bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simple Method for Predicting the Capacity of a Lake for Development Based on Lake Trophic Status
Authors: Dillon P. J. , Rigler F. H.
Published: April 2011

A general technique is presented for calculating the capacity of a lake for development based on quantifiable relationships between nutrient inputs and water quality parameters reflecting lake trophic status. Use of the technique for southern Ontario lakes is described. From the land use and geological formations prevalent in a lake’s drainage basin, the phosphorus exported to the lake in runoff water can be calculated, which, when combined with the input directly to the lake’s surface in precipitation and dry fallout, gives a measure of the natural total phosphorus load. From the population around the lake, the maximum artificial phosphorus load to the lake can be calculated and, if necessary, modified according to sewage disposal facilities used. The sum of the natural and artificial loads can be combined with a measure of the lake’s morphometry expressed as the mean depth, the lake’s water budget expressed as the lake’s flushing rate, and the phosphorus retention coefficient of the lake, a parameter dependent on both the lake’s morphometry and water budget, to predict springtime total phosphorus concentration in the lake. Long-term average runoff per unit of land area, precipitation, and lake evaporation data for Ontario provide a means of calculating the necessary water budget parameters without expensive and time-consuming field measurements. The predicted spring total phosphorus concentration can be used to predict the average chlorophyll a concentration in the lake in the summer, and this, in turn, can be used to estimate the Secchi disc transparency. Thus, the effects of an increase in development on a lake’s water quality can be predicted. Conversely, by setting limits for the "permissible" summer average chlorophyll a concentration or Secchi disc transparency, the "permissible" total phosphorus concentration at spring overturn can be calculated. This can be translated into "permissible" artificial load, which can then be expressed as total allowable development. This figure can be compared to the current quantity of development and recommendations made concerning the desirability of further development on the lake.
Blood Oxygen Dissociation Characteristics of the Winter Flounder, Pseudopleuronectes americanus
Authors: Hayden Jonathan B. , Cech Jr. Joseph J. , Bridges David W.
Published: April 2011

Oxygen dissociation curves were determined for winter flounder (Pseudopleuronectes americanus) blood at 5, 10, and 15 C, and [Formula: see text], 8, and 24 mm Hg. Half-saturation tensions (P50’s) and blood oxygen capacities were measured and showed significant Bohr and Root effects. Calculations of Hill’s constant, n, implied no heme-heme interaction in the flounder hemoglobin. The apparent heat of oxygenation, ΔH, was calculated to be smaller than that in most teleostean hemoglobins. This small temperature effect, together with the modest slope of the hyperbolic oxygen dissociation curves, indicate a capacity to live in waters exhibiting a fairly broad range of temperatures and dissolved oxygen concentrations.
Relation of Water Temperature to Flexibacter columnaris Infection in Steelhead Trout (Salmo gairdneri), Coho (Oncorhynchus kisutch) and Chinook (O. tshawytscha) Salmon
Authors: Holt R. A. , Sanders J. E. , Zinn J. L. , Fryer J. L. , Pilcher K. S.
Published: April 2011

The effect of water temperature upon mortality from experimental infection by Flexibacter columnaris and on mean time to death was investigated in juvenile steelhead trout (Salmo gairdneri), coho salmon (Oncorhynchus kisutch), and spring chinook salmon (Oncorhynchus tshawytscha). Eight temperatures increasing from 3.9 to 23.3 C (39 to 74 F) by increments of 2.8 C (5 F) were studied. Fish were infected by the direct contact method whereby a suspension of the pathogen was added to the water. It was found that at temperatures of 9.4 C (49 F) and below, no deaths due to the experimental infection with F. columnaris occurred. At 12.2 C (54 F) mortality varied from 4 to 20% among the three species, and increased progressively with increasing temperature to 100% in steelhead trout and coho salmon at 20.5 C (69 F), and 70% in chinook salmon at that temperature. With all three salmonid species, an inverse linear relationship was found between water temperature and the log10 of the mean number of days from exposure to death. This means that as the temperature increased above 12.2 C (54 F), the disease process was progressively accelerated, resulting in a minimum time to death at 20.5 or 23.3 C (69 or 74 F) and a maximum at 12.2 C (54 F). The results indicate that under the conditions of these experiments, columnaris disease in salmonids was completely suppressed by water temperatures of 9.4 C (49 F) or below.
Experimental Observations on the Effects of Predation by Goldfish (Carassius auratus) on the Zooplankton of a Small Saline Lake
Authors: Archibald Chris P.
Published: April 2011

The short-term effects of various intensities offish predation on zooplankton communities were examined. Field studies indicated that fish predation was, as expected, size-selective: in the presence of fish, size distributions of the principal prey, Daphnia pulex, were skewed toward the smaller size-classes and the minimum size of egg-bearing D. pulex was also smaller. Fecundity of Diaptomus ashlandi, and probably also of Daphnia pulex, was greater with fish present. This caused the abundance of these two dominant species to increase initially with increasing predation. Subsequently, the species declined at higher predation levels in order of their interest to fish, with large D. pulex[Formula: see text] declining before small D. pulex (< 1.35 mm) and both groups doing so at lower predation levels than Diaptomus ashlandi.
Respiration and Chemical Composition of Pleuroncodes planipes (Decapoda: Galatheidae): Energetic Significance in an Upwelling System
Authors: Smith Jr. K. L. , Harbison G. R. , Rowe G. T. , Clifford C. H.
Published: April 2011

The energetic importance of the galatheid crab, Pleuroncodes planipes, was examined in the California Current off Baja California during April 1973. Respiration of Pleuroncodes ranged from 132 to 408 μl O2 h−1, which was equivalent to 404–728 μl O2 g ash free dry wt−1 h−1. Analyses of Pleuroncodes revealed that water, ash, protein, lipid, and chitin constituted 84, 7, 3.5, 0.7, and 2.8% of the total weight, respectively. These analyses give a mean caloric content of 1700 ± 430 cal. Pleuroncodes is a dominant functional component of the upwelling ecosystem in the California current and is comparable to the anchovy, Engraulis ringens, in the Peru upwelling ecosystem.
Selection by Brook Trout (Salvelinus fontinalis) and Juvenile Atlantic Salmon (Salmo salar) of Shade Related to Water Depth
Authors: Gibson R. John , Power G.
Published: April 2011

Salmon parr and small brook trout were observed in two stream tanks providing choices of cover. One tank was shallow (24–29 cm) and the other deep (43–50 cm). In the shallow tank brook trout occurred most frequently in shade. When salmon were the sole species, they were most frequently in shade, but were mostly away from shade in the presence of trout. This selection for shade was not evident by either species in the deep tank.
Terminology of Intervals in Fish Development
Authors: Balon Eugene K.
Published: April 2011

The intervals in fish ontogeny are once more defined and standard names proposed for each. Names such as fry, prelarva, postembryonic stage, free-swimming stage, etc. are discouraged and specific terms — cleavage egg, embryo, eleutheroembryo, protopterygiolarva, and pterygiolarva or alevin, juvenile, adult, and senescent fish — are suggested instead.
Fish Immunology.
Authors: Pauley Gilbert B.
Published: April 2011

not available
Seasonal Shifts in the Spawning Site of a Northeast Pacific Intertidal Fish
Authors: Marliave Jeffrey B.
Published: April 2011

In Barkley Sound, Vancouver Island, Canada, the spawning of the black prickleback, Xiphister atropurpureus, occurs during winter on rocky beaches protected from wave action. However, during spring, spawning occurs on rocky beaches of increasing exposure. This species spawns only under boulders with pebble, small rock, or shell substrates. Coincident reduction of wave action and increases in temperature probably cause the seasonal shift in the spawning site of this stichaeid.
Mercury and Iron Uptake by Cytosomes in Mantle Epithelial Cells of Quahog Clams (Mercenaria mercenaria) Exposed to Mercury
Authors: Fowler Bruce A. , Wolfe Douglas A. , Hettler William F.
Published: April 2011

Specimens of the quahog clam Mercenaria mercenaria were placed in sea water containing mercury (Hg++) concentrations of 0.1, 1,and 10 parts per million (ppm) for 6 days. A dose-related increase of electron dense cytosomes was observed by electron microscopy in mantle tentacle epithelial cells of mercury-treated clams. Energy dispersive X-ray microanalysis of these cytosomes disclosed the presence of high iron concentrations in relation to mercury. Analysis of mantle fringes from the same clams by atomic absorption spectroscopy showed marked changes in tissue iron levels of mercury-treated clams in comparison to controls.
Effect of Dietary Sodium Chloride on Growth of Atlantic Salmon (Salmo salar)
Authors: Shaw H. M. , Saunders R. L. , Hall H. C. , Henderson E. B.
Published: April 2011

Growth and food conversion efficiency in Atlantic salmon smolts (Salmo salar) in either fresh water or sea water were not demonstrably affected by varying the level of dietary sodium chloride. Large dietary salt loads were almost completely absorbed from the gastrointestinal tracts offish within 24 h, and plasma sodium and chloride concentrations were positively affected at this time.Irrespective of whether fish were undergoing random, spontaneous activity or an enforced, uniform low level of activity, growth rates and food conversion efficiencies were similar when fish were fed the same ration but different amounts of sodium chloride.A possible explanation is that normal renal function in fresh water provides for large amounts of hypoosmotic urine in which excess sodium chloride may be discharged without great expenditure of energy. However, in sea water, where urine flow is minimal, the main route of excretion for the excess electrolytes is across the gills, a process requiring energy.
Analysis of Open-Access Commercial Exploitation and Maximum Economic Yield in Biologically and Technologically Interdependent Fisheries
Authors: Anderson Lee G.
Published: April 2011

Fisheries may be interdependent because of biological relationships that exist between their stocks or because the gear of one affects mortality in the stock of the other. The problems of defining a maximum sustainable yield in these cases are discussed. A graphical analysis is used to describe the combinations of effort from both fisheries where concurrent exploitation is possible and which of these combinations will result in a simultaneous equilibrium. Finally the conditions for a combined maximum economic yield (MEY) are presented and it is shown that they will not hold if each fishery is managed to obtain an individual MEY.
Temperature Increase Can Cause Hyperecdysonism in American Lobsters (Homarus americanus) Injected with Ecdysterone
Authors: Aiken D. E. , Waddy S. L.
Published: April 2011

In the lobster Homarus americanus the threshold dose for premolt acceleration by ecdysterone can be altered by changes in temperature. Two dose levels of ecdysterone (0.5 and 1.0 μg/g body weight) were compared at three different temperatures (10, 17, 21 C); all three doses remained subthreshold at 10 C but at 17 C the 1.0-μg dose caused hyperecdysonism — rapid but abnormal completion of premolt terminating in death at ecdysis. In contrast, the 0.5-μg dose remained subthreshold even at 21 C. These results demonstrate a dose–temperature relation for response to injected ecdysterone.
Accumulation and Apparent Absence of DDT Metabolism by Marine Copepods, Calanus spp., in Culture
Authors: Darrow D. C. , Hakding G. C. H.
Published: April 2011

14C-p,p′-DDT was taken up from sea water by nonfeeding marine copepods held at 6 C for 8 wk. Calanus spp. reached an equilibrium DDT level of 50–100 ppm (dry weight) after 3–4 wk exposure in an initial water concentration of [Formula: see text]. No metabolites of p,p′-DDT could be detected during this period.
Some Methodology for Appraising Contaminants in Aquatic Systems
Authors: Eberhardt L. L.
Published: April 2011

Kinetic models for uptake and retention of various contaminants by aquatic biota are recommended as a useful means of summarizing and intercomparing laboratory studies, and as essential tools in analyzing field data. Some simple models are fitted to laboratory data on the uptake and retention of DDT and dieldrin by fish. The well-known relation between metabolic rate and body size is used to appraise data and concentrations of DDT, PCBs, and mercury in fish taken from lakes and oceans. Evidence suggests that uptake and retention experiments performed on small fish give very different results from those expected on individuals important in sports or commercial fisheries.
Dorsal Light Response as an Index of Prey Preference in Bluegill (Lepomis macrochirus)
Authors: Vinyard Gary L. , O’brien W. John
Published: April 2011

An apparatus utilizing the variation in the dorsal light response of sight-feeding planktivorous fish when exposed to prey of various lengths, was used to measure the predator’s interest in particular prey. Comparison of results with actual selection of prey by fish under experimental conditions confirms the importance of prey length in determining the preference of these predators.
Acute Toxicity of Benzene, a Component of Crude Oil, to Juvenile Striped Bass (Morone Saxatilis)
Authors: Meyerhoff Roger D.
Published: April 2011

As the biological effects of the volatile aromatic compounds in crude oil are not well documented a systematic examination of these compounds was initiated at the National Marine Fisheries Service at Tiburon. One of the major constituents of these aromatic compounds is benzene. The acute toxicity of benzene to 1.5 ± 0.5-g juvenile striped bass (Morone saxatilis) was studied in a continuous flow laboratory bioassay system. At 17.4 C and 29 ppt salinity, the lethal threshold concentration and the 96-h LC50 for benzene were 10.9 μl/liter. The 95% confidence interval was 10.9 ± 0.2 μl/liter and the probit line slope, "S," was 1.1.Possible toxic mechanisms are discussed.
Renal Excretion in Coho Salmon (Oncorhynchus kisutch) after Acute Exposure to 3-Trifluoromethyl-4-Nitrophenol
Authors: Hunn Joseph B. , Allen John L.
Published: April 2011

Coho salmon (Oncorhynchus kisutch) exposed to an acute, sublethal concentration of 3-trifluoromethyl-4-nitrophenol (TFM) exhibited an increased output of urine when compared with controls, but the urinary excretion of Na, K, Ca, Mg, and Cl was not affected. About 35 times more conjugated TFM than free TFM was excreted during the 24-h study period.
Improved Flowing Water Apparatus for the Culture of Brachyuran Crab Larvae
Authors: Buchanan David V. , Myers Michael J. , Caldwell Richard S.
Published: April 2011

A flowing water system is described for culture of brachyuran crab larvae. This system, which is suitable for toxicant exposure studies, employs a flow reversal principle, and a minimal area of screen placed low on the side of the culture containers. The design minimizes the problem of larval entrapment in water exit screens. Survival of Cancer magister zoeae in rearing tests lasting up to 60 days compared favorably with survivals obtained previously using static culture methods.
Physical and Chemical Characteristics of Great Bear Lake, Northwest Territories
Authors: Johnson Lionel
Published: April 2011

Great Bear Lake is geologically very young, having been derived from Glacial Lake McConnell 8,000–10,000 yr BP. The lake is made up of two basins with a total volume of 2235.7 km3. This large volume of water and the northern continental climate of the region give rise to a lake that is essentially polar (cold monomictic) although in a northern temperature setting.Chemical composition was extremely uniform; the only observable differences were local and associated with inflowing rivers. In dissolved solids content Great Bear Lake is close to the world’s average for fresh water; it is not typical of waters of the Canadian Shield. Dissolved oxygen was high at all times; it reached a maximum level under the ice in April. The deep water remained fully saturated throughout the year.Comparisons with truly arctic lakes show that Great Bear Lake is similar in many respects but in some aspects it is even more extreme. Although similar in size to Great Slave Lake, it is much more oligotrophic.
Acute Toxicity of Methyl Mercury Chloride and Mercuric Chloride for Rainbow Trout (Salmo gairdneri) Fry and Fingerlings
Authors: Wobeser G.
Published: April 2011

The median tolerance limit (MTL) for methyl mercury chloride at 24, 48, and 96 h was 0.084, 0.045, and 0.024 mg/liter as mercury, respectively, for fry; and 0.125, 0.066, and 0.042 mg/liter as mercury, respectively, for fingerlings. The MTL (24 h) for mercuric chloride for fingerlings was 0.90 mg/liter as mercury. Fingerlings exposed to methyl mercury chloride concentrated mercury in their tissues much more rapidly than did those exposed to mercuric chloride. The acute toxic action of both compounds was exerted on the gills. Mercuric chloride caused severe epithelial necrosis. Poisoning by methyl mercuric chloride was characterized by epithelial cell swelling and hyperplasia, a marked increase in the number of epithelial cells in mitosis, and terminal epithelial desquamation.
Preservation Studies of Inshore Male Capelin (Mallotus villosus) Stored in Ice
Authors: Shaw D. H. , Botta J. R.
Published: April 2011

Beach spawning male capelin (Mallotus villosus) were held in ice for up to 14 days, and the changes in chemical parameters were measured and compared with changes in taste and texture. The onset of trimethylamine production coincided with the point of rejection by sensory analysis, and hypoxanthine production was closely related to quality changes. The point of rejection of these fish at 8-days storage gave capelin a longer storage life in ice than other major pelagic species used for food, such as herring, mackerel, and sardines. Analytical values indicated that there were no changes due to development of rancidity in the fat. In general, all analyses were affected by the gross physiological differences noted in beach spawning capelin of both sexes.
Activation Energy and Allosteric Inhibition of Reaction Catalyzed by Aspartate Transcarbamylase from Atlantic Cod (Gadus morhua) Ovary
Authors: King Deborah , Baker Dwight L.
Published: April 2011

Aspartate transcarbamylase was precipitated from a 0.85% KCl extract of Atlantic cod (Gadus morhua) ovary by exhaustive dialysis. The extract contained a dialyzable, heat stable inhibitor, which when added to the reaction mixture at a concentration [Formula: see text] of that in the ovary, reduced the activity to 13% and changed the aspartate concentration vs. activity curve from hyperbolic to sigmoidal. The enzyme was also inhibited by some pyrimidine derivatives but less strongly. The activation energy of the reaction catalyzed was 13,700 cal/mol and was constant between 5 and 45 C.
Growth Rate of Young Sockeye Salmon, Oncorhynchus nerka, in Relation to Fish Size and Ration Level
Authors: Brett J. R. , Shelbourn J. E.
Published: April 2011

The specific growth rate of young sockeye salmon (Oncorhynchus nerka) was studied for a period of 7 mo to determine the effect of body weight when on restricted and unrestricted rations. It was hypothesized that a restricted ration would result in a fixed growth rate until size became a limiting factor reducing food demand below the prescribed level and thereby reducing growth rate. The results support the hypothesis, with the possible exception that growth rate may increase slightly during the period of fixed ration. On excess ration the specific growth rate fell from 3.6% weight per day (2.4 g mean weight) to 1.0% weight per day (37 g mean weight); intermediate constant growth rates accompanied the periods of fixed ration, inflecting to lower rates subsequently. The general equation log G = a + b log W (where G = specific growth rate, and W = weight in grams) was found to apply to a number of salmonids. The slope value of b = −0.4 ±.04 appears to characterize the family, with the intercept a taking on different values according to the varying capacity for rapid growth.
Excretion of Ammonia and Inorganic Phosphorus by Euphausia pacifica and Metridia pacifica at Different Concentrations of Phytoplankton
Authors: Takahashi M. , Ikeda T.
Published: April 2011

Rates of excretion in the forms of ammonia and inorganic phosphorus were determined for Euphausia pacifica and Metridia pacifica at different phytoplankton concentrations. Nutrient uptake rate of the phytoplankton sample for each experiment was determined using Michaelis-Menten kinetics. The gross excretion of nutrients by zooplankton (Eg) was estimated by summing the apparent excretion (Ea) and nutrient removed by phytoplankton (Eu) as follows:[Formula: see text]Two significant effects of phytoplankton on zooplankton excretion were recognized: 1) rapid removal from the medium of nutrients excreted by zooplankton, and 2) increase in nutrient excretion of zooplankton. Phytoplankton could remove 0–100% of the nutrients excreted by zooplankton. The increase in nutrient excretion by zooplankton due to adding phytoplankton was proportional to the amount of phytoplankton ingested. Compared with the excretion rate at zero phytoplankton density, the estimated increase in excretion rate was as high as 5 times at 15 μg chlorophyll a/liter (optimum phytoplankton density) for M. pacifica and almost 9 times at 70 μg chlorophyll a/liter for E. pacifica.
Chlorinated Hydrocarbons in Cetaceans
Authors: Taruski A. G. , Olney C. E. , Winn Howard E.
Published: April 2011

DDT, PCBs, chlordane, and dieldrin levels were measured in blubber of 18 cetaceans, including humpback, sperm, dense-beaked, Atlantic, and Pacific pilot whales, and five species of dolphins. All had significant residue levels, ranging from 1.1 to 1023 ppm ΣDDT (wet weight basis), and 0.7–147 ppm PCBs. These levels are high enough to justify efforts to reduce PCB contamination of the oceans and a continued ban on widespread use of DDT.
Biological Oceanography in Canada: A Perspective and Review
Authors: Parsons T. R.
Published: April 2011

The history of biological oceanography is reviewed with respect to developments both in Canada and other lands. From this history it is suggested that biological oceanography should be broadly defined as a study of the biology of the oceans. Narrower fields of specialization, such as planktonology, fisheries ecology, or studies on the benthic habitat, should be integrated to provide a better biological basis for understanding ocean communities.The interaction between biological oceanography and other studies in marine science is reviewed with respect to physical and chemical oceanography, fisheries, and pollution. Specific recommendations with respect to the future development of biological oceanography in Canada are made in the areas of national programs, training, instrument development, international relations, and interactions with other sciences in relation to the solution of practical problems in the marine environment.
Variability in Atlantic Cod (Gadus morhua) from the Northeast Atlantic: a Review of Seasonal and Environmental Influences on Various Attributes of the Flesh
Authors: Love R. Malcolm
Published: April 2011

Fish to be used as food are judged on the nature of the texture, flavor, odor, surface appearance, and color of the fillet. Investigations on Atlantic cod (Gadus morhua) have shown that all of these attributes can vary according to the season and the place where the fish were caught.Factors that influence one or more of the attributes are: firstly, the postmortem pH of the muscle, itself influenced by the supply of food and in some way by the body length; secondly, the lipid content, also influenced by feeding; and thirdly, the swimming activity of the fish.
Penetration of the Deep Layer of the Saguenay Fjord by Surface Waters of the St. Lawrence Estuary
Authors: Therriault Jean Claude , Lacroix Guy
Published: April 2011

A strong similarity is demonstrated in summertime physicochemical characteristics between the deep water of the Saguenay fjord and the surface water of the St. Lawrence estuary. Summer warming of the deep layer of the Saguenay is progressive from the mouth towards the head of the fjord. The mechanism proposed is the penetration of surface estuarine water over the shallow sill during the rising tide. The abnormally high chlorophyll values in this deep layer may be explained by the same advective mechanism.
Aqueous Ammonia Equilibrium Calculations: Effect of pH and Temperature
Authors: Emerson Kenneth , Russo Rosemarie C. , Lund Richard E. , Thurston Robert V.
Published: April 2011

The toxicity of ammonia to fishes has been attributed to the un-ionized ammonia chemical species present in aqueous solution. Because the percent of total ammonia present as un-ionized ammonia (NH3) is so dependent upon pH and temperature, an exact understanding of the aqueous ammonia equilibrium is important for toxicity studies. A critical evaluation of the literature data on the ammonia–water equilibrium system has been carried out. Results of calculations of values of pKa at different temperatures and of percent of NH3 in aqueous ammonia solutions of zero salinity as a function of pH and temperature are presented.
Biosynthesis of Organic Arsenic Compounds in Brown Trout (Salmo trutta)
Authors: Penrose W. R.
Published: April 2011

Radioactive, inorganic arsenic was administered to brown trout (Salmo trutta) orally and by intramuscular injection. The orally administered arsenic appeared in the tissues in an altered form that is presumed organic; this organoarsenical was also found in the gastrointestinal contents. The injected arsenic appeared in the tissues in inorganic form and was only slowly converted to organic form; meanwhile, large amounts of inorganic and organic arsenic were detected in the bile. These findings are consistent with biosynthesis of the organic arsenic compound within the gastrointestinal tract.
Reproduction, Maturation, and Identification of Larvae of some Sebastes (Scorpaenidae) Species in the Northeast Pacific Ocean
Authors: Westrheim S. J.
Published: April 2011

Insemination and parturition seasons, maturation, and descriptions of preextrusion larvae were reported for several Sebastes (Scorpaenidae) species (66,760 specimens; 31 species) studied during 1963–73 in the northeast Pacific Ocean, from Oregon (43°N) to the western Gulf of Alaska (170°W). Principal month of insemination was October. Parturition season varied considerably among species — earlier than February for two species, and later than June for five. Within species, parturition season was generally later in the higher latitudes. Maturation of both sexes included an intermediate stage whose minimum duration was 1 yr. Length–maturity relationships were determined for 18 Sebastes species. The size interval in which 50% of specimens were mature ranged from < 17 cm for male S. saxicola to 48 cm for female S. pinniger. Identification of preextrusion larvae by conventional morphological criteria was precluded by interspecific similarities and intraspecific differences. Within-area bathymetric variation in gonad development of S. alutus provided additional evidence of subpopulations.
Phytoplankton Succession and Primary Production in Babine Lake, British Columbia
Authors: Stockner John G. , Shortreed K. R. S.
Published: April 2011

Ten stations located in six zones (subbasins) were sampled biweekly from May to October 1973 to detect possible regional differences in production in this large, 155 km long, dystrophic lake. The spring bloom occurred in all zones while a fall bloom occurred only in Zones 5 and 6. Carbon assimilation showed two peaks in south basin zones, but only one (spring) at zones north of Topley Landing. Seasonal variation in phytoplankton numbers and volume, seston, and chlorophyll a followed a pattern similar to that noted for primary production. Mean production was 100 mg C∙m−2∙day−1 in Zones 1–4, but was 145 in Zones 5 and 6. Annual production was estimated at 25 g C∙m−2 in the north basin and 40 in the south basin. Reasons for the regional disparities are discussed, with greatest significance given to regional variations in mixed layer depth, surface inflows (loading), and basin mean depth. The development and sustainment of the autumnal bloom of Tabellaria fenestrata is thought to be one of the principal factors responsible for greater production in the south basin.An estimated 0.05 g TP∙m−2 enters the lake yearly. This can vary depending on the return of adult sockeye salmon (Oncorhynchus nerka), whose carcasses contribute up to 20% of the total. An estimated 30% is lost via the Babine River, and it is speculated that of the remaining 70%, most is lost to the sediments. Phosphate limitation is implied as a chief factor limiting primary production in the north basin stations, but not in the south basin. On the basis of total phosphorus load the lake is classed as oligotrophic, but in terms of annual production and its humic stained waters it is more correctly considered mixotrophic.
Possible Role of the Posterior Lateral Line in Obstacle Entrainment by Brook Trout (Salvelinus fontinalis)
Authors: Sutterlin A. M. , Waddy Susan
Published: April 2011

Observations of position holding by brook trout (Salvelinus fontinalis) in a stream channel indicate that they choose specific locations probably related to flow patterns around bottom obstructions. Bilateral denervation of the posterior lateral line system of trout has no effect on their ability to entrain on objects placed in flowing water, providing sufficient visual cues are available. Unilateral ablation resulted in a lateral bias in swimming position relative to the flow obstruction even when visual cues were present. Bilateral denervation of the posterior line system reduced the degree to which trout could entrain on objects when visual cues were omitted. It is suggested that in stream-dwelling fish, such as the brook trout, the lateral line may serve as a detector of flow or pressure discontinuities, enabling the fish to maintain position with minimum expenditure of energy.
Genetic Variation in the Pacific Oyster, Crassostrea gigas
Authors: Buroker Norman E. , Hershberger William K. , Chew Kenneth K.
Published: April 2011

Genetic variation, exhibited by electrophoretic analysis of tissue proteins and enzymes, of the Pacific oyster (Crassostrea gigas) was analyzed. Eleven systems were examined, reflecting 15 loci of which 8 were polymorphic and 7 were monomorphic. The number of alleles per locus varied from 1 at four loci (Aat-1, Mdh-1, Me, and To-1) without allelic variation, to 6 at the Pgm locus. The average number of alleles per locus was 2.7, while the effective number of alleles was calculated to be 1.3. An individual was found to be heterozygous, on the average, at 21% of the loci. Allelic variation was found at 11 out of 15, or 73% of the loci. At 53% of the loci the frequency of the most common allele was no greater than 0.95.
Relation Between Egg Size, Growth, and Natural Mortality of Larval Fish
Authors: Ware D. M.
Published: April 2011

A set of density-dependent growth and survivorship equations is derived from evidence that the instantaneous death rate in the sea is inversely proportional to particle size. The survivorship equation reproduces several well-known phenomena observed in fish populations. It predicts: 1) that winter and spring spawning species ought to produce larger eggs than summer spawners, 2) that it is advantageous for species that spawn in batches to produce progressively smaller eggs in spring and summer, and 3) that the death rate of a cohort of fish should decrease continuously as the survivors grow and approach the critical size.The biological basis for the observed variation in the size of pelagic fish eggs and larvae is thought to be due primarily to trophic relations within the pelagic community. It is suggested from what is known of the relative abundance and foraging capabilities of different sized particles, that the survival rates of larval and juvenile fish should increase as they grow and occupy a progressively higher position in the food chain.
A Small-Boat Otter Trawl for Limnological Studies
Authors: Dadswell M. J.
Published: April 2011

A small otter trawl, 2.5 m wide by 5.5 m long, is described and a method for its use by two operators from a small boat (3–5 m long) powered by an outboard motor is discussed. This small trawl proved efficient in the rapid collection of large numbers of benthic and epibenthic organisms in lakes at depths between 5 and 100 m.
Functional Hematology of Ringed Seals (Phoca hispida) in the Canadian Arctic
Authors: Geraci J. R. , Smith T. G.
Published: April 2011

Hemograms from 20 netted and 6 shot ringed seals (Phoca hispida) were studied. Changes in red and white cell values in netted seals offer evidence for functioning sympathetic and adrenal–cortical stress pathways. The very high blood oxygen carrying capacity of ringed seals suggests that the animal is capable of deep or sustained dives. A technique for blood sampling from the vertebral "extradural" vein is described.
International Joint Ventures in Fishing and 200-Mile Economic Zones
Authors: Tomlinson J. W. C. , Vertinsky I.
Published: April 2011

This paper examines the impact of various strategies that may be adopted by coastal nations for utilization of fishery resources assigned to their jurisdiction under a system of 200-mile economic zones, such as that apparently favored at the Caracas Conference on the Law of the Sea. Benefits and problems that are likely to arise out of alternative approaches are discussed in the context of experiences of developing countries with foreign investment in other sectors. The paper suggests that various forms of joint ventures appear to have the greatest chance of success in achieving both effective utilization of resources and beneficial development of the coastal nations.
The Benthos of Lakes.
Authors: Hiltunen Jarl
Published: April 2011

not available
Culture of Bivalve Molluscs: 50 years experience at Conwy.
Authors: Bernard F. R.
Published: April 2011

not available
Production by Brook Trout (Salvelinus fontinalis) in Four Streams in the Matamek Watershed, Quebec
Authors: O’Connor J. F. , Power G.
Published: April 2011

Production by brook trout (Salvelinus fontinalis) in four infertile streams on the Canadian Precambrian Shield was estimated to be between 14.5 and 66.4 kg/ha per yr during 3 successive yr of study (1971–73). These values represent the range of total fish flesh elaborated annually in these streams because trout was the only species present. Differences between streams in annual production and P: B ratios arose from variations in stream cover (and its effect on carrying capacity), recruitment, and total biomass. Variations in age-specific growth rates were not critical. Production in the two most productive streams was judged to be controlled by food, while in the other two streams lack of suitable cover for adult trout limited production.
Factors Affecting Rainbow Trout (Salmo gairdneri) Predation on Migrant Fry of Sockeye Salmon (Oncorhynchus nerka)
Authors: Ginetz R. M. , Larkin P. A.
Published: April 2011

Predation of rainbow trout (Salmo gairdneri) on migrant sockeye salmon (Oncorhynchus nerka) fry in experimental streams was higher on fry at an earlier development stage, in moonlight by contrast to cloudy night light intensities, at lesser turbidities, and at lower stream velocities. At dusk light intensities, from.05 to.30 ft-c, mortality from predation was inversely related to light intensity. The longer the period of exposure of fry to naturally declining light intensities prior to downstream movement, the lower was the loss to predators. Exposure of predators to high light intensities prior to the downstream movement of fry resulted in decreased fry mortality. Fry that had survived exposure to predators in an experimental stream 1 and 2 days previous were less vulnerable to predation than "naive" fry. Successive exposures further decreased the loss to predation. Fry enumerated at a counting fence suffered less predation than fry not enumerated. Experienced fry moved downstream more rapidly than naive fry.In laboratory aquaria, experienced fry formed compact schools prior to and in response to stimuli, while naive fry formed loose schools or did not school. Experienced fry were less active in responding to stimuli. Enumerated fry resembled experienced fry; nonenumerated fry resembled naive fry.Various techniques of enhancing sockeye salmon fry survival during downstream migration are suggested by these results.
Movement of Yellow Perch (Perca flavescens) and White Sucker (Catostomus commersoni) in a Nearshore Great Lakes Habitat Subject to a Thermal Discharge
Authors: Kelso J. R. M.
Published: April 2011

The thermal discharge from the Nanticoke Generating Station caused both yellow perch (Perca flavescens) and white sucker (Catostomus commersoni) to increase sharpness of turns, decrease distance between turns, and to orient into the current generated by the discharge. Conversely, fish released in thermally unaffected habitats referenced movement to the shoreline, turned less sharply, and swam greater distances between turns. The tendency for localization of movement was increased for both species when in the influence of the discharge. Swimming speeds were less for fish encountering the discharge; however, these fish had to contend with currents generated by the effluent thus making comparisons anomalous. Exposure of fish to elevated temperatures was brief and ranged from a few excursions into thermally elevated areas to approximately 9 h. Fish transplanted from unaffected areas to the discharge area showed behavior similar to fish caught and released at the discharge site. Two fish tracked when cooling water was discharged at ambient temperature suggested that current had a role in causing the observed changes in behavior.
Changes in Ouabain-Sensitive Adenosine Triphosphatase Activity in Gills of Coho Salmon (Oncorhynchus kisutch) During Parr–Smolt Transformation
Authors: Giles M. A. , Vanstone W. E.
Published: April 2011

The effects of incubation temperature, pH, sodium, potassium, and ATP concentration, and ouabain on the activity of Na+–K+-activated ATPase of the gills of seawater-adapted juvenile coho salmon (Oncorhynchus kisutch) were determined. The temperature and pH optima were 40 C and 7.4, respectively. The apparent Km for ATP at equimolar Mg++ concentration was 0.2 mM at Na+ and K+ concentrations of 100 and 20 mM, respectively. Maximal enzyme activity for Na+ concentration of 10.50 and 100 mM occurred at K+ concentrations of 12.5, 15.0, and 20.0 mM, respectively. The Ki for ouabain was 2 × 10−6 M and 7 × 10−6 for K+ concentrations of 10 and 20 mM, respectively.A large portion (up to 60%) of the ouabain-sensitive ATPase activity in freshwater fish was activated by sodium ions in the absence of potassium ions (Na+-activation). Exposure to sea water resulted in a large increase in total ouabain-sensitive activity and a sharp decrease in the proportion of sodium activation. These changes occurred within 14 days after transfer to full strength sea water.On a seasonal basis, total ouabain-sensitive enzyme activity in juvenile freshwater coho was low (less than 5 μmol Pi/mg N per h) to the end of November, increased to a peak (over 125 μmol Pi/mg N per h) in mid-January, and subsequently declined by late February. A slow, steady rise in activity occurred during the smoking period of March and April and the relative contribution of sodium ions to the total activity declined in this period.
Field Determination of the Critical Nutrient Concentrations for Cladophora in Streams
Authors: Wong S. L. , Clark B.
Published: April 2011

Many streams in southern Ontario experience excessive seasonal growth of aquatic plants such as Cladophora and Potamogeton. A direct relation, with a regression coefficient of 0.87, was observed between ambient P concentration in the water and P content of plant tissue in six rivers. Critical or growth controlling total P concentration of 60 μg/liter in stream water and 1.6 mg/gram dry weight in plant tissue were determined. Unlike P, no significant correlation was observed between N content of plant tissue and N concentration in water. The correlation of total P with plant growth can be used to estimate the waste load which would result in maximum growth rate of Cladophora.
Terrigenous Organic Matter in Surface Sediments from the Gulf of St. Lawrence
Authors: Pocklington Roger
Published: April 2011

Marine sediments containing land-derived organic matter can be identified by a combination of high organic carbon concentration, high C and H relative to N, and the presence of lignin. Sediments with this combination of characteristics have been found in certain environments within the Gulf of St. Lawrence, in particular, in close proximity to pulp and paper mills.
Upwelling Along the Yarmouth Shore of Nova Scotia
Authors: Garrett C. J. R. , Loucks H.
Published: April 2011

Coastal upwelling seems to occur off the southwestern shore of Nova Scotia. It is suggested that this may be driven by centrifugal forces associated with the strong tidal currents past the convex coastline, in much the same way as secondary circulation is generated for river flow round a bend.
Surface Circulation Pattern in the Gulf of St. Lawrence
Authors: El-Sabh Mohammed I.
Published: April 2011

Using all available oceanographic data in the Gulf of St. Lawrence between 1950 and 1969, a network of average stations was formed for the months of June, July, August, November, and for the winter period. The dynamic method was applied to calculate the geostrophic circulation in the Gulf during these months based on a variable reference layer.The main features of the reference layer are the steep slope along the Gaspé coast and the existence of three depressions in the Laurentian Channel, southeast and west of Anticosti Island, and in the central region of Cabot Strait. Its depth varies from 10 to 50 m in the Magdalen Shallows to more than 300 m in part of the Laurentian Channel. The general two-way flow in all entrances to the Gulf, the existence of a permanent anticlockwise gyre west of Anticosti Island, and the Gaspé and Cape Breton currents with which are associated the highest velocities in the Gulf are the main features of the circulation pattern. The circulation patterns obtained agree with the results of synoptic observations.Cyclonic and anticyclonic gyres are common in the Gulf. A comparison of the circulation patterns obtained in this study and the results of the International Biological Programme Study of the Gulf reveal that such cyclonic and anticyclonic gyres are responsible, at least in part, for the areas of maximum primary productivity west and northeast of Anticosti Island, and for the so-called "desert areas" in the northeastern side of the Gulf.
The Eosinophilic Cell of the White Sucker, Catostomus commersoni
Authors: Lester R. J. G. , Daniels B. A.
Published: April 2011

The inflammatory reaction of Catostomus commersoni to the parasites Actinobdella inequiannulata and Lernea cyprinacea, and to an experimental incision, produced tissue that contained large numbers of eosinophilic granulocytes. The cells had spherical nuclei and orange granular cytoplasm after H & E staining. In imprints of the same tissue treated with Romanowsky stains the cells had a flocculent weakly basophilic cytoplasm and sometimes contained purple granules. They were peroxidase negative. "Finely reticular cells" found in the blood had an identical appearance to the cells observed in the imprints, and were thought to be the same type of cell. They may be equivalent to mammalian eosinophils.
Adaptive Control of Fishing Systems
Authors: Walters Carl J. , Hilborn Ray
Published: April 2011

This paper discusses some formal techniques for deciding how harvesting policies should be modified in the face of uncertainty. Parameter estimation and dynamic optimization methods are combined for the Ricker stock-recruitment model to show how exploitation rates should be manipulated to give more information about the model parameters; in general, harvesting rates should be lower than would be predicted by the best fitting recruitment curve unless this curve predicts that the stock is very productive. A decision procedure is developed for comparing alternative stock-recruitment models; when applied to the Fraser River sockeye salmon (Oncorhynchus nerka), the procedure indicates that an experimental increase in escapements would be quite worthwhile. It appears that there is considerable promise for extending these methods and procedures to cases where the stock size is unknown and where fishing effort is poorly controlled.
Purging a Muddy–Earthy Flavor Taint from Rainbow Trout (Salmo gairdneri) by Transferring to Artificial and Natural Holding Environments
Authors: Iredale D. G. , York R. K.
Published: April 2011

Studies were conducted to determine the length of time required to purge a muddy–earthy flavor taint from pond cultured rainbow trout (Salmo gairdneri) transferred to two different clear water environments. Sensory data from trained judges show that this required 5 days for fish transferred to a rapidly changing purified artificial water environment and 16 days for fish transferred to a relatively static natural water environment to reduce this taint to or below threshold levels of recognition.
Quantifying Nutrient Requirements of Fish
Authors: Zeitoun Ibrahim H. , Ullrey Duane E. , Magee William T. , Gill John L. , Bergen Werner G.
Published: April 2011

Four replicates of 50 rainbow trout (Salmo gairdneri) fingerlings each were assigned to each of seven dietary protein levels from 30 to 60% in 5% increments. Percentage weight gains for 10 wk were related to dietary protein levels using an analysis of variance and multiple comparisons of the means, a "broken line" analysis, and a polynomial regression analysis. When correctly used, one of these techniques should lead to a reasonable conclusion concerning dietary protein requirements. However, the polynomial regression analysis has the advantage of being continuous, like the relation of growth to dose, and should be more accurate than the other methods when the intervals between experimental dietary nutrient concentrations are wide. The polynomial regression analysis also provides the basis for making economic decisions relative to protein requirements for maximum economic returns.
Blood Lactate Levels in Free-Swimming Rainbow Trout (Salmo gairdneri) Before and After Strenuous Exercise Resulting in Fatigue
Authors: Driedzic William R. , Kiceniuk Joe W.
Published: April 2011

Rainbow trout (Salmo gairdneri) were exercised to fatigue in a series of 60-min stepwise increasing velocity increments. There was no increase in blood lactate concentration, serially sampled during swimming by means of indwelling dorsal and ventral aortic catheters, at velocities as high as 93% of critical velocity of individuals. The data show that under these conditions the rate of production of lactate by white muscle, at less than critical velocities, is minimal or that the rate of elimination of lactate from white muscle is equal to its rate of utilization elsewhere. Immediately following fatigue blood lactate level increases rapidly. During the recovery period there appears to be a net uptake of lactate by the gills.