摘要:

Observations of temperature, salinity and dissolved oxygen content in all but one of the inlets of ten or more miles in length along the west coast of Vancouver Island were made by the University of British Columbia in 1959 and some additional observations were made in 1960 and 1961. The data are summarized to provide a general picture of the oceanographic characteristics of fifteen inlets. Attention is drawn to various features, and comparisons are made with the previous data which are available for only five of the inlets here described. Comparisons are also made with inlets in the mainland coast of British Columbia previously described by Pickard in 1961 in the Journal of the Fisheries Research Board of Canada.Generally the Vancouver Island inlets are shorter and shallower than those of the mainland coast and have shallower sills. The river runoff into the inlets is considerably less than into the mainland ones and has a winter maximum in contrast to the summer maximum on the mainland.Surface salinities during the summer in 1959, 1960 and 1961 were in most cases between 12 and 28‰ at the inlet head increasing to 27–31‰ at the mouth, while surface temperatures were between 10 and 15 °C. The low-salinity surface layer had a thickness of 2 m or less in all but two cases. Secchi disc depths were usually from 4 to 8 m. The deep water characteristics were from 7.5 to 9.5 °C and 31 to 33.6‰ except in the Clayoquot Sound group where the water was warmer (to 15.4 °C) and less saline (to 24.8‰). Dissolved oxygen values were very variable even along individual inlets. At depths greater than 100 m the content was usually less than 4 ml/l and in many cases less than 1 ml/l. The effect of the shallow sills in limiting deep water circulation appeared to be significant.Even when all the available data are assembled there are no time series of observations sufficient to prepare a description of seasonal variations of water properties, but data for six years from 1939 to 1961 are available for Alberni Inlet and for three years for the Nootka Sound inlets and for Neroutsos Inlet. These data indicate that in the deep water changes of up to 0.4‰ in salinity, 1 °C in temperature and 2.5 ml/l in dissolved oxygen content may occur from year to year.An hypothesis is advanced that, on account of the relatively shallow sills of many of the inlets, the deep water in their basins forms a 'memory' of extreme (high density) conditions of the continental shelf waters outside the inlets, and that the consistency of the basin water characteristics in the inlets suggests that the water properties observed in the shelf waters in 1959–61 by the Pacific Oceanographic Group may be typical of shelf waters in this region over many years.

ISSN:0706-652X    

DOI:10.1139/f63-080

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The lactic acid content and several acid-soluble phosphorus-containing fractions of lingcod muscle have been measured after periods of storage of up to 6 months at storage temperatures between 0 and −30 °C. The fish were killed in an unexercised condition and frozen either in liquid nitrogen or at the temperature of storage. Glycolysis, as indicated by lactic acid accumulation, clearly proceeded at temperatures down to and including −20 °C, and some evidence was obtained to indicate that it may proceed at a very low rate indeed (of the order of 0.5 μmole lactic acid formed/g of muscle/month, or less) at a temperature of −30 °C. Acid-labile and acid-soluble phosphorus decreased during storage at temperatures down to and including −20 °C in muscle frozen by either procedure, but only in the more slowly frozen muscle at −30 °C. Acid-stable and acid-soluble phosphorus decreased at temperatures down to −20 °C, but not at −30 °C.

ISSN:0706-652X    

DOI:10.1139/f63-081

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Frozen porbeagle (Lamna nasus) steaks from samples obtained under conditions typical of good and of poor handling were examined and their chemical composition determined. Lipid content was low, about 1% in the light muscle and 2% in the red. Phospholipase activity was absent, but considerable hydrolysis of triglyceride occurred. There was no ammonia production from the high urea content, 1.4–1.6%. Taste testing of cooked steaks showed only fair acceptability, an objectionable sour-to-bitter flavour being noted. Although its flavour may be relished by some, it is concluded that frozen porbeagle would not be generally acceptable to North Americans as a top-quality fisheries product.

ISSN:0706-652X    

DOI:10.1139/f63-082

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Vertebral numbers of American plaice in the Northwest Atlantic are compared. Counts ranged from 42 to 48 vertebrae excluding the urostylar half-vertebra.No significant difference was found between vertebral averages of males and females.Averages for an area extending from the Northeast Newfoundland Shelf southward over the whole of the Grand Bank and inshore to include St. Mary's Bay are statistically similar. The average for this area is significantly higher than averages for the Gulf of St. Lawrence, the Labrador Shelf, Flemish Cap and Fortune Bay. However, over the whole area differences are not very great, the range of averages being (for a sample of 30 or more) 45.273–45.806 vertebrae.The possible effects of differences in the time of spawning, larval drift and the inclusion of a large number of year-classes in the various samples are discussed as possible explanations for the low degree of variability in the whole area.The vertebral averages of the year-classes 1942–1953 from St. Mary's Bay are not statistically different.

ISSN:0706-652X    

DOI:10.1139/f63-083

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Roccus americanus(Gmelin) has become part of the Lake Ontario–St. Lawrence River fauna, originating from populations in Upper New York State. The time required for the species to spread through the lower Great Lakes is discussed and summarized. A review of the morphological distinctions of related species is included.

ISSN:0706-652X    

DOI:10.1139/f63-084

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

A semi-empirical method for the tidal calibration of oceanographic models with two ocean approaches is developed. The same method may be extended to models with more than two approaches. Tidal functions (amplitude and phase) at reference stations are expressed in terms of the amplitudes and phases of the tide generators. A Taylor expansion is made about an initial set of conditions imposed on the generators. The result is a set of simultaneous equations, whose coefficients can be found experimentally. Then, knowing the response at the reference points to the initial generator conditions, corrections can be made to obtain any desired tide.The method is applied to the particular case of the Hecate Model. Examples of single- and multiple-component tides are given.

ISSN:0706-652X    

DOI:10.1139/f63-085

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

A small population of maskinonge was exploited by a 9-year fishery, using fixed nets under control of the investigator. During the period 1952 to 1960, approximately 4000 maskinonge were handled, 2000 of them being tagged and returned to the population.The rate of loss of the preopercular disc tag increased progressively with time out, so that an estimated 8.5% of the tags had been lost after the end of the first year, 30% after the second and virtually all after the third. The total mortality and tag loss is estimated to range from 25% to 66% during the period from spring to fall for various years. These estimates are used as correcting factors to determine the numbers of tags extant at the start of the fall fishery each year. The rates of recapture of these tags give estimates of exploitation during the fall fisheries, and the average coefficient of catchability, derived from these data, is 0.0026 for fish age IV and older.A method, using simultaneous tag and recapture data, is developed to estimate the coefficient of catchability for each age-group. The estimated coefficients of catchability increase, almost linearly, from 0.0013 for age-group III to 0.0032 for age-group VI+. The average coefficient estimated by this method, 0.0025 for age-group IV and older, agrees well with that estimated independently by the method above.

ISSN:0706-652X    

DOI:10.1139/f63-086

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The effects of ratio of the amount of fish to that of wash water, kinetic energy of impinging water, method of water application and concentration of available chlorine in the wash water on the washing of eviscerated fresh cod of various caught-ages were studied. The studies were designed to provide information of practical value to engineers interested in designing machines to wash slime and bacteria from fish received at filleting plants. A quantitative relation between kinetic energy of impinging wash water and fish to water ratio was established for one practical type of spray washing equipment. Effective spraying was found to be more efficient than fluming or dipping. However, fish dipped several times in water deposited less bacterial load on a clean surface than fish washed effectively on the skin side only by a jet of water. Thus, washing out the body cavity was found to be important. Caught-age was found to influence the resultsonlyfor washing methods of relatively low effectiveness, namely in fluming and in washing inefficiently with a jet or spray of water. Ineffective spray washing was shown to be associated with waste of equipment and high costs while serving no useful production purpose. Highly effective methods of spray washing fish of all caught-ages were shown to be suitable for efficient application in fish filleting and skinning lines. Free chlorine concentrations as high as 100 ppm in the wash water did not increase washing effectiveness as measured by a bacteriological method.

ISSN:0706-652X    

DOI:10.1139/f63-087

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The reactions to light stimuli of juvenile Atlantic salmon exposed to photoperiods (light-exposed fish) and those exposed to control conditions (control fish) were compared. The light-exposed fish showed more activity and reacted more readily to stimuli than the control fish. Both the control and light-exposed fish exhibited a negative phototaxis at all light intensities except the very lowest where a slight positive phototaxis was obvious. The intensity of an intermittent light stimulus had very little effect on the intensity of the reaction in the light-exposed fish, while the control fish showed an increase in the intensity of the reaction with an increase in the intensity of the light stimulus. The control fish showed an increase in the reaction to the intermittent light stimulus the longer the stimulus was applied at the higher levels of stimulation, while the light-exposed fish showed this behavior at the lower levels of stimulation. The reactions to continuous light were similar to the reactions to intermittent light stimuli, but the light-exposed fish reacted more quickly to continuous light than the control fish. These differences in behavior are attributed to the increased activity and sensitivity of the light-exposed fish, resulting from their exposure to photoperiods.

ISSN:0706-652X    

DOI:10.1139/f63-088

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Observations made on the biology of the pollock in the western Atlantic, and primarily in the Bay of Fundy region of the northern Gulf of Maine, are presented. The largest landings of pollock in the western Atlantic are made in this area (ICNAF Division 4X). The best catches of large fish are made at temperatures above 1.1 °C, at depths of 20–100 fathoms (35–185 m) on the edges of shoals and banks where food is abundant. Spawning occurs in the winter and takes place in the southern Gulf of Maine and probably also on the Scotian Shelf, but not in the northern Gulf of Maine. The Bay of Fundy pollock are recruited from spawning in the southern Gulf of Maine and possibly on the Scotian Shelf. The pollock found in the Bay of Fundy appear to remain separate from those of the southern Gulf of Maine and the Scotian Shelf in the summer, but migrate south, spawn and probably mix with those of the southern Gulf of Maine, and possibly also those of the Scotian Shelf in the winter. The offshore pollock have a regular gradient in size across the Bay of Fundy; large fish (65–85 cm) are caught on the New Brunswick side, medium-sized fish (60–75 cm) around Grand Manan and smaller fish (45–60 cm) off western Nova Scotia. Catches with different size compositions are also found in small areas. Segregation by size into schools is therefore an important feature of pollock behaviour. The growth rate of pollock is rapid until the approximate time of sexual maturity, which occurs at ages of 4–7 years (50–65 cm) in the males and 5–7 years (55–70 cm) in the females. The growth rate of the immature and young, mature fish is similar to that recorded for other areas, but the older, mature fish appear to grow more slowly. It is suggested that this discrepancy may be due to biased sampling of the old fish in the Bay of Fundy due to the segregation by size. The 0-class pollock found in the shallow, sublittoral zone feed mainly on algae-inhabiting organisms and to a lesser extent on plankton. The 1-year-olds in the same location have a similar diet but consume a greater proportion of planktonic animals. The larger, offshore pollock in the Bay of Fundy are predominantly plankton eaters, and the euphausiidMeganyctiphanes norvegicais by far the most important organism in the diet. On the Scotian Shelf and in the Laurentian Channel fish is the dominant type of food, except for the smallest sizes of pollock.

ISSN:0706-652X    

DOI:10.1139/f63-089

出版商:NRC Research Press    

年代:1963

数据来源: NRC