摘要:

The temporal variations of water characteristics and currents are reviewed both for the oceanic region of the eastern Subarctic Pacific and for the bordering coastal and fjord regions.In the oceanic region, an estuarine structure prevails, namely, an upper zone, halocline, and lower zone. The horizontal distributions of temperature of the upper zone (seasonal) for the years 1955 to 1966, and lower zone waters for the same years, excepting 1963 and 1964, off the British Columbia coast are presented. The extent of warm upper-zone waters was greatest in 1958 and 1963 and least in 1956 and 1965. Warm lower-zone waters extended furthest in 1958, 1961, and 1962, but did not retreat to the position observed in 1956. The mechanisms relating these waters to the bottom waters of the continental shelf are discussed.In the coastal and the inshore waters there is a pronounced annual cycle in the upper zone, generally with a temperature maximum and a salinity maximum in the summer. The deep water of the fjords opening directly on the Pacific is, in some cases, exchanged annually in the summer, when higher density subsurface water moves onto the continental shelf. In the fjords with indirect connection to the ocean, the deep water is exchanged irregularly at intervals of several years.

ISSN:0706-652X    

DOI:10.1139/f67-182

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The formation of hypoxanthine in ordinary muscle was followed in 36 individual yellow walleye (Stizostedion vitreum) and in 22 individual whitefish (Coregonus clupeaformis) stored in ice. At the time of death, the average hypoxanthine content was approximately the same for the two species (0.25 μmole/g); it increased gradually to 1.52 μmole/g in 22 days and to 2.54 μmole/g in 18 days in yellow walleye and in whitefish respectively. The average rate of formation in yellow walleye (0.06 μmole/g per day) was the same as in ordinary muscle of swordfish; the rate of formation in whitefish (0.13 μmole/g per day) was slightly higher than that of Atlantic salmon, but lower than that of haddock, petrale sole, and several other marine species. Large variation in rate of formation was noticed between individual yellow walleyes. The average hypoxanthine content of both yellow walleyes and whitefish taken as groups was found to be proportional to the number of days in storage. No difference in average rate of formation was noticed between whitefish fillets from opposite sides of the fish, nor between fresh and thawed fish. The hypoxanthine content appears to be suitable as an index of freshness for groups of fish, not of individual fish.

ISSN:0706-652X    

DOI:10.1139/f67-183

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

On the basis of bottom samples and echograms from Kouchibouguac Bay and Northumberland Strait, the bottom topography, bottom lithology, and sediment distribution of the area are described and conclusions drawn regarding the composition of the underlying bedrock and the history of the sediments. A series of maps drawn after hydrographic charts dating back to 1839 show a buildup of the offshore barriers and underwater bars southeastward in the direction of long shore currents. Comparisons between maps illustrating bottom topography and bottom sediments show areas of topographic highs to be composed of bedrock and gravel whereas the topographic depressions consist chiefly of sand. Studies of the petrological composition of bedrock fragments and the gravel fraction reveal that green sandstone is the most common rock type in the samples from the inner part of Kouchibouguac Bay and probably underlies much of the area. On the basis of the abundant reddish-brown rocks in the samples from the outer part of the bay and the central area of Northumberland Strait it is concluded that the Scouduc Formation forms the bedrock in this area, whereas the red sandstone in samples near the coast of Prince Edward Island have been derived from the formations that form this island. Sediment colour and heavy mineral composition of the samples resemble that of the local sedimentary formations and indicate that the sand is derived from these rocks.The gravel in the area consists of glacial material, more or less reworked by wave action. The sand in the bay also appears to be relict material. This is concluded from the occurrence of sand deposits interpreted on the basis of sedimentary parameters, relation to topography, and association with present-day river mouths, as former river deposits. In a 1–2 mile-wide zone along the offshore barrier, wave action controls the deposition and distribution as shown by both normal decrease of mean diameter seaward and negative skewness values in the sediments.

ISSN:0706-652X    

DOI:10.1139/f67-184

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

The blood oxygen capacity of the rainbow trout has been investigated as a function of thermal acclimation in terms of erythrocyte abundance, packed cell volume, hemoglobin concentrations, and mean erythrocytic volume and hemoglobin content. Fish at the lower acclimation temperatures employed (3, 7 C) were characterized by relatively low erythrocyte counts, hematocrits, and hemoglobin levels. Mean erythrocyte volumes tended to be relatively high, whereas mean erythrocytic hemoglobin content was somewhat below that typical of the higher temperature groups. In general, animals held at intermediate temperatures (11, 14, 17 C) showed significant increases in oxygen-carrying capacity by comparison with cold-acclimated fish. Finally trout at 21 C typically had larger numbers of somewhat smaller red cells, more hemoglobin, and higher levels of hemoglobin per erythrocyte than either the low- or intermediate-temperature fish. Significant differences were observed between summer and fall–winter series of trout, particularly with respect to hemoglobin levels. The results are discussed in relation to the general problem of respiratory thermoadaptation.

ISSN:0706-652X    

DOI:10.1139/f67-185

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

As shown by the C14method, the primary productivity of phytoplankton in Marion Lake, a small shallow coastal lake, was very low and was concentrated almost entirely in the 5-month period June to October. Even on the sunniest days, productivity of the surface was not inhibited in contrast to results from most freshwater and marine studies. No explanation could be given. Measurements made simultaneously at 0.5 m at 20 stations covering the lake showed a trend to lower productivity as the water flowed from the inlet to the outlet except when the water passed a large spring. Here productivity increased, suggesting that nutrients were definitely limiting productivity. There was a close relationship between productivity and temperature but not between productivity and light. This suggested that the water temperature prevents full utilization of the available light energy and nutrients during 7 months of the year. The average producivity under a square metre of lake surface was estimated as only 8 g C/m2per year, and efficiency of conversion of available sun's energy to plant material as only 0.0009%. The low efficiency reflected the very low concentrations of nutrients in the lake water, the high flushing rate, and the low water temperature during 7 months of the year.

ISSN:0706-652X    

DOI:10.1139/f67-186

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Auditory thresholds were determined by means of a conditioned response to sound stimuli at frequencies 17.6, 35.3, 70.7, 141, 283, and 400 cycles/sec for 10 cod,Gadus morhua. The conditioned response was a change of cardiac rhythm. It was established through an electric shock as unconditioned stimulus, and could be monitored on an oscilloscope.The thresholds indicated cod to have high sensitivity to sounds up to 283 cycles/sec. At 400 cycles/sec they were relatively deaf. Background noise in the experimental tank was high enough to influence thresholds; an absolute threshold could therefore not be determined.

ISSN:0706-652X    

DOI:10.1139/f67-187

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

During May and June 1966, the migration of pink salmon fry from the Bella Coola River was studied in Burke Channel, British Columbia. The movement of pink fry down Burke Channel was saltatory. Short periods of active migration were interspersed with longer periods when the fry did not migrate and accumulated in bays. Fry were sampled from these accumulations and their ability to orient using celestial cues was examined. During the early morning, fry tended to prefer directions at right angles to their direction of migration, but at other times of the day preferred the direction of migration. The preference for the direction of migration was strongest at midday. Fry were better oriented on clear days than on cloudy days. These data indicate that fry may use celestial cues to find directions during their oceanic migrations.

ISSN:0706-652X    

DOI:10.1139/f67-188

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

Total serum protein values, hemocyte numbers, and muscle weights were determined for 216 intermolt lobsters immediately after their capture, and for 230 others held captive under a variety of dietary and environmental conditions. Average muscle values ranged from approximately 13% to the more normal 20–25% of the live animals' weight, depending upon experimental conditions. The total serum protein up to a level of 55 mg/ml was shown to be a reliable indicator of muscle weights, although the relationship was not identical for all lobster groups. It appeared to be modified chiefly by the areas from which the different groups were taken. Diet was more important than the temperatures (5 to 14 C) in affecting changes in muscle and serum protein values. Starvation caused a greater reduction (50 to 70%) in the size of the hepatopancreas than in the muscle. Histological examination of the hepatopancreatic tissue showed that the lipid content was markedly reduced upon starvation and that a degeneration of this organ was apparent for lobsters fed a beef liver and herring diet. Measurement of serum proteins would appear to be a useful technique in experiments on lobster nutrition and have value, within specified limits, for assessing the physiological condition of wild lobsters.

ISSN:0706-652X    

DOI:10.1139/f67-189

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

A simple metabolic model describing growth as the difference between what enters the body and what leaves it, is elaborated assuming that synthetic processes (the building-up, the anabolism) are consuming energy supplied by processes of decomposition (the break-down, the catabolism). This leads to partitioning total catabolism into two components, one being a function of the rate of synthesis, another keeping the body functioning independently of synthesis. The rate of synthesis is described as a function of food taken, of the efficiencies of digestion and energy conversion, and of the absorbing surface of the intestine. Catabolic processes are supposed to be functions of the oxygen concentration in the water, the absorbing surface of the gills, and the rate of oxygen transport. Both kinds of processes are made functions of temperature in the way enzymatic processes usually are. Assuming that molecular interactions accidentally go wrong makes natural mortality, like growth, a function of the rates of anabolic and catabolic processes and body size.Application of the model to data of length-at-age, food and oxygen consumption, weight loss, gill area, and natural mortality indicates that at least some of the main hypotheses cannot be rejected on available evidence.

ISSN:0706-652X    

DOI:10.1139/f67-190

出版商:NRC Research Press    

年代:1967

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f67-191

出版商:NRC Research Press    

年代:1967

数据来源: NRC