摘要:

Yellowtail flounders,Limanda ferruginea, from two Nova Scotian fishing areas, Middle Ground and Western Bank, and a southern region near Cape Cod were compared in 1946 with reference to rate of growth, sexual maturity, age and size composition, otolith growth, relative growth of three body parts, and meristic characters. The oldest and slowest-growing fish occurred on Middle Ground, the youngest and fastest-growing fish in the Cape Cod area. Cape Cod yellowtails matured sexually at a much younger age and smaller size than yellowtails from the other regions. Old large fish predominated in commercial catches from Middle Ground and Western Bank; commercial catches from the Cape Cod area were largely composed of young small fish. The 1943 year-class was dominant among the young age-groups on Western Bank; this year-class was scarce in the Cape Cod sample. The yellowtails of each area showed distinctive patterns of otolith growth. Otoliths of Cape Cod yellowtails differed from those of Middle Ground and Western Bank in the relative amount of growth in different years. Cape Cod fish had smaller heads and pectoral fins and larger otoliths than specimens from the other areas. Mean values of dorsal and anal fin-ray numbers were highest in Middle Ground and lowest in Cape Cod fish. Significant differences existed between the numbers of dorsal and anal fin-rays in Cape Cod yellowtails and each of the other samples; Middle Ground and Western Bank samples were not significantly different. Cape Cod yellowtails differed in all respects from either Middle Ground or Western Bank fish and it was concluded that in 1946 the Cape Cod yellowtails formed a distinct population.Western Bank fish, although closely resembling those of Middle Ground, differed from them in some characteristics. It was suggested that the yellowtails of the two regions formed a large population possessing clines of characters.Water temperatures appeared to be important in contributing to the differences between the populations.

ISSN:0706-652X    

DOI:10.1139/f54-014

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Hydrographic data for late August, 1923, show for the Strait (a) progressive inward movement on the north side of Arctic or sub-Arctic water, (b) progressive outward movement on the south side of Gulf water and (c) a dominant outward flow with evidence of a previous dominant inward flow. Time differences suggest tidal causes for the marked temperature and salinity changes. Current measurements for a double tidal period indicate residual trends of nine and eight miles per day in opposite directions on the north and south sides of the Strait. Inside, the Esquiman Channel shows two contra-clockwise eddies north and south of the Mekattina Bank. In addition, hydrographic data show a strong northeasterly movement along the Newfoundland shore and a weaker southwesterly one along the opposite Quebec shore.Planktonic animals indicate the water movements,Mertensia,Acartia spiniremis,Themisto,PseudalibrotusandOikopleura vanhöffenisurviving to various degrees in the water from the Labrador Current that reaches the centre of the Gulf along the north shore of the Strait and Channel. Other forms characterize the warm shallow water along the Newfoundland shore inside the Strait and show its movement outward to the east coast of Newfoundland. The Greenland seal fishery of winter reflects the inward movement from the Labrador Current. Cod and herring fisheries invade this cool water of the north shore only locally in summer with access of warmer water from the south shore. Lobsters and cunners are very abundant in, but particularly confined to, the warm shallow water mentioned above.

ISSN:0706-652X    

DOI:10.1139/f54-015

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

The quantitative determination of total numbers of red halophilic bacteria in contaminated solar salts and discoloured salt fish has been made possible through the successful adaptation of the "drop plate" method. The maximum number of colonies is reached after eight days for pure strains ofPs.salinaria, and after 14 days for the red halophiles present in contaminated solar salts. A brief statistical study has shown that a fair degree of reliability can be obtained with the method. From series of counts, the total error expressed as coefficient of variation is shown to vary from 3.34 to 8.72 per cent. Good reproducibility is also obtained when random samples are taken from stocks of contaminated salt.

ISSN:0706-652X    

DOI:10.1139/f54-016

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

A parasite-host list and host-parasite list, with complete references, of the ecto- and endo-parasites recorded from marine mammals of the North American west coast are presented. One trematode, 7 nematodes, 1 acanthocephalid, 1 copepod, 6 cirripedes, 5 amphipods and a lamprey are reported from 12 species of Cetacea. From 8 species of Pinnipedia, 5 trematodes, 4 cestodes, 12 nematodes, 7 acanthocephalids, 5 Acarina and 4 Anoplura are listed. A single species of Fissipedia has yielded 4 trematodes, 1 cestode, 1 nematode and 2 acanthocephalids, almost all of which have been found in Pinnipedia.

ISSN:0706-652X    

DOI:10.1139/f54-017

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

On the basis of 2,003 lake whitefish,Coregonus clupeaformis, tagged in 1938, of which 126 were recovered during the next five years, there is evidence that fish released together tend to stay together for years, and that the proportion of a population captured during a certain time by a unit amount of fishing effort can fluctuate greatly (a plausible explanation is the effect of variations in weather conditions). On the basis of age determinations of 12,975 whitefish in samples taken annually from 1937 to 1951, growth rate was determined, the total annual mortality rate among fully exploited fish was calculated to be 64 per cent over several years, and it appeared that all year-classes had been of about equal strength in recent years. The generally accepted idea that fluctations in fishing success correspond to fluctuations in abundance of whitefish is probably erroneous. Possibly the Lake Winnipeg whitefish are underfished.

ISSN:0706-652X    

DOI:10.1139/f54-018

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

A series of tests were conducted to investigate the sense of smell in migrating coho (Oncorhynchus kisutch) and spring salmon (O.tshawytscha). By pouring dilute solutions of each of 54 substances into the path of the salmon moving up a fish ladder at Stamp Falls, B.C., positive responses were noted by recording changes in the rate of migration. Representative samples of alcohols, aldehydes, ketones, esters, organic acids and oils, as well as shark repellent and a pulp-mill effluent caused no significant change in the migration. However, dilute water rinses of mammalian skins had distinct repellent action. An acute olfactory sense enabling adult Pacific salmon to detect predators from a downstream position was considered to have survival value. The use of mammalian predator skins to repel salmon from destructive river locations is suggested.

ISSN:0706-652X    

DOI:10.1139/f54-019

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Three species of "whale-lice" (Cyamidae: Amphipoda) are recorded from whales caught in Canadian Pacific seas:Cyamus scammoniDall, 1872, fromRhachianectes glaucus;Cyamus catodontisn. sp., fromPhyseter catodon; andParacyamus boopis(Lütken, 1870), fromMegaptera nodosa.Cyamus catodontisis described and illustrated.

ISSN:0706-652X    

DOI:10.1139/f54-020

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Dodecaceria fewkesi(Fewkes) is a new name for the cirratulid polychaete formerly known asD.pacifica. It builds colonies of calcareous tubes on rock faces in suitable localities on the east and west coasts of Vancouver Island between tide-marks. A sexual reproduction by autotomy followed by regeneration is common and colonies seem to result from a single individual by a repeated operation of this process. Individuals in a given colony are invariably of one sex. Fertile eggs could not be obtained either by mixing ripe oocytes and sperms or by adding sperms to water containing female colonies. They did result from keeping male and female colonies together, provided the colonies had been recently removed from their natural habitat. The early stages of development are described and figured.

ISSN:0706-652X    

DOI:10.1139/f54-021

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

The "Spanish flag" or "flag snapper" (Sebastodes rubrivinctus) is of common occurrence in the long-line catches from deep water adjacent to the British Columbia coast, but has not previously received formal recognition. It is recognizable by the four wide, bright red vertical bands on the sides of the body, the background being white or pale pink. About 100,000 pounds were landed by Canadian fishermen in 1952.

ISSN:0706-652X    

DOI:10.1139/f54-022

出版商:NRC Research Press    

年代:1954

数据来源: NRC