摘要:

Trout-perch of Heming Lake attain III years of age and 90 mm. in fork length. In May they ascend small tributaries to spawn on silt and boulder bottoms, at a temperature of 40°–50°F. Average egg content was 349, with range 210–728 in 11 fish. Trout-perch taken in the lake were infested with 0 to 6 cysts each (av. 1.4) containing procercoids of the cestodeTriaenophorus stizostedionis. Most cysts were in the liver or gonads, very few in the muscle. Trout-perch were eaten in large numbers by pike,Esox lucius, and much less frequently by walleye,Stizostedion vitreum. Only the latter contained adultTriaenophorous stizostedionis.

ISSN:0706-652X    

DOI:10.1139/f54-001

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Winter catches of lake trout in the sports fishery exceeded those taken at other times of the year in some Algonquin Park lakes. The size of the fish caught was generally smaller because of the different type of gear used in winter. The winter fishing also exploited a high percentage of the immature stock.The winter diet was less varied than at other seasons and there was a high percentage of empty stomachs. Bottom feeding was negligible in most lakes, but, in some, insect larvae were taken more frequently than at any other time of the year. Plankton feeding was at a low level in winter even in those lakes which have predominantly plankton-feeding populations in summer. In these same lakes the absence of thermal barriers permitted trout to feed more frequently on fish in winter and also on a greater variety of fish species. Populations feeding on fish in summer continued to do so in winter. As the winter progressed, there was a decline in the frequency of plankton in the stomachs and an increase in fish and bottom fauna.

ISSN:0706-652X    

DOI:10.1139/f54-002

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

A European ling, 137 cm. long, caught on the Grand Bank, February, 1953, is identified asMolva molva. This is the first substantiated record from North American waters south of Greenland.

ISSN:0706-652X    

DOI:10.1139/f54-003

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Surface-current measurements were made at half-hour intervals throughout thirty-hour periods at three positions in Juan de Fuca Strait. These were repeated during spring and neap ranges of the tide in spring, summer and late autumn during 1952. The currents are linear functions of the difference of sea level between the Pacific Ocean and the Strait of Georgia. A rule is given for predicting the currents from data in the Tide Tables.

ISSN:0706-652X    

DOI:10.1139/f54-004

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f54-005

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Five short series of surface and bottom current measurements were made at one position in Hecate Strait during July 1952. The surface currents were dextro-rotary, while the bottom currents were laevo-rotary and the dominant flows were parallel to the nearby coast-line. At the surface there was evidence of a steady southerly flow of about one-third knot.

ISSN:0706-652X    

DOI:10.1139/f54-006

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Injections of an alkaline extract of the anterior lobe of beef pituitary produced a prolonged acceleration of growth in rats and a temporary increase in weight of goldfish. A comparable extract of salmon pituitaries (Oncorhynchus tshawytscha) had no effect on growth of rats but produced a slight temporary increase in growth of goldfish. Negative effects of salmon extracts on rats are considered significant, but all effects on goldfish are questioned since the extracts were not free of toxicity.

ISSN:0706-652X    

DOI:10.1139/f54-007

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Testes of mature chum salmon (Oncorhynchus ketaWalbaum) were examined histologically for interstitial cells and extracts of testes assayed biologically for the presence of androgens. The histological examination showed numerous interstitial cells similar to those described in some other fish and in mammals. The bioassay established the presence of androgenic substance (probably testosterone). The amount present in salmon testes was calculated to be roughly equivalent to the amount present in mammalian testes.

ISSN:0706-652X    

DOI:10.1139/f54-008

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Behaviour patterns of juvenile sockeye salmon in fresh water are compared with those of chum and coho salmon. Both sockeye and chum fry are schooling fish, responding positively to currents and avoiding shallow waters. Of the two species, chums, however, form more active schools, travel more rapidly, have a less marked cover reaction and prefer stronger light and shallower water. Sockeye smolts, in contrast to coho smolts, are more active, show little thigmotactic and territorial behaviour and a more persistent response to current. The experimental findings are discussed in relation to the migratory behaviour of these fish. It is suggested that sockeye fry, emerging from cover as the light intensity falls are displaced downstream after dark. Moderate activity and a marked preference for deep water are mechanisms postulated for continued residence of sockeye fry in lakes. Further it is suggested that the smolt exodus is due to heightened general activity, both day and night, associated with strong response to current. This brings sockeye smolts into the outflow from the lake where they hold position during the day but are displaced down the river after dark. Coho smolts, responding less vigorously to currents and maintaining a measure of contact with specific objects in their environment, move seaward more slowly than sockeye.

ISSN:0706-652X    

DOI:10.1139/f54-009

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

A list is given of 61 stations where biological or oceanographic observations or collections were made by theCalanusin Ungava Bay, Frobisher Bay, Cumberland Sound and adjacent waters, during the 1951 and 1952 seasons. Five additional stations, occupied independently from theCalanusin Frobisher Bay in 1948, 1950 and 1951, and at Resolution Island in 1950, are included.

ISSN:0706-652X    

DOI:10.1139/f54-010

出版商:NRC Research Press    

年代:1954

数据来源: NRC