bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Aspects of Growth and Reproduction of the Bearded Seal, Erignathus barbatus (Erxleben)
Authors: McLaren I. A.
Published: April 2011

This preliminary study is based on material from 113 specimens from the eastern Canadian Arctic. Animals may be aged from the claws up to 9 to 16 years. The male matures at 7 and the female at 6 years. The pup is produced around May 1 and the males are probably in full rut in mid-May. Females which have produced a pup forego ovulation until after the male rut, thus establishing a two-year cycle of pup production. The embryo implants during a 11/2-month period around early August, after 21/2 months of delay in development. The animal grows from 120 cm. in nose–tail length at birth to about 235 cm. The female increases her length by about 33% in the first year and reaches about 91% of her final length at puberty, at 6 years; these figures are somewhat larger than expected from the growth patterns of other Pinnipedia.
Some Effects of Temporary Exposure to Low Dissolved Oxygen Levels on Pacific Salmon Eggs
Authors: Alderdice D. F. , Wickett W. P. , Brett J. R.
Published: April 2011

Eggs of the chum salmon (Oncorhynchus keta) were exposed to various constant levels of dissolved oxygen for a period of seven days. The procedure was repeated with fresh egg samples at various developmental stages. Temperatures were constant at 10 °C. from fertilization to hatching. Estimates of oxygen consumption uninhibited by low dissolved oxygen levels were obtained at various stages of egg development for whole eggs and also on the basis of the weight of larvae, excluding the yolk. Eggs were most sensitive to hypoxia between 100–200 Centigrade degree-days and compensated for reduced oxygen availability by reducing the oxygen demand and rate of development. Very low oxygen levels at early incubation stages resulted in the production of monstrosities. At about the time the circulatory system becomes functional the compensatory reduction in rate of growth under hypoxial conditions is reduced, but eggs no longer survive extreme hypoxial conditions. Eggs subjected to low dissolved oxygen levels just prior to hatching hatch prematurely at a rate dependent on the degree of hypoxia. The maximum premature hatching rate corresponded approximately with the median lethal oxygen level. Estimated median lethal levels rose slowly from fertilization to hatching. Oxygen consumption per egg rose from fertilization to hatching while the consumption per gram of larval tissue declined from a high to a low level at about the time of blastopore closure. Subsequently, a slight rise in the rate occurred up to a level which was more or less constant to hatching. "Critical" dissolved oxygen levels were calculated and they appear to define the oxygen level above which respiratory rate is unmodified by oxygen availability. Critical levels ranged from about 1 p.p.m. in early stages to over 7 p.p.m. shortly before hatching.
A Comparison of Sockeye Salmon Catches at Rivers Inlet and Skeena River, B.C., with Particular Reference to Age at Maturity
Authors: Godfrey Harold
Published: April 2011

Age composition, size and sex data for sockeye salmon catches (1912–1954) at Rivers Inlet and Skeena River, B.C. were compared. For both river systems there were indications of 4- and 5-year cycles of abundance among the 4- and 5-year-old fish, respectively; but the two populations were not necessarily in phase. Tests for correlation between the numbers of parental and offspring fish strongly suggested the dominance of hereditary over environmental influence in determining age at maturity. The two stocks showed much similarity in annual size variation, among each sex and age-class.
Variation with Fish Length, Sex, Stage of Sexual Maturity, and Season in the Appearance and Volume of the Drumming Muscles of the Swim-Bladder in the Haddock, Melanogrammus aeglefinus (L.)
Authors: Templeman Wilfred , Hodder V. M.
Published: April 2011

Observations made as early as 1947 and data collected in 1953 to 1954 and 1956 to 1957 indicate that there is considerable variation in the size and appearance of the drumming muscles of the swim-bladder of haddock with fish length, sex, sexual maturity, and season on the Grand Bank and St. Pierre Bank. For haddock of the same length the data indicate that the drumming muscles of mature male haddock are larger than those of immature males and also of immature and mature females of the same length. In addition the data indicate that a periodicity is exhibited in the size of the muscles of the mature male, the muscles being nearly twice as large during the pre-spawning and spawning period in May and June as they are in October and November. This phenomenon does not occur in female haddock, the drumming muscles of which are considerably smaller than those of male fish of the same size and show no variation in size with the season.It is suggested that the difference in size of the drumming muscles of male and female haddock can serve as a means of determining the sex of haddock landed in the gutted condition by commercial trawlers, at least for the mature fish which make up the bulk of the commercial trawlers' catches. There is some difference between male and female haddock in the colour of drumming muscles, but this seems to be of secondary importance for distinguishing between the sexes.Male haddock probably use the drumming muscles chiefly to produce low-frequency swim-bladder sounds which serve as rallying calls for female and other male haddock to join in spawning activities.
Hyperactivity as a Lethal Factor in Fish
Authors: Black Edgar C.
Published: April 2011

Death occurs in fishes under certain circumstances following severe muscular activity. The precise cause of death is not yet known. However, it is possible that the severe disturbance to acid-base relationships following the large increase of lactic acid liberated from muscle glycogen may be the principal cause of death. Hyperactivity as a lethal factor in fishes is important in the study of biology of fishes and fisheries management.
Climatic Temperature Changes and Commercial Yields of Some Marine Fisheries
Authors: Bell F. Heward , Pruter Alonzo T.
Published: April 2011

A review of the literature suggests need for re-examination of the bases for some reported climatic temperature–fish productivity relationships. In some instances adequate provision does not appear to have been made for changes in the amount of fishing, in economic conditions or in the efficiency of the fishing fleets. Possible fortuitous relationships should be avoided by exhaustive tests of the representativeness of both the temperature and fishery data. They can arise from many sources such as the use of air temperatures to represent subsurface conditions, particularly for short-term periods. Due to the considerable variation in temperatures between stations and between seasonal temperatures at any given station there is a high chance of attaining significant but invalid correlations. Also, the methodology of relating temperature with fishery data, such as time-lagging and correlation analyses, should conform with the life history of the species investigated.Consideration of the above leads to the belief that any possible effects of climatic-temperature changes upon the Pacific and Atlantic halibut stocks appear to have been over-whelmed by fishing.
Some Observations on the Structure and Photomechanical Responses of the Pacific Salmon Retina
Authors: Brett J. R. , Ali M. A.
Published: April 2011

The general structure of the Pacific salmon retina is described. Rods, single cones and twin cones constitute the visual cell layer which, together with the dense pigment layer, undergoes photomechanical changes common to most teleosts. Stages in the contraction and expansion of rods and cones, and the migration of pigments are depicted.In the laboratory, cultured sockeye salmon became well light-adapted in 20–25 minutes, whereas the time for dark-adaptation was of the order of 55–60 minutes.In the Lakelse River, a sample of natural-run sockeye and coho smolts was found to be fully dark-adapted by about 10:00 P.M. when the light intensity at the water surface was 0.03 foot-candle. Pink and chum fry from Hooknose Creek were similarly dark-adapted by about 9:45 P.M. on an evening when the intensity had fallen below 0.002 ft.-c. At the start of evening migration retinal dark-adaptation in sockeye smolts had just started, whereas in pink and chum fry the retina was approximately half dark-adapted when migration commenced.
Population Studies on Juvenile Herring in Barkley Sound, British Columbia
Authors: Hourston Alan S.
Published: April 2011

Population studies were carried out on herring in the juvenile (first year, post-metamorphosis) stage in Barkley Sound in the summers of 1951 to 1954. Their chief objective was to detect and estimate yearly changes in relative abundance. The juveniles were found mostly in shallow, sheltered bays, inlets and channels, mainly on the southeast side of the sound. The stocks apparently arose from different mixtures of the progeny of a series of spawnings extending over two months and located mainly on the northwest side of the sound. Mixing between localities averaged less than one-third. The 1953 and 1954 juvenile populations were above average (both about 640 million fish), while the 1952 population was below average. Upon recruitment to the fishery, the relative strength of these three year-classes was comparable to that observed in the juvenile stage. Thus, surveys of herring abundance at the juvenile stage provide an index of year-class strength at recruitment.
The Mark VI Groundwater Standpipe for Measuring Seepage through Salmon Spawning Gravel
Authors: Terhune L. D. B.
Published: April 2011

The groundwater standpipe is a length of pipe, pointed at one end, and has a number of perforations near the point. This is driven into the gravel, where the groundwater flows through it. The permeability of the gravel is measured by lowering the level of water inside the standpipe, one inch below the level outside, and measuring the rate of inflow. The apparent velocity through the gravel is measured in terms of the rate of dilution of a colour solution in the standpipe. A colour is introduced, and its rate of dilution determined from successive small samples taken at suitable intervals of time.Velocity data from the earlier models were erratic and the permeability calibration did not include the range encountered in nature. In the Mark VI model, the standpipe is open during measurements of permeability. During measurement of groundwater velocity, the colour dilution chamber is completely sealed, colour is introduced and withdrawn through a sphincter valve with a hypodermic syringe. The solution is stirred during the period of dilution.The criteria of the measurements have been reconsidered. The standpipe, auxiliary equipment, and procedure have been redesigned, and the new model recalibrated. All this resulted in some loss of simplicity, but the data are consistent and accurate within 5%. The equipment is still simple and rugged enough for field examination of salmon spawning redds.Complete details of design, construction, and procedure, for use in salmon spawning gravels are given in Appendices.
The Deep Waters in the Laurentian Channel
Authors: Lauzier L. M. , Trites R. W.
Published: April 2011

Data pertinent to the deep warm waters of a three-layer system in the Cabot Strait area of the Laurentian Channel have been collected since 1915. Typical temperature–depth curves indicate that the temperature of the deep layer reaches a maximum at about 250 m. which shows little or no seasonal variations. Observations show warming of the deep layer from the 1920's to the 1950's. This upward trend of temperatures is accompanied by an increase in volume of the deep layer. The deep layer consists of a mixture of "Labrador" and "Slope" waters in which the mixing ratio of the components remains fairly constant from year to year. Fluctuations in temperature of "Labrador" water are reflected by a corresponding change in temperature of the deep layer in the Laurentian Channel. The vertical structure of the waters in the lower Laurentian Channel and the transport of the waters in Cabot Strait suggest that in the deep layers, there is a continuing supply of oceanic waters to the Gulf of St. Lawrence.
Determination of Natural and Fishing Mortalities of Cod and Haddock from Analysis of Tag Records off Western Nova Scotia
Authors: Paloheimo J. E.
Published: April 2011

With marine species the population of tagged fish is unlikely to be a closed one, and previously described methods of determining natural and fishing mortalities are then hardly applicable. It is shown that when no data on effort or catch, related to tag returns, are available, a relationship between fishing and natural mortalities can be calculated, subject to some restrictive assumptions. An independent estimate of total mortality is then necessary to arrive at values of natural and fishing mortality.The method is applied to taggings of cod and haddock off Nova Scotia (McCracken, 1956). For cod the calculations show wide variations in effort. We obtain a rather low value of the natural mortality in the first year of recoveries. In subsequent years the numbers of returns are so low that heavy losses of tags are suspected. For haddock the calculations show that the effort may be constant and that already developed methods (Leslie and Davies, Ketchen, DeLury, Beverton and Holt) may be applied. Results leave several alternative explanations possible, giving a range from 0 to.36 for the instantaneous natural mortality rate, depending on the unknown initial loss of tags.
Proteins in Fish Muscle. 14. God Tropomyosin
Authors: Dingle J. R. , Odense P. H.
Published: April 2011

Tropomyosin has been prepared from Atlantic cod muscle dehydrated with ethanol and ether according to Bailey's procedure. Properties measured included electrophoretic mobility, sedimentation constant, solubility as a function of pH, and viscosity. The preparations contained a small amount of nucleic acid not associated with the protein.
Errors in Estimates of Mortality Obtained from Virtual Populations
Authors: Bishop Yvonne M. M.
Published: April 2011

The bias in individual estimates of the natural mortality coefficient derived from the ratio of successive virtual populations is defined algebraically and is shown to be unchanged whether one or more year-classes is considered, if the mortality coefficients are assumed to be constant for all exploitable fish. Limiting and probable values of this bias are shown graphically for a coefficient of fishing mortality ranging from 0 to −2.0 in the year for which the estimate is obtained. These values are drawn for a true natural mortality of −0.2 and −0.4 and for both an increasing and a decreasing fishing effort. Bias in individual estimates of natural mortality is greatest when there are large fluctuations in fishing effort, particularly when fishing mortality is low relative to natural mortality, and it increases with increased natural mortality.A linear regression of a series of virtual population ratios would in general give an intercept value which underestimated the coefficient of natural mortality, and a slope which overestimated the coefficient of fishing mortality, in situations where F has tended to increase and also where it has had no trend (the "steady state" of Table I). Both these errors would be in the opposite direction during a period when there was a decline in fishing effort.
Diet, Glycogen Reserves and Resistance to Fatigue in Hatchery Rainbow Trout
Authors: Miller R. B. , Sinclair A. C. , Hochachka P. W.
Published: April 2011

In a stream occupied by a resident wild trout population, mortality of introduced hatchery trout is greater than when similar trout are released in a barren stream. From this it has been inferred that in the occupied stream the new-comers cannot find niches and succumb to exhaustion in the open current. A conspicuous rise in blood lactic acid in planted hatchery trout supports this inference.In the present experiment rainbow trout of identical brood stock were raised on two diets; one group received a complete dry pelleted ration, the other, ground liver. After 35 weeks the trout were subjected to varying degrees of exercise, following which blood lactate and liver and muscle glycogen were assayed. It was found that the pellet-fed trout had more glycogen stores before exercise; that during exercise this group maintained its liver glycogen but lost about half the muscle glycogen after 15 minutes of exercise. After 12 hours' rest muscle glycogen had risen to the normal level. In the liver-fed trout liver glycogen was depleted to one-half after 15 minutes' exercise and muscle glycogen fell to one-fifth or lower. Twelve hours rest failed to restore either liver or muscle glycogen. Prolonged exercise in a current of one mile per hour reduced glycogen to about 1/4 in the liver-fed fish; some died during the test, and none returned to normal metabolic states after 24 hours. It is concluded that exhaustion of metabolites such as glycogen plays some part in deaths of planted trout, and that the hatchery diet can materially affect the ability of the fish to survive.
Variation in the Annual Average Weight of Chum Salmon Caught in British Columbia Waters, 1946 to 1958
Authors: Godfrey H.
Published: April 2011

not available
A Concept of Growth in Fishes
Authors: Parker Robert R. , Larkin Peter A.
Published: April 2011

The use of size as a basic determinant of growth rate is discussed and compared to analogous situations described in literature on other physiological rates. Ecological opportunity and physiological opportunity are visualized as the two interacting components that determine growth, both of which are entered at "threshold" sizes. The parabolic function,[Formula: see text]is developed into a growth equation for linear dimensions and its application explored and discussed using steelhead trout and chinook salmon as an example. Significant differences in growth rate are found between life history types and sexes. The chinook data are then treated on a lt+1, lt plot and it is shown how an apparent fit of the von Bertalanffy type growth equation can result from selectivity of fishing for the larger fish of any brood year. Two lines of research are indicated. (1) The independent measurement of the exponent x through study of size-specific metabolic rates, and (2) the relationship between total mortality rate and growth rate. Without this knowledge a satisfactory synthesis of growth rate into a yield equation cannot be achieved.
Additional Observations Concerning Residual Sockeye and Kokanee (Oncorhynchus nerka)
Authors: Ricker W. E.
Published: April 2011

1. During the 1920's, plantings of anadromous sockeye fry in small barren lakes tributary to Stuart Lake produced (in addition to smolts) lake-maturing "residual" sockeye dull in colour at maturity. The samples taken contained a large excess of females. 2. The kokanee of Cultus Lake, caught in 1934–36, were all of one year-class and are now believed to have been progeny of Kootenay Lake (West End) kokanee eggs hatched and reared at Cultus Lake, though not intentionally planted there. These kokanee were of a bright colour at maturity, like their parent stock, and matured mostly at age 2+.
The Growth, Length–Weight Relationship, and Maturity of Haddock (Melanogrammus aeglefinus L.) from the Region of Lockeport, N.S.
Authors: Kohler A. C.
Published: April 2011

Data from samples of commercial landings of inshore Lockeport haddock are used to form a curve of growth in length. Maturity and spawning data for these fish are then related to changes in their length–weight relationship. By combining length–weight and growth-in-length data, a curve of growth in weight is derived for use in yield calculations. Apparent changes in growth of inshore Lockeport haddock between 1926 and 1946–54 are discussed.
Effect of the Ingestion of Triaenophorus Plerocercoids on the Nutritional Characteristics of Whitefish Fillets in the Rations of Puppies
Authors: Crampton E. W.
Published: April 2011

To learn whether or not the ingestion of the cysts would affect the growth, the feed consumption, or the efficiency of feed utilization, 118 newly weaned puppies have been fed in 3- and 4-week trials on diets composed of meat or fish, with and without supplements of a meal mixture, to which in different tests Triaenophorus crassus plerocercoids were added in amounts up to 80 cysts per pound of fish. The levels of plerocercoids ranged from 0.39 to 66.0 per pup per day, equivalent to 1.56 to 264.0 cysts per day for an average man consuming 3000 dietary Calories in 24 hours. Although some tendency toward reduced feed efficiency for growth was observed at the maximum level of ingestion, due probably to a low energy value of the diet (which in this case consisted almost entirely of the cystic material), no statistically significant effect of the T. crassus additions to the basal diets could be detected in these studies. It is concluded that fish fillets contaminated with T. crassus have no detrimental effect on the growth of puppies and presumably the accidental ingestion of such fillets by man would be of no consequence nutritionally.
Salinity Preference, Thyroid Activity and the Seaward Migration of Four Species of Pacific Salmon (Oncorhynchus)
Authors: Baggerman Bertha
Published: April 2011

In juvenile Pacific salmon the changes in salinity preference associated with seaward migration and thyroid activity were studied and used as criteria for the induction of the physiological condition required for migration (migration-disposition).Four species of Oncorhynchus (chum, pink, coho and sockeye) changed preference from fresh to salt water at the onset of seaward migration and maintained this preference throughout the migration season. At the end of this migration period coho and sockeye salmon changed preference from salt to fresh water if retained in fresh water, indicating a re-adaptation to this medium in which they may survive for several years. Chum and pink fry did not show this change in preference and usually died when retained in fresh water. They were apparently unable to re-adapt to this environment.The increasing day length in spring controls the time at which the change in preference from fresh to salt water takes place, and is thus involved in timing the induction of migration-disposition.The photoperiod seems to affect particularly the pituitary-thyroid system. Thyroid activity increases shortly before the onset of migration, remains high during the migration season, and decreases towards its end. The level of thyroid hormone in the blood influences salinity tolerance and preference and, thus, the induction of migration-disposition. Metamorphosis, osmotic "stress" and iodine content of the water may have some additional effect on thyroid activity, but are not the only factors responsible for thyroid hyperactivity during migration.Animals in which migration-disposition has been induced are thought to have become susceptible to appropriate external stimuli "releasing" migration.
The Phosphorus-containing Fractions of Sterile Lingcod Muscle During Storage at 0 °C
Authors: Tomlinson Neil , Creelman Vera M. , Reid K. G.
Published: April 2011

During refrigerator storage of sterile lingcod muscle for up to 3 weeks at 0 °C no significant changes occurred in the P content of the phospholipid, ribonucleic acid, or deoxyribonucleic acid fractions, but in the acid-soluble fraction the portion of total P accounted for by inorganic P increased to 96% from 75%. The P-containing fractions from the fish held in ice for the same period did not differ appreciably from those of the sterile muscle. An aqueous extract of lingcod muscle was shown to be able to form orthophosphate from a variety of phosphorylated compounds.
A Qualitative and Quantitative Study of the Plankton of the Quoddy Region in 1957 and 1958 with Special Reference to the Food of the Herring
Authors: Legaré J. E. Henri , Maclellan Delphine C.
Published: April 2011

Investigations of the composition, abundance, and distribution of plankton communities within the Passamaquoddy region of New Brunswick and Maine were carried out in 1957 and 1958. Studies of the food of herring and possible relationships between zooplankton abundance, feeding activity, fat content, and catches of herring were included in the program. Similar quantities of zooplankton were found outside Passamaquoddy Bay and in Cobscook Bay. Slightly smaller volumes were taken in the passages into the Bay, but only one-fifth as much was taken in samples inside Passamaquoddy Bay. Differences in zooplankton abundance suggest incomplete mixing of outside waters with those of Passamaquoddy Bay. The smallest volumes of zooplankton were taken in the spring and the largest in the summer months. Overall zooplankton volumes were much higher in 1958 than in 1957.There was evidence that herring were feeding in the upper water layers. A period of low feeding activity from March to August was followed by a period of active feeding from September to November. There was a positive correlation between feeding activity and fat content of herring but no relationship between quantities of zooplankton and feeding activity could be established. Nor. was it possible to demonstrate any relationship between zooplankton volumes and catches of herring over a period of 10 years.Higher zooplankton volumes are foreseen for Passamaquoddy Bay after the dams are built. Volumes in Cobscook Bay are expected to reach values similar to those of Passamaquoddy Bay while those outside should remain unchanged.
Observations on the Life History of the Hybrid between Eastern Brook Trout and Lake Trout in Algonquin Park, Ontario
Authors: Martin N. V. , Baldwin N. S.
Published: April 2011

Studies of brook trout × lake trout hybrids planted in Algonquin Park, Ontario lakes since 1954 indicate they are readily available to angling and an excellent game fish. Hybrid trout depth distribution during stratification is between the 8° and 20 °C isotherms. Mayfly nymphs, crayfish, leeches and fish are important in the diet. Hybrids average 12 inches at age II, 16 inches at age III, and 18 inches at age IV. Their length–weight relationship is similar to the lake trout. Most hybrids are mature by age III. Egg production is similar to the brook trout. Hybrids were observed spawning on rocky shoals in early November and had spawning characteristics of each parent. Hybrid trout eggs hatched by the end of April.
Biochemical Studies on Sockeye Salmon During Spawning Migration.: XIII. The Distribution of Phosphorus Compounds, Creatine and Inositol in the Major Tissues
Authors: Chang V. M. , Tsuyuki H. , Idler D. R.
Published: April 2011

The acid-soluble and fat-soluble phosphorus components, acid-soluble, lipid and total inositol and creatine content of the major tissues of sockeye salmon were determined at three locations during its river migration. With the exception of the gonads, these components were found in approximately the same concentration in the corresponding tissues of both sexes at the start of migration. The changes in total phosphate per unit weight during migration were most significant in the alimentary tract and liver of both sexes, and in the gonads of the female. Except for the gonads, the changes in inositol components were similar in both sexes. The same was true of the creatine content. In general, the tissues of the female were somewhat higher than those of the male in creatine, except in the gonads where milt contained 6 to 7 times the amount found in roe.The absolute amounts of the various components were calculated on the basis of the standard fish. A tissue component was sometimes markedly increased or decreased in absolute quantity in the standard fish, due not to a change in the concentration of the constituents but rather to an appreciable change in the weight of the tissue. This was especially true for the alimentary tract and roe.
Inhibition of Bacterially Produced Trimethylamine
Authors: Stewart James E. , Castell C. H.
Published: April 2011

not available
The Macroscopic Bottom Fauna of Lac la Ronge, Saskatchewan
Authors: Oliver D. R.
Published: April 2011

In the summers 1948 to 1953 (except 1951) 796 quantitative dredge samples were taken in the main lake and 172 in Hunter Bay. The 1948 and 1949 populations of the main lake were significantly higher than the 1952 and 1953 populations. No significant yearly difference occurred in Hunter Bay. The amphipods (mainly Pontoporeia affinis) predominated in the oligotrophic Hunter Bay which had 2192 organisms per square metre and dry weight of 6.4 lb per acre. The chironomid larvae (mainly Chironomus anthracinus) predominated in the mesotrophic main lake which had 742 organisms per square metre (7.9 lb/acre, 8.8 kg/ha). The depth distribution of the main groups are given. Correlation of depth with numbers was shown. Numbers in the main lake showed spring and fall maxima, with a summer minimum. The yearly variation was greatest in the chironomid larvae. The ooze type in the upper littoral had the greatest number of organisms. An annotated species list of some groups is given.
An Attempt to Improve Trout Fishing in a New Brunswick Lake by Deferment of Opening of Angling Season
Authors: Smith M. W.
Published: April 2011

Deferment of opening of angling season for brook trout at Crecy Lake, New Brunswick, from April to June 1, resulted in much improved angling in early summer. The improvement was relatively minor in July and August. Earlier removal of stock and adverse effects of high water temperature on feeding of trout conditioned the poorer midsummer angling. There was a lower survival of planted trout to anglers' catches with the late opening.
An Aquarium for Maintaining Constant Prey Population Densities in Studies of Predator–Prey Interactions
Authors: Nicholls C. F. , Doxtator E. A.
Published: April 2011

An adjustable aquarium is described and illustrated. The apparatus provides a means of regulating the effective volume of a tank in relation to variations in prey population.
Seasonal and Diurnal Vertical Distribution of Herring (Clupea harengus L.) in Passamaquoddy, Bay, N.B.
Authors: Brawn Vivien M.
Published: April 2011

The depth of schools of immature herring in Passamaquoddy Bay was determined from echo-sounder records taken from 1947 to 1958. The records gave no information on the presence of herring between the surface and 14 ft, and any herring in this zone have been omitted from the calculations. The herring schools showed diurnal vertical movements, being closer to the surface by night than by day in every month of the year. From May until December the median depth varied from 30 to 44 ft by day and from 21 to 26 ft by night. From January to April the schools were deeper in the water by day with a median depth of 83 to 126 ft, though still rising towards the surface at night, to a median depth of 36 ft in February. No correlation was found between the mean solar radiation for the daylight hours and the median depth of herring by day in each month. Between 2° and 4–7 °C there was a significant inverse correlation between water temperature and the depth of the herring by day, but as temperature increased above 7 °C, up to 12°, there was no further decrease in median depth.
Current Measurements in Passamaquoddy Bay and the Bay of Fundy 1957 and 1958
Authors: Forrester W. D.
Published: April 2011

not available
A Population of Dwarf Coastrange Sculpins (Cottus aleuticus)
Authors: Ricker W. E.
Published: April 2011

Cottus aleuticus in Cultus Lake, British Columbia, inhabits deep water, grows slowly to a maximum length of about 50 mm in 3 or 4 years, and spawns in the lake throughout the summer. It was taken abundantly from the stomachs of Dolly Varden char; other fish eat it only rarely. Its summer food is plankton and microbenthos.
Zooplankton Studies at Ocean Weather Station "P" in the Northeast Pacific Ocean
Authors: McAllister C. D.
Published: April 2011

Concentrations of zooplankton observed at Station "P" (50°N.L., 145°W.L.,) are less than those in the Northwest Pacific, the Bering Sea, British Columbia coastal waters and the Labrador Sea; about equal to those at Station "M" in the Norwegian Sea; and greater than those in the central Equatorial Pacific and the Sargasso Sea. Zooplankton abundance at Station "P" appears representative of that in a wide area of the central Gulf of Alaska. A vertical distribution of zooplankton characterized by maxima of concentration from 0–100 metres and from 200–500 m was observed both day and night and in all seasons. Daily means of concentration of surface zooplankton ranged from about 20 g per 1000 m3 in winter to about 150 in summer. A small autumn maximum was observed. A similar seasonal cycle of abundance occurred down to depths of about 200 m. Below 200 m the amplitude of the seasonal cycle tended to decrease with depth. Vertical hauls captured mainly copepods all year round. Horizontal surface tows revealed a marked seasonal cycle in taxonomic composition. A pronounced diurnal variation in the concentration of surface zooplankton was observed and showed the major features of typical diurnal vertical migration. Night catches of vertical hauls exceeded day catches.
Northward Range Extension of the Flathead Chub and Trout-perch to Aklavik, N.W.T.
Authors: McAllister D. E.
Published: April 2011

not available
A New Record of the Long-finned Cod, Antimora rostrata Gunther, from British Columbia Waters
Authors: Ketchen K. S. , Wilson R. M.
Published: April 2011

not available
A Comparison of Three Methods of Inactivating Lobster Claws
Authors: Wilder D. G. , McLeese D. W.
Published: April 2011

Mortalities during [Formula: see text] months among 4 lots of 50 lobsters, 3 with claws inactivated, were: plugged 54%, banded 56%, cut tendons 78%, untreated 98%. No appreciable loss of claws, bands or plugs occurred. Plugged lobsters are more susceptible than banded to infection with with Gaffkya homari, the agent causing lobster blood disease. The advantages of banding outweight the disadvantages.
Dietary Marine Fish Oils and Cholesterol Metabolism 3. The Comparative Hypocholesterolemic Activities of Fish Oil and Vitamin A
Authors: Wood J. D. , Topliff J.
Published: April 2011

Certain fish liver oils, when present in the diet, prevented hypercholesterolemia in chicks produced by cholesterol feeding. The hypocholesterolemic activity of the oils was proportional to the amount incorporated into the diet. Vitamin A-enriched corn oil produced similar results but corn oil itself was without effect. It was concluded that vitamin A was responsible for 73 to 85% of the activity of the fish liver oil. The cause of the additional activity of the marine oils is at present unknown.
The Lake Trout of Lac la Ronge, Saskatchewan
Authors: Rawson D. S.
Published: April 2011

The lake trout, Salvelinus namaycush, of Lac la Ronge was studied in the years 1948 to 1959 using gill netting, tagging, creel census and sampling of the spawning run. The trout spawned on shallow rocky reefs in the first week of October, when water temperatures were about 10 °C (50°F). Of the spawning run, 82% were from 7 to 12 years old. Possibly 10% of the mature trout failed to spawn in any single year.Growth rate varied widely in individuals and the average rate produced, at 10 years, a trout of 26 inches (66 cm) fork length and weighing 8 lb (3.6 0kg). No difference was found between growth rates of males and females and there was no change in average growth rate during the 10-year study. However, trout in the main lake grew considerably faster during their first 5 years than those in the deeper, colder Hunter Bay. Thirty-three trout weighing from 30 to 43 lb were examined.Ciscoes, whitefish, ninespine sticklebacks and other fish made up 90% of the food of adult trout. The crustaceans Mysis and Pontoporeia were eaten in moderate quantities, especially by trout in their third and fourth years. Two cestode parasites were found in the intestine and the larvae of a third in the muscle of trout.The trout were widely scattered from break-up of ice in mid-May to late June. As the upper water warmed above 10 °C (50°F) they moved down and were concentrated in areas deeper than 20 m (65 ft) during July and August. As the water cooled they again spread into shallow water about mid-September. Of 429 tagged, 60 or 14% were recovered during the first, second and third years after tagging. Recoveries showed extensive movement throughout the lake and a moderate exchange between the main lake and Hunter Bay.In standard gill-net catches plankton-feeding and bottom-feeding fish outweighed piscivores by 3 to 1 in the main lake and 1.8 to 1 in Hunter Bay. Catch data suggest that the trout population was greater in 1958–59 than in 1948–49. The average size of trout caught and the year-class composition were unchanged after 10 years.By diverting commercial fishing from trout to whitefish the average commercial catch in the 10-year period has been maintained at 250,000 lb per year, as compared to 316,000 lb in the previous 30 years. The anglers' catch of trout now averages 30,000 lb per year and this could be doubled without exceeding the known capacity of the lake for trout production. The creel census shows no decrease in average size of trout caught, average catch per angler, and number of very large trout taken.
Temperature and the Biochemical Processes Occurring During Rigor Mortis in Cod Muscle
Authors: Fraser Doris I. , Punjamapirom Somsee , Dyer W. J.
Published: April 2011

not available
The Partial Desalting of Salted Cod
Authors: Crean P. B.
Published: April 2011

The results of small-scale experiments on the desalting of heavy-salted cod are presented. A method is proposed for a commercial desalting operation.
Diving and Photographic Techniques for Observing and Recording Salmon Activities
Authors: Ellis D. V.
Published: April 2011

Techniques have been developed for underwater observation and photographic recording of salmon activities that are useful in various kinds of behaviour studies. Scuba divers can approach salmon sufficiently closely under some conditions to permit clear observation. From tests made both above the surface and under water, an exposure chart has been prepared for salmon photography in rivers. Two examples are demonstrated. Colour film can be used, with appropriate filters, to render underwater objects in the colours they would have in air, or to give them untrue colours that assist in differentiating them from their background.
The Pollett Apron Seine
Authors: Elson P. F.
Published: April 2011

A two-man block seine about 16 feet (5 m) long has been modified for studying populations of small fish in the shallow, rapid salmon streams of eastern Canada. It is usually used in conjunction with DC electrofishing aids. The special feature of this seine is an extra strip of netting, the "apron", attached closely to the foot-line but extending back about 1 foot (30 cm) to a free edge over the main netting. This free edge of the apron is held about 4 inches (10 cm) above the main netting by wire gate frames fixed to the foot-line. Fish which would otherwise escape off the net are held in the space between main netting and apron. Construction and use are described in detail.
Migratory Behaviour of Juvenile Rainbow Trout, Salmo gairdneri, in Outlet and Inlet Streams of Loon Lake, British Columbia
Authors: Northcote T. G.
Published: April 2011

The marked differences in response to water current, exhibited by juvenile rainbow trout migrating into Loon Lake from its outlet and inlet streams, were studied both in the field and in experimental laboratory apparatus. All available evidence argued against genetically discrete outlet and inlet stocks, each maintaining different innate responses to water current. Difference in water temperature between streams was shown, in field and laboratory experiments, to regulate direction of juvenile trout migration through action on behaviour associated with downstream movement, maintenance of position and upstream movement.In laboratory experiments with cool (5 and 10 °C) flowing water, recently emerged fry rarely made contact with the stream bottom in darkness and exhibited much more downstream movement than in warm (> 14 °C) water. In cool streams of the Loon Lake system (daily mean consistently < 13 °C) large numbers of recently emerged fry moved downstream in darkness. Laboratory experiments indicated that combination of cool water (10 °C) and long day length (16 hours) induced downstream movement of fingerlings. In the field, fingerlings moved downstream largely in late spring and summer in cool streams of the Loon Lake system.In laboratory experiments with warm (15 and 20 °C) flowing water, recently emerged fry made frequent contact with the stream bottom in darkness and exhibited much less downstream movement than in cool (10 °C) water. In the warm outlet stream (daily mean in summer usually > 15 °C) recently emerged fry maintained position in darkness. Laboratory experiments suggested that short day length (8 hours) may facilitate maintenance of position exhibited by fingerlings in streams during late autumn and winter.Upstream movement of fry recorded in the field and tested in the laboratory was most pronounced in warm water (> 14 °C). Fingerlings subjected to rapid 5–degree (C) increases in water temperature in an experimental stream exhibited an immediate increase in upstream movement. Upstream movement in summer of large fry and fingerlings occurred only in the warm outlet stream; daily periodicity of upstream movement was positively correlated with sharp rises in water temperature.Evidence examined from four other widely separated stream systems indicated an environmental control of migration in juvenile rainbow trout similar to that demonstrated in the Loon Lake stream system. Possible mechanisms and interaction of factors controlling migratory patterns between and within streams are discussed. Significance of the predominant role played by temperature is considered.
A Method of Calculating Body Lengths from Otolith Measurements for Pacific Halibut and its Application to Portlock-Albatross Grounds Data between 1935 and 1957
Authors: Southward G. Morris
Published: April 2011

A change in growth rate of the halibut from the Portlock-Albatross grounds has occurred since the early 1930's. It is possible to measure this change in growth by studying the otoliths of fish taken by the commercial fishery in subsequent years. The calculation of body lengths from otolith measurements has provided a technique of reconstructing the growth patterns of each year-class. This method has been tested using the otoliths of recovered tagged halibut. The percentage deviations from average body length at each age demonstrate an increase in average length with time over the period 1920–1956. This increase is not exhibited among young fish of ages 1 through 4; it starts approximately with age 5 and continues throughout the older ages, where it is pronounced.
The Periodicity of Melosira islandica O. Müll. in Great Slave Lake
Authors: Lund J. W. G.
Published: April 2011

not available
New Records for Occurrence of the White-tip Shark, Pterolamiops longimanus (Poey), and the Dolphin, Coryphaena hippurus L., in the Northwest Atlantic
Authors: Tibbo S. N.
Published: April 2011

not available
A Note Concerning the Origin and Quantitative Distribution of Acid-soluble Phosphorus Compounds and Free Sugars in Fish Muscle
Authors: Tarr H. L. A. , Leroux M.
Published: April 2011

not available
Effect of Tetracycline Antibiotics on Objective and Subjective Fish Quality Tests
Authors: Boyd J. W. , Southcott B. A.
Published: April 2011

The effect of the antibiotics chlortetracycline and oxytetracycline on certain fish quality tests (viable bacterial count, trimethylamine nitrogen content and organoleptic rating) was evaluated. The formation of trimethylamine by the reduction of trimethylamine oxide in lingcod muscle was suppressed when chlortetracycline and oxytetracycline were used as preservatives in storage tests at 0 and 4 °C. Results of the three tests on antibiotic-treated samples showed poor agreement; reasonable agreement was obtained from the tests on control samples.
Migration and Feeding of the Gray Whale (Eschrichtius gibbosus)
Authors: Pike Gordon C.
Published: April 2011

Observations of gray whales from the coasts of British Columbia, Washington, and Alaska are compared with published accounts in order to re-assess knowledge of migration and feeding of the American herd. Source of material is mainly from lighthouses and lightships.The American herd of gray whales retains close contact with the shore during migration south of Alaska. Off Washington and British Columbia the northward migration begins in February, ends in May, and is at a peak during the first two weeks in April; the southward migration occurs in December and January, and is at a peak in late December. Northward migrants stop occasionally to rest or feed; southward migrants are travelling faster and appear not to stop to rest or feed during December and January. Gray whales seen off British Columbia, sometimes in inside protected waters, from June through October, probably remain in this area throughout the summer and fall months.Available evidence suggests that gray whales retain contact with the coast while circumscribing the Gulf of Alaska, enter the Bering Sea through eastern passages of the Aleutian chain, and approach St. Lawrence Island by way of the shallow eastern part of the Bering Sea. Arriving off the coast of St. Lawrence Island in May and June the herd splits with some parts dispersing along the Koryak coast and some parts continuing northward as the ice retreats through Bering Strait. Gray whales feed in the waters of the Chukchi Sea along the Siberian and Alaskan coasts in July, August and September. Advance of the ice through Bering Strait in October initiates the southern migration for most of the herd. In summering areas, in northern latitudes, gray whales feed in shallow waters on benthic and near-benthic organisms, mostly amphipods.There is no evidence to indicate that gray whales utilize ocean currents or follow the same routes as other baleen whales in their migrations. Visual contact with coastal landmarks appear to aid gray whales in successfully accomplishing the 5000-mile migration between summer feeding grounds in the Bering and Chukchi Seas and winter breeding grounds in Mexico.Reconstruction of the migration from all available data shows that most of the American herd breeds and calves in January and February, migrates northward in March, April and May, feeds from June through October, and migrates southward in November and December.
A Relationship Between Growth, Hatching and Spawning Season in Canadian Atlantic Herring (Clupea harengus L.)
Authors: Graham T. R.
Published: April 2011

not available
An Improved Method for the Preparation of Fish Protein Concentrate from Cod
Authors: Power H. E.
Published: April 2011

A high quality fish protein concentrate can be produced from cod fillets by extraction with suitable isopropanol–water mixtures. A process has been developed, on a pilot plant scale, for the production of high quality fish protein concentrate from skinned cod fillets by this method. It is white in colour and of soft texture and for all practical purposes tasteless and odourless. The analysis on a moisture-free basis, of a typical sample shows the following protein (N × 6.25), 96%; ash, 5%; lipids, 0.033%. The moisture remaining in the product after drying is approximately 4%. The yield of protein concentrate (approx. 4% moisture) is between 12 and 15%.