摘要:

Xenomystax atrariusGilbert has been considered a possible representative of as many as three eel families (Congridae, Muraenesocidae, and Nettastomidae) by recent authors. Although the species is described in detail in this account, it cannot be definitely assigned to a family without major revision of these families. The species is now known from 19 specimens captured mostly near the continental slope of the eastern Pacific Ocean between Valparaiso, Chile, and Vancouver Island, B.C.Xenomystax rictusGarman 1899 should be considered a junior subjective synonym ofX.atrariusGilbert 1891.

ISSN:0706-652X    

DOI:10.1139/f72-001

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Sexual maturation in male pink salmon (Oncorhynchus gorbuscha) from Jones Creek, a tributary of the Fraser River, British Columbia, was accelerated by intraperitoneal injections of partially purified chinook salmon (O.tshawytscha) gonadotropin. The treated pinks produced milt 1 year earlier than normal. Milt from these fish was compared with milt from wild Lower Babine River pinks with respect to its ability to fertilize the ova of Lower Babine River females. There were no marked differences in proportions of ova fertilized, in survival to hatching, or in numbers of deformed larvae. Densities of sperm in the milt from treated males ranged from 0.15 × 109to 7.35 × 109 per ml; sperm densities in the milt from wild males ranged from 19.3 × 109to 38.6 × 109 per ml. Two stages in testicular development were identified among the treated males and found to be directly related to the success of fertilization. The significance of induced early maturation in attempts to establish pink runs in the "off" year rivers is discussed.

ISSN:0706-652X    

DOI:10.1139/f72-002

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

A method is proposed for obtaining frequency-dependent values of wave force coefficients for marine structural forms. If orbital velocity (or acceleration) components and wave force measurements are directly available, the coefficients are obtained without recourse to any particular wave theory. However, linearity of the wave-force process is implicit in the use of the Morison force equation. Modifications of the method are indicated for use when velocities must be inferred from measurements of wave parameters other than velocity, or from their power spectra, by means of a chosen wave theory. The feasibility of the method for obtaining wave force coefficients as a function of frequency is demonstrated using data reported by another worker for force measurements on a sphere.

ISSN:0706-652X    

DOI:10.1139/f72-003

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The experiments were conducted in large outdoor concrete pools in which the salmon had access to a safe haven. After exposure for 24 hr to 1.0 ppm of the organophosphate insecticide, Sumithion, Atlantic salmon (Salmo salar) parr were more vulnerable than unexposed fish to prédation by large brook trout (Salvelinus fontinalis). Sumithion at 0.1 ppm, and DDT at 0.07 ppm, had no noticeable effect. The results, particularly for Sumithion, correlate well with previous laboratory work on the effect of insecticides on the learning ability of salmon.

ISSN:0706-652X    

DOI:10.1139/f72-004

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The attached algal assemblage on navigational buoys and natural rock substrate in Lake Winnipeg in 1969–70 was examined, in the fall after 145 days growth, as part of an overall limnological survey of this important Canadian Great Lake. Only three phyla were represented: Cyanophyta, Chlorophyta, and Chrysophyta (Bacillariophyceae). Green and blue-green algae were more abundant in the south basin, and diatoms were more common in the more oligotrophic north basin.Ulothrix zonataoccurred only on substrates in the north basin, andCladophoracf.callicomawas found only in the south basin. On both natural and artificial substrates a distinct zonation pattern related to water transparency or available light was prevalent. Preliminary results indicated that light was the most important physical factor affecting growth and specific composition of attached algae on substrates in Lake Winnipeg. Biomass values from all stations (dry weight) ranged from 1.7 to 29.1 mg/cm2; with the greatest values consistently occurring between 10 and 25 cm deep on buoys in the south basin. Diatom density and diatom volume were estimated from buoy samples and varied respectively, within the range 2.00 × 105–6.65 × 106diatoms/cm2and 0.32–10.00 mm3/cm2. Though direct evidence is lacking, it appears that nutrients may limit growth of attached algae in the north basin, whereas in the south basin, light is the major limiting factor. The specific composition of the algal assemblages on particular buoys was more related to the physical–chemical features of a major river plume in close proximity to the buoy than to a homogeneous Lake Winnipeg water mass. This factor, together with greater turbidity in the shallower south basin, is largely responsible for the observed heterogeneity among the attached algal assemblages in Lake Winnipeg.

ISSN:0706-652X    

DOI:10.1139/f72-005

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

In slowly flowing water, seven naive goldfish 30-cm long changed their locomotor behavior upon entering a mass of water containing shallow gradients of copper chloride. The concentration was 11–17 μg/liter Cu++in most of this mass, with small isolated pockets containing maximally 50 μg/liter. The amount of time spent by the fish, the average size of turn, and the variance of the size of turn increased in the "polluted" region. The orientation of the fish in this region deviated consistently in the upstream direction resulting in the increase in time spent in the area of highest concentration. Comparison of the locomotor behavior of the fish in sodium chloride of the same concentration and in laboratory water established that the changes mentioned were in response to the copper rather than the chloride ion.

ISSN:0706-652X    

DOI:10.1139/f72-006

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The chemical and spectroscopic characteristics of humic compounds isolated from decomposed thalli ofFucus vesiculosusandLaminaria digitata, seaweed exudate, and dissolved organic matter in river water show that, in spite of several differences, their gross structural features are similar to those of humic compounds isolated from marine sediments or soils. Dominant functional groups are carboxyl and carbonyl but phenolic and alcoholic hydroxyl groups are also present in small proportions. Between 20 and 40% of humic acids are represented by fractions having molecular weight greater than 200,000, whereas the fulvic acids do not exceed 10,000. Carbon and nitrogen contents show a direct relation with molecular weight whereas the oxygen is inversely related.

ISSN:0706-652X    

DOI:10.1139/f72-007

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Wescodyne®and Betadine®, organic iodine complexes, were compared in vitro for virucidal activity against infectious hematopoietic necrosis (IHN), infectious pancreatic necrosis (IPN), and viral hemorrhagic septicemia (VHS) viruses. Both iodophors were about equally effective on all three viruses. Each iodophor completely destroyed IHN virus within 30 sec at 12 ppm iodine, and was not affected by water hardness. Virucidal activity, however, was reduced atpH levels above 8.0 and in the presence of organic matter. Wescodyne was also compared with seven disinfectants commonly used in fish hatcheries, for virucidal properties against IHN virus. Wescodyne and chlorine were the only disinfectants to completely destroy the virus. Either Wescodyne or Betadine would effectively destroy the salmonid viruses at less than 25 ppm iodine within 5 min in solutions near neutrality.

ISSN:0706-652X    

DOI:10.1139/f72-008

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Active and standard metabolism ofKuhlia sandvicensisincrease with fish weight to a power of about 0.8 and active is nine times standard. No significant difference was found between experiments in fresh water and 30‰ sea water at 23 C. At low swimming speeds the fish may be unable to physically take up as much oxygen as at higher speeds. Swimming activity may be essential to circulatory adequacy.Elevated oxygen consumption lasted for 42 hr following a ration of 2.3% of body weight and for 60 hr after one of 4.5%. It amounted to about 76 mg O2/g ration, equivalent to about 16% of the energy of the ration, in both cases. For a nonswimming fish the highest oxygen consumption observed following the maximum daily ration is no more than half of the difference between active and standard rates.

ISSN:0706-652X    

DOI:10.1139/f72-009

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Distribution and abundance of 27 planktonic crustaceans in an inshore area of Georgian Bay characterized by horizontal differences in temperature and electrolyte concentrations are described on the basis of duplicate vertical hauls on eight dates at six stations during ice-free months of 1970 and on one date at four stations through the ice in 1971. Most species were found at all stations on at least some occasions in 1970, although some differences in periods of maximum abundance between stations, probably related to temperature, were noted.Daphnia ambiguaandDiaptomus reighardiwere confined to the inner stations.Limnocalanus macrurusandDiaptomus siciliswere absent during periods of highest water temperatures.Eubosmina coregoni, although found throughout the system in February 1971, was restricted to the outer stations in 1970. A marked late-summer drop in populations of all species exceptBosmina longirostrisandTropocyclops prasinus mexicanusin 1970 might have been due to either normal seasonal fluctuations or heavy predation by planktivorous fish.

ISSN:0706-652X    

DOI:10.1139/f72-010

出版商:NRC Research Press    

年代:1972

数据来源: NRC