bluuebunny/crossref_metadata_2025 huggingface dataset:
Fertilized Eggs of the Butter Sole, Isopsetta isolepis, in Skidegate Inlet, British Columbia
Authors: Levings C. D.
Published: April 2011

not available
Evaluation of Fish Homogenates for Use as Substrates in Clostridium botulinum Type E Investigations
Authors: Boyd J. W. , Southcott B. A.
Published: April 2011

not available
An Occurrence of Ciliate Red Water in the Gulf of Maine
Authors: McAlice Bernard J.
Published: April 2011

not available
Adverse Conditions as Inhibitors of Ecdysis in the Lobster Homarus americanus
Authors: Stewart James E. , Squires H. J.
Published: April 2011

The molting incidence for male lobsters (Homarus americanus) subjected to a variety of conditions was compared with that for free male lobsters. The data show that for free western Newfoundland lobsters, molting reached the 90% level by the end of September. During the same period, mildly restrictive conditions reduced the molting incidence to 50% or less, and when lobsters held under these conditions were also tagged or marked the molting incidence was reduced to 30% or less. A reduction in molting, equivalent to or greater than that produced by tagging or marking plus mildly restrictive conditions, was achieved by highly restrictive conditions which enforced a high degree of association between lobsters. The diets used in these experiments did not appear to have any influence on the molting incidence. The data suggested that darkness plus starvation under highly restrictive conditions was even more inhibitory than any of the other conditions applied. Other light intensities tested under the highly restrictive conditions had no apparent effect on the molting incidence; however, stimulation of molting by light could have been negated by the inhibitory effects of this form of captivity.
Morphometrics, Distribution, Growth, and Maturity of Offshore Sand Launce (Ammodytes dubius) on the Nova Scotia Banks
Authors: Scott J. S.
Published: April 2011

A population of Ammodytes dubius occurs on the Nova Scotia banks, the fish being much larger than those reported previously for the species. The ranges of vertebral and anal fin ray numbers for A. dubius are extended. Research records of the launce, from catches and from stomach contents of predators, indicate that it is widely distributed over the banks throughout the year, but is concentrated in depths of 20–50 fath. Maturity data show that it is a winter spawner. A tentative growth curve, based on age–length determinations using otoliths, indicates that the growth pattern is similar to that of A. lanceolatus. The launce is shown to be an important item in the diet of cod and a constituent, in the egg or the adult stage, in the diets of many other commercially exploited fishes of the Nova Scotia banks.
La fraye d'une population d'éperlans géants, Osmerus eperlanus mordax, au lac Heney, Comté de Gatineau, Québec
Authors: Legault Roméo-O. , Delisle Claude
Published: April 2011

Two sympatric smelt populations inhabit Lake Heney, Gatineau County, Quebec. This study deals only with the population which we call "giant" but a brief discussion on "small smelt — large smelt" theory is included. The data were obtained from 1556 specimens collected with eight gillnets set up under the ice at one locality on Lake Heney, in February, March, and April 1967. The data permitted the determination of the time and site of spawning in the giant population. The time and site of spawning in the "dwarf" population was already known, and we found a marked difference in the spawning behavior and time of spawning of the two populations. The two populations are furthermore reproductively isolated. The sex ratio during the spawning period was closely followed and found to be similar to that of all other freshwater or marine smelts. A DeGiusti dredge, dragged along the bottom below the position of the gillnets immediately after the melting of the ice, permitted the collection of embryonic smelt eggs from a depth of 30–40 ft.The maturity index, relative fecundity, and intergonadal ratio were especially studied. Ovary weight at maturity represents in average one-quarter the total body weight, and testis weight one-fortieth the body weight. A 213-mm female lays an average of 42,460 eggs. The right ovary is 4.5 times smaller than the left one, and the right testis is on the average 3.8 times smaller than the left one.There is a direct relationship between total fecundity and length of mature females. This relation is expressed by the curve log E = 4.54 log L + k.
Âge et croissance du Maskinongé, Esox masquinongy, dans quatre lacs du Québec
Authors: Simard André , Magnin Étienne
Published: April 2011

Specimens were taken from two lakes where maskinonge is indigenous: Lake Saint-François (188 specimens) and Lake Saint-Louis (109 specimens), and from two others where it was introduced: Lake Saint-Joseph (44 specimens) and Lake Ouareau (12 specimens). The ages were determined from scales reading. Growth in length and in weight was identical for males and females from lakes Saint-François and Saint-Louis and there was no difference in growth observed in these same two lakes. Growth, however, was very different in lakes Saint-Joseph and Ouareau: during their 11th summer for instance, maskinonges from lakes Saint-François and Saint-Louis measured 1112 mm, and weighed 10,511 g whereas those from Lake Saint-Joseph measured 1024 mm and weighed 8854 g and those from Lake Ouareau measured 914 mm and weighed 5669 g. Our results are compared with those in the literature.
Influence of Temperature and Photoperiod on Guanine and Hypoxanthine Levels in Skin and Scales of Atlantic Salmon (Salmo salar) during Parr–Smolt Transformation
Authors: Johnston C. E. , Eales J. G.
Published: April 2011

The influences of temperature and photoperiod on the purine (guanine, hypoxanthine) levels in skin and scale silvery layers of Atlantic salmon at parr–smolt transformation were assessed by holding 2-year-old parr from December to June under four controlled temperature and photoperiod regimes: NLNT, 8LNT, NL3T, and 8L3T (where NL = naturally lengthening daily photoperiod; 8L = 8-hr daily photoperiod; NT = temperature held at 3 ± 1 C until mid-March and then rising to 14 C in June; 3T = temperature maintained at 3 ± 1 C throughout).From December through to March, levels of both purines increased under all four regimes. From April through to June purine levels continued to increase but were greater under NT than 8T regimes, showing that temperature influences purine deposition. Photoperiod changes did not modify purine levels appreciably. Other factors presumably influence silvering since under 8L3T (sustained "winter" conditions) purine levels more than doubled between December and June. The guanine/hypoxanthine ratio, higher for skin than for scale silvery layers, changed little seasonally and showed negligible dependence on temperature and photoperiod. Visual assessment of the extent of silvering correlated closely with measured purine levels. Increases in the fresh weight of fish were similar under all four regimes but a more pronounced decrease in the coefficient of condition occurred under NT regimes.
Two Methods of Describing the "Average" Vertical Temperature Distribution of a Lake
Authors: Sweers H. E.
Published: April 2011

The "average" vertical temperature distribution of a stratified freshwater lake can be obtained from a series of samples by various techniques. Two of these are described: computation of the average temperature at different levels and computation of the average depth of a number of isotherms. It is concluded that the latter technique can, under certain conditions, give a more realistic approximation of the observed temperature profiles, especially in the thermocline region.
A Review and Description of Caligus curtus Müller, 1785 (Caligidae: Copepoda), Type Species of its Genus
Authors: Parker R. R. , Kabata Z. , Margolis L. , Dean M. D.
Published: April 2011

The synonomy, known distribution, and hosts of Caligus curtus Müller, 1785 are reviewed. As a basis for comparison with its congeners, a description with illustrations is given. Homology of the thoracopods and functional morphology of the mouth cone and sternal furca are discussed.
Diel Limnetic Occurrence of Young Cottus asper in Two British Columbia Lakes
Authors: Sinclair D. C.
Published: April 2011

not available
Corrélation entre la structure rétinienne et l'habitat chez Stizostedion vitreum vitreum et S. canadense
Authors: Ali M. A. , Anctil M.
Published: April 2011

not available
Social Behavior among Juvenile Fall Chinook Salmon
Authors: Reimers Paul E.
Published: April 2011

not available
Distribution of Fatty Acids in Cod Flesh Lipids
Authors: Addison R. F. , Ackman R. G. , Hingley J.
Published: April 2011

Cod flesh lipids were separated by silicic acid chromatography into eight fractions, and the fatty acid distribution in five of these was examined by gas–liquid chromatography (GLC). As compared with the fatty acid composition of total flesh lipids, sterol esters contained less 16:0 but more 20:5ω3; ethanolamine phosphatides contained less 16:0, less 20:5ω3, but more 22:6ω3; serine phosphatides contained less 16:0 and less 20:5ω3 but more 18:0; and choline phosphatides had a fatty acid composition roughly similar to that of total flesh lipid but containing slightly more 16:0 and 20:5ω3 and less 22:6ω3. In fatty acid composition, the triglycerides more closely resembled liver lipid than any of the flesh lipid fractions.
Annulus Formation on Scales of Four Species of Coregonids Reared Under Artificial Conditions
Authors: Hogman Walter J.
Published: April 2011

Scales from known-age coregonids reared in the laboratory were examined to determine when annuli formed and to learn possible factors of their formation. Scales were taken monthly from marked fish for periods up to 21 months. Scales were also examined from fish that died and from preserved specimens of young-of-the-year for each species. Two marks formed on almost all scales each calender year. The stronger formed during March–April and the weaker in October–November. Both marks had all the usual characteristics of an annulus but the spring mark was considered the annulus and the fall mark an accessory check. The annulus formed during a period of constant temperatures and of little change in growth or increasing growth. The accessory check formed during a period of declining temperatures (1–5 degrees F, or 0.6–2.8 degrees C, per month) and of little change in growth or declining growth. Most fish grew throughout the winter; the only exceptions were one bloater (Coregonus hoyi) and several of the largest lake whitefish (C. clupeaformis). Fish were always given all the food they would eat to eliminate availability of food as a factor of mark formation. The temperature of the water during the winter (50 ± 0.3 F; 10.0 ± 0.2 C) did not arrest metabolic activity. The growth rate was related more closely to day length than to other variables examined.
Laboratory Experiments on the Orientation of the Adult American Eel, Anguilla rostrata
Authors: Miles S. G.
Published: April 2011

Adult American eels, Anguilla rostrata, caught on their spawning migration downriver, were filmed while in a circular tank, and the orientation of the eels was analysed by determining the direction of alignment of each eel in each frame of the time-lapse film. When allowed a view only of the sky, the eels oriented southward, in the direction of their supposed breeding area in the region of the Sargasso Sea. This southward orientation continued even if the eels were denied a view of the sky, provided they were subject to the diel rhythm of light–dark. Thus the eel seems capable of noncelestial orientation; the physical basis of this is not known.
Smolt Survival and Adult Utilization of Little Codroy River, Newfoundland, Atlantic Salmon
Authors: Murray A. R.
Published: April 2011

Between 1954 and 1961, seaward-migrating Atlantic salmon smolts were marked by the removal of their dorsal and adipose fins and released from the counting fence in the estuary of the Little Codroy River, Newfoundland, to determine their survival to, and utilization as, adults. Not all smolts were marked: in 1957 and 1958, about half, and in 1959, none were marked to assess the effects of marking on survival; in 1962, smolts were counted without being handled in a specially designed trap to assess the effects of handling on survival. A total of 61,394 smolts were finclipped; 523 marked adults (0.82% of the smolts marked) returned to the fence, and 876 marked adults (1.47%) were estimated to have been taken by the commercial fishery in Newfoundland and Labrador. In addition, there was an unknown but probably large number of grilse landed that did not get into commercial channels and so were not sampled. Five age-groups of smolts migrated, but two of these were scarce and only three were found among the adult survivors. These were age-2 smolts (1.79% of the smolts marked), age-3 smolts (2.43%), and age-4 smolts (1.64%). Three sea-age groups were represented among the recorded survivors: grilse (0.96% of the smolts marked), 2 sea-year salmon (1.21%), and 3 sea-year salmon (0.07%). About 62% of the recorded survivors were utilized by the commercial fishery, 4% by anglers on the Little Codroy, and the remaining 34% escaped and may have spawned. The commercial fishery is estimated to have taken 48% of the grilse (plus some unrecorded grilse), 75% of the 2 sea-year salmon, and 43% of the 3 sea-year salmon. The handicap created by the loss of the dorsal and adipose fins and defined by the ratio of the instantaneous mortality rates of marked and unmarked fish was estimated to be 1.10. Handling smolts was estimated to cause an immediate instantaneous mortality of 0.23. The overall average survival rate, conservatively adjusted, becomes 3.64%, that is, 2235 adult salmon would have survived from the migration of 61,394 smolts if they had not been handled and marked. However, if an estimate of unrecorded grilse be added, and a greater adjustment made for marking mortality, the survival rate becomes 9.42%. In addition to handling and marking, smolt survival also appears to have been affected by the size, age, and number of smolts migrating, as well as by the mark itself. Returns of Little Codroy smolts to the fence were lower than returns of salmon with missing adipose and ventral fins reported from several other streams.
Loss of Radioactivity During Storage of 14C-Labelled Phytoplankton on Membrane Filters
Authors: Wallen D. G. , Geen G. H.
Published: April 2011

not available
Reproduction of White Perch, Roccus americanus, in the Bay of Quinte, Lake Ontario
Authors: Sheri A. N. , Power G.
Published: April 2011

not available
Parasitism of the Toxin-Producing Dinoflagellate Gonyaulax catenella by the Endoparasitic Dinoflagellate Amoebophrya ceratii
Authors: Taylor F. J. R.
Published: April 2011

not available
Survival of Marked Lake Trout in Lake Manitou, Manitoulin Island, Ontario
Authors: Budd J. C. , Fry F. E. J. , Smith J. B.
Published: April 2011

Lake trout (491 in all), Salvelinus namaycush, planted as yearlings in Lake Manitou in 1952 were tagged at age VII when taken in trap nets during spawntaking operations. At the same time 259 native adult trout of unknown age were also tagged. In spawntaking operations in subsequent years tag numbers were noted for tagged fish recaptured and the fish returned to the lake after normal spawntaking. Both groups were estimated to have suffered a decrement of 25% per year. The lake trout planted were given a distinctive fin clip on planting so that comparisons of recaptures of tagged and untagged planted fish permitted estimates of the survival of the total plant. The mean annual mortality rate from the time of planting was also estimated at 25%. Trout planted later appeared to have suffered a similar mortality rate. Observations on planted lake trout of known age indicated that the peak age for first spawning in females was age VI. There is no predation by sea lamprey in Lake Manitou.
Degradation of DDT in Atlantic Salmon (Salmo salar)
Authors: Greer G. L. , Paim U.
Published: April 2011

As indicated by thin-layer chromatography, hatchery-reared Atlantic salmon parr degraded DDT, absorbed from aqueous suspensions, to DDE and TDE within 9 hr. DDT adsorbed on external surfaces of the salmon was not degraded.
Direct Estimation of a Fish Population Acoustically
Authors: Cushing D. H.
Published: April 2011

A method is described of estimating fish stocks by length-groups acoustically. Hake off southern Africa were recorded as individuals on the paper record of a Kelvin Hughes "Humber" echo sounder down to 350 fath. Signal strengths of single fishes were observed on the cathode ray tube and the target strengths of fishes are known; estimates of fish sizes were made. The signals were considered as being received from a mean angle (to the axis of transmission) in the volume insonified. Hence, average target strengths, average numbers/unit volume, and average heights above the sea bed were calculated.The echo survey made between Cape Town and Walvis Bay was expressed as numbers of fish/unit volume in a range gate of 1 or 4 fath above the sea bed. A length distribution of the hake stock was derived.
Two New Species of Gyrocotyle (Monogenea) from Hydrolagus affinis (Brito Capello) (Holocephali)
Authors: Land Jacob van der , Templeman Wilfred
Published: April 2011

Two new species of Gyrocotyle have been found in the intestine of the deepwater chimaera Hydrolagus affinis of the northwest Atlantic. Gyrocotyle had not previously been recorded from this host species.Descriptions are provided for ♂-mature and ♀-mature specimens of Gyrocotyle major n.sp. and ♂-mature specimens of Gyrocotyle abyssicola n.sp. The systematic status, distribution, and some host relationships of these species are discussed. Within the subgenus Amphiptyches, two groups of species are recognized: the urna-group, including G. major, and the confusa-group including G. abyssicola. Geographical variation is shown by G. major. Allometric growth of different parts of the body in G. major is described. These Gyrocotyle specimens are the largest yet recorded, G. major attaining a maximum length in our collection of 200 mm and G. abyssicola of 138 mm. The size of G. major increases with size of host.
Some Morphological and Biochemical Changes in Coho Salmon,Oncorhynchus kisutch, During Parr–Smolt Transformation
Authors: Vanstone W. E. , Markert J. R.
Published: April 2011

Growth rates and changes in some chemical constituents were investigated in laboratory-reared and wild coho salmon in the pre-smolt, smolting, and early post-smolt stages of their life cycles.Laboratory-reared pre-smolts of coho salmon continued to grow during fall and early winter but at an ever diminishing rate. During late winter, spring, and early summer, growth in both length and weight of these fish was exponential with time. In wild coho pre-smolts there was no apparent winter growth but, with the onset of warmer waters and longer day lengths in the spring, growth in both length and weight became exponential with time. Exponential growth continued in wild post-smolts held in seawater pens but at a slower rate than during smolting.It is postulated that the power b in the weight–length formula W = aLbis approximately 3.2 and that during smolting, when the fish are becoming more streamlined, the parameter a decreases from approximately 7.5 to about 6.2.Guanine levels in belly skin, which appeared to be related to lighting conditions and physiological state of the fish rather than to length or weight, increased during smolting to about 6 μg/mm2skin and remained at these levels.In pre-smolt laboratory-reared fish total lipid increased with increasing growth. With further weight increases during exponential growth, the weight of lipid remained relatively constant and the amount of lipid per unit weight decreased. A decrease in percent lipid did not occur in wild fish.Total moisture, dry material, and nitrogen were linearly related to weight in the size-range investigated, but a sharp inflection in each least-square fit line occurred for moisture and dry material at a fish weight of 15 g and for total nitrogen at 7.5 g. These shifts in composition were related to fish size rather than to age, environment, or physiological state. During exponential growth, moisture, dry material, and nitrogen increased with increasing weight but whereas moisture increased at a slower rate than weight, solids and nitrogen increased more rapidly.
Distribution of 65Zn In Tissues of Two Marine Crustaceans Determined by Autoradiography
Authors: Cross F. A. , Fowler S. W. , Dean J. M. , Small L. F. , Osterberg C. L.
Published: April 2011

In the benthic amphipod Anonyx sp., and the euphausiid Euphausia pacifica Hansen, 65Zn accumulated from seawater was shown by autoradiography to be localized predominantly in the exoskeleton and interstitial spaces of the myofibrils. Also, the gut and hepatopancreas of Anonyx sp. and the eye of E. pacifica contained 65Zn. The presence of 65Zn in crustacean exoskeletons may affect the efficiency of transfer of 65Zn through the food web and the vertical distribution of 65Zn in the Pacific Ocean along the Oregon coast.
Abnormal Cessation of Growth in a Herring Otolith
Authors: Hourston A. S.
Published: April 2011

not available
A Rapid Marking Technique for Identification of Individual Fish
Authors: Owens Eben L. , Gebhardt Gary A.
Published: April 2011

not available
Age, Growth, Food, and Yield of the White Sturgeon (Acipenser transmontanus) of the Fraser River, British Columbia
Authors: Semakula S. N. , Larkin P. A.
Published: April 2011

For white sturgeon taken incidentally in the salmon gillnet fishery in the Fraser River during the summer of 1962, pectoral fin ray sections indicated that over three-quarters were fish aged 9–16 years. Gillnets for salmon apparently select sturgeon over a size range between 30 and 60 inches. Back-calculation of size attained at previous ages indicated that after attaining a length close to 20 inches by age 5, the sturgeon grow about 2 inches per year to about age 25. Limited data from pectoral fin ray sections suggest that age at first spawning is from 11 to 22 years for males, and from 11 to 34 for females. Subsequent spawning is apparently at intervals of 4–9 years. Fraser River sturgeon are more piscivorous than has been recorded for white sturgeon and other sturgeon species elsewhere, about one-half of the stomachs containing fish, especially eulachons. The age distribution in the catch, though biased by selection, was used to estimate rates of natural and fishing mortality. The eumetric fishing curve suggests that present yield could be increased by a greater size at first capture, particularly if the natural mortality rate is as low as 0.05. The history of the sturgeon fishery suggest that sustainable yield could exceed 100,000 lb per year. The commercial landings in recent years average 30,000–40,000 lb. The sport fishery may take an additional 20,000–30,000 lb. Sustained yield in the circumstances of the present fishery could be 80,000 lb per year, about 25% more than the present catch. Some recommendations are made for management, stressing the importance of protection of an annual spawning population of 300–600 females.
Effect of Sublethal DDT on the Lateral Line of Brook Trout, Salvelinus fontinalis
Authors: Anderson John M.
Published: April 2011

The lateral line nerve of brook trout responds to an abrupt low-frequency pressure wave, generated by a falling drop of water hitting the water surface, by a relatively short high-frequency burst of large spikes. The burst duration has a negative temperature coefficient. Exposure of trout for 24 hr to DDT, ranging from 0.1 to 0.3 ppm, renders the lateral line nerve hypersensitive to the experimental stimulus; in particular there is a marked increase, especially at the colder temperatures, in the negativity of the temperature coefficient of the burst durations. The results are discussed in general terms, as well as specifically in relation to other laboratory work which shows that sublethal DDT affects behavioural responses of fish to temperature.
Metabolism of the Radioisotope 65Zn in the Freshwater Mussel Anodonta californiensis
Authors: Pauley Gilbert B. , Nakatani Roy E.
Published: April 2011

not available
Simplification of a Method of Computing Recruitment Rates
Authors: Allen K. Radway
Published: April 2011

not available
Reproductive Isolating Mechanisms of the Blackspotted Stickleback, Gasterosteus wheatlandi
Authors: Reisman Howard M.
Published: April 2011

not available
Localization of Creatine Kinase in the Starch–Gel and Moving-Boundary Electrophoretic Patterns of Fish Muscle
Authors: Gosselin-Rey C. , Hamoir G. , Scopes R. K.
Published: April 2011

not available
Lobsters from 95 Fath Deep off St. John's, Newfoundland
Authors: Squires H. J. , Ennis G. P.
Published: April 2011

not available
Surface Phosphate and Silicate Distributions in the Northeastern Pacific Ocean
Authors: Park P. Kilho , Hager Stephen W. , Pirson Jacques E. , Ball David S.
Published: April 2011

not available
Estimating Mean Weight from Length Statistics
Authors: Pienaar J. V. , Ricker W. K.
Published: April 2011

not available
Possible Effects of the Harbour Seal Bounty on Codworm Infestations of Atlantic Cod in the Gulf of St. Lawrence, the Strait of Belle Isle, and the Labrador Sea
Authors: Wiles Michael
Published: April 2011

not available
Lakeward Migration of Young Rainbow Trout (Salmo gairdneri) in the Upper Lardeau River, British Columbia
Authors: Northcote T. G.
Published: April 2011

Lakeward migration of rainbow trout fry was studied in the upper Lardeau River, where the young emerge from a spawning area immediately below the outlet of Trout Lake utilized by large trout from Kootenay Lake, about 56 km downstream. Most fry move downstream towards Kootenay Lake shortly after emergence; however, some, particularly later in the emergence period, move upstream into Trout Lake. Field observations and experiments suggest that water temperature may be important in inducing different responses to water current in these fish, but may not play such a predominant role or operate at the same levels as proposed earlier for control of young trout migration in the Loon Lake system.
Hypoxial Stress Prior to Emergence and Competition Among Coho Salmon Fry
Authors: Mason J. C.
Published: April 2011

Competition among coho salmon fry in stream aquaria supplying natural drift was found to reflect the history of exposure of eggs and resulting fry to dissolved oxygen concentration prior to emergence. Size disparities induced by differential hypoxial stress were amplified with time, and fry that had been exposed to the most severe hypoxial conditions were most prone to emigrate. Most emigrants placed in an initially vacant, replicate system remained there, grew rapidly, and became as large as, or larger than, nonemigrants. Size of former emigrants reflected enhanced feeding opportunity due to less competition for food and space in the replicate system. Competition was referred more precisely to hypoxial history by using net production. A replicate population fed hatchery food provided a comparison. When exposed to the stream aquaria, this population substantiated the previous findings. Diel cycles of activity and aggression peaked at dawn and dusk, and were related to competition for food and space. The ecological significance of the results is discussed with particular regard to competition for food and space, and the effect of a size-related social order that put smaller individuals at a disadvantage.
Some Metabolic Effects of Bacterial Endotoxins in Salmonid Fishes
Authors: Wedemeyer Gary , Ross A. J. , Smith Lynwood
Published: April 2011

Coho salmon (Oncorhynchus kisutch) and rainbow trout (Salmo gairdneri) were highly resistant to endotoxins from both Escherichia coli and Aeromonas salmonicida (a fish pathogen) at 14 and 18 C.This resistance was investigated with liver tryptophan pyrrolase, liver glycogen depletion in vitro, and the arterial blood pressure as indicators. Liver glycogen depletion was accelerated by both endotoxins, but there was no significant cardiovascular response or effect on liver tryptophan pyrrolase activity. Since the cardiovascular effects of histamine were also limited, it was concluded that the metabolic effects of bacterial endotoxins in salmonids are qualitatively different from those of the higher vertebrates.
Allometric Weight–Length Regression Model
Authors: Pienaar L. V. , Thomson J. A.
Published: April 2011

Two methods of fitting the allometric weight–length relationship are described, one involving the common logarithmic transformation of variables in a multiplicative model and the other assuming an additive nonlinear model and general nonlinear estimation procedures. Differences in the assumptions involved in the two methods are emphasized and the practical significance of the different methods is demonstrated with the aid of a sample problem. A number of procedures are suggested to compensate for possibly unjustified assumptions.
Comparison between Gompertz and von Bertalanffy Curves for Expressing Growth in Weight of Fishes
Authors: Silliman R. P.
Published: April 2011

The two types of curves were fitted to empirical weights-at-age for four commercially important species: sardines, haddock, lake trout, and chum salmon. For the range of observed data, both curves fit the empirical points well, and seem almost indistinguishable on this basis. The upper asymptotic limit of weight, however, was higher for the von Bertalanffy than for the Gompertz, in all four examples. Fitting complexity is similar for both types of curves, but the Gompertz does not require the assumption of cubic length–weight relation implicit in the Beverton–Holt treatment of the von Bertalanffy.
Identification of Northern Pike and Muskellunge from Axial Skeletons, Scales, and Epipleurals
Authors: Crossman E. J. , Casselman John M.
Published: April 2011

Grooves and knobs on the vertebrae, ratio of length and width of scales, and ratio of lengths of rami of epipleural bones enabled us to separate northern pike and muskellunge in mutilated specimens, stomach contents, and archaeological material.
Aspects of Estimating Zooplankton Production from Phytoplankton Production
Authors: McAllister C. D.
Published: April 2011

Primary productivity and zooplankton data from Ocean Station P are used to compare estimates of phytoplankton and herbivore production calculated on the assumption of continuous grazing by the animals with estimates obtained on the assumption of three different types of nocturnal grazing. Effective plant production, that corrected for the effects of grazing on the size of the phytoplankton stock and hence on the magnitude of the plant respiratory loss, was less than the measured production and was least under the assumption of continuous grazing. The small differences in effective production resulting from the choice of different grazing schemes resulted in large differences in estimates of secondary production. The relative effect of assuming different grazing schemes on the estimate of secondary production varied markedly with zooplankton respiration and with the phytoplankton growth rate.
Distribution of Fishes of Southern Alberta
Authors: Henderson Nancy E. , Peter Richard E.
Published: April 2011

Detailed distributions are given for 35 species of fish collected in southern Alberta. These include the first record of Moxostoma anisurum in Alberta, new records in the South Saskatchewan River drainage, and extensions of the known ranges of a number of species within the province. Records reported by earlier investigators are included with the aim of providing a complete account of the distributions of fishes in this region.
Culture Methods and Effects of Temperature and Salinity on Survival and Growth of Dungeness Crab (Cancer magister) Larvae in the Laboratory
Authors: Reed Paul H.
Published: April 2011

Recent interest in causes of Dungeness crab (Cancer magister) population fluctuations led to a study of temperature and salinity effects on survival and growth of zoeae.Preliminary work developed methods for culturing larvae in flasks with good survival. A comparison of survival of larvae fed two different diets showed the nauplii of the barnacle Balanus glandula and larvae of the bay mussel Mytilus edulis were suitable and unsuitable food organisms, respectively.The optimum ranges of temperature and salinity for laboratory-cultured C. magister zoeae were 10.0–13.9 C and 25–30‰, respectively. Zoeal survival was not significantly affected by temperatures and salinities approximating ocean ranges of these variables off the Oregon coast during the larval period. The growth rate of C. magister zoeae was directly related to temperature, but salinities that favored survival did not appear to affect the zoeal growth rate.
Effect of Woodland Clearance on Stream Temperature
Authors: Gray J. R. A. , Edington J. M.
Published: April 2011

A study was made of the temperature characteristics of a stream which flowed first through open fields and then through woodland. When the woodland was felled, that section of the stream showed a marked rise in summer temperature. It is argued that the presence or absence of tree shading can be the decisive factor in determining the temperature of small streams.
A Study of Major Cations, Osmotic Pressure, andpH in Seminal Components of Atlantic Salmon
Authors: Hwang P. C. , Idler D. R.
Published: April 2011

Certain properties of semen, spermatozoa, and seminal plasma of Atlantic salmon were investigated to facilitate the development of an extender for the cryo-preservation of sperm. The seminal plasma of 10 fish had an average pH of 8.25, an osmotic pressure of 232 milliosmols, and contained 237, 86, 5.2, and 2.2 mg/100 g respectively of Na+, K+, Ca++, and Mg++. The corresponding values for spermatozoa were 84, 298, 1.5, and 18.7. Storage of semen at 2 C caused an increase of Na+and Ca++and a decrease of K+and Mg++in spermatozoa. Subsequent incubation in glucose solution did not restore ion balance in salmon spermatozoa as it did in dog spermatozoa. The results for salmon are compared with limited data for Atlantic cod.
Lethal Temperatures for Great Lakes Rainbow Trout
Authors: Bidgood B. F. , Berst A. H.
Published: April 2011

Samples of progeny from wild rainbow trout (Salmo gairdneri) homing to four widely separated Great Lakes watersheds, when incubated and reared under similar conditions and acclimated to 15 C, did not differ in tolerance to upper lethal temperatures. The size of the individual fish under test did not affect the resistance time. The similar response of the four samples to upper lethal temperatures complements the conclusions previously reported from phenotypic observations of wild and cultured trout from the same four watersheds.
Effects of Size-Selective Mortality and Sampling Bias on Estimates of Growth, Mortality, Production, and Yield
Authors: Ricker W. E.
Published: April 2011

Size-selective mortality decreases or increases the actual and back-calculated lengths of an age-group, while at the same time altering the shape and variance of its length frequency distribution only slightly or not at all. An index of intensity of selection (r) can be calculated from the difference in computed length (d) between the penultimate annulus at age n and the terminal annulus at age n−1, together with the standard deviation in length (s); it is r = 1.349d/s, and represents the difference in mean instantaneous mortality rate between the two halves of the frequency distribution. Instantaneous rates of increase in weight can be computed from length data by multiplying the difference between the natural logarithms of length 1 year apart by the exponent in the weight–length relationship. When there is size-selective mortality, the difference between the rate (GX) based on observed weights in successive years differs from the true rate (G) based on the terminal length differences computed from scales. Similarly the instantaneous rate of decrease in numbers (Z) differs from the rate of loss of weight or ponderal mortality rate (ZW). It is found that G−GX = ZW−Z. "Lee's phenomenon" may be caused by selective mortality or by biassed sampling. Unlike selective mortality, biassed sampling produces only positive Lee's phenomenon (back-calculated lengths from older fish less than those calculated from younger fish), regardless of whether it is the smaller or the larger fish that are favoured by the sampling gear. The use of incorrect growth rates can lead to rather large errors in estimates of production of a stock. Errors in computation of yield, due to using numerical instead of ponderal mortality rates, tend to be much smaller.
Feeding Behaviour of Cod (Gadus morhua)
Authors: Brawn V. M.
Published: April 2011

Cod 5–90 cm long in captivity used sight to detect food in midwater. Movement of food stimulated feeding but was not essential when feeding on familiar foods. Adult cod could detect and capture falling food down to 2 mm in diameter. Large pieces of food on the bottom were found by sight but smaller pieces were taken after being detected by taste buds on the trailing barbel and pelvic fin rays. Cod were able to detect odours from many live, intact algae, invertebrates, and fish. Food below gravel or stones was located by smell and uncovered by carrying away gravel in the mouth or by rolling stones aside with the head. Food covered by sand was not found. Some live food was captured in the dark. Cod groups fed more effectively than single cod as food deeply buried was uncovered by several fish digging in the same place; food too large for one fish was pulled apart between fish and feeding behaviour by one fish attracted others to the vicinity of food. Thus shoaling of cod may be advantageous to the species by enabling more food to be obtained from a given area.Larval cod reared from eggs first fed 4 days after hatching. Moving particles were followed by eye movements and captured by swimming forward and snapping if the particles moved in front of the head. Eight days after hatching the cod larvae began to feed on fine stationary particles by removing them from the respiratory water flow.
Structure de la rétine chez quelques téléostéens marins du plateau continental
Authors: Anctil Michel
Published: April 2011

A detailed study of retinal structure in 20 pelagic and demersal species of fish indicates that valid correlations exist among the photic environment, activity of the fish, and its visual apparatus. Generally, the relative abundance of rods is inversely proportional to that of the cones. This relationship exists inter-specifically in the same retinal region and intra-specifically in different parts of the same retina. The topographical specialization of cones, or formation of a retinal area, is high in active pelagic species (Clupea, Alosa), less in sluggish demersal fish, and absent in the shore fish Tautogolabrus where a specific ocular behavior compensates. The resolving power of the retinal area is high in pelagic and shore fish, but is lower in demersal species. The distribution of the cone types within a retina suggests that photic sensitivity increases from single to quadruple cones. Cone arrangements are more refined in active species likely to detect fast-moving preys. Inter- and intra-specifically, the development of the inner retinal layers parallels that of the cones. The functional importance of the resolving power appears to rely heavily on the extent of summation at the bipolar and ganglion cell layer level. The cone/rod and single/double cone ratios are proportional to the abundance of bipolar neurons in the species examined.
Isolation and Preliminary Characterization of Some Aeromonas salmonicida Bacteriophages
Authors: Paterson W. D. , Douglas R. J. , Grinyer I. , McDermott L. A.
Published: April 2011

Bacteriophages for Aeromonas salmonicida were isolated from water and mud samples taken from 13 of 19 trout hatcheries and ponds examined in southern Ontario. Nine of the 13 locations were known to have histories of furunculosis disease. The bacteriophages studied formed three serological groups and two distinct morphological types. Phages of serological groups I and II possessed similar morphology; those of group III resembled the coli T-even phages. All possessed complex symmetry consisting of a head and tail with a contractile tail sheath. Latent periods of the phages ranged from 35 to 95 min and average burst sizes from 21 to 193. A group I phage and a group III phage had [Formula: see text] values of 351 and 1000, respectively.
Age Determination in the White Sucker
Authors: Beamish R. J. , Harvey H. H.
Published: April 2011

The purpose of this study was to test the reliability of the scale method for determining the age of white suckers. To do so, an alternative method of "aging" was explored, using sections cut from the first four rays of the pectoral fin. Two hundred and fifty white suckers were tagged, and a piece of one pectoral fin was removed before they were released. A year later, 25 were recaptured, and the rays of the remaining pectoral fin were aged. Of the recaptures, 22 showed clearly the addition of one annulus.Having confirmed the fin-ray method, the age of another 157 suckers was determined by scales and fin rays and compared. The results indicated the scale method was reliable, in this population, until the fish reach an age of 5 years. Beyond 5 years there was not close agreement between scale and fin ages. After 8 years, age as determined by scales was invariably less than from fin rays, and sometimes was in error by as much as 5 years.
Corpuscles of Stannius and Renal Physiology in the Eel (Anguilla rostrata)
Authors: Butler D. G.
Published: April 2011

In freshwater eels there is a significant correlation between glomerular filtration rates (GFR) and urine flow rates suggesting that changes in GFR rather than tubular water reabsorption lead to the major adjustments in urine flow rates accompanying changes in environmental salinity.Removal of the corpuscles of Stannius was not followed by a significant change in GFR indicating that an adequate (normal) effective filtration pressure is independent of a corpuscular pressor substance.In 8 of 17 Stanniectomised eels urine flow rates exceeded GFR demonstrating that, under these experimental conditions, eel renal tubules secrete water.Multiple tissue electrolyte changes followed Stanniectomy; the 75% increase in the plasma calcium concentration is of particular interest. This increase was probably due to a reduction in the net rate of calcium deposition in bone and not to a change in the renal handling of calcium.
Age Determination from Scales of Chum Salmon (Oncorhynchus keta)
Authors: LaLanne John J. , Safsten Gunnar
Published: April 2011

The methodology of age determination from scales of chum salmon (Oncorhynchus keta) is reviewed. Scales from chum salmon caught in the North Pacific Ocean and streams of North America were studied. Most annuli are of two main types: a poorly formed circulus usually "cut over" by the first circulus of new growth, and what appears to be a normal circulus in the annual ring. The annulus of type 1 may be independent of the annual ring. Annuli may be at the anterior or posterior margins of the annual ring, or within it. Direct evidence that annuli are recognizable age indices was obtained from scales of marked fish.An average of 98% of the age determinations by three scale readers agreed with the known age of the fish. The time of annulus formation or start of new growth extends from as early as March to the end of June and possibly to the end of July. The annual ring begins to form near the end of the season (as early as August) or when new growth occurs in the spring or summer. Sometimes an annual ring is not formed. Scales taken from various parts of the body had the same number of annuli.
Age and Vision as Factors in Bottom Colour Selection by Rainbow Trout, Salmo gairdneri
Authors: Kwain Wen-hwa , MacCrimmon Hugh R.
Published: April 2011

Rainbow trout exposed in a circular tank to a choice of black or white bottom at a light intensity of 10−2 lux were randomly distributed until the age of 14 months at which time a significant preference for black began and became more pronounced with increasing age.Groups of fish (18–24 months of age) with normal eyes, without eye lenses, and lacking eyes, were held in total darkness and at 10−2, 10, and 200 lux. In total darkness all groups were randomly distributed and quiescent. Fish without eye lenses selected black at all visible light intensities and acted similarly to normal fish at 10−2 lux. Fish lacking eyes were randomly distributed and more-or-less inactive at all intensities.The eye is essential for bottom colour discrimination and behavioural patterns occurring in normal trout exposed to different light intensities.
First Record of Occurrence of the Northern Redbelly Dace, Chrosomus eos, within Prince Edward Island
Authors: Woronecki David E.
Published: April 2011

Four specimens of Chrosomus eos were collected from the Morell River, Kings County, Prince Edward Island. Its occurrence within the Province has not been previously recorded. The distribution of this species within the neighboring provinces is noted.
The Sporozoa: With Particular Reference to Infections in Fishes
Authors: Stunkard Horace W.
Published: April 2011

A critical review of the Sporozoa is presented with consideration of changes in taxonomic arrangement as different morphological and developmental features have influenced opinion on systematics in the group. Infections of fishes receive primary attention, especially those produced by members of the Microsporidia. Although chiefly parasites of invertebrates, certain species cause severe infections in fishes. The bionomics, life cycles, and taxonomy of these species are still equivocal.
A New Trematode of the Genus Lepidophyllum (Digenea: Steganodermatidae) from a Cottid Fish, Hemilepidotus hemilepidotus
Authors: Arai Hisao P.
Published: April 2011

Lepidophyllum cameroni n.sp., parasitic in the urinary bladder of a cottid fish, Hemilepidotus hemilepidotus (Tilesius), from Burke Channel, British Columbia, is described and illustrated. The genus Paralepidophyllum Yamaguti, 1934, is reduced to synonymy with Lepidophyllum Odhner, 1902, Lepidophyllum pyriforme (Yamaguti, 1934) resulting as a new combination.
Observations on the Seasonal Changes of the Parasite Fauna of Yellow Perch (Perca flavescens) from the Bay of Quinte, Lake Ontario
Authors: Tedla Shibru , Fernando C. H.
Published: April 2011

The seasonal changes in incidence and intensity of infestation of yellow perch, Perca flavescens, by adult and larval parasites, both external and internal, were studied over a period of 1 year. Eight species of parasites were numerous enough to permit analysis of seasonal dynamics. Bunodera luciopercae and Echinorhynchus salmonis showed a high infestation in the fall and declined gradually to zero by late summer. New infestation occurred in early fall. Protocephalus pearsei showed the highest incidence in summer and a lower level during the rest of the year without any marked fluctuations. The intensity of infestation remained relatively constant throughout the year. Ergasilus confusus reached its peak of incidence in the summer, declined through the fall and winter, and began increasing in spring. Intensity of infestation showed parallel changes. In February, however, both incidence and intensity were high. Diplostomulum huronense showed a high intensity of infestation in November. The incidence remained fairly constant throughout the rest of the year. Urocleidius adspectus showed no seasonal variability as regards incidence but the intensity of infestation was highest in August and September. Contracaecum spiculigerum showed no distinct seasonal changes in incidence or intensity. Glochidial infestation reached a high intensity in July. This was due to the glochidia of Lampisilis radiata siliquoidea.
Two New Species of Monogenetic Trematodes (Trematoda: Monogenea) from Nasal Cavities of Catostomid Fishes
Authors: Dechtiar Alex O.
Published: April 2011

Pellucidhaptor catostomi n.sp., recovered from the nasal cavities of longnose suckers, Catostomus catostomus (Forster), and Pellucidhaptor nasalis n.sp., recovered from the same site in white suckers, Catostomus commersoni (Lacépède), are described.