bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Temperature on Serum Protein Components in the Killifish,Fundulus heteroclitus
Authors: Umminger Bruce L.
Published: April 2011

Electrophoretic patterns of serum proteins were studied in Fundulus heteroclitus acclimated to temperatures from 30 to −1.5 C. Microzone electrophoresis on cellulose acetate revealed eight distinct zones (seven anodal and one cathodal to the origin) at all temperatures. These zones were grouped into three larger zones (I, II, and III) for convenience in analysis. Low mobility proteins of zone III decreased in the cold to a greater degree than did high mobility proteins of zones II and I. The greater reduction in these low mobility proteins, which are comparable to human gamma globulins, might produce a less active immune response in cold-acclimated killifish.
Population Ecology of the Brook Trout, Salvelinus fontinalis, in Matamek Lake, Quebec
Authors: Saunders Lloyd H. , Power G.
Published: April 2011

Population estimates of an unexploited brook trout population at Matamek Lake, Quebec, indicated that more than 86% of the total population inhabited the tributaries of the lake during the summer of 1968. As opposed to the stream habitat, the combination stream–lake ecosystem moderated the mortality rates of the intermediate age-groups and allowed survival to higher ages in the population. Estimates of standing stock and production in the lake were 3.1 and 2.2 kg/ha respectively during 1968.The population was characterized by a slower growth rate, higher age at maturity, higher survival rate in the intermediate age-groups, and longer life span when compared with an exploited population in Wisconsin. Increased numbers of trout in higher age-groups at Matamek Lake were attributed to high survival rates in the intermediate age-groups in the absence of exploitation. Low estimates of standing stock and production were attributed to environmental factors affecting growth.
Effects of Acid Mine Wastes on Phytoplankton Communities of Two Northern Ontario Lakes
Authors: Johnson M. G. , Michalski M. F. P. , Christie A. E.
Published: April 2011

Differences in chemical composition in 1965–67 between two lakes contaminated by uranium-milling wastes and one unaffected lake were related directly to the nature of processes in uranium extraction and subsequent waste treatment. Low pH and high concentrations of SO4−2, NO3−1, and Ca+2 occurred in the contaminated lakes. Low concentrations of inorganic carbon, which apparently limited production in the contaminated waters, resulted from reduced solubility, loss, and possibly inefficient regeneration of CO2. Other major nutrients did not appear to be limiting, since nitrates were in greater supply in the contaminated lakes than in the unaffected lake and phosphorus and silica occurred in similar concentrations in all three lakes.Lower phytoplankton populations and lower indices of diversity were found in the contaminated lakes than in the unaffected one. Many species of Bacillariophyceae, Chrysophyceae, and Myxophyceae developed in the unaffected lake but were absent or occurred in extremely low numbers in the contaminated lakes.Average primary productivities were approximately 70 and 30 mg C m−2 day−1 in the two contaminated lakes and 130 mg C m−2 day−1 in the unaffected lake. In situ areal and volumetric measurements in laboratory and field bioassays confirmed the importance of inorganic carbon in limiting primary productivity. A potential compensatory mechanism in the contaminated lakes was a deepening of the euphotic zone. Although greater concentrations of inorganic carbon occurred and were assimilated in hypolimnetic than in epilimnetic waters, the mechanism was not sufficient to overcome the effects of reduction in both species diversity and abundance of phytoplankton on the areal primary productivity.
A Method of Surveying Scallop Populations From a Submersible
Authors: Caddy J. F.
Published: April 2011

A system is described for continuously recording density changes across a population of benthic organisms from a submersible. This system was tested in the Northumberland Strait over a population of scallops (Placopecten magellanicus). A continuous record of scallops visible from the viewport of the submersible was registered on a chart recorder, concurrently with a series of exposures by an externally mounted automatic camera. Transects up to 4 km long were completed in a single dive.A distance trace provided by a towed odometer wheel allowed visual counts to be expressed as linear densities (numbers seen per unit distance travelled) independently of submersible speed. An estimate of the width of visual field at a known height off bottom enabled linear densities to be converted into population densities (numbers seen per unit area of sea floor).Scallop distribution in the area was markedly contagious. Areas of high scallop density (up to 4.8 scallops/m2), of the order of 0.5 km across, on sand, were separated by stretches of mud where scallop density was below 0.1/m2.
Relationship of Gill Ventilation and Perfusion in Pacific Dogfish,Squalus suckleyi
Authors: Hanson David , Johansen Kjell
Published: April 2011

Unanesthetized specimens of Pacific dogfish, Squalus suckleyi, were used to study the relationships of oxygen uptake to ventilation and blood perfusion of the gills. Ventilation–perfusion ratios [Formula: see text] were determined over a wide range.In resting dogfish the [Formula: see text] ratios normally fell within the range of 10–20 at 6–10 C with a ventilation usually between 200 and 500 ml/min∙kg and a cardiac output between 20 and 40 ml/min∙kg. The extraction of oxygen from water varied from about 20 to 50% within that [Formula: see text] range, but at lower ratios the extraction was higher and sometimes exceeded 75%. When extraction was high the oxygen tension of expired water often fell below that of arterial blood thus indicating countercurrent gas exchange.The oxygen uptake varied almost directly with cardiac output over a wide range and with ventilation at low and normal water flows.Data are presented regarding the effectiveness of oxygen removal from water, oxygen uptake by blood, and overall transfer of oxygen from water to blood at various ventilations.In curarized dogfish the heart rate varied with changes of induced ventilation. The reflex nature of this cardiac and ventilatory coupling was revealed by its abolition when the fish were atropinized.
Estimation of Bone Material in Fish Protein Concentrates
Authors: Dambergs N. , Regier L. W.
Published: April 2011

An improved method for estimation of bone material in fish protein concentrates prepared from cod and herring is proposed. It is based on the difference of densities of dried protein and bone material.
Determining Cortisol and Cortisone Simultaneously in Salmonid Plasma by Competitive Protein Binding
Authors: Fagerlund U. H. M.
Published: April 2011

A method was developed for the simultaneous determination of nanogram quantities of cortisol and cortisone in 0.1-ml samples of salmonid plasma by competitive protein binding (CPB). The steroids were separated by thin-layer chromatography on silica gel and CPB analysis was performed with chicken serum in the presence of Florisil.
Scallop Sterols are Hypocholesterolemic Relative to Cholesterol for the Chick
Authors: Idler D. R. , Safe L. M. , MacKinnon G. A. , Proudfoot F. G.
Published: April 2011

Groups of 8-day-old chicks were fed 14 days on a standard diet, or on a standard diet supplemented with scallop sterols or cholesterol, or both. The blood cholesterol concentration increased significantly (P <.01) when.5% cholesterol was incorporated into the diet and there was a possible decrease (.05 < P <.10) when.5% scallop was fed.
Northern Range Extension of the Atlantic Mackerel, Scomber scombrus, to Black Island, Labrador
Authors: Parsons L. S.
Published: April 2011

During August 1969, 785 specimens of Scomber scombrus were captured in southern Labrador coastal waters, extending the known range in the western North Atlantic to Black Island, Labrador, more than 50 miles north of Triangle Harbour, the previously authenticated northern range limit.
Movement of Phosphate and Other Ions From and Through Lake Muds
Authors: Hynes H. B. N. , Greib B. J.
Published: April 2011

Laboratory experiments showed that sheets of polyethylene or a layer of sand placed on the surface of undisturbed lake mud reduce the loss of oxygen in the overlying water and greatly decrease the rate of release of phosphate, iron, and ammonium from the sediment. Polyethylene laid on disturbed mud produced the same effects, and it also reduced the rate of release of total ions as measured by electrical conductivity.Experiments with P32 showed that phosphate moves readily through undisturbed mud, and that the movement is not a biotic process. We also found that phosphate and ammonium injected 4 cm below the mud–water interface move upwards into the water, and that this applies to both a rich calcareous mud and a poor acid peaty one.We concluded that early reports of little movement of phosphate through muds are erroneous, possibly because they are based on short experiments, and that there is a great potential store of nutrient salts in enriched muds. This would greatly delay recovery of lakes that have been rendered eutrophic by pollution, so we suggest that polyethylene sheet laid on the sediments of valued lakes may serve to rehabilitate them more rapidly.
Diel Vertical Migration of Pandalus borealis in Kachemak Bay, Alaska
Authors: Barr Louis
Published: April 2011

Catches of Pandalus borealis by surface-to-bottom pot fishing in Kachemak Bay, Alaska, showed that this species was distributed in large numbers throughout the water column at night and suggested a diel vertical migration. The shrimp apparently left the vicinity of the bottom about dusk and returned about dawn; the apparent length of time they were off bottom was directly related to the length of the night. Bottom trawling clearly showed lower availability of P. borealis on bottom at night than during the day. Catches of shrimp by pot fishing and trawling indicated that small P. borealis have a greater tendency to migrate vertically than the larger individuals.
Distribution, Growth, and Seasonal Abundance of Hyalella azteca (Amphipoda) in Relation to Sediment Microflora
Authors: Hargrave Barry T.
Published: April 2011

Growth, density, and body size of the deposit-feeding amphipod Hyalella azteca, and its food, epibenthic algae, and sediment microflora, were greatest in shallow-water areas of Marion Lake. The vertical distribution of Hyalella was limited to the upper 2 cm of sediment cores. Highest concentrations of sedimentary chlorophyll and lowest concentrations of nondigestible ligninlike material also occurred at the sediment surface.In laboratory substrate-choice experiments, Hyalella differentiated between sediments with different concentrations of microorganisms, and growth depended upon the quantity of microflora in the diet. In Marion Lake, increased growth of Hyalella during June was independent of temperature and closely correlated with increased rates of epibenthic primary production.Egg production, related to body size in a nonlinear manner, began during May as growth rates increased. As a combined result of egg production and juvenile survival, the maximum density of Hyalella in Marion Lake was reached in August.
A Comparison between Two Sonic Measuring Systems for Demersal Fish
Authors: Dowd R. G. , Bakken E. , Nakken O.
Published: April 2011

Two sonic methods for estimation of abundance of fish stocks, the echo integrator and the digital counter methods, were compared on single and schooling fish in the Lofoten area of Norway during March 1969. Good correlation was obtained between the two systems for both situations, but the slopes of the regressions of integrated values on the digital counter differed significantly between low and high density fish concentrations. This suggests that the two systems treated the echo information differently, but nevertheless maintained a linear relation between themselves over a wide range of counts.
Development of Salinity Preference in Pre-Smolt Coho Salmon, Oncorhynchus kisutch
Authors: Otto Robert G. , McInerney John E.
Published: April 2011

When tested in a horizontal salinity gradient, freshwater-adapted coho salmon exhibited a bimodal preference response throughout most of the pre-smolt period. Preference modes were located at fresh water and at a salinity intermediate between fresh and sea water. The concentration of the higher preferred salinity changed both with time and instantaneously with the dimensions of the test gradient. Fish tested in a gradient that originated at 4‰ exhibited a single preferred salinity at 7‰ in June, which increased gradually to 13‰ by February. The same fish tested in a gradient originating at fresh water showed a corresponding preference for an intermediate salinity in addition to their preference for fresh water. However, this second preferendum was at a somewhat lower salinity than that observed in tests in which fresh water was excluded from the gradient.With the approach of the smolt transformation, preference for fresh water was greatly reduced and the response distribution became unimodal. At no time during the period prior to the smolt transformation did the preferred salinity exceed 14‰.
Glucose Levels in FreshTilapiaMuscle
Authors: Hoffman A. , Disney J. G. , Grimwood B. E. , Jones N. R.
Published: April 2011

The glucose content of Tilapia muscle from fish of different physiological condition was estimated at the time of death. Glucose was found to be present in all instances but the amount was considerably greater in rested aquarium fish than in exercised pond-reared fish.
An Incidence of Parasitism of Deepwater King Crab, Lithodes aequispina, by the Barnacle Briarosaccus callosus
Authors: McMullen John C. , Yoshihara Harvey T.
Published: April 2011

Parasitism of commercially important anomuran crabs in Alaskan waters by the rhizocephalan Briarosaccus callosus Boschma has been documented twice. One specimen from the Bering Sea was hosted by the deepwater king crab, Lithodes aequispina, and two others were found among a group of 99 king crab, Paralithodes camtschatica (Tilesius), in southeastern Alaska. In July 1969, 14 of 21 L. aequispina captured near Kodiak Island were found to be infected with B. callosus. The high incidence of infection is the first documentation of B. callosus in the upper Gulf of Alaska, where research on anomuran crabs has been conducted for about 12 years.
A Generalization of the Murphy Catch Equation
Authors: Tomlinson Patrick K.
Published: April 2011

Given catches, by time intervals, from a known cohort of fish with known natural mortality rate and known fishing mortality rate for either the first or last time interval, the population size at the beginning of each interval and the fishing mortality rate during each interval may be estimated using a generalized Murphy catch equation. The generalized equation is constructed from the ratio of catches in successive intervals and depends on the assumption of simple exponential mortality within the intervals. The intervals may vary in length and have zero catches. The estimates may be badly biased depending on the nature of the catch sequence and the independent estimates of natural mortality and fishing mortality used to start the procedure.
Stimulation and Photography of Bioluminescence in Lanternfishes (Myctophidae)
Authors: Anctil M. , Gruchy C. G.
Published: April 2011

Hydrogen peroxide injections and application evoked luminescence in Tarletonbeania crenularis taylori and Protomyctophum thompsoni, but did not cause Stenobrachius leucopsarus to luminesce. Neither formalin nor electric shock were especially effective in stimulating luminescence in any of the above three species. The luminescent organs of myctophids were photographed by their own light.
Some Lernaeopodidae (Copepoda) from Fishes of British Columbia
Authors: Kabata Z.
Published: April 2011

Nine species of copepods in the family Lernaeopodidae were collected as parasites of teleost or elasmobranch fishes common to coastal waters of British Columbia. One species (Schistobrachia tertia) has not been previously described. Two species (Dendrapta cameroni longiclavata and Lernaeopodina pacifica) are new records for the Canadian fauna. The remaining six include Pseudocharopinus dentatus, Clavella adunca, and detailed descriptions of Clavella parva, Clavella perfida, Nectobranchia indivisa, and Brachiella robusta, the last-named displaying a range of morphological variability hitherto unknown in Lernaeopodidae.
Parasites of the Threespine Stickleback (Gasterosteus aculeatus) in Newfoundland and Labrador
Authors: Hanek George , Threlfall William
Published: April 2011

Fifteen genera of helminths (19 species) and two genera of parasitic copepods (2 species) were recovered from 375 threespine sticklebacks (Gasterosteus aculeatus Linnaeus, 1758) taken in 10 sampling areas in Newfoundland and Labrador during 1968 and 1969. Two new host records and two new records for North America are included.
Body Composition Changes During Growth in Young Sockeye (Oncorhynchus nerka) in Fresh Water
Authors: Groves T. D. D.
Published: April 2011

The body composition of young sockeye (Oncorhynchus nerka) in the weight range of 0.5–300 g was investigated to further document changes in body composition with growth, and to develop equations that would allow the estimation of total body composition in this species, either in vitro or in vivo, based on easily measured parameters such as fork length, live weight, and total body water. The major components of the fat-free mass (protein, water, and ash) in nonstarving fish were closely related to each other and to fork length. Body fat tended to increase with size, but was not closely related to the other components of body composition. The following equations were derived, allowing the accurate estimation of total water (W), protein (P), and fat-free dry material (FFDM, consisting of protein and ash) in grams, based on the measurement of either water or fork length (L) in centimeters: W = 0.00571 L3.118, P = 0.204 W 1.038, and FFDM = 1.113 P. Body fat (F) may be estimated as the difference between wet body weight (M) and the lean mass: F = M − (W + FFDM).These equations are similar to, but not identical to, the relations derived for other species of salmon, based on other published data, and to the respective relations reported in the literature for mammals. The applications of these equations to the nutritional evaluation of wild populations and to quantitative nutritional studies on young sockeye are discussed and illustrated.
Use of Ultraviolet Light to find Parasitic Nematodes in situ
Authors: Pippy John H. C.
Published: April 2011

The parasitic nematodes Anisakis sp., Contracaecum aduncum, and Phocanema decipiens fluoresce when irradiated by ultraviolet light (360 mμ). Fluorescence greatly simplifies searching for the nematodes in situ when they are not deeply embedded in host tissues. Also, differences in fluorescence quality enable immediate preliminary identification of specimens. The method is particularly well suited for long-term investigations or when accurate counts are necessary.
A Relation of Size to Swimming Speed in Rainbow Trout
Authors: Fry F. E. J. , Cox E. T.
Published: April 2011

Cruising speed at 10 C of rainbow trout 4–100 g was measured in a rotating chamber and found to vary as weight0.13. Weight varied as length2.91, so that swimming speed was dependent on length0.4, close to the relation found for other salmonids by other authors. A 10-g fish could swim at approximately 9 body lengths (L) sec−1 whereas at 100 g the cruising speed was 5.5 L sec−1. By extrapolation the rate at 1000 g was 3 L sec−1.
Mortality of Dart-Tagged Captive Sablefish (Anoplopoma fimbria)
Authors: Kennedy W. A.
Published: April 2011

Infection from dart tags killed sablefish (Anoplopoma fimbria) in a tank and in a net. Mortality began 3 months after tagging and reached a high level after 8 months that persisted for more than a year. At the observed mortality rate virtually all would die within a year.
Some Aspects of the Ecology of the Parasite Fauna of the Gills of Yellow Perch, Perca flavescens
Authors: Tedla Shibru , Fernando C. H.
Published: April 2011

Three parasites, the monogenean Urocleidius adspectus, the copepod Ergasilus confusus, and the glochidia of Lampsilis radiata, were common on the gills of the yellow perch collected from the Bay of Quinte, Lake Ontario, from May 1967 to April 1968. No correlation was found between the incidences of infestation of these three parasites. Except for the glochidia, more parasites were found on the second and third gill arches than on the first and fourth. Other records from the gills were the glochidia of Elliptio complanatus, the myxosporidian Henneguya sp., and nonparasitic mites belonging to Hydrozetes sp.
Visual Observation of Fish Beneath the Ice in a Winterkill Lake
Authors: Magnuson John J. , Karlen Duane J.
Published: April 2011

A device is described to directly observe fish behavior beneath the ice of a shallow lake. The viewing device, a 1.9-m tall plexiglass tube (14.0 cm inside diameter) sealed at the bottom, worked on the principle of a periscope. It was frozen into place in the center of a net enclosure. A man in a darkened hut lowered a mirror into the tube to observe the fish in the enclosure.Vertical distributions and behavior of 5 adult northern pike (Esox lucius), 6 yellow perch (Perca flavescens), and 13 bluegill (Lepomis macrochirus) were compared with the levels of dissolved oxygen, free carbon dioxide, hydrogen sulfide, and water temperature. Observations in Mystery Lake, Wisconsin, were from December 29, 1968, through January 30, 1969, during a period when environmental conditions worsened beneath the ice and resulted in a winterkill.Yellow perch were the most active, northern pike the least. Bluegill remained farther beneath the ice than did the other two species. Northern pike took up residence in domes that they formed in the undersurface of the ice. Northern pike and yellow perch frequently sounded into the anoxic layers.We conclude that differences in fish behavior were significant in prolonging survival. A combination of little locomotory activity and a position immediately beneath the ice apparently favored the longer survival of northern pike over bluegill and yellow perch.
Exploitation of Self-Sustaining Ontario Stream Populations of Brown Trout (Salmo trutta) and Brook Trout (Salvelinus fontinalis)
Authors: Marshall T. Lawrence , MacCrimmon Hugh R.
Published: April 2011

The August standing crop of harvestable brown trout (Salmo trutta, 90%), and brook trout (Salvelinus fontinalis, 9%) in the upper Sydenham River, Ont., was estimated at 499 trout/ha (63.2 kg/ha) during 1966 and 1967. Brown trout were of age I (68%), age II (23%), and the remainder of ages III, IV, V, and XIII. Brook trout were ages I (95%) and II only.The average annual harvest by 1501 anglers was 1135 fish (64% brown, 35% brook trout) at a rate of 0.34 fish/hr. Exploitation of the preseason standing populations of brown and brook trout was 23 and 59%, respectively. Catch per unit effort from the downriver section (all brown trout of ages II–IV and mean length of 34.0 cm) averaged 0.10 at an angling pressure of 264 hr/ha. An upriver section occupied predominantly (90%) by brown trout of age I–III and mean length of 26.8 cm yielded 0.67 trout/hr at an angling pressure of 251 hr/ha.The population structure, growth, and exploitation rate of naturalized brown trout favours its use in providing continuous angling of creditable quality in heavily fished headwater streams. Coexistence of self-sustaining populations of brown and brook trout provide a sustained, high-quality mixed fishery.
Locomotor Responses of Blinded Goldfish (Carassius auratus) to Remote Perception of Barriers
Authors: Timms A. M. , Kleerekoper H.
Published: April 2011

Comparison of locomotor responses of blinded goldfish with those reported for normal animals on approaching the walls of an experimental tank demonstrated that although visual perception of the walls played no role in the modification of frequency distribution of size of angles of turns, it was necessary for the observed change in velocity of locomotion. Observations on fish blinded in only one eye suggested that perspective vision was required for the control of turning frequency.
Genetics of Multiple Lactate Dehydrogenase Isozymes in Muscle Tissue of Lake Whitefish (Coregonus clupeaformis)
Authors: Clayton J. W. , Franzin W. G.
Published: April 2011

Electrophoresis of extracts of red lateral line muscle from lake whitefish (Coregonus clupeaformis) revealed two groups of lactate dehydrogenase (LDH) isozymes. In heart tissue extracts the faster moving set of isozymes predominated whereas most of the LDH in white muscle consisted of the slower set of electrophoretic isozymes.Three phenotypes of heart-type LDH isozymes were found in wild fish. Breeding experiments showed that there were two nondominant alleles at the locus coding the most anodal of the heart-type LDH subunits. The frequencies of these alleles were different in fish from two lakes.Our observations regarding the presence of discrete sets of multiple LDH isozymes in lake whitefish and the independent genetic control of isozymes within each set provide additional evidence for the probable tetraploid nature of salmonids.
Survey of Marine Borers in Canadian Atlantic Waters
Authors: Bohn A. , Walden C. C.
Published: April 2011

A survey of the maritime waters of Canada's Atlantic provinces disclosed only the teredine borer Teredo navalis and the limnorial borer Limnoria lignorum. The distribution of L. lignorum was virtually ubiquitous, whereas T. navalis was confined to areas where water temperatures exceeded 15–16 C for some period of the year.
Spawning Habits of the Largescale Sucker, Catostomus macrocheilus, at Stave Lake, British Columbia
Authors: McCart P. , Aspinwall Nevin
Published: April 2011

The spawning habits of the largescale sucker, Catostomus macrocheilus, were studied in the watershed of Stave Lake, British Columbia, during the spring of 1967. Spawning occurs in a variety of physical situations, in the inlet and outlet streams of lakes and on the gravelled lakeshores themselves. Spawning acts were observed during the day in some streams and at night in others. The largescale sucker is a mass spawner, with several males attending a single female. The eggs are deposited on, and beneath, the gravel surface. The spawning act is also described.
Fish and Crayfish Mortalities Due to an Internal Seiche in Georgian Bay, Lake Huron
Authors: Emery Alan R.
Published: April 2011

An internal seiche in Georgian Bay, Lake Huron, altered water temperatures and transparency in Little Dunks Bay (a small shallow bay). A sudden decrease in temperature was the probable cause of mortalities in sculpins (Cottus bairdi) and crayfish (Orconectes propinquus) as well as of marked changes in behavior of other fish species. Trout-perch (Percopsis omiscomaycus) appeared unaffected.
Rates of Gastric Emptying in Young Cod
Authors: Tyler A. V.
Published: April 2011

Stomachs of young cod were opened at various time intervals after they had voluntarily eaten measured meals. More digested food left the stomach in the first few hours after the meal was given than towards the end of digestion. Instantaneous depletion rate increased rapidly with increase in acclimation temperature from 2 to 15 C. The rate was not increased at 19 C and was possibly depressed. Fish would not feed at 21 C. When meal size was varied, a straight-line relation was found between rate of gastric emptying and quantity of food in the stomach. This implies that in young cod intestinal absorption is coupled to food intake by regulation of the gastric volume. It is likely that digestion rate data could be used to estimate daily rations for fish in their own environment by measuring quantity of food in the stomach.
Effects of Gravel Size, Egg Depth, and Egg Density on Intragravel Movement and Emergence of Coho Salmon (Oncorhynchus kisutch) Alevins
Authors: Dill L. M. , Northcote T. G.
Published: April 2011

In experimental aquaria with large gravel (3.2–6.3 cm), vertical and lateral movements of coho salmon (Oncorhynchus kisutch) alevins were more extensive and area utilized per alevin was greater than in small gravel (1.9–3.2 cm). At low density (50 per aquarium) the alevins moved farther towards the inlet, but the mean area occupied per alevin was the same as that at high density (100 per aquarium). Burial depths tested (20 and 30 cm) had no significant effect on vertical or lateral movements or on area utilized per alevin. Alevin orientation in the gravel, survival to emergence, and timing of emergence were not affected by any of the environmental variables examined.
Some Aspects of the Organization of Fish Schools
Authors: Olst Jon C. van , Hunter John R.
Published: April 2011

The objective of this study was to describe the organization of schools of the pelagic marine fishes Scomber japonicus, Trachurus symmetricus, Engraulis mordax, Atherinopsis californiensis, and Atherinops affinis. Organization was studied in larval through adult stages by analysis of spatial and angular relations among fish in dorsal photographs of schools.In all species, schools of young fish, larval and juveniles, were typically less compact and showed greater differences in angular headings than did schools of adult fish. The rate at which school structure changed with size varied among species; it was rapid in Scomber and the atherinids and slower in Engraulis and Trachurus. School organization differed among species at the adult stage. Schools of Scomber were typically the most compact and organized; Trachurus and Engraulis schools were intermediate in their organization and Atherinops schools were the least organized.Spatial and angular measurements were also used to develop inferences regarding the "following reaction" in four of the species. The similarity in angular headings between fish was used as the criterion of following. These analyses showed that the similarities in headings between two fish in a school decreased with the distance they were apart. The headings most alike between adjacent fish in a school were between those in file. These results suggested that the neighbor directly ahead of a given fish in a school is used more frequently as an angular reference for the following reaction than ones to the side.Analysis of the distances between neighbors in the four species indicated that fish were closer to adjacent neighbors in the file than they were to ones in rank. This suggested that spacing in the horizontal plane might be related to tail movement.
Long-Terra Changes in the Limnology and Macrozooplankton of a Large British Columbia Lake
Authors: Zyblut E. R.
Published: April 2011

Macrozooplankton distribution and abundance as well as limnological conditions were compared during 1949 and 1964 in Kootenay Lake, a large oligotrophic lake in southeastern British Columbia. The standing crop of macrozooplankton increased two- to threefold over 15 years. Changes in physical–chemical limnological conditions, such as a decrease in depth of light penetration, and increases in pH, specific conductivity, dissolved nutrients, and phosphates also occurred, indicating an increase in productivity.The most noticeable change in macrozooplankton was a shift in cladoceran species composition in the north arm of the lake, formerly dominated by Daphnia but now by Diaphanosoma. Size-selective predation, differences in food availability, and competition for food with Diaphanosoma and Mysis relicta are suggested to be responsible for changes in the spatial distribution of Daphnia since 1949.Examination of changes in midsummer zooplankton abundance between successive years (1964–66) indicated that total zooplankton was least abundant in 1964. Differences in abundance during this period were small when compared with those between 1949 and 1964.
Growth and Reproduction of the Lanternfish Stenobrachius leucopsarus
Authors: Smoker William , Pearcy William G.
Published: April 2011

Growth and reproductive patterns of the common lanternfish Stenobrachius leucopsarus (Eigenmann and Eigenmann) are described by length-frequency analysis, otolith analysis, and examination of ovaries. Length-frequency analysis showed that growth is approximately linear, 1.59 mm standard length per month, during the 2nd, 3rd, and part of the 4th year of life. Yearling fish average 23 mm long, 2-year-olds 41 mm, and 3-year-olds 59 mm.Otolith analyses indicate that some fish may live to be 8 years old, but confidence in this method is limited to fish 5 years old or younger. Fitting mean lengths of age-groups defined by otolith analyses with the von Bertalanffy equation gave L∞ = 85 mm, k = 0.34. Back calculation of lengths at the times of formation of otolith annuli gave another set of estimated mean lengths of age-groups, which, fitted by the von Bertalanffy equation, describes a growth curve similar to the one described by otolith analyses. The inflection in growth in weight occurs at about 4 years of age.Time of spawning, determined from egg measurements, occurs from December to March. Reproductively mature individuals are 4 years old and older. Recruitment of young size groups is also seasonal, 20- to 25-mm individuals appearing in largest proportions in trawl samples in the winter, presumably about 8 months after spawning.Comparison with other studies indicates that spawning may occur earlier in Monterey Bay, California, than off Oregon, but growth rates and sizes of age-groups I–V are similar. Comparisons with published results of otolith analyses show similar age determinations for the smaller size groups.
Morphology of Certain Viruses of Salmonid Fishes. I. In vitro Studies of some Viruses Causing Hematopoietic Necrosis
Authors: Amend Donald F. , Chambers Velma C.
Published: April 2011

An electron microscope study was performed on three virus isolates that caused hematopoietic necrosis in salmonid fishes: infectious hematopoietic necrosis (IHN), Oregon Sockeye Disease (OSD), and Sacramento River Chinook Salmon Disease (SRCD). All three isolates were examined by negative staining of fathead minnow (FHM) monolayer tissue culture concentrates and IHN virus was also examined in thin sections of FHM cells. Viruslike particles were observed in infected tissues, but similar structures were not found in uninfected cultures. All three isolates were bullet-shaped, but oval and truncated forms were also observed. Mean measurements of particles from IHN-virus-infected tissue were 158 × 90 mμ. They consisted of an outer coat 15 mμ thick, a core 60 mμ in diameter, subunits about 5 mμ, and an axial pore about 20 mμ in diameter. These particles also were seen budding from the cytoplasmic membrane. Similar particles from SRCD were 159 × 90 mμ and isolates from OSD were 181 × 91 mμ. The three isolates were morphologically indistinguishable from one another and the greater length of OSD was considered insignificant. IHN, SRCD, and OSD viruses were tentatively placed in the rhabdovirus group, but serological studies are needed to determine if they are antigenically identical or should be included as separate members. Biochemical and physical characteristics of these viruses and a comparison with other salmonid viruses is also discussed.
Influence of Photoperiod on Smolt Development and Growth of Atlantic Salmon (Salmo solar)
Authors: Saunders Richard L. , Henderson Eugene B.
Published: April 2011

Atlantic salmon (Salmo salar) subjected in the spring to a constant photoperiod of 13 hr light/day or to simulated natural photoperiod (increasing day length) smoltified and grew rapidly before and after entering sea water. Others subjected to the reciprocal (complement) of natural photoperiod (decreasing day length in the spring) had the silvery color of smolts and grew rapidly but, unlike smolts, developed high condition factors while in fresh water. After they were transferred to sea water these fish ate less, grew more slowly, and had lower efficiencies of food conversion than those subjected to natural and constant photoperiod.Salmon experiencing reciprocal photoperiod had decreased sensitivity to external stimuli, suggesting reduced thyroid activity. Histological studies in June showed no differences in the appearance of the thyroid glands, suggesting no difference in thyroid activity between groups in natural and reciprocal photoperiod. Nor was there any difference in plasma osmotic and chloride levels between natural and reciprocal photoperiod groups, either in routinely active or fatigued fish.It is suggested that photoperiod acts through the endocrine system to affect growth patterns during and after smoking and possibly certain aspects of the smolting process itself. Effects of photoperiod on smolting and growth of salmon are discussed in connection with other cyclical changes in salmonid physiology known to be influenced by photoperiod.
Metazoan Parasites, Excluding Monogenea, from Longnose and White Suckers
Authors: Threlfall William , Hanek George
Published: April 2011

Seven genera of helminths (two of Digenea, one of Cestoda, and two each of Nematoda and Acanthocephala) and one species of parasitic copepod were recovered from 40 longnose suckers (Catostomus catostomus) and five white suckers (Catostomus commersoni), caught at two localities in Labrador, during August and September 1969. The helminths reported include five new host records.
Sporulation of a Haplosporidan in a Pacific Oyster (Crassostrea gigas) in Humboldt Bay, California
Authors: Katkansky Stanley C. , Warner Ronald W.
Published: April 2011

A Pacific oyster (Crassostrea gigas) with large numbers of acid-fast spores was collected from Humboldt Bay, California, in August 1969. The spores were tentatively identified as belonging to a haplosporidan of the genus Minchinia. This is the first report of sporulation of a haplosporidan in a Pacific oyster from the United States.
Further Studies on Scallop Sterols in Relation to Cholesterol in the Chick
Authors: Idler D. R. , MacKinnon G. A. , Cox Allan C.
Published: April 2011

The blood cholesterol concentration of chicks fed a cholesterol-supplemented diet decreased significantly (P < 0.05) when scallop sterols were added to the diet. There was no significant change in plasma Δ5-sterol when scallop sterols were incorporated into the basal diet.
Effects of Rotenone on Zooplankton Communities and a Study of their Recovery Patterns in Two Mountain Lakes in Alberta
Authors: Anderson R. Stewart
Published: April 2011

The devastation and recovery of the zooplankton communities were studied in conjunction with the application of rotenone to two mountain lakes in Jasper National Park. Crustacean plankters were absent for about 6 months after treatment, but rotifers and net phytoplankton were never completely absent. All crustacean species except one reached prerotenone abundance in about 3 years, probably the minimum time for recovery in these lakes.The speed of recovery is likely related to fecundity, time of reproduction, and the presence of resistant stages. Diaptomus sicilis had not reached reproductive maturity when rotenone was applied, and it was the last species to recover to its original numbers.Some species not found in samples before application were found in small numbers afterwards, probably due in part to movement from the littoral into the limnetic zone. In both lakes, blooms of small cladocerans after treatment were soon supplanted by increases in large cladoceran numbers. Most variations in composition and abundance after rotenone were likely due to changes in competition and predation pressures rather than to changes in environmental factors or to direct effects of rotenone.
Digestive Enzymes of the American Lobster (Homarus americanus)
Authors: Brockerhoff H. , Hoyle R. J. , Hwang P. C.
Published: April 2011

Gastric juice of lobster hydrolyzed the following substrates: triolein (enzymic activity: lipase), tributyrin ("lipase"), Azocoll(R) (proteinase), TAME and BAEE ("trypsin"), ATEE ("chymotrypsin"), HPLA ("carboxypeptidase A"), DNA (deoxyribonuclease), RNA (ribonuclease), p-nitrophenyl-phosphate (phosphatase), and p-nitrophenyl-N-acetyl-β-glucosaminide (chitobiase). (The quotation marks signify that the substrate specificities are typical of the quoted enzymes of mammalian or microbial origin. The spectra of specificities, however, of these enzymes and the corresponding enzymes of lobster are not necessarily identical.) Very low activities were found against RBB-starch (amylase) p-nitro-phenyl-α-(and β)-glucopyranoside(α- and β-glucosidase), p-nitrophenyl-β-galactopyranoside (β-galactosidase), and chitin azure (chitinase). No activities corresponding to phospholipase (lecithin), carboxypeptidase B (benzoylglycyl-L-arginine), elastase, glycylglycine dipeptidase, or leucine aminopeptidase were found.Gel filtration of gastric juice proteins on Sephadex(R) G-100 yielded estimates of molecular weights, among them: chitobiase 100,000; phosphatase 80,000; lipase 43,000; DNase 33,000; "trypsin" and ribonuclease 25,000; and two proteinases with optima around pH 4 and 8 and the low molecular weight of 12,500; proteolytic activity at pH 4 was also associated with the molecular weights 25,000 and 50,000.In ion-exchange chromatography, enzymes were eluted from DEAE-cellulose in the following sequence of increasing anionic character: chitobiase, proteinase (pH 4), proteinase (pH 8), lipase, "carboxypeptidase A," DNase, phosphatase, and "trypsin" and "chymotrypsin."Of the principal enzymes, only one (chitobiase) had its optimum at the pH 5 normal for lobster gastric juice. The lipase had an optimal pH around 7, phosphatase near 9, and "trypsin" near 8; proteolytic activity shows a maximum at pH 7–8 and another maximum, unusual for Crustacea, at pH 4.Much of the protein of gastric juice could not be connected with any enzymic activity. The proportion of nonactive protein seemed to increase with starvation of the animals. We found no evidence for the occurrence of zymogens.
Morphology of Certain Viruses of Salmonid Fishes. II. In vivo Studies of Infectious Hematopoietic Necrosis Virus
Authors: Amend Donald F. , Chambers Velma C.
Published: April 2011

Juvenile sockeye salmon (Oncorhynchus nerka) were injected with the infectious hematopoietic necrosis (IHN) virus, and tissue samples from the anterior kidney, spleen, liver, intestine, and pyloric caeca of moribund fish were prepared for electron microscopy. Bullet-shaped virus particles measuring 158 × 90 mμ were observed in the hematopoietic tissues of the anterior kidney and spleen. Virus particles were also observed in the outer connective tissues of the pancreas or pyloric caeca, or both. No virus was found in the intestine or liver. The healthy appearance of erythrocytes, reticular cells, and endothelial cells in necrotic areas of the spleen and anterior kidney, and the absence of lymphocytes in these areas, suggested that lymphocytes might be one source of the virus.
Effects of Copepod Grazing on Two Natural Phytoplankton Populations
Authors: Hargrave Barry T. , Geen Glen H.
Published: April 2011

Feeding and filtration rates of four species of copepods (Pseudocalanus minutus, Temora longicornis, Oithona similis, and Acartia tonsa) from Bras d'Or Lake and Morrison's Pond, Cape Breton Island, N.S., were measured in the laboratory with natural populations of phytoplankton. Adult copepods ingested all sizes of flagellates (1–15 μ in maximum dimension) but 5–15-μ cells were removed most efficiently. Ceratium sp. and Chaetoceros sp., principal spring and winter forms, were not utilized. Feeding rate declined as the number of animals per liter and the duration of the experiment increased. Estimates of feeding rates in nature were derived by extrapolation from the results of laboratory experiments. A comparison of estimates of mean summer primary production at the depths of maximum photosynthesis and daily zooplankton food intake suggested that, at those depths, zooplankton in Bras d'Or Lake consumed all the average daily production whereas 66% was removed in Morrison's Pond. The remaining production in Morrison's Pond probably contributed to the support of large rotifer and ciliate populations not found in Bras d'Or Lake. Natural concentrations of flagellates were more than sufficient to meet copepod respiratory energy requirements under laboratory conditions.
Evaluation of a Revised Hatchery Method Tested on Pink and Chum Salmon Fry
Authors: Bams R. A.
Published: April 2011

An artificial incubation method employing filtered river water and a gravel substrate was compared with natural propagation in a test on pink (Oncorhynchus gorbuscha) and chum (O. keta) salmon, at Hooknose Creek, King Island, B.C. At time of migration, about 70% of the hatchery pink fry were similar to the wild fry in stage of development; the remainder were immature. A similar but less pronounced difference occurred in the chum. Average rates of development were the same in the hatchery and the creek for each species. These two phenomena combined resulted in the hatchery fry of both species migrating, on the average, from 1 to 2 weeks earlier than the wild fry.Growth during incubation was the same in hatchery and creek, i.e., no loss of potential size occurred in this hatchery environment. Survivals in the hatchery were higher than in the creek, but were less than expected on the basis of experiments carried out elsewhere. Hatchery pink fry showed a lower variability in mean lengths and weights than did creek fry, possibly in response to greater homogeneity of the incubational environment. Chum fry from the last part of the creek runs showed evidence of postemergent growth in fresh water.
Walleye Fishery of Lake Erie in 1943–62 with Emphasis on Contributions of the 1942–61 Year-Classes
Authors: Parsons John W.
Published: April 2011

The commercial fishery for walleyes (Stizostedion vitreum vitreum) in Lake Erie virtually collapsed in the late 1950's. The extreme decline in production was attributed primarily to a succession of weak year-classes, caused by habitat deterioration (increased water temperatures, enrichment, and pollution) in western Lake Erie. Unusually high fishing intensity and high yields of walleyes in the mid-1950's contributed to the collapse.Annual lakewide production of walleyes dropped from a record high of 15 million lb in 1956 to a record low of 717,000 lb in 1962. Canadian catches exceeded those of the United States only during the high production years of 1956–58; U.S. fishermen took 71% of the total catch in 1915–62.On the basis of the numbers of fish of the various year-classes in the fall trapnet samples at Sandusky, Ohio, in 1943–62, all but one of the 1942–52 year-classes were above average strength, and all but one of the 1953–61 year-classes were below average. Fish of the 1953–61 year-classes grew much faster than those of the 1942–52 year-classes. The strong 1948 year-class was followed by a series of progressively weaker year-classes until 1958; year-class strengths remained low through 1962.
Significance of the Food Chain in DDT Accumulation by Fish
Authors: Macek Kenneth J. , Korn Sidney
Published: April 2011

Brook trout accumulated approximately 10 times more of the available DDT from the food than directly from the water. Since, in aquatic environments, the concentration of DDT is usually much higher in the food chain than in the water, we suggest that the food chain is the major source of DDT for fish in natural waters.