摘要:

During the winters of 1959 to 1962, 2459 commercial-sized cod were tagged off the Canadian coast south of the Laurentian Channel. Most returns came from the same general area. Very few cod crossed the Laurentian Channel to Newfoundland or Gulf of St. Lawrence North Shore grounds, or the Scotian Gulf to grounds off western Nova Scotia. Several cod populations were observed, each moving south in autumn and north in spring months. Fish tagged off central Nova Scotia did not migrate as far as the Gulf of St. Lawrence, but those tagged off Cape Breton migrated into the southwestern Gulf for summer months. Fish marked in the middle of the area were intermediate in their migration pattern.Temperature and feeding appear to be the important factors associated with cod migrations. Cod remain in temperatures of 1° to 4 °C during winter months by moving to deeper water. In spring, cod disperse and feed in shoaler water. The cod of the Western-Emerald Banks area move east over the Scotian Shelf. The Gulf cod move up through the cold-water layer and north to inshore feeding near the Magdalen Islands and the Gaspé peninsula.

ISSN:0706-652X    

DOI:10.1139/f64-019

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

One hundred and fifty-eight samples of sea lamprey (Petromyzon marinusL.) blood were analyzed using paper electrophoresis at pH 8.6. The specimens were of two phases in lamprey life history, the parasitic phase and pre-spawning phase. Variations in serum protein concentration, positions and sizes of the fractions were associated with the state of life history, sex and disease. Most of the variation between phases of life history was in the dominant fraction, an albumin. There was a decrease in total stainable protein while specimens were starved in captivity. Disease caused several changes in the pattern, the most striking of which was an increase in the size of fraction 6, probably α-globulin.

ISSN:0706-652X    

DOI:10.1139/f64-020

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Consideration of recent analytical data supports the conclusion that the longer-chain polyunsaturated fatty acids of marine origin are all structurally homogeneous in that the double bonds arecis, the double bonds methylene interrupted, and that, with the exception of the C16chain length, the ultimate double bond will normally be three, six or nine carbon atoms removed from the terminal methyl group.

ISSN:0706-652X    

DOI:10.1139/f64-021

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Certain aspects of the performance and biochemistry of adult migrating salmonid fishes were investigated during ascents of 1:16- and 1:8-slope experimental fishways which employed locking devices permitting the simulation of fishways of any length. Fish tested were chinook salmon (Oncorhynchus tshawytscha), sockeye salmon (O.nerka) and steelhead trout (Salmo gairdneri) diverted from their upstream migration on the Columbia river at the Bonneville dam fishways during the summer of 1959. Blood and muscle lactate, and muscle and liver glycogen levels were determined in control fish, and in fish following three types of activity. Records of individual performance were kept.All species were willing to enter and capable of ascending fishways of either slope up to 1000 ft in height under favourable hydraulic conditions. Blood lactate and muscle glycogen determinations revealed the degree of exercise to be moderate even during prolonged ascents. Moderately high ascents (about 100 ft) in the steeper fishway apparently required the expenditure of some muscle glycogen whereas similar ascents in the 1:16 fishway did not. When muscle glycogen was utilized during prolonged ascents the expenditure appeared to be progressive. All species were apparently able to adapt to prolonged ascents of either fishway. Certain fish of each species tended to stop moving of their own volition in both fishways. After a 60-min volitional stop some evidence of recovery from the effects of exercise was observed. Discussion of the above data is presented.

ISSN:0706-652X    

DOI:10.1139/f64-022

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

A knowledge of the rate of vertical movement of a planktonic population is a prerequisite for the interpretation of the role that various factors play in depth control. A method for estimating this characteristic of a planktonic population ofDaphniais described. Several estimates of the net rate of movement have been determined within each of the four periods that characterize the migratory behavior ofDaphniain Lake Mendota, Wisconsin; a series of rates were calculated for each of 11 cruises of approximately 24-hr duration. In most cases, a linear relationship exists between the rate of vertical movement and the rate of change in the logarithm of the light intensity; a number of such relationships are summarized for three of the four periods of movement. An increase in the slope of this relationship with increasing temperature is evidence that the rate of movement inDaphniais proportional to temperature. The consistent pattern of the rates of movement during the dawn rise and the subsequent regularity in timing of the morning maximum in relation to sunrise together provide the most striking aspect of the diel migration in Mendota. From the onset of the dawn rise, the rate of upward movement increases to a maximum at or slightly preceding sunrise and hence decreases to zero at the time of the morning maximum. Typically, the maximal rates do not exceed 1.5 m/hr. The mean morning maximum at the surface occurs 60.2 min following sunrise, with a standard deviation of 37.2 min; the mean evening maximum at the surface occurs 19.4 min before sunset, with a standard deviation of 61.0 min. Those morning maxima which deviate substantially from the mean were commonly formed under conditions of moderate to heavy cloud-cover. Behavioral evidence suggests a threshold of visual sensitivity of 10−4to 10−5lux forDaphnia. The mean amplitude of vertical movement characteristic ofDaphniain Mendota is 0.87 m, with a range from 0.29 m to 1.52 m. Comparative evidence supports the conclusion that the magnitude of the observed amplitudes of vertical movement are logical for an eutrophic lake such as Mendota. Aggregations ofDaphniaat various levels present a problem in the design of a program to determine the periodicity of diel migration. Various types of aggregations are summarized within a framework of related environmental factors and with a description of the methods employed to meet the problem.

ISSN:0706-652X    

DOI:10.1139/f64-023

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The component fatty acids of cod liver oil from a single fish have been determined by gas–liquid chromatography on several polyester columns with identifications by the linear log plot and separation factor procedures. A number of acids have been detected which are not listed in recent comparable studies.

ISSN:0706-652X    

DOI:10.1139/f64-024

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

An oceanographic section made with the research vesselCrawfordin June 1959 showed that the proportion of Labrador-Coastal Water to Slope Water at the meridian 57°30′W was unusually large. Data from this section combined with bathythermograms taken elsewhere in the Slope Water area and direct deep current measurements suggest that there was an abnormal influx of cold water from the Labrador Basin in 1959. This suggestion is strengthened by the high incidence of coastal fog in the summer of 1959. It is suggested that the cause of this influx was an abnormal North Atlantic weather pattern in January 1959.

ISSN:0706-652X    

DOI:10.1139/f64-025

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The milky condition in some Pacific coast fishes was studied because of its effect on quality and salability of fishery products. Affected milky areas displayed relatively high proteolytic activity, whereas adjacent unlysed areas showed little or no activity. The proximate composition for the whole fish remained within normal limits. The myxosporidian parasites causing the condition were readily identified microscopically by their characteristic spores.

ISSN:0706-652X    

DOI:10.1139/f64-026

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The early stages in the recovery of the dorsal fin of the Atlantic cod (Gadus morhua) to a "clean cut injury" are described. It is concluded that the observed rapid epidermal migration, wound closure and cell mitosis are essentially the same inin-vivoas inin-vitroexperiments. An accumulation of carbohydrate material occurs in the outermost layer of epidermal cells. There is a change in the carbohydrate composition or structure in the dermal layers at the site of injury. The basal epidermal cells rapidly divide in thein-vitroculture whereas only those basal epidermal cells in anin-vivoinjury in close proximity to the injury divide. The surrounding nutrient medium inin-vitrocultures does not appear to be involved in the initial cell migration. However, ascorbic acid does stimulate epidermal migration, mucous secretion, and basal epidermal cell mitosis.

ISSN:0706-652X    

DOI:10.1139/f64-027

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Reference is made to Krøyer's description of the hermit crab,Pagurus pubescens, and to Stimpson's later description ofP.krøyeri. Comparison of specimens ofkrøyeriwith the type specimen ofpubescensshowed them to be identical. The American species thought by Stimpson to bepubescensand, therefore, left without a name, is now given a name,P.arcuatus. Both species are compared withP.trigonocheirus, and a new diagnostic character, the shape of the anterior division of the third sternite, is used.

ISSN:0706-652X    

DOI:10.1139/f64-028

出版商:NRC Research Press    

年代:1964

数据来源: NRC