bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of National Quotas by the International Commission for the Northwest Atlantic Fisheries
Authors: Edelman M. S. , Dokuchaev I. I.
Published: April 2011

The Northwest Atlantic Ocean is one of the areas where fish stocks have been subjected to exceedingly high fishing pressure by many European and American countries, to the extent that some of them require strict control. International cooperation has been achieved through the International Commission for the Northwest Atlantic Fisheries (ICNAF). The Commission has applied conservation measures following scientific advice from various panels and committees, and stands as the first example of the application of national quotas for major exploited species.By 1967, increases in total catches in the ICNAF Area were accompanied by decreases in the catch per unit of effort, and it became apparent that regulations on mesh size were not sufficient to maintain the stocks. The Standing Committee on Regulatory Measures was created to consider alternative regulations, and the economic and administrative problems connected with them. A Committee on Research and Statistics was charged with preparation of scientific data on status of the stocks and measures necessary to maintain and restore them.As early as 1968, proposals were made to establish total catch quotas for principal species and to allocate these among the countries fishing. Adoption of this kind of regulation involved amendments to the Convention, and decisions were therefore difficult to achieve without a long and detailed study.At the 1969 meeting, many stocks had declined further and stricter quotas were applied. The Commission recommended changes in the Convention to allow regulations to be made on economic and technical as well as on scientific data; this was the first step on the way to fixing national quotas. The Standing Committee on Regulatory Measures recommended overall quotas for the principal species and that these quotas be shared among participating nations, taking into account interests of states with developing fisheries, states whose fleets are incapable of being diverted to other fisheries, special interests of coastal states, and historical landings. The weight to be given to these various factors was left for further negotiations.At the 1970 meeting, as only four member countries had ratified the agreements on national quotas, this problem remained unsolved. In 1971, despite further declines in catch and better research data, the Commission was still unable to agree on national quotas. But at an extraordinary meeting in January and February 1972, total quotas were established for herring in particular areas, and for national quotas. Thus for the first time in history national quotas were accepted by fishing countries. Later, overall and national quotas were recommended for the other principal species. It is hoped that this experience will be useful to other international bodies in resolving this complex problem.
Factor Analysis in Discriminating the Racial Origin of Sockeye Salmon (Oncorhynchus nerka)
Authors: Messinger H. B. , Bilton H. T.
Published: April 2011

A comparison was made between the procedure of factoring variables before using them in discriminant analysis and the usual procedure of using the original variables in discriminant analysis. The results indicated factoring seven scale measurements on sockeye salmon (Oncorhynchus nerka) with varimax rotation produced four new variables which gave more valid results in classifying sockeye salmon by area of origin than the original variables when discriminant functions were computed. Although the results on the basic data from which the functions were derived were not as good using the four factor scores as the seven original variables, the accuracy of classification was much more consistent in the test data with the factor scores. The loss in accuracy was at least [Formula: see text] times as great for functions based on the original variables as for ones based on factor scores. The errors in classifying fish to their individual places of origin were perhaps too large for the procedure to be useful in the field, but the accuracy of classification to the British Columbia or Alaska region was quite high.
Lepeophtheirus cuneifer sp. nov. (Copepoda: Caligidae), a Parasite of Fishes from the Pacific Coast of North America
Authors: Kabata Z.
Published: April 2011

Lepeophtheirus cuneifer sp. nov. (Copepoda: Caligidae) is described and illustrated. This copepod is a parasite of marine fishes off the coast of Alaska, its hosts including Raja binoculata and Hexagrammos lagocephalus. Other possible hosts are Leptocottus armatus and Theragra chalcogramma.
Growth and Survival of White Suckers (Catostomus commersoni) in an Acidified Lake
Authors: Beamish Richard J.
Published: April 2011

White suckers (Catostomus commersoni) in the acidic Lumsden Lake in 1967 and 1968 exhibited reduced annual growth followed by death. The reduced growth and death appeared directly related to the low pH and not to a shortage of food caused by the decreasing pH.
Daily Feeding Rates of Bluegill (Lepomis macrochirus) Determined by a Refined Radioisotope Method
Authors: Kolehmainen Seppo E.
Published: April 2011

The daily values of 137Cs intake by bluegill (Lepomis macrochirus) from a small impoundment receiving low-level radioactive effluents were used to calculate the daily feeding rates of the fish. The calculations of 137Cs intake, for a nonequilibrium state, were based on fish growth, the seasonal fluctuation of 137Cs concentration in fish, and the temperature-elimination rate relationship. The feeding rates were obtained by dividing the daily intake of 137Cs by the concentration of 137Cs in the diet. The daily meal of bluegill varied from 0.8% of body weight in February to 3.2% in June with an annual mean of 1.75%. There was a positive correlation (r2 = 0.805) between the daily meal and the daily temperature. The ecological growth efficiency was 4.2% during the period from April to October.
Effects of M.S. 222 Anesthetization on Temperature Selection in Lake Trout, Salvelinus namaycush
Authors: Goddard C. I. , Lilley J. W. , Tait J. S.
Published: April 2011

Yearling lake trout (Salvelinus namaycush) were anesthetized with a 150 ppm solution of M.S. 222 for 2 min at 10 C. When tested in a vertical temperature gradient, their behavior was abnormal for 5 days following anesthetization. Initially, they remained at the bottom of the gradient tank, as much as 63% of the time, and when they did swim up into the gradient, their temperature selection was much less precise than that of control fish. The percentage of fish on the bottom declined daily, and on the 6th day their temperature distribution did not differ from that of controls.
Interaction of Free Fatty Acids with Fish Muscle in Vitro
Authors: Childs E. A.
Published: April 2011

When fresh fish muscle (Ophiodon elongatus) was exposed to free fatty acids (safflower oil hydrolysate), the whole myofibril lost its suspensibility more readily than its component proteins lost their solubility. SDS-acrylamide gel electrophoresis indicated that tropomyosin was the most readily insolubilized protein. In the presence of 0.04% formaldehyde, effects of the free fatty acids were increased approximately threefold.
A Proposed Method Suitable for Large-Scale Surveys of Biomass in Lakes
Authors: Carpenter George F.
Published: April 2011

A method for studying plankton biomass by comparing the results between planktonnet hauls and an integrated water column sample is described. Filtering the planktonnet sample through glass-fiber filter papers would yield planktonnet phytoplankton plus zooplankton biomass. Filtering the integrator sample would yield total phytoplankton biomass. Sieving part of this sample would give direct estimates of net and nannophytoplankton which could be used in combination with the values of net plankton biomass to give estimates of total biomass and zooplankton biomass.Ash-free dry weight is recommended instead of dry weight biomass. The results are easy to produce, are comparable with other parameters such as particulate carbon and nitrogen, and are in units which may be used in the determination of trophic status or nutrient budgets for a lake.
Renal Tubular Morphology in the Channel Catfish (Ictalurus punctatus) Kidney
Authors: Kendall M. W. , Hinton D. E.
Published: April 2011

Kidneys of 50 channel catfish (Ictalurus punctatus) (25–30 cm long) obtained from a fish hatchery were subjected to light microscopic examination. All renal tubular segments generally found in freshwater teleost kidney were present. These included a ciliated neck segment, bisegmental proximal segment, ciliated intermediate segment, distal segment, and, in addition, collecting ducts.
Effects of Cold Shock on Vulnerability of Juvenile Channel Catfish (Ictalurus punctatus) and Largemouth Bass (Micropterus salmoides) to Predation
Authors: Coutant C. C. , Ducharme Jr. H. M. , Fisher J. R.
Published: April 2011

Acute cold stress caused increased predation on juvenile channel catfish (Ictalurus punctatus) and largemouth bass (Micropterus salmoides) by unstressed adult largemouth bass when temperature differentials were 9 and 7 C or more, respectively, (base temperatures 16 and 17 C). Predation rate tended to increase exponentially with increasing temperature differential. Catfish held 1 h in the cold water were only slightly less susceptible to predation than were others tested immediately after the temperature change.
Food of Shorthorn Sculpin, Myoxocephalus scorpius, in the Cumberland Sound Area of Baffin Island
Authors: Moore I. A. , Moore J. W.
Published: April 2011

One hundred shorthorn sculpins, Myoxocephalus scorpius, over 15 cm in length captured from June to October, 1972, in Cumberland Sound, Baffin Island, fed almost exclusively (90% by both numbers and dry weight) on the planktonic amphipods Pseudalibrotus glacialis and Parathemisto libellula. In contrast, 140 fish captured about the same times from nearby Pangnirtung Fjord fed heavily on the benthic gastropods Littorina saxatilis and Margarites umbilicalis (each 34% by numbers and 22% by weight) and the bivalve Modiolaria discors (16% by both). Drifting ice on Cumberland Sound probably reduced the level of illumination making the detection of benthic prey difficult and causing the sculpins in this area to feed entirely on the better illuminated, brightly colored plankton. At both localities, the most abundant species in the plankton and the epifauna were also the most frequently encountered in gut contents. On the other hand, coelenterates, planktonic gastropods, copepods, and infauna, all of which were abundant in the environment, were rarely eaten.
Simultaneous Measurements of Trimethylamine and Dimethylamine in Fish, and Their Use for Estimating Quality of Frozen-Stored Gadoid Fillets
Authors: Castell C. H. , Smith Barbara , Dyer W. J.
Published: April 2011

On the basis of some of the recent modifications of Dyer's colorimetric test for measuring trimethylamine (TMA) in fish, a procedure is described that gives both the TMA and the dimethylamine (DMA) contents. Measurements on 84 frozen-stored fillets of haddock, cod, pollock, cusk, and hake showed a correlation coefficient of 0.94 between DMA values obtained by the copper–dithiocarbamate test and those obtained by the picric acid procedure. The simultaneous measurements of TMA and DMA are useful in estimating the quality of frozen-stored gadoid fillets, the TMA value indicating the extent of microbial spoilage before the muscle was frozen and the DMA value the extent of deterioration through action of tissue enzymes during frozen storage.
Effects of Interactions of Irradiance, Daylength, and Temperature on Division Rates of Three Species of Marine Unicellular Algae
Authors: Hobson Louis A.
Published: April 2011

Rates of light-saturated division of Thalassiosira fluviatilis and Isochrysis sp., marine unicellular algae, were regulated by temperature and daylength at 25 C, and primarily by temperature at 20 C or less. The rates for Chroomonas salina appeared to be regulated by temperature and daylength at temperatures between 10 and 25 C, with maximum effects of daylength occurring at temperatures of 20 and 25 C. Physiological mechanisms through which temperature and daylength interact to regulate division rates of unicellular algae are discussed.
Infectious Pancreatic Necrosis Virus Occurrence at a Hatchery in Alberta
Authors: Yamamoto T.
Published: April 2011

The presence of infectious pancreatic necrosis (IPN) virus in brook (Salvelinus fontinalis) and rainbow (Salmo gairdneri) trout was identified and further investigated. A high incidence of virus was found by virological examination of kidney tissue from yearling and older trout. By comparison, brook trout had a much higher incidence of virus than rainbow trout.The virus was isolated most frequently from the kidneys of both species of trout. These findings indicate that the examinations of peritoneal washes and feces is not adequate for the detection of IPN carrier fish.
Portuguese and Japanese Oysters are the Same Species
Authors: Menzel R. W.
Published: April 2011

Indistinguishable prodissoconch and adult shells, ease of hybridization, and normal meiosis and mitosis in the hybrids support the contention that the Portuguese oyster Crassostrea angulata and the Japanese oyster C. gigas are the same species. By rules of priority the Portuguese is a subspecies of the Japanese oyster. Two hypotheses are given to explain the widely disjunct distribution, by both species arising from a common ancestor or by undocumented introduction. Both oysters are of considerable commercial importance and crossing the two should result in progeny that can be selected for superior commercial traits.
Effects of the Insecticide Carbaryl on Clams and Some Other Intertidal Mud Flat Animals
Authors: Armstrong David A. , Millemann Raymond E.
Published: April 2011

The insecticide carbaryl (Sevin) significantly reduced numbers of juvenile clams in plots treated with 2.3 and 4.6 kg (5 and 10 lb)/acre. Pooling of samples taken at 1, 2, 4, 15, and 30 days after treatment showed mean clam numbers per m2 in untreated and treated plots were 364, 283, and 224, respectively, the reductions from the controls being 22 and 38%. Clam species differed in susceptibility to carbaryl; for example, numbers of the gaper clam (Tresus capax) were reduced by 58 and 69% at the low and high application rates in relation to those from the control plots, and the bent-nosed clam (Macoma nasuta) by 9 and 28%. There was no reduction in numbers of polychaete and nemertean worms.A carbaryl application of 2.3 kg/acre was as effective in controlling ghost shrimp (Callianassa californiensis), an oyster pest, as 4.6 kg/acre. Signs of stress and numbers affected are given for other mud flat animals.
Preparation and Use of a Modified Protein Binder in the Fabrication of Feed for Post-Larval Aquacultural Animals
Authors: Groninger Jr. Herman S. , Miller Ruth
Published: April 2011

The laboratory preparation of a modified protein (acylated) binder is described. The important feature of this binder is that it enables a rapid and simply effected conversion of a liquid feed to a solid feed. A laboratory method is given for the fabrication of aquacultural feed using this modified binder. A typical feed that has been prepared with this binder has an elastic texture, resists fragmentation in water, and is readily acceptable to test animals.
Limnological Conditions in Five Small Oligotrophic Lakes in Terra Nova National Park, Newfoundland
Authors: Kerekes Joseph J.
Published: April 2011

Five oligotrophic lakes in Terra Nova National Park, Newfoundland, varying in mean depth (1.06–9.22 m), in water renewal rate (0.2–20.7 times per annum), in salinity (18.2–42.6 mg/liter), in total phosphorus (0.1–0.6 mg-at P/m3), and in chlorophyll a concentration (0.5–3.2 mg/m3), were investigated for 17 mo in 1969 and 1970. Hypolimnetic oxygen deficits ranged between 111 and 217 mg O2 per m2/day. Low levels of nutrients, reduced solar radiation, and low underwater light penetration, owing to excessive cloudiness and high water color, seriously limited planktonic primary production. The relation between primary production at optimum light, and water renewal per annum, appeared to be curvilinear when the rate of primary production began to decline above an optimum water renewal rate. The seasonal and annual variations in water color and salinity were dependent on the rate of water renewal, but other lakes on the catchment areas modified that relation. Winter road salting operations within the catchment area caused a considerable increase in salinity, total phosphorus concentration, and primary production in one lake. A new morphometric index which reflects the littoral effect on basin volume was proposed.
Phytoplankton Production in Char Lake, a Natural Polar Lake, and in Meretta Lake, a Polluted Polar Lake, Cornwallis Island, Northwest Territories
Authors: Kalff J. , Welch H. E.
Published: April 2011

Phytoplankton production of ultraoligotrophic Char Lake and polluted Meretta Lake Oat. 74°42′N; long. 94°50′W) were studied between 1969 and 1972. Phytoplankton production in Char Lake is approximately 4.1 g C m−2 yr−1, making it the most oligotrophic lake on record. Photosynthesis takes place virtually the whole 9 mo the sun comes above the horizon. Changes in depth of maximum photosynthesis, in efficiency of low light utilization, and in optimal light flux resulted in a much more constant production rate than suggested by the light input, which is importantly affected by amount of snow cover. Phytoplankton in nearby sewage-polluted Meretta Lake averages 11.3 g C m−2 yr−1, and chlorophyll concentrations are 20 times higher than in Char Lake. Nutrient deficiencies, especially of phosphorus, are almost certainly responsible for the low efficiency of light utilization and resulting low production in Char Lake. Benthic production is of major significance in both lakes.
Marion Lake (IBP) — from Bacteria to Fish
Authors: Hall Ken J. , Hyatt Kim D.
Published: April 2011

The microbial–detritus food chain in the sediment of Marion Lake, British Columbia, is an important pathway for the cycling of organic matter derived from both allochthonous (leaf litter) and autochthonous (phytoplankton, aquatic macrophytes, and benthic algae) sources. The activity of the sediment microbial community (approximately 109–1010 cells/g dry wt) as estimated by oxygen consumption and solute uptake is greatest during the summer months, when water temperatures are higher than 10 C. Solute uptake is also influenced by sediment depth, nutrient enrichment, sediment particle size, and oxygen concentration. Organic matter from natural sources such as algal excretion, interstitial water, and leaf detritus is complex and is not assimilated as rapidly as the simpler organic compounds.Rainbow trout (Salmo gairdneri) and kokanee (Oncorhynchus nerka) in Marion Lake are characterized by small average size and slow growth rates. Fish production, although highly variable, is at the low end of the range compared to other salmonid producing systems. These characteristics are related to the inefficiency of trout and kokanee in cropping the benthic food supply. Experiments with individual predators and their prey have identified the nature of many of the interactions controlling the availability of benthic prey to the predators. Construction of simulation models shows promise as a means to quantify the importance of such interactions.
A Digital Echo-Counting System Used in Determining Abundance of Freshwater Pelagic Fish in Relation to Depth
Authors: Kelso J. R. M. , Pickett E. E. , Dowd R. G.
Published: April 2011

The digital echo-counting system consisted of a 200 kHz echo-sounder, cathode-ray tube, preamplifier rectifier, and digital logic. Incoming signals were gated by delayed pulses of 6.6 msec duration to represent 5 m depth shells from 5 to 25 m depth. Response to density was linear. Acoustic estimates of density ranged from 19.3/10,000 m3 to 524.0/10,000m3 and trawl estimates of density ranged from 17.4/10,000m3 to 420.0/10,000m3. A high degree of correlation (0.94) existed between densities estimated acoustically and by midwater trawl. Species differences, smelt in Lake Erie, and alewife in Lake Ontario, did not seem to affect density estimates.
Functionality of Fish Muscle: Emulsification Capacity
Authors: Childs E. A.
Published: April 2011

The emulsification capacity of white muscle of Oregon groundfish was investigated — English sole, sand sole, petrale sole, lingcod, and orange rockfish emulsified 75–80 ml oil/g muscle. Little variation was found in the emulsifying capacity of samples from four catches spaced over a 3-mo period. Frozen storage (−40 C) caused no apparent decrease in emulsifying capacity even after 12 mo of storage. In vitro exposure to formaldehyde and Cu++ caused a decrease in emulsifying capacity, but Cu+ had no significant effect. The addition of 0.02% free fatty acid caused a > 20% increase in emulsifying capacity.
Influence of Salinity on Protein Requirements of Coho Salmon (Oncorhynchus kisutch) Smolts
Authors: Zeitoun Ibrahim H. , Ullrey Duane E. , Halver John E. , Tack Peter I. , Magee W. T.
Published: April 2011

Six purified diets ranging from 30 to 55% protein in 5% increments were fed for 10 wk to duplicate groups of coho salmon (Oncorhynchus kisutch) smolts maintained at 10 or 20‰ salinity. The data indicated that minimum protein requirements did not differ for fish at either salinity, and weight gain and protein retention levelled off after 40% protein in the diet was reached. Salinity had a minor effect on the criteria measured whereas the different dietary protein concentrations were of major consequence. The protein efficiency ratio (PER) of the casein diet containing 40% protein was 2.20 ± 0.11 whereas apparent net protein utilization (NPU) at the same level was 36.1 ± 1.8.
Primary Production in Relation to Temperature Structure, Biomass Concentration, and Light Conditions at an Inshore and Offshore Station in Lake Ontario
Authors: Stadelmann P. , Moore J. E. , Pickett E.
Published: April 2011

Annual primary production rates of 270 and 170 g C m−2 yr−1, respectively, were estimated for an inshore and offshore station in Lake Ontario using the in situ 14C technique. A lag in increase of both biomass and photosynthesis rate at the offshore station in early summer was attributed to deep vertical mixing.Production/biomass quotients were computed using different biomass parameters such as particulate organic carbon, nitrogen, and chlorophyll a. Carbon turnover rates of the seston on an areal basis (m2) were found to vary between 0.04–0.18 day−1 and 0.01–0.21 day−1 at the inshore and offshore station, respectively. Daily photosynthesis efficiency (energy fixed by photosynthesis/available energy) ranged from 0.1 to 1.8% at the two stations. Atypical photosynthesis–light intensity curves showed that algal populations behaved differently at different depths during the stratified period.
Mercury, DDT, Dieldrin, and PCB in Two Species of Odontoceti (Cetacea) from St. Lucia, Lesser Antilles
Authors: Gaskin D. E. , Smith G. J. D. , Arnold P. W. , Louisy M. V. , Frank R. , Holdrinet M. , McWade J. W.
Published: April 2011

Samples of blubber, muscle, liver, and kidney of short-finned pilot whale Globicephala macrorhyncha and long-snouted dolphin Stenella (longirostris ?) from waters adjacent to St. Lucia, Lesser Antilles, were analyzed for Hg, DDT, dieldrin, and PCB. Total Hg levels were high, ranging from 1.33 to 5.36 ppm in muscle (methylated fraction 42–100%), 2.28 to 14.00 ppm in kidney (methylated fraction about 14%), and 13.00 to 157.00 ppm in liver (methylated fraction 2–17%). ΣDDT in blubber ranged from 1.25 to 7.38 ppm, dieldrin in blubber from 0.007 to 0.04 ppm, and PCB in blubber from 0.69 to 5.00 ppm. The presence of the high Hg levels is attributed largely to natural sources, as the Lesser Antilles Island Arc is a site of intense cyclic tectonic activity. There may be some contribution from atmospheric sources. Both DDT and PCB could be largely the result of atmospheric transportation from higher Atantic latitudes, although local DDT spraying programs may have contributed. Certainly the circulation pattern in the Gulf of Mexico and Caribbean appears to rule out water-borne transport from the river systems of the Gulf States of the United States.
Short-Term Serum Cortisol Concentrations in Goldfish (Carassius auratus) Subjected to Serial Sampling and Restraint
Authors: Spieler Richard E.
Published: April 2011

Serum cortisol from serially sampled goldfish (Carassius auratus) did not demonstrate a stress-evoked increase (P >.05) until 10–22 min after initial capture. This response did not differ (P > 0.5) among fish sampled at the beginning, middle, and end of a 12-h light period.
Seasonal Variation of the Chlorophyll a:Pheopigment Ratio in the Gulf of St. Lawrence
Authors: Spence C. , Steven D. M.
Published: April 2011

Measurements of the chlorophyll a:pheopigment ratio from all parts of the Gulf of St. Lawrence showed a close relationship between changes in the ratio and the annual cycle of primary production. The chlorophyll a fraction was greatest at the time of the spring phytoplankton bloom and was lowest during the winter. Differences in the timing of the spring bloom from year to year and between regions of the Gulf indicated that changes in the chlorophyll a:pheopigment ratio were determined primarily by the rate of growth of phytoplankton and were due mainly to variation in the amount of chlorophyll a. No relationship was found between the amount of pheopigment and zooplankton biomass.
Phosphoglucomutase Polymorphism in Brown Shrimp, Penaeus aztecus
Authors: Proctor R. R. , Marvin K. T. , Lansford L. M. , Benton R. C.
Published: April 2011

Eight phenotypes of phosphoglucomutase (PGM) were detected in abdominal muscle extracts from brown shrimp (Penaeus aztecus) by starch-gel electrophoresis. The observed phenotypes were assumed to be under the control of five allelic genes. This assumption was supported by the observed distribution of phenotypes.There were no significant differences in PGM phenotype distribution between sexes or among samples of shrimp taken from Galveston Bay, Texas, and Vermilion and Barataria bays, Louisiana.
An Isolated Population of Arctic Char (Salvelinus alpinus) Inhabiting a Warm Mineral Spring Above a Waterfall at Cache Creek, Northwest Territories
Authors: McCart P. , Bain H.
Published: April 2011

Cache Creek Spring provides an unusual overwintering habitat for a population of Arctic char (Salvelinus alpinus) isolated above a falls impassable to fish moving upstream. During winter, water temperatures (14–16 C) and dissolved solid concentrations (approximately 2600 ppm) are high and oxygen concentrations (0.2–6.8 ppm) are low. Arctic char in the springs differ meristically from those downstream of the falls. The former have significantly more gillrakers (mean 21.7 compared with 21.1) and parr marks (15.1 and 13.5) but fewer pyloric caeca (26.0 and 28.2) and vertebrae (64.7 and 67.1) than the latter. Growth appears similar to that of char inhabiting more typical spring habitats.
Development of Steelhead Trout (Salmo gairdneri) Otoliths and Their Use for Age Analysis and for Separating Summer from Winter Races and Wild from Hatchery Stocks
Authors: McKern J. L. , Horton H. F. , Koski K V.
Published: April 2011

In steelhead trout (Salmo gairdneri) the first pair of otoliths (sagittae) appeared in X-ray photographs of embryos 14 days before hatching and were the first calcified structures visible. Subsequent growth characteristics of otoliths were used in identifying as freshwater and ocean annuli and spawning checks, and indicated seven age-classes and 26 life history patterns among 434 specimens. Diameters of otolith nuclei were smaller (P ≤ 0.01) in summer steelhead (mean = 0.348 mm) than in winter steelhead (mean = 0.436 mm), and diagonally measured otolith growth representing the first year of life was larger (P ≤ 0.01) in hatchery-reared (1.291 mm) than in wild steelhead (0.868 mm for 2/fish and 0.769 mm for 3/fish). Absence of changes in density in the freshwater growth of otoliths from hatchery-reared steelhead and presence of such changes in the otoliths from wild steelhead served as a subjective means of accurately separating the two stocks.
Comment on the Use of Ivlev's Electivity Index with Planktivorous Fish
Authors: O'Brien W. John , Vinyard Gary L.
Published: April 2011

Application to natural fish populations of Ivlev's equation of electivity, by which the degree of choice a predator exhibits in its feeding behavior is determined by comparing the proportion of a particular prey species present in the environment with the proportion present in the gut, has frequently depended upon the incorrect assumption that both predaceous fish and their zooplankton prey are evenly or randomly distributed throughout a water body. In fact, zooplankton tend to clump both vertically and horizontally, and the use of a vertically towed net to determine zooplankton density does not accurately indicate the zooplankton species composition available to a fish feeding at a particular location. Certain zooplankton sampling equipment also may show selectivity or may not capture particular species, so that a difference between the percent species composition of the plankton sample and that of the fish gut may be due to sampling bias rather than fish electivity. Consideration of these problems will enable field researchers to gather more accurate data concerning fish feeding electivity.
The Fish Size, Prey Size, Handling Time Relation in Several Sunfishes and Some Implications
Authors: Werner Earl E.
Published: April 2011

The relation between fish size, prey size, and handling time was determined for bluegill (Lepomis macrochirus) and green (L. cyanellus) sunfishes with both artificial and natural prey. When scaled by plotting handling time against the ratio of prey size to mouth size, the relation was quite general across fish size and species and is described by a modified exponential equation. Handling time increases [Formula: see text] fold as fish approach satiation. Curves of handling time/unit return define optimal prey size for fish of different size and/or species and illustrate comparative aspects of the breadth of diet for different sized sunfish. Certain life history features of the bluegill are interpreted on the basis of these curves. Optimal prey size occurs at a prey size to mouth size ratio of 0.59 regardless of fish size.
Myxosoma cerebralis: Comparative Sensitivity of Spore Detection Methods
Authors: Markiw Maria E. , Wolf Ken
Published: April 2011

Physical and biophysical methods of detecting spores of Myxosoma cerebralis were used in sequence on 87 individual fingerling rainbow trout (Salmo gairdneri) from two populations with a low incidence of infection. Physical methods of releasing spores from the organs of equilibrium, gill arches, or the axial skeleton gave an estimated rate of infection of 2.3–4.6%. Each succeeding step — pepsin digestion, trypsin digestion, and differential centrifugation through 55% dextrose solution — revealed additional infected fish. The final step of the sequence detected 10.5 times more infected fish than were found by examination of the organs of equilibrium or the axial skeleton with physical means; the true incidence was at least 24.1%. Procedures are described for using biophysical methods on 60-fish pools for hatchery inspection work and also on the more bony skeletons of mature fish.
Role of Olfaction and Vision in the Behavior of American Shad (Alosa sapidissima) Homing to the Connecticut River from Long Island Sound
Authors: Dodson Julian J. , Leggett William C.
Published: April 2011

Twenty-two adult American shad (Alosa sapidissima), captured, sensory-impaired, sonic-tagged, and released adjacent to and 10 km west of the Connecticut River, were tracked in Long Island Sound in 1972. Both anosmic and blind/anosmic shad oriented into the tidal current and altered swimming speeds in relation to changes in tidal current velocity as do unimpaired fish. They did not, however, exhibit the consistency in these behavioral responses that resulted in westerly displacement in unimpaired shad. Blind shad exhibited neither of these behavior patterns but did tend to affect a westerly displacement in Long Island Sound.Dart-tagged adult shad that were sensory-impaired and released without displacement in the same areas of Long Island Sound in 1971 and 1972 homed less successfully to the Connecticut River than did unimpaired dart-tagged shad released in the same years. Anosmic dart-tagged shad located the Connecticut River less successfully than unimpaired shad. Blind shad successfully located the river from 10 km distance but failed to do so when released adjacent to the river. Blind/anosmic shad failed to locate the river from either release site.It was concluded that an olfactory–rheotaxic mechanism forms the basis of the location of the Connecticut River by shad. The preferred direction of displacement appears to be established by olfactory clues indicative of the Connecticut River whereas the orientation along the migratory path is maintained by reference to the rate and direction of tidal currents. Vision alone cannot account for this rheotaxic response.
Effect of Temperature and Antigen Dose on the Antibody Response of Juvenile Coho Salmon (Oncorhynchus kisutch) to Aeromonas salmonicida Endotoxin
Authors: Paterson W. D. , Fryer J. L.
Published: April 2011

Specific antibody production in response to an intraperitoneal injection of A. salmonicida endotoxin first occurred in juvenile coho salmon (Oncorhynchus kisutch) held at 6.7, 12.2, and 17.8 C at 4, 2 and 1 wk, respectively. Aeromonas salmonicida endotoxin was antigenic to juvenile coho salmon at all doses between 1 and 5000 μg administered intraperitoneally with and without an aluminum hydroxide carrier.The endotoxin was nontoxic to juvenile coho salmon when 1–5000 μg was injected intraperitoneally and the fish held at temperatures from 6.7 to 17.8 C or when "free endotoxin" was administered by the intramuscular or intraperitoneal route. Aeromonas salmonicida endotoxin was toxic to mice, however.
Immune Response of Juvenile Coho Salmon (Oncorhynchus kisutch) to Aeromonas salmonicida Cells Administered Intraperitoneally in Freund's Complete Adjuvant
Authors: Paterson W. D. , Fryer J. L.
Published: April 2011

The antibody response of a population of juvenile coho salmon (Oncorhynchus kisutch) held at 12 C approached 100% following a single parenteral vaccination with Aeromonas salmonicida cells emulsified in Freund's complete adjuvant. This response indicates that coho salmon behave as a homogeneous population with respect to immunological competence.Fish as small as 1.2 g produced antibodies as early as 4 wk after administration of this vaccine; high levels of antibody persisted for at least 1 yr after injection. This single vaccination provided juvenile coho salmon with protective immunity against furunculosis.
Primary Productivity of the Benthic Microalgae in the Chukchi Sea near Barrow, Alaska
Authors: Matheke G. E. M. , Horner Rita
Published: April 2011

The primary productivity of the benthic microflora was measured using in situ techniques. Primary productivity ranged from below 0.5 mg C m−2 h−1 in winter when the sampling area was covered with ice to nearly 57.0 mg C m−2 h−1 in August. This is 8 times the productivity of the ice algae and twice that of the phytoplankton.
Occurrence of Hematozoa in Atlantic Salmon (Salmo salar) Smolts and Adults in an English River
Authors: McCarthy D. H.
Published: April 2011

The percentages of hemoflagellates found in single samples of Atlantic salmon (Salmo salar) from the River Exe, Devon, in 1971 (122 fish) and 1973 (50 fish) were 33 and 32; of hemogregarines, 18 and 22. The percentages for 21 adults taken in the estuary in August 1971 were 14 and 0, respectively; in 9 adults taken in the estuary in March 1972 and in 9 taken in fresh water in November 1971, no hematozoa were found. Statistical analysis of hemoglobin data showed no significant difference between parasitized and healthy fish. Neither the specific identities nor the vectors of the hematozoa were determined.
Some Details of Fatty Acids and Alcohols in the Lipids of North Atlantic Copepods
Authors: Ackman K. G. , Linke B. A. , Hingley J.
Published: April 2011

Fatty alcohols and fatty acids from both triglycerides and wax esters of a mixed plankton sample consisting mostly of the copepods Centropages typicus, with some Calanus finmarchicus, and a few other organisms, were compared. The alcohols were probably derived from both calanoids and emphasized alc 20:1 (19.2%) and alc 22:1 (44.9%) despite the virtual absence of the corresponding monoethylenic fatty acids. The isomer composition for monoethylenic alcohols parallels that observed for acids in clupeid depot fats and it is suggested that this particular wax ester composition is a result of low density lipids, especially alc 22:1, being deposited during heavy feeding to offset the mass from codeposition of protein and carbohydrate.
Optimization of the salmonid nursery stream
Authors: Mundie J. H.
Published: April 2011

The minimum unit of the environment containing the essential processes of smolt production is identified as a riffle–pool sequence at a meander. Optimization for smolt rearing is seen to lie through control of discharge, temperature, food production, and cover. The pathways of food production are traced. Ways of increasing the stock of fish-food organisms include adjustment of the ratio of riffle to pool area, choice of streamside vegetation, control of light to the stream, and inorganic and organic enrichment. Ways of making food available to fry include collecting drifting invertebrates at night and releasing them in the day, dislodgement of benthos, attracting aerial insects by lights, and supplementary feeding with artificial foods. None of these procedures, when applied to a natural stream, seems economically feasible. When applied, however, to channels made alongside streams and stocked by the parent stream, they should combine some desirable features of rivers with the productive capacity, but not the costs, of hatcheries.
Comparison of Various Vaccines for Inducing Resistance in the Lobster Homarus americanus to the Bacterial Infection, Gaffkemia
Authors: Stewart James E. , Zwicker B. M.
Published: April 2011

Various degrees of resistance to infection of lobsters Homarus americanus by Aerococcus viridans (var.) homari (formerly Gaffkya homari) were induced by vaccines prepared in different ways. Vaccines consisting of formalin-killed cells of a virulent strain of the pathogen (grown in vitro and in vivo) gave a low level of protection, i.e. the vaccinated lobsters were able to resist challenges of 200 bacteria/kg host body weight. A vaccination approach utilizing a low initial dose of the antibiotic, vancomycin, followed 24 h later by injection of 1 × 106 live pathogen cells/kg body weight produced a high degree of resistance to subsequent challenge at times considerably beyond the clearance times for the antibiotic. Fatal infections in normal lobsters are readily established with 10 pathogen cells/kg body weight whereas treatment of lobsters with the vancomycin-live pathogen combination resulted in an LD50 of 2 × 107 live pathogen/kg body weight. It is suggested that the relative effectiveness of the various vaccines is related directly to the concentrations of cellular components within the pathogen, possibly precursors of cell wall mucopeptides.
Early Development and Distribution of the Flathead Sole (Hippoglossoides elassodon)
Authors: Alderdice D. F. , Forrester C. R.
Published: April 2011

Laboratory studies were conducted on eggs from a southern British Columbia population of Hippoglossoides elassodon. Salinity of neutral buoyancy of eggs decreased from about 25% shortly after fertilization to 17–18% at hatching. The incubation period ranged from 20.9 days (2.36–4.0 C) to 7.2 days (10.65 C). At temperatures of 5.5 C or lower and salinities of 19‰ or lower, larvae tended to hatch at a less advanced stage of development. Mean length of newly hatching larvae increased in successive periods throughout the hatching interval. At mean hatching time, larval length varied from 3.2 mm (15‰, 3.0 C) to 6.3 mm (25‰ 6 C). Larvae from eggs incubated over the range of test conditions (10.42–39.58‰, 2.36–10.65 C) reached a length of 6.9–7.2 mm at yolk exhaustion. Hatching success was highest in trials at 25‰, 6 and 7 C; maximum percent viable hatch is predicted at incubation conditions of 29.16‰, 7.38 C. Posthatching larval survival appeared normal at salinities of about 20–37‰ and temperatures of about 5.5 to >10.65 C. Extensive early larval mortality occurred at salinities of 19‰ or less and at temperatures below 5.5 C. Incipient low lethal temperature levels are estimated to be near 3.5–4.0 C for incubating eggs and 4.0–4.5 C for larvae.Egg and larval characteristics of the experimental material were compared with similar data from the literature on North Pacific Ocean Hippoglossoides. A number of previous distinctions made between eggs and larvae of H. elassodon, H. robustus, and H. dubius require further validation owing to the possible confounding of genetic and environmental influences on the attributes studied. Distribution and abundance of H. elassodon over its North American range is discussed on the basis of the evidence gathered.
Three-Dimensional Computer Graphics in Fisheries Science
Authors: Brown Daniel J. , Low Loh Lee
Published: April 2011

These illustrations of three-dimensional computer-generated graphics depict the emergence of definable areas of fisheries science where computer-drawn images yield a visual feeling for the behavior of multidimensional variables. The images are perspective and orthographic projections of a three-dimensional array of connected points which are used to present the results of computer analysis, thus reducing voluminous amounts of complex data into more easily understood visual images. The examples collected here transform information from computer models into conceptual form for humans.
Social Conditions Increase Intermolt Period in Juvenile Lobsters Homarus americanus
Authors: Cobb J. Stanley , Tamm George R.
Published: April 2011

Fifth and eleventh stage lobsters held in pairs showed significantly longer time between molts than did controls reared individually. In pairs the first animal to molt did not delay ecdysis in the fifth stage, but delayed up to 32% of the control molt period in the eleventh stage. In the fifth stage the second lobster to molt delayed up to 32% and in the eleventh stage up to 71%. Similar differences in time between molts were seen in both an open and a recirculating seawater system.
Institutional Constraints in Fisheries Management
Authors: Thompson Peter C.
Published: April 2011

The management of the Canadian fisheries is under the authority of both federal and provincial governments. While it is common to the Canadian confederation that both levels of government have dual roles in many areas of Canadian life, the situation with respect to the fisheries tends to be more complicated in the intricacies of federal–provincial jurisdiction. The result has led at times to a genuine confusion as to the management prerogatives over the Canadian fisheries.In order to manage the resource it is considered requisite to have an understanding of the legislative prerogatives of the federal and provincial agencies responsible for Canadian fisheries. Such an understanding will serve to outline institutional constraints imposed upon fisheries managers.This paper examines a unique aspect of the fisheries resource that being the nature of the governmental responsibilities in the management of the fisheries. This is achieved through the examination of the evolution of the Canadian federation, the constitution, the legal aspects of the fisheries, and the leading judicial decisions on Canadian fisheries.
Identification of Anisakis Larva (I) as Anisakis simplex (Rudolphi, 1809, det. Krabbe 1878) (Nematoda: Ascaridata)
Authors: Pippy John H. C. , Banning Paul van
Published: April 2011

Adult parasitic nematodes, previously reared in vitro from Anisakis larvae (I) from herring, mackerel, and Norway haddock from the North Sea, are compared with recent descriptions of valid species and identified as Anisakis simplex (Rudolphi, 1809, det. Krabbe 1878).
Incorporation of Glycerol-3-Phosphate into the Hepatic Lipids of Rainbow Trout, Salmo gairdneri
Authors: Holub B. J. , Connor J. T. H. , Slinger S. J.
Published: April 2011

The incorporation of sn-[14C]glycerol-3-phosphate into the liver lipids of rainbow trout (Salmo gairdneri) was studied using a homogenate preparation. The reaction was dependent upon added palmitoyl-CoA as a source of activated fatty acid and lysophosphatidic acid as well as phosphatidic acid were found by means of thin-layer chromatography to be important metabolic products. The optimal conditions for studying glycerol-3-phosphate acyltransferase activity in the liver of rainbow trout are given. The maximum rate of entry of glycerol-3-phosphate into lipid esters was 91 μ moles/g liver per hour.
Parasites of freshwater fishes — a review of their control and treatment.
Authors: Margolis L.
Published: April 2011

not available
Two New Species of Heterotanytarsus Spärck, with Keys to Nearctic and Palaearctic Males and Pupae of the Genus (Diptera: Chironomidae)
Authors: Sæther Ole A.
Published: April 2011

Two Nearctic species of Heterotanytarsus are described: Heterotanytarsus perennis n.sp. from male imagines, pupae, and fourth-instar larvae; H. nudalus n.sp. from imagines and pupae. These are the first published records and descriptions of Nearctic species of this genus.Keys are given for male imagines and pupae of the four Nearctic and Palaearctic species of the genus.Heterotanytarsus perennis has been recorded only from Marion Lake, British Columbia. The species is univoltine. Heterotanytarsus nudalus has been recorded only from Lake 192, Freshwater Institute Experimental Lake Area, Kenora, Ont. This species is bivoltine. A larva of Heterotanytarsus has been found in Sawley Lake, Algonquin Park, Ont. The findings, together with the absence of the characteristic larva from numerous other localities, indicate both species as northern oligotrophic members of chironomid communities.
Cytotaxonomy of the Salmonid Fish Stenodus leucichthys
Authors: Booke Henry E.
Published: April 2011

The karyotype for the coregonine fish Stenodus leucichthys (determined from squashed blastula preparations) has a diploid number of 74, consisting of 20 metacentric, 14 submetacentric, and 40 acrocentric chromosomes and a total arm number of 108. This karyotype is very similar to that of Coregonus clupeaformis. Stenodus was probably derived from Coregonus by means of Robertsonian translocations during the early stage of coregonine evolution.
Differentiation Between Natural Hydrocarbons and Low Level Diesel Oil Contamination in Cooked Lobster Meat
Authors: Paradis M. , Ackman R. G.
Published: April 2011

A combination of total lipid extraction, column chromatography, and temperature-programmed gas chromatography was required to demonstrate disputed low level diesel oil contamination in cooked lobster meat. A specific diesel oil contaminant was indicated but identifiable components were not greatly in excess of the same compounds which were also found to be a normal background in organoleptically acceptable canned lobster meat.
Shallow-water gammaridean Amphipoda of New England.
Authors: Stock J. H.
Published: April 2011

not available