摘要:

New and previously published records are given for 19 species of Cetacea stranded naturally, netted, or shot on the coasts of eastern Canada from Cape Chidley, Labrador (60°30′N), to the United States border (45°N), from 1949 to 1968. The most commonly recorded species wereGlobicephala melaena,Phocoena phocoena,Balaenoptera physalus, andDelphinapterus leucas. Occurrence ofStenella coeruleoalbaat Sable Island was confirmed. Four blue whales (Balaenoptera musculus) stranded naturally, three of them in the western Gulf of St. Lawrence. Groups of fin whales (B.physalus) were twice stranded by ice in western Newfoundland. The greatest number of species stranded at Sable Island (44°N, 60°W).

ISSN:0706-652X    

DOI:10.1139/f70-216

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Samples collected during January and October 1968 from 44° to 19°N in the western North Atlantic were analysed for particulate organic carbon, ATP, DNA, chlorophylla, and total particulate volume between 1 and 40 μ diameter. Although the ratio of chlorophyll to ATP decreased from north to south, the ratio of particulate carbon to ATP did not show any systematic trend. A good correlation was found between ATP and DNA even though the DNA concentration was too great to be entirely representative of living material. Growth or production of particulate material as measured by the Coulter Counter method was higher than that measured by C-14 method. A trend was noted towards higher specific growth rate with smaller standing crop in southern waters.

ISSN:0706-652X    

DOI:10.1139/f70-217

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

External receptors located in the snout region of Atlantic salmon parr are innervated by the facial nerve and are differentially sensitive to several chloride salts (NaCl = KCl > MgCl2 > CaCl2). They are also sensitive to mineral and organic acids but insensitive to uncharged molecules such as neutral amino acids and simple sugars.The palatine organ containing taste buds situated on the roof of the mouth is sensitive to strongly ionized as well as uncharged molecules.The two classes of receptors differ in temporal patterns of discharge and in their susceptibility to the blocking agents Hg++and Pb++and the potentiating agent Cu++.Salmon parr can detect Hg++in concentrations lower than other divalent cations as judged electrophysiologically; food pellets treated with dilute solutions of Hg++are rejected by the fish.As chain length increases in the aliphatic acid series the compounds become increasingly stimulatory as measured by nerve discharges in the palatine nerve.Inert carriers treated with aliphatic acids of increasing chain length become increasingly preferred by salmon, and carriers treated with valeric and caproic acid are ingested.Anosmic fish are capable of discriminating chemically treated carriers in a way similar to fish in which the olfactory organ is intact.The cellular nature of external receptors of the snout is uncertain; the possibility that they are neuromasts is discussed.

ISSN:0706-652X    

DOI:10.1139/f70-218

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Sixty-six specimens ofSebastodes alutus, the Pacific ocean perch, collected from the coast of Oregon and British Columbia were examined for parasitic copepods. The six species identified areChondracanthus pinguisWilson, 1912,Chondracanthus triventricosussp.nov.,Clavella parvaWilson, 1912,Brachiella robusta(Wilson 1912) Kabata, 1970,Colobomatus kyphosussp.nov., andSarcotaces arcticusCollett 1874.Colobomatus kyphosusis the second species of the genus to be described from the eastern Pacific andCh.triventricosusis the second chondracanthid to be found in nasal cavities.Sarcotaces arcticusis reported as a parasite ofS.alutusfor the first time. Details of the appendages of each new species are described and illustrated.

ISSN:0706-652X    

DOI:10.1139/f70-219

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The tubificid oligochaetes build up populations in excess of 200,000/m2in Toronto Harbour. Pollution-tolerant species in great abundance are located around the mouth of the Don River, whereas small numbers and some less tolerant species are found near the island shores. There is no evidence of diurnal rhythms in the vertical distribution of the worms in the sediment. Dry weights for tubificids are about 16% of the wet weight for fresh-starved worms. The ash content averaged 34% of the dry weight for worms with a gut full of mud, but 11% for worms clear of gut contents.

ISSN:0706-652X    

DOI:10.1139/f70-220

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The defecation rate of three tubificids is affected by temperature but the effect differs from species to species. Information on defecation rate and weight change at each experimental temperature suggests an optimum temperature range of 14 C forPeloscolex multisetosus, 18 C forTubifex tubifex, and greater than 20 C forLimnodrilus hoffmeisteri. Downward trends of defecation rate with time were recorded forP.multisetosus, but these were probably due to lowered activity prior to the observed mortality. Upward trends in defecation rate with time inL.hoffmeisterimay indicate continuing acclimation to experimental conditions beyond their 10- to 14-day duration, or a need to process increasing amounts of less nutritious mud because of selective feeding on the richer fractions at the beginning of the assay period. Data on the relative abundance and distribution of species in Toronto Harbour is used to estimate defecation rates of the tubificid populations in the field.

ISSN:0706-652X    

DOI:10.1139/f70-221

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Transfer of bacteria from frozen flounder (Hippoglossoides platessoides) to the water in which they are immersion-thawed was evaluated in a laboratory-scale test. After 6 hr of batch thawing, the water quality was still acceptable. Transfer of bacteria from the thawing water to fillets processed from these fish was minimal. No correlation was evident between the time the thawing water was in use and the bacterial count on the fillets. It was also determined that the frozen fish on removal from storage had low bacteria counts. In no instance were faecal coliforms observed.

ISSN:0706-652X    

DOI:10.1139/f70-222

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Rainbow trout (Salmo gairdneri) from above a waterfall on Kokanee Creek had significantly higher average number of parr marks and scale rows but lower number of vertebrae compared with those living below the falls. Three phenotypic forms of liver lactate dehydrogenase (LDH) were recognized in Kokanee Creek rainbow trout (two single-banded homozygous forms CC and C′C′ and a five-banded heterozygous form CC′), apparently under the control of a two allele system. Homozygote CC was predominant in trout from the above falls population and homozygote C′C′ was predominant in those from below the falls. Possible origins of meristic and LDH differences between above- and below-falls populations are discussed and their significance to differences in behaviour, particularly migratory, are considered.

ISSN:0706-652X    

DOI:10.1139/f70-223

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Postmortem biochemical changes in the white muscle of white sucker and of northern pike were, in general, similar to those observed in other species as reported previously by other investigators. However, glycogen content of pike was found to remain relatively high even after 7 days of storage in ice. This is in contrast to the findings with several other species, including white sucker, where the muscle glycogen is practically completely degraded in 3–4 days. Higher glycogen content in the posterior portion of pike muscle as compared with that in the anterior portion may partly explain the apparent high glycogen content in the muscle of this fish after several days of storage.

ISSN:0706-652X    

DOI:10.1139/f70-224

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Fifty percent of the salmon 5′-nucleotidase is in the soluble fraction after high-speed centrifugation. A threefold purification on a Sephadex G-200 column gives a specific activity of 0.5 μmoles UMP hydrolyzed per hour per milligram of protein. ThepH activity curve gives a single peak with an optimum atpH 9.0 MgCl2, CaCl2, and MnSO4increase the activity whereas Zn acetate, Ni acetate, and CoSO4inhibit the enzyme. EDTA, KF 2-mercaptoethanol, and dithiothreitol inhibit the nucleotidase activity. It is stable for up to 1 week at 0 C and up to 2 hr at 35 C, but activity decreases to 50% after 15 min at 50 C and no activity is left after 15 min at 60 C. The nucleotidase shows greatest activity towards 5′-nucleotides; 2′(3′) nucleotides and 5′-deoxynucleotides are hydrolyzed less effectively. Ribose-5-phosphate andp-nitrophenylphosphate are hydrolyzed, but no activity is exhibited against fructose-1-phosphate and α-glycerophosphate.

ISSN:0706-652X    

DOI:10.1139/f70-225

出版商:NRC Research Press    

年代:1970

数据来源: NRC