bluuebunny/crossref_metadata_2025 huggingface dataset:
World Distribution of Rainbow Trout (Salmo gairdneri): Further Observations
Authors: MacCrimmon Hugh R.
Published: April 2011

This note supplements a previous paper on the world distribution of the rainbow trout (Salmo gairdneri). While strong public acceptance of the species as a sport and food fish is expected to intensify the propagation and use of wild and domestic strains, no significant extension in naturalized range is anticipated because of environmental limitations.
Food of Larval Sea Lamprey (Petromyzon marinus) and American Brook Lamprey (Lampetra lamottei)
Authors: Moore J. W. , Beamish F. W. H.
Published: April 2011

Throughout the year, algae were the most frequently encountered organisms in the gut of larvae of landlocked and anadromous sea lamprey (Petromyzon marinus) and American brook lamprey (Lampetra lamottei). Relative abundance of organisms in the gut of both species was similar and did not change with length of larvae. In general, relative abundance of organisms in the gut was similar to that in samples of sediment and water. Occasionally, filamentous and episammic forms were not ingested because of their larger size.The number of algal cells ingested per unit weight of sea lamprey decreased inversely with size of larvae. In the summer the number of algal cells in the gut was about thrice that found in the winter for larvae of comparable size. Survival among diatoms evacuated from the digestive tract varied from 45% in July (17.8 C) to 90% in January (0 C). Representatives of the Achnanthes had the lowest survival rate (10–20%), while those of Amphora and Cyclotella had the highest (65–100%). Complete evacuation required approximately 54 and 70 hr at 16.0 and 2.5 C, respectively. Evacuation rate did not differ among the organisms consumed. The numbers of algae consumed by larval sea lamprey in a stream relative to their estimated abundance was considered negligible.
Measurement of Formaldehyde in Fish Muscle Using TCA Extraction and the Nash Reagent
Authors: Castell C. H. , Smith Barbara
Published: April 2011

The use of the Nash test, in conjunction with TCA extraction, for measuring formaldehyde in fish muscle was made more quantitative. This was done by means of a "recovery factor" which took into consideration the percent of formaldehyde added to the muscle extracted by the TCA solution. The average recovery from 15 different samples of cod muscle was 51.3% with an SD of 5.6. Because of differences between species in capacity to bind formaldehyde, it would appear that a different "recovery factor" may be required for each species of fish. As heating muscle increases its ability to bind formaldehyde, recovery factors developed for use with raw muscle are not applicable to the same muscle after it has been cooked. The percentage of added formaldehyde that was recovered varied with variations in the procedures used in preparing the muscle, making the extract, and carrying out the Nash test.
Effects of Handling on Oxygen Requirements of American Shad (Alosa sapidissima)
Authors: Chittenden Jr. Mark E.
Published: April 2011

Oxygen tolerance was determined 0.25, 3, and 24 hr after introducing young American shad (Alosa sapidissima) to washtubs 7, 4, 2, 5, 2, and 2 days after previous disturbance in the holding tank. Dissolved oxygen at equilibrium loss and death varied from 1.1 to 8.0 and 0.9 to 5.7 mg/liter, respectively; and mean oxygen levels at equilibrium loss and death in the 3-hr × 2-day tests were 1.5–3 times higher than in any other handling combination. Present evidence indicates that the effects of handling American shad vary, with the intensity of excitement generated by handling seeming to determine whether the fish lives, dies immediately, or dies later. This phenomenon is probably responsible for difficulty in transporting and marking this species and for conflicting reports on oxygen requirements and salinity and low temperature tolerance. Mean oxygen levels with 99% confidence limits at equilibrium loss and death of unexcited individuals were 1.62 ± 0.13 and 1.28 ± 0.19 mg/liter, respectively. Virtually no individuals lost equilibrium or died until oxygen declined to 2.56 and 1.92 mg/liter, respectively. Nearly all lost equilibrium or died at 0.68 and 0.64 mg/liter, respectively. Field and laboratory evidence suggests that minimum daily oxygen levels of 2.5–3.0 mg/liter permit migration through polluted areas, but 4.0 mg/liter appears necessary in spawning areas.
Seasonal and Local Variations in Odd-Chain Fatty Acid Levels in Nova Scotian Rainbow Smelt (Osmerus mordax)
Authors: Addison R. F. , Ackman R. G. , Hingley J.
Published: April 2011

Odd-chain fatty acid (OCFA) levels in rainbow smelt (Osmerus mordax) from Jeddore Harbour, N.S., showed a pronounced seasonal variation during the period from spring 1969 to fall 1970, reaching a maximum of 20% total fatty acids in the January–March period, and falling to a minimum of approximately 2% total fatty acids in summer and fall. The variation appeared to be general, and occurred in all OCFAs. Analysis of smelt stomach contents suggested that OCFAs originated in the diet. Smelt caught in inlets adjacent to Jeddore Harbour showed no unusual accumulation of OCFAs in January, 1970.
Lampetra pacifica, a New Nonparasitic Species of Lamprey (Petromyzontidae) from Oregon and California
Authors: Vladykov V. D.
Published: April 2011

A new nonparasitic species of Petromyzontidae, Lampetra pacifica, from streams of Oregon and California is described and illustrated. This species is distinguishable from Lampetra richardsoni, its nearest relative, by fewer myomeres, body proportions, pronounced pigmentation inside the buccal cavity, patterns of pigmentation of the head and tail, and geographical distribution. The description is based on an examination of 233 specimens (43 transformed individuals and 190 ammocoetes).
Intestinal Helminth Parasites of Northern Sand Lance (Ammodytes dubius)
Authors: Scott J. S.
Published: April 2011

Six species of helminth parasite were found on examination of intestines of 438 specimens of northern sand lance (Ammodytes dubius) from various areas of the Nova Scotia Banks. They were: Derogenes varicus, Brachyphallus crenatus, Lecithaster gibbosus, Bothriocephalus scorpii, Contracaecum aduncum, and a cestode (tetraphyllid) larva. Intensity of infestation was low and incidence low to moderate, with little difference between areas. Parasite species composition in A. dubius was similar to that of A. marinus, its European counterpart, but unlike that of A. americanus, the neighboring species to A. dubius in the northwest Atlantic.
Effects of a 12-hr and 25-day Exposure to Kraft Pulp Mill Effluent on the Blood and Tissues of Juvenile Coho Salmon (Oncorhynchus kisutch)
Authors: McLeay D. J.
Published: April 2011

Red blood cell counts and hematocrits of juvenile coho salmon were unaltered by 12-hr exposure to neutralized kraft pulp mill effluent, although hematocrits were decreased by exposure for 25 days. The number of circulating immature erythrocytes increased in effluent-exposed fish in both the 12-hr and 25-day exposures. The number of circulating small lymphocytes decreased markedly after 12-hr exposure. However, following the prolonged exposure, the number of small lymphocytes returned to normal, while the number of circulating neutrophils increased.The level of plasma glucose increased in fish exposed to effluent for 12 hr, and decreased in fish exposed for 25 days. Liver glycogen was not altered significantly during either exposure period.No pathological changes attributable to exposure to kraft pulp mill effluent were observed in the tissues examined, including the spleen, kidney, gill, interrenal gland, skin epithelium, and thyroid gland.Results are discussed in terms of a stress response.
Preparation and Properties of 3-Trifluoromethyl-4-Aminophenol
Authors: Lech John J.
Published: April 2011

This note describes a method for the preparation of 3-trifluoromethyl-4-aminophenol (RTFM), a metabolite of 3-trifluoromethyl-4-nitrophenol (TFM), and some of its physical-chemical properties, including infrared spectrum, pKa, and gas chromatography.
Uteriporus vulgaris Bergendal, 1890, A Marine Triclad New to North America
Authors: Tomkiewicz Warren , Ball Ian R.
Published: April 2011

Uteriporus vulgaris Bergendal, 1890, a marine triclad of the family Uteriporidae, is recorded from New Brunswick and the Gaspé coast, Quebec. These are the first records of this species, genus, and family in North America. A brief description of the material is given.
Identification of the Constituents of Kraft Pulping Effluent that Are Toxic to Juvenile Coho Salmon (Oncorhynchus kisutch)
Authors: Leach J. M. , Thakore A. N.
Published: April 2011

The nonvolatile constituents that are acutely toxic to juvenile coho salmon (Oncorhynchus kistuch) have been fully identified in a kraft pulping effluent derived from Douglas fir and western hemlock. Toxicity and material balances were maintained through out a fractionation procedure leading to isolation of the toxic factors.Over 80% of the toxicity was caused by three resin acid soaps: sodium isopimarate (55%), sodium abietate (22%), and sodium dehydroabietate (5%). The remaining toxicity (18%) was contributed by sodium salts of the unsaturated fatty acids: palmitoleic, oleic, linoleic, and linolenic.
An Outbreak of Redmouth Disease in Rainbow Trout (Salmo gairdneri) in Saskatchewan
Authors: Wobeser G.
Published: April 2011

During 1972 an outbreak of disease due to the "RM bacterium" occurred in caged rainbow trout (Salmo gairdneri) in a southern Saskatchewan lake. The mortality rate was approximately 1% of the population per week. Histopathologic lesions involved primarily the hematopoietic and reticuloendothelial systems. It is postulated that the disease was introduced with shipments of trout imported from Idaho shortly before the outbreak.
Uptake of Mercury by Caged Rainbow Trout (Salmo gairdneri) in the South Saskatchewan River
Authors: Uthe J. F. , Atton F. M. , Royer L. M.
Published: April 2011

Rainbow trout (Salmo gairdneri) were held in cages in the South Saskatchewan River to assess mercury uptake following curtailment of mercury discharges to the river. There was a rapid uptake of mercury by the fish during the first warm summer period (1970) with much less uptake during the rest of the year. A second summer experiment (1971) produced no significantly different results suggesting that a long-term contamination exists within this river system. Analyses showed that the bulk of mercury present in the fish carcasses was present as methylmercury.
Steam Distillation: A Simple Technique for Recovery of Petroleum Hydrocarbons from Tainted Fish
Authors: Ackman R. G. , Noble D.
Published: April 2011

Simple steam distillation was found to be efficacious for isolation of hydrocarbons from contaminated whitefish. Gas–liquid chromatography on support-coated open-tubular Apiezon-L columns demonstrated that hydrocarbons recovered from the tainted fish had a composition pattern qualitatively similar in detail to that from a sample of diesel oil suspected as the source of contamination.
The Species of Lepeophtheirus (CopepodarCaligidae) from Fishes of British Columbia
Authors: Kabata Z.
Published: April 2011

Description of, and keys to, 10 species of Lepeophtheirus (Copepoda:Caligidae), parasitic on fishes of British Columbia, are given. Diagnostic value of different morphological details is discussed. Nine of the species included were previously known (L. bifidus, L. breviventris, L. hospitalis, L. nanaimoensis, L. parvicruris, L. parviventris, L. paulus, L. pravipes, and L. salmonis) and one is described for the first time (L. oblitus).
Risk of Epibenthic Prey to Predation by Rainbow Trout (Salmo gairdneri)
Authors: Ware D. M.
Published: April 2011

A model is developed to describe the risk of aquatic prey to visual predators in general, and is evaluated with particular reference to rainbow trout (Salmo gairdneri). The equation system uses several principles of visual mechanics to determine predation rates and therefore requires statistics on the physical properties of the food resource, besides the visual acuity and other searching constraints of the predator.Application of the model to an independent set of field data accounted for 47% of the seasonal variation in the occurrence of four benthic invertebrate prey in the diet of trout from Marion Lake, B.C. Considerably better agreement — 70% of the variation — was obtained using a three prey system. Sequential comparisons between the predicted and observed pattern of predation suggest that prey activity, prey exposure, prey density, and prey size are four of the major determinants of prey risk in benthic food chains.
Orientation of Lobsters (Homarus americanus) to Odor
Authors: McLeese D. W.
Published: April 2011

Lobsters walk upstream toward the source of odor carried by a water current. They do not orientate when odor is distributed uniformly in the water. They follow odor trails in the absence of water current. Orientation appears to result from differential stimulation of bilateral chemoreceptors, the animal turning or moving toward the side of maximum stimulation.
Northern Range Extension and Probable Spawning of Gaspereau (Alosa pseudoharengus) in the Newfoundland Area
Authors: Winters G. H. , Moores J. A. , Chaulk R.
Published: April 2011

A single specimen of gaspereau, Alosa pseudoharengus (Wilson 1811), was taken near Paquet in northeastern Newfoundland. This is the first record of gaspereau from eastern Newfoundland and extends the northern range of the species in the western Atlantic. Spawning of gaspereau in Newfoundland rivers is also indicated.
Addendum: Mercury Removal from Fish Protein Concentrate
Authors: Regier L. W.
Published: April 2011

not available
Experimental Approaches to Limnology — An Overview
Authors: Schindler D. W.
Published: April 2011

not available
An Estimate of Energy Expenditure by Rainbow Trout (Salmo gairdneri) in a Small Mountain Stream
Authors: Feldmeth C. Robert , Jenkins Jr. Thomas M.
Published: April 2011

A method is presented which estimates energy expended by rainbow trout (Salmo gairdneri) in a natural stream habitat. Swimming speeds were determined by counting caudal fin beat frequency in the field. Published data on metabolic rates estimated in a water tunnel respirometer were then used to calculate energy expenditure.Swimming speeds and hence energy expenditure did not vary statistically for time of day or night (overall means: swimming speed, 16.1 cm/sec; energy expenditure, 736.5 cal/kg per hour). Our calculations indicate that swimming at 16 cm/sec would cost a 100-g rainbow trout 53 cal/hr at 15 C, and about 0.48 g (live weight) of natural food per 6 hr would be needed to offset the cost of swimming.
Taxonomic Status of Homoiotes palliata Wilson, 1905 (Copepoda: Caligidae)
Authors: Kabata Z.
Published: April 2011

Type material of Homoiotes palliata was examined and found to consist of a mixture of three species of Lepeophtheirus (L. pravipes, L. breviventris, and L. bifidus), all well established in the literature. It is suggested that H. palliata should be rejected as a taxon in the interest of nomenclatural stability. An approach to the International Commission on Zoological Nomenclature is being made, with this action in view.
Scientific Advice to Fisheries Bodies
Authors: Lucas C. E.
Published: April 2011

New fisheries require immediate order-of-magnitude estimates of potential sustainable yield, obtainable from echosounder surveys, catches of eggs and larvae, or even from primary productivity. As fishing develops more precise estimates are needed based on catch, effort, size and age composition, and the application of a suitable production model. Predicted levels of sustainable yield must then be checked against the performance of the fishery, and eventually the effects of environmental variability must be brought into a predictive equation.Systems for providing scientific advice by international working parties have been evolved in the more mature regional bodies, and are being adapted to the circumstances of the newer ones. Requirements are that their conclusions and predictions should be timely and expressed as simply as possible, and made fully available to all countries concerned. Neutrality and credibility are vital.These requirements of the scientists, in their international capacity, imply responsibilities for the Commissions to secure the best available scientists and a timely production of data by member countries, and to take timely decisions in the light of the evidence and predictions available.In the newer Commissions, and for fisheries where no regulatory body exists and scientists are few and inexperienced in collaborating internationally, aid on a broad scale is essential. This aid must come ultimately from the developed countries, sometimes directly and sometimes indirectly, via the regional or global body of which they are members. FAO and its COFI have a major role to play here; they, like the regional bodies, must be provided with funds for the requisite central staff, support services and facilities, and for mounting the necessary international working party meetings.The Department of Fisheries of FAO with its associated regional bodies is in a unique position to correlate fishery experience from different parts of the world, and to disseminate it wherever needed.
Development and Present Status of Bottomfish Resources in the Bering Sea
Authors: Pruter A. T.
Published: April 2011

Fisheries for bottomfish in the Bering Sea are largely a post-second world war development, with landings having increased from 13,000 metric tons in 1954 to an estimated 2 million metric tons in 1971. Most of the harvest is off Alaska in the southeastern sector of the Bering Sea, where conditions are most favorable for development of resources and fisheries. In 1970 and 1971, Japan accounted for approximately 84% and the USSR 15% of the combined harvest by all nations. South Korea, United States, and Canada took the remaining 1% of the harvest. Initial target of the fisheries of Japan and USSR was yellowfin sole. Yields of yellowfin sole were not sustained and Japan shifted attention to Alaska pollock. Production of Alaska pollock in 1970 from the North Pacific (about half is from the Bering Sea) was tied with Atlantic cod for second place in worldwide landings of a single species.Analysis of condition of resources is handicapped by unavailability of adequate statistics for earlier years of the fishery. Even for those participants who provided detailed statistics, information is usually lacking on quantities offish discarded, and changes in fishing gear and fishing tactics that need to be corrected for in assessing the condition of stocks. There is no institutional mechanism for Bering Sea or the North Pacific that makes it mandatory for all nations to provide common and comprehensive statistics on their fisheries and to undertake joint management.Consideration of available data suggests that the pulse nature of the Bering Sea fisheries resulted in the depletion of several important resources. Yellowfin sole were overfished during the early period of the fishery. Although the picture is far from clear for other species, the Pacific Ocean perch, blackcod, and shrimp resources also appear to have been overfished at least on certain important grounds within the Bering Sea. The chronology of Japan’s fishery for herring suggests the initial exploitation of the stock in the western Bering Sea off Asia may have been intense enough to deplete that resource. Although there is yet no indication of depletion of Alaska pollock, the great increase in harvest of that species, coupled with reliance on a few year classes to support the fishery, should serve as a warning against further uncontrolled increases in fishing.
Behavioral and Developmental Plasticity of Buoyancy in the Longnose, Rhinichthys cataractae, and Blacknose, R. atratulus (Cyprinidae) Dace
Authors: Gee John H.
Published: April 2011

The hypothesis that developmental plasticity contributes to variation in swimbladder length, volume, weight of tissue, and buoyancy was examined in two species of dace. At both maximum and minimum buoyancy attained dace reared in still water to adult size possessed swimbladders of a greater length, volume, and weight of tissue than those reared in current. Such developmental plasticity affected the range over which buoyancy could be adjusted (behavioral plasticity). Those reared in still water attained a more buoyant condition than those reared in current while the latter attained a greater degree of negative buoyancy.
A Method of Lipid Extraction Suitable for Use With an Electron Capture Detector
Authors: Hurst R. E.
Published: April 2011

A method of extracting oil is described in which ether is used as the lipophylic solvent in a monophase system. The method is as effective as the Bligh and Dyer method of extraction and avoids the use of chloroform, which interferes when gas chromatography is used with electron capture detection for analysis of the volatiles.
Sex Ratios and Lengths of Adult Sea Lampreys (Petromyzon marinus) from a Lake Ontario Tributary
Authors: Potter I. C. , Beamish F. W. H. , Johnson B. G. H.
Published: April 2011

The mean lengths of adult males and females of the sea lamprey (Petromyzon marinus) migrating into the Humber River from Lake Ontario in each of the years 1968–1972 varied little, and were similar to those found by other workers in recently established populations in the upper lakes. In contrast, the ratio of males to females, which lay within the narrow range of 1:1 to 1.26:1, was similar to those reported for long-established populations.
Abundance and Life History of Mysis relicta in the St. Lawrence Great Lakes
Authors: Carpenter G. F. , Mansey E. L. , Watson N. H. F.
Published: April 2011

In sampling on lakes Ontario, Erie, and Superior during three cruises from spring to fall, and on Lake Huron during eight cruises, Mysis relicta was generally not taken or not abundant in waters less than 25 m in depth. Its abundance appeared to increase with depth at least up to 200 m. Populations appeared to be concentrated in waters 125–200 m deep during summer and more dispersed during spring and fall. Highest numbers were found in Lake Superior, followed by lakes Ontario and Huron. A small localized population was found in the deep eastern part of Lake Erie.Size-frequency distributions from the various cruises on lakes Superior, Huron, and Ontario indicated differences in life cycles of the mysid in the three lakes. In Lake Superior there was one major period of recruitment, from February to July, and the generation time appeared to be 2 yr. In lakes Huron and Ontario recruitment appeared to occur from February to August and to be separated into a winter and a summer period; each of the generations appeared to mature in 18 mo.
A Simple Apparatus for Metering Volatile Liquids into Water
Authors: Benville Jr. Pete E. , Korn Sid
Published: April 2011

A metering device was developed to introduce benzene, toluene, xylene, and 1,2,4 trimethylbenzene vapors into water using air as a carrier gas. Setting the carrier gas flows for the respective aromatics at 10, 25, 120, and 500 cm3/min for 2 h resulted in concentrations of 8.2, 13.0, 12.0, and 7.2 μl/liter, respectively, in 4 liters of water. The aromatic concentrations were maintained in a static system by bubbling air through the water, and in a continuous flow system by replenishing the water. In static systems the respective aromatic concentrations were maintained for 4 days within the ranges of 13–14, 5.1–7.0, 0.40–0.50, and 0.018–0.028 μl/liter by bubbling the aromatics into the water at 5 cm3/min and independently aerating the water at 100 cm3/min. In a 14-day continuous flow system benzene concentrations ranged from 2.1–2.8 μl/liter when benzene was bubbling at 23 cm3/min and water was flowing at 1.8 liters/min.
Feeding Activity and Rates of Digestion of Northern Squawfish (Ptychocheilus oregonensis)
Authors: Steigenberger Lance W. , Larkin P. A.
Published: April 2011

Trapnet catches of northern squawfish (Ptychocheilus oregonensis) at Griffen and Cultus lakes, British Columbia, indicated peak activity and feeding in the twilight and dark hours. At Griffen Lake, squawfish force-fed 2.0 g of redside shiner (Richardsonius balteatus), and held at 17–20 C, digested at a rate of roughly 14%/h. At Cultus Lake, squawfish trapped during the peak of feeding activity, and held at 10–12 C, were sacrificed at 6-h intervals, and showed a digestion rate of sockeye salmon (Oncorhynchus nerka) smolts of 14%/h. Larger fish ate larger volumes of food. Regression techniques are not completely adequate for describing the course of digestion, which apparently involves an initial period of retention of food, followed by a fairly rapid evacuation of most of the ingested material. Most fish cleared their stomach contents in 24 h, and one half had done so between 12 and 18 h. In the laboratory, squawfish force-fed rainbow trout (Salmo gairdneri) had rates of digestion which increased with temperature, from about 5%/h at 4–6 C, to 40–50%/h at 24 C. Larger weights of food were digested at slower rates, but there were no consistent differences in rate of digestion by different sizes of squawfish.The rates of digestion are higher than those reported for various predatory European fishes.
Duration of Toxicity Tests for Establishing "No Effect" Concentrations for Copper with Brook Trout (Salvelinus fontinalis)
Authors: McKim James M. , Benoit Duane A.
Published: April 2011

Exposure of brook trout (Salvelinus fontinalis) to sublethal concentrations of copper from yearlings through spawning to 3-mo juveniles was found sufficient to establish a "no effect" concentration. No adverse effects were found on survival, growth, or reproductive capacity of trout exposed in a second generation from egg through spawning to copper concentrations (about 9.4, 6.1, and 4.5 μg/liter) which had caused no adverse effects on their parents when exposed to similar concentrations from yearlings to spawning. Nor were any adverse effects found on survival or growth of their offspring when exposed to the same concentrations from hatching to age 90 days. Tissue residue analyses indicated no copper accumulation in gill, liver, kidney, or muscle of either first- or second-generation trout exposed to the various copper concentrations, and residues in unfertilized eggs from exposed females were similar to those in females not exposed to added copper.
Factors Mediating Interspecific Aggregation of Tubificid Oligochaetes
Authors: Brinkhurst R. O.
Published: April 2011

Tubifex tubifex and Limnodrilus hoffmeisteri are both attracted to the feces of T. tubifex rather than to those of L. hoffmeisteri or a control sediment. This substantiates the hypothesis that lowered respiration and increased growth caused by mixing the two species could be due to an increase in time spent burrowing, rather than feeding, when isolated species are removed from their preferred food, the feces of another species of worm. It also helps explain the inter- and intraspecific clumping that characterizes their normal distribution.
Abundance and Potential Pathology of Parasites Infecting Salmonids in Canadian Maritime Hatcheries
Authors: Hare G. M. , Frantsi C.
Published: April 2011

Seventeen parasite species (3 protozoans, 11 helminths, 2 arthropods, and 1 mollusc) were collected from 317 Atlantic salmon (Salmo salar), 207 brook trout (Salvelinus fontinalis), and 34 rainbow trout (Salmo gairdneri) in the 13 Canadian Maritime hatcheries during 1972. Four parasites, Camallanus oxycephalus, Pomphorhynchus bulbocolli, Hydrachna sp., and a glochidium, were recorded from Atlantic salmon for the first time. Incidence and intensity of infection were high for Trichophyra piscium, Diplostomulum spathaceum, and glochidia infecting salmon and for Acanthocephalus lateralis and Salmincola edwardsii infecting brook trout. Infection intensity of Apophallus imperator, D. spathaceum, S. edwardsii, and glochidia increased with host age. Apophallus imperator and S. edwardsii were host specific to brook trout and the glochidium was host specific to salmon. Sterliadochona tenuissima and A. lateralis were more abundant in brook trout than in salmon. Pathology was associated with infections of Hexamita salmonis, D. spathaceum, A. lateralis, and S. edwardsii.
Surfacing on Ice of Frozen-In Marine Bottom Materials
Authors: Medcof J. C. , Thomas M. L. H.
Published: April 2011

In late winter and early spring, benthic materials have been observed in patches (maximum size 400 m × 10 m) on the surface of thick fast ice. They parallel the shores of estuaries and are commonest in the southern Gulf of St. Lawrence. Materials in the patches are often in strikingly natural postures and include layers of bottom sediment and plants and animals (eelgrass, shellfish [infauna and epifauna] starfish, flounders, and sticklebacks). Apparently these are frozen to the lower surface of the ice in early winter at low tides, when ice comes in direct contact with them. When the tide rises, the ice floats and raises frozen-on materials with it. Thereafter, the floating ice is thickened by freezing of water to its lower surface, and the bottom materials are thus frozen in between two layers of ice. At the same time the ice above the frozen-in materials is thinned by ablation (sublimation and melting) at its upper surface. Eventually the benthic materials are exposed on the surface of the ice. Allied phenomena have been observed in the Bay of Fundy region. Antarctica is the only other place where this has been reported to occur regularly. These phenomena and conditions favoring their occurrence in the two areas are compared.
A Semiautomatic Release Gear for Grabs and Corers
Authors: Burton William
Published: April 2011

A semiautomatic release gear may be attached to grabs and corers. It eliminates the need for a messenger, and improves efficiency under drifting conditions.
Descriptions of Copepodite Stages of Chiridius gracilis Farran 1908 (Crustacea: Copepoda)
Authors: Maclellan Delphine C. , Shih Chang-tai
Published: April 2011

On the basis of specimens taken from plankton samples, all copepodite stages of Chiridius gracilis are described and illustrated. The first thoracic somite is fused with the cephalosome in adults, but an incomplete suture exists between these body parts in cope-podites IV and V. The metasomal process, a prominent character of this species, appears as a small blunt process as early as copepodite I and becomes fully developed by copepodite IV. Segmentation of mouthparts is complete by copepodite IV but full setation is not acquired until the adult stage. The mandible, maxillule, and maxilla degenerate in the adult male. Segmentation and setation of swimming legs are complete in copepodite V in the female and in the adult male.
Genetic Differences in Retention of Swimbladder Gas Between Two Populations of Lake Trout (Salvelinus namaycush)
Authors: Ihssen P. , Tait J. S.
Published: April 2011

Lake trout (Salvelinus namaycush) derived from two populations differed in retention of swimbladder gas. The two reciprocal interpopulation crosses were intermediate to the parent populations. The two F1 hybrids obtained by crossing fish from each lake trout population with brook trout (S. fontinalis) were also found different in retention. Gas retention was correlated with depth distribution of the parent populations, high retention being associated with deeper distribution.
Taxonomic Status of the Salvelinus alpinus Complex
Authors: Qadri S. U.
Published: April 2011

Minor differences in osteology and morphology were observed in the eastern North American species of charrs Salvelinus aureolus (Sunapee), S. marstoni (Quebec red), and S. oquassa (blueback). The coefficient of difference values, which determine the degree of overlap were lower than 1.28 for the total numbers of vertebrae, ribs, epineurals, gill rakers, branchiostegals, pores on the lateral line scales, and also for many morphological characters suggesting that the three chars are conspecific and should by synonymized as S. alpinus oquassa.
Growth and Survival of Haddock (Melanogrammus aeglefinus) Larvae in Relation to Planktonic Prey Concentration
Authors: Laurence Geoffrey C.
Published: April 2011

When newly hatched haddock (Melanogrammus aeglefinus) larvae were fed zooplankters at nominal rates of 0.5, 1.0, and 3.0/ml in the laboratory at 7 C, they grew at similar rates. After 6 wk, they averaged 8.7, 10.0, and 11.2 mm in standard length and 810, 1300, and 1728 μg in dry weight, and had condition factors of 1.25, 1.22, and 1.32. When fed at 0.1 and 0.01 plankters/ml, all larvae died in 3 and 2 wk; at 0.5-3.0 plankters/ml, daily instantaneous mortality coefficients were 0.06–0.02 during 6 wk. Larvae began feeding 2 days after hatching, and the point of no return after they were deprived of food was 6 days after hatching, yolk absorption being completed on day 6 or 7. All larvae deprived of food until 8 and 10 days after hatching, although initiating feeding, did not survive another 4 days. Prey concentration also influenced delayed feeding with greater percentages of larvae able to initiate feeding at higher plankton levels on the point-of-no-return day.
Relative Importance of Additive Genetic and Maternal Sources of Variation in Early Survival of Young Splake Hybrids (Salvelinus fontinalis × S. namaycush)
Authors: Ayles G. Burton
Published: April 2011

Additive genetic and maternal effects of survival of uneyed eggs, eyed eggs, and alevins were determined from five series of matings within a splake brood stock. Average values for family h2 (heritability) and family m (maternal variance/total variance) were estimated. There were additive genetic effects in alevin survival (h2 =.41 ±.18) but not in uneyed or eyed egg survival. Maternal effects were greatest within the uneyed stage (m =.78 ±.22), decreased during the eyed egg stage (m =.68 ±.24), and were least within the alevin stage (.40 ±.19). The additive genetic effect on alevin survival was attributable to genetic differences in the resistance of young splake to blue sac disease (h2 =.76 ±.28).
First Record of the American Shad (Alosa sapidissima) from Labrador Waters
Authors: Hare G. M. , Murphy H. P.
Published: April 2011

A single specimen of American shad (Alosa sapidissima) was captured in the Sand Hill River, southeastern coastal Labrador. The capture represented the first confirmed record of shad from Labrador and the most northerly record of this species.
Coliform Flora of Migrating Sockeye Salmon (Oncorhynchus nerka)
Authors: Strasdine G. A. , Dubetz Lyn
Published: April 2011

The coliform flora of migrating sockeye salmon (Oncorhynchus nerka) was examined at two marine and one freshwater location. Enterobacter species accounted for approximately 50% of all isolates; the remaining isolates were divided almost equally between Citrobacter and Klebsiella types.
Lipids of Zooplankton from Bute Inlet, British Columbia
Authors: Lee Richard F.
Published: April 2011

Seventeen species of zooplankton representing four phyla were collected from Bute Inlet, one of the deep inlets (650 m) in British Columbia. Using lipid analysis and starvation studies, the zooplankton were divided into two categories based on whether the level of storage lipid was high or low. The polychaetaes, chaetognaths, and one of the ctenophores (Pleurobrachia pileus) were characterized by little storage lipid (neutral lipid only 7–10% of the lipid). It is assumed that these species transfer most new organic matter into new tissue rather than storage lipid. The copepods, Calanus plumchrus, Eucalanus bungi, Gaetanus columbiae, and Heterorhadus tanneri, were all characterized by high levels of storage lipid (between 53 and 90% of the lipid) and, except for Eucalanus, these consisted mainly of wax esters. The remaining zooplankters (ostracods, pteropods, euphausiids, amphipods, and decapods), except for the ctenophore, Beroe cucumis, stored primarily triglycerides. In all species examined, except B. cucumis, five fatty acids, 16:0, 16:1, 18:1, 20:5, and 22:6, accounted for over 90% of the total phospholipid fatty acid complement. Polyunsaturated C16 and C18 acids, which are common in phytoplankton, were absent or present in trace amounts in phospholipids but were abundant in the neutral lipids of herbivorous zooplankton. The wax esters of G. columbiae and B. cucumis had high levels of 16:0, 20:1, and 22:1 alcohols, whereas C. plumchrus had only 20:1 and 22:1 alcohols as major components.
Mouth and Mode of Feeding of Caligidae (Copepoda), Parasites of Fishes, as Determined by Light and Scanning Electron Microscopy
Authors: Kabata Z.
Published: April 2011

The structure of the caligid mouth tube is examined by light and scanning electron microscopy in examples of Caligus curtus, C. clemensi, and Lepeophtheirus salmonis. Special attention is directed to the intrinsic musculature of the labrum. A new masticatory apparatus is described, consisting of a divided dentiferous bar at the tip of the labium and referred to as a strigil.A new concept of the mode of feeding is presented. The tissues of the fish are scraped off by movements of the strigil and the debris is then picked up by the mandibles which initiate its passage into the buccal cavity. Its transport is assisted by contractions of labral musculature, capable of creating a propelling, peristaltic wave.
Planned Transdisciplinary Approaches: Renewable Resources and the Natural Environment, Particularly Fisheries
Authors: Regier Henry A. , Bishop Patrick L. , Rapport David J.
Published: April 2011

Ecologies who have long sought a larger role for their science and insights in the decision-making process now find that possibility open to them. But the recognition is dawning that traditional ecological concepts and methods arc seldom directly relevant to major problems with renewable resources and the natural environment. What is proposed as a partial framework for a more comprehensive, planned transdisciplinary approach is elaborated in some detail. Current issues with Canadian fisheries are used to relate the concepts to practical concerns.
Age Composition and Growth of Yellowtail Flounder (Limanda ferruginea) from the Grand Bank
Authors: Pitt T. K.
Published: April 2011

The commercial yellowtail flounder (Limanda ferruginea) fishery on the Grand Bank is comprised of fish age 4–12 with the main contribution from 6–8-yr-olds. Comparison of Grand Bank yellowtail with those reported for the Scotian Shelf indicates similar growth curves. The New England stocks are significantly larger at comparable age probably because of higher water temperatures.
Identification, Analysis, and Removal of Geosmin from Muddy-Flavored Trout
Authors: Yurkowski M. , Tabachek Jo-Anne L.
Published: April 2011

Geosmin has been isolated and identified, using gas-chromatographic, mass-spectrometric and organoleptic analysis, as the principal compound responsible for the muddy flavor in fish from various saline lakes in western Canada. A method for quantitative estimation of geosmin has been described and evaluated. Placing of muddy-flavored rainbow trout (Salmo gairdneri) in clean water resulted in reduction of flavor to the borderline level between 3 and 5 days, and of geosmin concentration from 1.1 to 0.3 μg/100 g of flesh in 14 days. The taste threshold level of geosmin was estimated to be 0.6 μg/100 g flesh.
Photochemical Dechlorination of Water Supply for Fish Tanks, with Commercial Water Sterilizers
Authors: Armstrong F. A. J. , Scott D. P.
Published: April 2011

Commercial mercury-lamp water sterilizers can be used for removal of free chlorine in water supplies, by photochemical action. The efficiency of removal decreases with increasing pH, but is little affected by temperature. It is greatest at low initial chlorine concentration. Equipment with either low or high pressure mercury vapor lamps may be used. Removal of 90% of free chlorine can be effected at about 13.0 liters min−1 with a sterilizer using eight low pressure lamps of 40 W, or at 50 liters min−1 or more with two 1200-W sterilizers with high pressure lamps in tandem. Treated water appears to be harmless to fish.
Observations On Subsurface Distributions Of Chlorophyll a And Phytoplankton Carbon In The Northeast Pacific Ocean
Authors: Hobson Louis A. , Ketcham Dawn E.
Published: April 2011

Measurements of subsurface concentrations of chlorophyll a and phytoplankton carbon were made between Vancouver Island and Hawaii during summer 1971. In general, chlorophyll a concentrations increased and concentrations of phytoplankton carbon decreased from 10 m to depths varying between 100 and 150 m. These distributions indicated that cellular contents of chlorophyll a increased as cells were exposed to diminishing daily irradiations. Daily compensation irradiations for net photosynthesis of subsurface phytoplankton in the northeast Pacific Ocean were estimated in summer 1973. Values ranged between 0.5 and 0.7 cal cm−2 but variability among replicates was large giving a range of 0 and 1.2 cal cm−2. It was not possible to correlate compensation irradiations with taxonomic composition of phytoplankton populations.
DDT and the Rugophilic Response of Settling Barnacles Balanus improvisus
Authors: Meith-Avčin N.
Published: April 2011

Treatment of glass settling plates with DDT generally resulted in lowered settlement densities of the cyprids of Balanus improvisus and lowered indices of preference for roughened surfaces, indicating that DDT interferes with the cyprids' rugophilic response pattern to settlement surfaces.
Effects of Thiourea Treatment on Sexually Maturing and Gonadectomized Male Sockeye Salmon (Oncorhynchus nerka)
Authors: McBride J. R. , Overbeeke A. P. van
Published: April 2011

Adult male sockeye salmon in the final stage of sexual maturation were treated with thiourea for periods of 7–14 wk. The treatment produced strong histological thyroid stimulation but no visible effect on spermatogenesis or development of secondary sexual characteristics. The drug did not affect the interrenal hypertrophy that commonly occurs in these salmon, but slightly inhibited the increase in thickness of the skin. Thiourea induced changes in the pars distalis of the pituitary gland, involving several cell-types, including retardation of gonadotrop development.In gonadectomized fish, thiourea affected neither the skin, nor the interrenal tissue. It caused a marked increase in the height of the thyroid epithelium, correlated with hypertrophy, degranulation, and some vacuolization of PAS-positive cells in the dorso-caudal area of the proximal pars distalis of the pituitary gland. Therefore, these last cells are considered thyrotrops.
Growth, Metabolism, and Optimal Swimming Speed of a Pelagic Fish
Authors: Ware D. M.
Published: April 2011

Ivlev’s (1960) study of young bleak (Alburnus alburnus) is reanalyzed to determine whether or not the routine swimming speeds of planktivorous fishes could have evolved to maximize some obvious measures of biological performance – namely the growth rate, the growth efficiency, or the growth efficiency arising from a particular food ration. Each criterion had a maximum value at a different swimming speed. But for bleak the observed speed of 107 m h−1 was closest to the one, 111 m h−1, which maximizes growth. The possible evolutionary significance of this finding is discussed.New calculations based on Ivlev’s work indicate that the field metabolism of young, actively growing fish may be closer to 3 times the standard metabolic rate, rather than the factor of 2 suggested by Winberg (1956).
Oxidative Deterioration of Canned Lake Whitefish (Coregonus clupeaformis) Treated with Antioxidants
Authors: Biggar C. A. , Eskin N. A. M. , Vaisey M. , Johnston B.
Published: April 2011

Lake whitefish (Coregonus clupeaformis) was canned with one of two antioxidant mixtures, AX1 (20% butylated hydroxyanisole, 20% butylated hydroxytoluene) or AX2 (10% butylated hydroxyanisole, 10% butylated hydroxytoluene, 6% citric acid, and 6% propyl gallate), and compared to untreated control samples. The flavor and quality of the fish were examined at intervals during 4 days of open refrigerated storage using sensory, chemical, and physical methods. Both thiobarbituric acid (TBA) values and the results of paired flavor comparisons by an eight-member trained sensory panel demonstrated that the greatest degree of oxidative deterioration was always associated with the untreated fish, while AX1-treated fish exhibited the least amount of "off-flavor" over the storage period. The relative degree of "off-flavor" as evaluated by the panelists tended to increase on storage; TBA values showed a linear relationship with time. Tristimulus readings using the Hunter Colorimeter showed a significant difference between the control sample and the two antioxidant-treated samples with respect to the pink color of freshly opened canned whitefish.
Otolith Age Validation of Greenland Halibut (Reinhardtius hippoglossoides)
Authors: Lear W. H. , Pitt T. K.
Published: April 2011

Length and age distribution, together with evidence indicating the annual formation of an opaque and translucent hyaline zone on the otoliths of Greenland halibut (Reinhardtius hippoglossoides), point to the validity of using otoliths in age determination. The high incidence of opaque zones during July–October suggests that these fish grew fastest during this period. Young fish appeared to have a longer annual growth period than the older specimens.
Biodegradation of Di-n-Butyl Phthalate and Di-2-Ethylhexyl Phthalate in Freshwater Hydrosoil
Authors: Johnson B. Thomas , Lulves William
Published: April 2011

The phthalic acid esters di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP) which are used as plasticizers and recovered in routine chemical analysis of freshwater fish, were incorporated into freshwater hydrosoil in the laboratory. Samples containing about 1 mg/liter of these two esters, 14C (carbonyl) labelled, were incubated aerobically and anaerobically for 1, 5, 7, 14, and 30 days. Differences in the rates and conditions of degradation of the two esters were marked. Under aerobiosis, 53% of the radio-labelled DBP was degraded within 24 h, and 98% within 5 days; DEHP, in contrast, was only 50% degraded after 14 days. Under anaerobiosis degradation of both esters was retarded. DBP was degraded only one-sixth as fast in hydrosoil overlayed with nitrogen whereas degradation of DEHP was not detected. Our evidence from both thin-layer chromatography and radiorespirometry suggests that the esters undergo decarboxylation after initial hydrolysis, probably to the 1,2-dihydroxybenzene molecule.
Fecundity Comparisons for Various Stocks of Lake Whitefish, Coregonus clupeaformis
Authors: Healey M. C. , Nicol C. W.
Published: April 2011

We found no significant differences in slope or intercept for the regression of loge fecundity on loge fork length among samples of whitefish from four lakes near Yellowknife in the Northwest Territories. The equation describing the relationship between fecundity and fork length for these populations was:[Formula: see text]Five other populations for which length–fecundity relationships could be calculated had length exponents ranging from 3.20 to 4.38, suggesting a nonlinear relationship between weight and fecundity. Six of the nine populations as well as four others for which limited data were available all had similar relative fecundities. Fish from Buck Lake in Alberta and from Lake Erie had high relative fecundities while fish from Great Slave Lake had low relative fecundity.