摘要:

Under laboratory conditionsBact.salmonicidamultiplies in unaltered domestic sewage and survives therein for 15 days. Removal, destruction or diminution of the original sewage flora resulted in marked multiplication ofB.salmonicidainocula, and in survival periods of from 13 to 67 days. Viability figures derived from laboratory procedures may not be directly applicable in interpreting the fate ofB.salmonicidareleased under natural conditions into natural waters.

ISSN:0706-652X    

DOI:10.1139/f40-002

出版商:NRC Research Press    

年代:1940

数据来源: NRC

摘要:

In spruce boards from July 6 to November 12 growth was as much as 24 cm. with, and 5 cm. across, the grain; fastest at high temperatures but continued even below 10 °C.

ISSN:0706-652X    

DOI:10.1139/f40-003

出版商:NRC Research Press    

年代:1940

数据来源: NRC

摘要:

Embryological development is followed over a period of ten weeks after hatching. The mode of formation of the components of the vertebral column is compared with that inClupea harengus, and is described in detail where differences are observed or additional information is available. Development appears essentially similar in the two species, although in general more rapid relative to length inC.pallasii. At hatching, myotome formation is complete and the ultimate vertebral number of an individual is presumably determined by that time. During ossification of the vertebral column, complex growth gradients from one or more centres are observed.

ISSN:0706-652X    

DOI:10.1139/f40-004

出版商:NRC Research Press    

年代:1940

数据来源: NRC

摘要:

Pteropod collections from several expeditions show bothClione limacinaandLimacina helicinain the arctic, Hudson bay and strait, southward to cape Sable, and in the gulf of St. Lawrence, withL.helicinagenerally more abundant except at the south.L.retroversa, absent in northern collections, was more abundant than the other species from Belle Isle strait to cape Sable, increasing in numbers in the gulf of St. Lawrence in summer.

ISSN:0706-652X    

DOI:10.1139/f40-005

出版商:NRC Research Press    

年代:1940

数据来源: NRC

摘要:

Although as yet the precursor is unknown, the mechanism of dimethylamine production in spoiling cod muscle press juice appears to be similar to that of trimethylamine production.

ISSN:0706-652X    

DOI:10.1139/f40-006

出版商:NRC Research Press    

年代:1940

数据来源: NRC

摘要:

Bacterial spoilage of dressed halibut, pink salmon and black cod is markedly inhibited by icing with crushed ice containing small amounts (0.1 or 0.5 per cent) of sodium nitrite instead of ordinary ice, as demonstrated by bacteriological examination and organoleptic tests, including appearance (halibut excepted), odour and taste. Halibut becomes a marked yellow on the ventral (white) surface. Sodium nitrite ice preserves fish much more efficiently than benzoic acid ice.

ISSN:0706-652X    

DOI:10.1139/f40-007

出版商:NRC Research Press    

年代:1940

数据来源: NRC

摘要:

Two extreme types of fisheries are set up for analysis. In type I natural mortality and recruitment are negligible while fishing is in progress; in type II natural mortality, recruitment and fishing mortality all occur throughout the year at a uniform rate. With either type, the catch per unit effort is proportional to the average population on handwhile fishing is in progress. This statistic is less useful than it may appear, because, in cases of type I, recruitment occurs between the fishing seasons, and in cases of type II, the slow process of removal (or replacement) of accumulated stock following a change in fishing effort makes it difficult to determine the significance of any change in catch per unit effort.A more useful statistic is the rate of exploitation (a fish's annual expectation of death by capture). A theoretical relationship between rate of exploitation and gear in use is here developed for type I fisheries, and is shown to apply fairly well to many cases of type II—so that if rate of exploitation for one year be determined, that for other years can be calculated. For certain special cases of type I fisheries, several methods are proposed by which rate of exploitation might be estimated from ordinary statistics of catch and effort. For other cases of type I, and all cases of type II, an application of Petersen's tagging technique, or data from other outside sources, appear almost essential to determination of the rate of exploitation.

ISSN:0706-652X    

DOI:10.1139/f40-008

出版商:NRC Research Press    

年代:1940

数据来源: NRC

摘要:

The comparative times required for similar lobster eggs already slightly developed, to reach the 16-cell stage, at 18.5, 14.4, 12.3, 10.5, 9.9, and 4.7 °C. are 2, 3, 3.6, 4.8, 5.6 and 25 days respectively.Egg-laying is almost a month later at Grand Manan than in the warmer southern gulf of St. Lawrence areas. Egg-laying in the southern part of the gulf of St. Lawrence takes place in two bursts, the first being egg-laying by old-shelled lobsters usually occurring in the latter half of June and in July, and the second, egg-laying by new-shelled lobsters occurring mainly in August in the warmest areas.Female lobsters rarely lay eggs before becoming hard-shelled. Development of the lobster egg usually requires 11½ to 12 months in Canadian waters.

ISSN:0706-652X    

DOI:10.1139/f40-009

出版商:NRC Research Press    

年代:1940

数据来源: NRC

摘要:

In shallow water of Malpeque bay, P.E.I., the distribution of the starfishAsterias vulgaris, Verrill, is limited by temperatures over 25 °C. in the summer and salinities less than 14 per mille in the winter. Small starfish have a higher temperature tolerance than large starfish. The population on denuded areas is replaced by the immigration of adults and the settlement of larvae. The maximum distance travelled by a marked starfish was 200 metres and the average about 20 metres, in four months. Starfish move directly towards food a distance of 12 metres at 6 metres per day. The maximum population density found was 60,000 per acre (15 per sq. metre) and the greater the population density, the smaller the modal size. Rate of growth varies with the kind and abundance of food and inversely with the size of the starfish. Spawning takes place in late May and early June and the larval life is about three weeks.

ISSN:0706-652X    

DOI:10.1139/f40-010

出版商:NRC Research Press    

年代:1940

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f40-001

出版商:NRC Research Press    

年代:1940

数据来源: NRC