bluuebunny/crossref_metadata_2025 huggingface dataset:
The Morphology, and Some Observations on the Population Genetics of Anisakis simplex Larvae (Nematoda: Ascaridata) from Fishes of the North Atlantic
Authors: Beverley-Burton Mary , Nyman O. L. , Pippy John H. C.
Published: April 2011

The morphology of larval Anisakis simplex in a subsample taken from Atlantic herring, Clupea harengus harengus, in the North Sea (and used in previous in vitro culture experiments) is described, with particular reference to the excretory system.The morphological similarities of these larvae from C. harengus harengus and Atlantic salmon, Salmo salar, taken in widely separated locations in the North Atlantic suggests that Anisakis larvae Type 1 is A. simplex. These findings are substantiated by studies on acid phosphatase polymorphism of the larvae and the known geographic ranges of related species. Frequencies of the acid phosphatase phenotypes varied in different sampling areas, suggesting that different populations of larval A. simplex occur in fish in the North Atlantic.
Genetic Differences in Growth and Survival of Juvenile Hatchery and Wild Steelhead Trout, Salmo gairdneri
Authors: Reisenbichler R. R. , McIntyre J. D.
Published: April 2011

Relative growth and survival of offspring from matings of hatchery and wild Deschutes River (Oregon) summer steelhead trout, Salmo gairdneri, were measured to determine if hatchery fish differ genetically from wild fish in traits that can affect the stock–recruitment relationship of wild populations. Sections of four natural streams and a hatchery pond were each stocked with genetically marked (lactate dehydrogenase genotypes) eyed eggs or unfed swim-up fry from each of three matings: hatchery × hatchery (HH), hatchery × wild (HW), and wild × wild (WW). In streams, WW fish had the highest survival and HW fish the highest growth rates when significant differences were found; in the hatchery pond, HH fish had the highest survival and growth rates. The hatchery fish were genetically different from wild fish and when they interbreed with wild fish may reduce the number of smolts produced. Hatchery procedures can be modified to reduce the genetic differences between hatchery and wild fish.
Vital Statistics and Migratory Patterns of a Potamodromous Stock of Smallmouth Bass, Micropterus dolomieui
Authors: Robbins William H. , MacCrimmon Hugh R.
Published: April 2011

Between 1968 and 1971, upriver movement of bass from Lake Simcoe was highly correlated with water temperature and discharge (r = 0.704, P <.001). Vital statistics and growth were similar to lacustrine and riverine stocks at similar latitude. Total annual mortality averaged 0.56 with 65% attributable to angler exploitation, principally in the river. Some 34% (after mortality) river spawners returned upriver in subsequent years. Repeat spawners (65% female) comprised an average 19% of the spawning runs. Most adults moved downriver in late June and July when water temperatures approached 25 °C. Adults remaining in the spawning area experienced water temperatures to 29 °C before emigrating during freshets in July and August. Lake migrants intermingled on shoal areas with lacustrine and possibly other potamodromous stocks each summer.
Population Dynamics and Marine Mammal Management Policies
Authors: Eberhardt L. L. , Siniff D. B.
Published: April 2011

Some criteria for appraising population level relative to the maximal or carrying capacity point are listed. Simple population-dynamics models are then used to explore some of the criteria. Age at first reproduction does not seem as important as in some more prolific and shorter-lived species, being at most equivalent to a few percentage points of adult survival. Age-specific reproductive rates are very much the same for a number of pinniped species. For most marine mammal species, survival through immature stages is an unknown quantity, but appears to be a factor of major importance in determining population trend. Data on the Pribilof fur seals (Callorhinus ursinus) lead to the speculative conclusion that the maximum sustained yield (MSY) point may be to the right of the median value frequently assumed, so that "optimal" population levels may be closer to the asymptotic or carrying capacity level. Such a view is proposed as a conservative management policy.
Host–Parasite Relationships Between Sockeye Salmon, Oncorhynchus nerka, and Salmincola californiensis (Copepoda: Lernaeopodidae)
Authors: Kabata Z. , Cousens B.
Published: April 2011

The distribution of the parasitic copepod, Salmincola californiensis, on two size-groups (fry, fork length 3.2–5.8 cm; juveniles, fork length 10.2–27.0) of the sockeye salmon, Oncorhynchus nerka, is described. The existence of preferred sites for both groups is established. The distribution on the smaller fish differs from that on the larger in that on the former the copepods are most abundant in the region of pectoral and pelvic fins, whereas on the latter they are by far most common in the branchial cavity. Macroscopic and microscopic mechanical damage to the fish tissues, resulting from the presence and activity of the copepod, comprises injuries to gills, skin, muscle, and even bone. The "burrowing phenomenon" (failure on the part of the copepod to cease excavation of a completed cavity of implantation, resulting in perforation of body wall and penetration of the viscera) is reported upon for the first time.
Heinz Body Hemolytic Anemia in Coho Salmon (Oncorhynchus kisutch) Exposed to Chlorinated Wastewater
Authors: Buckley James A.
Published: April 2011

Fingerling coho salmon (Oncorhynchus kisutch) were exposed for 12 wk to various concentrations of treated wastewater containing total residual chlorine (TRCl2) with riverwater diluent under continuous flow conditions. Levels of TRCl2 averaging 0.003–0.05 mg/ℓ resulted in mild to pronounced symptoms of hemolytic anemia, including an increase in numbers of circulating immature erythrocytes, pathological changes in erythrocytes, and a reduction in packed cell volume and hemoglobin levels. In addition, Heinz bodies were formed at the 0.012 and 0.05 mg/ℓ TRCl2 levels. The hematologic changes were attributed to the oxidative nature of TRCl2.
Life Histories of Cricotopus (Cricotopus) bicinctus and C. (C.) mackenziensis (Diptera: Chironomidae) in the Fort Simpson Area, Northwest Territories
Authors: Rosenberg David M. , Wiens Allen P. , Sæther Ole A.
Published: April 2011

Cricotopus (Cricotopus) bicinctus (Meigen) and C. (C.) mackenziensis Oliver emerge from June to September in the Fort Simpson area, Northwest Territories. Cricotopus bicinctus begins and ends emerging later than C. mackenziensis. Cricotopus bicinctus apparently produces a mixture of two and three generations per year, whereas C. mackenziensis apparently produces three generations per year. Both species overwinter mainly in the second instar. Emergence data from other studies, when reevaluated, appear to underestimate the number of generations produced by C. bicinctus, indicating a similar number of generations as in the Fort Simpson area.
Egg and Larval Survival of White Suckers (Catostomus commersoni) at Low pH
Authors: Trojnar John R.
Published: April 2011

White sucker (Catostomus commersoni) eggs were incubated in water of high (250 μmhos/cm) and low (20 μmhos/cm) conductivity with nominal pH ranging from 4.2 to 8.0. At pH 4.5 and below in water of low conductivity no eggs survived to hatching. In high conductivity water at pH 4.5 a few prolarvae hatched but were deformed and soon died. At pH 5.0 and above the total hatch was the same at either conductivity level. However, at pH 5.0 there were body deformities and abnormalities in the vascular system and none of the prolarvae survived to the swim-up stage. At both conductivity levels there was a reduction in swim-up at pH 5.3 compared with the control, but none at pH 5.8. Low pH had a delaying influence on the absorption of the yolk sac.
Rapid Chromosome Preparations from Solid Tissues of Fishes
Authors: Kligerman Andrew D. , Bloom Stephen E.
Published: April 2011

A technique is described for obtaining well-spread metaphases from solid tissues of fishes without the use of methodologies that rely on tissue grinders, centrifuges, digestive enzymes, or tissue culture. This procedure involves the formation of a cell suspension from acetic alcohol fixed tissues using 50% acetic acid. The suspension is applied to a warm (50 °C) slide using a micropipette.Solid tissue preparations may be stained by any of the conventional dyes or treated to reveal Q-bands, C-bands, and nucleolar organizers. Large numbers of slides offish chromosomes can be made easily and rapidly using this procedure.
Sex Ratio of American Eels, Anguilla rostrata, from the Matamek River System, Quebec, with Remarks on Problems in Sexual Identification
Authors: Dolan J. A. , Power G.
Published: April 2011

The failure to examine gonadal tissue of American eels, Anguilla rostrata, histologically could result in considerable errors in sexual identification. Two "organs of Syrski", usually considered to be the male testes, and several small, ribbon-like gonads, generally thought to indicate female ovaries, revealed contradictory results when sectioned histologically. Other sources of error in determining a representative sex ratio of eels were noted. In the Matamek River system, Quebec, the range in length at which gonadal formation commenced was considerable. Male eels were rare (5 of 613 fish), which is consistent with other reports for the northern limits of this species.
Physical and Chemical Characteristics of Aquatic Humus
Authors: Povoledo D.
Published: April 2011

not available
The Fishes of Missouri.
Authors: Gerking S. D.
Published: April 2011

not available
Statistical Assessment of the Age–Length Key
Authors: Kimura Daniel K.
Published: April 2011

Since 1934 when Fridriksson originated the age–length key, it has been widely used by fisheries biologists to estimate age distributions of populations. In recent years, there has been a general recognition that often the key has little value, or even worse, gives biased results. The analysis presented here indicates why the age–length key is so susceptible to bias. More importantly, a criterion is presented for determining whether the age–length key should be used in a particular situation. If the key is to be used, results from examples indicate that random age subsamples (i.e. the number of specimens aged from each length category proportional to the number in each length category) are superior to fixed age subsamples (i.e. a constant number of specimens aged from each length category). Generally, small increases in the age sample will likely increase the accuracy of an age-distribution determination more effectively than relatively large increases in the length sample.
Daily Rings in Otoliths of Three Species of Lepomis and Tilapia mossambica
Authors: Taubert Bruce D. , Coble Daniel W.
Published: April 2011

Daily rings formed on otoliths of known-age, laboratory-raised pumpkinseed (Lepomis gibbosus), green sunflsh (L. cyanellus), bluegill (L. macrochirus), and mozambique mouthbrooder (Tilapia mossambica) for at least 176, 170, 125, and 60 days, respectively. Subdaily rings found in young laboratory and wild fish were easily distinguished from daily rings. Width of daily rings on otoliths of green sunfish was linearly related to daily increase in length of fish, but the number of rings was a product of age of fish only, not length of fish or otolith radius. Growth and daily ring formation on otoliths in wild bluegill and largemouth bass (Micropterus salmoides) appeared to be similar to those in laboratory-raised fish. Otoliths of green sunfish held under simulated winter conditions ceased to produce daily rings, but did form an annulus. Two kinds of otolith tissue were present in most of the larger laboratory fish and wild bluegill but were not observed in wild largemouth bass. The first type, present in all areas of the otolith except the extreme posterior end, was translucent and had well-defined daily rings. The second type, present only in the posterior end, was opaque and had poorly etched daily rings that were difficult to discern. Both tissues were calcium carbonate in the aragonite form. Daily rings were found on otoliths offish held at constant temperature. Results of experiments with young mouthbrooders held under various light–dark and feeding cycles suggested that a 24-h light–dark cycle that entrained an internal, diurnal clock was required for daily ring production.
Hydrocarbons in Eastern Canadian Marine Waters Determined by Fluorescence Spectroscopy and Gas–Liquid Chromatography
Authors: Keizer P. D. , Gordon Jr. D. C. , Dale J.
Published: April 2011

Concentrations of n-alkanes ranged from <20 ng/ℓ to about 1 μg/ℓ at depths of 2 and 50 m. Estimated oil concentrations based on fluorescence analyses ranged from 0.2 to 9.3 μg/ℓ. The highest concentrations occurred in Bedford Basin; the similarity of fluorescence contour plots to petroleum products and the presence of unresolved envelopes in chromatograms suggest that a large portion of the hydrocarbons in the Basin are derived from oil. Hydrocarbons in other regions appear to be principally biogenic in origin. Key words: Oil detection, northwest Atlantic, gas–liquid chromatography, fluorescence spectroscopy
Habitat Partitioning in a Freshwater Fish Community
Authors: Werner Earl E. , Hall Donald J. , Laughlin Dennis R. , Wagner Donald J. , Wilsmann Leni A. , Funk Frederick C.
Published: April 2011

The patterns of habitat utilization in the littoral zone fish community of two small southern Michigan lakes were examined. Abundance and habitat use of the fish were quantified by underwatertransect censuses. The sunfishes (Centrarchidae) dominated the communities numerically and by weight, with two species, the bluegill (Lepomis macrochirus) and largemouth bass (Micropterus salmoides) accounting for 85% of the community biomass. Spatial (habitat) segregation of species was evident along gradients of depth (distance from shore), vertical height in the water column, and vegetational structure. Several species showed intraspecific differences in the spatial distribution of size-classes. Comparative analyses of habitat use in the two lakes suggest that small size-classes are confined by predation to areas of dense cover and that within these areas competition determines space utilization by different species. The patterns of habitat use are discussed in relation to the food habits and morphology of species in this community. Only one clear case of segregation of two species by food size occurs (bass and bluegill); most other species segregate predominantly by habitat. The rarer centrarchids show strong niche complementarity with the codominant bass and bluegill.
Modèles linéaires de prédiction des débarquements de homard aux Iles-de-la-Madeleine (Golfe du Saint-Laurent)
Authors: Boudreault F.-Robert , Dupont J.-Normand , Sylvain Claudine
Published: April 2011

Annual lobster landings (1912–74) at the Magdalen Islands can be represented with the Box and Jenkins method, by a first order autoregressive model which explains 41.9% of the total variance. Analysis of fishing effort and surface temperature yields, through a regression on principal components, a linear model that includes the first and makes use of the December temperature [Formula: see text] ago and that of the winter [Formula: see text] ago. This prediction model explains 84.4% of the total variance. The biological interpretation is as follows: annual landings depend on available stock, on the influence of temperature on the survival probability of larvae and possibly, on a similar influence on the probability of access to sexual maturity of the 5-yr-old class.
Pleistocene Watershed Exchanges and the Fish Fauna of the Peel River Basin, Yukon Territory
Authors: Bodaly R. A. , Lindsey C. C.
Published: April 2011

The Peel River basin is a unique Canadian glacial refugium containing many relict fish populations. Peel River is presently tributary to the Mackenzie River system, but at least twice during Pleistocene glaciations it was diverted into headwaters of the Yukon River system, offering the possibility of two-way transfer of aquatic organisms between the Mackenzie and Yukon. Present fish distributions in the Peel basin are summarized. Biochemical and morphological evidence suggests that races of at least six species now inhabiting the area (Coregonus clupeaformis, Prosopium coulteri, Thymallus arcticus, Salvelinus namaycush, Esox lucius, Cottus cognatus) originated from types which either came from the Yukon River system or developed in situ in unglaciated parts of the Peel.
Filamentous Algae as a Food Source for the Brown Bullhead (Ictalurus nebulosus)
Authors: Gunn J. M. , Qadri S. U. , Mortimer D. C.
Published: April 2011

Studies of food habits of the brown bullhead (Ictalurus nebulosus) in the Ottawa River have often shown a high proportion of filamentous algae in the stomach. This study was designed to determine whether the algae were utilized as food. Isotopic and caloric techniques showed that about 23% of the carbon from Spirogyra and 67% of the carbon from Anaebena flos-aquae was assimilated by the fish within 24 h of ingestion.
Nitrogen Fixation (Acetylene Reduction) Associated with Sea Urchins (Strongylocentrotus droebachiensis) Feeding on Seaweeds and Eelgrass
Authors: Guerinot M. L. , Fong W. , Patriquin D. G.
Published: April 2011

Sea urchins feeding in different macrophyte zones in St. Margaret's Bay, Nova Scotia, in November and December 1975 were examined for nitrogenase activity using the acetylene reduction technique. For sea urchins feeding on Laminaria digitata and L. longicruris, the average rate of acetylene reduction was equivalent to N2 fixation of 55 μg N2 per sea urchin per day assuming a 3:1 molar ratio of C2H2 reduction to N2 fixation. Lower nitrogenase activities were observed for sea urchins feeding on Agarum cribrosum and Zostera marina, and no nitrogenase activity was observed for sea urchins taken from bare rock substrate on which kelp had been absent for 4 yr. Samples of separated digestive tracts but not the degutted bodies of sea urchins exhibited nitrogenase activity, suggesting that the digestive tract is the site of nitrogen fixation in whole sea urchins.
Therapeutic Treatment for Epibiotic Fouling on Dungeness Crab (Cancer magister) Larvae Reared in the Laboratory
Authors: Fisher William S. , Nelson Richard T.
Published: April 2011

This study shows that larvae of the Dungeness crab (Cancer magister Dana) reared in the laboratory are susceptible to epibiotic microbial infestation similar to that described for eggs of the same species. Larval survival in the laboratory was increased by increased additions of antibiotics to the sea water; however, the chemotherapeutic agent, malachite green, was unsuccessful due to its toxicity to the sensitive larval stages. The addition of the diatom Phaeodactylum tricornutum was beneficial to larval survival in the light but detrimental in dark conditions, supporting the suggestion of a photosynthetic excretion from the algae capable of antibiotic activity. Chronic antibiotic treatment was observed to reduce the size of the larvae. Demonstration of larval susceptibility to epibiotic microbial infestation in the laboratory coupled with its occurrence on egg stages in nature provides reasonable evidence that the disease can occur on larval stages in nature.
Production of the Euphausiid Crustacean Thysanoëssa raschii in the Gulf of St. Lawrence
Authors: Berkes F.
Published: April 2011

From field data on growth and population numbers, production of Thysanoëssa raschii, excluding molts, was calculated to be about 1.8 mg dry wt∙m−3∙yr−1 in the Gulf of St. Lawrence. The mean annual biomass of T. raschii was 0.47 mg dry wt∙m−3, comprising about 1% of the total zooplankton biomass in the Gulf, and giving a production to biomass (P:B) ratio of about 4. Production and biomass were probably underestimated due to some sampler avoidance, lack of egg to nauplius–metanauplius interval of population production and loss of weight due to leaching in preserved samples.
Eel Capture, Culture, Processing and Marketing.
Authors: Eales J. G.
Published: April 2011

not available
Fishery and Reproductive Cycle of the Red Sea Urchin, Strongylocentrotus franciscanus, in British Columbia
Authors: Bernard F. R.
Published: April 2011

Gametogenesis and gonadal index undergo an annual cycle with minima in September and maxima in May for a population of red urchins, Strongylocentrotus franciscanus, from southwestern Vancouver Island. Postspawning recovery is rapid and there are no significant differences between male and female gonadal indices, but a small gonad to body-size correlation is evident. Gonadal index is not the product of gametogenesis, but is correlated to glycogen accumulation which may reach 13% gonad total weight. The fishing season for roe in southern British Columbia extends from October to April with several weeks variability depending on local conditions and weather. Yields constitute up to 25% total drained weight. Key words: urchins, fishery, gametogenesis, glycogen, hermaphroditism, sex ratio
Lymphocystis Disease in Yellowfin Sole (Limanda aspera) in the Bering Sea
Authors: Alpers C. E. , McCain B. B. , Myers M. S. , Wellings S. R.
Published: April 2011

A study to determine the prevalence of fish disease in the Bering Sea revealed lymphocystis disease in yellowfin sole (Limanda aspera). The gross pathology and histopathology of typical nodules are described. Electron microscopic studies revealed characteristic icosahedral lymphocystis virus particles, as well as clusters of intracellular structures of uncertain origin. This study begins a larger effort to understand the effects of an altered marine environment upon the biology of lymphocystis virus infection in the Bering Sea. Key words: lymphocystis, pleuronectids, yellowfin sole, Bering Sea, flatfish.
Reexamination of the Carotenoid Pigments of the Unicellular Blue-green Alga Agmenellum quadruplicatum
Authors: Antia N. J. , Cheng J. Y.
Published: April 2011

A previous claim for the occurrence of antheraxanthin and the absence of typical cyanophycean xanthophylls in Agmenellum quadruplicatum has been disproven. This phycocyanin-producing prokaryote showed chlorophyll a, β-carotene, zeaxanthin, one myxoxanthophyll-like, and one myxol-like carotenoid as the major pigments. Traces of keto and other carotenoids were observed, one of which appears to be phoenicopterone or a cis-echinenone. No antheraxanthin and chlorophyll b or c were detected under all culture conditions tested. Algal chlorosis from culture aging was caused by the consecutive loss of phycocyanin and chlorophyll, but the carotenoid composition was much less affected and there was no gain of secondary or keto carotenoids. We concluded that this alga is a typical member of the Cyanophyceae in terms of pigment chemotaxonomy.
Effects of Diet, Ambient Temperature, and Holding Conditions on Plasma Thyroxine Levels in Rainbow Trout (Salmo gairdneri)
Authors: Leatherland J. F. , Cho C. Y. , Slinger S. J.
Published: April 2011

Rainbow trout (Salmo gairdneri) acclimated to 19 °C and fed a pelleted diet of either 6% soybean oil or 6% tallow fat had similar plasma thyroxine levels (0.62 ± 0.10 and 0.69 ± 0.08 μg/100 ml, respectively), although fish acclimated to 7 °C and fed the soybean diet gave significantly (P < 0.05) higher plasma thyroxine concentration (1.32 ± 0.13 μg/100 ml) than the group fed the tallow fat diet (0.95 ± 0.12 μg/100 ml). The plasma thyroxine concentration in the fish fed the soybean oil diet was significantly (P < 0.01) higher at 7 °C than at 19 °C. There was no significant difference between the two groups of fish given the tallow fat diet. Epithelial cell heights were largest in groups with the highest plasma thyroxine levels. Epithelial cell height in the two groups at 19 °C were similar, but in both groups of fish at 7 °C, the cell height was significantly greater than in either of the groups at 19 °C (P < 0.01 for comparisons of the 19 °C tallow fat diet with both groups of 7 °C acclimated fish and comparison of the two groups on the soybean oil diet; P < 0.05 for comparisons of the 19 °C, soybean oil diet with the group held at 7 °C and given the tallow fat diet). Fish deprived of food for 40 days had a significantly (P < 0.05) lower plasma thyroxine concentration when compared with fish that had been fed daily. There was no significant diurnal variation in plasma thyroxine over the light phase of a 12 h light: 12 h dark photoperiod, nor did the limitation of light entering the aquaria significantly affect plasma thyroxine values. Key words: endocrine, thyroid, Salmo gairdneri, diet, environmental temperature
Factors Affecting the Stability of Supplemental Ascorbic Acid in Practical Trout Diets
Authors: Hilton J. W. , Cho C. Y. , Slinger S. J.
Published: April 2011

The stability of L-ascorbic acid in practical trout diets that had been processed by several different methods was investigated. Coated ascorbic acid was more stable to autoclaving than the fine-powdered form, but losses due to water addition, "cold" pelleting, and drying were approximately 90% with or without first autoclaving the diet. Increasing the level of supplemental coated ascorbic acid increased absolute losses but permitted retention of a significant level in the feed for a longer period of time. The shelf life of processed trout diets is dependent on the type of processing, storage temperature, and moisture content of the diet. Laboratory-processed diets stored at room temperature lost all the supplemental ascorbic acid within 6 wk. Commercially processed diets had less processing losses than the laboratory-processed diets, but storage losses were still severe. Freezer-stored diets had minimal losses while diets stored at room temperature were below NRC requirements after 5 wk (steam-pelleted diet) and below this level after 8 wk (extruded diet) when both were initially supplemented with 400 mg/kg feed. Key Words: ascorbic acid, trout diets, vitamin stability, processing stability, storage stability, vitamin requirements trout
Survival of American Lobsters (Homarus americanus) Stored in a Recirculating, Refrigerated Seawater System
Authors: Cornick John W. , Stewart James E.
Published: April 2011

Conditions required for the extended survival of American lobsters (Homarus americanus) in a recirculating, refrigerated seawater system were investigated with a unit incorporating a biologically "conditioned" sand filter with and without activated carbon. Lobsters held at a temperature of 5 °C and a density of 50g/ℓ of water for periods up to 60 days without water change experienced < 10% mortality when activated carbon was incorporated into the filter; without the carbon, mortalities were in excess of 20%. The reduced mortalities with carbon were not related to lower levels of accumulating un-ionized ammonia (toxic form) in the water but were attributed to an inhibition of buildup of acid substances in the water, thereby maintaining pH levels above 7.5.
Temperature Preference Studies in Environmental Impact Assessments: An Overview with Procedural Recommendations: Introduction
Authors: Richards F. Paul
Published: April 2011

not available
Temperature as a Proximate Factor in Orientation Behavior
Authors: Reynolds William W.
Published: April 2011

Temperature serves as a proximate factor (cue, guidepost, sign stimulus, or directive factor) affecting locomotor responses of fishes. Although temperature can also serve as an ultimate ecological factor, as in behavioral thermoregulation, nonthermal factors may in some cases provide the ultimate adaptive or ecological value of a temperature response; some examples are habitat selection, intraspecific size segregation, interspecific niche differentiation, isolating mechanisms, predator avoidance, prey location, escape reactions, and migrations (thermoperiodic, diel, seasonal, spawning). Conversely, nonthermal variables such as light intensity or water depth may act as accessory proximate factors in thermoregulation. In spawning migrations, thermal requirements of eggs and larvae may take precedence over the (often different) preferenda or optima of adults. Although thermal responses of fishes are largely innate and species specific, ontogenetic and other changes can occur. Since temperature can serve as an unconditioned reinforcer in operant conditioning, thermal responses are not limited to simple kineses or taxes. Nonthermal factors such as photoperiod, circadian rhythms, currents, social and biotic interactions, stresses, infections, or chemicals can affect thermal responses, and may account for some lack of conformity between laboratory preferenda and field distributions and behaviors. Key words: thermoregulation, orientation, preferendum, selection, preference, avoidance, behavior, temperature, fish, responses
Compilation of Temperature Preference Data
Authors: Coutant Charles C.
Published: April 2011

This report briefly summarizes current information from field and laboratory studies on temperature selection by fishes, with a tabulation of final temperature preferenda and upper and lower avoidance temperatures. Key words: temperature, selection, preferendum, avoidance, preference, behavior, orientation
Laboratory Methods for Determining Temperature Preference
Authors: McCauley Robert W.
Published: April 2011

Different types of temperature-gradient devices used in the laboratory to determine temperature preferences of fish are classified and reviewed. The type of device used seems to have less effect on experimental results than do other variables such as age, size, season, physiological state, or social interactions. Key words: preferred temperature, thermal gradients, thermoregulation, behavioral, gradient devices, laboratory techniques
The Coast and Shelf of the Beaufort Sea.
Authors: Giovando L. F.
Published: April 2011

not available
Survival in Toxic Environments.
Authors: Greer G. L.
Published: April 2011

not available
Public Health Aspects of "Codworm" Infection: A Review
Authors: Margolis L.
Published: April 2011

Larvae of the nematode Phocanema decipiens (Ascaridida: Anisakidae), known as "codworm" in the vernacular, occur in the musculature of some cod and other marine fishes in both hemispheres, particularly in the temperate and polar climatic zones. The natural definitive hosts are Pinnipedia (seals, sea lions, walruses). For many years regarded incapable of surviving in man, recent reports from Japan indicate that in certain circumstances codworm larvae may temporarily invade the human gastric mucosa, producing clinical symptoms. Several nonclinical cases, in which the larval worms were expelled orally or in the feces of humans, have been reported from Canada (1), the USA (5), Greenland (1), and the U.K. (1). The source of human infections was raw, lightly marinated, or insufficiently cooked sea fish. The ability of codworm larvae to penetrate the stomach wall of other mammals has been demonstrated experimentally in rabbits, rats, dogs, and pigs. Natural infection of a dog in Hokkaido has been reported. For the human cases, information on age and sex of patients, specific source of infection, symptoms, and gross pathology are reviewed. The name applied to human infections and their diagnosis, treatment, prognosis, prevention, and public health implications are discussed. Cooking at 70 °C for 7 min or 60 °C for 10 min and freezing at −20 °C for 24 h are lethal to codworm larvae in fish flesh, thus providing reliable methods for preventing human infections. Some comparisons are made with larval Anisakis infections in man and future research needs, particularly in relation to the public health question, are discussed.
Availability of Atmospheric Orthophosphate
Authors: Peters Robert Henry
Published: April 2011

Phosphoais fractions in 15 samples of rain, rain plus dust, or snow were analyzed to shed light on the role of aeolian P in the nutrient budgets of lakes. Total Plevels varied (6.6 to 122.4 μg P/ℓ) but were generally high (mean = 47.0 μg P/ℓ; 76% of this was dissolved. Biologically available orthophosphate comprised an average of 38% of the total. Neither soluble reactive P nor small molecular weight P eluting with 32P-PO4 in gel filtration were consistently adequate estimates of orthophosphate concentrations. Key words: nutrient budgets, orthophosphate, phosphorus, bioassay, rain
Reconstruction of Yellow Perch (Perca flavescens) Cohorts from Examination of Walleye (Stizostedion vitreum vitreum) Stomachs
Authors: Forney John L.
Published: April 2011

Number of young perch (Perca flavescens) consumed by walleye (Stizostedion vitreum vitreum) in Oneida Lake was determined from analysis of feeding chronology and digestion rates. Young perch were ingested between sunset and sunrise and digestion rates were estimated from the decrease in weight of perch in stomachs during the day. Walleye prédation began in late June and by October the number of young consumed ranged from 17,940 to 242,900 ∙ha−1 in 1971–73. Concurrent studies indicated an additional 590 to 56,130 young were eaten by adult perch.Minimum population of young perch in June was calculated by adding to the number of young that survived to fall, the number consumed by walleye and adult perch. Populations reconstructed in this manner approximated independent estimates of the pelagic population in June. Mortality of young perch was apparently attributable to predation by percids and reconstructed populations accurately portrayed seasonal trends in abundance of young perch. Key words: predation, walleye, yellow perch, digestion, mortality
Organochlorine Residues in Maternal Blubber, Milk, and Pup Blubber from Grey Seals (Halichoerus grypus) from Sable Island, Nova Scotia
Authors: Addison R. F. , Brodie P. F.
Published: April 2011

Residues of DDT group insecticides and of PCBs were measured in samples of maternal blubber, milk, and pup blubber from grey seals (Halichoerus grypus) from Sable Island, N.S. Mean ΣDDT and PCB levels in maternal blubber lipid were 14.0 and 14.5 μg/g, respectively. Concentrations of DDT and PCBs in milk lipid were approximately 60 and 30%, respectively, of those found in maternal blubber lipid, suggesting a partial barrier to passage of these residues through mammary tissue. Concentrations in pup blubber lipid were the same as, or slightly higher than, those in milk lipid.We estimated that a grey seal will lose about 30% of its total ΣDDT burden and about 15% of its PCB burden through lactation; this would be approximately balanced by its estimated annual intake of these residues from food. Thus, the observation that female seals show no increase in residue burdens with age (in contrast to males) is explained. Key words: organochlorine, DDT, DDE, PCB, seal, blubber, milk
Dynamics of an Exploited Population of Lake Whitefish (Coregonus clupeaformis)
Authors: Bell Graham , Handford Paul , Dietz Carl
Published: April 2011

The life history of the exploited lake whitefish (Coregonus clupeaformis) population of Lesser Slave Lake, Alberta, is described. Mean age is high, having increased under continued exploitation during the last 30 yr. A method of estimating the population age structure is described. The apparent annual rate of survival of adult fish has fluctuated markedly, but on average seems to lie in the interval 0.40–0.50; the annual rate of natural survival is estimated to be 0.53. Juveniles survive better than adults. Rate of survival during the 1st yr of life was estimated to be about 0.0002. Maturity was late, the median age at first reproduction being 6–61/2 yr. The regressions of fecundity on age and length are described; length now contributes almost all the attributable variance to maturity and fecundity. The sex ratio fluctuates in time; this is caused by the fluctuations in age structure, since sex ratio varies with age. The relationship between sex ratio and age is used to calculate the relative rates of survival of male and female fish.These data are used to construct a life table and to compute population parameters. It is inferred that the ability of the population to respond to exploitation has been eroded during the last 30 yr. In some respects, the life history of the Lesser Slave Lake stock appears to be unusual.After about 30 yr of large-amplitude oscillation the whitefish population collapsed in 1965. This does not seem to have been caused by chronic overfishing. In the first place, the rate of fishing mortality is no more than moderate. Secondly, a multiple regression equation describing whitefish catch in 48 other Alberta lakes in which there has been no overall decline in catch successfully predicts the observed mean catch at Lesser Slave Lake. The oscillations in catch are claimed to reflect a limit cycle in the abundance of the whitefish, driven by a lagged relationship between a predator (the fishermen) and its prey (the whitefish). Whether or not this cycle was deterministically stable, such behavior will inevitably put the population in risk of extinction during troughs in the cycle. We suggest that current management policies may encourage the destabilization of whitefish populations, and we propose a remedy. Key words: population dynamics, population regulation, life history, exploitation, survival, fecundity, Coregonus clupeaformis
Crustacean Zooplankton Communities as Indicators of Limnological Conditions An Approach Using Principal Component Analysis
Authors: Sprules W. Gary
Published: April 2011

Principal component analysis is used to develop a technique for predicting the limnological characteristics of a lake from knowledge of its midsummer limnetic crustacean zooplankton community. Patterns of variation in zooplankton community structure are summarized in the principal components extracted, via the species covariance matrix, from the matrix of transformed proportionate numerical abundances of species in a sample of lakes. The relation between these patterns and the limnological characteristics of the lakes is determined from the first-order rank correlations of the limnological variables with the components. In relatively undisturbed lakes of northwestern Ontario, results indicate that lakes characterized by Cyclops bicuspidatus thomasi, Diaptomus minutus, and others are large and clear, whereas those characterized by Tropocyclops prasinus mexicanus, D. oregonensis, and others are smaller and of lower water clarity. These patterns are contrasted with those extracted from the same data using more subjective techniques. In the acid-stressed Killarney region, Ontario, lakes dominated by D. minutus are predicted to be acidic, small, and clear, whereas those dominated by Diaphanosoma leuchtenbergianum, Bosmina longirostris, Mesocyclops edax, and others will be less clear, larger, and with higher pH. In Haliburton lakes, Ontario, those with Diaptomus oregonensis, M. edax, and Ceriodaphnia lacustris are predicted to be small and productive, whereas those with D. minutus, D. sicilis, B. longirostris, and Daphnia dubia will be larger and less productive. The usefulness of the technique and some modifications are discussed. Key words: zooplankton communities, principal component analysis, ELA lakes, Haliburton lakes, Killarney lakes
Growth Model for Alaska King Crab (Paralithodes camtschatica)
Authors: McCaughran Donald A. , Powell Guy C.
Published: April 2011

A stochastic growth model is presented to represent the growth in carapace length of the Alaska king crab (Paralithodes camtschatica Tilesius). Two submodels are combined to yield the growth model: (1) growth increment as a function of premolt length and molting history and (2) a probabilistic model of frequency of molting by age, premolt length, and molting history. The results of a computer simulation of the growth model are presented. Frequency of ages at various lengths and frequency of lengths at each age are given. Frequency of molting during early life was found to greatly influence growth rate. Key words: king crab, growth, length, stochastic model growth increment, molting, growth model
Plankton Dynamics and Nutrient Enrichment of the Scotian Shelf
Authors: Fournier Robert O. , Marra John , Bohrer Richard , Det Mary Van
Published: April 2011

Four seasonal cruises were conducted on a 270-km-long transect normal to the coast of Nova Scotia. Most biological variables measured along this transect show maximum values in the outer 90 km. These maxima usually occur closely associated with an oceanic front which is a consistent feature of this region. Enhanced vertical transport of nutrients is postulated to occur along this front, although the mechanism is unknown. A model proposed several years ago to explain shelf enrichment off the northeastern United States was examined and found to be consistent with the Scotian Shelf data. Sporadic advection of nutrient-rich Slope Water onto the shelf at the average rate of 0.33 cm∙s−1 would, upon entering the euphotic zone, satisfy 20% of phytoplankton nutrient requirements during the spring and summer. Recycling would account for the remaining 80%. Key words: phytoplankton, zooplankton, enrichment, Scotian Shelf, excretion, fronts, nutrients, productivity, advection, recycling
White Sucker (Catostomus commersoni) Embryo Development, and Early Growth and Survival at Different Temperatures
Authors: McCormick J. Howard , Jones Bernard R. , Hokanson Kenneth E. F.
Published: April 2011

White suckers (Catostomus commersoni) were exposed from fertilization through hatching to seven constant temperatures from 6.2 through 24.1 °C. High percentages of apparently normal larvae hatched at temperatures from 9.0 through 17.2 °C. Maximum percent hatch occurred at 15.2 °C, while only a few normal larvae were produced at 6.2 °C, and none at 24.1 °C.Growth rates increased from near zero at 10.0 °C to a maximum at 26.9 °C. At 29.7 °C growth fell below the maximum (P < 0.05), and the incidence of spinal deformities was high. Death rates were uniformly low from 15.7 to 26.9 °C and were significantly higher at 10.0 and 29.7 °C (P < 0.05). The rate of net biomass gain for test groups was maximum at 26.9 °C. Net rates of biomass gain declined progressively with temperatures below 26.9 °C until by 10.0 °C the rate of population growth became less than the rate of weight loss through deaths within the population. The temperature producing maximum hatching success, 15 °C, was nearly 12 °C lower than that providing for maximum growth and net biomass gain.Upper thermal 1-, 2-, and 7-day TL50 values for both newly hatched and swim-up larvae, when acclimated to 9 and 10 °C, were between 28 and 29 °C. When acclimated to 15 and 21 °C, they were between 30 and 32 °C.Lower 1-day TL50 temperature values for both groups of larvae acclimated to 21 °C were near 3 °C (< 2.9), 2-day TL50 values were approximately 0.5 °C higher, and 7-day values were 4.8 °C for newly hatched larvae and 6.1 °C for swim-up larvae.
Food of Some Benthic Harpacticoid Copepods
Authors: Brown T. J. , Sibert J. R.
Published: April 2011

Feeding rate of harpacticoid copepods on different food sources was measured using a double isotope technique. Heterotrophically derived carbon was ingested at a rate 9 times faster than autotrophically derived carbon.
A Hand-Operated Suction Sampler for the Collection of Subtidal Organisms
Authors: Tanner C. , Hawkes M. W. , Lebednik P. A. , Duffield E.
Published: April 2011

A hand-operated suction sampler is described for use by SCUBA divers. The sampler is simple in construction and compact in size, and it provides a means by which diminutive benthic algae, invertebrates, or fish may be collected. Key words: algae, benthic organisms, sampling device, SCUBA, suction sampler
Effect of Shock Exposures of Chlorine on the Plasma Electrolyte Concentrations of Adult Rainbow Trout (Salmo gairdneri)
Authors: Zeitoun Ibrahim H. , Hughes Leroy D. , Ullrey Duane E.
Published: April 2011

Blood was pooled from randomly selected 3-yr-old rainbow trout (Salmo gairdneri) before addition of chlorine to their water environment and afterward when fish began to gulp for air and lose equilibrium. In five duplicate tests, plasma concentrations of phosphorus, magnesium, iron, copper, zinc, and potassium increased substantially in the stressed fish. Calcium concentration was also higher, but not significantly so in the plasma of the test fish as compared with those of the controls. Sodium was the only electrolyte that dropped substantially (P < 0.01) in the test fish as compared with the controls.Chlorine toxicity appeared to disturb the mineral homeostasis in the fish blood. Rapid recruitment of electrolytes from the environment and movement into the plasma, a strong mineral retention mechanism, or mobilization of body mineral stores worked together or individually to compensate for those minerals lost with water during hemoconcentration. Key words: rainbow trout, plasma electrolytes, chlorine, hemolysis, hematology, toxicology
Perca fluviatilis in Australia: Zoogeographic Expression of a Life Cycle in Relation to an Environment
Authors: Weatherley A. H.
Published: April 2011

Perca fluviatilis was introduced into Australia during the nineteenth century. Its extensive distribution in Australia and the range of climatic and topographic conditions over which it occurs make it possible to distinguish the roles of high temperature, breeding conditions, and flow characteristics in rivers in limiting the spread of the species. By extrapolation the distributional limits of the species throughout the world can be largely explained and, by analogy, those of the closely related species P. flavescens in North America. A model of a fish life cycle arising out of knowledge of Perca life cycles is presented as a possible tool for clarifying and predicting the success or failure of species introduced into new environments. Key words: Percidae, Perca, zoogeography, life history, introduction in Australia, predictive model, management, Eurasian perch
Effects of Ambient Light Variations on Behavior of Yearling, Subadult, and Adult Walleyes (Stizostedion vitreum vitreum)
Authors: Ryder R. A.
Published: April 2011

All facts when ordered and synthesized with previously published information suggest that light is the principal abiotic controlling variable of the environment that determines temporal and spatial dimensions of feeding and reproduction in the walleye, Stizostedion vitreum vitreum. Underwater observations during the day revealed that adult walleyes were active in turbid regions of a lake but rested in contact with the substrate in clear-water regions. In the latter instance physical shelter served to shield the eyes of the walleyes from the ambient light. An inverse relation was noted between numbers of walleyes sighted per hour of transect swum and transparency levels of the water. In experimental angling during the open-water season, the total number of walleyes captured and the catch per unit of effort were positively related to illuminance levels. Winter angling through the ice showed a similar relationship, though at percentage light transmission levels one order of magnitude lower. Percentages of walleyes captured per [Formula: see text] increment during openwater at dusk were positively related to percentage decrease in illuminance for the same time intervals and inversely related to absolute levels of illuminance. Other authors have determined that nuptial activity also, and hence reproduction, is governed by variations in the ambient light regime. Key words: Stizostedion vitreum vitreum, walleye, light, behavior, photopic vision, tapetum lucidum, turbidity, preferred habitat, scotopic vision, feeding pattern