bluuebunny/crossref_metadata_2025 huggingface dataset:
Diel Periodicity of Chlorophyll a Concentration in Oregon Coastal Waters
Authors: Glooschenko Walter A. , Curl Jr. Herbert , Small Lawrence F.
Published: April 2011

Concentrations of chlorophyll a in phytoplankton exhibited a diel periodicity in Oregon coastal waters. Maximum surface concentrations often occurred around midnight and highest 25-m concentrations early in the evening (or even in late afternoon). Concentrations at intermediate depths fell in between and in a predictable progression with depth and time of day. Minimum chlorophyll a values occurred in the afternoon. No definite periodicity was established at 50 m.Laboratory studies with Skeletonema costatum demonstrated that the diel cycle of chlorophyll a per cell was related to the light intensity and duration to which cells were exposed. Highest concentrations of this pigment occurred early in the dark period and lowest concentrations in the light period when cells were grown under photoperiods of 9, 12, and 15 hr at a light intensity of approximately 1200 ft-c. Pigment bleaching probably was responsible for the low concentrations during the light period. The decline of chlorophyll a from the maximum early in the dark period began after the cells possibly became deficient in some chlorophyll precursor or energy-yielding substrate. Addition of an external carbon source during the dark period prolonged the high chlorophyll a concentrations in the dark before the decline began. Under low light (400 ft-c) chlorophyll a synthesis occurred only in the light. This phenomenon was most likely due to an insufficient amount of energy-yielding substrate or precursor synthesized during the low-light period, and the lack of bleaching in the light period at this lower intensity. The laboratory results were consistent with interpretations of the field data. A correction for diel pigment periodicity is recommended for models estimating photosynthesis from chlorophyll and light data and for oceanographic surveys during which sampling of chlorophyll a is carried out throughout the 24-hr day.
An Application of Louver Deflectors for Guiding Atlantic Salmon (Salmo salar) Smolts From Power Turbines
Authors: Ducharme L. J. A.
Published: April 2011

Louver deflectors for guiding Atlantic salmon (Salmo salar) away from destructive power turbines were installed in a canal leading to the powerhouse at East River, Sheet Harbour, Nova Scotia, in 1966. Guiding efficiency studies, using hatchery-reared smolts, showed that a minimum approach:bypass velocity ratio of 1.0:1.5 was a prerequisite to high guiding efficiency. From 1967 to 1971, average guiding efficiency was increased from 57% to 80% through modifications which increased velocity and reduced flow turbulence in the bypass. A significant correlation existed between approach velocity and guiding efficiency within the range tested after bypass hydraulics had been modified. Tests conducted with varying louver bar spacing ranging from 5.1 to 30.5 cm (2–12 inches) showed that the wider spacings did not impair guiding efficiency.Vertical distribution of smolt migrants in the power canal indicated that over 80% of the fish remained above depth 1.3 m. This was borne out by the fact that the bypass was effective when operating to a depth of only 0.91 m. An appraisal of the practicality of the louver guiding system is presented.
Effects of Controlled Flow Reduction on a Trout Stream
Authors: Kraft Melvin E.
Published: April 2011

The total number of brook trout age I and older in three runs of Blacktail Creek, Mont., was reduced approximately 62% when 90% of the normal flow was diverted for about 3 months, in comparison with 20% for runs in control sections. Both number and weight of trout in pools of the test sections generally increased, whereas those in control pools decreased. Recaptures of tagged trout also indicated movements from runs to pools in the test sections, but not in the control sections. When the flow was reduced 75% or less, there were no consistent changes in number or weight of trout in the test runs and pools, whereas those in the control sections were more marked though also inconsistent. Reduced flows had no consistent effect on the number of underyearlings. The changes in most physical characteristics after 90% flow reduction were considerably less than the degree of reduction, presumably because the stream flowed in a well defined channel. Surface area and average depth were least affected (about 42% decrease) and current velocity (75%) the most. Fast-water portions (current velocity over 0.30 m/sec) comprised over 60% of the surface area at normal flows and slow water portions over 85% of the area when the flow was reduced 90%. A multiple linear regression with the physical characteristics as independent variables and the number of trout as the dependent variable accounted for over 75% of the variation in the number of age I and older trout in runs and pools.
Respiratory Adaptations of Prenatal Young in the Ovary of two Species of Viviparous Seaperch, Rhacochilus vacca and Embiotoca lateralis
Authors: Webb P. W. , Brett J. R.
Published: April 2011

The structure of the ovary and embryos of embiotocids is reviewed in relation to those factors that would affect the exchange of materials between ovarian and embryonic blood streams. Weight, exchange surface areas (particularly of the fins), diffusion distances, and capillary densities were measured for prenatal young and ovaries of two species of Embiotocidae, Rhacochilus vacca and Embiotoca lateralis, during middle and late gestation. Brood size and ovarian fluid volume were also measured. Changes in brood weight and ovarian fluid volumes were interpreted in relation to the load imposed on the ovary by the young. This was expressed as the brood/ovary weight ratio which was found to increase during gestation to a maximum value of eight. Changes in exchange surface areas and diffusion distances of the young and the ovary were determined and evaluated in relation to the metabolic requirements of the brood. Convection of the ovarian fluid must occur as a necessary mechanism for efficient exchange of materials with increasing brood/ovary weight ratio. It is further concluded that the supply of materials to the brood would be limited by ovarian blood-flow characteristics rather than structural considerations, except immediately prior to parturition.
Distribution and Morphological Variation of Lampsilis radiata (Pelecypoda, Unionidae) in Some Central Canadian Lakes: A Multivariate Statistical Approach
Authors: Green Roger H.
Published: April 2011

Discriminant analysis performed on 62 samples containing Anodonta grandis and 52 samples containing Lampsilis radiata collected from 19 lakes in central Canada indicated separation in terms of an environmental factor which was interpreted as suitability of water chemistry for construction of shell. A canonical correlation analysis on morphological and environmental variables for 70 specimens of L. radiata yielded two highly significant canonical variates which related components of environmental variation to components of morphological variation. One was interpreted as variation in water turbulence, which primarily affected overall size. The other was similar to the factor which separated A. grandis from L. radiata and was interpreted similarly. Shell weight, or thickness, rather than overall size, was affected. Environments were successfully predicted for shells from two locations not included in the original analysis.
Eggs and Larvae of Northern Sand Lance (Ammodytes dubius) from the Scotian Shelf
Authors: Scott J. S.
Published: April 2011

Eggs from stomachs of yellowtail flounder (Limanda ferruginea) from Emerald Bank, south of Nova Scotia, were identified as those of northern sand lance, Ammodytes dubius. They were larger than those of other Ammodytes species, with a mean diameter of 1.05 mm. Ovarian eggs from ripe A. dubius were smaller (mean diameter 0.7 mm) with a unimodal distribution of egg diameters, indicating a single spawning each season.Larvae were widespread and abundant on the Scotian Shelf from February to April. They hatched at about 4-mm length and grew to about 25-mm length between February and May on Emerald Bank. Growth rates decreased to the north. Numbers and distribution of melanophores changed with larval length, but showed no differences in number at given length between geographical areas. Change in numbers of anal, caudal, and dorsal fin rays followed a pattern similar to that of corresponding melanophores.
Mercury Concentration in Relation to Size in Several Species of Freshwater Fishes from Manitoba and Northwestern Ontario
Authors: Scott D. P. , Armstrong F. A. J.
Published: April 2011

Statistical analysis of 53 samples of 11 species of fishes from a number of areas of Manitoba and northwestern Ontario indicated that in general there was a positive correlation between mercury concentration and length. There also appeared to be a more variable positive relation between mercury concentration and fish condition (fatness). It was possible to predict, for 31 of the 53 samples, the range of lengths within which there was a 95% probability of all fish containing less than 0.5 ppm mercury. However, within species the relation between mercury concentration and length was not consistent. The results show that, for certain of the populations closed to commercial fishing because of mercury contamination, selection (by fishing technique or otherwise) of certain sizes should provide fish of acceptably low mercury concentration.
Effects of Various Metals on Survival, Growth, Reproduction, and Metabolism of Daphnia magna
Authors: Biesinger Kenneth E. , Christensen Glenn M.
Published: April 2011

The toxicities of various metals to Daphnia magna were evaluated on the basis of a 48-hr 50% lethal concentration (LC50) a 3-week LC50, and a 16% decrease in the number of young born (reproductive impairment). The 3-week 16% reproductive impairment concentrations (in micrograms per liter) for the metal ions tested were: Na(I), 680,000; Ca(II), 116,000; Mg(II), 82,000; K(I), 53,000; Sr(II), 42,000; Ba(II), 5800; Fe(III), 4380; Mn(II), 4100; As(V), 520; Sn(II), 350; Cr(III), 330; Al(III), 320; Zn(II), 70; Au(III), 60; Ni(II), 30; Pb(II), 30; Cu(II), 22; Pt(IV), 14; Co(II), 10; Hg(II), 3.4; and Cd(II), 0.17. At metal concentrations permitting survival but impairing reproduction, daphnids weighed less than control animals. Amounts of total protein and glutamic oxalacetic transaminase activity varied with the different metals. The negative logarithm of the solubility product constant (pKsp) of the metal sulfides, electronegativity, and the logarithm of the equilibrium constant (log Keg) of the metal–ATP complex were positively correlated with toxicity to D. magna. Other physicochemical properties were considered, but no additional correlations were found.
Growth, Life History, and Respiration of Mysis relicta in an Arctic and Temperate Lake
Authors: Lasenby D. C. , Langford R. R.
Published: April 2011

Mysis relicta from Char Lake (N.W.T.) take 2 years to reach maturity, retaining 36 cal as net production; those from Stony Lake (southern Ontario) mature in 1 year, retaining 53 cal as net production. Growth rates were highest during summer months for individuals in both lakes. Results of respiration experiments at 0, 2, 4, 6, and 8 C for Char Lake mysids and at 2, 4, 7, 10, and 13 C for Stony Lake mysids were not significantly different, indicating that Mysis relicta demonstrates no metabolic compensation over its environmental temperature range. Generalized energy budgets were constructed for individuals from each population for their entire life-span. A female uses approximately 209 cal for growth and respiration to become a reproducing adult in one year in Stony Lake and approximately 206 cal to become a reproducing adult in 2 years in Char Lake.
Use of a Commercial Dredge to Estimate a Hardshell Clam Population by Stratified Random Sampling
Authors: Russell Jr. Howard J.
Published: April 2011

With stratified random sampling, use of a commercial dredge provided a valid estimate of the population of the hardshell clam Mercenaria mercenaria in Narragansett Bay, Rhode Island. Because of the nonrandom distribution pattern of M. mercenaria, treatment of the data with normal statistics would indicate a mean of 1.64 bu per dredge tow with a variance of 1.80. Stratified sampling, due to its inherent weighting feature, provided a similar estimate of 1.36 bu per tow with a variance of 0.033.
Summer Storage of Energy and Its Use for Winter Metabolism and Gonad Maturation in American Plaice (Hippoglossoides platessoides)
Authors: MacKinnon J. C.
Published: April 2011

American plaice (Hippoglossoides platessoides) in St. Margaret's Bay, Nova Scotia, had an annual energy storage cycle in which a mature 35 cm female stored 92 kcal during the summer period and used this energy for metabolism (72 kcal) and gonad maturation (20 kcal) in winter months. An additional 21 kcal was stored in the ovary during the summer period. These energy changes occurred in a fish with a total energy content of approximately 300 kcal and an annual energy increment of 51 kcal due to growth in length. The annual energy variation in immature females and males was less than in mature females. A comparison of summer production (143 kcal, excluding gonad energy) with net annual production (51 kcal) for a 35 cm female plaice indicated that higher yields would be obtained by harvesting at the end of the summer period than by taking the same fish at the end of the overwintering period.
Size Selection of Daphnia pulicaria by Yellow Perch (Perca flavescens) Fry in West Blue Lake, Manitoba
Authors: Wong Brian , Ward F. J.
Published: April 2011

Prior to mid-July, Daphnia pulicaria in yellow perch (Perca flavescens) fry stomachs were smaller than those in plankton collections but after this date mean lengths of D. pulicaria in stomachs and collections were similar indicating an initial selection for small D. pulicaria by the fish. The relation between D. pulicaria body depth and perch mouth gape width indicated that perch fry less than 18 mm long, a length attained in mid-July, could not readily ingest D. pulicaria with body depths greater than 0.7 mm (1.3 mm long). The heterogenic relation between growth in mouth and body size enabled perch fry in West Blue Lake to quickly utilize, as an energy source, the abundant D. pulicaria population.
An Instrument for Measuring Conductivity Profiles in Inlets
Authors: Farmer D. M. , Osborn T. R.
Published: April 2011

An instrument is described for obtaining profiles of seawater conductivity in the upper few meters of estuarine waters. The system is self-contained and runs for one week between chart replacements; it is housed in a buoy which can be moored to a log-boom or floating dock. Contours of constant conductivity derived from the chart records have provided a graphic description of wind effects in Alberni Inlet.
Feeding, Growth, and Productivity of Northwest Atlantic Harp Seals (Pagophilus groenlandicus)
Authors: Sergeant D. E.
Published: April 2011

The food of harp seals inhabiting the northwest Atlantic consists chiefly of pelagic fish, especially capelin, Mallotus villosus, and pelagic and benthic Crustacea (Euphausiacea, Mysidacea, Amphipoda, Decapoda), with smaller quantities of benthic fish. Feeding has been observed to take place on individual items by suction, and small fish are taken tail first. Feeding is intensive in winter and (by deduction) in summer, less intensive during spring and autumn migration, and in spring during whelping and moult. A weight loss in spring due chiefly to loss in thickness of subcutaneous fat (blubber) is most intensive in adult females as a result of lactation. This loss is made up slowly in summer. The preparturient females are partly segregated in midwinter on what may be the best feeding grounds. During lactation, and immediately following it when they are again segregated from other age-sex groups, adult females tend to feed on decapod Crustacea. In spring, the only time when all age classes are in the same geographic area, there is a stratification of feeding by size of organism and by depth, from chiefly Euphausiacea taken in surface waters by the weaned young, through capelin taken probably at intermediate depths by the immature animals, to herring, cod, and other groundfish taken by the moulting adults to depths of perhaps 150–200 m. Social feeding begins at about 1 year of age with the change from Crustacea to pelagic fish. From knowledge of the rate of feeding, body weights, and reproductive rates, the ecological efficiency of harp seals (i.e. weight of annual increment of population/weight of annual food eaten) is calculated at 0.005, a low figure. Annual weights of food items eaten by the northwest Atlantic population of harp seals are roughly estimated as: all organisms, 2 × 106 metric tons; capelin, 0.5 × 106 tons; and herring, 2 × 104 tons. Predation by harp seals on capelin stocks off eastern Canada occurs only during the winter months when pack ice is present as a resting substrate, the same resource being consumed in the summer months by the great whales (Balaenopteridae).
Balanced Versus Geostrophic Wind-Stress for Hudson Bay
Authors: Murty T. S. , Yuen K. B.
Published: April 2011

Wind-stresses for Hudson Bay for May and September were computed by the geostrophic relation and the balance equation, making use of data averaged over 30 years. The balanced wind-stress for either strong (September) or weak (May) pressure gradient situations was found to be substantially different from the corresponding geostrophic stress. The wind-generated circulations in the water in Hudson Bay calculated using the balanced and the geostrophic wind-stress showed significant differences, the former agreeing better with the observed average circulation.
Thiobarbituric Acid Value, Total Long-Chain Free Fatty Acids, and Flavor of Pacific Halibut (Hippoglossus stenolepis) and Chinook Salmon (Oncorhynchus tshawytscha) Frozen at Sea
Authors: Botta J. R. , Richards J. F. , Tomlinson N.
Published: April 2011

The effects of brine-freezing and plate-freezing at sea upon 2-thiobarbituric acid (TBA) values, concentration of long-chain free fatty acids (FFA), and flavor of Pacific halibut and chinook salmon were determined at intervals during subsequent storage of the glazed, polyethylene covered fish at − 30 C. Evaluations were conducted on both outside and inside muscle.Brine-frozen samples of outside muscle generally had higher TBA values than plate-frozen samples and the differences were most pronounced at intermediate storage times (26–45 weeks).Method of freezing significantly (P ≤ 0.05) affected the concentration of total FFA in Pacific halibut, and the total FFA concentration of both Pacific halibut and chinook salmon significantly increased with length of frozen storage. For both species the concentration of total FFA was significantly greater in outside than in inside muscle.Significant flavor differences between brine- and plate-frozen samples of outside muscle were evident at intermediate storage times for both species. For inside muscle of halibut, the significance of flavor differences generally increased with storage time whereas flavor differences for inside muscle of salmon were consistently nonsignificant.Taste panel results and TBA values indicated that, in comparison to plate-freezing, brine-freezing impaired the quality of outside muscle of Pacific halibut and chinook salmon during the early stages of frozen storage.
Gill Irrigation and Pressure Relationships in Rainbow Trout (Salmo gairdneri)
Authors: Davis John C. , Randall David J.
Published: April 2011

In studies on 11 rainbow trout (Salmo gairdneri), 217.3 ± 6.5 g, 14.0 ± 0.5 C) fitted with rubber membranes for direct measurement of ventilatory water flow [Formula: see text], buccal, cleithral, and differential pressure traces increased in amptitude as [Formula: see text] rose from 40 to 160 ml/min. Ventilation rate remained steady at around 77 breaths/min in the [Formula: see text] range 40–120 ml/min and rose to 90 breaths/min at a [Formula: see text] of 175 ml/min. Oxygen uptake more than doubled as [Formula: see text] rose from 40 to 120 ml/min. Calculated utilization of oxygen from the inspired water declined only slightly over this [Formula: see text] range, indicating that large increases in nonrespiratory spillage of water (anatomical dead space) had not occurred. The calculated oxygen cost of breathing was low. Area mean differential pressure appeared closely related to [Formula: see text] over the [Formula: see text] range 40–160 ml/min. Area mean differential pressure increased from two- to four fold over this [Formula: see text] range, depending upon which individual fish was examined. Over the [Formula: see text] range 40–160 ml/min the calculated resistance of the gill sieve did not appear to decline although some variability was present and a variety of gill sieve resistances could be measured at a given [Formula: see text] for each fish. It is concluded that changes in [Formula: see text] are largely dependent on changes in mean differential pressures across the gills, with no marked decline in gill sieve resistance over the normal physiological range of [Formula: see text].
Evidence for Homing in the Mosshead Sculpin (Clinocottus globiceps)
Authors: Green John M.
Published: April 2011

Observations on 86 tagged mosshead sculpins (Clinocottus globiceps) show that this species exhibits fidelity to specific tide pools and returns to them when displaced to other tide pools.
Mesopelagic Fishes from the Gulf of Maine and the Adjacent Continental Slope
Authors: Musick John A.
Published: April 2011

Otter-trawl records and midwater-trawl catches suggested that some mesopelagic fishes are permanent members of the midwater fauna of the Gulf of Maine rather than strays. Benthosema glaciale, Ceratoscopelus maderensis, Myctophum punctatum, and Maurolicus muelleri, cold water or ubiquitous species, occur in the Gulf throughout the year, and warmwater species derived from adjacent Slope Water offshore were captured in the Gulf during the summer and fall. Nine species of mesopelagic fishes are here recorded from the Gulf for the first time.
Growth and Cell-Size Distribution of Marine Planktonic Algae in Batch and Dialysis Cultures
Authors: Prakash A. , Skoglund Liv , Rystad Britt , Jensen Arne
Published: April 2011

An extended exponential growth phase and a higher maximum population characterized growth of planktonic algae in a dialysis system compared with that in a batch system. Algal cells grown in a dialysis culture had higher chlorophyll content and a larger average cell size than those grown in a batch culture. In both types of culture, changes in cell-size distribution were related to the phases of the growth cycle with maximum cell-size during the stationary phase. Various interactions of the component reactions of photosynthesis leading to changes in growth pattern and cell-size distribution are discussed.
Effect of Season on Salt-Extractable Protein in Muscle from Trawler-Caught Cod and on its Stability During Frozen Storage
Authors: Castell C. H. , Bishop Doris M.
Published: April 2011

Periodical tests made on 272 fillets from fresh, postrigor, trawler-caught cod have shown that there is a slight decrease in salt-extractable proteins during the spring spawning period (March, April, and May). This was accompanied by a similar slight decrease in the lipid content of the muscle.When other fillets from these same lots of cod were frozen and stored at − 3.3 C and − 12 C, those from the fish caught during the spring spawning period tended to deteriorate faster, as indicated by the rate at which the EPN values decreased during storage. When the fish were stored at − 26 C for up to 2 years, the EPN changes during storage were so retarded that seasonal differences in storage quality could not be observed.
Survival and Gill Condition of Bluegill (Lepomis macrochirus) and Fathead Minnows (Pimephales promelas) Exposed to Sodium Nitrilotriacetate (NTA) for 28 Days
Authors: Macek Kenneth J. , Sturm Robert N.
Published: April 2011

Acute dynamic bioassays with fathead minnows and rainbow trout indicated that the 96-hr median tolerance limits of sodium nitrilotriacetate (NTA) exceed 1000 times the mean environmental levels that might be anticipated from detergent use. A 28-day dynamic bioassay with bluegill and fathead minnows indicated a lack of cumulative toxicity associated with levels of NTA up to 1000 times expected environmental concentrations in water. Fishes exposed to 96 mg/liter NTA for 28 days exhibited no NTA-induced gill pathology.
A Cyprinodontid Fish, Jordanella floridae, as a Laboratory Animal for Rapid Chronic Bioassays
Authors: Smith Wesley E.
Published: April 2011

The flagfish (Jordanella floridae) is proposed as a useful laboratory fish for chronic toxicity studies. It matures rapidly, reaching breeding age in 6–8 weeks under optimum conditions, and the fish will spawn at any time of the year. The adults are sexually dichromatic. A complete chronic test may be conducted with this species in as little as 3–4 months.
Copper Induced Lesions in Estuarine Teleosts
Authors: Gardner George R. , LaRoche Gilles
Published: April 2011

Cellular changes attributable to copper were observed in the mechanoreceptors of the lateral line canals in the head of adult mummichog (Fundulus heteroclitus) and Atlantic silverside (Menidia menidid). The epithelium of these canals was also altered in F. heteroclitus. In both species, lesions were observed in the olfactory organs, which included the chemoreceptive sites. These manifestations of copper poisoning were evident at all studied concentrations (0.5, 1.0, and 5.0 mg/liter) of the metal. In M. menidia dilation of blood vessels was apparent, and in five cases hemorrhage had occurred in the brain and in periorbital connective tissues.Renal lesions in F. heteroclitus exposed to 1.0 and 5.0 mg/liter of copper were apparent; these changes could not be identified in M. menidia. Hepatic changes were not detectable by light microscopy in either species following external exposures to copper. High concentrations of copper administered intraperitoneally to F. heteroclitus did induce liver damage.Fry of F. heteroclitus were more sensitive to copper than were the adults or their zygotes. The emergence of larval forms from the zygote, the time required for emergence, and their survival was impaired by the metal. Lesions were not evident in developing sensory areas of the lateral line or the olfactory systems in these immature forms.
Metabolic Rates and Critical Swimming Speeds of Sockeye Salmon (Oncorhynchus nerka) in Relation to Size and Temperature
Authors: Brett J. R. , Glass N. R.
Published: April 2011

Ten years research on metabolic rates and swimming speeds of sockeye salmon (Oncorhynchus nerka) ranging in weight from 2 to 2000 g, at temperatures from 2 to 24 C, is reviewed and summarized. Analysis of weight–slope relations (b values) at three temperatures, using log–log transformations, provided an overall mean of 0.88 for standard metabolism and 0.99 for active metabolism. A previously determined semilog equation for temperature effect on standard metabolic rate (at approximately 50 g) was supported by supplementary data at 2 C. Predictive graphic models in the form of isopleths of metabolic rates and critical swimming speeds in relation to weight, length, and temperature are depicted. These provide a composite presentation useful in estimating the metabolic rate and maximum sustained speed for any size and temperature.
Changes in Hematocrit and Hemoglobin in Atlantic Salmon (Salmo salar) as a Result of Furunculosis Disease
Authors: Foda A.
Published: April 2011

Decreases in the hematocrit and hemoglobin levels in hatchery-reared juvenile Atlantic salmon (Salmo salar) were associated with a severe infection of Aeromonas salmonicida, the causative agent of furunculosis disease. The lowering of blood hematocrit and hemoglobin levels were attributable to hemorrhages resulting from the infection.
Temperature Effects on Mercury Accumulation, Toxicity, and Metabolic Rate in Rainbow Trout (Salmo gairdneri)
Authors: MacLeod J. C. , Pessah E.
Published: April 2011

Mercury toxicity in rainbow trout fingerlings was related to temperature and chemical formulation of the mercury. At 10 C, the 24-hr TLm concentration (median tolerance limit) for mercuric chloride (HgCl2) was approximately 30 times that for phenyl mercuric acetate (PMA). The 96-hr TLm values for mercuric chloride at 5, 10, and 20 C were 0.40, 0.28, and 0.22 mg Hg/liter. The velocity of mortality, (V = reciprocal of time to death in hours), was linearly related to temperature. For a mercuric chloride concentration of 0.5 mg Hg/liter, V =.002 +.0023t, where t = temperature in centigrade degrees.Temperature also affected accumulation rate of mercury in the fish muscle. At 5, 10, and 20 C a mercuric chloride concentration of 0.1 mg Hg/liter in the water produced biological magnification factors (conc. in fish ÷ conc. in water) of 4, 10, and 22 ×, respectively, PMA produced higher magnification factors of 80–100 × at 10 C.Active metabolic rate, though increased by higher temperatures, was depressed by mercuric chloride, and higher temperatures augmented the depressant effect.
Influence of Lead and other Metals on Fish δ-Aminolevulinate Dehydrase Activity
Authors: Jackim Eugene
Published: April 2011

Exposing mummichog (Fundulus heteroclitus) and winter flounder (Pseudopleuronectes americanus) to sublethal concentrations of lead resulted in reduction of liver and kidney δ-aminolevulinic acid dehydrase activity. The results of this project are expected to afford an index of response to heavy metals in estuarine waters.
Effects of Temperature on Mortality of Fingerling Channel Catfish (Ictalurus punctatus) Experimentally Infected with Channel Catfish Virus
Authors: Plumb John A.
Published: April 2011

When water temperature was reduced from 28 to 19 C for channel catfish (Ictalurus punctatus) fingerlings 24 hr after injection with channel catfish virus (CCV), 24% mortality occurred. In comparison, fish held at a constant temperature of 28 C had a mortality of 94% and those held in 19 C water had 14% mortality. Reducing the temperature to 19 C when the first deaths occurred at 28 C (64–72 hr after injection) resulted in 78% mortality. Insignificant mortality occurred in fish injected with Hanks’ balanced salt solution. Results of temperature change are discussed as to their potential value in reducing the effects of CCV disease under cultural conditions.
Evidence of Interspecific Interactions in the Respiration of Tubificid Oligochaetes
Authors: Chua K. E. , Brinkhurst R. O.
Published: April 2011

Determination of respiration of Tubifex tubifex, Limnodrilus hoffmeisteri, and Peloscolex multisetosus in the laboratory provided evidence of interspecific interactions between two tubificid species. The same individuals in mixed species culture respire significantly less than in pure culture. The effector of the interaction in the one interaction between T. tubifex and L. hoffmeisteri is waterborne, smaller than 0.45 μ, and it is rendered ineffective by heating at 60 C for 20 min.
Behavior of Young Atlantic Salmon (Salmo salar) Exposed to or Force-Fed Fenitrothion, an Organophosphate Insecticide
Authors: Symons P. E. K.
Published: April 2011

Exposure of young Atlantic salmon (Salmo salar) to 1.0 ppm fenitrothion for 15–16 hr caused a 50% decrease in the number holding territories 6 days following treatment. Some severely affected fish also swam stiffly and ceased feeding, but these effects disappeared within 48 hr following return to clean water. Territories were not reclaimed for approximately 2–3 weeks. Exposure to 0.1 ppm fenitrothion for 15–16 hr caused a lesser (20%) reduction in numbers of fish holding territories.When mealworms (Tenebrio sp.) injected with 2–5-μliters pure (100%) fenitrothion were force-fed to young salmon, 50% were regurgitated 8–12 hr afterwards. Almost all mealworms containing 10–20-μliter fenitrothion were regurgitated. The proportion of worms regurgitated remained constant during a week of daily force-feedings but, 24 hr after the third or fourth feeding, all fish except controls could be made to flex tetanically by rapping on the aquarium, and they made little attempt to escape a dipnet.
Some Short-term Indicators of Sublethal Effects of Copper on Brook Trout, Salvelinus fontinalis
Authors: Drummond R. A. , Spoor W. A. , Olson G. F.
Published: April 2011

Changes in cough frequency, locomotor activity, and feeding behavior of yearling brook trout appeared within 2–24 hr at copper concentrations as low as 6–15 μg/liter. Each of these responses appears to be useful for predicting the concentration range of copper likely to have no long-term effects on the species.
Effects of Cooking on Concentrations of PCB and DDT Compounds in Chinook (Oncorhynchus tshawytscha) and Coho (O. kisutch) Salmon from Lake Michigan
Authors: Smith Waldina E. , Funk Kaye , Zabik Mary E.
Published: April 2011

Concentrations of polychlorinated biphenyls (PCBs) and DDT compounds in chinook (Oncorhynchus tshawytscha) and coho (O. kisutch) salmon steaks were reduced slightly by cooking. In chinook, poaching and baking caused reductions of PCBs and pesticides of 2–8% while baking in nylon cooking bags reduced residue levels 11–16%. No significant differences in residue levels were found between chinook steaks cooked with and without skin, while steaks from the anterior halves contained less PCB and pesticide on a fat basis than steaks from the posterior halves. Analyses of a limited number of coho steaks indicated that they were lower in PCB and DDT compounds than the chinook steaks but showed no consistent pattern of reduction due to cooking method.
Respiration of Arctic Char (Salvelinus alpinus) From a High Arctic Lake
Authors: Holeton G. F.
Published: April 2011

The routine of resting oxygen consumption of Arctic char (Salvelinus alpinus) from a high arctic lake (74°42′N) was measured at 2 (acclimated) and 6 C (unacclimated). The oxygen uptake versus wet weight relation at 2 C was: Log O2 uptake = 0.7316 Log weight – 1.0944. Oxygen uptake was low, not showing any evidence of "cold adaptation," and was comparable to projections of oxygen uptake versus temperature relations of other salmonid fish from lower latitudes.The short term metabolic response to a rise in temperature of 4 C was independent of body size except with fish with yolk sacs and weighing less than 0.125 g.
Molybdenum Concentrations in Tissues of Rainbow Trout (Salmo gairdneri) and Kokanee Salmon (Oncorhynchus nerka) from Waters Differing Widely in Molybdenum Content
Authors: Ward James V.
Published: April 2011

Concentrations of molybdenum in tissues of rainbow trout (Salmo gairdneri) from three waters increased only slightly with increase in molybdenum concentration of the water. Fish from high (300 ppb) molybdenum water had mean concentrations of 13–332 ppb on a wet-weight basis; those from low (6 ppb) molybdenum water, 10–146 ppb; and those from trace molybdenum water, 5–118 ppb. Rainbow trout exhibited generally higher molybdenum concentrations than did kokanee salmon (Oncorhynchus nerka) in high molybdenum water. A possible plateau mechanism concerning molybdenum accumulation by salmonids is discussed.
Cadmium Uptake by Fiddler Crabs Exposed to Temperature and Salinity Stress
Authors: O’Hara James
Published: April 2011

Adult fiddler crabs, Uca pugilator, exposed to various temperature and salinity regimes and 10 ppm Cd++ accumulated maximum cadmium in conditions of high temperature and low salinity.
Effects of Reduced Oxygen Concentrations on Northern Pike (Esox lucius) Embryos and Larvae
Authors: Siefert Richard E. , Spoor William A. , Syrett Roll F.
Published: April 2011

At 15 and 19 C, and at flows of 60 and 30 ml/min (velocities about 3.3 and 1.6 cm/min), 50% oxygen saturation was sufficient for survival and development of northern pike (Esox lucius) from fertilization until all surviving larvae fed. Oxygen tensions of about 33% saturation appeared inadequate for proper survival.
Role of Woody Debris in Nest Site Selection by Pumpkinseed Sunfish, Lepomis gibbosus
Authors: Colgan Patrick , Ealey David
Published: April 2011

Nesting preference for areas cleared of woody debris over areas cluttered with such debris was indicated by more nesting in cleared areas at the beginning and end of the breeding season, and more spawning activity in cleared areas. During heavy nesting, however, no preference was observed due to the density-dependent constraint of a high breeding population limiting available nesting space. This lack of difference in nesting densities at peak times indicates that breeding density cannot be enhanced in pumpkinseed sunfish by the creation of additional environmental boundaries. Nest density was influenced by the type of substrate of the site. In cluttered sections, nest diameters and distances to nearest cover were less than, and nearest neighbor distances not significantly different from, those in cleared sections.
Correlations between Seasonal River Discharge and Local Landings of American Lobster (Homarus americanus) and Atlantic Halibut (Hippoglossus hippoglossus) in the Gulf of St. Lawrence
Authors: Sutcliffe Jr. W. H.
Published: April 2011

Positive correlations are found between monthly discharge of the St. Lawrence River and annual regional catch of American lobster (Homarus americanus) and Atlantic halibut (Hippoglossus hippoglossus). Lag periods to account for age at maturity or commercial size permit some predictive possibilities.
Food of American Plaice (Hippoglossoides platessoides) from the Grand Bank, Newfoundland
Authors: Pitt T. K.
Published: April 2011

Invertebrates, principally benthic forms, occurred most frequently in plaice stomachs from the Grand Bank. Fish, almost entirely capelin and sand lance, however, contributed the greatest proportion of total weight: 85% on the southeast part of the bank (ICNAF Division 3N) and 55% in the northeast section (ICNAF Division 3L).A seasonal feeding cycle was difficult to document because of the lack of winter samples, however, a greater proportion of empty stomachs occurred in February and March. The greater average weight of contents in spring samples (April–June) in Division 3L and in fall samples (October–November) for Division 3N was probably related to the availability of capelin and lance. The greater annual consumption of capelin and lance in Division 3N apparently accounted for the estimated higher caloric values of the average contents in this division than in Division 3L.
Coastal Movements of Mature Fraser River Pink Salmon (Oncorhynchus gorbuscha) as Revealed by Ultrasonic Tracking
Authors: Stasko A. B. , Horrall R. M. , Hasler A. D. , Stasko D.
Published: April 2011

Eleven mature pink salmon (Oncorhynchus gorbuscha) were tracked in September 1967 for periods of 3–50 hr over distances from 2 to 127 km to determine migration patterns.The fish were classified as "active" or "passive." Active fish moved faster and their paths were straighter. Active tracks ended distant from and to the north (toward the Fraser River) of the release point; passive tracks ended near or south of the release point. Active fish did not follow shorelines, but travelled primarily along the axes of tidal currents. They moved both with the northward flood and against the southward ebb currents, during day and at night. Average ground speed of active fish was 62 cm/sec (2.2 km/hr).
Oxygen Consumption of Adult Petromyzon marinus in Relation to Body Weight and Temperature
Authors: Beamish F. W. H.
Published: April 2011

The logarithm of standard oxygen consumption of adult Petromyzon marinus increased linearly with the logarithm of weight at each of 5, 10, and 15 C. The proportionate change in standard oxygen consumption for a given change in temperature was independent of size, the mean regression coefficient being 0.949. Standard oxygen consumption for a sea lamprey of fixed weight increased from 52.7 to 124.0 mg/kg per hr over the range 5–20 C with the greatest changes occurring between 10–15 C, 64.5–114.3 mg/kg per hr. Active oxygen consumption was estimated for a few individuals at 10 C and found to be 475.5 mg/kg per hr, within the range reported for teleosts.
Pressure-Sensing Ultrasonic Transmitter for Tracking Aquatic Animals
Authors: Luke D. McG. , Pincock D. G. , Stasko A. B.
Published: April 2011

A small transmitter (7 × 1.6 cm) for telemetering swimming depth of aquatic animals was developed. The transmitter operates for 3 days with a signal range of about 1 km in sea water. It codes depth to 40 m or more as changes in pulse repetition rates, detectable by standard ultrasonic receivers.
Gas-Exchange Rates in a Small Lake as Determined by the Radon Method
Authors: Emerson Steve , Broecker Wallace , Schindler D. W.
Published: April 2011

The radon method, used previously in ocean-atmosphere systems, is used here to determine the gas-exchange rate between the atmosphere and lake 227 of the Experimental Lakes Area. Fertilization of the lake with nitrogen and phosphorus caused the carbon dioxide partial pressure in the lake water to drop well below atmospheric levels; hence, in order to better understand the carbon budget of the lake, an estimate of the CO2 gas-exchange rate was necessary.To determine gas-exchange rates by measuring radon evasion to the atmosphere the source of radon in the lake water must be dissolved radium. Since the radon concentration in lakes derives not only from the decay of dissolved radium but also from the inflow of radon-rich groundwaters, radium was added to the lake to increase the radon concentration well above this fluctuating background level. Although this procedure was complicated by algal uptake of the radium in the lake (Emerson and Hesslein 1973), we were able to place limits on the gas-exchange rate.Our results indicate that the "stagnant boundary layer" thickness is approximately 300 μ. This value is among the largest observed in natural waters. Using this value and the partial pressure of CO2 in the lake water we have calculated an invasion rate of 17 ± 8 mmoles CO2/m2 day.
Vertical Eddy Diffusion Studies in the Thermocline of a Small Stratified Lake
Authors: Hesslein R. , Quay P.
Published: April 2011

Values for K, the coefficient of vertical eddy diffusion in the thermocline of lake 227, a small, highly stratified, and artificially eutrophied lake in northwestern Ontario, Canada, are presented. Three methods: the classical temperature method of McEwen, a dye method, and a new method using a RAGAPOS (Radon Gas Point Source), were used. Results ranged from 2 × 10−4 cm2/sec by the Rn method to 34 ×10−4 cm2/sec by temperature method; the dye method resulted in an average value of 12 × 10−4 cm2/sec. The recycling of ΣCO2 resulting from particulate degradation below the epilimnion was calculated. The results ranged from 8 to 53% of the net loss of carbon from the empilinion depending on the K value used. Results from the radon method are considered to be more accurate than results from the temperature method.
Movements of Phosphorus Between its Biologically Important Forms in Lake Water
Authors: Lean D. R. S.
Published: April 2011

A model consistent with the kinetics of phosphorus in epilimnetic lake water was developed. Adding 32PO4 to lake water and separating the major forms of dissolved phosphorus by Sephadex gel filtration showed that the exchange mechanism between inorganic phosphate and the particulate fraction predominates. At the same time, a low-molecular-weight phosphorus compound is excreted which combines with colloids in lake water, releasing phosphate from the colloid and making the phosphate available for "transfer" again. This rapid cycling of phosphorus between the four principal forms — the particulate fraction, the low-molecular-weight P compound, colloidal P, and phosphate — appears to contribute to formation of colloids in lake water. No direct complexing of phosphate to the colloid was observed. Only in the presence of algae, bacteria, and other particulate matter did the radioactive phosphorus move to the low-molecular weight and the colloidal forms. The low-molecular-weight compound is negatively charged, as is the colloidal P, but to a lesser degree. Both are removed by anion exchange materials along with phosphate, but the rate that they move into the fraction removed by membrane filtration is different from that for phosphate. When filtrate is refiltered a large amount of the colloidal P is retained by the filter. This complicates measurements of transfer and makes previous studies on utilization of dissolved organic phosphorus of doubtful value since corrections for filter retention were rarely, if ever, made.
Heterotrophic Utilization of Sucrose in an Artificially Enriched Lake
Authors: Thompson B. M. , Hamilton R. D.
Published: April 2011

Utilization of sucrose by heterotrophic microorganisms was measured in a small lake enriched with 5.54 g C/m2 per year as sucrose. Heterotrophic activity exhibited fluctuations representing the damped oscillations of a disturbed steady state system, stabilizing 3 months after the commencement of enrichment. By late summer, reduction of the weekly addition of sucrose to a few micrograms per liter was accomplished within a day by the increased microbial activity resulting from rapid growth of heterotrophic microorganisms. Heterotrophic conversion (preenrichment) of sucrose to particulate carbon in the epilimnion between July and October 1971 was 2–17% of primary production. 25–35% of total sucrose utilized was converted to carbon dioxide, the remainder being incorporated into particulate material or released as nonvolatile products of metabolism.
Bioassay Procedures to Evaluate Acute Toxicity of Neutralized Bleached Kraft Pulp Mill Effluent to Pacific Salmon
Authors: Davis John C. , Mason Barbara J.
Published: April 2011

A series of bioassays was carried out to assess the acute toxicity of neutralized, filtered, bleached kraft pulp mill effluent (BKME) from a single mill to underyearling Pacific salmon in fresh soft water, at 10–13 C. Toxicity expressed in terms of the 96-hr LC50 varied from 22% of full strength BKME to nontoxic in different collections. A procedure is described for estimating the 4-day LC50 from geometric mean survival time data. Toxicity of effluents changed unpredictably with storage (even at 2 C), and declined with air stripping. Comparison of continuous flow and static test procedures indicated that continuous flow procedures yield somewhat higher toxicity results than static tests. Experiments with varying fish densities indicate that measurable toxicity is less in static tests with heavy fish loading. Use of loading densities of 2.5 liters/g fish or better is recommended. Young sockeye salmon (Oncorhynchus nerka) appeared most sensitive, and pink (O. gorbuscha) and coho (O. kisutch) salmon somewhat more resistant to toxic BKME solutions. No correlation was found between time to death and condition factor in the size range of underyearling coho tested (3.0–7.3 cm). Recommendations are made for routine and regulatory bioassay procedures.
Postglacial Colonization of the Matamek River, Quebec, by Fishes
Authors: Power G. , Pope G. F. , Coad B. W.
Published: April 2011

Since all species of fish in the Matamek River and tributaries are euryhaline and since the number of species present at any location decreases progressively from the mouth to the headwaters, recolonization must have proceeded only from the Gulf of St. Lawrence. The distribution of species in the system, especially the locations of isolated and relict populations, indicates the order in which these species arrived in the system.
Vocalization in the Ringed Seal (Phoca hispida)
Authors: Stirling Ian
Published: April 2011

The ringed seal (Phoca hispida), previously thought to be silent, was found to emit vocalizations under water that were not readily audible to man through the ice. The four vocalizations identified (high- and low-pitched barks, yelps, and chirps) probably facilitate communication and social organization.