bluuebunny/crossref_metadata_2025 huggingface dataset:
Infectious Hematopoietic Necrosis Virus: Prevalence in Certain Alaskan Sockeye Salmon, Oncorhynchus nerka
Authors: Grischkowsky Roger S. , Amend Donald F.
Published: April 2011

Infectious hematopoietic necrosis (IHN) virus is reported for the first time in Alaskan sockeye salmon (Oncorhynchus nerka). The virus was isolated from moribund juveniles at Kitoi Bay and from adults of 16 spawning stocks throughout the Bristol Bay, Kodiak Island, Cook Inlet, and the Gulf of Alaska areas.
Mean Value and Variability of Fish Catches in Fluctuating Environments
Authors: Gatto M. , Rinaldi S.
Published: April 2011

The mean value of the catch and its variability due to environmental fluctuations are analyzed for a very general stock-recruitment model. Particular attention is devoted to the comparison of two standard fishing strategies (constant effort and constant escapement) in terms of mean catch, variance in catches, and maximum deviation of catch. It is demonstrated analytically that constant escapement policies should always give higher mean catch, but should give higher catch variance and more extreme catches only under certain conditions of environmental variability.
A Bioenergetics-Based Model for Pollutant Accumulation by Fish. Simulation of PCB and Methylmercury Residue Levels in Ottawa River Yellow Perch (Perca flavescens)
Authors: Norstrom R. J. , McKinnon A. E. , deFreitas A. S. W.
Published: April 2011

A pollutant accumulation model is developed which successfully predicts concentrations of PCBs and methylmercury in tissues of yellow perch (Perca flavescens) from the Ottawa River, Canada. The model is based on pollutant biokinetics coupled to fish energetics. The expression for metabolic rate includes a growth dependent term for estimating the contribution to metabolism of seasonal and annual growth in each age-class. Uptake of pollutant from food is based on caloric requirements for respiration and growth coupled to concentration of pollutant in food and its assimilation efficiency from the diet. Uptake of pollutant from water is based on flow of water past the gills for respiration coupled with concentration of pollutant in water and the efficiency of its assimilation by gills. Pollutant clearance is related to body weight raised to the power of −.58, but is independent of metabolic rate. Under steady state conditions of chronic exposure, the predicted ratio of uptake to clearance is roughly constant at all weights, and the slope of a curve of log pollutant concentration in tissues vs. log body weight can be used to establish the exponent of body weight for clearance.
Metazoan Parasites of Arctic Char (Salvelinus alpinus) from the North Slope of Canada and Alaska
Authors: Mudry Dwight R. , McCart Peter J.
Published: April 2011

Fourteen species of metazoan parasites were recovered from a total of 128 Salvelinus alpinus from the north slope of Canada and Alaska collected between March 31, 1971 and November 5, 1972. The parasites consisted of one monogean, four digeneans, four cestodes, two nematodes, one acanthocephalan, and two copepods. Of the parasites recovered, one was described as a new species (Bulbodacnitis alpinus Mudry and McCart, 1974) and three others are new North American host records (Tetraonchus alaskensis, Cystidicola stigmatura, and Cyanthocephalus truncatus). All of the localities sampled during this study are range extensions of the parasites found.
Homing Behavior and Population Stratification in Central Puget Sound English Sole (Parophrys vetulus)
Authors: Day Dwane E.
Published: April 2011

Tag recovery data for a central Puget Sound English sole (Parophrys vetulus) tagging study in which fish captured at some locations were tagged and released at others suggested the homing of some fish back to their locations of capture. The occurrence of significant homing was verified through an analysis of tag recovery rates at locations of initial capture and locations of release during successive time intervals. The analysis also revealed that fish not displaced during tagging remained essentially at their locations of original capture. These observations evidenced ridged geographic stratification of the population represented by the tagged fish.Both tag recovery data and catch-per-unit-effort data suggested the migration of some English sole out of the area and/or depths of fishing during fall–winter months.
Role of Rearing Experience in Gravel Substrate Selection by Juvenile Rainbow Trout, Salmo gairdneri
Authors: MacCrimmon Hugh R. , Hawkins Christopher M.
Published: April 2011

Laboratory studies on hatchery-reared wild juvenile rainbow trout (Salmo gairdneri) in an experimental raceway show no significant selection (P < 0.05) of test gravel substrates under either nonflowing or flowing (0.03 m/s) conditions regardless of rearing experience. There is no statistical evidence that hatchery conditioning of rainbow trout for gravel substrate selection is likely to be a feasible undertaking.
Overhead-Light Intensity and Vertical Positioning of the Walleye, Stizostedion vitreum vitreum
Authors: Scherer E.
Published: April 2011

Laboratory experiments were devised to test field observations and eye-histological indications that light may strongly influence the spatial distribution of the walleye (Stizostedion vitreum vitreum). In 48 tests, fish were exposed to sequences of three different light intensities in discrete logarithmic steps, viz. 200, 20, 2 lx, in that and in reversed order. The result was an inverse relation between light intensity and height of fish position in the test tank, with highly significant differences between positions at different intensities. This response may provide the basis for a useful technique to detect sublethal levels of environmental toxicants.
Ecological Analysis and the Fry Paradigm
Authors: Kerr S. R.
Published: April 2011

Appreciation of the essential distinction between internal and external methods of analysis is a fundamental component of the Fry paradigm. Investigation of the emergent behaviors of systems, observed at several hierarchical levels of ecological organization, is emphasized in his work. Internal analysis is always preceded by observation of the relevant external variables. The value of this approach is clear when assessed in terms of recent developments in systems theory.
Hepatic Biotransformation of Environmental Xenobiotics in Six Strains of Rainbow Trout (Salmo gairdneri)
Authors: Pedersen Mark G. , Hershberger William K. , Zachariah Prince K. , Juchau Mont R.
Published: April 2011

Six strains of rainbow trout (Salmo gairdneri), each geographically and genetically distinct, were compared in relation to their capacity for hepatic hydroxylation of aniline and benzo[a]pyrene, and reduction of p-nitrobenzoic acid to p-aminobenzoic acid, in vitro. The effects of 3-methylcholanthrene on stimulation of nitro reductase and aryl hydrocarbon hydroxylase were examined. For the three systems studied, a significant pattern was observed with respect to each strain’s capacity for metabolism. Induction experiments suggested that environment may influence gene expression. Enzyme kinetics and spectral properties were also examined, and mechanisms causing variability within and among strains were discussed.
Thermal Tolerance of Stored Fundulus heteroclitus Gametes: Fertilizability and Survival of Embryos
Authors: Kuchnow Karl P. , Foster IV Robert S.
Published: April 2011

Fundulus heteroclitus ova were tested for fertility after storage intervals of 6, 12, 24, 48, 72, and 96 h over a temperature range of 0–30 C (2-degree increments). Sperm were tested after storage intervals of 2, 4, 6, 12, 15, and 24 h over the range of 0–20 C. Ova retained fertility best at 10–14 C, with fertilization rates of 93, 80, and 46% after 24, 48, and 72 h, respectively. Sperm retained fertility best at 0–4 C, with fertilization rates of 85, 59, and 25% after 2, 4, and 6 h, respectively. The shorter time that sperm retained fertility, compared to the ova, was attributed to sperm activity, since all gametes tested were obtained by stripping, which initiates motility in F. heteroclitus sperm.Variation in mortality in stored ova could be attributed to temperature differences. No relation between sperm storage temperatures and embryo mortality was found.
Agonistic Behavior of Captive Goldeye (Hiodon alosoides)
Authors: Fernet D. A. , Smith R. J. F.
Published: April 2011

Captive goldeye (Hiodon alosoides) (ages 0, I, V–VIII) in clearwater tanks demonstrated a well-developed agonistic repertoire which included charging, chasing, nipping, and lateral displays. We postulate that this agonistic behavior serves as a spacing mechanism in goldeye ecology, allowing fish to defend an individual distance or territory. Age 0 and age I fish showed higher frequencies of direct attack than adults (> age V) which used displays more frequently. In paired encounters, females, smaller fish, and introduced fish won more fights than males, larger fish, or resident fish, a situation which differs from the usually accepted relationships between fighting success and size, sex, or residency. Ripe adults were less aggressive than nonripe adults.
Occurrence of R Factors Associated with Aeromonas hydrophila Isolates from Aquarium Fish and Waters
Authors: Shotts Jr. E. B. , Vanderwork V. L. , Campbell L. M.
Published: April 2011

Isolates obtained from aquarium fish and aquarium waters identified as belonging to the Aeromonas hydrophila complex were examined for the presence of R factors imparting conjugal transmissibility of antibiotic resistance to tetracycline and/or sulfa drugs. It was found that 25.5% of the isolates from fish which were resistant to one or more of the screening antibiotics and similarily 14.1% of the isolates from aquarium water carried such R factors. These studies suggest that the prophylactic use of tetracycline may be a predisposing factor in the emergence of R factor-carrying strains of bacteria in aquarium water.
The Number of Genes for Lactate Dehydrogenase in Salmonid Fishes
Authors: Bailey G. S. , Tsuyuki H. , Wilson A. C.
Published: April 2011

Rainbow trout (Salmo gairdneri) that show polymorphism at the ldhHα locus for liver lactate dehydrogenase (LDH) (L-lactate: NAD oxidoreductase, EC 1.1.1.27) have been examined electrophoretically and immunologically. These results show that the ldhHα locus is active in two possible allelic forms, ldhHαA and ldhHαB, in many tissues such as heart, liver, kidney, eye, red blood cell, brain, and pyloric caeca. Quantitative microcomplement fixation tests support the contention that HαA and HαB subunits are allelic variants. These results, combined with electrophoretic studies on brook trout (Salvelinus fontinalis) polymorphic at the ldhHβ locus, lead us to conclude that all isozymes for LDH in salmonid fishes can be accounted for by the activity of four, and possibly five structural loci: ldhHα, ldhHβ, ldhC, ldhMα, and possibly ldhMβ. These results are in contrast to previous suggestions that the multiple lactate dehydrogenases of trout are encoded by 8 or 10 structural genes per haploid genome.
Homing of Artificially Imprinted Steelhead (Rainbow) Trout, Salmo gairdneri
Authors: Cooper Jon C. , Scholz Allan T.
Published: April 2011

Greater numbers of rainbow trout (Salmo gairdneri) exposed to morpholine as fingerlings as compared to trout left unexposed to morpholine as fingerlings homed to a stream scented with this odor (174 vs. 16). In order to locate this stream, the imprinted fish are able to search a distance of at least 13 km. These data support the olfactory hypothesis of homing.
Distribution and Timing of Tag Recoveries from Native and Nonnative Atlantic Salmon (Salmo salar) Released into Big Salmon River, New Brunswick
Authors: Jessop B. M.
Published: April 2011

Recaptures of tagged Atlantic salmon (Salmo salar) released as smolts into the Big Salmon River varied between annual releases with no differences found on the basis of native or nonnative origin. Few were recaptured outside the Bay of Fundy. Distant fisheries in Greenland and Newfoundland take few salmon from Big Salmon River and commercial exploitation within the Bay of Fundy is minor, particularly by the former large fishery off the mouth of the Saint John River.
System for Sampling Large Trawl Catches of Research Vessels
Authors: Hughes S. E.
Published: April 2011

Procedures and sampling gear designed 1) to sample large research trawl catches prior to sorting by species and 2) to reduce catch handling time and permit an increase in the number of hauls per cruise, are discussed and illustrated. The rationale behind the method relies on the hypothesis that species and size stratification in the codend of the trawl are bilaterally symmetrical The codend is positioned above a deck bin prior to releasing the catch so that a sampling net can be lifted from the deck bin to remove about one half of the total catch. The sampled portion is processed on a fish sorting table, and the unused portion brailed overboard by a net which lines the entire deck bin. Tests conducted in Puget Sound indicated that the species composition and length distribution in the sample adequately represented the total catch; errors greater than 25% were usually restricted to species composing less than 5% of the catch, and for dominant species errors were less than 10%.
Protection of Steelhead Trout (Salmo gairdneri) Against Vibriosis with a Living Low-Virulence Strain of Vibrio anguillarum
Authors: Braaten Bruce A. , Hodgins Harold O.
Published: April 2011

Exposure to a living low-virulence strain of Vibrio anguillarum was found to protect steelhead trout (Salmo gairdneri) against a subsequent challenge of highly virulent V. anguillarum. The fish were effectively protected by means of a single intraperitoneal injection or by multiple oral vaccinations.
Role of Aquaculture in Economic Development Within Southeast Asia
Authors: Sribhibhadh Arporna
Published: April 2011

The potential for aquacultural development in Southeast Asia, especially in its extensive coastal areas, is one of great significance in the world’s food production. The region not only has long established traditions in fish culture but also has culturable indigenous species suitable for commercial production as well as general climatic conditions and other natural amenities favorable and conducive to aquacultural practices.In most Southeast Asian countries, although overall economical and agricultural development are critically interdependent, fisheries, in general, are not a major sector of their national economies. Nonetheless, aquaculture is economically, culturally, and nutritionally important to these countries. Social and economic impacts of increased fish supplies in nutrition of the population, more employment opportunities, greater foreign exchange earnings through export, and other multiplier effects resulting from aquacultural development do play important catalytic, as well as direct, contributing roles in the national economic development.
Status and Potential of Pond Culture of Penaeid Prawns in Southeast Asia
Authors: Kuronuma Katsuzo
Published: April 2011

Pond culture of penaeid prawns in the region has been conducted in general as an incidental growing of the prawns into the milkfish ponds which in most cases penetrated from the sea. The growing of prawns in ponds under such "natural process" has not in the past been valued to the same extent as the traditional milkfish cultivation in the region.Recent increased demand for prawns has increased the significance of their pond culture in the region. In the Philippines the mass production of the fry of the largest and sturdiest species, Penaeus monodon, was initiated in large concrete breeding tanks. After stocking in ponds these grew to market size in 4–5 mo. However, further technical improvements are needed.
Culture of Milkfish (Chanos chanos) as a Means of Increasing Animal Protein Supply
Authors: Chen T. P.
Published: April 2011

Among the marine fishes, the milkfish (Chanos chanos) is most successfully cultured in ponds. The total area of milkfish ponds in the three main milkfish producing countries (Indonesia, Philippines, and Taiwan) is about 320,000 ha. Yield of about 2000 kg/ha per yr is being achieved in Taiwan, the yield in Indonesia (340 kg/ha per yr) and Philippines (560 kg/ha per yr) being considerably lower.If the pond management method of Taiwan is adopted, the present 320,000 ha of milkfish ponds of the above mentioned three countries could produce at least 640,000 metric tons of milkfish per year. Production could be further increased by increasing the fish pond acreage. (Philippines has some 400,000 ha of undeveloped mangrove covered swampland that could be developed into fish ponds).Increase of milkfish production by expansion of the cultural areas faces the following problems: 1) limitation of the natural supply of seed fish; 2) market demand; and 3) effects of milkfish farming on local ecology.Little research on milkfish has been done. It is proposed that future research should emphasize: 1) research on artificial propagation of milkfish to supply seed for milkfish farming; 2) research on the nutritional requirements and feeding habits of milkfish; 3) research on modification of present cultural practice to permit polyculture in milkfish ponds; and 4) research on processing milkfish into products of universal acceptance.
Application of Hormones in Fish Culture
Authors: Yamazaki Fumio
Published: April 2011

Methyltestosterone, when incorporated in the diet at a concentration of 1 ppm, accelerated the growth of goldfish (Carassius auratus), horai masu, a variant of rainbow trout (Salmo gairdneri), and kokanee (Oncorhynchus nerka). Simultaneous acceleration in the growth of the testes was also observed in some of the horai masu. Administration of 5 ppm methyltestosterone or diethylstilbestrol in the diet combined with injection of salmon gonadotropin was effective in accelerating the sexual maturation of rainbow trout. However, a concentration of 50 ppm methyltestosterone inhibited gonadal development if the treatment was initiated shortly after hatching and continued for a period of 5 mo. The fish thus treated were found to have threadlike gonads even after 3 yr. Courtship behavior and feeding behavior were also influenced by methyltestosterone treatment. The sex ratio of zebra fish (Zebrafario) and rainbow trout was altered when the administration of methyltestosterone was initiated just after hatching. This suggests a strong possibility of introducing sex reversal or mono sex culture in these important commercially raised fish. Results with the cobalt variant of rainbow trout, a fish lacking a complete pituitary and found only with immature gonads, suggest that this animal may be a promising model for future studies in fish endocrinology.
In Vitro Oocyte Maturation and Ovulation in Rainbow Trout (Salmo gairdneri), Northern Pike (Esox lucius), and Goldfish (Carassius auratus)
Authors: Jalabert Bernard
Published: April 2011

The endocrine processes which control oocyte maturation (resumption of meiosis) and ovulation have been studied in vitro in the trout Salmo gairdneri. Follicular maturation is ultimately under the control of a pituitary gonadotropin which induces the follicle to synthesize specific steroids; these steroids act in turn directly on the oocyte to promote maturation. The systematic study of the in vitro efficiency of various steroids have shown that 17α-hydroxy-20β-dihydroprogesterone plays a preferential role in initiating maturation; this steroid has a high affinity for a plasma protein system. The efficiency of this steroid, similarly to the efficiency of the gonadotropin, can be modulated by other circulating steroids. The precise chronology of some events of follicle maturation have been defined using inhibitors of protein and RNA synthesis.The ovulatory process (sensu stricto: expulsion of matured oocyte from the follicular envelopes) has been experimentally dissociated from oocyte maturation, and some mediators likely to act on ovulation have been identified.These data permit the consideration of novel means of intervention at the ovarian level to synchronize maturation and ovulation in fish, in order to give new tools for progress in aquaculture.
Endocrine Control of Ovulation in Medaka (Oryzias latipes) and Ayu (Plecoglossus altivelis)
Authors: Hirose Keiji
Published: April 2011

This study was undertaken to elucidate the endocrine control of ovulation in the medaka (Oryzias latipes) and the ayu (Plecoglossus altivelis). Among gonadotropins, salmon gonadotropin gave the best response in inducing in vitro ovulation of Oryzias oocytes and demonstrated a higher potency than mammalian gonadotropin, suggesting a degree of zoological specificity. Of the steroids, cortisol was very effective in inducing in vitro ovulation of Oryzias oocytes. Furthermore, ovulation cannot be induced in Oryzias oocytes dissected from their follicular tissues prior to exposure to gonadotropin, suggesting that the hormone acts first on the follicular envelope to produce effective agents (corticoids?) which are then responsible for ovulation. Application of a specific inhibitor (SU-4885) of 11β-hydroxylase resulted in inhibition of gonadotropin-induced ovulation, but did not affect ovulation induced by cortisol. The results suggest that corticosteroidogenesis in the follicular tissues is required for gonadotropin-induced ovulation. However, cortisol failed to induce in vitro ovulation of Oryzias oocytes removed from their follicular tissues. Thus, ovulation may be induced by secondary agents that are produced during corticoid biosynthesis or metabolism within the follicular envelope. Hirose et al. showed in 1974 that gonadotropin-treated mature ayu imbibed a greater quantity of water than control ayu, and that body weight increased by 3% in the hormone-treated fish. These results indicate that water ingestion and hydration of oocytes induced by gonadotropin may be an important process at ovulation. It has also been shown that during maturation and ovulation hydration is associated with ion movement (Na+). These phenomena may be related to the action of gonadotropin and/or corticoids and also occur at ovulation in the medaka. Such information may possibly yield additional clues regarding the mechanism of ovulation in fish and provide a solution to the practical problems of regulating ovulation.
Use of Synthetic Diets and Biochemical Criteria in the Assessment of Nutrient Requirements of Fish
Authors: Cowey C. B.
Published: April 2011

Dietary allowances of nutrients have been formulated mainly from growth–response curves. The use of other criteria, especially those which exploit the biochemical role of nutrients, is discussed by reference to three different nutrients, namely thiamin, magnesium, and essential fatty acids.It is shown that erythrocyte transketolase activity provides a nutritional index of thiamin status in turbot (Scophthalmus maximus). The enzyme is saturated with coenzyme (thiamin pyrophosphate) at a dietary thiamin level of 2.6 mg/kg.Assessment of mineral requirements is shown to present special problems because complex interrelationships exist between some dietary minerals. It is shown that dietary magnesium deficiency (4 mg magnesium/100 g diet) leads to renal calcification in rainbow trout (Salmo gairdneri) at dietary calcium levels of 2.7 g/100 g (Ca: P ratio 1: 1). Elevation of dietary magnesium to 100 mg/100 g under these conditions gave freedom from pathology and enhanced growth.Ratios of certain fatty acids in the tissue phospholipids of rainbow trout are known to provide a useful index of essential fatty acid status. These ratios cannot be applied to turbot as this species does not chain elongate and desaturate 18-carbon acids at appreciable rates. Long chain polyunsaturated fatty acids of the ω3 series must be supplied preformed in the diet of turbot.
Factors Affecting Maximization of Fish Growth
Authors: Weatherley A. H.
Published: April 2011

Studies of fish growth bioenergetics include investigations of variables such as Standard Metabolic Rate (SMR), Specific Dynamic Action (SDA), and activity. There is now an increasingly sophisticated attempt to measure these and other components of bioenergetics, such as foraging and other forms of activity, and relate growth to them in mathematical expressions. Such expressions can be very valuable in identifying the parameters that remain to be determined in the field or experimentally for a full and formal accounting of growth energetics. Energy compartmentalization studies can form the factual basis in a superior management of cultured fish populations for growth (and production) maximization and can offer a necessary framework for the genetical improvement of growth which has been lacking hitherto.Knowledge of fat and protein dynamics can permit optimization of production of useful materials by fish if that is considered an advantage over the usual attempts to maximize growth and production of fish as caloric units.Cell biology, determination of optimal vitamin levels, and the mechanisms of hormonal control of growth may offer additional research problems leading to growth maximization.The structure of fish growth curves should be studied because they can reveal differences about the assimilative capabilities of fish not only between species, but also between life stages or in different environments.The study of growth is a multidisciplinary program, demanding inputs of information from a number of fields, which bears the promise of a perhaps dramatic improvement in production of fish from aquaculture.
Genetic Techniques in Flatfish Culture
Authors: Purdom C. E.
Published: April 2011

Selection for improved growth rate does not appear to be feasible in flatfish because the environmental component of variation is very large. Selection for other characters has not been studied. The development of inbred lines, and their use in F1 hybrid production, seems warranted in fish farming if only as a means of avoiding inbreeding depression of fitness. Gynogenesis may be a practical means for accelerating the rate of inbreeding in fish. Induced triploidy is a potentially useful technique in fish culture in that it prevents sexual maturation and limits the depression of growth associated with this. Hybridization is a common phenomenon among fish and can lead to a form of hybrid vigor. Its application in fish culture may be limited by marketing problems where fish are sold under a specific name.
Applications of Biochemical Genetics to Aquaculture
Authors: Hedgecock Dennis , Shleser Robert A. , Nelson Keith
Published: April 2011

American lobster (Homarus americanus) catches are diminishing. More than 90% of the annual catch is 2.2-kg (1-lb) minimum legal size. Females of this size may have produced 10,000 eggs prior to catch, but, with an estimated larval survival of 1/100,000, 10 females are required to reproduce 1 female. The prognosis for the lobster fishery appears poor.Laboratory culture of larval lobsters can achieve more than 60% survival at a cost of about 2¢ per postlarval juvenile. The effectiveness of restocking has never been evaluated.Starch-gel electrophoresis reveals protein differences among individual lobsters: progeny studies confirm Mendelian inheritance of allozymes encoded by five independent genes, Est-2, Idh, Pgi-3, Pgi-4, and Pgm-1. Genetic markers may be determined by biochemical analysis of pereiopod tissue, without killing. Allozyme frequencies have been measured in natural populations (e.g. Pgm-1103 is absent in lobsters from Martha’s Vineyard (MVS), but occurs elsewhere in frequencies of 0.C2). Larvae with rare allozyme genotypes (e.g. Pgm-1100/103 or Pgm-1103/103 at MVS) may be obtained from selected females or produced by appropriate matings. These may be released, and their survival at selected times after release monitored by leg sampling from lobsters of the appropriate age-class. This technique is being used to select diverse parental stocks and produce progeny which may show hybrid vigor. These stocks will be used in developing lobster farming.
Thermal Requirements of the Early Life History Stages of Walleye, Stizostedion vitreum vitreum, and Sauger, Stizostedion canadense
Authors: Koenst Walter M. , Smith Jr. Lloyd L.
Published: April 2011

Walleye (Stizostedion vitreum vitreum) and sauger (Stizostedion canadense) eggs were exposed to temperatures ranging from 6 to 21 C to determine temperature effects on fertilization, incubation, and fry survival. Optimum fertilization temperatures were 6–12 C for walleye and 9 C for sauger. Optimum incubation temperatures were 9–15 C for both walleye and sauger. A sharp drop or rise in temperature had no great effect on walleye fry and juvenile survival. Optimum temperature for juvenile walleye and sauger growth was 22 C. When acclimated at 8–26 C, 96-h upper lethal temperatures for walleye juveniles were 27.0–31.6 C, with the lower acclimation temperatures producing the lower upper lethal limits and intermediate acclimation producing intermediate upper lethal limits in order as acclimation temperatures increased. When acclimated at 10–26 C, the 96-h upper lethal temperatures for sauger juveniles was 26.6–30.4 C, in order as with the walleye.
Parasites as Potential Biological Tags of Atlantic Salmon (Salmo salar) smolts in the Miramichi River System, New Brunswick
Authors: Hare G.M. , Burt M. D. B.
Published: April 2011

Ten parasite species (one protozoan, eight helminth, one mollusc) were collected from 1262 smolts of Atlantic salmon (Salmo salar) in the eight tributaries and estuary of the Miramichi River, New Brunswick, Canada during 1970 and 1971. Three of these parasites, Discocotyle sagittata, Diplostomum spathaceum, and Neoechinorhynchus rutili showed restricted distributions within the study area. Discocotyle sagittata infected 32.6% of 435 smolts collected from tributaries draining into the Main Northwest Miramichi River but only 0.3% of 604 smolts collected from tributaries draining into the Main Southwest Miramichi River. Diplostomum spathaceum infected 18.9% of 148 smolts collected from the Southwest Miramichi River but was absent in 819 smolts collected from the remaining tributaries. Neoechinorhynchus rutili infected 18.8% of 144 smolts collected from the Bartholomew River but only 0.2% of 895 smolts collected from the other tributaries. Presence of Discocotyle sagittata on smolts collected in the estuary of the Miramichi River would identify smolts that originated in the Main Northwest Miramichi River, thus allowing for a separation of smolts from this branch and the other main branch, the Main Southwest Miramichi River. Presence of Diplostomum spathaceum in smolts collected in the Main Southwest Miramichi River or in the estuary of the Miramichi River would identify smolts that originated in the Southwest Miramichi River. Presence of N. rutili in smolts collected in the Main Southwest Miramichi River would identify smolts of Bartholomew River origin.
Lipid Composition of Slender Tuna (Allothunnus fallai) as Related to Lipid Composition of Their Feed (Nyctiphanes australis)
Authors: Bishop David G. , James David G. , Olley June
Published: April 2011

The depot lipids of specimens of slender tuna (Allothunnus fallai) were characteristic of the zooplankton (Nyctiphanes australis) on which each was feeding. The lipids of the "krill" and of the depot fats were unusually rich in eicosaenoic and docosahexaenoic acids, although the fatty acid composition of samples of "krill" from individual tuna stomachs varied markedly and this variation was reflected in the fatty acid composition of the tuna depot lipids.Because of the nature of their diet, the composition of the depot lipids of the slender tuna varied significantly from those of other tuna species. However, the liver lipids of the slender tuna were more characteristic of all fish liver oils.
Hyponeustonic Fish Larvae in the Northumberland Strait During Summer 1962
Authors: Faber Daniel J.
Published: April 2011

A neuston net with mesh openings of 1.3 mm was towed in the surface waters of the north basin of the Northumberland Strait at irregular intervals from mid-June to mid-September 1962. Fifteen genera of teleost larvae belonging to 11 families were collected. Of these, the following eight species occurred in regular abundance and were termed "abundant larvae": sand lance, Ammodytes americanus; radiated shanny, Ulvaria subbifurcata; lumpfish, Cyclopterus lumpus; fourbeard rockling, Enchelyopus cimbrius; Atlantic mackerel, Scomber scombrus; cunner, Tautogolabrus adspersus; white hake, Urophycis tenuis; and Atlantic herring, Clupea harengus harengus. Larvae were collected in variable numbers, with the sampling data suggesting they were aggregated in the water. The total abundance of all larvae was about 50 larvae per tow except for a peak in July. The regular appearance of the "abundant larvae" resulted in unique combinations of spawning and hatching times for each species. The larvae of spring-spawners were present in June and were gradually replaced by the larvae of summer-spawners.
Migrating Atlantic Salmon (Salmo salar) Caught by Otter Trawl on the Newfoundland Continental Shelf
Authors: Lear W. H.
Published: April 2011

Fifty-four Atlantic salmon (Salmo salar) were reported from incidental catches of otter trawls on the continental shelf off Newfoundland during 1933–74. Fifty percent of the captures were taken along the southwest edge of the Grand Bank. On the basis of weights, 19% of the salmon were presumed to be 1-sea-winter salmon, 60% were 2-sea-winter salmon, 19% were 3-sea-winter salmon while 2% had previously spawned. It is postulated that the southwestern Grand Bank may form a winter–spring migration route for Atlantic salmon enroute to southern and western Newfoundland, the Maritime provinces, and Quebec.
A Rapid Method for Measuring the Acute Toxicity of Pulpmill Effluents and Other Toxicants to Salmonid Fish at Ambient Room Temperature
Authors: McLeay Donald J.
Published: April 2011

A residual oxygen bioassay performed at ambient room temperature is examined as a rapid method for measuring the acute toxicity of pulpmill effluents and other toxicants to salmonid fish. Test results are evaluated in comparison with 96-h LC50 bioassays.At test temperatures of 19–22 C and coho salmon (Oncorhynchus kisutch) loadings of 4–5 g/liter, residual oxygen levels were elevated in effluent concentrations equivalent to 0.5–0.9 of the samples’ 96-h LC50 values; these tests were completed within 5–6.5 h. Sensitivity increased only slightly with a loading of 1 g/liter and this test required 18 h for completion. Decreasing the number of fish per jar from 4 to 1 while holding fish loadings constant by varying the size of the test containers did not alter the test’s sensitivity. Results indicate that, with a loading of 4–5 g fish/liter and 10 replicates of 1 fish/jar, a residual oxygen bioassay at ambient room temperature is more sensitive than a 96-h LC50 batch replacement bioassay (2 liters/g fish per day). Under these conditions fish requirements are identical; the residual oxygen test is completed within 6.5 h and 32- to 40-fold reduction in volume of test solutions required is achieved.The procedure was evaluated with rainbow trout (Salmo gairdneri) using dehydroabietic acid, zinc, phenol, and lindane. Significant responses occurred with these toxicants at concentrations equivalent to 0.5–1.0 of the samples’ 96-h LC50 values and higher.
Phosphate Exchange and Organic Phosphorus Excretion by Freshwater Algae
Authors: Lean D. R. S. , Nalewajko C.
Published: April 2011

Rates of uptake and release of phosphorus compounds by four species of freshwater algae grown in axenic culture at phosphorus concentrations similar to lake water showed that an exchange of phosphate between the cells and the medium was the principal phosphorus flux. Algal-P showed turnover times as short as 69 min but no regular growth phase–turnover time relationship was found. During growth of the cultures, phosphate in the medium became depleted and turnover times as short as 2.7 min were measured. Significant amounts of dissolved organic phosphorus (DOP) were excreted. Some appeared to be of colloidal size.
Molecular Activation Analysis and Its Application to Methylmercury Determination in Various Marine Samples
Authors: Jong I. G. de , Wiles D. R.
Published: April 2011

A novel method is described by which nuclear activation analysis can be used to determine the chemical form in which certain elements occur. The radiochemical retention of molecular identity is constant for a given type of sample and can be easily determined. Application of this method for quantitative estimation of methylmercury in fish protein concentrates and in blood is described in detail and the results discussed. The results are reliable and reproducible. Radiochemical retention depends on the species of fish, perhaps because of gamma radiolysis of the sample. An alternative method is also described which, although less direct, is free from many of the common interferences, such as sodium and phosphorus. This method, also useful for blood analysis is appropriate for use at remote sampling stations.
Effects of Chronic DDT/DDE Exposure on Anesthetic Induction and Recovery Times in Rainbow Trout (Salmo gairdneri)
Authors: Klaverkamp J. F. , Lockhart W. L. , Metner D. , Grift N.
Published: April 2011

In rainbow trout (Salmo gairdneri) fed pellets containing 4.55 μg/g of p,p′-DDT and 6.81 μg/g of p,p′-DDE every other day, anesthetic induction and recovery times of phenoxyethanol (PE) were less than those in trout fed control pellets. No interactions were observed in fish fed DDT/DDE and anesthetized with ethyl m-aminobenzoate methanesulphonate (M.S. 222). Differences observed between fish fed DDT/DDE and anesthetized with PE as compared to M.S. 222 could be due either to enhanced metabolism of PE or to the fact that PE and M.S. 222 have different modes or sites of action.
Effect of Copper on Some Aspects of the Bioenergetics of Rainbow Trout (Salmo gairdneri)
Authors: Lett Patrick F. , Farmer G. J. , Beamish F. W. H.
Published: April 2011

The influence of sublethal concentrations of total copper on the appetite, growth, and proximate body composition of rainbow trout (Salmo gairdneri) held in hard water (365 mg/liter) was measured over a 40-day interval. The initial response of trout exposed to concentrations of copper ranging from 0.0 to 0.3 mg/liter (the 96-h LC50 was 0.25–0.68) was the cessation of feeding. Thereafter, food intake gradually returned to amounts observed for control fish, the rate of return of appetite being dependent on copper concentration and ration level. Growth rate of trout exposed to copper (0.075–0.225 mg/liter) and fed rations of either 0.25 or 1.5% dry food wt/wet fish wt per day was initially depressed but approached values observed for control fish near the end of the 40-day interval. During this period, lipid, protein, and moisture offish exposed to copper did not change significantly. Initial growth retardation was not attributable to the inability of copper-exposed fish to digest their daily rations. Results are discussed in terms of the ability offish to adapt to stress imposed by sublethal concentrations of heavy metals.
Effects of Dietary Aroclor® 1242 on Channel Catfish (Ictalurus punctatus) and the Selective Accumulation of PCB Components
Authors: Hansen L. G. , Wiekhorst W. B. , Simon J.
Published: April 2011

Channel catfish (Ictalurus punctatus) fingerlings fed a diet containing 20 ppm Aroclor® 1242 for 20 wk responded with a reduced weight gain and liver hypertrophy when compared to controls. When treated fish were fed the control diet for 8 subsequent wk followed by 8 additional wk of Aroclor® feed, they approached control values for liver weight and surpassed the rate of gain for control fish. No histopathological lesions were observed in the fish fed PCB. The total PCB in fish declined slightly during an 8-wk PCB-free period beginning at week 12, but the PCB burden remained constant when the PCB-free period was begun at week 20. During PCB-free periods, there was a shift in residues from the edible carcass to the offal. Residues are discussed as components as well as total PCB. We found that a tetrachlorobiphenyl is more persistent than some higher chlorinated components and that various tissues accumulated different profiles of components.
Nitrogen and Phosphorus Removal from Lakes by Fish Harvest
Authors: Bull C. J. , Mackay W. C.
Published: April 2011

Phosphorus (P) made up 0.3–0.5% of the wet weight of four species of fish. Nitrogen (N) accounted for a further 2.4–2.9%. If the maximum annual yield of fish was harvested from the lakes studied, less than 1% of the phosphorus and nitrogen entering the lake would be removed. On the basis of our data fish harvest would apparently not significantly slow nor reverse the process of eutrophication.
Viral Nature of Piscine Erythrocytic Necrosis (PEN) in the Blood of Atlantic Cod (Gadus morhua)
Authors: Appy R. G. , Burt M. D. B. , Morris T. J.
Published: April 2011

Piscine erythrocytic necrosis (PEN), a degenerative disease of erythrocytes of Atlantic cod (Gadus morhua), is described at the electron microscope level and compared with light microscope findings. PEN infection is found associated with a cytoplasmic pool of hexagonal particles reminiscent of large icosahedral cytoplasmic deoxyriboviruses (ICDV). Fibrillar strands appear associated with the infection. PEN is compared with other possible ICDV infections in various poikilotherm vertebrates and is considered to be included in a distinct ICDV subgroup which also contains virions associated with infections of Pirhemocyton, Toddia, rock blenny infections, and perhaps lymphocystis.
Serological Comparison of Flexibacter columnaris Isolates Using Rabbit and Rainbow Trout (Salmo gairdneri) Antisera
Authors: Sanders J. E. , Holt R. A. , Fryer J. L.
Published: April 2011

Bacterial agglutination tests with antisera from rabbit and rainbow trout (Salmo gairdneri) revealed a common antigen(s) in each of the three isolates. Assays with adsorbed antisera from both species indicated that the three isolates belonged to two serological groups with each group having its own unique antigen(s). These similarities with rainbow trout and rabbit antisera indicate that the serotypes of Flexibacter columnaris as defined by rabbit antisera are like those recognized by salmonids. This suggests that these distantly related vertebrates both responded to the same surface antigens of the F. columnaris isolates.
Temperature Effects on Lactate–Glycogen Metabolism in Zinc-Intoxicated Rainbow Trout (Salmo gairdneri)
Authors: Hodson Peter V.
Published: April 2011

Acute, lethal exposures of fish to zinc cause gill damage and subsequent death through tissue hypoxia. This experiment showed that lactic acid production and glycogen utilization in dorsal white muscle of rainbow trout (Salmo gairdneri) increased with time of exposure to a lethal concentration of zinc. Exposure of trout to zinc at 3, 11, and 19 C did not affect the timing or percentage change of lactic acid production or utilization of glycogen. Therefore, the previously observed high tolerance of zinc by warm-acclimated fish is not due to increased resistance to the tissue hypoxia caused by gill damage.
Individual Marking of Soft-Bodied Intertidal Invertebrates In Situ: a Vital Stain Technique Applied to the Sea Anemone, Anthopleura xanthogrammica
Authors: Sebens Kenneth P.
Published: April 2011

The technique, employing a concentrated solution of neutral red dye, allows application of identifying marks in situ with minimal disturbance of the organism. Tests showed that the marks persisted for at least 12 mo.The success of the method indicates its general utility for marking soft-bodied invertebrates which have previously proved unsusceptible to long-term individual marking.
A Natural Epizootic of Infectious Hematopoietic Necrosis in Fry of Sockeye Salmon (Oncorhynchus nerka) at Chilko Lake, British Columbia
Authors: Williams Ian V. , Amend Donald F.
Published: April 2011

The first confirmed epizootic of infectious hematopoietic necrosis virus disease under natural conditions is reported for sockeye salmon, Oncorhynchus nerka, in Chilko Lake, British Columbia. The outbreak occurred among fish of the 1972 brood during the spring of 1973. An estimated 825.6 million eggs were deposited in the Chilko River in 1972, and the production of 31.4 million fry that migrated into the lake in 1973 was significantly lower than the 55.1 million fry expected. The egg-to-fry survival of 3.8% was the lowest ever recorded at Chilko Lake (1949–73). The estimated fry-to-smolt survival of 57.1%, however, was well within the normal range for this lake. Apparently IHN severely reduced the survival of the 1972 brood of sockeye salmon fry at Chilko Lake, and all or nearly all of the reduction occurred during the egg-to-fry stage of the life cycle.
Influence of Bovine Growth Hormone and L-Thyroxine on Growth, Muscle Composition, and Histological Structure of the Gonads, Thyroid, Pancreas, and Pituitary of Coho Salmon (Oncorhynchus kisutch)
Authors: Higgs David A. , Donaldson Edward M. , Dye Helen M. , McBride J. R.
Published: April 2011

Groups of underyearling coho salmon (Oncorhynchus kisutch) were acclimated to 10 C well water and a photoperiod of 12 h L:12 h D. Excess ration (Oregon Moist Pellet) was presented daily. Doses of bovine growth hormone (5, 10, 20, 30, or 90 μg bGH/g body wt) and L-thyroxine (0.5, 5, or 30 μg T4/g) were administered over a period of 84 days (phase I) either by injection (via dorsal musculature or peritoneal cavity) or by hormone cholesterol implants into the muscle. Administration frequency of bGH and T4 was such (range 2 times/wk-1 time/3 wk) that fish theoretically received either 10 or 30 μg bGH/g per wk or 1 or 10 μg T4/g per wk. Control fish received either alkaline saline (pH 9.5) or a cholesterol pellet. After cessation of treatment the fish were observed for an additional 84 days (phase II). During phase I, growth rates (weight) for bGH fish (2.0–2.4% per day) and for T4 fish (0.97–1.1% per day) were significantly higher than those of control fish (0.42–0.59% per day). Among bGH fish, dorsal musculature injection (2 times/wk) was significantly more effective than intraperitoneal injection (1 time/2 wk).Increases in weight above control for bGH fish at 84 days ranged from 220 to 369%. Those for T4 fish extended from 47 to 78%. In phase II, control fish growth rates were higher (0.61–0.67% per day) than those for bGH fish (0.47–0.57% per day) and T4 fish (0.32–0.44% per day). Administration of bGH and T4 (high dose) caused a progressive decline in condition factor of fish from the control range. This trend was stopped and reversed in phase II.At 84 days, generally no significant differences were detected among groups for percentages of muscle water. However, some groups had significantly higher (bGH) and others lower (T4) percentages of muscle protein relative to those of control fish. Also, significant increases (T4) and decreases (bGH) in muscle lipid percentages were found. Hormone treatment altered the histological structure of the ovary, thyroid, exocrine (T4) and endocrine (bGH) pancreas, and somatotrop cells (T4) of the pituitary. A poor growth response was noted for two groups of coho administered bGH after acclimation to sea water.