bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct and Indirect Effects of Oil on Ringed Seals (Phoca hispida) of the Beaufort Sea
Authors: Geraci Joseph R. , Smith Thomas G.
Published: April 2011

Ninety-six ringed seals (Phoca hispida) were taken from nets at Brown’s Harbour, Northwest Territories in the fall of 1974. Comparison with two other net samples from 1971 and 1972 revealed a lower proportion of young-of-the-year and a lower mean weight of seals in all age-classes. Six seals immersed in Norman Wells crude oil for 24 h at the field netting site suffered only transient eye problems and minor kidney and possibly liver lesions; no permanent damage was observed. Three seals transported to the University of Guelph all died within 71 min after oil was introduced into their pool. Hematologic and blood chemical studies indicate that death was caused by oil superimposed on the stress of captivity. Six, 3–4 wk-old wild whitecoat harp seal (P. groenlandica) pups at the Magdalen Islands, Quebec, were coated with crude oil. No significant differences in core body temperatures were noted and no deleterious effects were observed. Five captive ringed seals at Guelph were subjected to a cumulative dosage of Norman Wells crude oil fed with their fish food. High dosage (75 ml) and low dosage (25 ml) of crude oil were also fed to two groups of six harp seal pups. No significant lesions or behavioral changes were noted. These experiments were of an acute nature and reflect the effects of a brief contact with oil only. Effects of longer contact as would probably be the case in an offshore oil well blowout situation are discussed. Possible effects of large-scale offshore oil fields are also considered.
Subsurface Currents in the Strait of Georgia, West of Sturgeon Bank
Authors: Chang P. , Pond S. , Tabata S.
Published: April 2011

Spectral characteristics of subsurface currents and temperature records spanning 310–533 days from the Strait of Georgia near Sturgeon Bank are examined. Of particular interest are low-frequency fluctuations having a characteristic period of 30 days. Typically, the energy of the low-frequency and tidal currents are equal at 50 m (each about 40% of the total) and 10 and 70%, respectively, at 200 m.Low-frequency currents are observed to be baroclinic and possess a lateral length scale < 10 km. Their generation mechanisms are not identified. Low-frequency fluctuations in sea level and current have poor-to-fair coherence, while those in air pressure and current have poor coherence. Low-frequency fluctuations in wind and current have fair coherence at the eastern mooring and poor coherence at the remaining two moorings.Fluctuations in water temperature have a characteristic period of 300 days. Water temperatures at different locations generally have poor coherence except at the lowest frequencies where they are fair to good. Water temperature and current at the same location have poor coherence.Tidal currents are found to be ellipses, with the largest constituents being M2 and K1. The magnitude, shape, and orientation of the tidal current ellipses are time-dependent. Internal tides are suggested as an explanation.
Storm Surges in the Southern Beaufort Sea
Authors: Henry R. F. , Heaps N. S.
Published: April 2011

Evidence of storm surge occurrence in the Canadian sector of the southern Beaufort Sea is reviewed and distinctions are drawn between surges occurring in the absence and presence of ice cover. Two numerical models are described, one intended for detailed simulation of past surges, the other a compact, economical model designed for operational forecasting of surges. The associated system used to obtain the required wind-stress input to the numerical models is also discussed.
Residue Dynamics of Di-2-ethylhexyl Phthalate in Fathead Minnows (Pimephales promelas)
Authors: Mayer Foster L.
Published: April 2011

Fathead minnows (Pimephales promelas) were continuously exposed to 1.9–62 μg/liter di-2-ethylhexyl phthalate (DEHP) for 56 days. The accumulation factors ranged downward from 886 to 155 as the exposure concentrations increased. The major metabolite of DEHP was the monoester, 2-ethylhexyl phthalate. After being placed in uncontaminated water, the fish eliminated half of the DEHP in 12.2 days.
Development of Atlantic Salmon (Salmo salar) Eggs and Alevins Under Varied Temperature Regimes
Authors: Peterson R. H. , Spinney H. C. E. , Sreedharan A.
Published: April 2011

Atlantic salmon (Salmo salar) eggs and alevins were raised under conditions where the temperature was systematically varied either at fertilization, at the eyed egg stage, or at hatching. Mortality was more than 20% in eggs started immediately after fertilization at constant incubation temperatures < 4 °C as compared with 5% or less at temperatures > 4 °C. Alevins that eyed at 8 °C and higher were progressively smaller the higher the temperature. The optimum temperature from fertilization to eye pigmentation was near 6 °C. Eyed eggs reared at lower temperatures until hatching were larger than those hatched at higher temperatures. This size differential was maintained until the yolk was completely absorbed at all posthatching temperatures investigated. Sudden decreases in temperature at the eyed egg and hatching stages induced severe edema of the alevin yolk sac, resulting in slower growth and increased mortality.
Encounter Probabilities and Community Structure in Zooplankton: a Mathematical Model
Authors: Gerritsen Jeroen , Strickler J. Rudi
Published: April 2011

Predator–prey interactions between swimming animals of the zooplankton are studied in a mathematical model. The assumptions are: 1) the animals are points in a 1-m3 homogeneous space, 2) the animals move at random and are randomly distributed, and 3) the predator animal has an encounter radius given by its sensory system. The mathematics of encounter probabilities are developed for a 3-dimensional space. The results show two optimal strategies: 1) cruising predators which prey upon slow moving animals (herbivores), and 2) ambush (nonmoving) predators which prey upon fast cruising prey. Of the variables used (population densities, speeds of the two animal species, and encounter radius) the encounter radius has the greatest influence on the encounter probabilities. The results suggest a simple community structure and point to the importance of studies on live zooplankton.
New Cell Line from the Marine Lumpfish, Cyclopterus lumpus
Authors: Li M. F. , Clyburne S.
Published: April 2011

A cell line was grown from fin tissue of lumpfish (Cyclopterus lumpus). The cells were propagated in RTO medium supplemented with NaCl at 18 °C and have a generation time of 108 h. They are fibroblast-like, contain numerous cytoplasmic granules, are susceptible to amphibian virus (LT-1), and have an average chromosome number of 2N = 50.
Seasonal and Developmental Variation in the Lethality of Zinc to Juvenile Atlantic Salmon (Salmo salar)
Authors: Zitko V. , Carson W. G.
Published: April 2011

The incipient lethal level (ILL) of zinc to juvenile Atlantic salmon (Salmo salar) in fresh water at a water hardness of 14 mg/ℓ varies from 150 to 1000 μg/ℓ as a function of season and developmental stage of the fish. The ILL increases from 500 to 1000 μg/ℓ during the 1st yr and decreases to 150 μg/ℓ in the following spring. The more sensitive stage in the salmon's life history, evidenced by decrease of ILL coincides with and is probably related to initial stages of the parr–smolt transformation.
Morphological Development of the Integument of the Sea Lamprey, Petromyzon marinus
Authors: Anderson William C. , Manion Patrick J.
Published: April 2011

The thickness of the ventral body wall of the sea lamprey (Petromyzon marinus) increased 117% from June through January, and decreased 14% from January through May. During these respective periods, length increased 93% and decreased about 11%. Our studies suggest that the loss in length is part of the natural cycle; possibly prespawning adults cease feeding, or feed at a greatly reduced rate, beginning as early as January, rather than in March or April, as previously believed.
Factors in Interpreting Data Obtained by Diel Sampling of Fish Stomachs
Authors: Eggers Douglas M.
Published: April 2011

A simple differential equation model describing the level of food in the stomach, incorporating simultaneous ingestion and gastric evacuation, is used to gauge the sensitivity of methods that utilize diel change in food level of the stomach to determine diel feeding activity of fish. Analysis of model behavior under different feeding regimes shows that diel pattern of food level in the stomach is less sensitive to feeding regime than many authors claim.An expression is derived for the magnitude of bias associated with cessation of feeding and continuance of gastric evacuation while fish are retained by the fishing gear. This bias may be reduced by minimizing sampling time and accelerating preservation of captured fish in experiments to determine feeding chronology and daily ration.
Host and Seasonal Associations of Echinorhynchus salmonis (Acanthocephala: Echinorhynchidae) in Lake Michigan Fishes
Authors: Amin Omar M. , Burrows Janet M.
Published: April 2011

Echinorhynchus salmonis Müller was the dominant intestinal parasite infecting 14 species of southwestern Lake Michigan fishes. New host records are reported for chinook salmon, Oncorhynchus tshawytscha, and slimy sculpin, Cottus cognatus. Infections were heaviest in members of the Salmonidae. Host–parasite relationship in smelt was most closely analyzed. No pronounced seasonal periodicity in the rate and intensity of infection or worm maturation was observed. Recruitment and maturation occurred throughout the year but were, however, enhanced by colder and warmer temperatures, respectively. Sex ratio was nearest to even in winter. Fifty percent or more of worms were localized in the posterior-most region of host intestine and posterior migration with maturation was indicated. Heavier infections were noted in larger (older) fishes. Alternative routes of infection of the larger piscivorous salmonids via transfer hosts are suggested. Female hosts were more heavily infected than males. Echinorhynchus salmonis was not shown to seriously threaten its host's health or survival.
Resting Eggs in Pontella meadi (Copepoda: Calanoida)
Authors: Grice George D. , Gibson Victoria R.
Published: April 2011

Pontella meadi Wheeler produces resting eggs in fall which hatch the following summer. Experiments show that these eggs require 4–8 wk of incubation at 2–3 or 5–6 °C for substantial hatching to occur. Eggs occur in sediment in winter. Resting eggs serve to repopulate temperate inshore areas with this species after its winter disappearance from the plankton. Key words: Copepoda, Calanoida, Pontella, resting eggs, incubation time, distribution
Evaluation of Erythrocyte δ-amino Levulinic Acid Dehydratase Activity as a Short-Term Indicator in Fish of a Harmful Exposure to Lead
Authors: Hodson Peter V. , Blunt Beverley R. , Spry Douglas J. , Austen Keith
Published: April 2011

The activity of erythrocyte δ-amino levulinic acid dehydratase (ALA-D) of fish is easily measured under a variety of experimental conditions. Exposure of rainbow trout (Salmo gairdneri), brook trout (Salvelinus fontinalis), goldfish (Carassius auratus), and pumpkinseeds (Lepomis gibbosus) to lead consistently inhibited ALA-D within 2 wks at concentrations as low as 10, 90, 470, and 90 μg/ℓ, respectively. In rainbow and brook trout these concentrations were closely related to the published minimum effective concentrations causing sublethal harm. There was a significant linear relationship between ALA-D activity and log of blood lead concentration, between ALA-D activity and log of lead in water, and between blood lead and lead in water. Near lethal exposures to cadmium, copper, zinc, and mercury did not significantly inhibit ALA-D activity. Recovery of ALA-D activity of rainbow trout after transfer from 120 μg/ℓ lead to clean water occurred in 8 wk. This enzyme provides fast, consistent, specific, and sensitive estimates of lead concentrations causing sublethal harm to fish and may help to relate sources of lead to degree of exposure of fish populations in the field. Key words: lead, sublethal toxicity, fish, indicator enzyme, δ-amino levulinic acid dehydratase
Effects of a Parasite, Eubothrium salvelini (Cestoda: Pseudophyllidea), on the Resistance of Juvenile Sockeye Salmon, Oncorhynchus nerka, to Zinc
Authors: Boyce Norbert P. , Yamada S. Behrens
Published: April 2011

Most research to date on the tolerance of natural populations to physical and chemical stressors appears to have overlooked that parasites may themselves be stressors, and that they may be capable of modifying the resistance of the host to other applied stressors. Sockeye salmon (Oncorhynchus nerka) smolts trapped at the outlet of Babine Lake, central British Columbia, were subjected to 1 mg/ℓ dissolved zinc under laboratory conditions. Smolts infected with the intestinal cestode Eubothrium salvelini proved to be significantly more susceptible to zinc than were noninfected smolts. We recommend that future investigations of environmental effects, especially on wild populations, include consideration of the state of parasitism of the test organisms. Key words: Eubothrium salvelini, cestode, sockeye salmon, Babine Lake, zinc, toxicity
Repeat Homing of Brown Trout (Salmo trutta) in Lake Eucumbene, New South Wales, Australia
Authors: Tilzey R. D. J.
Published: April 2011

Spawning runs of lentic-dwelling brown trout (Salmo trutta) and rainbow trout (S. gairdneri) in Swamp Creek, an inlet of Lake Eucumbene, were studied for 4 consecutive yr, and 3517 browns and 415 rainbows were tagged during 1968–70. A further 240 browns and 229 rainbows were marked in other inlets. Recaptures of marked browns in 1969 and 1970 showed a high incidence of repeat homing, up to 25.7 and 10.6% returning after 12 and 24 mo, respectively. Few rainbow trout homed. Tag loss and the mortality and maturation of marked browns were estimated and percentage homing and straying in 1969, 1970 and 1971 was calculated. High percentage homing [Formula: see text] in 1969–70 and the variance in external form in the lentic population suggested some genetic isolation within the brown trout population. Homing ability was not influenced by fish age. Percentage homing fell markedly in 1971 after the removal of nearly all resident brown trout from Swamp Creek and suggested racially distinct stream trout populations to be an important navigational cue to homing brown trout. Key words: repeat homing, Salmo trutta, homing frequency, navigation, racial cue, Australia
Uptake and Clearance of Petroleum Hydrocarbons in the Ringed Seal, Phoca hispida
Authors: Engelhardt F. Rainer , Geraci Joseph R. , Smith Thomas G.
Published: April 2011

Ringed seals, Phoca hispida, showed rapid absorption of hydrocarbons from Norman Wells crude oil into body tissues and fluids when exposed by both immersion and ingestion. Relatively low but significant levels were found in tissue, blood, and plasma. Levels in bile and urine were high, indicating these to be routes of excretion. Key words: petroleum, hydrocarbons, benzene, ringed seal, immersion, ingestion, uptake, clearance
Analysis of Zooplankton Population Fluctuations in the Strait of Georgia, British Columbia
Authors: Gardner Grant A.
Published: April 2011

Canonical correlation, cluster, multiple regression, factor, and principal component analyses were used to examine zooplankton and hydrographic data over the period of unusual fluctuations in the overwintering population sizes of Calanus plumchrus, C. marshallae, and C. pacificus in the Strait of Georgia. Additional hydrographic data were examined for relationships between physical and biological data 3 and 6 mo out of phase. Analysis indicates a recent subtle temperature and salinity shift of uncertain biological significance. Canonical correlation and principal component analyses suggest that 15% of the variance in the zooplankton is related to a temporal trend paralleling that seen in the physical characteristics of the environment.Based on the factor analysis, C. plumchrus, Pseudocalanus minutas, Acartia longiremus, Sagitta elegans, Euphausia pacifica, Limacina spp, and Oithona spinirostris are suggested as "key" species for future zooplankton monitoring programs. Statistically supported species selection can reduce the time and expense of sorting zooplankton samples without an equivalent reduction of information yield. Key words: zooplankton, populations, Calanus, statistical analysis, temporal trends
Population Differences in Rainbow Smelt, Osmerus mordax: Multivariate Analysis of Mensural and Meristic Data
Authors: Copeman D. G.
Published: April 2011

The phenetic relationships are investigated between 13 samples of sexually mature rainbow smelt, Osmerus mordax, from 12 collecting sites including representatives of anadromous and landlocked populations. Data on 32 mensural and meristic characters were obtained. Univariate and multivariate analyses revealed that the samples fell into three distinct groups composed of the anadromous, normal freshwater, and stunted freshwater populations. Mean values of the mensural and some meristic characters decreased across these three groups; some other meristics increased. It is doubtful whether the magnitude of the observed meristic variation represents solely a plastic environmental response.The two freshwater stunted samples were 100% separable from the freshwater normal and anadromous samples using all the data, and 92.5 and 97.5% separable using one (total gill rakers) and all meristics, respectively. The identification success and other published biological data indicate that they fulfill the criteria for species recognition.Between anadromous and normal freshwater groups 99.2% correct identification was achieved when all data were used. Using only one and two meristics (total gill rakers and total vertebrae), 89.1 and 91.4% correct identification was achieved, which suggests subspecific status for these two groups.When the freshwater normal and anadromous groups were analyzed separately, more variation was seen within the freshwater group. Evidence of year-to-year variation was seen from the analysis of the anadromous samples and evidence for a genetic basis is presented. Key words: Osmerus mordax, population, anadromous, freshwater stunted, variation, meristic, multivariate, taxonomy
Zooplankton Fixation and Preservation.
Authors: Low C. J.
Published: April 2011

not available
Review of Underwater Biotelemetry, with Emphasis on Ultrasonic Techniques
Authors: Stasko A. B. , Pincock D. G.
Published: April 2011

Underwater biotelemetry includes studies of movements, behavior, and physiological functions of underwater animals, as well as environmental conditions surrounding them. In such studies data are received via signals from a transmitter on or in an animal. Ultrasonic signals were used in early work. More recently both ultrasonic and radio signals have been used.In the two decades since the first underwater biotelemetry studies in the mid-1950s there have been considerable technical advances. Transmitters have become smaller, more powerful, and have longer operating life. Coding of individual transmitters has become more reliable and decoding more automated. Transmitters capable of sensing environmental, behavioral, and physiological factors from free-swimming animals have been built. Receiving systems ranging from small ones for tracking from canoes to large ones for oceangoing vessels have been developed.With this equipment about 60 species of underwater animals have been studied. Various techniques of transmitter attachment have been developed and different methods of tracking explored.Underwater biotelemetry has been applied to studies of fish migration, orientation mechanisms, movement patterns at obstructions, ecology, behavior, and physiology of animals. Key words: telemetry, underwater biotelemetry, tracking, sonic tags, transmitters, receivers, hydrophones
Ocean Migration Rates of American Shad (Alosa sapidissima)
Authors: Leggett William C.
Published: April 2011

Ocean migration rates of American shad (Alosa sapidissima), estimated from tag returns, averaged 21 km/day during the spring northward migration along the Atlantic coast between Chesapeake Bay and the Bay of Fundy and appear to be regulated by temperature preferences of the species. The fall southward migration is believed to occur at a similar rate. An evaluation of known saltwater swimming speeds and of prevailing currents along the migratory path indicates that the distance traveled during the northward and southward migrations may exceed the minimum distance route by up to 100 and 500%, respectively, and suggests that considerable nondirected movement may occur. The sustained swimming speeds of juvenile shad at the time of their entry into the sea are close to the estimated minimum sustained speeds required to complete the initial migration in the sea. Annual density-dependent variation in individual growth rate, through its influence on size at emigration and the resulting swimming performance of juveniles, may significantly influence juvenile survival. Key words: American shad, Alosa sapidissima, migration rates, swim speeds, survival
Treatments Before Frozen Storage Affecting Thaw Drip Formation in Pacific Salmon
Authors: Bilinski E. , Jonas R. E. E. , Lau Y. C. , Gibbard G.
Published: April 2011

Freshly caught chum salmon, Oncorhynchus keta, were stored in ice or refrigerated seawater for 0.3 and 10 days and were then gutted and frozen at two different rates (1 or 14.5 h through the temperature range of 0 to −5 °C). The amount of thaw drip (TD) was determined in steaks following 1.5, 4, 8, and 12 mo of storage at −28 °C. A significant increase in TD occurred with the slow freezing rate or with a delay before freezing. These effects were not suppressed by a prolonged frozen storage, which also produced an increase in TD. There was no marked difference between fish held in ice and refrigerated seawater before freezing. Similar results were obtained with coho salmon, O. kisutch, frozen without prior chill stowage. Key words: Pacific salmon, thaw drip, chill stowage, freezing rates Oncorhynchus keta, O. kisutch
Observations on Three Species of Baleen Whales off Northern Newfoundland and Adjacent Waters
Authors: Perkins Judith , Whitehead Hal
Published: April 2011

Minke, Balaenoptera acutorostrata, finback, Balaenoptera physalus, and humpback whales, Megaptera novaeangliae, were observed off northern Newfoundland and southern Labrador between June and September 1975, principally from a sailing boat. Distributions for these species are recorded and correlated with water depths and distances from shore. Several isolated sounds, but no "songs," were recorded from humpback whales in Notre Dame Bay, where a population estimate was calculated based on a new method of photographic marking of individuals. Key words: baleen whales, geographical distribution, population size, photographic tagging
Retinal Structure and Function in the Walleye (Stizostedion vitreum vitreum) and Sauger (S. canadense)
Authors: Ali M. A. , Anctil M.
Published: April 2011

In the sauger, Stizostedion canadense, the tapetum lucidum of the retina was found to be more highly developed than in the walleye, S. vitreum vitreum. The tapetum is uniformly distributed throughout the sauger's eye, whereas it reaches a comparable development only in the ventral region of the walleye's retina. Other structural differences also suggested that the sauger's retina is more sensitive to light than the walleye's. In both species, photomechanical changes in response to light- and dark-adaptation were restricted to the retinal epithelial pigment (melanin) and the rods. Electroretinographic recordings appeared to be correlated with the differences in tapetal development and habits of the two species. Key words: Percidae, Stizostedion vitreum vitreum, S. canadense, light intensity, retinal structure, histology, electrophysiology, behavior
Changes in Walleye (Stizostedion vitreum vitreum) Population in Rainy Lake and Factors in Abundance, 1924–75
Authors: Chevalier J. R.
Published: April 2011

Annual commercial harvests of walleye (Stizostedion vitreum vitreum) from Rainy Lake steadily declined from 150,000 kg in the 1920s to 19,000 in the early 1970s; total (all species) harvests averaged 374,000 kg from 1924 to 1975, 45% greater than the MEI estimated allowable harvest. The walleye catch per unit of effort from commercial 102 mm gill nets declined from 43.63 kg/km in 1948 to 18.43 in 1969. Growth rate of walleye increased from 1959 to 1965, probably as a compensatory response to decreased abundance. The increased growth rate, in conjunction with heavy exploitation, caused the mean age of the walleye commercial catch to decline from 1957 to 1967. Both spring water levels and brood stock abundance were significant factors in walleye abundance 5 yr later. From multiple linear regression analysis, these two variables accounted for 65% of the variation in commercial walleye CUE. Key words: Percidae, Stizostedion, walleye, population dynamics, abundance, yield, exploitation, water level, Rainy Lake, Ontario–Minnesota
Changes in Yellow Perch (Perca flavescens) Populations of Lake Michigan, 1954–75
Authors: Wells LaRue
Published: April 2011

In the early and mid-1960s the abundance of yellow perch (Perca flavescens) in Lake Michigan declined abruptly. The decline began in the northern part of the lake and spread progressively southward. Circumstantial evidence suggests that the nonnative alewife (Alosa pseudoharengus), by interfering with perch reproduction, was the primary cause of the decline. The alewife was first reported in northeastern Lake Michigan in 1949, and had become extremely abundant throughout the lake before an enormous die-off in 1967 reduced its numbers by an estimated 70%. An intensive fishery hastened the decline of perch. In most areas the decline was immediately preceded by a period of conspicuously high commercial production. This high production appears to have been related in part to increased growth rates of perch resulting from much lower density of younger fish. A sport fishery for perch in shallow water collapsed a few years before the species declined in abundance. The most logical explanation is that heavy concentrations of alewives physically displaced the perch from nearshore areas. Although perch populations increased in some areas in the 1970s, a full recovery is unlikely unless alewife numbers are further reduced. Key words: Percidae, Lake Michigan, Perca, population dynamics, exploitation, competition
Evidence for the Presence of a Metamorphic Check in Capelin (Mallotus villosus) Otoliths and Implications for Age Determination
Authors: Bailey R. F. J. , Able K. W. , Leggett W. C.
Published: April 2011

The otolith method of aging capelin (Mallotus villosus) from the estuary and western Gulf of St. Lawrence was validated. Hyaline zones are deposited annually in the late fall and winter and thus can be used in age determination. Back-calculated mean length at the first hyaline zone corresponded well with the average length of capelin larvae collected in November and this zone is interpreted as the first annulus. The mean size at the second hyaline zone corresponded exactly with the length at which capelin undergo a profound metamorphosis. This second hyaline zone, which is laid down in the summer of the 2nd yr, was thus interpreted to be a metamorphic check. The third hyaline zone, deposited at a mean length of 95 mm, which corresponded with the peak in the length frequency distribution (when allowance was made for growth), was interpreted as the second annulus. Analysis of two otolith aging techniques currently used suggests that the "Newfoundland" method misinterprets the metamorphic check as the first annulus, rejecting the true first annulus as a "larval check,” a feature having no biological basis in fact. This results in correct ages, but estimates of lengths at the first annulus are exaggerated. The "Greenland" or "Danish" method may misinterpret the metamorphic check as the second annulus thereby resulting in erroneous ages. Key words: capelin, Mallotus villosus, otoliths, age verification, Gulf of St. Lawrence
Movements of Stream-Resident and Anadromous Arctic Char (Salvelinus alpinus) in a Perennial Spring on the Canning River, Alaska
Authors: Craig P. C.
Published: April 2011

Perennial springs in arctic drainages are used extensively by freshwater-resident and anadromous segments of Arctic char (Salvelinus alpinus) populations. Movements of these fish were monitored in a small spring on the Canning River from May 23 to October 7, 1973, dates approximating spring breakup and winter freeze-up in the drainage. Char passing through the weir ranged in size from 22-mm fry to 595-mm anadromous spawners, though most fish were juveniles measuring 60–200 mm. The spring channel was utilized as (1) a spawning area for anadromous spawners and residual males in autumn, (2) a rearing area for fry and some older juveniles in summer, and most importantly (3) an overwintering area for juvenile char, especially those in their first and second winters of life. Key words: Arctic char, movements, spawning, overwintering, growth, perennial springs, Alaska, arctic
Relation Between Temperature and Incubation Time for Eggs of Chinook Salmon (Oncorhynchus tshawytscha)
Authors: Alderdice D. F. , Velsen F. P. J.
Published: April 2011

With data assembled from the literature, relations are examined between incubation temperature and rate of development from fertilization to hatching for chinook salmon (Oncorhynchus tshawytscha) eggs. Ten forms of three empirical relations are used, based on the thermal sums hypothesis, Bělehrádek's equation, and a form of the logistic curve. In each case comparisons are made using constant, ambient, and combined (constant + ambient) incubation temperatures. In most cases the rules of minimum variance curve fitting are somewhat violated, although results using the log-inverse form of Bělehrádek's equation are superior to those from the other models. Early imposition of low, constant incubation temperatures (below 6–7 °C) appears to slow egg development below those rates occurring at ambient temperatures having the same mean values. Time–temperature relations based on the unmodified thermal sums hypothesis and its associated "degree-days" are compared with predicted values obtained using the log-inverse Bělehrádek model as a standard. The former model tends to underestimate the length of the incubation period by an average of about 5 days at incubation temperatures above 4 °C; below 4 °C the former model increasingly overestimates the incubation period. Based on the log-inverse Bělehrádek model, a table is provided of predicted daily rates of development in relation to temperature. The table may be used to predict hatching time in a manner similar to that employing degree-days. In general, the enquiry points to a lack of data on development time at temperatures below 5 °C; to be meaningful, further analyses will require such data. Key words: prediction, modeling, development rates, hatching time
Effects of Cage Culture on Growth, Abundance, and Survival of Resident Largemouth Bass (Micropterus salmoides)
Authors: Kilambi Raj V. , Adams James C. , Wickizer William A.
Published: April 2011

Growth, population size, and survival of resident largemouth bass (Micropterus salmoides) were estimated before, during, and after the cage culture of Salmo gairdneri and Ictalurus punctatus. Growth in length, length–weight relationship, and condition factor were similar among the periods; however, abundance and survival of largemouth bass increased through the 3 yr of investigation. Stomach content analyses showed that the bass fed on fishes (mostly Lepomis macrochirus), crayfish, insects, and zooplankton (predominantly entomostracans). Increase in the standing crops of L. macrochirus and entomostracans during the study periods have provided forage to the increased bass population and thus resulted in greater survival of the young and adult bass of the cage culture and postcage culture periods. Key words: largemouth bass, Micropterus salmoides, cage culture, growth, abundance, survival
Deleterious Effects of Cyanide on Early Life Stages of Atlantic Salmon (Salmo salar)
Authors: Leduc Gérard
Published: April 2011

Hydrocyanic acid, a common industrial pollutant, caused severe damage to developing embryos of Atlantic salmon (Salmo salar) when newly fertilized eggs were continually exposed to sublethal concentrations of the poison (0.01–0.10 mg/L HCN) up to the end of the sac-fry stage. Each test group was held in small flow-through basins with the toxicant metered through the entire experimental period. At 0.08 and 0.10 mg/L, cyanide delayed hatching by 6–9 days but all concentrations reduced hatching success by about 15–40%. During incubation conversion of yolk into body tissues was reduced at all concentrations above 0.01 mg/L. The most striking effect of cyanide, however, was a high incidence of abnormalities ranging from about 6% at 0.01 mg/L to about 19% at 0.10 mg/L. During incubation cyanide had reduced development, but after hatching survival was not affected and growth of cyanide-exposed sac fry was either equal to or faster than that of the controls as a result of higher yolk conversion efficiency. The total metabolism of the sac fry was estimated to explain this phenomenon. To protect salmon streams during embryo–larval stages, the maximum acceptable toxicant concentration for cyanide should not exceed 0.005 mg/L HCN. Key words: cyanide pollution, eggs and fry, embryogenesis, teratogenic effects, Atlantic salmon
Phosphorus Input and Its Consequences for Phytoplankton Standing Crop and Production in the Experimental Lakes Area and in Similar Lakes
Authors: Schindler D. W. , Fee E. J. , Ruszczynski T.
Published: April 2011

Correlation and regression analyses were used to assess several expressions for phosphorus loading, with and without corrections for water renewal and sedimentation, as predictors of total phosphorus concentration, chlorophyll, phytoplankton volume, and phytoplankton production in the Experimental Lakes Area (ELA) lakes. All expressions tested were good predictors, allowing predictions of the above parameters with 95% confidence intervals of 20–30% of the mean for any loading value. In general, correction for water renewal improved the fit of the expression, but correction for sedimentation did not. When the above strategy was applied to lakes outside ELA but with Shield or Shield-like drainage, good results were also obtained when expressions incorporating water renewal were used. If uncorrected for water renewal, loading was a poor predictor. Correction for sedimentation did not improve the expressions significantly. Correction for rapid changes in phosphorus input did not improve the predictability of equations, indicating that the equilibrium between ELA lakes and new loading conditions occurs very rapidly. Key words: Precambrian Shield lakes, eutrophication, lake management, nutrient inputs
A Mathematical Programming Model for the Management of a Renewable Resource System: The Kemano II Development Project
Authors: Everitt Robert R. , Sonntag Nicholas C. , Puterman Martin L. , Whalen Patrick
Published: April 2011

This paper considers a mathematical programming model for the management of a salmon fishery and watershed. Management objectives are specified as bounds and desirable target levels for certain important variables. The mathematical program consists of minimizing the deviation from these targets subject to natural and policy constraints. A detailed application studying the effect of the proposed Kemano II development project on the salmon fisheries of northwestern British Columbia is presented. Parametric programming is used to compare several development scenarios on the basis of the sensitivity of the system to reduce runoff in a specified year. Key words: mathematical models, fishery management, Pacific salmon, sensitivity analysis, experimentation, policy planning
Sorption of Arsenic and Cadmium and Their Effects on Growth, Micronutrient Utilization, and Photosynthetic Pigment Composition of Asterionella formosa
Authors: Conway H. L.
Published: April 2011

By use of continuous-culture techniques, populations of the freshwater diatom Asterionella formosa were exposed to various concentrations of arsenic or cadmium for periods of 6–23 days. Sorption of arsenic (as arsenate) was a linear function of ambient concentrations < 130 μg As∙L−1 but reached an apparent plateau at ambient values > 130 μg As∙L−1. In contrast, cadmium sorption was a complex function of ambient concentration and time. Cellular arsenic and cadmium was desorbed in some of the experiments, and there appeared to be an active regulatory mechanism that kept the cellular arsenic content at a nontoxic level. For arsenic, no detrimental effects on growth or on micronutrient utilization were observed over the range of ambient concentrations used (< 160 μg As∙L−1). For cadmium, however, an ambient concentration of ~2 μg Cd∙L−1 reduced the population growth rate by an order of magnitude, while populations exposed to > 10 μg Cd∙L−1 ceased growth and micronutrient utilization in 20–30 h. Fractionation experiments suggest that a large proportion of the cellular arsenic was associated with the organic layer surrounding the frustule, while most of the cellular cadmium was associated with the cell contents. Key words: arsenic, cadmium, toxicity, sorption, diatom, Asterionella formosa
Applicability of Phosphorus Budget Models to Small Precambrian Lakes, Algonquin Park, Ontario
Authors: Scheider W. A.
Published: April 2011

Phosphorus and hydrological budgets were constructed for four small lakes with Precambrian drainage in Algonquin Park, Ontario. Lake outflow discharge ranged from 21.7 × 105 to 177 × 105 m3∙yr−1. Annual phosphorus input to the lakes from terrestrial drainage and precipitation totaled 36.3–188 kg∙yr−1. The lakes retained 16–41% of the annual input. These data were used to test a series of models that predict the spring total phosphorus concentration in lake water and the mean summer chlorophyll a. The predicted spring phosphorus concentration agreed well with measured values (within 1.3 mg∙m−3) except where human-associated phosphorus input may have contributed to the phosphorus budget of the lake. Agreement between predicted and measured chlorophyll a was not as close. A figure of 0.48 kg P∙capita−1∙yr−1 was calculated as the human-associated supply. Key words: phosphorus budget, chlorophyll a, predictive model, Precambrian lake
Comparison of Two Methods Used by Divers for Sampling Benthic Invertebrates in Deep Rivers
Authors: Rabeni Charles F. , Gibbs K. Elizabeth
Published: April 2011

A modified Hess sampler was developed to estimate standing crop and was compared with rock-filled basket samplers. The baskets, although biased for some invertebrates, consistently collected more individuals and taxa. Both methods showed high efficiency, as measured by the coefficient of variation, which generally decreased with increasing pollution. The relative proportions of each invertebrate group collected by each method were similar in many instances and each method was shown to be appropriate in deep-water situations, depending upon the goal of the study. Key words: invertebrate, sampling, river, artificial substrates, divers
SESSION II. Summary and Overview: Physiological Stresses and Response in Chronically Oiled Organisms
Authors: Anderson J. W. , Malins D. C.
Published: April 2011

not available
Diel Food Selection by Two Sizes of Rainbow Trout (Salmo gairdneri) in an Experimental Stream
Authors: Bisson Peter A.
Published: April 2011

The food selected by small (~ 3 g) and large (~ 45 g) hatchery rainbow trout (Salmo gairdneri), studied over a 28-h period, showed that the fish fed selectively, but often on different prey organisms. Feeding activity was highest during daylight hours but was only loosely associated with increases in invertebrate drift density. The majority of large trout exploited adult chironomids on the surface, whereas small trout fed primarily on midwater drift. At night when drift densities were low the limited feeding that took place apparently shifted to bottom foraging. Prey size was the most important factor affecting vulnerability to predation at all hours. Both large and small fish rarely consumed invertebrates < 2 mm long. Selection of larger individuals among certain prey taxa occurred, and in two important groups (Trichoptera and Chironomidae) large trout ate significantly larger prey than did small trout. By being size selective, the trout lost the opportunity to exploit smaller organisms, particularly Collembola, which constituted the bulk of the total drift. Key words: diel habits, drift, predation, rainbow trout, size selection
Histopathological and Physiological Responses of Fundulus heteroclitus to Naphthalene Exposure
Authors: DiMichele Leonard , Taylor Malcolm H.
Published: April 2011

Mummichogs, Fundulus heteroclitus, were exposed to naphthalene concentrations ranging from 30 to 0.002 mg/L over time periods ranging from 1 to 15 d. Histopathology of exposed animals was evaluated. Major effects were found in the brain, liver, and pancreas down to 0.2 mg/L for a 15-d exposure. The results of these experiments indicate that the toxicity of naphthalene in this fish is due primarily to its effect on blood components. There was also evidence of neurosensory damage at exposures as low as 0.02 mg/L for 15 d. In addition, serum glucose, protein, and cortisol were measured in animals exposed to low levels of naphthalene for 15 d. All were significantly elevated, indicating metabolic stress at exposures as low as 0.02 mg/L. 14C-naphthalene uptake was measured at two concentrations of naphthalene. Naphthalene was found to accumulate in significant amounts in organs most susceptible to pathology. The distribution of naphthalene was found to be independent of its water concentration in all organs tested except the spleen. Key words: toxicity, naphthalene, teleosts, histopathology, uptake, Fundulus, mummichog
Stress Response of Coho Salmon (Oncorhynchus kisutch) Elicited by Cadmium and Copper and Potential Use of Cortisol as an Indicator of Stress
Authors: Schreck Carl B. , Lorz Harold W.
Published: April 2011

Exposure of juvenile coho salmon (Oncorhynchus kisutch) to copper (Cu) produced a marked, dose-dependent serum cortisol elevation. Treatment with cadmium (Cd) did not elicit a cortisol elevation, even in moribund fish. Stressing salmon with sublethal levels of Cu or handling plus close confinement resulted in "ideal" compensation (return to prestress levels) in cortisol titers. Salmon exposed to Cu had depressed serum chloride levels and reduced survival when challenged with salt water. Exposure to Cd did not influence serum chloride or the ability to tolerate salt water. Handling and close confinement produced the same cortisol elevation in controls as in Cu- or Cd-treated fish, but exposure to Cu reduced the ability of the fish to survive the stress of handling and confinement. Cortisol level and other characteristics of the General Adaptation Syndrome of stress should not be universally applied as indicators of stress in salmon. Key words: stress, cortisol, heavy metals, coho salmon, Oncorhynchus kisutch, saltwater adaptation, stress resistance, stress indicator, cadmium, copper
Life History and Abundance of Mysis relicta in Lake Michigan
Authors: Morgan Mark D. , Beeton Alfred M.
Published: April 2011

Mysis relicta was sampled in Lake Michigan approximately monthly with an epibenthic sled, August 1975–July 1976. Total numbers ranged from a low of 23 m−2 in February to a high of 337 m−2 in May and averaged 188 m−2. It was possible to partition the population into five instars. Major peaks in proportions of first instar individuals occurred in March, July, and November. It took about 1 yr for first instar individuals to reach the fourth instar. Growth averaged a little less than 1 mm/mo. Males and females reached maturity and bred in the fourth instar, so females produced their first brood at 1 yr of age. Males died at this time, but females were found to molt to the fifth instar, mate, and produce a second brood approximately 4 mo later. Key words: Mysis relicta, Lake Michigan, life history, abundance
Myxosoma cerebralis: Detection of Circulating Antibodies in Infected Rainbow Trout (Salmo gairdneri)
Authors: Griffin Billy R. , Davis Eric M.
Published: April 2011

Circulating antibody against spores of Myxosoma cerebralis has been detected for the first time in rainbow trout (Salmo gairdneri) affected with whirling disease. An indirect fluorescent antibody test (IFAT) was employed for detection of trout immunoglobulin. Most sera of fish from an infected experimental group were found to give a positive reaction in the IFAT, while the majority of specific-pathogen-free control sera gave no reaction. Reagent preparation as well as staining and evaluation procedures are given. These results provide additional information for understanding the host/parasite relationship and offer a potential for development of a nondestructive serological test for whirling disease. Key words: indirect fluorescent antibody test, immune response, whirling disease
Generation Lengths of Some Temperate Marine Copepods: Estimation, Prediction, and Implications
Authors: McLaren I. A.
Published: April 2011

Only copepodids should be used to trace synchronous cohorts from relative abundance of stages, and only long-lived adults correctly signal new generations from size changes. From extensive published data from Loch Striven, Scotland, life cycles are thus detailed for Pseudocalanus minutus, Microcalanus pygmaeus, Calanus finmarchicus, Centropages hamatus, Temora longicomis, Acartia clausi, and Oithona similis. Generation lengths are also estimated for all but M. pygmaeus from temperatures in nature and from laboratory data on food-satiated development. For stage durations (D) at various temperatures (T), Bělehrádek's temperature function D = a(T − α)−b is used. Temperature response can be about the same throughout a species range. With b fixed, α within a species can be the same for older stages as for embryonic duration, which can thus be used to estimate a for generation length even from a laboratory example at a single temperature. If food-satiated durations are available only for some stages, it can be assumed that other stages are similar (isochronal development). Food-satiated generation lengths predicted thus from the laboratory match those inferred from the Loch Striven samples. Trophic studies may be less revealing than further work on the "intrinsic" determinants of copepod performance. Competition for food should not be assumed in studies of niches and community dynamics of marine copepods. Key words: Copepoda, generation lengths, cohorts, body sizes, prediction, temperature, production, life cycles
Stomach Flushing: Effectiveness and Influence on Survival and Condition of Juvenile Salmonids
Authors: Meehan William R. , Miller Richard A.
Published: April 2011

Hydraulic stomach flushing was an effective method to analyze relative food consumption and feeding habits of young salmonids. Coho salmon (Oncorhynchus kisutch) stomachs were most effectively flushed — 99% of invertebrate organisms (96% of weight of stomach contents); 92% of organisms (83% of weight) were flushed from cutthroat trout (Salmo clarki) stomachs, 90% of organisms (77% of weight) were flushed from rainbow trout (S. gairdneri) stomachs. Stomach flushing did not affect survival of juvenile coho salmon. A significant difference in change in mean condition factor between wild and hatchery fish was found after 30 d (greater change in wild fish), and a significant change was observed between the mean condition factors of control and treated hatchery fish. No difference was found between control and treated wild fish. Key words: stomach flushing, juvenile salmonids, survival, condition, food habits