bluuebunny/crossref_metadata_2025 huggingface dataset:
A Computer Simulation of the Effects of Superimposed Mortality Due to Pollutants on Populations of Fathead Minnows (Pimephales promelas)
Authors: Waller William T. , Sparks Richard E. , Cairns Jr. John , Dahlberg M. L.
Published: April 2011

This computer simulation study tested the effects of 99 levels of proportional mortality on fathead minnow (Pimephales promelas) populations, assuming that the parent–progeny relationship is of the form proposed by Ricker. Limited data from two studies on three lakes were available to fit the model and obtain estimates of parameters for fathead minnow populations. Based on these estimates, 25 replications of a 50-generation cycle were simulated under two levels of environmental variability. Arbitrary extinction levels of 5, 100, and 500 females had little effect on the results. Increasing environmental variation lowered the percentage mortality at which population extinctions occurred. In general, the results are compatible with the recommendation of the U.S. Committee on Water Quality Criteria, that the maximum concentration of zinc to which fish could be continuously exposed should not exceed [Formula: see text] the 96-hr TLm (median tolerance limit) — a concentration that caused a 50% reduction in the mean number of eggs laid per female by fathead minnows in a laboratory study.
Chronic Effects of Low Dissolved Oxygen Concentrations on the Fathead Minnow (Pimephales promelas)
Authors: Brungs William A.
Published: April 2011

Fathead minnows were exposed to constant dissolved oxygen concentrations (1.0–5.0 mg/liter) for 11 months. The number of eggs produced per female was reduced at 2.0 mg/liter; no spawning occurred at 1.0 mg/liter. Fry growth was reduced significantly at all concentrations below the control (7.9 mg/liter). Fry survival was reduced at 4.0 mg/liter and lower dissolved oxygen concentrations; 18% of the survivors at 4.0 mg/liter were deformed. The time required for hatching was increased at successively lower oxygen concentrations by as much as 50% (from 5.0 under control conditions to 7.8 days at 2.0 mg/liter), but no effect on percentage hatch was observed.
Migrations of Adult and Juvenile Walleyes (Stizostedion vitreum vitreum) in Southern Lake Huron, Lake St. Clair, Lake Erie, and Connecting Waters
Authors: Ferguson R. G. , Derksen A. J.
Published: April 2011

Recoveries of walleyes (Stizostedion vitreum vitreum) tagged as adults and juveniles at various sites in waters from southern Lake Huron to eastern Lake Erie provided information on the migrations of the Thames River stock and the mixing of these fish with other stocks in the study area. Walleyes spawning in the Thames River in March and April quickly migrated into the St. Clair River and southern Lake Huron, where they mingled with other stocks, including some from Lake Erie. The return migration to the Thames River occurred between November and March. Juvenile walleyes tagged in Lake St. Clair, on the other hand, moved downriver to Lake Erie. Young-of-the-year fish tagged in western Lake Erie, many presumably of Lake St. Clair origin, provided evidence of a reverse migration, since they tended to move back into Lake St. Clair and Lake Huron as they matured. Adult walleyes tagged along the Canadian shore of Lake Erie migrated eastward during the summer, but were recovered in or near the western basin during the spawning season. Thus, western Lake Erie appeared as a juvenile milling or mixing area during the summer, whereas southern Lake Huron and the north shore of central and eastern Lake Erie were adult areas.
Net Avoidance Behavior in American Shad (Alosa sapidissima) as Observed by Ultrasonic Tracking Techniques
Authors: Leggett William C. , Jones Robert A.
Published: April 2011

During tracking of 13 adult American shad (Alosa sapidissima) with ultrasonic transmitters in 49 approaches to commercial drift gillnets in the lower Connecticut River, only one shad was captured. Typically, shad moved to within 1–2 m of the net before sensing its presence, then turned and swam along the net, close to the mesh, to its end, where they turned and continued their upriver migration. Sight appeared to play an important role in net detection. However, 14 avoidances were observed when light intensities were inadequate to allow visual detection of the mesh. It was concluded that other senses, perhaps the lateral line, also function in net avoidance, especially when sight is impaired.
Levels of Constituents of Glycoproteins in the Sera of Pacific Salmon
Authors: Qureshi M. D. , Hledin R. V. , Anastassiadis P. A. , Vanstone W. E.
Published: April 2011

The levels of hexosamine, sialic acid, fucose, and protein in serum of sockeye salmon (Oncorhynchus nerka) and, to a limited extent, in sera of coho salmon (O. kisutch) and chinook salmon (O. tshawytscha) at two reproductive stages, were determined. Hexosamine, sialic acid, fucose, hexose, seromucoid, and protein content of sexually maturing (early) and mature (spawning) sockeye salmon were studied and a comparison was attempted with the corresponding composition of bovine serum. Content of the above serum constituents was lower in spawning than in maturing populations. Protein content was much less, hexosamine a little less, and sialic acid higher, in the sera of sockeye salmon than in bovine serum. The protein–carbohydrate complex of serum appeared to contain more hexosamine and much more sialic acid than the protein–carbohydrate complex of bovine serum. Furthermore, the sialic acid-to-hexosamine ratio was much higher in sera of salmon than in bovine serum. Some other sex and reproductive stage differences were detected and reported.
Growth and Fecundity of Rainbow Trout (Salmo gairdneri) Exposed to Single Sublethal Doses of X-rays During the Eyed Embryo Stage
Authors: Welander Arthur D. , Wadley Gerald W. , Dysart Douglas K.
Published: April 2011

When rainbow trout (Salmo gairdneri) were reared for 2 years after irradiation with 21, 83, and 203 roentgens (R) during the eyed stage, the irradiation had no demonstrable effect on survival, growth, or fecundity. The trout were reared at temperatures of 15.4 and 17.2 C in parallel experiments for 160 days after fertilization. At the end of 2 years, 65 female trout (and 56 males), averaging more than 1400 g in weight, produced 186,400 eggs. Egg production was not related to irradiation dose or temperature; however, there was a slight dose-related increase in number surviving to the eyed stage in most of the irradiated groups.
Bacterial Counts of Commercial Fish Diets
Authors: Trust T. J.
Published: April 2011

Two diets formulated and offered for commercial fish production were examined to determine their microbial burden. The total count of aerobic bacteria ranged from 103 to 107 bacteria per gram of diet. The diets contained psychrophilic and thermophilic species and up to 104 aerobic and anaerobic spore-forming bacteria per gram. Enterococci and members of the Enterobacteriaceae, including species of Salmonella, were also present. Fluorescent pseudomonads were detected in 18 of the 47 samples tested, Proteolytic, amylolytic, lipolytic, and haemolytic organisms were shown to be present in measurable numbers. The total viable aerobic count did not change markedly on storage of representative samples at 4, 20, or 30 C.
Two Simple Durable Epifaunal Collectors
Authors: Bourget Edwin , Lacroix Guy
Published: April 2011

Vertical and horizontal epifaunal collectors, especially for the infralittoral zone, are described. Special attention is given to stability of the collectors and to easy recovery and replacement of the test panels. The collectors were used under severe environmental conditions and were found very satisfactory. Species collected by the two collectors differed greatly. The vertical collector yielded the greater variety of species, and the horizontal collector the greater number of specimens.
Advantages and Limitations of "Simple" Fishery Models in Light of Laboratory Experiments
Authors: Silliman R. P.
Published: April 2011

"Simple" fishery models as treated herein are those requiring only catch and effort data for fitting. In the models described, the yield-on-biomass curve is considered equivalent to the growth curve of the population: Schaefer, logistic; Fox, Gompertz; Pella and Tomlinson, generalized. The Fox model is more realistic for fish populations than the Schaefer, eliminating the constraint of a symmetrical yield curve. The Pella–Tomlinson model is general, including the others as special instances. Tests against data from laboratory populations of guppies support the validity of the Fox and Pella–Tomlinson models. The Fox model is the simpler to fit of the two (as it has less parameters) and has been shown to be appropriate for a number of commercial fisheries. Advantages of the models include their minimal requirements for basic data and relative ease of fitting. Limitations include lack of provision for reproductive lag and waste of biological information other than catch and effort.
Cadmium Poisoning in Fundulus heteroclitus (Pisces: Cyprinodontidae) and other Marine Organisms
Authors: Eisler Ronald
Published: April 2011

In acute toxicity bioassays with [Formula: see text] at 20 C and 20‰ salinity, the concentrations fatal to 50% of the organisms of various marine species in 96 hr ranged between 0.32 and 55.0 mg/liter Cd2+. The order of sensitivity was: sand shrimp, Crangon septemspinosa (0.32); hermit crab, Pagurus longicarpus (0.32); grass shrimp, Palaemonetes vulgaris (0.42); common starfish, Asterias forbesi (0.82); common soft-shell clam, Mya arenaria (2.2); green crab, Carcinus maenus (4.1); Atlantic oyster drill, Urosalpinx cinerea (6.6); eastern mud snail, Nassarius obsoletus (10.5); sandworm, Nereis virens (11.0); striped killifish, Fundulus majalis (21.0); blue mussel, Mytilus edulis (25.0); sheepshead minnow, Cyprinodon variegatus (50.0); and mummichog, Fundulus heteroclitus (55.0). Mummichogs were more susceptible to cadmium exposures at 20 C than at 5 C and at 5‰ salinity than at 15, 25, or 35‰. Additional studies with mummichogs clearly demonstrated that 96 hr was not sufficient to adequately evaluate cadmium toxicity to this species. Mummichog whole body cadmium residues determined by atomic absorption provided a useful index of cadmium body burden among fish surviving exposure. However, cadmium residue data from dead mummichogs were of limited worth owing to accumulation after death.
An Experiment with Medaka, Oryzias latipes, and a Critique of the Hypothesis that Teleost Egg Size Controls Vertebral Count
Authors: Lindsey C. C. , Ali M. Y.
Published: April 2011

In each of two sets of experiments, two female medaka, Oryzias latipes, that laid different-size eggs were crossed reciprocally with two males. Vertebral counts of the offspring differed significantly between batches, but there was no consistent correlation between egg size and vertebral count. Both the highest and lowest counts resulted from crosses with females laying large eggs. Other experiments are reviewed, and it is concluded that within the same race of fish there is no causal connection between vertebral number and egg size, although between different races or related species large adult size is often correlated with high vertebral count. The possible advantages of variation in vertebral number are discussed.
Methylmercury in Freshwater and Marine Fishes in New Brunswick, in the Bay of Fundy, and on the Nova Scotia Banks
Authors: Zitko V. , Finlayson B. J. , Wildish D. J. , Anderson J. M. , Kohler A. C.
Published: April 2011

American eel (Anguilla rostrata), chain pickerel (Esox niger), white perch (Morone americana), yellow perch (Perca flavescens), brook trout (Salvelinus fontinalis), and Atlantic salmon (Salmo salar) contained 0.07–2.08, 0.27–1.58, 0.75–1.07, 0.20–1.05, 0.08–0.13, and 0.09 ppm of methylmercury, expressed as mercury on wet weight basis, respectively. With only two exceptions, levels of methylmercury in marine fish were below 0.13 ppm. Some of the freshwater sampling locations could be directly associated with an industrial activity in the area, whereas others suggested pollution by airborne mercury. However, the concentration of methylmercury in eels from a lake in New Brunswick did not change over a period of 46 years, indicating that elevated levels of mercury may in some instances reflect the natural situation.
Some Relations Between Zooplankton and Bunker C Oil in Chedabucto Bay Following the Wreck of the Tanker Arrow
Authors: Conover R. J.
Published: April 2011

Zooplankton ingested small particles of oil that were found dispersed throughout the water column in Chedabucto Bay following the wreck of the tanker Arrow. As much as 10% of the bunker C in the water column was associated with zooplankton and their feces contained up to 7% bunker C. The oil had no apparent effect on the organisms. In addition to the particulate oil which was exported from the bay by hydrodynamic processes, perhaps 20% more was sedimented to the bottom as zooplankton feces.
Increased Predation by the Torrent Sculpin, Cottus rhotheus, on Coho Salmon Fry, Oncorhynchus kisutch, During Moonlight Nights
Authors: Patten Benjamin G.
Published: April 2011

In stream aquaria, the percentages of coho salmon fry removed by the torrent sculpin averaged 70 in four tests on moonlight nights and 24 in seven tests on dark nights.
Publications by Edith and/or Cyril Berkeley
Authors: Arai Mary Needler
Published: April 2011

The publications of Edith and Cyril Berkeley are listed, those on their research on Polychaeta being of special interest.
Polychaetes as Intermediate Hosts of Helminth Parasites of Vertebrates: A Review
Authors: Margolis L.
Published: April 2011

The role of polychaetes as intermediate hosts of helminth parasites of aquatic vertebrates is reviewed. Some 18–20 species of trematodes and three or four each of cestodes and nematodes are known to have larval stages in these annelids. There are no records of acanthocephalan larvae from polychaetes. Trematoda use polychaetes as first (three species) or second intermediate hosts. The polychaete hosts are found among various genera of Errantia, Sedentaria, and Myzostomida. Definitive hosts are mainly fishes, with a few species of trematodes and one of cestodes developing in birds, and apparently one genus of nematodes (two species) maturing in the lungs of seals. A list of polychaetes and their larval helminth parasites is given.
Dodecaceria berkeleyi n.sp., a Polychaete (Family Cirrutulidae) from New Zealand
Authors: Knox G. A.
Published: April 2011

The described species of the genus Dodecaceria are reviewed. Fourteen species are recognized and their diagnostic characters are given. A new species, Dodecaceria berkeleyi, is described from New Zealand where it is found boring in the shells of large gastropod molluscs. An outline is given of the nature of the skin pigments, which are similar to the arenicolochrome of lugworms. Asexual reproduction in the genus is reviewed, and an account is given of autotomy in D. berkeleyi, followed by regeneration to give rise to two individuals, a method of reproduction similar to that which occurs in the colonial tube builder Dodecaceria fistulicola. An advanced larval stage found in the burrows of D. berkeleyi is described.
Simulation Studies of the Adams River Sockeye Salmon (Oncorhynchus nerka)
Authors: Larkin P. A.
Published: April 2011

The pattern of abundance of sockeye salmon (Oncorhynchus nerka) of the Adams River since 1938 is: 1 year large or "dominant," 1 year small or "subdominant," and 2 years very small or "off." In recent years, the subdominant run has shown indications of becoming as large as the dominant. This pattern can be accounted for by a model system in which predation is not sufficient to influence the dominant run, but predators, benefited by the abundance of prey, remove such a large fraction in the 3 succeeding years that the pattern is retained. Buffering of predation by the dominant run accounts for the larger size of the subdominant. Patterns similar in form to those observed naturally since 1922 are produced over a narrow range of parameters, and suggest that the particular circumstances of the Adams run are necessary to the nature of the population fluctuation, but are not so particular that some other pattern could not have emerged with a different sequence of environmental conditions. Taking an array of results of a series of simulations suggests that the odds of developing the existing pattern were about 50:50, although the subdominant run would more commonly become dominant as well by 1951, rather than as late as the 1960's. The double dominance situation is stable in the model system. In the present circumstances it seems appropriate to explore the possible benefits of managing the fishery so as to enhance the growth in size of the subdominant run, and perhaps to consider predator-removal programs to enable development of large runs on all 4 years of the traditional cycle.
Radioisotope X-Ray Fluorescence Spectrometry in Aquatic Biology: A Review
Authors: Calaprice J. R. , McSheffrey H. M. , Lapi L. A.
Published: April 2011

X-ray fluorescence spectrometry is described as an efficient means of carrying out non-destructive qualitative and quantitative chemical analyses of inorganic substances. A brief review is presented on the way in which this methodology was developed to recognize marked individuals and its application towards determining the geographic origin of organisms using multivariate analysis of the trace element composition of untagged animals. In addition, the results of experiments in which 34 species of invertebrates were compared and different parts of the same organisms irradiated, demonstrated that organisms may possess characteristic elemental compositions that are species specific. Multiple discriminant function analysis of the data showed that species may be classified on the basis of their chemical composition with few errors. Winter and summer growth of molluscan shells were distinguishable by the same method of elemental analysis, and a method for determining the age of organisms is given. Stepwise discriminant function analysis of the groups of elemental standards demonstrate that it is possible to isolate the most significant differences found between the groups compared by this methodology. The importance of these findings to studies in biogeochemistry, physiology, and pollution are briefly reviewed. X-ray fluorescence spectrometry is considered to be one of a number of related forms of data acquisition systems, each with broad applications.
An Aberrant Strain of the Bacterial Fish Pathogen Aeromonas salmonicida Isolated from a Marine Host, the Sablefish (Anoplopoma fimbria), and from Two Species of Cultured Pacific Salmon
Authors: Evelyn T. P. T.
Published: April 2011

Biochemically unique strains of the causative bacterium (Aeromonas salmonicida) of furunculosis in fish are described. The strains were first isolated from a marine host, the sablefish, Anoplopoma fimbria, and later, from sockeye (Oncorhynchus nerka) and chum (Oncorhynchus keta) salmon. The strains were essentially identical, and although always isolated from diseased fish cultured in sea or brackish water, they behaved like typical freshwater bacteria.The outbreaks of furunculosis in local fish-culture facilities were rare events that are thought to have resulted from import of the pathogen in wild carrier fish. In the case of the sablefish that was captured at sea shortly before its death, the infection appears to represent the first instance of spontaneous furunculosis in a marine fish.
Derzhavin's Biostatistical Method of Population Analysis
Authors: Ricker W. E.
Published: April 2011

Derzhavin's biostatistical method, as modified by Boiko and others, uses annual age censuses and catch statistics to compute the utilized stock (virtual population), Vi, of year-class i in a given year as the sum of all members of that year-class that are caught in the current and future years. The sum of Vi values for all year-classes present in a given year is the total utilized population, V. The biostatistical rate of exploitation for individual ages (Ci/Vi), or for the stock as a whole (C/V), is the catch divided by the utilized stock. If ages of the fish in the stock are read too low, values of Ci/Vi and C/V are too large. For fully recruited fish, Ci/Vi is an unbiased estimate of the total mortality rate, A, bat for incompletely recruited ages, it differs progressively from A and has no simple interpretation. Variations in abundance of successive year-classes do not affect the interpretation of Ci/Vi or C/V for fully recruited ages, but changes in rate of fishing, F, are disturbing. When incompletely recruited ages are included in a biostatistical computation (as has usually been done), C/V does not have any precise interpretation in terms of population parameters. In addition, variations in year-class strength affect the value of C/V even when F does not change from year to year. It is possible to use C/V for the whole catch as an "arbitrary" index that reflects the direction and magnitude of changes in intensity of fishing over a period of years. However, even for this purpose the same minimum age must be used in all years. When data for a long series of years are available, the utilized year-class strength (ΣCi) of the year-class hatched in year i can be compared with the total utilized stock (or the utilized mature stock) present in year i, in order to examine parent–progeny relations. Incompletely recruited as well as fully recruited ages can be used in this comparison, but adjustments are necessary if mortality rate (natural or fishing) changes from year to year. The biostatistical method does not provide separate estimates of natural and fishing mortality rates. If the possibility of a moderate or large natural mortality is disregarded, serious errors of interpretation may result.
Ambicoloration in a Petrale Sole (Eopsetta jordani)
Authors: Forrester C. R. , Smith M. S.
Published: April 2011

Ambicoloration, which was complete except for a small unpigmented area on the blind side of the head and a portion of the pectoral fin, was noted in a petrale sole (Eopsetta jordani) taken off the west coast of Vancouver Island, B.C. The specimen also showed anomalous development of the dorsal fin and had two fused vertebrae near the caudal peduncle.
An Evaluation of Two Tags with Northern Pike (Esox lucius)
Authors: Koshinsky Gordon D.
Published: April 2011

In a 4-year study of northern pike (Esox lucius) at Lac la Ronge, Sask., barb-anchored spaghetti dart tags (when applied with special needles and disinfectant) were retained longer than monofilament-attached preopercular disc tags. Losses after 2 years were 13 and 92%, respectively. Tagging mortality tended to be higher among dart-tagged individuals, but was only 12% after 2 years. Condition tended to be depressed by both tags and, among females, more so by the preopercular discs. Growth increments tended to be smaller for disc-tagged than for dart-tagged individuals of the same sex. Disc-tagged pike also dispersed more widely and were more vulnerable to angling. It is suggested that a brightly colored tag attached to the head of a predatory species, such as pike, interferes with feeding, perhaps by startling prey; such interference would explain all of the comparative tagging effects observed.
Croissance en longueur et en poids des perchaudes Perca flavescens de la Grande Anse de l'île Perrot au lac Saint-Louis
Authors: Fortin Réjean , Magnin Etienne
Published: April 2011

In this study, growth in length is based upon age determination on the opercular bones of 2170 specimens, collected throughout the year from June 1967 to October 1969. The opercular bone shows allometric growth and this is taken into account in back calculations. Grande Anse perch show comparatively rapid growth. Growth of males is slower than that of females. Seasonal growth extends from May to September. Faster growing fish reach sexual maturity earlier in life. Length–weight relationship exponent is 3.107. Due to the weight of the gonads, female perch show maximum condition index values in winter.
The Bacterial Population in Vertical Flow Tray Hatcheries During Incubation of Salmonid Eggs
Authors: Trust T. J.
Published: April 2011

During the incubation period, the number of bacteria on the surface of salmonid eggs in vertical tray hatchery stacks varied between 4.8 × 103 and 107 aerobic organisms per square centimeter of egg surface. The bacterial count in the tray water varied between 1.1 × 103 and 5.4 × 103 organisms per milliliter. The most common isolates from the eggs were species of Cytophaga and Pseudomonas. Aeromonas hydrophila was also isolated. These species remained on the eggs throughout incubation, and were also isolated from tray surfaces and tray water.
Growth of Larval Herring (Clupea harengus) in the Bay of Fundy and Gulf of Maine area
Authors: Das Naresh
Published: April 2011

Initial growth rate for autumn-hatched herring larvae in the Bay of Fundy–Gulf of Maine area is about 2 mm per week. It gradually declines to less than 1 mm per week during the late autumn and winter months, and then increases geometrically in the spring and early summer to an average of 2.5 mm per week.
Effects of Long-Term Exposure to Carbaryl (Sevin) on Survival, Growth, and Reproduction of the Fathead Minnow (Pimephales promelas)
Authors: Carlson A. R.
Published: April 2011

When fathead minnows (Pimephales promelas) were exposed to five concentrations (0.008–0.68 mg/liter) of the insecticide carbaryl for 9 months and throughout a life cycle, the highest concentration prevented reproduction and decreased survival. At the high concentration, testes contained motile sperm and ovaries were in a flaccid condition and appeared to be in a resorptive state. At the 0.68 mg/liter concentration, carbaryl appeared to contribute to mortality of larvae (produced by unexposed parents) within 30 days of hatching. Survival of young grown in the 0.008 mg/liter concentration was reduced. Since no demonstrable effects were noted for survival, growth, or reproduction at the 0.017, 0.062, and 0.21 mg/liter concentrations, this low survival value is considered not due to carbaryl. The 96-hr median tolerance concentration (TL 50) and the lethal threshold concentration (LTC) for 2-month-old fathead minnows were 9.0 mg/liter. The maximum acceptable toxicant concentration (MATC) for fathead minnows exposed to carbaryl in water with a hardness of 45.2 mg/liter and a pH of 7.5 lies between 0.21 and 0.68 mg/liter. The application factors (MATC/96-hr TL50 and MATC/LTC) both lie between 0.023 and 0.075.
Winter Geostrophic Circulation in the Gulf of St. Lawrence
Authors: El-Sabh M. I. , Johannessen O. M.
Published: April 2011

The field of winter geostrophic circulation at the surface of the Gulf of St. Lawrence has been calculated for the first time. The dynamic method has been applied with Defant's method used for determining a variable reference layer. The main features of the reference layer are the three depressions, west and southeast of Anticosti Island and at the middle of Cabot Strait. The existence of two gyres (anticlockwise west and clockwise southeast of Anticosti Island), the outflow on both sides of Cabot Strait, and inflow at the middle of it are the dominant features in the winter surface circulation. A net volume transport through Cabot Strait in February 1962 was found after adjustment for zero salt transport, to be 6 × 103 m3/sec in the outward direction.
Effects of Temperature on Growth and Survival of Young Brook Trout, Salvelinus fontinalis
Authors: McCormick J. Howard , Hokanson Kenneth E. F. , Jones Bernard R.
Published: April 2011

Instantaneous rates of growth, mortality, and net biomass gain were determined for alevin through juvenile brook trout reared for 8 weeks at six constant temperatures: 7.1, 9.8, 12.4, 15.4, 17.9, and 19.5 C. Growth rates were maximum between 12.4 and 15.4 C. Mortality rates increased between 15.4 and 17.9 C and were maximum between 17.9 and 19.5 C. The net rates of biomass gain were maximum between 12.4 and 15.4 C.Median upper thermal tolerance limits (TL50 values) were determined for newly hatched and swim-up alevins. Tolerance did not increase in newly hatched alevins with acclimation to temperatures from 2.5 to 12 C. The upper 7-day TL50 for newly hatched alevins acclimated over this range of temperatures was 20.1 C. The swim-up alevins showed both an increase in temperature tolerance with acclimation temperatures between 7.5 and 12 C and an increase in tolerance over that of the newly hatched alevins at comparable acclimation temperatures. The ultimate 7-day TL50 of swim-up alevins was 24.5 C. Swim-up alevins exceed newly hatched alevins in thermal tolerance by 2.0–4.5 C, depending on the temperature of acclimation. The TL50 of newly hatched alevins of comparable acclimation (12 C) is reduced by about 2 C when the exposure time is increased from 1 to 7 days.
Acidification of the La Cloche Mountain Lakes, Ontario, and Resulting Fish Mortalities
Authors: Beamish Richard J. , Harvey Harold H.
Published: April 2011

The loss of populations of lake trout (Salvelinus namaycush), lake herring (Coregonus artedii), white suckers (Catostomus commersoni), and other fishes in Lumsden Lake was attributed to increasing levels of acidity within the lake. An absence of fishes was also observed in nearby lakes. In some lakes, acid levels have increased more than one hundredfold in the last decade. The increases in acidity appear to result from acid fallout in rain and snow. The largest single source of this acid was considered to be the sulfur dioxide emitted by the metal smelters of Sudbury, Ont.In 1971, pH measurements were taken from 150 lakes in the general study area 65 km southwest of Sudbury. Some 33 of these lakes showed a pH of less than 4.5 and were described as "critically acidic." An additional 37 lakes had a pH in the range of 4.5–5.5 and were termed "endangered" lakes.
Swimbladder Morphology and Specific Gravity of Myctophids off Oregon
Authors: Butler John L. , Pearcy William G.
Published: April 2011

Three general types of swimbladders were found in the eight species of myctophids studied: gas-filled, fat-invested, and atrophied or reduced. Small specimens of all species had thin-walled, gas-filled swimbladders. Large specimens of Stenobrachius leucopsarus had fat-invested swim-bladders and large Diaphus theta had either gas-filled or atrophied swimbladders, as found by other workers. Large Tarletonbeania crenularis had either gas-filled or reduced swimbladders, large Lampanyctus ritteri and L. regalis had reduced swimbladders, and large Stenobrachius nannochir had fat-invested swimbladders. Protomyctophum thompsoni and P. crockeri retained gas-filled swimbladders.High body lipid content was found in S. leucopsarus, S. nannochir, L. ritteri and D. theta, and low lipid content was found in the other four species. Myctophids with high lipid content had specific gravities close to that of sea water (1.026–1.030). Tarletonbeania crenularis with a reduced swimbladder had a specific gravity of 1.088. Lampanyctus regalis had a lower specific gravity (1.040) due to high water content of the tissue.The swimbladder to body volumes in S. leucopsarus and D. theta were inversely related to body size and lipid content, indicating that lipids assume the primary buoyancy function as the gas-filled swimbladder regresses with age. This change may eliminate the physiological constraints imposed by a gas-filled swimbladder and permit the more extensive diel vertical migrations of adults.
A Quantitative Evaluation of Survival to the Adult Stage and Other Characteristics of Pink Salmon (Oncorhynchus gorbuscha) Produced by a Revised Hatchery Method Which Simulates Optimal Natural Conditions
Authors: Bams R. A.
Published: April 2011

To evaluate a hatchery method utilizing a gravel medium and filtered water during incubation, comparisons were made between naturally and artificially propagated parts of one native stock of pink salmon (Oncorhynchus gorbuscha) of the Tsolum River, B.C. Yolk utilization (growth rate) of fry was unimpeded in the hatchery environment, but hatchery fry migrated about 6 days earlier than creek fry. Hatchery survival was about six times that in the creek. The main test criterion — relative survival to the adult stage of fish from both treatments following migration from the creek — was tested by release of two similar groups of fry identified by a double finclip and recovery of marked adults upon return. Both groups survived at virtually the same rate. Numbers of actual mark recoveries were adequate to demonstrate statistically that survival of hatchery fish following release was not less than 90% of creek fry survival and that the final gain ratio of the hatchery treatment was not less than 5.44 (P <.005). Adult size, sex ratio, fecundity, and timing were not adversely affected by the hatchery treatment.
Conversion, Maintenance, and Assimilation for Walleye, Stizostedion vitreum vitreum, as Affected by Size, Diet, and Temperature
Authors: Kelso John R. M.
Published: April 2011

An optimum ration was not readily apparent as conversion differed only slightly at high and low rations. Gross (K1) and net (K2) conversion was affected by neither ration size nor temperature, but decreased with increasing fish size. Conversion of the third order (K3) was affected only by temperature, being greater at higher temperatures. Gross and net conversion were consistently lower at cycled temperatures, 16–8 C. Gross and net conversion were similar since the high assimilation efficiency (82.1–97.9%) of walleye (Stizostedion vitreum vitreum) did not greatly alter the latter.Assimilation efficiency was dependent upon diet type, least for invertebrates (82.1% for amphipods and 83.5% for crayfish) and greatest for fish (96.9% for age O perch and 97.9% for emerald shiners). Assimilation efficiency decreased with increasing walleye size (slope of − 0.0045) irrespective of the food organism. Regurgitation of crayfish occurred in two of three trials, and it was not established if this was a natural phenomenon.Maintenance requirement per gram was independent of fish size, but was affected by temperature. Maintenance between temperatures of 4–12 C was similar, 33.3–45.7 cal/g walleye per week, but increased greatly above 12 C. Results from maintenance experiments paralleled Winberg's (1956) approximation of routine metabolism.
Predation by Rainbow Trout (Salmo gairdneri): the Influence of Hunger, Prey Density, and Prey Size
Authors: Ware D. M.
Published: April 2011

The feeding behavior of rainbow trout (Salmo gairdneri) was investigated by exposing fish to several densities and sizes of prey over a range of four substrates of varying complexity. Within substrate treatments the rate of predation could be stimulated by increasing either prey density, prey size, or predator hunger. Between treatments, however, both the intensity of predation and total food consumption proved to be inversely related to the complexity of the substrate because a number of prey were able to find cover and thus escape detection.The results further indicate that the nature of foraging behavior may be controlled by a critical rate of food capture. If trout did not exceed an average of.058 captures sec,−1 substrate-oriented search proceeded to wane.
Biodegradation of Trisodium Nitrilotriacetate in a Model Aerated Sewage Lagoon
Authors: Rudd J. W. M. , Hamilton R. D.
Published: April 2011

The effect of temperature on the biodegradation of trisodium nitrilotriacetate (Na3NTA) in a model aerated sewage lagoon was investigated. The percent breakdown of incoming NA3NTA at 15, 5, and 0.5 C was 93, 47, and 22% respectively. On the basis of these results, it can be expected that aerated sewage lagoons operating in the "mid-continental" climate of the Canadian prairie provinces would discharge at least 50% of incoming Na3NTA for 6 months of the year.The presence of a bacterial predator, Daphnia, was found to enhance the breakdown of Na3NTA.Fluctuations in Na3NTA removal appeared to increase with decreasing model lagoon temperature.
Gonad Maturation of Brook Trout (Salvelinus fontinalis) in a High Mountain Lake Under a Modified Photoperiod
Authors: Larson Gary Lee
Published: April 2011

Gonad maturation of brook trout (Salvelinus fontinalis) in Pratt Lake appeared similar to those reported for other areas although the day-length cycle was greatly modified by snow cover that capped the lake until early summer.
Pectoral Fin Length in the Dogfish Squalus acanthias off British Columbia
Authors: Forrester C. R.
Published: April 2011

In Squalus acanthias from three localities in British Columbia, mean lengths of the pectoral fin ranged from 85 to 93% of the nares–last gill slit length as compared to 76 and 106% for short-finned and long-finned forms of the species described in the literature.
Predation on Harbour Porpoise, Phocoena phocoena, by a White Shark, Carcharodon carcharias
Authors: Arnold P. W.
Published: April 2011

A specimen of the white shark, Carcharodon carcharias, brought into Leonardville, Deer Island, N.B., on August 13, 1971, contained three harbour porpoises, Phocoena phocoena, in variable states of digestion. This record on predation is discussed in conjunction with literature reports of a similar nature and one other previously unpublished observation.
Correction for Lag in Continuous-Flow Respirometry
Authors: Evans David O.
Published: April 2011

The lag and damping effect caused by fluctuations in the oxygen content of the respiration chamber in continuous-flow respirometry can be eliminated by addition of the simple correction factor (chamber volume × initial – final outflow oxygen concentration) to the ordinarily used formula (flow × mean difference between inflow and outflow oxygen concentration). Metabolism data for six rainbow trout, Salmo gairdneri, are presented.
Downstream Migration of Recently Transformed Sea Lampreys Before and After Treatment of a Lake Michigan Tributary with a Lampricide
Authors: Hodges John W.
Published: April 2011

After the Pere Marquette River was treated with a lampricide in May 1964, the number of recently transformed sea lampreys (Petromyzon marinus) collected in the water-intake structure of a chemical plant near the mouth of the stream dropped 99.5%, from 13,913 (average for 1962–63 and 1963–64) to 76 (average for the next four migration seasons). Average length of the lampreys caught increased markedly after the treatment. In five of the six migration seasons, the catch of downstream migrants was higher in the fall than in the spring.
Acute Toxicity of Yellow Phosphorus to Atlantic Cod (Gadus morhua) and Atlantic Salmon (Salmo salar) Smolts
Authors: Fletcher G. L. , Hoyle R. J.
Published: April 2011

The acute toxicity of yellow phosphorus (P4) to Atlantic cod (Gadus morhua) and Atlantic salmon smolts (Salmo salar) was investigated using two experimental procedures: (a) continuous exposure and (b) single brief exposure.In continuous-exposure experiments, P4 was lethal to cod and seawater-maintained salmon at concentrations as low as 1.89 and 0.79 μg/liter, respectively. Salmon that were exposed to P4 concentrations of 40 μg/liter or less developed a distinct external red color and showed signs of extensive hemolysis. At death, salmon that had been exposed to P4 concentrations of 90 μg/liter and lower showed a progressive decline in hematocrits. In contrast, cod were never observed to show any evidence of external redness, hemolysis, or reduced hematocrits.In the brief-exposure experiments, cod and salmon were subjected (20 min to 3.5 hr) to P4 concentrations ranging from 245 to 4030 μg/liter. These brief exposures resulted in mortalities to both species that were delayed for as long as 2 weeks. Salmon turned "red" 16–24 hr following exposure, and at death showed evidence of hemolysis and reduced hematocrits. None of the cod exhibited any of these symptoms.
Biology of Gatnmarellus angulosus (Crustacea, Amphipoda) in the Northwestern Atlantic
Authors: Steele D. H. , Steele V. J.
Published: April 2011

Gammarellus angulosus is a littoral Atlantic amphipod found from eastern Newfoundland south to the Cape Cod region. It is found clinging to algae of highly exposed rocky shores. The life cycle is 1 year. Fifty percent maturity of the females occurs at 8.8 mm. Mature females produce successive broods, except between September and November when they are in the resting stage. Fecundity increases with the size of the female. Young of the November brood are released from the females in May and adults disappear in the summer.
Blood Concentrations of Tricaine Methane Sulphonate in Brook Trout, Salvelinus fontinalis, During Anesthetization, Branchial Irrigation, and Recovery
Authors: Houston A. H. , Woods R. J.
Published: April 2011

Blood concentrations of tricaine methane sulphonate increased rapidly upon immersion of trout in 100 mg/liter solutions of the anesthetic at 3.5–5 C, and also rose significantly during irrigation for 15 min with either 50 or 100 mg/liter solutions. Clearance was rapid following transfer to running freshwater recovery tanks. Graphical estimates of 50 and 90% blood clearance times were 20 and 55 min, respectively.
Electrical Responses of the Olfactory Bulb of Pacific Salmon Oncorhynchus nerka and Oncorhynchus kisutch
Authors: Hara Toshiaki J.
Published: April 2011

Olfactory bulbar electrical responses elicited by nasal infusion of food extracts, hand rinse, and several amino acid solutions were studied in sockeye (Oncorhynchus nerka) and coho (O. kisutch) salmon from several different sources. Comparison was also made in rainbow trout (Salmo gairdneri). Significant variations in the olfactory bulbar responses were observed among different species and even among the same species from different sources. The estimated lowest threshold concentration for L-serine was between 10−6 and 10−7 M in salmon. Olfactory responses of rainbow trout were always several times larger than those of salmon.Pretreatment of nasal cavity with 10−4 M solutions of HgCl2 or CuSO4 (27 or 16 mg/liter, respectively) for 10 sec completely blocked the olfactory responses in all fish species studied. The effect was reversible; the responses returned to their original level by rinsing. Exposure of fish to 0.1 mg/liter HgCl2 for up to 3 days reduced the olfactory responses to 40–10% of those of normal fish. CuSO4 was the more toxic.
Effect of Two Iodophors on Bacterial and Fungal Fish Pathogens
Authors: Ross A. J. , Smith Cathy A.
Published: April 2011

In in-vitro tests on nine species of bacteria and two species of fungi, the majority of strains tested did not survive a 5-min exposure to either Betadine or Wescodyne at a concentration of 25 ppm active ingredient.
Fatty Acid Composition of Nephtys incisa and Yoldia limatula
Authors: Farrington John W. , Quinn James G. , Davis Wayne R.
Published: April 2011

Samples of the infaunal invertebrates Nephtys incisa and Yoldia limatula from Narragansett Bay, Rhode Island, have been analyzed for their fatty acid distribution. Based on total fatty acids, Yoldia contains 9–16% of an acid tentatively identified as 22:2. The ratios of 18:1/18:0 and 18:1/20:1 fatty acids of Nephtys from a polluted station in the bay are lower than the corresponding ratios for animals from relatively clean areas.
Genetics of Glycerol-3-phosphate Dehydrogenase Isozymes in White Muscle of Lake Whitefish (Coregonus clupeaformis)
Authors: Clayton J. W. , Franzin W. G. , Tretiak D. N.
Published: April 2011

Multiple isozymes of glycerol-3-phosphate dehydrogenase (L-gIycerol-3-phosphate: NAD oxidoreductase, E. C. 1.1.1.8) have been resolved by starch gel electrophoresis of extracts of muscle tissue from lake whitefish (Coregonus clupeaformis). The isozyme electropherograms show that three kinds of subunit, A, B, and C, are synthesized in red muscle and two of these, A and B, are also found in white muscle. In red muscle the subunits evidently combine to form catalytically active dimers of the following types: AA, AB, BB, BC, and CC. In white muscle only the AA, AB, and BB dimers were observed.A genetic and molecular structure model is proposed for the glycerol-3-phosphate dehydrogenase (G-3-PDH) isozymes in white muscle of lake whitefish. On the basis of two alleles for A subunits and three alleles for B subunits, the model predicts a total of 18 distinct, electrophoretic G-3-PDH phenotypes for all possible AA, AB, and BB dimeric isozymes. The model has been confirmed by the results of a breeding experiment that tested the heritability of each of the five known alleles. A difference in the rate of heat inactivation of AA and BB isozymes was also interpreted as additional evidence for the unique genetic and molecular nature of the two kinds of subunits.Surveys of natural populations of lake whitefish revealed some marked variations in the frequencies of G-3-PDH alleles in fish from different geographical areas.The cisco (Coregonus artedii) also appears to have three "b" alleles for G-3-PDH.
Effect of Simulated Meal Size on Gastric Acid and Pepsin Secretory Rates in Bluegill (Lepomis macrochirus)
Authors: Norms James S. , Norris David O. , Windell John T.
Published: April 2011

Rates of gastric acid and pepsin secretion into the gastric juice were examined in terms of enzymatic activity (measured spectrophotometrically as tyrosine released from hemoglobin substrate) and total gastric enzyme secretion (calculated from secretion of 14C-labelled protein) at various intervals up to 9 hr following introduction into the stomach of one or two glass beads representing approximately 0.62 and 1.26% of the bluegill (Lepomis macrochirus) body weight, respectively. Observations of enzymatic activity and concentration suggested that gastric secretory reserves would have been depleted 6 hr after consuming a meal equalling 1.26% of the fish body weight. Decreased acidity of gastric juice 5 hr after ingesting two glass beads supported this interpretation. The importance of these data to efficiency and growth studies is discussed.
The Seasonal Cycle of Vitamin B12 in the Strait of Georgia, British Columbia
Authors: Cattell S. Allen
Published: April 2011

The seasonal cycle of vitamin B12 in the Strait of Georgia, British Columbia, was studied over a 17-month period. The temporal and spatial distribution of this vitamin was found to be more complex than that of nitrate and phosphate in the Strait and B12 reported for other areas.The vitamin data are compared with inorganic nutrient distributions and physical characteristics of the Strait of Georgia to support the hypothesis that the observed heterogeneity of B12 is largely the result of vitamin–particulate matter interactions.
Choice of Colors of Food Items by Rainbow Trout (Salmo gairdneri)
Authors: Ginetz R. M. , Larkin P. A.
Published: April 2011

Rainbow trout in artificial stream situations were offered seven colors of dyed rainbow trout eggs in all combinations of two colors. Against a pale, greenish-blue background, in daylight, the color preference was: blue, red, black, orange, brown, yellow, and green. This order largely reflected contrast with background color; but, in addition, there were preferences for certain colors. Particular color combinations such as yellow and black, and yellow and blue, resulted in significantly higher total consumption. When background color was varied, preference was low for the color of eggs that matched the background, but the effect was not statistically demonstrable. At low light intensities the order of preference for various colors was yellow, red, blue, and black. The results collectively indicate keen color discrimination in rainbow trout and preferences for particular colors in particular environmental settings. These findings could have useful application to field situations where it is desirable to modify rates of predation on salmon fry by presenting other kinds of food to satiate predators.
A Stimulatory Apparatus for Studying the Olfactory Activity in Fishes
Authors: Hara T. J. , Law Y. M. C. , Veen E. Van der
Published: April 2011

An apparatus was designed for stimulating the olfactory organs of fishes. The advantage of this apparatus is that it can easily control the stimulus time and the interval between two stimuli either independently or sequentially. The apparatus can also, with slight modification, be applied to the gustatory systems.