bluuebunny/crossref_metadata_2025 huggingface dataset:
Modified Oxidation/Fermentation Medium for Use in Identification of Bacterial Fish Pathogens
Authors: Walters G. R. , Plumb J. A.
Published: April 2011

A medium, designated glucose motility deep (GMD), was developed to determine motility, oxidation, fermentation, and gas production of gram-negative, cytochrome oxidase positive, bacterial fish pathogens in one culture tube. The medium is intended to replace the current glucose oxidation–fermentation test which requires two tubes and a petrolatum overlay. Isolates of Aeromonas hydrophila, A. salmonicida, Pseudomonas fluorescens, Vibrio anguillarum, and Pasteurella piscicida were inoculated into GMD. The oxidation–fermentation metabolism, motility, and gas production of each isolate agreed with results obtained using conventional methods. Key words: bacteriology, bacterial medium, fish disease, fish pathogens, Aeromonas, Pseudomonas, oxidation/fermentation, identification
Characterization of Particulate Organic Matter Transported by Some Cascade Mountain Streams
Authors: Naiman R. J. , Sedell J. R.
Published: April 2011

Field and laboratory studies were conducted to characterize concentrations, factors determining concentrations, particle size composition, and presumed food quality of particulate organic matter (POM) transported by streams of four different orders in Oregon's Cascade Mountains. Devils Club Creek (first order) and Mack Creek (third order) as high gradient, heavily shaded headwater streams receive large amounts of forest debris. Lookout Creek (fifth order) and the McKenzie River (seventh order) have lower gradients and more organic inputs from in situ aquatic primary producers and organic matter drifting from upstream areas than from the adjacent forest. Concentration of particulate organic matter is low during periods of nonstorm discharge, and not significantly related to stream power or type of organic input. All streams transport a mean POM particle size < 12 μm. Over 70% of all particulate organic matter transported is very fine particulate organic matter (VPOM: 0.45–53 μm). Except for spring, the ratio of coarse (> 1 mm) to fine (0.45 μm–1 mm) organic matter (CPOM:FPOM) is near zero, but remains elevated for the McKenzie River during all seasons. As determined by the amount of chlorophyll, carbon to nitrogen (C:N) ratio, percentage of organic matter and respiration rate, the presumed food quality of drifting organic matter is potentially better in downstream reaches. Key words: food quality, detritus, organic matter, streams, rivers, watershed, drift, transport
Entrainment of Larval Fish by the Douglas Point Generating Station, Lake Huron, in Relation to Seasonal Succession and Distribution
Authors: Kelso John R. M. , Leslie John K.
Published: April 2011

Larval fish were sampled by net in Lake Huron and the Douglas Point generating station throughout spring, summer, and early fall 1975. Dominance shifted from fourhorn sculpin (Myoxocephalus quadricornis) to rainbow smelt (Osmerus mordax) then to ale-wife (Alosa pseudoharengus) from late April to late September. Entrainment of the major species paralleled dominance and abundance observed in the lake, but yellow perch (Perca flavescens), brook stickleback (Eucalia inconstans), and slimy sculpin (Cottus cognatus) caught in the lake — each ranging from 5 to 25% of the total catch — were not entrained. Conversely, white sucker (Catostomus commersoni) was entrained but not captured in the lake. Size of individuals entrained, upper limit approx. 40 mm, paralleled size of individuals in the lake. Vertical distribution, and thus proximity to the submerged intake, greatly influenced entrainment rate. Key words: larval fish, entrainment, power plant, distribution, abundance.
Precocious Sexual Development in Hatchery-Reared and Laboratory-Maintained Male Steelhead Trout (Salmo gairdneri)
Authors: Schmidt Steven P. , House Edwin W.
Published: April 2011

The incidence of precocious steelhead trout (Salmo gairdneri) was determined in several Idaho hatchery steelhead populations. The range of incidence of precocious males was 0–64% of the sampled populations. This variation appeared to be related to age of the trout, water temperature, and photoperiod. The incidence of precocious males greatly exceeded the incidence (0.1% of the population when encountered) of precocious females. Precocious male steelhead trout are apparently lost from the migrating smolt population and display mating behavior similar to sea-run adult male steelhead. Precocious males maintained in laboratory conditions remained sexually mature for at least 6 mo of observation. This was reflected by mean gonadal weights and mean gonadosomatic indices from precocious male steelhead which differed significantly from nonprecocious juvenile male steelhead maintained under similar conditions. No consistent pattern of growth was observed among laboratory-maintained trout. Key words: steelhead trout, reproduction, precocious sexual maturation, age, photoperiod, temperature
Disease Diagnosis and Control in North American Marine Aquaculture. Developments in Aquaculture and Fisheries Science, 6.
Authors: Stewart James E.
Published: April 2011

not available
Introductory Dynamic Oceanography.
Authors: Clarke R. Allyn
Published: April 2011

not available
Fluctuations of Chlorophyll and Related Physical Parameters in British Columbia Coastal Waters
Authors: Wiegand R. C. , Pond S.
Published: April 2011

Continuous horizontal profiles of chlorophyll, temperature, salinity, and oxygen were made at three depths and in three locations in British Columbia coastal waters, and spectra and cross spectra calculated. Generally, fairly strong relationships exist between chlorophyll and temperature and salinity, especially at scales of order 10–1000 m. However, the relationships are not always expressed through the same physical parameter. It is apparent from coherence and phase data that in a turbulent environment the vertical profiles of the parameters are important in determining the nature of the relationships. Average spectra show power law relationships similar to the results of other authors. Key words: chlorophyll, temperature, salinity, oxygen fluctuations; surface coastal waters; T, S, O2, chlorophyll fluctuations; spectra and cross-spectra of T, S, O2, chlorophyll; measurements of T, S, O2, chlorophyll in surface waters
Differences in the Age of Pacific Hake (Merluccius productus) Using Whole Otoliths and Sections of Otoliths
Authors: Beamish R. J.
Published: April 2011

Ages determined for older Pacific hake from sections through the nucleus of otoliths were older than the ages determined from the otolith surface for the two populations studied. Growth of all parts of the otolith was not identical throughout the life of the fish. The change in the pattern of otolith growth occurred about the age at which the growth in length of the fish was reduced. Despite the disproportionate growth in length and height of the otolith, the thickness of the otolith, especially in the ventral interior portion, continued to increase with age. Section ages appear to be more reliable for older fish because of this allometric change in otolith growth with increasing fish age. It is suggested that the examination of sections of otoliths should become a routine approach in any attempt to age fish using otoliths. Key words: age determination, otolith, otolith section, otolith growth, aging errors, Pacific hake, Strait of Georgia
Estimating Chlorophyll Extraction Biases
Authors: Stauffer R. E. , Lee G. F. , Armstrong David E.
Published: April 2011

A simplified chlorophyll analytical procedure is described that requires 4 min/sample and features an overall precision (measured by the coefficient of variation, C.V.) of ~ 3% at the 15 mg/m3 chlorophyll a level. The C.V. varies inversely with concentration for spectrophotometric determinations. The molar extinction coefficients (665 nm) for chlorophyll a were estimated to be 2.5–6.0% greater in acetone (90%) compared to methanol (100%) and 2.5% greater in a 1:1 mixture (v/v) of methanol-dimethyl formamide compared to methanol. Acetone (90%) extractions of naturally occurring mixtures of the common bloom-forming blue-green algae Microcystis, Oscillatoria, Aphanizomenon, and Anabaena yielded erratic recoveries of chlorophyll a. The lowest recovery (34%) occurred with an Oscillatoria population. On the one occasion when a four-way solvent extraction comparison was performed, acetone (90%) failed to extract 29 ± 2% of the chlorophyll a in a mixture of Anabaena, Microcystis, and Aphanizomenon, whereas the other three solvent preparations yielded identical (complete) extractions. Methanol or acetone-dimethyl sulfoxide are recommended for chlorophyll extraction from blue-green algae, while acetone-dimethyl sulfoxide is recommended for diatoms or Chlorophyta populations. Key words: chlorophyll, Cyanophyta, Chlorophyta, chlorophyll analysis, methanol, acetone, methanol-dimethyl formamide, acetone-dimethyl sulfoxide
Twilight Activities of Yellow Perch, Perca flavescens
Authors: Helfman Gene S.
Published: April 2011

Underwater observations were made on the diel activity patterns of yellow perch (Perca flavescens) in Cazenovia Lake, Madison County, New York (42°56′N, 75°52′W). Perch underwent a characteristic progression of activities during dusk at relatively predictable light levels and times. Patterns within the progression included increased swimming, last feed, group breakup, slowdown, and final stop. Activity at sunrise was the reverse of the sunset sequence except that some activities occurred at lower light levels than did the analagous activities in the evening. Differences exist in the twilight activity patterns of perch in different lakes; within a lake, both ontogenetic and subpopulation differences are also observed. These differences may be responses to ecological conditions, such as relative predation levels, or they may reflect the extreme plasticity of the species. Key words: behavioral ecology, changeover, diel, diurnal, fish, light, nocturnal, ontogeny, plasticity, temperate lake
Spectral and Biochemical Characteristics of the Particulate Matter in Bedford Basin
Authors: Mayzaud P. , Taguchi S.
Published: April 2011

A survey of the distribution, nature, and biochemical composition of particulate matter (less than 153 μm diam) showed that small particles (< 18 μm) made up the bulk of the particulate matter during most of the summer. Relatively large amounts of microzooplankton (tintinnids) were also recorded during the period of stable hydrographic conditions. Diatoms and dinoflagellates were abundant only in early fall prior to the fall bloom. All cell counts were transformed into parts per million on a volume basis to compare with Coulter Counter data. Cell counts on preserved samples strongly underestimated the number and volume of small particles and did not take into account the detritus. Considerations of the ATP content strongly suggested that for naturally occurring particulate matter there is not a constant ATP to carbon ratio but rather an upper and lower limit. Small particles were the main repository for protein whereas phytoplankton was the repository for carbohydrates. The high variability of both quality and quantity of particles in the neritic habitat suggests that a single chemical variable cannot describe fully the nutritive value of naturally occurring suspended matter. Key words: particulate matter, phytoplankton, microzooplankton, flagellates, protein, carbohydrates, ATP, carbon
Immersion Vaccination of Sockeye Salmon (Oncorhynchus nerka) with Two Pathogenic Strains of Vibrio anguillarum
Authors: Gould R. W. , Antipa R. , Amend D. F.
Published: April 2011

Sockeye salmon (Oncorhynchus nerka) were immersion-vaccinated in suspensions containing 5 × 107, 5 × 106, 5 × 105, or 5 × 104 bacteria/mL of bivalent or monovalent, formalin-killed Vibrio anguillarum, Types I and II. The fish were split into two lots and held for 54 d. At that time one lot was challenged with living, virulent V. anguillarum, Type I, and one with living, virulent V. anguillarum, Type II. Immunization with bivalent bacterin effectively protected the fish from vibriosis, but monovalent vaccine was effective only against the homologous challenge. Immunization with the highest concentration of Type I monovalent bacterin resulted in 0% Type I and 58% Type II challenge mortality. Immunization with the highest concentration of Type II monovalent bacterin resulted in 41% Type I and 0% Type II challenge mortality. Immunization with the highest concentration of bivalent Type I/Type II bacterin resulted in 2% mortality in both challenges. Protective bacterins were effective at concentrations down to 5 × 105 bacteria/mL. Key words: immersion vaccination, bivalent vaccines, Vibrio anguillarum, vibriosis
Influences of Diet on the Life Histories of Aquatic Insects
Authors: Anderson N. H. , Cummins Kenneth W.
Published: April 2011

Benthic species are partitioned into functional feeding groups based on food-acquiring mechanisms. Effects of food quality on voltinism, growth rate, and size at maturity are demonstrated for representatives of gougers and shredders, collectors, and scrapers. Food quality for predators is uniformly high, but food quantity (prey density) obviously influences their life histories. A food switch from herbivory to predation, or some ingestion of animal tissues, in the later stages is a feature of the life cycle of many aquatic insects. Temperature interacts with both food quality and quantity in effects on growth as well as having a direct effect on control of metabolism. Thus further elaboration of the role of food in life history phenomena will require controlled field or laboratory studies to partition the effects of temperature and food. Key words: aquatic insects, feeding strategies, functional groups, life histories
Benthic Life Histories: Summary and Future Needs
Authors: Waters T. F.
Published: April 2011

The symposium indicated many ways in which greater knowledge of benthic life histories can be used to develop and improve techniques such as sampling, taxonomic methods, and bioassays. Benthic organisms' diet and physical environment, factors variable in nature, were shown to be capable of modifying certain life history features such as growth rate and voltinism. The lack of accumulated life history data and the need to tailor sampling schedules to life history events were commonly identified elements in the symposium. Future research needs included (1) basic data on benthic life history, (2) improved taxonomy of immature benthic invertebrates, and (3) understanding the entire life history of an organism in relation to the seasonal progression of its environment. Management implications of benthic life history information included more applicable data from long-term bioassays on all life history stages, and improved management of stream fisheries through habitat alteration to manipulate benthic production. Key words: life history, benthos, symposium
Optimal Survey Design: Lessons from a Stratified Random Sample of Macrobenthos
Authors: Cuff W. , Coleman N.
Published: April 2011

A stratified random sample of macrobenthos in Western Port (Victoria, Australia) provided adequate data to take an a posteriori look at the efficiency of various random survey designs in terms of their ability to provide precise estimates of the mean number of individuals per taxon, i.e. mean estimates with the smallest possible variance. Emphasis was placed on the efficiency of the stratified simple random sampling design. The analyses showed that bay-wide estimates resulting from various stratified designs would not have been substantially more precise than those from simple random sampling. This conclusion was not influenced by the allocation strategy used in the stratified design. On the other hand, substantial gains in precision could have been made, for the same total number of grab samples, by increasing the number of stations at the expense of the number of grab samples per station. Our data suggested that the optimal number of grab samples per station is only one, contrary to the common practice of multiple grab samples per station. Key words: stratified, random, survey, optimal, macrobenthos, sample, Western Port
Sensitivity Analysis of Two Harp Seal (Pagophilus groenlandicus) Population Models
Authors: Mohn R. K.
Published: April 2011

Sensitivity analysis has been used to estimate the relative importance of input parameters both between and within two harp seal (Pagophilus groenlandicus) population models. The population size at maximum sustainable yield is shown to be much more poorly defined than the yield level itself. Key words: sensitivity analysis, harp seal, population model, sustainable yield, management
Coastal Resources Management.
Authors: Cauvin Dennis M.
Published: April 2011

not available
Studies on the Sediment of St. Margaret's Bay, Nova Scotia
Authors: Hughes T. G.
Published: April 2011

A detailed examination of the sediment in a small area of St. Margaret's Bay revealed it to be composed of two main types of particles, mineral particles and particles of organic debris. Debris was also adsorbed onto the mineral particles. Particles generally had relatively low numbers of bacteria associated with them indicating that most of the organic carbon in the sediment is refractory. Variation in size distribution of the component particles with depth in the sediment was found to be minimal, but a slight decrease in the proportion of debris particles was seen. Variation in size distribution along a transect was also limited, but where the mineral particles became coarser the size range of the debris particles remained constant. The relative amount of debris particles along the transect varied little but values for total organic carbon (by weight) changed dramatically. Key words: sediment, particle composition, size distribution, organic carbon
Possible Adaptive Significance of Certain Enzyme Polymorphisms in Steelhead Trout (Salmo gairdneri)
Authors: Redding J. M. , Schreck C. B.
Published: April 2011

In experimentally reared winter steelhead trout (Salmo gairdneri) fry, mean weights, lengths, and condition factors of three isozyme phenotypes of lactate dehydrogenase (LDH) enzyme differed significantly. Time of emergence from the gravel was unrelated to LDH phenotype. Relative mortality of the phenotypes between eyed-egg stage and emergence was unaffected by different subgravel conditions of temperature and dissolved oxygen. Differential tolerance to acute challenges of high temperature and low dissolved oxygen was observed between phenotypes of isocitrate dehydrogenase (IDH) enzyme and LDH in juvenile trout. Parental effects may have biased the result for LDH. Differences between IDH phenotypes may be related to intrinsic properties of variant isozymes. Key words: isozymes, lactate dehydrogenase, isocitrate dehydrogenase, temperature, dissolved oxygen, adaptive significance, Salmo gairdneri
Infectious Pancreatic Necrosis Virus: Quantification of Carriers in Lake Populations During a 6-Year Period
Authors: Yamamoto T. , Kilistoff J.
Published: April 2011

An infectious pancreatic necrosis (IPN) carrier population of brook trout (Salvelinus fontinalis) planted in an isolated natural lake was tested for virus over a period of 6 yr. The initial isolation rate of 90% had decreased to 50% during this period indicating that there is a prolonged persistence of virus in infected animals of this species. The ceca with the associated pancreatic tissue of these fish yielded virus most frequently during the early years but the virus then decreased to low levels. Kidneys were the most consistent organs to yield virus throughout the study period. The feces yielded little virus at first but later increased for several years and then decreased. The spleen and liver yielded virus infrequently. Surgically removed gonads were the least frequent yielders of virus. The low virus isolation rate from progeny of the carrier population and from other planted fish indicated that transmission in the wild is probably infrequent. Other lakes with normal angling that had plantings with IPN carrier fish but subsequently planted annually with disease-free fish had populations whose carrier rate had decreased to undetectable levels within a 6-yr period. These findings indicated that the practice of planting IPN-free fish into areas where carriers were previously introduced may lead eventually to a carrier-free state. Key words: infectious pancreatic necrosis virus, Salvelinus fontinalis, virus persistence, carrier fish, virus isolation rate
Short-Term Covariability of Chlorophyll and Temperature in the St. Lawrence Estuary
Authors: Demers S. , Lafleur P. E. , Legendre L. , Trump C. L.
Published: April 2011

Time series of chlorophyll a fluorescence and temperature taken at a depth of 1 m were recorded at 4-min intervals for 136.5 h, at an anchor station located in the Middle Estuary of the St. Lawrence. The sampling program was carried out during the transition from neap tides to spring tides. Power spectral analysis was applied to the series and variance spectra were estimated. Coherency spectra between fluorescence and temperature were also computed. Results indicate that chlorophyll distribution was controlled by physical processes during neap tides. Conversely, lesser amounts of chlorophyll a per cell and lesser primary production rates were noted during spring tides. A flattening of the chlorophyll spectrum was observed for this part of the study. This result was interpreted in terms of the poor physiological state of the phytoplankton population that was sampled during the second part of the study, a different density structure being present due to the change in tidal energy. Key words: time series, chlorophyll, temperature, spectral analysis, St. Lawrence Estuary
Acute Ammonia Toxicity and Ammonia Excretion in Rainbow Trout (Salmo gairdneri)
Authors: Hillaby Betty A. , Randall David J.
Published: April 2011

Acute ammonia toxicity in rainbow trout (Salmo gairdneri) was studied by intraarterial injection of NH4Cl and NH4HCO3. Hydrogen ion and total ammonia concentrations were measured in blood sampled from the dorsal aorta both before and after injection. Although injection of NH4HCO3 increased arterial blood pH, and injection of NH4Cl decreased arterial blood pH, the same dose of each was required to kill fish. While the un-ionized form of ammonia in water has been shown to be toxic, in the blood either the ionized form or the total ammonia load is toxic to fish. Ammonia levels were measured in pre- and postbranchial blood. Mean values were not significantly different, but paired values indicated a fall in blood ammonia due to excretion across the gills. There appears to be a more rapid excretion of ammonia following NH4HCO3 infusions, which result in higher un-ionized ammonia levels in blood compared with those following NH4Cl infusions. These results are consistent with the hypothesis that ammonia is excreted in the un-ionized form. Key words: un-ionized ammonia, ionized ammonia, gills, pH, blood
Intertidal Catastrophes: Effect of Storms and Hurricanes on Intertidal Benthos of the Minas Basin, Bay of Fundy
Authors: Yeo R. K. , Risk M. J.
Published: April 2011

Hurricane Beulah (July 1975) and a major storm both caused catastrophic mortalities among intertidal benthos of the Minas Basin. In both events, surface sediment was scoured off the flats, resulting in high mortalities in shallow-burrowing organisms. The storm was a more severe catastrophe than the hurricane. The demonstrated high secondary productivity of these flats is difficult to reconcile with these observations; extensive lateral migration of the benthos may aid in recovery from catastrophes. Key words: benthos, intertidal productivity, Bay of Fundy, tidal power, catastrophes, Macoma balthica, Corophium volutator
Chronic Exposure of Trout to Waters with Naturally High Selenium Levels: Effects on Transfer RNA Methylation
Authors: Kaiser Ivan I. , Young Patricia A. , Johnson Jerry D.
Published: April 2011

Liver tissues from rainbow (Salmo gairdneri) and brown (S. trutta) trout chronically exposed to waters with naturally high selenium levels accumulate significant amounts of the element, with values in the 50–70 μg/g range (fresh tissue) not unusual. This accumulation appears to increase with time since older fish from the same waters invariably contain higher liver selenium levels. Studies in other systems suggested that there might be gross alterations in cellular macromolecular methylations in fish chronically exposed to elevated selenium levels. Mature tRNAs isolated from trout livers having both low and high selenium levels, however, showed no differences in their methyl-accepting abilities in a homologous in vitro methylating system. In addition, direct nucleoside analyses on these different tRNA samples showed similar levels of base methylation, with no evidence for methylation abberations. The nucleoside analyses on the tRNAs were similar and in keeping with values reported for other eukaryotic systems. Key words: selenium, biological methylation, methylation, transfer RNA, nucleoside analysis, Salmo gairdneri, S. trutta
Power Plant Entrainment. A Biological Assessment.
Authors: Kelso John R. M.
Published: April 2011

not available
Biology of benthic organisms. 11th European Symposium on Marine Biology, Galway, October, 1976.
Authors: Sibert John R.
Published: April 2011

not available
Impact of Canada's Pacific Salmon Fleet Control Program
Authors: Pearse Peter H. , Wilen James E.
Published: April 2011

The available statistical data are analyzed to appraise the success of Canada's Pacific salmon fleet rationalization program, in terms of the extent to which it has prevented fishing costs from rising in pace with the value of the catch. It is found that while the fleet's revenues increased at about the same rate before and after the scheme was introduced in 1969, the real capital employed increased more slowly under the controls than earlier. The program has, nevertheless, failed in its purpose of preventing further expansion of redundant capital in the fleet. The reasons for this failure, and for certain apparent shifts in the structure of the fleet, are discussed. Key words: Pacific salmon fishery, capitalization, economic rationalization, resource rent
Alaska's Experience with Limited Entry
Authors: Adasiak A.
Published: April 2011

The goals and structure of the limited entry program in Alaska were defined by the political, social, economic, and biological climates in which the program was implemented. This paper outlines how these considerations formed the program and discusses the impacts of the program and the problems involved in its implementation. Other possible modes of approaching entry limitation are discussed in relation to the possibility of limiting some currently unlimited fisheries.
Perspectives on Fisheries Biology and Implications for Management
Authors: Dickie L. M.
Published: April 2011

Descriptions of fisheries systems for purposes of management often seem to imply a naturally predetermined biological structure and functioning of the resource. However, such basic characteristics as stock definition, species composition, levels of production, and biological efficiency are parameters that have generally been adapted to suit particular fishery conditions and in any case are variables that interact with both environment and the nature of industrial exploitation. In the interests of economic or social analyses in fisheries these biological descriptors should normally be amenable to redefinition or redescription without prejudice to their reliability as indices of natural production. Key words: fisheries management, economic objectives, unit stock concept, variability, fisherman's choice, predator–prey relations, biological and technological efficiency
Sabellidae (Polychaeta) Principally from the Northeast Pacific Ocean
Authors: Banse Karl
Published: April 2011

Morphological and distributional observations are reported for 14 northeast Pacific sabellids, largely using collections from British Columbia and Washington waters, and for one species from New Zealand. For nine of these, additions to the descriptions are provided based on type material. Eudistylia Bush is revised using a new combination of diagnostic characters. Eudistylia catharinae is newly described; E. tenella Bush is regarded as a synonym of E. vancouveri (Kinberg). Diagnostic characters at the generic level, particularly those of Sabella Linnæus, are discussed. Demonax Kinberg, considered to be a subgenus of Sabella, is emended. Distylia volutacornis pacifica Berkeley and Berkeley is elevated to specific rank and referred to Demonax. Jasmineira pacifica Annenkova, Oriopsis gracilis Hartman, and an unnamed species of Sabellastarte Savigny are new additions to the polychaete fauna of British Columbia and Washington. Key words: British Columbia, Demonax, Eudistylia, northeast Pacific, Polychaeta, Sabella, Sabellidae, Washington
The Source of Muddy Odor in Bream (Abramis brama) from the Porvoo Sea Area (Gulf of Finland)
Authors: Persson Per-Edvin
Published: April 2011

The study area was a shallow, extremely eutrophic, somewhat brackish water bay on the south coast of Finland. Muddy odor in bream (Abramis brama) was significantly correlated with the amount of the blue-green alga Oscillatoria agardhii occurring in the phytoplankton. Cultures dominated by this alga contained the muddy odor compound geosmin. The high concentrations of O. agardhii in the study area were caused by several interacting factors, of which the high nutrient concentration and the temperature of the water seemed to be especially important. Odoriferous actinomycetes isolated from the water produced the muddy odor compounds geosmin and 2-methylisoborneol, but there seemed to be a lag time of several weeks between maximal concentrations of actinomycetes and development of off-flavors in the fish. Key words: geosmin, 2-methylisoborneol, Oscillatoria agardhii, actinomycetes, flavor, fish, eutrophication
Concentrations and Kinetics of Phosphorus Fractions Along the Trophic Gradient of Lake Memphremagog
Authors: Peters Robert Henry
Published: April 2011

Published relationships between chlorophyll and total phosphorus concentrations show that the amount of chlorophyll developed per unit of total P increases as total P increases. If the availability of phosphorus changes with lake trophy, this should be reflected in the proportion of total P found in different analytical fractions. From June 1975 to September 1976, the concentrations of total phosphorus, soluble phosphorus, orthophosphate, large molecular weight phosphorus (> 5000 mol wt) and small molecular weight phosphorus (< 400 mol wt) were measured at six sites along the phosphorus-production gradient of Lake Memphremagog; 32P-PO4 was used to follow short-term exchanges between available orthophosphate and other fractions. Total P declined threefold among sites but the proportion of different fractions remained relatively constant which suggests that any disproportionate loss from one compartment is made good by exchanges with the others. On average, soluble P formed\of total P, soluble reactive phosphorus formed 14%, and PO4 8%; gel filtration showed that ~40% of soluble P was associated with large molecular weight phosphorus and ~40% with small molecular weight phosphorus. Within this basic similarity, was a trend to decreased PO4 concentrations and increased concentrations of soluble P and soluble unreactive phosphorus at more oligotrophic sites. Tracer experiments showed that all fractions exchanged some P with 32P-PO4, although soluble fractions, especially large molecular weight phosphorus, interacted more slowly with orthophosphate than did particulate P. Faster orthophosphate turnover suggested greater P deficiency in more oligotrophic sites. This deficiency may promote the formation of a refractory soluble P which may explain a part of the reduced ratio of chlorophyll to phosphorus when total P is reduced. Key words: orthophosphate, phosphorus, turnover, availability, lakes, gel fitration, soluble organic P
Oxygen Depletion and Winterkill Risk in Small Prairie Lakes Under Extended Ice Cover
Authors: Barica Jan , Mathias John A.
Published: April 2011

Mean rates of dissolved oxygen depletion in 10 shallow eutrophic prairie lakes (area 2.3–27.3 ha, mean depth 1.6–4.2 m), ranged from 0.22 to 0.34 g/m2∙d−1 for nonstratified lakes and 0.32–0.42 g/m2∙d−1 for stratified ones. An average rate for all lakes was 0.29 ± 0.06 g/m2∙d−1. The rates correlated with the lake depth. A method for estimating the winterkill risk on the basis of initial oxygen storage, rate of dissolved oxygen depletion and/or the mean or maximum lake depth is proposed. Key words: prairie lakes, oxygen depletion rates, winter fish kill, eutrophication, metabolism, oxygen storage
Temperature Preference of Several Species of Salmo and Salvelinus and Some of Their Hybrids
Authors: Peterson R. H. , Sutterlin A. M. , Metcalfe J. L.
Published: April 2011

Temperature preference of newly feeding fry of two species of Salmo, three species of Salvelinus, and seven hybrids were determined in a horizontal gradient. Fry of species in the genus Salmo and intergeneric hybrids with female parent in Salmo selected significantly higher temperatures (13.0–15.0 °C, P < 0.05) than did fry of species and hybrids of the genus Salvelinus (9.0–11.5 °C). No significant differences were obtained among species and hybrids within either of the two groups described above. Preferred temperatures of fingerlings (after 3 mo of feeding) of two species and two hybrids within Salvelinus were determined in a vertical temperature gradient. Brook trout preferred 17.5 °C, and lake trout 10.8 °C. The two hybrids (brook trout × lake trout and lake trout × brook trout) preferred intermediate temperatures (14.7 and 14.4 °C). Rainbow trout fingerlings selected 14.7 °C. Key words: temperature, preference, Salmo, Salvelinus, hybrids, gradients
Growth and Mortality of the Blue Mussel (Mytilus edulis) in Relation to Environmental Indexing
Authors: Freeman K. R. , Dickie L. M.
Published: April 2011

Comparative production estimates of selected species may provide indices of environmental quality, but so far there is little information on the extent to which production responses are mediated by genotypes. This study used a single source stock of blue mussels (Mytilus edulis) to explore differences between two bays. Test animals were held in suspension for 20 mo and growth and mortality observations of size-groups and of identified individuals were made at biweekly intervals. Average growth rates differed slightly between bays but mortality differences were marked and were the principle determinants of net production differences between the bays. Observed growth rates differed markedly between individuals but showed a striking consistency within individuals, indicative of genetic influence on this parameter. Because both mortality and growth interact with body size and season, it is clear that the estimated production levels and differences between bays would be influenced by the mixture of genotypes. We conclude that growth and mortality measures of M. edulis could provide sensitive environmental indices, but growth types in the test stock would need to be standardized. Key words: mussel; growth, mortality; environmental indices; genetic influence
Influence of Age, Condition, Sampling Time, and Method on Plasma Chemical Constituents in Free-Ranging Ringed Seals, Phoca hispida
Authors: Geraci J. R. , St. Aubin D. J. , Smith T. G.
Published: April 2011

Blood samples were obtained from 29 free-ranging ringed seals, Phoca hispida, on Herschel Island, Y.T.; 10 were shot and 19 were caught in nets. Age, condition, sampling time, and method had variable influence on plasma chemical constituents. Plasma sodium, chloride, and cholesterol levels in three seals judged to be in poor condition were lower than in the 26 remaining seals. Uric acid was highest in shot pups, but the dynamics of this nitrogenous metabolite in seals are obscure. Plasma levels of alkaline phosphatase, calcium, and cholesterol varied with age. Shot seals had higher plasma triglycerides and blood urea nitrogen (BUN), as a result of recent feeding. For reasons unknown, the circulating levels of two hepatocellular enzymes were elevated in all samples. Plasma from shot seals had falsely elevated potassium levels, due to the sampling technique. Glucose, bilirubin, inorganic phosphate, and aspartate aminotransferase were not significantly influenced by any of the variables studied. The plasma electrolytes and BUN in five captive ringed seals sampled over a 1-yr period correlated with levels in healthy, fasted free-ranging seals; uric acid levels were lower in the captive seals. Key words: phocid, ringed seals, plasma chemistry, hyponatremia, uric acid, enzymes
Bioeconomic Model of the Gulf of Carpentaria Prawn Fishery
Authors: Clark Colin W. , Kirkwood Geoffrey P.
Published: April 2011

We present a bioeconomic model, of an intermediate degree of complexity and realism, of the prawn fishery of the Gulf of Carpentaria and adjacent waters in Northern Australia. The model employs 21 parameters to describe the performance of two classes of vessels exploiting several stocks of prawns. The model predicts the number of vessels of each class entering the fishery under free access, and the prediction is compared with available data. The model is also used to obtain estimates for the economically optimal number of vessels of each type. Key words: model, economics of fisheries, limited entry, prawn fishery, Australia
Carcinonemertes errans and the Fouling and Mortality of Eggs of the Dungeness Crab, Cancer magister
Authors: Wickham D. E.
Published: April 2011

Laboratory experiments analyzing the correlation between epibiotic fouling and mortality of the eggs of the Dungeness crab, Cancer magister Dana, reveal that both can result from predation on crab eggs by the nemertean Carcinonemertes errans Wickham. Fouling appears to be stimulated by the release of yolk material into the egg clutch through worm feeding and defecation. Significant correlations exist between worm density and both fouling and mortality in field samples. The ranking of the correlations between these three parameters suggest that nemertean activity is the causative agent and that fouling is only incidentally correlated to egg mortality through its correlation to worm density. Key words: Carcinonemertes errans, Cancer magister, crab-egg fouling, crab-egg mortality
Bacterial Kidney Disease in Feral Populations of Brook Trout (Salvelinus fontinalis), Brown Trout (Salmo trutta), and Rainbow Trout (Salmo gairdneri)
Authors: Mitchum Douglas L. , Sherman Loris E. , Baxter George T.
Published: April 2011

Incidence and effects of bacterial kidney disease (BKD) were determined in wild, naturally reproducing populations of brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Salmo gairdneri) in a small lake and stream system in southeastern Wyoming, USA where BKD epizootics have been observed since 1972. During 1976, dead fish were collected at three upstream stations, and 60 live fish were collected from each of 11 stations. All fish were necropsied, and virological, bacteriological, and parasitological examinations were conducted by standard methods. An indirect fluorescent antibody technique was used to detect the BKD organism in cultures and kidney tissue smears. Bacterial kidney disease was diagnosed in 100% of the dead brook trout collected. Incidence among live fish ranged from 83% at an upstream station to only 3% at the most downstream location, and was highest in brook trout and lowest in rainbow trout. Two longnose suckers (Catostomus catostomus), the only non-salmonids collected, were found negative for BKD. Clinical signs of infection and the most severe infections were found only in brook trout. Five age-classes of feral brook trout were involved in the epizootics. Since other known pathogens were essentially absent, it is believed that all deaths were due to BKD. Relationships between species susceptibility to BKD, age-classes, water chemistry and water temperatures, and certain ecological conditions are discussed. Key words: bacterial kidney disease, feral trout, epizootics, brook trout, brown trout, rainbow trout
Chemical Modelling in Aqueous Systems. Speciation, Sorption, Solubility, and Kinetics.
Authors: Wegemann R.
Published: April 2011

not available
Sampling Emerging Chironomidae (Diptera) with Submerged Funnel Traps in a New Northern Canadian Reservoir, Southern Indian Lake, Manitoba
Authors: Rosenberg David M. , Wiens Allen P. , Bilyj Bohdan
Published: April 2011

We examined sampling characteristics of submerged funnel traps which were used to study emergence of Chironomidae in a large boreal riverine reservoir. Clay, bedrock, and marsh shorelines were sampled at 1.0-, 2.0-, 3.5-, and 4.5-m depths with four replicate traps at each depth. Numbers∙m−2 emerging from the three shorelines were similar but differences among depths were significant. The most common species emerging offshore (3.5 and 4.5 m) differed from those emerging inshore (1.0 and 2.0 m). Species emerging from all three shorelines were similar offshore. Inshore, clay and bedrock shorelines were similar but differed from the marsh shoreline. Twelve traps for each depth and 16 traps for each shoreline usually gave a ± 30% precision of the mean no.∙m−2 emerging. Single traps collected [Formula: see text] the number of species collected by 16 traps. All of the more abundant (≥ 1% of the total numbers caught) species in Southern Indian Lake were caught in two to four traps. A minimum of four traps was required to interpret emergence patterns of the most common species with one emergence peak; 16 for the most common species with two emergence peaks. Discontinuous trapping (48 h∙wk−1) gave similar results to continuous trapping (168 h∙wk−1). Our studies in Southern Indian Lake suggest that an optimal sampling strategy for mesotrophic lakes would be to trap discontinuously and use high numbers of traps.Key words: Chironomidae, sampling (biological), submerged funnel traps, reservoirs (water), trapping time, shorelines, depths, replicates, precision
Field Studies of DCMU-Enhanced Fluorescence as an Index of in situ Phytoplankton Photosynthetic Activity
Authors: Roy Suzanne , Legendre Louis
Published: April 2011

Comparison between the increase in fluorescence caused by DCMU (FD/FN: ratio of DCMU-enhanced to normal fluorescence) and the specific photosynthetic rate (P/B: photosynthetic activity per unit chlorophyll a) in the St. Lawrence Estuary showed that no overall correlation could be established between P/B and FD/FN, although there were significant correlations between these two variables on short transects. This reflected perhaps environmental and species composition changes. FD/FN vertical profiles in the Gulf of St. Lawrence and the Gulf of Guinea showed a characteristic increase with depth, as seen in laboratory cultures with a decrease in light intensity. This could be related to photosynthetic efficiency which is known to increase at lower light intensities. Technical problems involving the use of FD/FN as an estimator of P/B are also discussed. Further investigations are required before this fluorescence technique can be used regularly in field work to estimate photosynthetic activity.Key words: DCMU, fluorescence, photosynthesis, phytoplankton, St. Lawrence Estuary, Gulf of Guinea
Determination of Vancomycin in Lobster Meat
Authors: Herbst Doris V.
Published: April 2011

Residues of vancomycin in cooked lobster meat were detected by using a thin-layer chromatographic method with bioautography. Presumptive identification was provided by the Rf value coupled with the unique zone of inhibition, and residue levels of 5 μg/g could be detected. The procedure provides methodology needed for regulatory purposes.Key words: lobster meat, vancomycin, bioautography, thin-layer chromatography
Stock Assessment and Life History of a Newly Discovered Alaska Surf Clam (Spisula polynyma) Resource in the Southeastern Bering Sea
Authors: Hughes Steven E. , Bourne Neil
Published: April 2011

A 1977 exploratory survey of subtidal clam resources in the southeastern Bering Sea revealed extensive concentrations of Alaska surf clams (Spisula polynyma) along the north coast of the Alaska Peninsula. Using east coast hydraulic clam harvesters, subsequent 1977 and 1978 stock assessment surveys delineated a geographically isolated stock with an estimated exploitable biomass of 329 000 ± 52 000 t and conservatively calculated potential annual yield of 25 017 t (maximum sustainable yield) of whole clams. Production fishing trials at 13 sites in 1978 produced an average catch per unit effort of 815 kg/h with a 1.84-m-wide clam harvester.Life history studies indicated the species is long-lived (25 yr), slow growing (K = 0.135), fully recruited to the spawning population at 8 yr of age, subject to low natural mortality (conservatively calculated as M = 0.19), and attains maximum cohort biomass at ages between 9.4 and 13.0 yr. Biological rationale for management measures is presented.Key words: population assessment, sustained yield, surf clams, Alaska
A Procedure for Evaluating the Food Biomass Consumed by a Fish Population
Authors: Majkowski Jacek , Waiwood Kenneth G.
Published: April 2011

An application of the Ursin fish growth theory for evaluating the food biomass consumed by a fish population is proposed. In this procedure the total catabolism of a fish is treated as dependent on the level of available food. This is the major advantage of the procedure in comparison with that based on the most frequently used Winberg fish growth theory, in which the total catabolism rate is assumed to be independent of the available food level. The Atlantic cod (Gadus morhua) population inhabiting the southern Gulf of St. Lawrence (NAFO subarea 4T) in 1978 is considered in order to illustrate the procedure. The food biomass consumed by the cod population in this area and period is evaluated to be 0.727 million tonnes (the food consumption of the 0th cod age-group is not included). The uncertainty in the estimate of this food biomass due to uncertainties in the input parameters for the procedure is estimated to be in the range of 20% (standard error). Possible ways of improving the results of the procedure are discussed in the light of uncertainties in the input parameters and the sensitivity of the model upon them. It is concluded on the basis of a sensitivity analysis performed for the numerical example of procedure and the foraging theory for fish that the assumption introduced by Winberg can, in certain cases, introduce considerable bias to the procedure results.Key words: fish, food consumption, growth, physiology, bioenergetics, cod, model, sensitivity analysis
Orthophosphate and its Flux in Lake Waters
Authors: White E. , Payne G. , Pickmere S. , Pick F. R.
Published: April 2011

Molybdate reactive high molecular weight (MW > 5000) phosphorus (RHMW-P) in solution was separated from low molecular weight material (PO4-P) by Sephadex gel (G25–150). PO4-P is as close to orthophosphate as has been possible to achieve with molybdenum blue technology. Chromatograms of near-surface waters of 32 lakes showed that RHMW-P was rarely the dominant component of dissolved reactive phosphorus (DRP), and so cannot be the major influence causing discrepant estimates of orthophosphate concentrations derived from molybdenum blue and radiotracer technology. The low molecular weight material (PO4-P) may still contain chemically reactive organic phosphorus which could lead to overestimation of orthophosphate. Recent literature points to discrepancies in radiotracer estimates too, so further effort is required to provide reliable assessment of orthophosphate in lake water. Estimates of orthophosphate flux from solution to particulate material based on 32PO4-derived turnover times are likely to be in error irrespective of the source of orthophosphate estimate.Key words: molybdenum blue method, radiotracer, orthophosphate flux, reactive high molecular weight phosphorus, gel chromatography, radiobioassay