摘要:

The Lintzel method of trimethylamine oxide determination was found to give low results when less than 2 to 5 mg. oxide nitrogen was present. By suitable modification this could be reduced to 2 mg. above which a constant 96 per cent recovery was obtained. However, many fish extracts contain only 0.5 to 2 mg. nitrogen in the aliquot which can be used for the reduction.A modified Norris and Benoit procedure, which is much simpler to use, was developed. This gave about 96 per cent recovery down to about 0.4 mg. nitrogen. Extraction of the fish muscle with either trichloracetic acid or formaldehyde was satisfactory.

ISSN:0706-652X    

DOI:10.1139/f50-019

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Original determinations of the trimethylamine oxide content of 60 species of fish are recorded, and 21 additional species have been studied by others. Elasmobranchs have the highest content of oxide, two to five per cent based on dry weight. Among teleost fishes, the amount increases from the lower to the higher orders, freshwater fish containing no oxide. Analyses of several species of marine invertebrates confirm earlier work showing that certain molluscs, echinoderms and other organisms contain trimethylamine oxide, often in quantities similar to those in the higher teleosts.

ISSN:0706-652X    

DOI:10.1139/f50-020

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Study of the denaturation of cod muscle proteins by sodium chloride shows that the myosin fraction is denatured when a critical salt concentration, about 8 to 10 per cent in the muscle, is reached. Paralleling the rapid denaturation, a sudden increase of salt uptake and of moisture loss occurs.

ISSN:0706-652X    

DOI:10.1139/f50-021

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Extreme variations in temperature and salinity have been observed at depth, during the summer months, off North Rustico, P.E.I., and Cheticamp, N.S. These were correlated with wind force and direction, controlling factors of internal adjustment of water layers according to Ekman's theory of wind-driven currents.Organisms which cannot tolerate these sudden changes in temperatures and salinities will not form important groups in populations along the margins of the Magdalen Shallows.

ISSN:0706-652X    

DOI:10.1139/f50-022

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Coregonus clupeaformiswas taken in a small lake of southern New Brunswick. Although the species had not been known to occur in this region, this population is evidently indigenous. Fish of ages III–V were taken, the largest being 252 mm. in fork length.

ISSN:0706-652X    

DOI:10.1139/f50-023

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Maskinonge from three regions were studied: the Lake of the Woods district in Ontario (calledWestern); the Kawartha Lakes and Georgian Bay district in Ontario (Central) and the St. Lawrence River district in Quebec (Eastern). Examination of 202 stomachs, 81 containing food, showed the maskinonge to be a general carnivore, preying mainly on fish over 150 mm. in length. The families Percidae, Catostomidae, Ameiuridae, Centrarchidae, Hiodontidae, Esocidae and Cyprinidae were represented, along with at least oneCambarus. The yellow perch,Perca flavescens, was the species eaten most frequently in all three regions. A common white sucker (Catostomus commersonnii) was found in a stomach of the hybridE.masquinongy×E.lucius. Examination of the teeth of each specimen showed that they were being continuously replaced throughout the summer season.Rate of growth varied with sex and locality. Females had a significantly faster rate of growth, both in length and in weight, than did males. Maskinonge from the Western Region were shorter and weighed less than fish of the same age from the other two regions. Maskinonge of the Eastern and Central Regions reached the legal size of 30 inches fork length during their fifth summer, but in the Western Region they did not attain this size until their seventh summer. The length-weight relationship appears to be the same in the Eastern and Central Regions, whereas maskinonge from the Western Region tended to be heavier than those of comparable lengths from the other two regions. In all regions the length-weight relationship was a straight line when plotted logarithmically, its slope being estimated as 3.26 in the Eastern Region. Sexual maturity occurs first between the ages of three and six years, or about 575 to 800 mm. fork length. Specimens of aE.masquinongy×E.luciushybrid appeared to be infertile. They did not differ from the maskinonge specimens in their length-weight relationships but made faster growth than did the maskinonge from the same region.

ISSN:0706-652X    

DOI:10.1139/f50-024

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The effect of frequency of digging butter clams,Saxidomus giganteus, on production was tested by the Latin square method in five different localities of Southern British Columbia. Digging once in 7 years appeared somewhat less productive than digging every 1/2, 1, 2 or 3 years. Among the latter four frequencies there were no detectable differences.

ISSN:0706-652X    

DOI:10.1139/f50-025

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Recoveries of tags have provided limited information on the dispersion of several British Columbia groundfishes.Platichthys stellatusandHippoglossoides elassodonwere recovered mostly within 1 to 3 years and have moved less than 5 miles; however, oneP.stellatusshifted position by 60 miles in 51/2 years. A very few recoveries ofPsettichthys melanostictustags suggest that movements up to 25 miles may be not uncommon for this species.Anoplopoma fimbriarecoveries were nearly all within 10 miles of release but tagging was done under conditions favouring local recovery. During a year's freedom the average growth of a maleP.stellatusvaries from 35 mm. at 350 mm. initial size to 10 mm. at 520 mm.

ISSN:0706-652X    

DOI:10.1139/f50-026

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Hydrographic observations made incidental to summer patrol duties of the Royal Canadian Mounted Police vesselSt.Rocheshowed a relatively warm (6.5–8 °C.) saline (31.6‰) area in the Chukchi Sea, a cold (0.2–5.5 °C.) brackish (3–9‰) area from Point Barrow to Banks Island, and a cold (6.5–7.0 °C.) moderately saline (11.8–30.7‰) region from Banks Island through the channels to Coronation Gulf and Cambridge Bay.

ISSN:0706-652X    

DOI:10.1139/f50-027

出版商:NRC Research Press    

年代:1952

数据来源: NRC