摘要:

Water samples were collected biweekly from five locations on the Grand River, Ont., from August 16, 1967, to September 1, 1968. Headwater nutrient levels and associated water chemistry were radically altered by the influence of a small city. Processes of recovery occurred downriver in a primarily agricultural watershed. Levels of dissolved oxygen, carbon dioxide,pH, alkalinity, hardness, ammonia, nitrate, and silica followed similar seasonal patterns at all locations. High and widely fluctuating levels of chloride, ammonia, nitrate-N, nitrite, and orthophosphate were evidence of gross enrichment. Nitrate-N, orthophosphate, iron, and sulfate levels varied irregularly during the 13-month period.

ISSN:0706-652X    

DOI:10.1139/f70-091

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

In the meromictic Sunfish Lake the large populations of phytoplankton that are observed periodically were associated with circulation of the mixolimnion. Perhaps some organic dissimilation took place in the lower mixolimnion, recycling nutrients during spring and fall circulation. Phytoplankton was practically absent from the epilimnion during the summer but a population ofOscillatoria agardhiiremained in the metalimnion, where it was responsible for a pronounced and persistent metalimnetic oxygen maximum. The monimolimnion contained about 5100 mg/liter of dissolved solids and the upper mixolimnion about 2200 mg/liter. Ventilation of the monimolimnion did not always coincide with circulation and subsurface springs may have been responsible. Circulation to the lake bottom was observed only once in 18 months.

ISSN:0706-652X    

DOI:10.1139/f70-092

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The effects of coenzyme A (CoA) and carnitine on the oxidation of 0.1 mMK-palmitate-1-14C and K-oleate-1-14C by mitochondrial fractions from lateral line muscle, white muscle, heart, liver, and kidney was studied in rainbow trout (Salmo gairdneri). CoA (0.01–0.10 mM) stimulated the oxidation of fatty acids by mitochondria from lateral line muscle and heart. With all the preparations of mitochondria, fatty acid oxidation was increased by addition of carnitine (1.0 mM) and in the presence of carnitine (1.0 mM), CoA (0.1–1.0 mM) gave a further increase in oxidative activity. Mitochondria from lateral line muscle and heart showed the same range of maximal activity (oxidized substrate at 15 C = 180–200 nmoles/mg N per hr), which was considerably above that found with mitochondria from other tissues. The results suggest similarities in the energy-supplying metabolism in lateral line muscle and heart of trout with respect to the utilization of fatty acids.

ISSN:0706-652X    

DOI:10.1139/f70-093

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Nine species of copepods in the family Lernaeopodidae were collected as parasites of teleost or elasmobranch fishes common to coastal waters of British Columbia. One species (Schistobrachia tertia) has not been previously described. Two species (Dendrapta cameroni longiclavataandLernaeopodina pacifica) are new records for the Canadian fauna. The remaining six includePseudocharopinus dentatus,Clavella adunca, and detailed descriptions ofClavella parva,Clavella perfida,Nectobranchia indivisa, andBrachiella robusta, the last-named displaying a range of morphological variability hitherto unknown in Lernaeopodidae.

ISSN:0706-652X    

DOI:10.1139/f70-094

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

A comprehensive series of observations made throughout a natural phytoplankton bloom suggested that culture experiments are satisfactory analogues of natural plankton systems, at least under bloom conditions. Calorific values suggested that there was no tendency for the phytoplankton to store fat in the senescent phase of the bloom. No single quantity was found to be a suitable indicator of the physiological vigour of the population.

ISSN:0706-652X    

DOI:10.1139/f70-095

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Fifteen genera of helminths (19 species) and two genera of parasitic copepods (2 species) were recovered from 375 threespine sticklebacks (Gasterosteus aculeatusLinnaeus, 1758) taken in 10 sampling areas in Newfoundland and Labrador during 1968 and 1969. Two new host records and two new records for North America are included.

ISSN:0706-652X    

DOI:10.1139/f70-096

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Rainbow trout (Salmo gairdneri) anesthetized with M.S. 222 for periods up to 12 min experience interrenal ascorbate depletion, uremia, and moderate hypercholesterolemia. Anesthesia with neutralized M.S. 222 (pH 7) or benzocaine prevented these changes and significantly reduced the variability in plasma glucose, cholesterol, and cortisol, indicating that the stress of anesthesia with M.S. 222 is due to the lowpK of the sulfonic acid moiety.

ISSN:0706-652X    

DOI:10.1139/f70-097

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Criteria for distinguishing annuli on the scales of Pacific cod,Gadus macrocephalus, are described. Evidence is presented that the criteria enable the ages of most Hecate Strait cod to be correctly determined. The method used to validate the scale-reading technique appears to be a new one; it may be applicable to other species.

ISSN:0706-652X    

DOI:10.1139/f70-098

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

In a survey of walleye (Stizostedion vitreum vitreum) from several lakes in central Canada, starch-gel electrophoresis of muscle myogens showed only the three phenotypes previously reported from Lake St. Clair. Measurements of body ratios and counts of interneural and interhaemal spines and of vertebrae gave no morphological basis for distinguishing between the three protein phenotypes. Although phenotype frequencies varied from lake to lake, within lakes the observed frequencies appeared to agree well with those calculated according to the Hardy–Weinberg rule assuming control by two nondominant alleles. The geographical variation was also consistent with the idea of reinvasion of the sample area from two separate refugia.

ISSN:0706-652X    

DOI:10.1139/f70-099

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The body composition of young sockeye (Oncorhynchus nerka) in the weight range of 0.5–300 g was investigated to further document changes in body composition with growth, and to develop equations that would allow the estimation of total body composition in this species, either in vitro or in vivo, based on easily measured parameters such as fork length, live weight, and total body water. The major components of the fat-free mass (protein, water, and ash) in nonstarving fish were closely related to each other and to fork length. Body fat tended to increase with size, but was not closely related to the other components of body composition. The following equations were derived, allowing the accurate estimation of total water (W), protein (P), and fat-free dry material (FFDM, consisting of protein and ash) in grams, based on the measurement of either water or fork length (L) in centimeters: W = 0.00571 L3.118, P = 0.204 W1.038, and FFDM = 1.113 P. Body fat (F) may be estimated as the difference between wet body weight (M) and the lean mass: F = M − (W + FFDM).These equations are similar to, but not identical to, the relations derived for other species of salmon, based on other published data, and to the respective relations reported in the literature for mammals. The applications of these equations to the nutritional evaluation of wild populations and to quantitative nutritional studies on young sockeye are discussed and illustrated.

ISSN:0706-652X    

DOI:10.1139/f70-100

出版商:NRC Research Press    

年代:1970

数据来源: NRC