摘要:

Four separate and distinct populations of herring have been identified in Newfoundland waters. They are located during spawning seasons in Bay of Islands, Fortune Bay, Placentia Bay and Notre Dame Bay. They are distinguished by differences in growth, "diameter" of the scales at the end of the first year, and average vertebral counts, also by the length, age, and year-class composition of the spawning aggregations. The herring that are caught off the Labrador coast may be an older and more migratory part of the population that spawns in Notre Dame Bay. The number of vertebrae tends to decrease from south to north in the Newfoundland area, which is the reverse of what is found elsewhere, but temperatureat spawningmay increase from south to north for these populations. The present fishery is chiefly for large (32.4 to 36.4 cm.) and old (7.4 to 11.9 yr.) herring and it is evident that catches could be increased considerably.

ISSN:0706-652X    

DOI:10.1139/f56-028

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Haddock otolith lengths decline from over 5% of the total length of the fish at 14 to 17 cm. to almost 3% at 74 to 77 cm. The otolith lengths of slow-growing haddock decline less rapidly than those of fast-growing haddock. Little difference was found between otolith lengths in male and female haddock of the same length.Slow-growing haddock both from the Grand Bank and from St. Pierre Bank have heavier otoliths than fast-growing haddock at the same fish lengths. This is true not only for fish of different year-classes in the same year but also for fish of the same year-class in different years.The otoliths of male haddock of the Grand Bank exceed progressively in weight the otoliths of females of the same length after the males become sexually mature. The relative increase in otolith weight of the male fish is attributed to a probably slower growth rate after sexual maturity, which occurs earlier than in females. Similarly, the heavier otoliths of mature fish in sizes overlapping with immature fish are due to a greater age of the mature fish at these sizes. Otolith weight relative to fish weight decreased considerably with increase in fish size, and no distinct differences were apparent between otolith weights as a percentage of fish weights in slow-growing and fast-growing fish of the same length.

ISSN:0706-652X    

DOI:10.1139/f56-029

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

FromPhoca vitulina richardithe following parasites are recorded:Corynosoma strumosum(Acanthocephala);Terranova decipiensandContracaecum osculatum(Nematoda);Halarachnesp. (Acarina);Echinophthirius horridus(Anoplura). FromEumetopias jubataare recordedDiphyllobothrium pacificum,Diplogonoporus tetrapterusandAbothrium gadi(Cestoda);T.decipiens,C.osculatumandParafilaroidessp. (Nematoda);Corynosoma villosum(Acanthocephala);Orthohalarachne diminuata(Acarina):Antarctophthirus microchir(Anoplura).E.jubatais probably not a true host ofA.gadi, the parasite apparently being introduced by ingestion of infected fishes of the family Gadidae, the normal definitive hosts. Notes on host and geographical distribution, nomenclature and morphology of the parasites are included.Diphyllobothrium pacificumis a new combination forAdenocephalus pacificus.E.jubatais a new host record forD.pacificum,D.tetrapterusandO.diminuata. Several new geographical records are reported. The occurrence of larval stages ofT.decipiensandC.strumosumin fishes is noted.

ISSN:0706-652X    

DOI:10.1139/f56-030

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f56-031

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

The relation between physical and chemical indices of production and standard crops of plankton, bottom fauna and fish was examined in 100 British Columbia lakes. A significant increase in plankton and fish quantities with increase in total dissolved solid content of lake waters was demonstrated and a similar relationship suggested for bottom fauna. Although the general form of the relationship between mean depth and plankton, and between bottom fauna and fish quantity, suggested a hyperbolic curve with larger quantities in lakes of low mean depth, the only generalization which seemed justified was that quantities of fauna from lakes of great mean depth were never as high as those found insomelakes of low mean depth. No significant relation was found between intensity and length of growing season and quantities of plankton, bottom fauna or fish, although a significant relationship was demonstrated between summer epilimnion temperature and plankton.In a multiple regression analysis using all lakes the predominance of total dissolved solids over mean depth in affecting summed indices of lake fauna was shown. However for lakes in the southern interior plateau, one of the 9 regions distinguished in British Columbia, no significant relation could be demonstrated between mean depth or total dissolved solids and summed indices of fauna or plankton alone. Thus total dissolved solid content of the water appeared to be the most important factor in determining the general level of productivity in lakes studied throughout the province, although within a region neither total dissolved solids nor mean depth could be used either singly or together to predict plankton, bottom fauna or fish quantities.

ISSN:0706-652X    

DOI:10.1139/f56-032

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Records are given of two species and a variety new to western Canada and notes on three other species already known from the region. A new species,Aricidea lopezi, and four species new to western North America, are described from the neighbourhood of Friday Harbour, Washington.

ISSN:0706-652X    

DOI:10.1139/f56-033

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Whitefish fry were planted in the Bay of Quinte and adjacent waters in numbers varying from 208 millions in 1927 to none in 1945. Since 50% of the commercial whitefish catch from these waters consisted of five-year-old fish, whitefish production in each of the years from 1929 to 1951 was compared to the number of fry planted 5 years previously (1924–1946). No correlation could be found between the number of fry planted and the production of whitefish 5 years later. The largest number of fry planted (208 millions in 1927) was followed by the lowest production of the entire period (95 thousand pounds in 1932). On the other hand, following no planting in 1945, production in 1950 was approximately normal (162 thousand pounds).The age composition of the commercial catch in the years 1944–1951 was determined from scale samples. By applying the age composition to the total catches in these years the contributions of the year-classes 1940–1945 have been estimated. The number of fry planted probably did not affect the contribution of these year-classes to the fishery.

ISSN:0706-652X    

DOI:10.1139/f56-034

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Results are reported from preliminary studies using various analytical methods to detect spoilage in nitrite-treated Atlantic cod. In a more intensive study of one method, it was found that fresh fillets could be separated from spoiling fillets by their gains in tyrosine value after 3-hour incubation at room temperature.

ISSN:0706-652X    

DOI:10.1139/f56-035

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Taste panel assessments of taste, texture, and grade of cooked samples, examination prior to cooking, and analyses of soluble actomyosin and of fat spoilage on frozen rosefish (Sebastes marinus) fillets, with and without treatment with ascorbic acid, stored at −10°F. (−23 °C.) and +10°F. (−12 °C.), are reported.Rosefish fillets stored at +10°F. remained in good condition for 17 to 22 weeks, but became unpalatable in 7 months; stored at −10°F. these conditions applied after 30 weeks and 80 weeks.Ascorbic acid prevented fading of the red pigment and delayed discoloration, but had no effect on the taste panel assessment. Almost no loss in actomyosin extractability occurred at −10°F. up to 85 weeks.

ISSN:0706-652X    

DOI:10.1139/f56-036

出版商:NRC Research Press    

年代:1956

数据来源: NRC

摘要:

Measurements of the currents close to the bottom and at the surface have been made at six stations along a section across the Strait of Georgia from Point Roberts to Galiano Island, and at two stations in Trincomali Channel. After adjusting to the maximum tidal range the mean bottom currents were about 0.3 knot with a maximum of 1 knot. At the surface the mean flood current was 0.45 knot and the mean ebb 0.85 knot, with maxima up to 2 knots. The bottom currents were periodic and appeared to be essentially tidal in character, while the surface currents were a combination of tidal and river run-off flows.

ISSN:0706-652X    

DOI:10.1139/f56-037

出版商:NRC Research Press    

年代:1956

数据来源: NRC