bluuebunny/crossref_metadata_2025 huggingface dataset:
Uptake of Mercury by Freshwater Clams (Family Unionidae)
Authors: Smith Annette L. , Green Roger H. , Lutz Andrew
Published: April 2011

Mercury concentrations were measured in water, sediments, and three species of clams from lakes with and without reported mercury contamination. Elevated mercury levels in clams were associated with elevated mercury levels in water and sediments.Uncontaminated clams were exposed to three mercury compounds at 1.0, 10, 50, and 100 μg Hg/liter for up to 3 wk in the laboratory. The clams concentrated the metal in the order methylmercuric chloride > phenylmercuric acetate > mercuric chloride. The rate of uptake of mercury increased with increasing mercury concentration in the water. In most cases, temperature had no effect on the rate of mercury uptake or elimination.The distribution among organs depended on the compound to which the clams had been exposed. Only methylmercuric chloride was concentrated extensively in foot muscle. Transfer of methylmercuric chloride among organs apparently continued after exposure to the compound had ended.
Metabolism of Pyruvate in Postmortem Adductor Muscle of the Sea Scallop (Placopecten magellanicus) During Iced Storage
Authors: Sakaguchi M. , Hiltz Doris Fraser , Dyer W. J.
Published: April 2011

Glycolytic metabolic pathways in postmortem adductor muscle of the sea scallop (Placopecten magellanicus) during iced storage were studied by means of 14C-pyruvate injected into the muscles. Ion-exchange fractionation of perchloric acid extracts of muscle into cationic, anionic, and neutral components showed that the radioactivity derived from 14C-pyruvate was rapidly incorporated into the cationic fraction during the postmortem storage period. Subsequent ion-exchange chromatography revealed that most of the radioactivity in the cationic fraction was distributed among three major peaks, whose components were identified by paper chromatography as (Peak I) alanine, (Peak II) α-amino-n-butyric acid and an unidentified compound, and (Peak III) octopine. These findings indicate that the disposition of pyruvate in postmortem scallop muscle is mainly via two pathways: transamination to amino acids, and reductive condensation with arginine to octopine. This metabolic pattern in muscles injected immediately after shucking (0-day series) did not differ significantly from that in muscles injected after preliminary storage of the shucked meats for 4 days in ice (4-day series).
Migrations and Biological Characteristics of Atlantic Mackerel (Scomber scombrus) Occurring in Newfoundland Waters
Authors: Moores J. A. , Winters G. H. , Parsons L. S.
Published: April 2011

Mackerel migrate to Newfoundland waters from July to November and exhibit periodic fluctuations in abundance. Recent taggings have shown extensive migrations from Newfoundland to ICNAF Statistical Area 6. Various biological characteristics of mackerel from Newfoundland waters are reported and compared with those for mackerel caught in the New England area. A consideration of tagging results, biological characteristics, and ecological factors indicates that for assessment purposes mackerel inhabiting ICNAF Subareas 3–6 should be treated as one stock rather than assessed separately as northern and southern contingents each with a separate quota.
Movement, Growth, and Survival in a Stream Population of Wild Brook Trout (Salvelinus fontinalis) During a Period of Removal of Non-Trout Species
Authors: Flick William A. , Webster Dwight A.
Published: April 2011

No well-defined changes in growth and survival rates of native brook trout (Salvelinus fontinalis) were detected during a 13-yr period when non-trout species were removed from a small Adirondack Mountain stream using fixed traps located throughout the system. The catch of non-trout species was about 124,000 weighing 2000 kg, and of trout, 13,000, weighing 500 kg. Slow growth characterized the population through this time, with mean lengths of 13.2, 17.3, and 21.3 cm at ages I+, II+, and III+, respectively. The weighted annual survival rate for ages II–V was 18%, with most deaths due to natural causes. The most striking observation was virtual cessation of movement of both trout and non-trout species after 7 yr, suggesting that the removal program had an effect on population behavior, even if it was not reflected in an improvement in trout growth.
Sedimentation of Organic Matter in St. Margaret’s Bay, Nova Scotia
Authors: Webster T. J. M. , Paranjape Madhu A. , Mann K. H.
Published: April 2011

Sediment traps were placed at two sites in St. Margaret’s Bay. At a deep station (70 m), traps were placed 5 m and 10 m above the bottom; at a shallow station (10 m), six traps were placed between 45 and 197 cm above the bottom. Total catch averaged 118 g C m−2yr−1 at the deep station and 134 g C m−2yr−1 at the shallow station. The most probable source of the organic matter was detritus derived from seaweeds and seagrasses, but the most probable source of inorganic material was bottom sediment. It is suggested that the traps were taking bottom sediment resuspended from shallow water, enriched by detritus from seaweeds and seagrasses.
Life History Observations on the Puget Sound Rockfish, Sebastes emphaeus (Starks, 1911)
Authors: Moulton Lawrence L.
Published: April 2011

Large concentrations of Puget Sound rockfish (Sebastes emphaeus) were found at three locations in the San Juan Islands, Washington, at depths ranging from 10 to 25 m. Spawning females were found in August and September, the latest maturing Sebastes in this region. The existence of ripe females indicates that the taxon is not the juvenile form of another species. Total lengths of mature females ranged from 130 to 179 mm, and wet weights from 21 to 79 g. Fecundity estimates ranged from 20, 177 for a 150-mm female to 57, 103 for a 179-mm specimen. The age at maturity ranged from age II to age IV. Field and aquarium behavioral observations indicate that the species is adapted to crevice and cave existence in areas of strong currents and rocky substrate.
Preheat Treatment for Improvement of Frozen Storage Stability at −10 C in Fillets and Minced Flesh of Silver Hake (Merluccius bilinearis)
Authors: Lall Barbara Smith , Manzer Alison R. , Hiltz Doris Fraser
Published: April 2011

Dimethylamine (DMA) formation occurs in the muscle of silver hake (Merluccius bilinearis) during frozen storage. The rate of its formation in fillets and minced flesh during subsequent frozen storage for 1 mo at − 10 C is not affected by preheating at temperatures up to 60 C. Preheating to 80 C, however, greatly retards DMA development. Lipid hydrolysis (free fatty acid accumulation) is arrested by preheating to 60 C, but is little affected by preheating at temperatures up to 45 C. These deteriorative reactions are faster in minced flesh than in fillets, and in materials prepared from summer (spawning) fish than in those prepared from winter fish.In breaded fishery products, preheat treatment as presently practiced is insufficient to inactivate these deteriorative enzymic reactions in sensitive gadoid species such as the hakes and pollocks.
Linear Regressions in Fishery Research: Some Comments
Authors: Jolicoeur Pierre
Published: April 2011

When a statistical relationship has to be described between two variates that are both subject to errors or fluctuations, the standard major axis, advocated recently in this journal under the name GM regression, is unsuitable. The ordinary major axis or, even better, the bivariate structural relationship, which includes the ordinary major axis as a special case, should be preferred.
A Note Concerning Professor Jolicoeur’s Comments
Authors: Ricker W. E.
Published: April 2011

The ordinary major axis of a bivariate normal distribution is unsuitable for describing the functional relationship (in Lindley’s general sense) between two naturally variable quantities, because it is not invariant with scale and because qualitatively unlike quantities are subtracted in computing it. The bivariate structural relationship is unsuitable because one of the parameters required, λ, cannot be estimated from naturally variable data; in fact λ has no objective meaning for such data. The standard major axis (or GM regression line) has neither of these defects, and it is the line that minimizes the sum of products of the absolute vertical and horizontal deviations of data points from itself.
Biosynthesis of Lecithin by the CDP-Choline Pathway in Liver Microsomes of Rainbow Trout, Salmo gairdneri
Authors: Holub B. J. , Nilsson K. , Piekarski J. , Slinger S. J.
Published: April 2011

The enzymatic synthesis of lecithin from CDP-choline (14C) was characterized in microsomal preparations from the livers of rainbow trout (Salmo gairdneri). Optimal activity was obtained with the addition of 1,2-digylceride and Mg++ to the incubation medium. There was a 290% stimulation in cholinephosphotransferase activity when the incubation temperature was raised from 15 to 37 C. The results indicate that the CDP-choline pathway is operative in the formation of lecithin in the liver of rainbow trout. The possible function of this reaction in the acclimation offish to environmental temperature is discussed.
Mortality of Transennella tantilla Due to Burial
Authors: Gallucci Vincent F. , Kawaratani Robert K.
Published: April 2011

The mortality rates of Transennella tantilla buried under 8 cm of sediment at the 0.0 tide level and at the 0.5 m tide level were determined. After 2 days at the lower level, mortality was 74% and after 11 days, 91%. Mortality at the higher tide level after 7 day s is approximately equal to burial at the lower level after 2 days. A comparison with Venerupis japonica seed suggests that Transennella may be used as a model for the response of seed littleneck clams to burial.
Ceratomyxa shasta (Myxosporida) Disease in Chum Salmon (Oncorhynchus keta) in British Columbia
Authors: Margolis L. , Evelyn T. P. T.
Published: April 2011

Infections with the myxosporidan Ceratomyxa shasta Noble, 1950 were confirmed in four juvenile chum salmon (Oncorhynchus keta) caught at sea near Nanaimo in 1965 and 1968. These cases represent a new host record for C. shasta and a northward extension of the parasite’s known natural range. Ceratomyxosis was also presumptively diagnosed in a coho salmon (Oncorhynchus kisutch) in British Columbia.
Utilization of Wastes from Lumpfish, Cyclopterus lumpus, Roe Harvesting Operations: An Examination of the Lipid and Glue Potential, and Comparison of Meal with that from Nova Scotia-Caught Menhaden
Authors: Paradis M. , Ackman R. G. , Hingley J. , Eaton C. A.
Published: April 2011

The problem of utilization of lumpfish, Cyclopterus lumpus, wastes, generated by roe harvesting operations, was investigated. The lipid content (~2%) of female lumpfish after removal of roe is too low to result in useful commercial recovery of oil. Male lumpfish have higher lipid levels (~7.6%), but both sexes contain large amounts of water and thick collagenous skin on the head which is an unusual raw fisheries material. In a small-scale reduction process an experimental lot offish meal was produced from lumpfish with a lower yield than that obtained from other fish, but from WARF analyses appeared to be nutritionally adequate and comparable with menhaden meal produced from fish taken in Nova Scotian waters. The use of the fish skin for glue was investigated but appears uneconomic if hand skinning is required.
Benthic Organisms and the Structure of Marine Ecosystems
Authors: Mills Eric L.
Published: April 2011

The contribution of benthic ecology to biological oceanography has been relatively slight, even though the benthos may be crucial in understanding the dynamics of marine ecosystems, as J. H. Steele’s model of the North Sea indicates. Before the benthos may be accurately assigned a role in such models, we need to know at least 1) what food items are consumed and assimilated, 2) what the role of bacteria and meiobenthos may be, and 3) if there are different levels of demersal fish production from differently structured benthic communities. There seem to be no shortcuts to the kind of information about benthic animals useful in permitting assessment of fisheries production in a realistic biological framework.
Epizootiology of Tumors in a Population of Juvenile English Sole (Parophrys vetulus) from Puget Sound, Washington
Authors: Angell Charles L. , Miller Bruce S. , Wellings S. R.
Published: April 2011

An epizootic skin tumor disease affected young-of-the-year English sole (Parophrys vetulus) near Seattle, Wash. The 1969 year-class had an incidence of 18.7%. The epizootic wave began in August and peaked in October. Incidence rapidly declined thereafter. The disease coincidentally attacked winter and summer influxes. There was no difference in growth between age-group 0 normal and tumorous fish, but age distribution of tumorous fish indicated longevity differed. Tumors were more numerous on younger fish. Angioepithelial nodules grew until transforming into epidermal papillomas, which reached maximum weight in age-group II. There were no differences in sex ratios between normal and tumorous fish.
Environmental Factors Affecting the Strength of Walleye (Stizostedion vitreum vitreum) Year-Classes in Western Lake Erie, 1960–70
Authors: Busch Wolf-Dieter N. , Scholl Russell L. , Hartman Wilbur L.
Published: April 2011

Commercial production of walleyes (Stizostedion vitreum vitreum) from western Lake Erie declined from 5.9 million pounds in 1956 to 140,000 pounds by 1969. Since 1956, marked irregularity in year-class success has developed. Only four year-classes were considered good during 1959–70. The rate and regularity of water warming during the spring spawning and incubation periods in 1960–70 had a positive effect on the density of egg deposits and the resulting year-class strength. Rates of warming were not themselves detrimental, but rather the extended length of the incubation period in cool springs increased the exposure of eggs to such negative influences as dislodgment from the spawning reefs by strong current action generated by spring storms, or siltation and low oxygen tensions. The annual brood stock size had much less influence on year-class strength than did water temperature. Reproductive success was unrelated to fluctuations in size of suitable reef spawning area caused by changes in water level. Apparently the usable spawning area at any water level is more than adequate to serve the limited walleye brood stocks.
Yellow Perch (Perca flavescens) Biomass Responses to Different Levels of Phytoplankton and Benthic Biomass in Lake Memphremagog, Quebec–Vermont
Authors: Nakashima Brian S. , Leggett William C.
Published: April 2011

Perch biomass in Lake Memphremagog, Quebec was 2.5 times greater in the more productive south than in the less productive north basins. This difference is on the same order of magnitude as biomass differences in the phytoplankton (approximately 1.6×) and benthic (approximately 3×) communities. The difference in perch biomass is attributed to a larger perch population in the south basin. Growth was similar in both basins, and therefore independent of production at these lower trophic levels. Perch growth in both basins is maximal for the Quebec area and probably controlled by the length of the growing season. Abundance levels are fixed by the fourth year and possibly prior to reaching the second year of life. Perch biomass responses to different food levels in Lake Memphremagog provide empirical support to Moore’s (1941) suggestion that at abundant food levels, population size and not growth is enhanced. Previous experiments defining the relation between growth and nutrient concentration and/or primary production did not fully represent the situation in Lake Memphremagog. This may have been due to conditions in simple, controlled systems not usually found in natural, complex ones.
Quantitative Biological Assessment of the Benthic Fauna in Deep Basins of the Gulf of Maine
Authors: Rowe Gilbert T. , Polloni Pamela T. , Haedrich Richard L.
Published: April 2011

The abundance, biomass, and diversity of the macro- and mega-fauna in the deep basins of the Gulf of Maine were estimated from 41 quantitative infaunal samples and 19 visual transects made with the Deep Submergence Research Vessel (DSRV) Alvin. The homogeneous fine silt and clay (66% clay) sediments supported an infaunal abundance [Formula: see text] and wet preserved biomass [Formula: see text] which were relatively low for a continental margin (270–297 m deep) with high sediment organic carbon (1.9%). Diversity estimates (H[s]) from Alvin box core samples were lower than Alvin box core sample values from the continental slope, suggesting that the seasonally stable Gulf of Maine basins, because of their short geologic age, do not yet contain an equilibrium assemblage. An additional possibility is that seasonal variations in the production of organic matter, being more pronounced in the Gulf of Maine than offshore in deep water, affect community structure on the bottom.
Apparatus for Continuously Saturating Water with Hydrophobic Organic Chemicals
Authors: Veith G. D. , Comstock V. M.
Published: April 2011

An apparatus for generating and maintaining water solutions saturated with hydrophobic organic chemicals is described. The saturator replaces the reagent stock bottle and the organic solvents used in conventional diluters, and has ample capacity to dose large volumes of water necessary for long-term toxicology studies with aquatic organisms. The water in a constant-level reservoir is continuously saturated with the chemical by circulating the water through a bed of an inert substrate impregnated with the chemical under investigation.
Croissance de la barbue (Ictalurus punctatus) du fleuve Saint-Laurent près de Québec
Authors: Magnin Etienne , Fradette Catherine
Published: April 2011

Thin sections were made on the spiny rays of pectoral and dorsal fins of 28 channel catfish (Ictalurus punctatus) from the St. Lawrence River near Quebec City. Age determinations on these sections and the results of previous taggings gave the following length and weight growth patterns for these individuals: 200 mm and 65 g at age 3, 270 mm and 165 g at age 5, 330 mm and 310 g at age 7, 400 mm and 572 g at age 10, 530 mm and 1236 g at age 20.
Apparatus for the Quantitative Determination of Locomotor Activity Patterns of Aquatic Organisms Using Infrared Light-Emitting Diodes
Authors: Cripe Claude R. , Cripe Jesse H. , Livingston Robert J.
Published: April 2011

Photoelectric methods of measuring the activity of aquatic organisms allow unrestrained movement of the animal being studied but may disrupt exogenously controlled rhythms if the light is visible. An apparatus is described that uses infrared light-emitting diodes that eliminate some of the problems associated with incandescent light sources. A graph of the locomotor activity data of two pigfish (Orthopristis chrysoptera) which was produced by this apparatus is included.
The Early Life History of Fish.
Authors: Houde Edward D.
Published: April 2011

not available
Coupling of Land and Water Systems. Ecological Studies 10.
Authors: Dillon P. J.
Published: April 2011

not available
Review of Gillnet Selectivity
Authors: Hamley John M.
Published: April 2011

This paper reviews studies on gillnet selectivity: the relevant characteristics of fish and nets, graphical and mathematical representation of selectivity curves, and methods of estimation. F. I. Baranov started these studies 60 yr ago, and most subsequent work has been consistent with his axioms that a) gillnets catch fish whose head girths are smaller but maximum girths larger than the mesh perimeter, and b) selectivity curves for all mesh sizes have the same shapes and heights. Unfortunately these axioms are inaccurate. The heights of selectivity curves increase with mesh sizeSelectivity depends mainly on fish size and shape and mesh size, but is also affected by the thickness, material, and color of net twine, hanging of net, and method of fishing. The left slopes of selectivity curves represent smaller fish wedged in the meshes; the right slopes, larger fish mainly tangled by head parts. The curves may be very skewed or multimodal for fish that are easily tangled.The most reliable, though expensive, estimates of gillnet selectivity are by "direct" methods of fishing a population of known size-frequency distribution. The more popular but biased "indirect" estimates compare catches by two or more mesh sizes. Other methods used are prediction from girth measurements and the DeLury method.
Nitrification in an Aquatic Recirculating System
Authors: Collins M. T. , Gratzek J. B. , Shotts Jr. E. B. , Dawe D. L. , Campbell Lucy M. , Senn D. R.
Published: April 2011

Water quality changes during establishment and maintenance of nitrification in four 70-liter recirculating systems each containing 20 channel catfish (Ictalurus punctatus) (total weight 150 g) are described. Establishment of nitrification took 33 days. During establishment of nitrification, all catfish in the systems died. Death appeared to be related to nitrite concentrations greater than 2.5 mg/liter NO2-N. The pH declined with progressive nitrification. When the pH was less than 6.0, nitrification ceased. Within 2 wk of introducing the catfish, total bacterial counts stabilized at 106 organisms per milliliter. Counts of lactose fermenters and aeromonads fluctuated around 104 organisms per milliliter when fish were in the system and decreased markedly after the fish were removed. After establishment of nitrification, 40 channel catfish (total weight 100 g) were maintained successfully for 37 days.
Effects of Parasiticides on Nitrification
Authors: Collins M. T. , Gratzek J. B. , Dawe D. L. , Nemetz T. G.
Published: April 2011

Treatment of four recirculating systems with a single dose of methylene blue at 5 mg/liter resulted in complete cessation of nitrification for 16 days as evidenced by a rapid rise in ammonia and stable nitrate concentrations. The therapeutic use of methylene blue in recirculating systems is contraindicated. Treatment of the systems with therapeutic levels of formalin, malachite green, formalin and malachite green in combination, copper sulfate, potassium permanganate, and sodium chloride had no effect on nitrification.
Chemosensory Response of American Lobsters (Homarus americanus) in the Presence of Copper and Phosphamidon
Authors: McLeese D. W.
Published: April 2011

In test runways the chemosensory response of American lobsters (Homarus americanus) to herring muscle extract, applied for about 3 min, is reduced by the simultaneous presentation of copper at concentrations estimated to be 4–80 times the lethal threshold. The reduction results from avoidance of copper. Simultaneous presentation of the extract and of phosphamidon at concentrations about 2.5–100 times the lethal threshold has no effect.Exposure up to 48 h to copper at concentrations of 0.7–1.8 times the lethal threshold causes a gradual decline in chemosensory response of lobsters, followed by gradual recovery in clean water. Exposure up to 48 h to phosphamidon at concentrations of 0.7–1.8 times the lethal threshold has no effect on the response.
Proliferative Bone Lesions in Lake Whitefish (Coregonus clupeaformis)
Authors: Wobeser G. , Smith N. W.
Published: April 2011

Tumor-like masses were found attached to the skeleton in three lake whitefish (Coregonus clupeaformis) captured in two different years from Redberry Lake, Saskatchewan. The masses were composed of fibrous and osseous tissue and resembled the condition "fibrous dysplasia of bone" as described in man. There was no evidence of other disease in these fish.
Abundance and Population Dynamics of Parasites Infecting Atlantic Salmon (Salmo salar) in Trout Brook, New Brunswick, Canada
Authors: Hare G. M. , Burt M. D. B.
Published: April 2011

Ten species of parasites (8 helminth, 1 annelid, 1 mollusc) were collected from 375 juvenile Atlantic salmon (Salmo salar) in Trout Brook, N.B., during May–November 1970 and 1971. The most commonly occurring parasites were the monogenean Discocotyle sagittata (infecting 37.7% of the fish examined), the digenean Crepidostomum farionis (40.5%), the nematode Sterliadochona tenuissima (97.9%), and a glochidium (32.0%). Intensity of infection (mean number of parasites for all fish examined) of C. farionis and S. tenuissima was independent of host age and sex, and of D. sagittata was independent of age, but male salmon were more heavily infected than females. The intensity of infection of these parasites showed no interactions between host age and season nor between host sex and season. The abundance of the parasites showed marked seasonal changes: D. sagittata was most abundant in summer and autumn, C. farionis and S. tenuissima were most abundant in spring, and the glochidium was most abundant in autumn. Relationships between changes in parasite maturation and in seasonal abundance indicated annual cycles of infection.
Neuromuscular Function and Acetylcholinesterase in the Pectoral Abductor Muscle of Largemouth Bass (Micropterus salmoides) as Evidenced by the Effects of Diisopropylfluorophosphate
Authors: Schneider Jr. Phillip W. , Weber Lavern J.
Published: April 2011

The significance of acetylcholinesterase (AChE) to neuromuscular transmission in the pectoral fin abductor muscle of largemouth bass (Micropterus salmoides) was evaluated by establishing in vivo, first, the occurrence of enzyme inhibition by diisopropylfluorophosphate (DFP) and, second, the correlation between muscular response to indirect stimulation and enzyme inhibition. Dose response curves for inhibition of AChE by DFP indicated that DFP had access to and did inhibit AchE. Modification of the muscular response was observed and severity appeared to be positively correlated to AChE inhibition. The modification, however, was not typical of cholinergic systems in that the ability to produce and maintain a tetanus was never abolished even with inhibition in excess of 99% of control levels. It was concluded that AChE is not as important for neuromuscular transmission in largemouth bass as has been established for other vertebrates, and that the acute toxic effects of DFP to largemouth bass are not mediated by a collapse of neuroskeletal muscle function.
Dieldrin in the Diet of Channel Catfish (Ictalurus punctatus): Uptake and Effect on Growth
Authors: Argyle Ray L. , Williams George C. , Daniel Clara B.
Published: April 2011

Fingerling channel catfish (Ictalurus punctatus) were given diets containing 0, 0.4, 0.8, or 4.0 μg dieldrin/g of food (dry weight) for 210 days, followed by a dieldrin-free diet for 56 days. Catfish receiving 4.0 μg dieldrin/g of food gained about 17% less weight than the control fish in 210 days and about 35% less weight during the last 126 days of the 210-day period. No growth differences were attributable to the ingestion of 0.4 or 0.8 μg dieldrin/g of feed. Mortality during the experiment was random and not appreciable.Dieldrin accumulations were characterized by an immediate rapid rise of residue levels in the tissues, followed by a period during which concentrations were relatively stable. Residues in tissues decreased rapidly after dieldrin was withdrawn from the diet. Dieldrin half-life was 9.6 days (mean for the three groups).Theoretical residue concentrations calculated from the growth, feeding, and half-life data were similar to the empirical concentrations, although the theoretical values were consistently the higher. The recoverable concentration accounted for 25.7% (mean of the three treatments) of the theoretical concentration.
Evaluation of the Transplant of Pacific Pink Salmon (Oncorhynchus gorbuscha) from British Columbia to Newfoundland
Authors: Lear W. H.
Published: April 2011

Five transplants of eyed eggs of Pacific pink salmon (Oncorhynchus gorbuscha) were made between streams in southern British Columbia and North Harbour River, Newfoundland. Quantities transplanted were 0.25 million in 1959, 2.5 million in 1962, 3.4 million in 1964, 3.3 million in 1965, and 5.9 million in 1966. Adult returns from these transplants were 1, 49, 638, 8500, and 2426 during 1961, 1964, 1966, 1967, and 1968, respectively. Since 1969, returns have been the progeny of naturally spawning fish and have steadily declined in numbers. The reasons for failure of the transplant are not certain, but possibilities include the following: predation on the fry by brook trout and possibly eels in North Harbour Pond and estuary; unfavorable surface temperatures in the river during the fry run; predation by herring on fry in St. Mary’s Bay; year-class failure of the even-year stocks that were introduced; unsuitability of the donor stocks with respect to migration patterns and homing behavior; inadequate numbers of eggs were transplanted to produce populations required to maintain runs in anything below optimum environmental conditions.
Method of Determining Natural Mortality in the Northern Fur Seal (Callorhinus ursinus) from Known Pups and Kill by Age and Sex
Authors: Lander Robert H.
Published: April 2011

From known values of the number of northern fur seals, Callorhinus ursinus, born in a given year and the commercial kill of older animals of this species, by age and sex, a method is given for approximating natural mortality or survival 1) between times of birth and the first kill and 2) during the successive ages of kill. An example with hypothetical data indicates small relative error in these estimators, although bias may be considerable in certain of the associated age-specific estimators of abundance and exploitation rates. The problem of bias warrants further investigation. Estimates of natural survival from birth to the start of the kill at age 2 yr agree closely with independent tagging estimates for the 1964–66 year-classes of males from the Pnbilof Islands, Alaska. For this stock, further applications of the present method to the 1961–66 year-classes of males indicate natural survival of 31–42% during ages 0–2 yr and 84–89% annually during ages 2–5 yr.
Pleomerism, the Widespread Tendency Among Related Fish Species for Vertebral Number to be Correlated with Maximum Body Length
Authors: Lindsey C. C.
Published: April 2011

Data for 3137 fish species were analyzed for possible correlations, among related species, between mean vertebral number (V) and maximum recorded body length (L). Of 118 families having counts for over 4 species, 90 show a positive correlation; statistically significant correlations are positive in 45 and negative in only 2 families. The relationship can be expressed by the power function V = CLm, in which C and m are constants characteristic of each family or taxon. Among families with a significant correlation between V and L, the median value of m is 0.12 (representing about 10% vertebral increase for each doubling of length) but m ranges widely, from −0.033 to +0.416. Families with high mean vertebral counts tend to have high m values. The phenomenon, termed pleomerism, occurs within genera as well as within families, and sometimes between races, between populations, or even between the sexes. It exists in widely different shapes of fishes (e.g. sharks, mackerels, sea horses, sand lances, and lumpfish), and in caecilians and in sea snakes. Latitudinal gradients in vertebral number (Jordan’s rule) are often reinforced by pleomerism coupled with latitudinal gradients in maximum length, but gradients in vertebral numbers persist even when effect of maximum length is removed. Although its cause is unknown, pleomerism is taxonomically useful in predicting adult sizes of species known only from young specimens, and in unmasking synonymies of "species" based on young of other named species. Vertebral number considered in conjunction with maximum size is more reliable for making taxonomic judgments at all levels than is vertebral number alone. Moreover, if the cause of pleomerism is functional, it may provide information on locomotory mechanisms and on population biology, since mean vertebral number in each population may be matched to that body size at which selection operates most significantly.
Toxicity of 30-Minute Exposures of Residual Chlorine to the Copepods Limnocalanus macrurus and Cyclops bicuspidatus thomasi
Authors: Latimer David L. , Brooks Arthur S. , Beeton Alfred M.
Published: April 2011

The intermittent chlorination of power plant cooling waters often results in the appearance of residual chlorine in the receiving waters. Laboratory bioassays were conducted at 5, 10, 15, and 20 C to determine the toxicity of residual chlorine exposures of 30 min to the copepods Limnocalanus macrurus and Cyclops bicuspidatus thomasi. The 30-min TL-50 was 1.54 mg/liter for L. macrurus at both 5 and 10 C. For C. b. thomasi, the 30-min TL-50 values for exposures at 10, 15, and 20 C were 14.68, 15.61, and 5.76 mg/liter, respectively. The concentrations of residual chlorine causing 5% mortality (30-min TL-5) were used to predict "safe" levels for 30-min exposures. The predicted "safe" concentrations were 0.9 mg/liter for L. macrurus and 0.5 mg/liter for C. b. thomasi. These concentrations roughly coincide with the maximal chlorine levels characteristic of most power plant effluents.
Fatty Acid Levels in Developing Brook Trout (Salvelinus fontinalis) Eggs and Fry
Authors: Atchison G. J.
Published: April 2011

Changes in the fatty acid composition of the yolk and fry of developing brook trout (Salvelinus fontinalis) were analyzed. Palmitic (16:0) and docosahexaenoic (22:6) acids were characteristic of the fry and oleic (18: 1) and linoleic (18: 2) acids were selectively retained in the yolk.
Modified Lobster Traps for Catching Crabs and Keeping Lobsters Out
Authors: Stasko Aivars B.
Published: April 2011

Before redesigning lobster traps for capturing crabs and excluding lobsters, laboratory tests were done to determine the ability of both crabs Cancer irroratus and lobsters Homarus americanus to pass through simulated trap entrances and escape holes of various sizes and shapes. A long rectangular opening 44.5 mm (1.75 inches) wide allowed most crabs to enter, yet prevented passage of most legal-size lobsters. For use as escape holes in traps, round openings were found to be more effective than square ones to allow escape of lobsters while retaining commercial-size crabs.Lobster traps were then modified by closing the fishing heads and providing a long rectangular entrance at the top of the trap. Trap entrance widths of 44.5 and 51 mm (1.75 and 2.0 inches) fished crabs equally well; traps with a 38-mm (1.5-inch) entrance, and unmodified lobster traps caught fewer crabs. No lobsters were caught in the modified traps with entrance at the top.
Statistical Bias Problem in On-Site Surveys: the Severity of the Problem and its Potential for Solution
Authors: Sinclair William F. , Morley R. W.
Published: April 2011

Commercial and recreational fisheries managers often develop catch and effort estimates from information gathered in location or on-site surveys. However, a limited on-site sample cannot produce unbiased estimates of fishing effort or socioeconomic traits of the anglers unless weighting procedures are adopted to account for the varying frequencies of fishing of the fishermen. The corrective procedure involves establishing the relative probability of capturing a fisherman in the sample, then weighting the number of contacts with anglers in each frequency of use category. Unless information on the probability of including particular fishermen and fishing vessels in the sample is available the sample must be drawn with replacement.
Edema in Spawning Salmon
Authors: Hargens Alan R. , Perez M.
Published: April 2011

Salmon develop edema during their spawning migration from the sea to fresh water. As measured by the wick technique, fluid pressure in both subcutaneous and peritoneal compartments rises from negative values at sea to positive values in rivers. Concomitantly, blood colloid osmotic pressure falls during the spawning migration. Some of the degenerative changes leading to the death of postspawning salmon probably result from the total-body edema herein described.
First Occurrence of the Brook Silverside, Labidesthes sicculus, in a Tributary of Lake Superior
Authors: Berg Richard E. , Doepke Philip A. , Hannuksela Paul R.
Published: April 2011

On June 4, 1974, three brook silversides, Labidesthes sicculus, were collected by electrofishing near the mouth of the Dead River, a tributary of Lake Superior at Marquette, Michigan. This is the first record of the species in the Lake Superior watershed and it may be that the species has only recently established itself in the area.
Zinc Uptake by Atlantic Salmon (Salmo salar) Exposed to a Lethal Concentration of Zinc at 3, 11, and 19 C
Authors: Hodson Peter V.
Published: April 2011

Atlantic salmon (Salmo salar) acclimated to 3, 11, and 19 C took up high concentrations of zinc in gill tissues during exposures to a nominal 14 mg/liter of zinc. The rate of zinc uptake, as shown by 65Zn tracer, increased from a minimum at 3 C to a maximum at 19 C. In fish killed by zinc exposure, zinc concentrations in gills were highest at 19 C and lowest at 3 and 11 C.
The Salmon: Their Fight for Survival
Authors: Withler F. C.
Published: April 2011

not available
The Inland Waters of Tropical Africa. An Introduction to Tropical Limnology.
Authors: Fryer Geoffrey
Published: April 2011

not available
Light’s Manual: Intertidal Invertebrates of the Central California Coast. Third edition.
Authors: Kozloff Eugene N.
Published: April 2011

not available
Optimal Exploitation of Multiple Stocks by a Common Fishery: A New Methodology
Authors: Hilborn R.
Published: April 2011

Optimal harvest rates for mixed stocks of fish are calculated using stochastic dynamic programming. This technique is shown to be superior to the best methods currently described in the literature. The Ricker stock recruitment curve is assumed for two stocks harvested by the same fishery. The optimal harvest rates are calculated as a function of the size of each stock, for a series of possible parameter values. The dynamic programming solution is similar to the fixed escapement policy only when the two stocks have similar Ricker parameters, or when the two stocks are of equal size. Normally, one should harvest harder than calculated from fixed escapement analysis.
Chronic Effects of Reduced pH on Brook Trout (Salvelinus fontinalis)
Authors: Menendez Raymond
Published: April 2011

During an 11-mo period all developmental stages of the brook trout (Salvelinus fontinalis) were continuously exposed to pH levels of 4.5, 5.0, 5.5, 6.0, 6.5, and the control 7.1. The number of viable eggs was reduced significantly at pH 5.0 and to a lesser extent at the higher pH levels. Embryo hatchability was significantly less at all pH levels below 6.5. Growth and survival of alevins was reduced at the lower pH levels. These data indicate that continual exposure to pH values below 6.5 will result in significant reductions in egg hatchability and growth.
Short-Term Serum Prolactin Concentrations in Goldfish (Carassius auratus) Subjected to Serial Sampling and Restraint
Authors: Spieler Richard E. , Meier Albert H.
Published: April 2011

Serum prolactin concentrations in serially sampled goldfish (Carassius auratus) did not vary significantly between 30 s and 3 min after initial capture. A marked decrease in prolactin concentration was noted 9–17 min after initial capture followed by a recovery at 30–48 min. Although there was a circadian variation in prolactin concentration, the pattern of response to capture and sampling did not vary significantly among the times tested.
Acute Toxicity of Sodium Chloride, Pentachlorophenol, Guthion®, and Hexavalent Chromium to Fathead Minnows (Pimephales promelas) and Goldfish (Carassius auratus)
Authors: Adelman Ira R. , Smith Jr. Lloyd L. , Siesennop Gary D.
Published: April 2011

The 96-h LC50’s for sodium chloride were 7650 and 7341 mg/liter, for pentachlorophenol 0.21 and 0.22 mg/liter, for Guthion® 1.9 and 2.4 mg/liter, and for hexavalent chromium 48 and 120 mg/liter, for fathead minnows (Pimephales promelas) and goldfish (Carassius auratus), respectively. Threshold LC50’s were reached in 6 days for sodium chloride (7650 and 7322 mg/liter for fathead minnows and goldfish, respectively), and pentachlorophenol (0.21 and 0.21 mg/liter), but were not attained in 11 days (termination of testing) with Guthion® (0.76 and 0.80 mg/liter) and hexavalent chromium (18 and 33 mg/liter). With pentachlorophenol and Guthion® goldfish were initially more resistant, but by termination there was no significant difference in LC50’s between the two species. With hexavalent chromium the goldfish were more resistant throughout the 11-day test, and with sodium chloride goldfish were initially more resistant but at attainment of a threshold LC50 were less resistant. Use of toxicity curves for assessment of acute mortality permits interpretation not possible in 96-h tests where LC50’s are computed at 24-h intervals.
Primary Production, Extracellular Release, and Heterotrophy in Two Lakes in the ELA, Northwestern Ontario
Authors: Nalewajko C. , Schindler D. W.
Published: April 2011

During short-term experiments with phytoplankton, excretion rates of 14C labeled organic substances may change without concomitant changes in photosynthetic rates. Percentage extracellular release (p.e.r.) values generally decreased with time.In eutrophic Lake 227, p.e.r. after 3-h incubation ranged from about 1 to 4%, depending on light intensity, when phytoplankton biomass was high, but the range was from about 7 to 15% at a time of low biomass. In oligotrophic Lake 239 p.e.r. was about 20%. Mainly large molecules, exceeding 1500 mol wt, were excreted by phytoplankton. A tracer bioassay gave significantly lower estimates of acetate and glucose concentrations than the Michaelis–Menten analysis. Extracellular release rates of dissolved organic compounds by phytoplankton exceeded the total heterotrophic uptake rates of acetate, glucose, and glycollate.
Ecology of Chironomidae (Diptera) in a Polar Lake
Authors: Welch H. E.
Published: April 2011

The six common genera of Chironomidae (Diptera) in Char Lake, Resolute, Northwest Territories (74°42′N lat.) were studied intensively from 1969 to 1972. Heterotrissocladius oliveri and a Trissocladius species are characteristic of the sediment zone, while two species of Orthocladius, Pseudodiamesa arctica, Paracladius quadrinodosus, and Lauterbornia sp. are restricted mainly to the rocky and moss zones. Life cycles are 2 or 3 yr, depending upon the species. Year-classes could be discriminated by instar frequency distribution. Populations increased steadily during the study period, for an average increase in strength of 5 times between the 1968 and 1971 year-classes. Summer emergence and egg-laying conditions are of overriding importance to year-class strength. Mortality within year-classes is undetectable until the last 4 mo of larval life, when mortality due to char predation is about 65% between April and the time of emergence. The physiology of these chironomids does not seem unusual aside from continuing activity down to 0 C, and there is no indication of metabolic compensation. Net growth efficiency averages 36%. Assimilated energy (growth + respiration) at 8.6 kcal m−2 yr−1 is very low compared with temperate zone populations, but is more similar as a percent of photosynthesis, 4.1%. The relatively large detritus pool and the presence of both 2- and 3-yr species tend to stabilize chironomid energy flow. Definition of long-term averages for chironomid populations in Char Lake would require a decade or more of study.
Low Thermal Responsiveness in the Bluegill, Lepomis macrochirus
Authors: Beitinger Thomas L. , Magnuson John J.
Published: April 2011

Fifteen young bluegill, Lepomis macrochirus, acclimated to 5 C for at least 1 mo, died during temperature preference testing owing to apparent voluntary exposure to high temperatures. The mortality rate of 100% for these fish greatly exceeded the 3.8% rate found for 262 bluegill acclimated to temperatures ranging from 20 to 34 C, and tested in the same apparatus. Modifications in the experimental design whereby fish acclimated to 5 C were held at about 19 C for 24 h during testing, enabled all fish to survive. These bluegill selected temperatures only 2 C lower than those acclimated to summer conditions.
Scope for Metabolism and Growth of Sockeye Salmon, Oncorhynchus nerka, and Some Related Energetics
Authors: Brett J. R.
Published: April 2011

The extent of metabolic and feeding requirements for fingerling sockeye salmon (Oncorhynchus nerka) are compared over the tolerable range of temperature. Scope for growth, derived from the difference between maximum and maintenance rations, is shown to relate to temperature in a manner similar to that for maximum growth rate. Metabolic scope is compared with scope for growth, supporting the general concept of scope for activity developed by Fry (1947).
Seasonal Mortality of Rainbow Trout (Salmo gairdneri) Planted in Small Eutrophic Lakes of Central Canada
Authors: Ayles G. Burton , Lark J. G. I. , Barica J. , Kling Hedy
Published: April 2011

The seasonal mortality pattern and the causes of the mortality of planted rainbow trout (Salmo gairdneri) were studied in eight small eutrophic lakes in central Canada used for extensive aquaculture. Two periods of mortality were revealed. The first occurred in all lakes during the first 60 days of residence in the lakes and resulted in the mortality of 60–90% of the numbers of fish stocked. The second period occurred in about 20% of the lakes and was due to low oxygen levels following the collapse of a bloom of Aphanizomenonflos-aquae. Rainbow trout are close to their physiological upper tolerance levels in these lakes. Possible environmental and biological causes of mortality during the first period are discussed.
Electrophysiological Studies of Morpholine-Imprinted Coho Salmon (Oncorhynchus kisutch) and Rainbow Trout (Salmo gairdneri)
Authors: Cooper Jon C. , Hasler Arthur D.
Published: April 2011

Two groups of coho salmon (Oncorhynchus kisutch) were exposed to a 5 × 10−5 mg/liter concentration of a synthetic chemical, morpholine, for 4 wk during the smolting period, while two corresponding groups were left unexposed (controls). All groups were marked by finclipping and stocked into Lake Michigan near the mouth of Oak Creek (South Milwaukee, Wisconsin). A second series of exposed and unexposed salmon was released 13 km north of Oak Creek. Rainbow trout (Salmo gairdneri) were tested in a similar experiment.Homing salmonids were censused and then used in physiological experiments. Electroencephalographic studies showed significantly greater responses by the experimental (exposed) compared to control fish to 1% morpholine (P ≤ 0.001 − 0.05) and by one paired group to a stream sample scented with morpholine (about 10−3 mg/liter morpholine P ≤ 0.01). Responses to morpholine were specific in that another chemical similar to it did not elicit responses. These data support the olfactory hypothesis that salmon may imprint to naturally occurring homestream odors in the same way as they do to morpholine.
Salinity Effects on Plasma Electrolytes of Channel Catfish, Ictalurus punctatus
Authors: Davis Kenneth B. , Simco Bill A.
Published: April 2011

Plasma sodium and chloride levels of channel catfish (Ictalurus punctatus) increased after a 5-day exposure to 10 and 12 g/liter sodium chloride. Exposure of fish to 4 and 8 g/liter for 5 days resulted in plasma electrolyte levels higher than those of fish kept in aged tap water, but were not different from values usually found in freshwater fish. These observed differences may have been due to handling. Tests were performed during several months and no effect due to season was observed.When fish in July (27 C) were exposed to 10 g/liter sodium chloride, the plasma electrolyte concentration increased for 48 h and then stabilized. Exposure to the same concentration in March (9 C) resulted in a slow increase of plasma electrolytes throughout the 13 days of the experiment. Injection of 100 μg/kg cortisol had no effect on plasma electrolyte increase during 48 h after transfer to 12 g/liter sodium chloride.