摘要:

In vitro and in vivo efficacy of a potentiated sulffonamide, Ro5–0037, for inhibition ofAeromonas salmonicida, causative agent of fish furunculosis was determined. The components of the potentiated sulfonamide, sulfadimethoxine, and ormetoprim were tested alone and in combination. In vitro results showed that both sulfonamide-resistant and sensitive strains ofA.salmonicidahad greater sensitivity to Ro5–0037 than to either of its components. Also, sulfonamide-sensitive strains developed resistance to ormetoprim and sulfadimethoxine more rapidly than to Ro5–0037. Efficacy studies with small numbers of artificially infected trout revealed that Ro5–0037 effectively controlled furunculosis at 50 mg/kg of fish/day, one fourth the usual sulfonamide dosage level. Extensive field trials also showed the 50 mg/kg level of Ro5–0037 gave effective control of hatchery outbreaks of furunculosis. As found in the in vitro studies, all in vivo trials indicated the combination of ormetoprim and sulfadimethoxine was more efficient in inhibitingA.salmonicidathan either component alone.

ISSN:0706-652X    

DOI:10.1139/f74-011

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Chum salmon fry (Oncorhynchus keta) in the estuary of a small coastal stream exploited fresh water, estuarine, and marine food chains and, by so doing, were exposed to marked, daily fluctuations in salinity that demanded active selection of fresh water on ebbing tides day and night. The resulting delay in seaward migration and associated behavioral observations are inadequately reflected in published accounts of the life history and behavior of chum fry in natural systems and laboratory situations, and the downstream displacement theory. The biological basis for delayed seaward migration of chum fry merits the attention of fishery researchers and resource managers alike.

ISSN:0706-652X    

DOI:10.1139/f74-012

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f74-013

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Oysters (Crassostrea virginica) showed positive growth response when fed artificial diets of known nutrient composition; differences in growth rate, meat weights, and glycogen content corresponded with differences in dietary composition. High levels of dietary carbohydrate resulted in greater oyster glycogen production. The type and level of lipid in the diet was also important. Cod liver oil was of higher nutritional value for the oysters than corn oil; increasing the dietary lipid from 5 to 18% of the dry weight, resulted in greater meat production and earlier total weight gains considered to be associated with earlier gonadal ripening.Oysters held in Malpeque Bay in floating trays grew 10 times faster than those held in tanks of continuously flowing filtered sea water and fed artificial diets.

ISSN:0706-652X    

DOI:10.1139/f74-014

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Yearling lake trout (Salvelinus namaycush) were anesthetized with a 150 ppm solution of M.S. 222 for 2 min at 10 C. When tested in a vertical temperature gradient, their behavior was abnormal for 5 days following anesthetization. Initially, they remained at the bottom of the gradient tank, as much as 63% of the time, and when they did swim up into the gradient, their temperature selection was much less precise than that of control fish. The percentage of fish on the bottom declined daily, and on the 6th day their temperature distribution did not differ from that of controls.

ISSN:0706-652X    

DOI:10.1139/f74-015

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Ozobranchus margoiis recorded from North America for the first time, as an ectoparasite of the marine turtlesChelonia mydas mydas,Caretta caretta caretta,Eretomochelys imbricata imbricata, andLepidochelys kempii. The pathology and treatment of the leech infestation are described and the presumed distribution of the species compared with that ofOzobranchus branchiatus, the only species of the genus previously recorded from North America.

ISSN:0706-652X    

DOI:10.1139/f74-016

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The B″ subunit of lactate dehydrogenase from the liver tissue of wild populations of resident rainbow trout (Salmo gairdneri) from the Loon and Pennask Lake areas has been found in a frequency of 0.400–0.800. An electrophoretically identical subunit was found in similar proportions in anadromous steelhead trout from the Thompson River, and from the Coquihala River in considerably smaller proportions. Steelhead from some coastal streams in and near Vancouver and Vancouver Island, and other selected streams from the Fraser and Skeena river systems generally revealed a very low frequency of less than 0.1.

ISSN:0706-652X    

DOI:10.1139/f74-017

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Five species of aquatic insects — two plecopterans, two trichopterans, and one ephemeropteran — usually found in streams or ponds were collected in water 32–100 m deep in western Lake Superior. All appear to be new records for the lake and all were collected from far greater depths than previously recorded for these forms.

ISSN:0706-652X    

DOI:10.1139/f74-018

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

When fresh fish muscle (Ophiodon elongatus) was exposed to free fatty acids (safflower oil hydrolysate), the whole myofibril lost its suspensibility more readily than its component proteins lost their solubility. SDS-acrylamide gel electrophoresis indicated that tropomyosin was the most readily insolubilized protein. In the presence of 0.04% formaldehyde, effects of the free fatty acids were increased approximately threefold.

ISSN:0706-652X    

DOI:10.1139/f74-019

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

A method of extracting oil is described in which ether is used as the lipophylic solvent in a monophase system. The method is as effective as the Bligh and Dyer method of extraction and avoids the use of chloroform, which interferes when gas chromatography is used with electron capture detection for analysis of the volatiles.

ISSN:0706-652X    

DOI:10.1139/f74-020

出版商:NRC Research Press    

年代:1974

数据来源: NRC