摘要:

Based largely on collections from theCalanus–Salvelinusexpeditions, 54 species of thecate hydroids were identified from the shelf waters of northern Canada between northeastern Newfoundland and the Alaska–Yukon border. Common species includedHalecium muricatum,Calycella syringa,Campanularia integra,C.speciosa,C.volubilis,Gonothyraea loveni,Filellum serpens,Lafoea gracillima,Sertularella polyzonias,S.tricuspidata,Sertularia schmidti, andS.similis.Halecium groenlandicum,H.scutum,Cuspidella procumbens,Calycella gracilis, andSertularia schmidtiare new records for North America;Ptychogena lacteais previously known from this continent only as the medusa. Twenty-two species are reported in northern Canada for the first time, bringing to 71 the number of thecate species recorded from the region. Nearly half of the 71 species recorded are circumpolar in distribution, and over two-thirds transgress both arctic and subarctic zones.Most samples had a paucity of hydroids, particularly those from the high arctic. Collection records indicate that the most favourable regions for hydroids in northern Canada are the Strait of Belle Isle, eastern Ungava Bay, eastern Hudson Strait, northern and southeastern Hudson Bay, Foxe Channel, and northern Foxe Basin.

ISSN:0706-652X    

DOI:10.1139/f70-175

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Vertebral averages were not useful in separating Greenland halibut stocks of the northwest Atlantic, apart from the possible separation of the Gulf of St. Lawrence population.Mean numbers of vertebrae did not differ significantly at the 5% level within the main areas in samples collected between 1950 and 1968 from Baffin Bay to the southern Grand Bank. Mean numbers of vertebrae for each of these main areas also were, with one exception, not significantly different. Mean vertebral numbers of Greenland halibut from the northern Gulf of St. Lawrence (61.850 ± 0.057 SE) differed (P < 0.001) from the overall mean for the remainder of the northwest Atlantic (61.575 ± 0.014).The similar means were associated with similar temperatures at depths of 800 m and over, where eggs and early larvae are presumed to develop. Means of vertebral numbers of males and females were not significantly different.Precaudal and caudal vertebral numbers were negatively correlated. Fused vertebrae were not numerous and did not show much localization except toward the posterior end of the vertebral column, especially in the two most posterior whole vertebrae. The numerical value of each fused partial vertebra was very close to one.Anal and dorsal fin-ray numbers were highly correlated but were not correlated significantly with vertebral numbers. The means of dorsal and anal fin-ray numbers in a few samples from west Greenland to the southern Grand Bank were not significantly different.

ISSN:0706-652X    

DOI:10.1139/f70-176

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Three lactate dehydrogenase phenotypes, CC, CC′, and C′C′, were encountered in the livers of rainbow trout (Salmo gairdneri) resident in Kokanee Creek, which flows into the west arm of Kootenay Lake, B.C. The rare subunit C occurred in high frequency in specimens from this area. Two additional lactate dehydrogenase subunits, designated E1and E2in this study, and not reported previously, were found in the gill tissues of common stocks of rainbow trout homozygous for the C′C′ phenotype, raising the total number of molecular species, based on 10 electrophoretically distinct subunits, to at least 23 for this species.

ISSN:0706-652X    

DOI:10.1139/f70-177

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

A study was conducted to determine the influence of various environmental parameters on the ability of the northern quahaug,Mercenaria mercenaria, to cleanse itself of artificially accumulatedEscherichia coli. The elimination ofE.colito low residual levels in the quahaugs placed in sea water free ofE.colifor 48-72 hr was dependent on their initialE.colicontent and, hence, the level of the organism in the contaminating water. Extending the contamination interval from 6 hr to 14 days did not adversely affect the ability of the animals to cleanse themselves of the organisms they accumulated. Optimal elimination was obtained within the following environmental limits: temperature, 10–20 C; salinity, 22–3‰; flow rate, > 13 ml/min per animal; turbidity, trace to 25 Jackson Turbidity Units. When the ambient temperature of the water from which the animals were collected was less than 10 C, the elimination ofE.coliwas decreased. Preliminary data were presented to demonstrate the importance of examining the variability in the response of individual animals.

ISSN:0706-652X    

DOI:10.1139/f70-178

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Factors significant to the uptake and elimination of coliform bacteria by the soft shell clam,Mya arenaria, were investigated. Uptake kinetics resembling those in the northern quahaug suggest that a steady state exists in functioning animals wherein the number of organisms taken in and eliminated are in balance. In contrast to the quahaug, most of the animals accumulate the organisms very shortly after being placed in the environmental water. The lower limits on the temperature, salinity, and flow rate of the environmental water for acceptable elimination (depuration) were about 10 C, 20‰, and 7 ml/rain per animal respectively. In the feasibility study for a flow-through depuration system using naturally polluted animals, consistently good elimination to very low elevated temperature (ET) coliform levels was observed if the initial level of contamination did not exceed about 2000 ET coliforms per 100 g. Results comparable with those in the flow-through system were obtained in a recirculating depuration system, thereby indicating the feasibility of the recirculating depuration system for the elimination of coliforms in marginally polluted animals.

ISSN:0706-652X    

DOI:10.1139/f70-179

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The effect of various periods of prefreezing storage for iced, whole redfish (Sebastes marinus mentella) on the frozen-storage keeping times (at −23 C) of the fillets and the effect of various periods of fillet storage at temperatures equal to and higher than −23 C are reported. The fish were caught on the Grand Bank and on Banquereau in May and June. Assessment was by taste panel with chemical tests for protein solubility, rancidity, andpH made for purposes of comparison.Fish iced 2 days, then processed and frozen, were of acceptable quality for 83–94 weeks; those iced for 12 days, then filleted and frozen, had a storage life to unacceptability of 51 weeks. Samples processed and frozen after 4 days in ice and subjected to variation in temperature (−23 C; −12 C) during initial frozen storage, then stored at a final temperature of −18 C, as in transportation aboard a refrigerated vessel and in cold storages used in the marketing chain, had initial quality characteristics similar to fish iced for 12 days (then processed and frozen) but had a shorter storage life to unacceptability, 44 weeks. Fish iced 15 days were unacceptable for freezing.

ISSN:0706-652X    

DOI:10.1139/f70-180

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Morphometric measurements and gonad examination of the spider crab,Chionoecetes opilio, showed that 50% maturity occurred at about 57 and 50 mm carapace width for males and females, with minimum sizes at maturity of 51 (males) and 47 mm (females). Both sexes were mature at sizes considerably below the commercially acceptable size of 4 inches (102 mm) carapace width. After maturity, positive allometric growth was demonstrated for males. Females do not moult after reaching maturity. The small vasa deferentia found in soft-shelled mature males suggested that only hard-shelled males were capable of mating. A hard-shelled male successfully mated with a soft-shelled mature female. Field and laboratory observations suggest that more than one brood is commonly produced from one mating.The minimum size limit for commercial landings allows some mature males capable of mating to be left on the fishing grounds. Retention of this limit seems unlikely to affect the breeding potential of the population.

ISSN:0706-652X    

DOI:10.1139/f70-181

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Three main patterns of transferrins, made up of two molecular types, were found by starch–agar electrophoresis in plasma of hatchery and wild Atlantic salmon (Salmo salar).Distributions of the observed patterns from progenies of three hatchery matings agreed with expected Mendelian distributions in offspring of known parentage, implying that the bands have their origin in two codominant alleles. In nearly all samples of the wild salmon the genetic basis of transferrin variation was demonstrated by nonsignificant differences between observed and expected distributions when the Hardy–Weinberg formula was applied.Frequencies of the TfAallele differed in samples from different rivers and within the same river; the Atlantic salmon forms genetically different populations. Interchange of stocks probably influenced the values of the different gene frequencies found.

ISSN:0706-652X    

DOI:10.1139/f70-182

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Experiments were carried out on rainbow trout to see if cannulae implanted at different positions on the operculum yield accurate estimates of mean expired oxygen tension. This value is frequently used to calculate utilization or ventilation volume in fish and should therefore be accurately determined.Opercular oxygen tensionrecorded from seven quiescent fish (383–426 g, 10–12 C) in aquaria was highly variable with respect to time and cannula placement. Expiredrecorded from cannulae placed in the middle, upper, or lower part of the posterior margin of the operculum ranged from 54 to 157 mm Hg and was sometimes identical with inspired. When the fish were chased, expired oxygen tension usually rose but the magnitude of the rise and its duration were not uniform from cannula placement to placement. Other studies, on 21 trout (217–388 g, 10–12.5 C) whose gills were perfused with water at different flow rates with a mouth tube, indicated that thevariability existed over a wide range of perfusion rates. In addition,levels from all three placements at perfusion rates approximating those of normal ventilation were frequently below the mean expired oxygen tension calculated from oxygen uptake and gill water-flow rate data.It is concluded that opercular cannulae provide poor estimates of mean expired oxygen tension in trout. The use of this technique to determine meancould lead to serious errors. It appears that large changes in oxygen utilization can be detected with opercular cannulae but any utilization values determined in this way would likely be erroneous.

ISSN:0706-652X    

DOI:10.1139/f70-183

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Some species of fish use "ram ventilation" to pass water over the gills while swimming. Hydrodynamic analysis provides estimates of the pressure losses as the water passes through the gill spaces, and of the resistance force that must be overcome by the swimming muscles. For a 44-cm skipjack tuna (Katsuwonus pelamis), swimming at its basal speed of 66 cm/sec, the gill resistance is estimated to be 1090 dynes or 7% of the total swimming resistance. If oxygen consumption doubles, gill resistance increases to 27% of the total. The energetic cost of respiration lies between 1 and 3% of the total metabolism at basal swimming speed.

ISSN:0706-652X    

DOI:10.1139/f70-184

出版商:NRC Research Press    

年代:1970

数据来源: NRC