bluuebunny/crossref_metadata_2025 huggingface dataset:
Mercury Concentration of White Muscle in Relation to Age, Growth, and Condition in Four Species of Fishes from Clay Lake, Ontario
Authors: Scott D. P.
Published: April 2011

Studies of large (about 125) samples of walleye (Stizostedion vitreum), northern pike (Esox lucius), white sucker (Catostomus commersoni), and lake whitefish (Coregonus clupeaformis) from each of four areas of Clay Lake, Ontario, a highly mercury-contaminated lake, have confirmed previous findings that the larger the fish, the greater the white muscle mercury concentration, within species, within populations. This relationship was statistically broken into separate age:concentration and growth:concentration partial regressions; older fish and faster growing fish were generally more contaminated, subject to the above species–area restrictions. However, the generally positive correlation between concentration and condition (as measured by relative heaviness of individuals within area–species samples) found in the previous study is here contradicted; relatively heavier fish tended to have lower Hg concentrations. Despite the relatively small size of the lake (about 11 × 2 km) analyses of multiple covariance indicated profound within-species differences between the samples from the four areas. However, there did not appear to be any obvious correlation between these differences and sediment mercury values.The various statistical relationships do not appear to be simple, first-order regressions; rather, there appear to be significant interactions between age and growth, and age and condition, which tend to change the partial slopes with age. The four species were distinctly different in most of their relationships.
Influence of Fenitrothion on Swimming Velocities of Brook Trout (Salvelinus fontinalis)
Authors: Peterson R. H.
Published: April 2011

The critical swimming velocities of brook trout (Salvelinus fontinalis) following exposure to 150, 500, and 1500 μg/liter fenitrothion were 100, 83, and 70%, respectively, of the performance of control fish. This represented 35 and 60% decrease in power output, respectively, for the two higher concentrations.At step-test intervals longer than 15 min, the critical velocity (ca 4.5–5 lengths [L]/s) was reasonably constant. At shorter step-test intervals, the critical velocity increased rapidly to exceed 7 L/s at a step-test interval of 30 s. The cruising speed of control fish was estimated at 4.5 L/s.The influence of fenitrothion exposure on swimming speed is related to previous studies on sublethal effects of fenitrothion and to concentrations in streams resulting from insecticide spraying.
Circulation in Trout Gills: Presence of "Blebs" in Afferent Filamental Vessels
Authors: Fromm Paul O.
Published: April 2011

Casts of the gill vasculature of rainbow trout (Salmo gairdneri) perfused with Microfil were examined visually. The most conspicuous feature seen was enlargements, called blebs, of the afferent filamental vessels that were located in the outermost region of the interfilamental septa. Several lamellae were supplied by profusely branched afferent lamellar vessels, whereas most lamellae were individually connected to the efferent filamental vessel. Vessels contained in the septal area and those that ran parallel to the long axis of the filaments are also described and possible functions of the blebs are discussed.
Composition of Ovarian Fluid and Eggs of the University of Washington Strain of Rainbow Trout (Salmo gairdneri)
Authors: Satia Benedict P. , Donaldson Lauren R. , Smith Lynwood S. , Nightingale John N.
Published: April 2011

The concentrations of major constituents of ovarian fluid were found to be lower than reported values for the same constituents in blood and urine of rainbow trout (Salmo gairdneri). Glucose and total bilirubin were significantly correlated (P < 0.05) to hatchability, whereas LDH was negatively correlated (P < 0.05).Rainbow trout egg proteins are highly nutritional and contain a higher proportion of essential amino acids than do eggs or human or cows' milk.
A Comparison of Lipids and Fatty Acids of the Ocean Quahaug, Arctica islandica, from Nova Scotia and New Brunswick
Authors: Ackman R. G. , Epstein S. , Kelleher M.
Published: April 2011

Lots of ocean quahaugs, Arctica islandica, respectively from Nova Scotia and New Brunswick, were compared to see if fatty acid compositions might reflect local food sources and thus explain alleged flavor problems. Lipid contents increased from May to July, but detailed fatty acid comparisons including those from flesh and hepatopancreas, gave similar results except with minor details indicative of active feeding. A holding experiment with New Brunswick quahaugs gave essentially the basic lipid composition but after 10 wk compositional variations in fatty acid were suggestive of the effect of nonfeeding. The close fatty acid resemblence among several samples suggests that the ocean quahaug eventually converts ingested fatty acids to a species-specific composition based on those acids common to other northwestern Atlantic shellfish. Certain details of these fatty acid analyses suggest particulate matter sources for some ingested fatty acids. No correlation between flavor and lipid or fatty acid composition could be obtained because flavor problems were not observed in these samples.
Biochemical, Physiological, and Pathological Changes in Pyridoxine-Deficient Rainbow Trout (Salmo gairdneri)
Authors: Smith Charlie E. , Brin Myron , Halver John E.
Published: April 2011

Rainbow trout (Salmo gairdneri) fed a pyridoxine-deficient diet developed clinical signs of the deficiency after 8 wk of feeding. Erythrocyte and muscle glutamic pyruvic transaminase (GPT) concentrations were significantly depressed in deficient fish, while liver GPT was significantly elevated. Liver GPT was also elevated in starved trout suggesting the increase in enzyme concentrations was secondary to the deficiency. A normocyte, normochromic anemia, which responded favorably to pyridoxine, developed in pyridoxine-deficient trout. Microscopic lesions were found in gastrointestinal tract, kidney, liver, pancreas, and thymus of deficient fish.
Hunger and the Capture of Grayling and Char
Authors: Bryan J. E.
Published: April 2011

Arctic grayling, Thymallus arcticus, and Arctic char, Salvelinus alpinus, were collected by angling and seining in remote areas of northern Yukon Territory. Stomach samples were observed to test the hypothesis that fish caught by angling had eaten less food than those caught by seining. The hypothesis was supported by the data for grayling. The data for char were consistent with the hypothesis, but the results were not statistically significant. There was no difference in the sex ratio of fish caught by the two methods. Angling selected larger char than did seining, but there was no evidence of size selection in grayling.
Toxicity of Copper at Two Temperatures and Three Salinities to the American Lobster (Homarus americanus)
Authors: McLeese D. W.
Published: April 2011

The time to 50% mortality (LT50) for lobsters at a particular lethal concentration of copper is longer at 5 than at 13 C but is not affected by salinities of 20–30‰. The lethal threshold of copper for lobsters at temperatures of 5 and 13 C and at salinities of 20 to 30‰ is close to 56 μg/liter.
Changes in Blood Chemistry of Juvenile Steelhead Trout, Salmo gairdneri, Following Sublethal Exposure to Nitrogen Supersaturation
Authors: Newcomb T. W.
Published: April 2011

Groups of juvenile steelhead trout (Salmo gairdneri) were exposed for 35 days to various (103, 105, 110, and 116%) sublethal nitrogen plus argon saturations. Pooled serum samples were analyzed for Ca, Na, PO4, K, Cl, albumin, total protein, cholesterol, alkaline phosphatase, glucose, urea, uric acid, total bilirubin, lactate dehydrogenase, and serum glutamic oxalacetic transaminase. An increase in serum potassium and phosphate, and a decline in serum albumin, calcium, cholesterol, total protein and alkaline phosphatase were noted in steelhead exposed to 116% nitrogen (N2 + Ar) saturation (total atmospheric gas saturation 110%). No major changes in blood chemistry were observed at nitrogen saturations of 110% or less.
Temperature-Induced Changes in Acute Toxicity of Zinc to Atlantic Salmon (Salmo salar)
Authors: Hodson Peter V. , Sprague John B.
Published: April 2011

Three groups of Atlantic salmon (Salmo salar) parr were acclimated to water temperatures of 3, 11, and 19 C. When exposed at their acclimation temperature to lethal concentrations of zinc, cold-acclimated salmon survived longer than warm-acclimated salmon. However, the threshold lethal concentration (LC50) of zinc was highest for salmon at 19 C, i.e. there was less toxicity at the high temperature. At test temperatures lower than prior acclimation temperatures, survival times in zinc were longer but the threshold LC50 was lower, i.e. fish were less tolerant of zinc. The opposite results were seen at temperatures above prior acclimation temperatures.The threshold LC50 may be predicted by the equation LC50 = 1.9611 − 0.1873 Ta + 0.8699 Te − 0.0414 Te2 + 0.00004 Ta Te3, where Ta = temperature of acclimation and Te = temperature of exposure.In polluted rivers, zinc concentrations may be most damaging to fish populations during the winter months. Measured concentrations of zinc and copper in the Miramichi River, New Brunswick were highest in winter when estimated toxicity of metal was also greatest.
Concentrations of Circulating Progesterone During Early Pregnancy in the Northern Fur Seal, Callorhinus ursinus
Authors: Daniel Jr. Joseph C.
Published: April 2011

The concentration of circulating progesterone in the female of the northern fur seal (Callorhinus ursinus) was found to be low at and for about 31/2 mo after ovulation, but began to increase prior to implantation and continued to rise for at least 1 mo thereafter.
Maturation and Spawning of Atlantic Herring (Clupea harengus harengus) in the Southern Gulf of St. Lawrence
Authors: Messieh S. N.
Published: April 2011

Analysis of maturity stages of herring samples taken from the southern Gulf of St. Lawrence shows two maturation cycles for spring and autumn spawning herring. The spring population has a spawning peak in May and the summer–autumn population extends spawning from July through September. Spawning grounds of spring and autumn herring populations and their nursery areas are mapped.
Environmental and Intrinsic Control of Filtering and Feeding Rates in Arctic Daphnia
Authors: Chisholm S. W. , Stross Raymond G. , Nobbs Paul A.
Published: April 2011

Filtering and feeding rates of Daphnia middendorffiana at Point Barrow, Alaska were measured as a function of temperature, food density, animal length, and time of day.The functional relationship between feeding rate and food density followed the hyperbolic pattern typical for filter feeders. Daphnia middendorffiana was found to have comparatively high filtering capabilities at its temperature optimum (around 11 C), with filtering rate increasing with length according to the equation F =.458L3.17. The exponent of this equation was found to be a function of temperature, and the coefficient a function of food density.A bimodal diel rhythm in feeding rate was found in this species in experiments where the animals were held under constant conditions. Feeding rates were maximum at 1400 and 2400, the time of day when the temperature cycle in the ponds passes through the mean daily temperature, which is optimum for feeding in D. middendorffiana. Thus the timing of the rhythm may serve to maximize the daily food gathering ability of this species.
Movements of Sockeye Salmon (Oncorhynchus nerka) in the Skeena River Estuary as Revealed by Ultrasonic Tracking
Authors: Groot C. , Simpson K. , Todd I. , Murray P. D. , Buxton G. A.
Published: April 2011

Movements of adult sockeye salmon (Oncorhynchus nerka) entering the Skeena River were examined in 1969 and 1970 by ultrasonic tracking methods. Fifteen of 18 sockeye released in the lower river seemed to move passively in and out with flood and ebb streams. Two fish moved upstream independent of tides and one salmon swam against ebb and flood currents. Ground speeds in both years of operation were 1.6 km/h during rising and 2.1 km/h during falling tides, causing the fish to be transported downstream by about 3 km per tidal cycle. Three salmon released outside the river mouth in salt water also seemed to ride the tidal flows passively. Ground speeds during ebb (3.6 km/h) were again greater than during flood (2.0 km/h), indicating a net offshore movement. We conclude that these passive movements are not an artifact but that sockeye salmon normally slow down or pause upon reaching the "home river" and drift for a period in tidal currents in the estuary and river mouth before migrating upstream.
Behavioral Responses to Changes in Hydrostatic Pressure and Light During Larval Development of the Lobster Homarus americanus
Authors: Ennis G. P.
Published: April 2011

Larvae of the lobster Homarus americanus hatched and reared under laboratory conditions in shallow water responded to changes in hydrostatic pressure in a depth-regulatory manner. Responsiveness to instantaneous pressure increments ranging from 1 to 20 psi increased linearly up to 10 psi but varied little at higher pressures. Sensitivity to pressure changes was retained throughout larval life up to and including stage IV (megalopa) but stage III and IV larvae were much less responsive than stage I and II. Stage V (1st juvenile) lobsters were nonresponsive to pressure changes. Larvae were much less responsive (in terms of vertical movements) to changes in light intensity than to changes in pressure, and there were no clear, sustained phototactic or photopathic responses in the vertical plane.In the sea, stage I, II, and III larvae showed limited downward movement when released at the surface and generally upward movement when released below the surface. Newly-molted stage IV larvae generally remained at the surface when released there and swam to the surface when released at the bottom; those 14–15 days after molting also tended to remain at the surface but when released at the bottom they generally remained there and found shelters. Newly-molted stage V juveniles generally remained where they were released, both at the surface and at the bottom, but those 13–15 days after molting when released at the surface generally swam to the bottom and found shelters, and when released at the bottom, remained there.
Spawning of Lake Whitefish, Coregonus clupeaformis, and Round Whiteftsh, Prosopium cylindraceum, in Aishihik Lake and East Aishihik River, Yukon Territory
Authors: Bryan J. E. , Kato D. A.
Published: April 2011

Spawning grounds used by lake (Coregonus clupeaformis) and round whitefish (Prosopium cylindraceum) were discovered in the course of an investigation on effects of hydroelectric development. The spawning period for lake whitefish extended from early November to at least mid-December 1973. Lake whitefish spawned over silt and Potomogeton in water which had little current and was 2.0–2.5 m deep. Spawning of round whitefish was probably completed in November. Round whitefish spawned during the day. Eggs were apparently broadcast over a variety of substrata ranging from silt and Potamogeton to gravel and boulder. Round whitefish eggs were deposited in both fast and slow current at depths ranging from 0.7 to 2.5 m. Although deposited in a range of habitats, round whitefish eggs seemed to be most abundant on gravel in fast current at depths less than 1 m.
Midsummer Crustacean Zooplankton Communities in Acid-Stressed Lakes
Authors: Sprules W. Gary
Published: April 2011

The distribution of limnetic crustacean zooplankton species and species associations in 47 industrially acidified lakes of the La Cloche Mountains, Ontario, are examined. pH, which ranged from 3.8 to 7.0, and to a lesser extent lake area and depth are the major determinants of the structure of these communities. Mesocyclops edax, Cyclops bicuspidatus thomasi, Diaptomus minutus, Holopedium gibberum, Diaphanosoma leuchtenbergianum, and Bosmina sp. were common species which occurred over the entire pH range. Tropocyclops prasinus mexicanus, Epischura lacustris, Diaptomus oregonensis, Leptodora kindtii, Daphnia galeata mendotae, D. retrocurva, D. ambigua, and D. longiremis plus some other rare species making a total of 64% of all species found never or rarely occurred below pH 5.0. Polyphemus pediculus, Daphnia catawba, and D. pulicaria were found primarily in lakes with low pH. An increase in the complexity of the zooplankton communities with increasing pH was evident. Above pH 5.0 the communities contained 9–16 species with three or four dominant species; in lakes with pH 5.0 or less the communities comprised one to seven species with only one or two dominants. Compared with relatively unspoiled lakes of similar morphometry in northwestern Ontario (ELA lakes) the La Cloche lakes have unusually simple zooplankton associations, particularly the very acidic lakes. Recurrent group analysis of the La Cloche and ELA lakes indicated that they were both characterized by a single major recurrent group of six species, five of which were common to the two areas. In the La Cloche lakes the group of six species occurred most frequently in lakes with pH above 5.0 although it maintained its integrity even down to pH 5.0. It is concluded that pH has a great effect on these zooplankton communities, primarily in lakes with pH below 5.0 where many species are completely eliminated and even tolerant species become progressively rarer until in some lakes a single species (D. minutus) remains.
Occurrence of Pink Salmon (Oncorhynchus gorbuscha) in Lake Huron
Authors: Collins John J.
Published: April 2011

Pink salmon (Oncorhynchus gorbuscha), which were introduced into Lake Superior in 1956 and have produced eight natural generations there, have now appeared in Lake Huron. The first pink salmon was taken in Ontario waters of Lake Huron in 1971. Successful spawning was observed in one tributary in 1973, indicating that pink salmon could become established in Lake Huron.
Amino Acid Supplementation of Casein in Diets of Atlantic Salmon (Salmo salar) Fry and of Soybean Meal for Rainbow Trout (Salmo gairdneri) Fingerlings
Authors: Rumsey G. L. , Ketola H. G.
Published: April 2011

Fry of Atlantic salmon (Salmo salar) fed a diet containing isolated fish protein grew significantly faster than those fed a diet containing casein without supplemental amino acids, and had improved feed conversion and lower mortality. Supplementing the casein diet with essential amino acids to the levels in the isolated fish protein diet significantly increased growth rate, reduced mortality, and improved feed conversion.When fingerling rainbow trout (S. gairdneri) were fed diets containing soybean meal as the sole source of protein, additions of amino acids to simulate those levels of essential amino acids in trout eggs and isolated fish protein significantly improved growth. Additions of methionine, lysine, histidine, and leucine individually and in several combinations had no effect.
Dynamics of Exploited Whitefish Populations and their Management with Special Reference to the Northwest Territories
Authors: Healey M. C.
Published: April 2011

Available data on mortality, growth, reproduction, and stock size in exploited and unexploited populations of lake whitefish (Coregonus clupeaformis) are reviewed with a view to understanding the dynamics of exploited populations and improving their management. Natural mortality ranged from about 0.20 to 0.80 in unexploited populations. In exploited populations total mortality was as high as 0.94. Unexploited populations showed a wide range of growth rates. Growth rate increased with increasing exploitation, and growth rate in all heavily exploited populations was similar to the most rapid growth rate shown by unexploited stocks. Heavily exploited whitefish matured at a younger age and possibly also at a smaller size than those which were unexploited. Limited data on stock size suggest that although total population size declines under heavy exploitation, the vulnerable population remains of similar size.It is concluded that whitefish respond to fluctuations in population size through compensatory changes in growth rate, the difference between growth rate in a population and maximum growth rate is a measure of its scope for compensating for increased mortality. Populations with slow growth rate and low mortality should, therefore, have the best fishery potential, while those with high growth rate and high mortality have a low fishery potential. Further, it is possible to judge the fishery potential of a population or its stage of exploitation from relatively simple measurements of mortality, growth, age structure, and maturity.
Analysis of Tri-aryl Phosphate Esters and the Determination of Imol S-140 in Fish Tissue and Water Samples by Gas Chromatography
Authors: Murray Derek A. J.
Published: April 2011

This report describes a method for the analysis of tri-aryl phosphate esters used commercially as lubricants. In a fish toxicity study, Imol S-140 (tri-tolyl phosphate) was extracted from fish tissue and water samples, hydrolyzed, and the individual phenols measured by gas chromatography as the trimethylsilyl derivatives. The lower detection limit was about 3 ppm of Imol in wet fish tissue.
Life Histories and Abundance of Crustacean Zooplankton in the Outlet of Lake Superior, 1971–72
Authors: Selgeby James H.
Published: April 2011

In sampling throughout a year, at about 3-wk intervals, of the crustacean zooplankton discharged from Lake Superior through the St. Marys River, 30 species were collected, including three not previously recorded for the lake: the copepod Cyclops strenuus, and the cladocerans Alona costata and Alonella acutirostris. Five copepods, Cyclops bicuspidatus thomasi, Diaptomus ashlandi, D. sicilis, Limnocalanus macrurus, and Senecella calanoides were present in the plankton throughout the year while three other copepods, Diaptomus minutus, Epischura lacustris, and Mesocyclops edax, along with all cladocerans, were present only during summer and fall. Five species of copepods, Diaptomus sicilis, D. minutus, Limnocalanus macrurus, Senecella calanoides, and Epischura lacustris produced a single generation annually; three other copepods and all cladocerans produced two or more generations. All species breed 1–3 mo later in Lake Superior than in lakes Michigan and Erie.
Metabolism of 2′,5-Dichloro-4′-Nitrosalicylanilide (Bayer 73) in Rainbow Trout (Salmo gairdneri)
Authors: Statham Charles N. , Lech John J.
Published: April 2011

Uptake, metabolism, and elimination of 2′,5-dichloro-4′-nitrosalicylanilide (Bayer 73) was studied in rainbow trout (Salmo gairdneri) exposed to 14C Bayer 73 in water. Transfer of trout to fresh water after exposure to Bayer 73 for 12 h resulted in the disappearance of 14C from most tissues after 48–72 h. A 24-h 14C bile to water ratio of 10,000:1 indicated a high degree of biliary concentration. A single polar 14C metabolite was purified from bile. Analysis by analytical thin-layer chromatography, β-glucuronidase hydrolysis, acid hydrolysis, infrared spectroscopy, and mass spectrometry indicated that the material was the glucuronide conjugate of Bayer 73.
Corticosteroid Concentrations in Sockeye Salmon (Oncorhynchus nerka) Exposed to Low Concentrations of Copper
Authors: Donaldson Edward M. , Dye Helen M.
Published: April 2011

Yearling sockeye salmon (Oncorhynchus nerka) were exposed for 1–24 h to 10−7, 10−6, or 10−5 molar cupric sulphate in freshwater aquaria. Plasma cortisol, cortisone, and "total" corticosteroid concentrations were measured by a competitive protein binding technique.Cortisol, cortisone and "total" corticosteroid levels were significantly higher than control concentrations after 1 h of exposure to 10−5 or 10−6 M copper. "Total" corticosteroid and cortisone concentrations were significantly higher than control concentrations after 2 and 4 h of exposure to 10−7 M copper, respectively. Fish exposed to 10−5 M copper died between 8 and 24 h.The data reflect a rapid corticosteroid stress response to lethal and sublethal concentrations of copper. The technique may be of use for rapid evaluation of effluents containing heavy metals, especially those containing a mixture of toxicants.
Incidence of Vibrio parahaemolyticus in Fish, Shellfish, Mud, Water, and Fish Products in the Canadian Maritime Region
Authors: Varga S. , Hirtle W. A.
Published: April 2011

A total of 853 samples taken in the Canadian Maritime Region during 1973 were examined for Vibrio parahaemolyticus. The incidence of organisms was only 1.41% in the samples examined. The organism was isolated during the summer and fall. Isolations were confined to samples taken in areas at the proximity of the shores.
Acute Toxicity of Kanamycin to Steelhead Trout (Salmo gairdneri)
Authors: McBride J. , Strasdine G. , Fagerlund U. H. M.
Published: April 2011

Kanamycin administration at the recommended dosage for the treatment of fish infected with species of Aeromonas and Pseudomonas was found to be highly toxic to steelhead trout. Descriptions of pathological alterations, both gross and microscopic, as well as plasma cortisol concentrations are provided.
Diets of Juvenile Atlantic Menhaden (Brevoortia tyrannus) in Three Estuarine Habitats as Determined from Fatty Acid Composition of Gut Contents
Authors: Jeffries H. Perry
Published: April 2011

Juvenile Atlantic menhaden (Brevoortia tyrannus) feed on zooplankton and particulate organic matter, but the importance of each material in the diet cannot be visually determined, because food is ground to an amorphous paste in the fish’s gizzard-like stomach. During early digestion in the anterior alimentary canal, fatty acids do not appear to change significantly, at least with respect to relative concentrations of saturated and unsaturated groups. Because zooplankton and particulate organic matter have markedly different fatty acid compositions, a hypothetical mixture of the two components can be calculated that best accounts for the observed fatty acid distributions of gut contents. Decreasing reliance on zooplankton, from bay through river to marsh, probably reflects resource abundances in three habitats and demonstrates adaptability of juvenile menhaden to different food supplies.
Movements and Growth of Arctic Grayling (Thymallus arcticus) and Juvenile Arctic Char (Salvelinus alpinus) in a Small Arctic Stream, Alaska
Authors: Craig P. C. , Poulin V. A.
Published: April 2011

Fish movements were monitored in a small arctic stream that drains into the Kavik River near Prudhoe Bay, Alaska. The stream, which flows only during summer, served as a spawning and nursery area for Arctic grayling (Thymallus arcticus). Adult grayling entered the stream shortly after breakup and left again after spawning. Juvenile grayling also entered soon after breakup and many remained throughout the summer. Grayling fry emerged from the gravel in late June or early July and remained until freeze-up (mid-September). Small numbers of Arctic char (Salvelinus alpinus) juveniles also entered the stream to feed.The growth rate of grayling in the study stream was among the fastest recorded for arctic populations. Otolith-based age determinations were preferred as scales tended to underestimate the ages of old fish. Maximum observed age was 16 and age at sexual maturity ranged from 5 to 8.
Simple and Rapid Technique for Repeated Blood Sampling in Rainbow Trout (Salmo gairdneri)
Authors: Lied E. , Gjerde J. , Braekkan O. R.
Published: April 2011

A method for repeated blood sampling from small as well as large fish by puncturing the duct of Cuvier is described. The method is simple and makes possible rapid sampling of relatively large volumes of blood. The method is thought to be less stressing for the fish than earlier methods described. Application of the technique to 20- and 300-g trout resulted in no deaths or apparent damage during a 1-mo observation period.
The Narwhal, Monodon monoceros, in Eastern Canadian Waters
Authors: Mansfield A. W. , Smith T. G. , Beck B.
Published: April 2011

In the Pond Inlet area of Baffin Island in 1963–65, 62 narwhals (Monodon monoceros) were caught in nets and examined. Growth layers occur in both the extruded tusk and in the embedded tooth. The few identifiable food remains in stomachs were of squid and Arctic cod. At birth, the calf measures about 160 cm in length and weighs just over 80 kg. Fully grown females attain a length of 400 cm and a weight of 900 kg. Males reach 470 cm and a weight of 1600 kg. Calving is assumed to occur about once in 3 yr. A conservative estimate for the narwhal population of Canada and northwestern Greenland is approximately 10,000. Although the birth rate is unknown, it is assumed to be similar to that calculated for the closely related white whale; that is, about 9%. The maximum potential annual catch, based on the highest reported Canadian catch of 442 narwhals in 1957, combined with the Greenland catch of 135 and an assumed sinking loss of 50%, is about 1154. This is above the estimated annual production of 900.
Summer Distribution of the Nearshore Fish Community near a Thermal Generating Station as Determined by Acoustic Census
Authors: Kelso John R. M. , Minns C. K.
Published: April 2011

The relation between thermal plumes and fish abundance and distribution was studied at the Pickering Nuclear Generating Station, Lake Ontario, using simultaneous digital echo counting and temperature monitoring systems during summer thermal stratification of the lake.Fish relative abundance varied from 20.8/10,000 m3 to 1,037/10,000 m3 and both these extreme density estimates occurred in the 7.5–12.5-m depth shell. Also, changes in distribution of the nearshore community were apparent during the study period, July–October. The fish community in July was pelagic and selected 10–11 C and 14–16 C. That same community later appeared to become segregated into benthic and pelagic communities. Thermal plumes, either well defined or diffuse, appeared to have little effect on the pelagic community either because fish were not available to elevated temperatures by habitat selection or because fish failed to respond to increased surface temperatures.
Fisheries of the North Pacific.
Authors: Royce William F.
Published: April 2011

not available
Role of Stock Biomass and Temperature in Recruitment of Southern Gulf of St. Lawrence Atlantic Cod, Gadus morhua
Authors: Lett P. F. , Kohler A. C. , Fitzgerald D. N.
Published: April 2011

A multivariate approach was used to elucidate the simultaneous effects of temperature and estimated parent stock biomass on the recruitment mechanism of Gulf of St. Lawrence cod. The second order effects of temperature and estimated stock biomass were key factors in determining egg abundance levels. In addition, egg abundance was closely related to the growth rate of cod. The numbers of larvae increased with the interaction of temperature with egg abundance but decreased with the interaction of egg abundance and time. The most important step in the recruitment mechanism occurs during the juvenile stage, the degree of density dependence being reliant on total biomass of the adult cod stock. A system simulation was constructed amalgamating the equations of early life history of cod with the effects of exploitation on stock biomass. Regular 12-yr oscillations were demonstrated at low levels of catch, while the population became more stable at higher fishing efforts in the absence of environmental effects. The optimal fishing mortality for the Gulf of St. Lawrence cod was found to be F0.4, with a maximum sustainable yield of 42,000 metric tons.
Freedom of Oceanic Research: A study conducted by the Center for Marine Affairs of the Scripps Institution of Oceanography, University of California, San Diego.
Authors: Marr John C.
Published: April 2011

not available
Environmental Salinity: Its Failure to Influence Growth of Atlantic Salmon (Salmo salar) Parr
Authors: Shaw H. M. , Saunders R. L. , Hall H. C.
Published: April 2011

Growth of Atlantic salmon (Salmo salar) parr was studied at environmental salinities of 0.1, 10, and 20‰ in relation to daily rations of 0, 1.0, 1.5, 2.2, and 2.9% of dry body weight. Instantaneous growth rates and food conversion efficiencies for fish in each salinity were similar. Maintenance ration was slightly more in 20‰ than in either the salinity approximately isosmotic with blood (10%) or in fresh water (0.1%).
Nature of Incorporated 14C-Labeled Material Retained by Sulfuric Acid Fixed Bacteria in Pure Cultures and in Natural Aquatic Populations
Authors: Baross John A. , Hanus F. J. , Griffiths Robert P. , Morita Richard Y.
Published: April 2011

The levels of 14C-substrates (glutamic acid, alanine, glucose, and uracil) retained by aquatic bacteria in pure cultures and natural marine and fresh water samples after fixation with 2 N sulfuric acid (H2SO4 to reduce pH to 2) were found to be identical to the amount of 14C-labeled material associated with cold 10% trichloroacetic acid (TCA) precipitates collected on filters. Both TCA and H2SO4 were also equally effective in driving CO2 from solution. In heterotrophic potential studies, therefore, the 14C activity associated with natural bacterial populations collected on membrane filters after H2SO4 fixation represents macromolecules only, and not free substrate pools or low molecular weight metabolites.
Observations on Hatching and Larval Release in the Lobster Homarus americanus
Authors: Ennis G. P.
Published: April 2011

In the American lobster (Homarus americanus) larval release occurs most frequently at night, usually shortly after darkness, but batches of larvae are often released at different times throughout the day as well. The rapid beating of the pleopods by the female, which is necessary for larval release, usually lasts less than 1 min and is sometimes performed without any larvae emerging. The outer egg membranes of those eggs from which larvae will be released at any one time become broken open (hatch) throughout the period following the previous larval release, which means that some prelarvae are ready for liberation for periods up to 24 h prior to being released.
Sublethal Effect of 5-Chlorouracil on Carp (Cyprinus carpio) Larvae
Authors: Eyman L. D. , Gehrs C. W. , Beauchamp J. J.
Published: April 2011

The sublethal effects of 5-chlorouracil, expressed as gross anatomical malformations, on newly hatched carp (Cyprinus carpio) larvae are presented. The percent malformed of those hatched was 1.2 at 0.5 ppm, 2.1 at 1.0 ppm, 2.7 at 5.0 ppm, and 4.3 at 10 ppm. Both a least-squares fit of a hyperbolic model and a linear-regression fit are used to describe the response. The malformations are an incremental effect of exposure to a toxicant which should be considered in addition to egg mortality in assessing the effect of environmental toxicants on populations.
Estimating Survival Rate from Tag Returns: Model Tests and Sample Size Determination
Authors: Youngs W. D. , Robson D. S.
Published: April 2011

This paper brings to the attention of fishery biologists a method of estimating survival and exploitation rates when a series of tag recaptures from angler-killed fish is available; this model is appropriate only for recaptures that are removed from the population. Tests for the appropriateness of the model and methods for determining sample size are presented. The test for the model is imperative since estimates of survival would be meaningless if data do not conform to model.
Daily Pattern of Nitrogen Excretion and Oxygen Consumption of Sockeye Salmon (Oncorhynchus nerka) under Controlled Conditions
Authors: Brett J. R. , Zala C. A.
Published: April 2011

Measurements of the rate of ammonia and urea excretion of fingerling sockeye salmon (Oncorhynchus nerka) in fresh water were made at 2–3-hourly intervals throughout the day (average weight = 29 g; temperature = 15 C). One group of fish was fed a maintenance ration while another group was starved for 22 days. Ammonia excretion rose to a sharp peak of 35 mg N/kg per hour, 4–41/2 h after the start of feeding (at 0830) and fell to a baseline level of 8.2 mg N/kg per hour between 0200 and 0800. Urea excretion remained relatively steady at a mean rate of 2.2 mg N/kg per hour throughout the day, showing no diurnal response to feeding. Starved fish showed a nitrogen excretion rate close to that for both the steady state of urea excretion and the baseline rate of ammonia excretion of the fed fish. Oxygen consumption rose to a peak of 370 mg O2/kg per hour just before and during a 1-h feeding period, decreasing thereafter to a low of 170 mg O2/kg per hour at 0300 h. For the starved fish this diurnal metabolic fluctuation continued from the start in a variable and diminishing form whereas nitrogen excretion showed no such response. The results are discussed in relation to hatchery observations. We conclude that for nonstressed salmon at 15 C ammonia is the chief excretory product of exogenous nitrogen metabolism.
Acute Toxicity of Chlorine to Selected Estuarine Species
Authors: Roberts Jr. Morris H. , Diaz Robert J. , Bender Michael E. , Huggett Robert J.
Published: April 2011

Two flowing water systems designed to test the acute toxicity of chlorine in estuarine water are described, one adapted for microscopic species, the other for larger species. Acute toxicity results for several invertebrate and fish species are presented. Molluscan larvae and Acartia tonsa were the most sensitive species tested, with 48-h TL50 values less than 0.005 ppm.
Acute Toxicity to Juvenile Rainbow Trout (Salmo gairdneri) of Naturally Occurring Insect Juvenile Hormone Analogues
Authors: Leach J. M. , Thakore A. N. , Manville J. F.
Published: April 2011

Median lethal concentrations (LC50) of four insect juvenile hormone analogues (IJHA) for juvenile rainbow trout (Salmo gairdneri) were measured in bioassays with 4-h solution renewal. The most toxic compound tested was Δ4′-dehydrojuvabione, with a 48-h LC50 of 1.4 mg/liter and an estimated 96-h LC50 of approximately 0.8 mg/liter. Juvabione, epimeric mixtures of dihydrojuvabiones, and epimeric mixtures of juvabiols had 96-h LC50’s of 1.5, 1.8, and 2.0 mg/liter, respectively. All fish, including those that survived for 96 h, became lethargic soon after exposure to solutions of the IJHA, and their skins darkened. The toxicants were unstable in aqueous solution.
Isolation and Identification of Blue-Green Algae Producing Muddy Odor Metabolites, Geosmin, and 2-Methylisoborneol, in Saline Lakes in Manitoba
Authors: Tabachek Jo-Anne L. , Yurkowski M.
Published: April 2011

Eleven axenic or unialgal cultures of blue-green algae, 10 producing geosmin (trans-1, 10-dimethyl-trans-9-decalol) and 1 producing 2-methylisoborneol (2-exo-hydroxy-2-methyl-bornane) were isolated from saline lakes in southwestern Manitoba. These compounds are responsible for the muddy flavor in fish and water in some lakes. Algae producing geosmin were Oscillatoria cf. prolifica (Greville) Gomont, O. tenuis Agardh, O. cf. cortiana Meneghini, O. cf. variabilis Rao, O. agardhii Gomont, O. cf. splendida Greville, O. sp., Symploca cf. muscorum (Agardh) Gomont, Lyngbya cf. aestuarii (Mertens) Liebman, and L. sp. Lyngbya cf. cryptovaginata Schkorbatov is the first alga reported to produce 2-methylisoborneol.Actinomycetes, which are known to produce these muddy flavor compounds, were not detected in these lakes.
Lake Erie and its Basin
Authors: Sly P. G.
Published: April 2011

The bathymetry of Lake Erie is separated into Western, Central, and Eastern basins, whose form and feature have been strongly influenced by bedrock geology and the effects of Pleistocene events. The climatic regime is mid-continental but is modified by the overall effect of the Great Lakes, mean annual temperatures have a range of about 21 C. European settlement in the basin began in the early 1800s and land use patterns and historic settlement differ distinctly north and south of the lake. Changes in Lake Erie water quality are strongly associated with both agricultural and industrial development, but did not become severe until towards the end of the 1930s. However, changes and depletion of fish stocks likely owe as much to overfishing as to changes in water quality.
Surficial Sediments of Lake Erie
Authors: Thomas R. L. , Jaquet J.-M. , Kemp A. L. W. , Lewis C. F. M.
Published: April 2011

On the basis of extensive echosounding and grab sampling, three major units have been recognized in Lake Erie: till and bedrock, glaciolacustrine clay, and postglacial muds. These units represent the late glacial and postglacial evolution of the basin and occur in an offshore younging sequence. The main basin of the lake is subdivided by residual glacial moraines into four depositional basins: Western, Sandusky, Central, and Eastern basins. The sediment texture has been defined by moment measures (mean, standard deviation, skewness, and kurtosis), the trends of which are related to the mixing of two primary grain-size populations in the sand- and clay-size ranges. A third grain-size mode in the silt size, composed of fine quartz with some carbonate, has been recognized. This mode has a modifying effect on the symmetry of the two primary populations and may, to some extent, be sufficiently abundant to behave as a discrete population. The trends in the textural characteristics, particularly skewness and kurtosis, have been utilized to define energy regimes at the sediment–water interface which indicates three distinct sedimentary or hydraulic regions: 1) Western basin region — Fine-grained sediment accretion in shallow water related to an imbalance in sediment budget, with high input loadings of fine-grained sediment, and deficit in coarse materials, with an excess of input over sediment export to the Central basin region. This results in net sediment accretion in shallow water with texture in disequilibrium with environmental energy, which produces mixing and suspension, followed by redeposition; 2) Central basin region — West to East coarsening of sediment in textural equilibrium with hydraulic energy, as it relates to increasing fetch under westerly and southwesterly prevailing winds; 3) Eastern basin region — Deepwater basin with sediments showing decreasing size offshore with increasing water depth. The deepwater sediment is modified by the influx of substantial quantities of the silt-size material derived from shoreline erosion in the north shore of the Central basin region.The interrelationships of parameters indicate textural dependence on mineralogic composition, particularly important being the relationship of clay concentration to mean grain size. This has particular value in modelling the physical behavior of clay-associated geochemical elements such as phosphorus.
Forms of Iron and Manganese in Lake Erie Waters
Authors: Burns N. M. , Nriagu J. O.
Published: April 2011

About 95% of the iron observed in the lake water is bound to inorganic particles and is present in the water because of sediment resuspension. Contrary to popular belief, the upwelling of interstitial waters charged with ferrous iron does not appear to play an important part in the regeneration of iron from Lake Erie sediments except when anoxic conditions exist at the sediment–water interface. By contrast, manganese is usually found in the overlying water as a result of the release of interstitial water containing dissolved manganese. This precipitates in oxygenated water so that most of the manganese present in the water is found in the particulate form. However, the released manganese will remain soluble if the oxygen saturation is less than 50%. In general, it was found that both the iron and manganese were in the particulate or soluble form in accordance with the geochemical solubility rules.
Bacterial Distributions in Lake Erie (1967, 1970)
Authors: Rao S. S. , Burnison B. K.
Published: April 2011

Distribution of heterotrophic and coliform bacteria in Lake Erie is a first step in determining the importance of bacteria in the lake. The abundance of these organisms was greatest in the Western basin. Offshore bacterial densities from the Central and Eastern basins were lower than the inshore areas. Detroit River, Grand River (Ontario), and the areas close to Erie, Pennsylvania and Cleveland, Ohio showed the highest bacterial densities throughout the study periods.
Bacterial Flora of Aquarium Fishes and Their Shipping Waters Imported from Southeast Asia
Authors: Shotts Jr. E. B. , Kleckner A. L. , Gratzek J. B. , Blue J. L.
Published: April 2011

Seventy-three plastic containers of aquarium fish and accompanying water from Taiwan, Singapore, Bangkok, and Hong Kong were studied to determine bacterial flora. It was found that 69% of the bags of fish contained individuals with bacteremias. When tissue suspensions of fish were examined 18 genera of bacteria were noted. Fourteen genera were found associated with the shipping water. In each case the two predominating organisms encountered were Pseudomonas sp. (not aeruginosa) and Aeromonas hydrophila complex. Other organisms found included Citrobacter, Proteus, Escherichia, Micrococcus, Mycobacterium, and Flavobacterium. Mycoplasmas were not recovered.
Changes in Blood Chemistry and Blood Cell Morphology in Coho Salmon (Oncorhynchus kisutch) Following Exposure to Sublethal Levels of Total Residual Chlorine in Municipal Wastewater
Authors: Buckley James A. , Whitmore Cecil M. , Matsuda Robert I.
Published: April 2011

Yearling coho salmon (Oncorhynchus kisutch) were exposed for 12 wk to either 0.3, 1.1, or 3.6% chlorinated municipal sewage treatment plant effluent with seawater diluent (average salinity 28‰)under continuous flow conditions. The maximum safe concentration of effluent lies between 0.3 and 1.1% (average total residual chlorine (TRCl2) content 0.003 and 0.009 mg/liter, respectively). Effluent concentrations of 0.3% produced no discernible effects on the fish. Concentrations of 1.1 and 3.6% (average content of TRCl2 0.030 mg/liter) resulted in reductions of hemoglobin and hematocrit to levels indicative of anemia. Observations of the erythrocytes revealed lysed and degenerating cells, increased numbers of circulating immature cells, and abnormal cells. These hematological effects are attributed to the oxidative nature of TRCl2.
Effects of Low Concentrations of Oil Accommodated in Sea Water on the Growth of Unialgal Marine Phytoplankton Cultures
Authors: Prouse Nicholas J. , Gordon Jr. Donald C. , Keizer Paul D.
Published: April 2011

Effects of three oils accommodated in sea water upon the growth of unialgal cultures of marine phytoplankton were investigated. The oil concentrations used covered the range normally encountered in sea water subjected to oil pollution (< 1 mg/liter). In most experiments, minor stimulation or inhibition of growth was apparent but in only two experiments was the growth of oil-contaminated cultures statistically different from controls (in both instances stimulation). Extrapolation of the results to the natural environment is complicated by several factors, the most important of which appear to be variability in organism response and the observation that oil concentration and composition change during experiments. Oil concentrations encountered in polluted sea water can affect the growth of phytoplankton, but the effects seem to be minor and short-lived.
Diel Ecdysis Rhythms in Juvenile Lobsters Homarus americanus
Authors: Tamm George R. , Cobb J. Stanley
Published: April 2011

Juvenile lobsters, held both individually and in pairs, molt primarily during daylight. Eightyfour and 81.4% of the animals molting into the fifth and sixth stages, respectively, did so between 0600 and 1800. The presence of shelter did not significantly affect this pattern, nor did five different holding conditions.