

Juvenile chinook salmon Oncorhynchus tshawytscha were subjected to handling and tagging protocols typical of normal hatchery operations and monitored for their physiological response to stress. Treatments included coded‐wire‐tagging, counting, ventral fin clipping, adipose fin clipping, and a procedure simulating a pond split. Treatment fish were also subjected to a standardized stress challenge (1 h confinement) to evaluate their ability to deal with disturbances subsequent to a handling or tagging procedure. Circulating levels of cortisol and glucose were used as indicators of stress. Each of the treatments elicited very similar responses among treatment groups. Cortisol increased from resting levels of about 20 ng/mL to about 90 ng/mL by 1 h poststress and returned to near resting levels by 8 h poststress. Glucose levels increased from 50 mg/dL to about 80 mg/dL by 1 h poststress and remained elevated for much of the experiment. The cortisol and glucose responses to the confinement stress did not differ over time or among treatments. However, the confinement stress results do suggest a small but significant cumulative response, indicating small residual effects of the original handling protocols. No deaths were noted among treatment groups.

Progressive Fish-Culturist↗