bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxygen Consumption of Embryos and Parents, and Oxygen Transfer Characteristics Within the Ovary of Two Species of Viviparous Seaperch, Rhacochilus vacca and Embiotoca lateralis
Authors: Webb P. W. , Brett J. R.
Published: April 2011

Oxygen tension and content of intraovarian fluid were measured for the viviparous pile perch, Rhacochilus vacca, during middle and late gestation. Oxygen tension decreased with increasing demands of the brood, reaching a minimum of 13.7 mm Hg just prior to parturition. Total oxygen content of the ovarian fluid decreased to a minimum of 22 mg O2, rising thereafter to 54 mg O2 at parturition as the volume of ovarian fluid increased. The in vitro oxygen consumption of the young per unit weight increased 2.5 times during gestation reaching 222 mg O2/kg/hr at birth (mean weight 3.8 g).Oxygen consumption of two pregnant striped seaperch, Embiotoca lateralis, was fairly constant at 70 mg O2/kg/hr early in gestation, increasing later to approximately 107 mg O2/kg/hr at parturition.An oxygen dissociation curve was determined for ventricular blood of pregnant pile perch. The p50 was 12.5 mm Hg. Along with other parameters, this was used to estimate the oxygen transfer characteristics of the brood–ovary exchange system, maximum possible oxygen consumption, and ovarian blood flow rate. The capacity of the system to meet the increasing requirements of the young decreased during gestation, reaching limiting conditions at parturition. It was concluded that transfer of oxygen to the young would be controlled by, and ultimately limited by, ovarian blood flow rate. The brood–ovary system is compared with the mammalian placenta.
Some Effects of Artificial Fertilization on Enclosed Plankton Populations in Marion Lake, British Columbia
Authors: Dickman Mike , Efford Ian E.
Published: April 2011

After single applications of nutrients to enclosures in Marion Lake in each of three seasons (fall, summer, and spring), primary productivity always increased within a 2-week period whether nitrate, phosphate, or a combination of the two was used. The species that responded to the three nutrients generally differed both within and between seasons. In all seasons, there was a decrease in total plankton diversity (based on productivity) accompanied by an increase in relative productivity of a few phytoplankton species. During fall, phosphate (P) was most stimulatory, raising primary productivity 6 mg C/m3 per hr above that of the unenriched control. During spring, N + P was most stimulatory (23 mg C/m3 per hr) and nitrate (N) next (11 mg C/m3 per hr). In summer, N + P was again most stimulatory (44 mg C/m3 per hr), primary production in the untreated lake rarely exceeding 4 mg C/m3 per hr. Of the species that increased in density, 78% were not detectable (< 1 cell/ml) at the time of fertilization. A rapid increase in density of rare species culminated in an algal bloom 2–3 weeks after fertilization.After the first phase of succession following fertilization, there was an increase in plankton diversity. At 1.5 months after fertilization, the diversity and the number of species detected were as high as or higher than before fertilization. In addition, the number of phytoplankton species per liter did not decrease significantly after enrichment though diversity decreased sharply due to the increase in abundance of a few species.
Comments on the Nomenclature of Some Subgenera of Salmonidae
Authors: Vladykov V. D. , Gruchy C. G.
Published: April 2011

Nomenclatural problems in some subgenera of Salmonidae are cleared away with the diagnoses of three new subgenera, viz: Parahucho Vladykov, Parasalmo Vladykov, and Rhabdofario Cope.
Device for Measuring Length and Girth of Fish
Authors: Hunter Charles J. , Wheeler Chester O.
Published: April 2011

Continued improvement in fish-measuring devices is necessary in fishery science. A length and girth measuring device was developed that will make multiple measurements rapidly on live fish with accuracies to 1 mm. Construction plans are available.
The Representation of Lower Molecular Weight Fatty Acids by the Bligh and Dyer Extraction Method
Authors: Hurst R. E.
Published: April 2011

The Bligh and Dyer method of lipid extraction was investigated to determine the distribution of low molecular weight free fatty acids in the organic phase. Two solvent systems were studied: one using chloroform, methanol, and distilled water; the other using an aqueous fish extract containing natural buffer in place of distilled water. The low molecular weight fatty acids were not well represented in the chloroform layer and the presence of a buffer further depressed their distribution into the organic phase. Proportionately with increased molecular weight a greater percent of acid was recovered in the chloroform. Essentially total partitioning into the organic phase in both systems occurred at a carbon chain length of ten (decanoic acid).
Flesh Concentration of Various Long-Chain Free Fatty Acids 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

Changes in the concentration of long-chain free fatty acids were determined gas chromatographically from inside and outside muscle samples of brine- or plate-frozen Pacific halibut and chinook salmon stored for 9–81 weeks.With both species the concentration of individual free fatty acids was greater in outside muscle than in inside muscle. Few differences in concentration of free fatty acids were noted between plate- and brine-frozen samples. Numerous free fatty acids increased significantly in concentration during frozen storage. For both species the increase was most rapid during the first 26–45 weeks of storage. The detection of flavor differences was unrelated to the concentration of individual free fatty acids.
Winter Surface Currents Around Cape Breton Island
Authors: Ingram R. Grant
Published: April 2011

The winter surface circulation around Cape Breton Island was studied by tracking ice fields. The resulting streamlines compare favorably with prior work.
Transatlantic Migration of a Harp Seal, Pagophilus groenlandicus
Authors: Sergeant D. E.
Published: April 2011

A harp seal, Pagophilus groenlandicus, tagged in the Gulf of St. Lawrence, was recovered at sea off northern Norway at 14 months of age. From tag recoveries, the degree of transfer eastward of young animals from the morphologically most distinct western population of harp seals can be assessed at about 1%, and from the central to the morphologically rather similar eastern population, about 10%.
A Genetic Analysis of Hatching Time in Steelhead Trout (Salmo gairdneri)
Authors: McIntyre J. D. , Blanc J.-M.
Published: April 2011

The elapsed time from fertilization through hatching for steelhead trout (Salmo gairdneri) was obtained from groups of eggs that were fertilized according to a factorial breeding plan in which 24 males were each mated to each of 10 females. Data were obtained from the eggs of 240 crosses held in an incubator through hatching and from replicated crosses held in an incubator for most of the incubation period, then in troughs. Estimated heritabilities for hatching time were 0 and 0.23, respectively, for these data, the differences being of additive genetic origin. Because of a significant genotype–environment interaction, it was suggested that hatching may have been controlled by different genetic mechanisms in the two environments.
Reproduction of the Bloodworm (Glycera dibranchiata) in the Sheepscot Estuary, Maine
Authors: Creaser Jr. Edwin P.
Published: April 2011

The population of bloodworms (Glycera dibranchiata) at Wiscasset, Maine, is composed of five assumed year-classes. Most spawners are probably large 3- and 4-year-old bloodworms. At Wiscasset eggs are released into the coelom at a size of 21 μ. The rate of egg growth varies with season. In June 1–10 million eggs are spawned at a diameter of 151–160 μ. A bottom temperature in excess of 13 C seems necessary for spawning to occur. Spawning occurs in the afternoon, between 2 hr before and 1 hr after high water. Males emit streams of sperm while swimming at the surface; females swim rapidly at the surface and suddenly rupture, liberating all the eggs at once. Females are slightly more abundant than males in the flats. Spawning bloodworms are preyed upon by herring gulls (Larus argentatus) and striped bass (Morone saxatilus), while spent epitokes are consumed by the mud shrimp (Crangon septemspinosus), which in turn is eaten by striped bass.
Swimming Performance of Young Atlantic Salmon (Salmo salar) as Affected by Reduced Ambient Oxygen Concentration
Authors: Kutty M. N. , Saunders R. L.
Published: April 2011

As oxygen concentration is lowered, a point is reached, the critical oxygen level, at which juvenile Atlantic salmon (Salmo salar) stop swimming in a tunnel respirometer. At concentrations just above the critical level, salmon frequently lose position in the upstream end of the respirometer and fall back to the downstream end while still headed into the current. There appears to be a progressive decrease in locomotor activity, indicated by reduced tailbeat frequency, on approaching the critical concentration. Swimming performance of Atlantic salmon is more highly dependent on oxygen concentration than is that of rainbow trout (Salmo gairdneri), goldfish (Carassius auratus), or Tilapia. The critical oxygen level for salmon swimming at 55 cm/sec is about 4.5 mg/liter, in comparison with 2.0 for rainbow trout, 1.7 for goldfish, and 1.0 for Tilapia. Between the minimum speed at which a salmon swims steadily and the maximum of which the fish is capable, the critical oxygen level rises with increase in swimming speed. Stoppage of swimming at the critical level is not owing to fatigue; fish resume swimming within minutes of the oxygen level being raised only slightly. The high critical oxygen levels for salmon in relation to other species including rainbow trout, another salmonid, point up the need for maintenance of stringent water quality criteria for oxygen levels in salmon rivers.
Sublethal Effects of Bleached Kraft Pulp Mill Effluent on Respiration and Circulation in Sockeye Salmon (Oncorhynchus nerka)
Authors: Davis John C.
Published: April 2011

Sublethal effects of aerated neutralized, filtered, full bleach kraft mill effluent (BKME) on circulation and respiration of Pacific salmon were examined. Ventilatory water flow, oxygen uptake, cough frequency, and buccal pressure increased in a group of 19 sockeye salmon, Oncorhynchus nerka, 207–321 g, at 10.5 ± 0.5 C, upon initial exposure to sublethal BKME concentrations. The threshold concentration for these responses appreared to be around 20% of the 4 day LC50 (static bioassay).Following overnight exposure to BKME, ventilatory volume, oxygen uptake rate, cough frequency, and oxygen utilization tended to approach pre-exposure levels, particularly at the higher sublethal contractions. Changing effluent toxicity, acclimation phenomena, or physiological adjustment are discussed as possible explanations for these results.Measures of arterial oxygen tension in sockeye salmon indicated that arterial tension declines rapidly and remains depressed following up to 24 hr exposure to BKME (33–47% of 4 day LC50). On the average this decline represented a 20% decrease in oxygen saturation of the blood. Decreased arterial PO2 may be due to mucous production at the gills and resulting gas diffusion problems, as well as abnormalities in ventilation. Reduction in scope for activity might result from impaired oxygen uptake at the gills. A similar response was observed in rainbow trout, Salmo gairdneri.
A New Species of Marine Triclad Turbellarian of the Genus Sabussowia from Prince Edward Island
Authors: Ball Ian R.
Published: April 2011

A new species of marine triclad turbellarian, Sabussowia wilhelmii sp. nov., is described from the Pisquid River, Prince Edward Island, Canada. This represents the first occurrence of the genus and of the subfamily Cercyrinae of the Procerodidae in North America. The genus is discussed and a key to the known species is provided. A detailed discussion of the status of Vortex warreni of Girard and Procerodes warreni of Wilhelmi is given. The identity of the former cannot be ascertained. The latter could be a Sabussowia species, but, in the absence of fully mature material, this question cannot be resolved. Both names are regarded as nomina dubia, and the suppression of the genus Fovia of Girard is recommended.
Linear Regressions in Fishery Research
Authors: Ricker W. E.
Published: April 2011

A number of regression situations in fish and fishery biology are examined, in which both of the variates are subject to error of measurement, or inherent variability, or both. For most of these situations a functional regression line is more suitable than the ordinary predictive regressions that have usually been employed, so that many estimates now in use are in some degree biased. Examples are (1) estimation of the exponent in the weight:length relationship, where almost all published values are somewhat too small; and (2) estimating the regression of logarithm of metabolic rate on log body weight of fish, where the best average figure proves to be 0.85 rather than 0.80. In the very common situation where the distribution of the variates is non-normal and open-ended, a functional regression is the most appropriate one even for purposes of prediction. Two ways of estimating the functional regression are (1) from arithmetic means of segments of the distribution, when computed symmetrically; and (2) from the geometric mean of one predictive regression and the reciprocal of the other. The GM regression gives a more accurate estimate when it is applicable; it is appropriate in all situations where the variability is mainly inherent in the material (little of it due to errors of measurement), or where the measurement variances are approximately proportional to the total variance of each variate; and it is the best estimate available for short series with moderate or large variability even when neither of these conditions applies. When error in X results solely from the measuring process the predictive regression of Y on X is also the functional regression if observations of X are not taken at random but rather have pre-established values, as is usual in experimental work. The uses of the various regressions are summarized in Table 8.
Influence of Temperature on Energy Utilization of Embryonic and Prolarval Tautog, Tautoga onitis
Authors: Laurence Geoffrey C.
Published: April 2011

When daily energy budgets were calculated by two methods for tautog, Tautoga onitis, from fertilization to complete yolk absorption at three temperatures (16, 19, and 22 C), neither method indicated a deficiency of yolk energy for growth and metabolism prior to exogenous feeding capability. Deficits were indicated on the day of feeding capability at all temperatures by the oxygen consumption method, the more precise but less inclusive of the two. The dry weight method, which gave the more conservative estimates, indicated no deficit for the entire period of yolk absorption at 16 C, a deficit one day after feeding capability at 19 C, and a deficit on the day of feeding capability at 22 C.Regression analysis of oxygen consumption indicated that 22 C may be in the upper temperature limits for normal metabolism by embryonic and prolarval tautog. Yolk utilization efficiencies and postlarval size at complete yolk absorption tended to be inversely related to temperature. The ecological implications and the effects of temperature on the critical timing involved in the interactions of feeding capability, availability of prey and occurrence of energy deficits are discussed.
Food and Inferred Feeding Behavior of Northern Sand Lance (Ammodytes dubius)
Authors: Scott J. S.
Published: April 2011

Gut contents of northern sand lance (Ammodytes dubius) were identified, measured by volume, and compared to volumetric analyses of plankton hauls. A. dubius is a plankton feeder, copepods (mainly Calanus finmarchicus) constituting about 65% of its food by volume. It combines filter feeding with selective feeding on larger food items such as euphausiids and fish larvae.
Mercury, DDT, and PCB in Harbour Seals (Phoca vitulina) from the Bay of Fundy and Gulf of Maine
Authors: Gaskin D. E. , Frank R. , Holdrinet M. , Ishida K. , Walton C. J. , Smith M.
Published: April 2011

Samples of blubber, longissimus muscle, liver, and cerebrum from 12 harbour seals (Phoca vitulina) were analyzed for DDT, dieldrin, PCBs, and total mercury content. The results were compared with those obtained previously for harbour porpoises (Phocoena phocoena). DDT and PCB levels appear to be of the same magnitude in the fat of seals from both southern New Brunswick and southern Maine, being lowest in a lactating female. Virtually no o,p′-DDT and relatively little dieldrin were found in seal fat, in contrast to porpoises, which contained significant amounts of both in the depot fat. Mercury levels were generally similar to those found for porpoises, but total liver Hg was considerably greater in adults from the New Brunswick islands than in those from the southern Maine ledges.
Macrobenthic Ecology of a Sawdust-Bearing Substrate in the Penobscot River Estuary (Maine)
Authors: Shorey Wayne K.
Published: April 2011

The macrobenthos of sawdust-bearing substrates in the Penobscot River estuary (Maine) were sampled bimonthly from January through November 1968. The polychaete Scolecolepides viridis and the bivalves Macoma balthica and Mya arenaria dominated the sandy sediments of the shallow station. Prionospio malmgreni and Corophium volutator were dominant in the granular substrate of the deeper station. The population of the shallow station (1-m depth, mean low water) was seasonally more stable and had a higher mean monthly bio-index (number of individuals/number of species) than that of the deeper station (6-m depth, mean low water).
Spontaneous Nephroblastoma in a Rainbow Trout (Salmo gairdneri)
Authors: Odense P. H. , Logan V. H. , Baker S. R.
Published: April 2011

A neoplasm in a rainbow trout (Salmo gairdneri) identified as a nephroblastoma is described and its possible pathological implications discussed. The characteristic conditions of abortive renal tubules and glomeruli in a fibrous stroma were observed; however, metastases were absent. The simultaneous presence of inflammatory kidney disease made association of clinical signs with the neoplasm impossible. This is the first case of nephroblastoma in Canadian hatchery stock. The etiological factors are unknown.
Optimal Control Theory Applied to a Dynamic Aquatic Ecosystem
Authors: Ahmed N. U. , Georganas N. D.
Published: April 2011

In this report we present a dynamic model for an aquatic ecosystem consisting of a single species living in a polluted environment. Considering the dynamics of growth of the species and increase in pollution, we apply optimal control theory to obtain species removal and pollution reduction rates at minimum cost.
Determination of Age and Growth of Populations of the White Sucker (Catostomus commersoni) Exhibiting a Wide Range in Size at Maturity
Authors: Beamish Richard J.
Published: April 2011

The use of the scale method to determine age of mature white suckers should be avoided. Sections of pectoral fin rays can provide accurate age determinations for most populations once the position of the first annulus has been identified. The age of immature white suckers can be estimated by both methods. It is suggested that, for identification of the first fin ray annulus and facility in the determination of the age of immature white suckers, both pectoral fins and scales should be sampled in all age and growth studies of this species.White suckers (Catostomus commersoni) from populations examined in this study attained ages of up to 17 years although little or no growth occurred in the latter years. Considerable variation in size at sexual maturity was found throughout the range for this species and, thus, the validity of a subspecies designation for a dwarf white sucker (C. c. utawana) based primarily on size differences should be reexamined.
Taxonomy and Ecology of Three New Species of Monodiamesa Kieffer, with Keys to Nearctic and Palaearctic Species of the Genus (Diptera: Chironomidae)
Authors: Sæther Ole A.
Published: April 2011

Three Nearctic species of Monodiamesa are described: Monodiamesa depectinata sp.n. from male imagines, pupa, and fourth- and third-instar larvae; Monodiamesa tuberculata sp.n. from imagines, pupae, and fourth- and third-instar larvae; and Monodiamesa prolilobata sp.n. from male imagines. A larva possibly belonging to M. prolilobata is described. These are the first records and descriptions of imagines of Nearctic species of this genus.Keys are given for male imagines, pupae, and larvae of the Nearctic and Palaearctic species of the genus.Monodiamesa depectinata occurs in the Laurentian Great Lakes area and in Lake Winnipeg, Man. It was taken from sandy substrates in the lower littoral and the sublittoral zones of oligotrophic to mesotrophic lakes. Monodiamesa tuberculata occurs from the mainland of British Columbia through the prairie provinces and the Northwest Territories to the Laurentian Great Lakes. It was taken from the sublittoral and profundal zones of oligotrophic lakes and in some lakes is probably a glacial relict. Monodiamesa prolilobata, from west of the Rocky Mountains, probably covers the combined ecological niches of the two more easterly species.
First Records of the Stoneroller (Campostoma anomalum) and the Blackstripe Topminnow (Fundulus notatus) from Canada
Authors: Gruchy C. G. , Bowen R. H. , Gruchy I. M.
Published: April 2011

Stoneroller (Campostoma anomalum) and blackstripe topminnow (Fundulus notatus) were found, respectively, in the Thames and Sydenham rivers of southwestern Ontario. These are new records for Canada.
Electrophoresis of Fish Myofibrillar Proteins With Sodium-Dodecyl Sulfate-Polyacrylamide Gel
Authors: Childs E. A.
Published: April 2011

A method for electrophoretic separation of fish myofibrillar proteins is described. After incubation in phosphate buffer containing β-mercaptoethanol, sodium-dodecyl sulfate (SDS), and urea, the proteins are separated by SDS-acrylamide gel electrophoresis.
Chemical Communication among Lobsters (Homarus americanus)
Authors: McLeese D. W.
Published: April 2011

Lobster’s feeding response to cod and lobster muscle extracts is temporarily eliminated by satiation with flounder. Satiated lobsters respond to water from tanks containing other lobsters except that from intermolt females. Dilute urine from molted lobsters is stimulatory to satiated males; otherwise, urines cause little or no response. The responses by satiated animals are presumed to be social. Rather than a sex specific response only, there appears to be a general chemical communication among lobsters, mediated by a pheromone or pheromones.
Some Physiological Aspects of Sublethal Heat Stress in the Juvenile Steelhead Trout (Salmo gairdneri) and Coho Salmon (Oncorhynchus kisutch)
Authors: Wedemeyer Gary
Published: April 2011

A rapid (3 min) but sublethal temperature increase from 10 to 20 imposed a greater stress on juvenile coho salmon (Oncorhynchus kisutch) than on juvenile steelhead trout (Salmo gairdneri). Both species suffered hyperglycemia, hypocholesterolemia, increased blood hemoglobin, and decreased blood sugar regulatory precision, but the steelhead recovered more quickly. Acid–base equilibrium was essentially unaffected, and only the coho suffered any significant interrenal vitamin C depletion. Vitamin C normalization required about 24 hr.
Mercury in Seals from Eastern Canada
Authors: Sergeant D. E. , Armstrong F. A. J.
Published: April 2011

Mercury concentrations in the tissues of four species of seals from individual localities in eastern Canada were highest in liver (usually 1–100 ppm) but up to 387 ppm and lowest in blubber (usually 0.1 ppm). Levels in muscle ranged from < 0.16 to 2.35 ppm. Values similar to those in muscle were found in the few specimens of heart, intestine, and lungs analyzed, and higher values in kidney and hair. Ratios of mercury in the liver to that in the muscle for adult seals were much greater than those found in two species of freshwater fish and three species of domestic animals exposed to wide ranges of mercury concentrations in their food. The ratios for seal pups, however, resembled those in the other animals.Mercury in seals increased with age and appeared to vary with the position in the marine food web of the organisms which they eat. Harp seals (Pagophilus groenlandicus), which feed on small pelagic fish and crustaceans, accumulated an order of magnitude less mercury than grey (Halichoerus grypus) and harbour (Phoca vitulina) seals, which live on large pelagic and benthic fish and cephalopods. However, grey and harbour seals are resident in eastern Canadian waters, which presumably contain higher mercury levels than arctic waters, where harp seals spend about half the year. Yet hood seals (Cystophora cristata), which spent more than half the year in arctic waters but feed on large fish and cephalopods, had mercury levels as high as grey and harbour seals.
Some Behavioral Interactions of Spottail Shiners (Notropis hudsonius), Yellow Perch (Perca flavescens), and Northern Pike (Esox lucius)
Authors: Nursall J. R.
Published: April 2011

Dense schools of spottail shiners (Notropis hudsonius) are common in shallow water in Beaver Lake, generally 0.25–0.30 m below the surface, with smaller individuals more numerous towards the top. Position in the shcool is maintained by short radius behavior. The course of an individual is maintained by a beat of the tail, a glide, a hesitation, and a change of direction. Each glide path represents the chord of an arc of short radius about some neighbor. Shiners respond to disturbance by flash expansion of loose cruising association. Schooling is obligatory. The black caudal spot is probaly multifunctional as a recognition mark and releaser.Yellow perch (Perca flavescens) show an ontogeny of behavior through young-of-the-year, aggregation-sized perch (aggp), subadults, and adults. They behave as individuals or associate as streams. Disturbance will cause a group of aggp to disperse or to stream. The adult manifestation of streaming is pack-hunting. The activity of one perch attracts the attention of others; this leads to streaming or pack-hunting. Pack-hunting improves the chance of some members of the pack, not necessarily the initiator, capturing active prey, by countering the allaesthetic protean escape reactions of organisms such as the spottail shiner. Large mixed aggregations of spottail shiners and aggp are fortuitous.Northern pike (Esox lucius) are lone, opportunistic predators whose hunting technique combines in sequence motionlessness, axial tracking, and lunging. Prey may be swallowed head- or tailfirst, or sideways.The species studied here show a range of gregariousness, from the solitary pike, through the facultative nonpolarized and polarized schools of perch, to obligate nonpolarized and polarized schools of shiners.
Growth Rates of Intertidal Molluscs as Indicators of Effects of Unexpected Incidents of Pollution
Authors: Black Robert
Published: April 2011

Shells of living molluscs contain a record of previous growth rate if the time interval between check marks is known. The check marks in Mytilus edulis and Littorina littorea are probably annual marks. Growth rates of Mytilus in 1969, the year of significant elemental phosphorus pollution at Long Harbour, Newfoundland, were no different from those in preceding or succeeding years. No Littorina alive in 1969 occurred at Long Harbour, but they were abundant at other locations. This sort of analysis, used with caution because effects of pollutants may be confounded with effects of other variables, provides a method of examining nonlethal effects of unexpected polluting events.
A Syringe Gas-Stripping Procedure for Gas-Chromatographic Determination of Dissolved Inorganic and Organic Carbon in Fresh Water and Carbonates in Sediments
Authors: Stainton Michael P.
Published: April 2011

A simple, rapid method for determining dissolved inorganic carbon in water is described. A 20-cm3 sample of water is drawn into a 50-cm3 polypropylene syringe and acidified by injection of 1 cm3 of dilute sulphuric acid. Twenty-nine cubic centimeters of helium at atmospheric pressure is injected into the syringe followed by 10 sec of manual agitation to partition CO2 between gas and liquid phase. The gas phase containing 60% of CO2 from the sample is then analyzed by gas chromatography. This method has been used to determine dissolved inorganic and organic carbon in Canadian Shield waters and to determine total carbonates in sediments.
Mercury Uptake and Ion Distribution in Gills of Rainbow Trout (Salmo gairdneri): Tissue Scans with an Electron Microprobe
Authors: Olson Kenneth R. , Fromm Paul O.
Published: April 2011

Mercury was found in gills of rainbow trout (Salmo gairdneri) which had been exposed to inorganic mercury but not in those exposed to methyl mercury. No specific site for mercury uptake was identified and it is suggested that inorganic mercury enters the gill across the general lamellar surface. High concentrations were found associated with the gill cartilage. Since little ion diffusion occurs during tissue preparation, localization and/or identification of tissues can be accomplished by scans for various elements: sodium (Na), potassium (K), chlorine (Cl), and sulfur (S). The technique is not suitable for identification of highly volatile compounds such as methyl mercury due to the necessity of subjecting tissues to high vacuum conditions, however, we believe electron probe analyses should be useful in studies of active ion transport systems in gill tissue and in investigations of the effects of heavy metal pollutants on fishes.
Identification of Fungal Encrustation on the Shell of the Snow Crab (Chionoecetes bairdi)
Authors: Hyning J. M. Van , Scarborough A. M.
Published: April 2011

A black encrustment commonly found on the exoskeleton of snow crabs (Chionoecetes bairdi) from the Gulf of Alaska has been identified as the microfungus Phoma fimeti. It appears unrelated to other described crustacean shell diseases.
A Gap Between Theory and Practice
Authors: Fukuda Y.
Published: April 2011

Under any pooled management scheme, such as the former Blue Whale Unit system for baleen whales, it is impossible, without appropriate technological developments, to attain the theoretical maximum sustainable harvest, that is, the sum of the maximum sustainable yields which single-species theory indicates is possible. Pursuit of this maximum is likely to result in overexploitation and stock failures. In general there can be a variety of alternative targets on a sustained basis.Regulation by area is worthy of consideration as one possible pooled management measure that will improve the sustainable harvest of the resources concerned. A set of the principles for valid area divisions is defined graphically and mathematically, although success depends on how well the proportion of each stock unit in the catch can be controlled by feasible area divisions.
Long-Term and Short-Term Fluctuations in the Catches of Coastal Pelagic Fisheries Around Japan
Authors: Nagasaki F.
Published: April 2011

Although the total landings of coastal pelagic fishes around Japan have been fairly stable for 10 years, the catch of individual species has shown violent fluctuations. The catch of Hokkaido herring and the sardine is decreasing and shows no signs of recovery. The catch of saury has also decreased sharply since 1960, but that of mackerel has increased substantially. There are big yearly fluctuations in the landings of squid, horse-mackerel, and anchovy, but no consistent trend either way has been shown. Apparently the great variations in stock abundance relate to the hydrographic complex in the waters around Japan. As most of the important coastal pelagic fishes spawn and spend their early life in the area of the continental shelf of the southern half of the Japanese islands, the location and the strength of the Kuroshio current play an important role in the ever-changing environmental conditions. Although the causes of these fluctuations are largely unknown, they can be classified as long, intermediate and short-term. The large-scale fluctuation over a long term, as in the case of the Hokkaido herring and the sardine, may possibly be due to evacuation of the main spawning grounds. The intermediate period of fluctuation is caused by the degree of survival of the young. A variety of causes must be responsible for the short-term fluctuation, including survival, for which there is no consistent trend, and the effect of the Kuroshio current on the distribution of the young fish.
Management of Sea Herring Fisheries in the Northwest Atlantic
Authors: Hennemuth R. C.
Published: April 2011

Regulatory measures for herring set by the International Commission for the Northwest Atlantic Fisheries (ICNAF) represent an important milestone in international fishery regulation because for the first time, they provide for national quotas in addition to a total catch limitation.The first regulatory measures were proposed in January 1972 to be effective that same year. In January 1973, the effects of the 1972 catch on the stock were evaluated, national quotas for 1973 were proposed, and conditional allowable catches for 1974 were proposed depending on stock size at the end of 1973. The 1972 catch, which according to preliminary statistics was within the total allowable catch, caused a further decrease in stock size. The effectiveness of the proposed 1973–74 quotas in increasing stock size depends on the sizes of the 1970 and 1971 year-classes entering the fishery in 1973 and 1974.Major problems in negotiating these regulations were caused by biological and socioeconomic factors. Biological factors included: population structure — several stocks involved, and parts of them are in nonconvention waters; assessment of effects of fishing — difficult because of rapid fishery development and because there are separate fisheries on adults and juveniles; fishery status — reductions up to 64% from 1971 catches required to prevent further spawning stock decreases. Socioeconomic factors included: allocation — general principles not previously applied, complications from new entrants, newly developing fisheries, and territorial-water fisheries; non-members; immediate action — normal procedures would prevent effective control in 1972; nonconvention waters — significant portions of the fishery not under ICNAF control; economic impact — severe reductions in existing fisheries and curtailment of developing national fisheries; administration — control technically difficult because of species and size mixture.Solutions to these problems arrived at by ICNAF are discussed, and seven general requirements for rational management are derived: adequate fishery statistics; assessment of effects of fishing; clearly defined objectives; workable techniques of regulation; principles for allocation; effective international inspection; effective enforcement.
Scientific Management of the World Stocks of Tunas, Billfishes, and Related Species
Authors: Joseph J.
Published: April 2011

This paper reviews past experience in tuna research and management, and proposes guidelines for the future. The resources discussed include three major groups: the six principal market species of tunas, which are heavily exploited; the billfishes, which are in most cases heavily exploited; and the secondary market species of smaller tuna and tuna-like fishes, which are generally underexploited. A brief review of their nomenclature, biology, and fisheries is given, followed by comments on the condition of the stocks. A discussion of institutional arrangements for the scientific study and management of tuna resources is presented, and such arrangements are examined in the light of problems which might be unique to tuna and tuna-like fishes. These special problems and ways in which they might be handled are considered.
Phenotypic Variation in the Lake Whitefish, Coregonus clupeaformis, Induced by Introduction into a New Environment
Authors: Loch J. S.
Published: April 2011

Adult lake whitefish (Coregonus clupeaformis) from Clearwater Lake and second generation adults of offspring from Clearwater whitefish transplanted to Lyons Lake were compared with respect to morphometric and meristic characters and isozymes of L-glycerol-3-phosphate dehydrogenase (GPDH). Feeding habits and abundance of pelagic and benthic foods were compared in the two lakes.Gill raker number, lateral line scale count, and interorbital width remained constant between parental and offspring populations. Gill raker length was the main character found to differ between the populations. This was found to be related to the percentage and type of benthic food eaten. Abrasion of the gill rakers is offered as an explanation for the differences in gill raker length. Differences were found in various other meristic and morphological characters, as well as in electrophoretic phenotype frequencies of isozymes of GPDH.
Composition minérale des écailles du Catostomus commersoni issu de deux milieux différents: étude par microscopie électronique analytique
Authors: Coillie R. van , Rousseau A.
Published: April 2011

The mineral content of scales, metals only, was studied. Fish of the Catostomus commersoni subspecies were used, taken from a healthy environment, (the Manicouagan River) and an environment polluted by, among other substances, various metals (Rivière des Prairies, near Montréal). X-ray microspectrometry was combined with electron microprobe scanning techniques, with subsequent microdensitometric scanning. Scales contained, in addition to the highly predominant calcium, the following: Na, Mg, Al, K, Fe, Cu, Zn, and Ba, as well as some Cr, Mn, Co, Ni, Sr, Ag, Cd, Cs, Hg, and Pb. All metals were between the circuli in the osteoid structures. The latter category of metals, widely known for their toxicity, were more abundant in the scales of the sample from polluted waters, whereas the reverse was true for the other metals, with the exception of Al and Ba, which were found in equal quantities in both samples. If the difference in content of the scales taken from fish of the two different environments is seen in relation with the fact that the toxic metals are more abundant in polluted waters and the fact that there is the possibility that excess metal from the water can replace calcium in the scales, we may infer that the mineral content of scales is related at least in part to that of the surrounding aquatic environment.
First Record from North America of the Piscicolid Leech, Ozobranchus margoi, a Parasite of Marine Turtles
Authors: Davies Ronald W. , Chapman C. G.
Published: April 2011

Ozobranchus margoi is recorded from North America for the first time, as an ectoparasite of the marine turtles Chelonia mydas mydas, Caretta caretta caretta, Eretomochelys imbricata imbricata, and Lepidochelys kempii. The pathology and treatment of the leech infestation are described and the presumed distribution of the species compared with that of Ozobranchus branchiatus, the only species of the genus previously recorded from North America.
Seasonal Variations of Temperature and Nutrients in the Surface Waters of Lakes Ontario and Erie
Authors: Gächter R. , Vollenweider R. A. , Glooschenko W. A.
Published: April 2011

During 1970, temperature and nutrient distributions were measured in surface waters of lakes Ontario (12 cruises) and Erie (10 cruises). Nutrient patterns are compared and discussed in relation to temperature, primary production, and nutrient sources.In Lake Erie, due to the early onset of the phytoplankton spring bloom, nutrient concentration started to decrease much earlier than in Lake Ontario. During spring, patterns of nutrients, chlorophyll a, and primary production were influenced by the thermal bar in Lake Ontario. In Lake Erie the nutrient supply controlled such patterns. In Lake Erie inorganic nutrients were depleted lake-wide in summer; in Lake Ontario, nutrients were highest in regions where upwelling occurred or inputs were high. Due to the earlier onset of fall overturn in Lake Erie, the nutrient concentration started to increase earlier in the fall than in Lake Ontario.
Geographical Distribution of Alleles for Supernatant Malate Dehydrogenase in Walleye (Stizostedion vitreum vitreum) Populations from Western Canada
Authors: Clayton J. W. , Harris R. E. K. , Tretiak D. N.
Published: April 2011

Walleye (Stizostedion vitreum vitreum) populations from western Canada contain three alleles for supernatant malate dehydrogenase (MDH). The protein subunits specified by these alleles produce isozymes that are readily distinguished by starch gel electrophoresis procedures. One of the MDH alleles (c1) appears to reach a maximum frequency of about 0.6 in the walleye populations of Crean and Montreal lakes, two headwater lakes in central Saskatchewan. The frequency of this allele declines to about 0.1 in populations only a relatively short distance downstream from these headwater lakes. In most walleye populations tested the c2 and c3 alleles predominate at frequencies between 0.2 and 0.7, whereas c1 is usually comparatively rare and occurs at a frequency of about 0.05.
A Method of Measuring Bacterial Growth in Aquatic Environments Using Dialysis Culture
Authors: Baskett Russell C. , Lulves William J.
Published: April 2011

An inexpensive, easy-to-use method was developed for studying microbial growth and behavior in situ. Dialysis tubing suspended from a styrofoam flotation ring was filled with sterile distilled water, placed in a farm pond, and inoculated with Brevibacterium sp. The viable population within the tubing increased significantly within 96 h, indicating that nutrients in the pond water necessary for growth and multiplication of Brevibacterium sp. diffused through the dialysis membrane.
Lipids and Fatty Acids of the American (Crassostrea virginica) and European Flat (Ostrea edulis) Oysters from a Common Habitat, and After One Feeding with Dicrateria inornata or Isochrysis galbana
Authors: Watanabe T. , Ackman R. G.
Published: April 2011

The oysters Crassostrea virginica and Ostrea edulis from a common habitat showed species-oriented fatty acid composition patterns for total lipids and lipid fractions. Attempts to modify these patterns by offering the unicellular algae Dicrateria inornata and Isochrysis galbana as food suggest that the oysters rapidly convert qualitatively or quantitatively unusual fatty acids to these species-oriented compositions, although only in the combination of D. inornata and O. edulis was enough fatty acid taken up to modify the oyster fatty acid composition in an easily detectable way. The unusual C22 nonmethylene-interrupted diunsaturated fatty acid components were not found in the O. edulis used for this study.
An Infestation of the Marine Fish Lycodes lavalaei by the Parasitic Copepod Tanypleurus alcicornis
Authors: Khan R. A. , Pitt T. K.
Published: April 2011

Three eelpouts, Lycodes lavalaei, with gills infested by the parasitic copepod Tanypleurus alcicornis (Caligoida: Tanypluridae) were collected on the Grand Banks off Newfoundland. As many as 42 parasites were recorded from one fish. The copepods caused extensive damage to the gill filaments. Anemia and emaciation were apparent in the infested fish.
Benthos and Allochthonous Organic Matter in Streams
Authors: Hynes H. B. N. , Kaushik N. K. , Lock M. A. , Lush D. L. , Stocker Z. S. J. , Wallace R. R. , Williams D. D.
Published: April 2011

Investigations into the vertical distribution of stream animals by means of a coring technique have demonstrated that they could be found many decimeters down in the gravel; a maximum of 17% was found in the top 5 cm.Sampling of arctic streams revealed that chironomid larvae comprised 70–80% of the numbers in the benthos and that their rate of drift did not vary with the time of day.Life history studies of stream invertebrates have demonstrated clear seasonal patterns in Canada. Work has been done on several mayflies and stone flies, some Chironomidae, and two species of Gammarus. Currently the life histories of the stone flies of southern Australia are being investigated in which the seasonality is much less marked.After the experimental application of the blackfly larvicide Methoxychlor to two rivers, a catastrophic drift of invertebrates occurred and larvicide residues were detected up to 8 wk after application.Work on the decomposition of autumn-shed leaves in water has included the responses to temperature and to additional nutrients (N and P). The effect of nutrient addition was to increase the amount of nitrogen in the leaf after incubation, but temperature affected only the rate of decomposition. Determination of the relative importance of bacteria and fungi in decomposition, was studied with use of antibiotics, and food preference of Gammarus for several leaf species was determined.A considerable portion (up to 40%) of the autumn-shed leaf is water-soluble, and the way in which it is made available to stream animals was investigated. One process, its conversion into particles, appears to involve mechanisms similar to those found in soils, i.e. by formation of organic/metal complexes. Using infrared spectroscopy, attempts have been made to characterize the laboratory and field-produced particles. Field investigations have also demonstrated large-scale fluctuations, during only a few hours, of dissolved and particulate organic matter in the water.These findings are considered in relation to general stream ecology.
Production of Zooplankton in Char Lake
Authors: Rigler F. H. , MacCallum M. E. , Roff J. C.
Published: April 2011

Production of the most abundant zooplankton in a polar lake was studied over 4 yr. Limnocalanus macrurus produced 261 mg m−2 yr−1 ash-free dry weight and Keratella cochlears produced 3 mg m−2 yr−1. Neither population fluctuated violently from year to year and mortality rates of both were low. Limnocalanus macrurus assimilation was equivalent to 73% of the annual planktonic primary production, and its respiration equal to 6% of the annual lake metabolism. Ciliated protozoa probably produce more than K. cochlearis, but far less than L. macrurus. Cross-calibration of sediment traps and zooplankton traps suggested that exuviae collected in sediment traps can be used to measure crustacean zooplankton production.
A Summary and Comparison of Nutrients and Related Water Quality in Lakes Erie, Ontario, Huron, and Superior
Authors: Dobson Hugh F. H. , Gilbertson Michael , Sly Peter G.
Published: April 2011

A summary is made, from recent data obtained by the Canada Centre for Inland Waters, of nutrients and water quality of offshore waters of the Great Lakes (excluding Lake Michigan). A simple indexing system, based on a limited number of variables, is used to describe related water quality.
Crustacean Plankton Communities of 340 Lakes and Ponds in and near the National Parks of the Canadian Rocky Mountains
Authors: Anderson R. Stewart
Published: April 2011

The crustacean plankton communities of 340 lakes and ponds in southern Alberta and southeastern British Columbia were examined. The waters are situated between 660 m and 2455 m in elevation, have areas from < 0.1 to 3940 hectares, and range from 0.5 m to 136 m in depth. They represent a wide range of salinities, from 2 ppm to 29,800 ppm. The communities were grouped into seven main types on the basis of the copepod species present. Of the 97 crustacean species present, 32 were copepods, 50 were cladocerans, and 9 were anostracans. The three most common species accounted for over 25% of the total species occurrences. Only two species were present in more than half the total lakes and ponds. A few species seem to be restricted to highly saline waters, and a few to low salinities, but most inhabited a wide range of aquatic environments. The most frequently occurring and abundant species tolerate a wide range of conditions. These species are also characterized by up to a fivefold variation in generation time. Certain species having restricted distribution patterns appear to be limited by both the chemistry of the water and the heat content. Aspects of species distribution, ecology, and interspecific relationships are discussed.