摘要:

Seasonal relationships between size, bottom temperature, and distribution of cod are described for the western Gulf of St. Lawrence and Nova Scotia Banks.In summer, in the western Gulf of St. Lawrence, cod are distributed from 35 to 145 m at bottom temperatures from −0° to 6 °C. They are most abundant at about 100 m where the temperature is around 1 °C. In winter they are concentrated in 130–180 m along the western slope of the Laurentian Channel at bottom temperatures from 1° to 3 °C.On the Nova Scotia Banks cod are less abundant than in the Gulf of St. Lawrence. They are found mainly around Banquereau, Middle Ground, and the northern edges of Sable Island Bank. Further to the west cod are replaced by haddock as the dominant species. Nova Scotia Banks cod are found in shallower and warmer waters than Gulf cod, both in summer and winter. In summer they are present from 65 to 110 m at bottom temperatures varying from about 1° to 8 °C. In winter they are taken primarily at 90–135 m at bottom temperatures from 2° to 4 °C.Area and depth distributions of commercial catches reflect the seasonal pattern of cod migrations and distributions demonstrated in surveys and tagging studies.

ISSN:0706-652X    

DOI:10.1139/f64-038

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The type specimens ofArgis larwere collected in the north Pacific. They are no longer in existence. Specimens identified asA.larby Rathbun, from the type locality and resembling the original specimens of Owen, are used to set up a neotype. This is done because some authors have assumed that specimens ofArgiscollected in the north Atlantic wereA.larand notA.dentatawhich they believed was not a valid species. Also the distribution of both species in northern Canadian waters is not yet clearly understood. Outstanding differences between the two species are discussed.

ISSN:0706-652X    

DOI:10.1139/f64-039

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The component fatty acids of cod roe resemble the flesh lipid fatty acids to a considerable degree. Comparison with the liver lipids of male and female fish suggests that less essential longer-chain monounsaturated fatty acids from the liver depot fat are metabolized by the female for the synthesis of particular fatty acids required by the developing eggs.

ISSN:0706-652X    

DOI:10.1139/f64-040

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Various types of reproduction curves have found extensive use in management and analysis of fish populations. To these may be added curves based on depensatory processes of mortality. Life-history stages may be considered as successive "stock and recruitment" relationships, the output from one process comprising the input of the next. A variety of reproduction curves can thus be generated by considering differing sequences of compensatory and/or depensatory processes.

ISSN:0706-652X    

DOI:10.1139/f64-041

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The degree of preference of sockeye salmon (Oncorhynchus nerka) for spawning in specific tributaries to Brooks and Karluk Lakes, Alaska, was studied in 1960 and 1961. Adult sockeye salmon begin to congregate around stream mouths soon after entering these lakes. At Brooks Lake, groups of fish were seined from various stream mouths and marked with distinctive tag color combinations. One group of tagged fish from each seine haul was released back into the original donor congregation as a control, and one or more groups were transported and released into congregations around other tributary mouths. Strength of tributary preference was determined by comparing the number of fish from each group distributed on the various spawning grounds. Eighty-three per cent of the 958 fish tagged were recovered at weirs and on stream and lake surveys. Distribution to spawning areas of sockeye salmon in control and transported groups was virtually identical. The study at Brooks Lake was followed by a study at Karluk Lake to explore further the strength of tributary preference. Very few sockeye salmon experimentally prevented from entering their preferred tributary chose an alternative spawning area. Most continued to attempt to enter their blocked tributary until death. A final study at Karluk Lake confirmed the fact that sockeye salmon entering the lake were predisposed to spawn in a particular tributary and could not be conditioned to enter an alternative tributary. We conclude that sockeye salmon are indeed homing to particular tributaries in these small lakes. The biological and management implications of these findings are discussed.

ISSN:0706-652X    

DOI:10.1139/f64-042

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

An annual cycle of primary production was established for a British Columbia fjord. Detailed oceanographic analyses of the total oxygen budget of the fjord provided a biological oxygen budget that was further apportioned into estimations of the gross primary production (24), net primary production (24), and subeuphotic utilization of organic material. The values for 1958–59 were 671, 381, and 290 g C/m2/yr, respectively. Using C14data, corrected for observed respiration and variations in insolation, 24-hr gross and net primary production estimations of 609 and 455 g C/m2/yr were derived. Over 90% of the year's primary production was attributed to the nannoplankton. The relation between the physical environmental factors of the fjord and primary production is discussed.

ISSN:0706-652X    

DOI:10.1139/f64-043

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Thaw-drip from once-frozen fall-caught Newfoundland cod (Gadus morhuaL.), thawed after storage at −23 °C for up toweeks, was equal to total drip from twice-frozen fish treated with sodium tripolyphosphate between freezings. Treatment of twice-frozen cod before the first freezing only had no effect on reducing total thaw-drip below that from twice-frozen untreated samples and the yield, although higher in the former than in the latter, was no better than that from once-frozen untreated fillets. Yields from twice-frozen fish were improved greatly by dipping prior to the second freezing and by dipping before each freezing. Treatment between freezings gave yields close to 100% of initial fillet weight whereas losses with the untreated once- and twice-frozen product appear close to 7 and 15%, respectively.With summer-caught trap fish, characterized by higher thaw-drip values which were not affected by treatment, yields of twice-frozen cod were improved; however, losses were still about 12% in fish treated between freezings.Treatment of twice-frozen cod from the two sources did not appreciably affect lipid hydrolysis or protein denaturation. However, lipid content and free fatty acid production were significantly higher in the trap fish samples as compared to the fall-caught cod.

ISSN:0706-652X    

DOI:10.1139/f64-044

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Ligula intestinalisis found in a few species of Heming Lake fish, but occurs principally in the spottail shiner,Notropis hudsonius. A list of possible adult hosts is given. The largestLigula, 91.4 cm long, was found in a sucker 29.5 cm long. Annual and regional differences in the incidence ofLigulain spottail shiners are noted. It is apparent that at Heming Lake, as in other regions, a large population of aquatic birds is not required to produce a high incidence ofLigulain fish.

ISSN:0706-652X    

DOI:10.1139/f64-045

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Four species of ostracods from Indian Arm, British Columbia, are characterized.Paradoxostoma striungulumSmith andConchoecia elegansSars, have variations not previously described.Philomedessp., closely related toP.carcharodontaSmith, was represented by only one specimen. The fourth ostracod is one-third smaller than specimens of similar description which were obtained from the Pacific Ocean Weather Station "P" and which resemble most closelyC.alata majorRudjakov. This smaller ostracod is proposed as a new subspecies,C.alata minor.

ISSN:0706-652X    

DOI:10.1139/f64-046

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Cooking method modified the taste and texture scores of frozen cod fillets of various qualities. All methods gave high scores with good quality fish, but on samples with frozen storage deterioration, much better discrimination between quality levels was shown by baking and steaming than by frying; texture showed greater differences than taste. Initial quality levels of the fillets prior to freezing had little effect on scores or on the subsequent deterioration of the stored frozen product. Thus baking or possibly steaming is the best cooking method for detection and comparison of quality changes on storage. Frying is the method of choice for the consumer if product quality is in doubt, but any method may be used for a top-quality product.

ISSN:0706-652X    

DOI:10.1139/f64-047

出版商:NRC Research Press    

年代:1964

数据来源: NRC