bluuebunny/crossref_metadata_2025 huggingface dataset:
Abundance and Diversity of Mollusca in an Industrialized Portion of the Ottawa River near Ottawa–Hull, Canada
Authors: Mackie G. L. , Qadri S. U.
Published: April 2011

Organic pollution was a major factor in limiting the abundance and diversity of Gastropoda and Pelecypoda in the Ottawa River near Ottawa–Hull. Analyses of 472 Ekman grab samples taken from May to November of 1968 showed that the average standing crops (no./m2) of mollusks were larger in areas immediately upstream than in areas immediately downstream of slaughter house and pulp and paper mill outfalls.
Age and Growth of the Inconnu (Stenodus leucichthys) in Alaska
Authors: Alt Kenneth T.
Published: April 2011

Studies of three anadromous groups (Kuskokwim River, lower Yukon River, Kobuk–Selawik area) and two fluvial groups (upper Yukon River and Minto Flats) of inconnu (Stenodus leucichthys) showed Kuskokwim River fish to be the fastest growing, reaching 81 cm in 10 years. Fish from the slower-growing Kobuk–Selawik samples attained weights over 20 kg and lengths of 110 cm while fish over 12 kg and 100 cm were uncommon from other waters. Females in all groups studied lived longer than males. Age at sexual maturity ranged from 5 to 9 years for males and 7 to 12 years for females.
Parasitism on Juvenile Pacific Salmon (Oncorhynchus) and Pacific Herring (Clupea harengus pallasi) in the Strait of Georgia by the River Lamprey (Lampetra ayresi)
Authors: Roos J. F. , Gilhousen P. , Killick S. R. , Zyblut E. R.
Published: April 2011

River lamprey (Lampetra ayresi) were found to parasitize the young of five species of Pacific salmon (Oncorhynchus) and Pacific herring (Clupea harengus pallasi) in the Strait of Georgia, B.C. The dorsal attachment of the river lamprey is in sharp contrast to the usually ventral attachment of other species of lampreys that parasitize salmonids. Up to 1.9% of young salmon showed evidence of lamprey marks, and marked fish were generally restricted to a narrow size-range. Some of the fish exhibited severe wounds. Evidence from healing wounds on fingerlings and scars on adults indicates that some juvenile salmon survive the attacks of the river lamprey.
Parental Age and Survival of Progeny in Splake Hybrids (Salvelinus fontinalis × S. namaycush)
Authors: Ayles G. B. , Berst A. H.
Published: April 2011

While examining the survival rates of eggs in a splake brood stock, it was found that the survival of progeny from egg to the time of yolksac absorption increased as the age of the parents increased.Examination of spawning success of individual fish in another brood stock indicated that the increased survival rate was related to the female parent. There was no effect of the female parent on survival from eggs to eyed eggs, but there was a significant effect of survival from eyed eggs to hatch and from hatch to the time of yolksac absorption.
Evaluation of a Method for Estimating Food Consumption Rates of Fish
Authors: Carline Robert F. , Hall James D.
Published: April 2011

A method of estimating food consumption rates of fish in nature from laboratory growth data was evaluated using juvenile coho salmon (Oncorhynchus kisutch) in three similar experiments. One group of coho was held individually in aquariums where movement was restricted. Another group was maintained in an experimental stream where the coho displayed many of their typical behavior patterns. All fish were fed known rations and both groups had similar growth efficiencies over a wide range of rations. Coho feeding at intermediate rates had the highest gross efficiencies. Aggressive activity did not affect growth efficiency. Results suggested that laboratory food and growth data may provide reasonably accurate estimates of food consumption of coho salmon in nature.
A Simple Method for Recording Fish Heart and Operculum Beats Without the Use of Implanted Electrodes
Authors: Rommel Jr. S. A.
Published: April 2011

Recording fish heart and operculum beats directly from the water is possible within a limited range of water resistivity. This method can minimize fish handling in some physiological experiments.
A Comparison of Liquid Scintillation and Geiger–Müller Estimates of Primary Productivity in an in situ Experiment
Authors: Ward F. J. , Nakanishi Masami
Published: April 2011

For an in situ experiment conducted in Shiozu Bay, Lake Biwa, Japan, primary productivity estimates from liquid scintillation radioactivity counts of wet algae were generally higher than those from Geiger–Müller radioactivity counts of desiccated algae. Values at 0 m were similar, the G–M estimate at 0.5 m was 10% higher, but from 3 to 13 m the liquid scintillation values ranged from 11 to 33% higher than G–M estimates. The 20-m estimates were low and similar. Differences were caused primarily by 14C losses during desiccation prior to G–M counting. Increasing loss rates between 0.5 and 3.0 m may have been caused by decreasing light intensity. On the basis of surface area, the estimate from liquid scintillation data was 27% greater than that obtained from G–M data.
Age, Growth, Spawning Season, and Fecundity of the Trout-Perch (Percopsis omiscomaycus) in Southeastern Lake Michigan
Authors: House Robert , Wells Larue
Published: April 2011

Growth of trout-perch (Percopsis omiscomaycus) in the first 2 years of life was somewhat slower in southeastern Lake Michigan (average length at end of second year, 83 mm) than in Lower Red Lake, Minnesota (90 mm), but considerably faster than in Lake Superior (58 mm); size differences in later years were slightly less pronounced. Young fish began growing earlier in the year (some before June 20) than older ones (as late as August). Females tended to live longer than males, as they do in Lower Red Lake and Lake Superior.Trout-perch spawned from late June or early July until late September, somewhat later than in Lower Red Lake (May to August) or Lake Erie (June to August). Fecundity was similar to that in Lake Erie; mature females 94–146 mm long contained from 126 to 1329 yolked eggs.
Sampling the Edible Muscle of the Swordfish (Xiphias gladius) for Total Mercury Analysis
Authors: Freeman H. C. , Horne D. A.
Published: April 2011

Total mercury was uniformly distributed in the edible muscle tissue of three swordfish, demonstrating that a small sample of muscle tissue taken from any region is representative of the whole muscle tissue when used for mercury analysis. The mean ± SE total mercury concentrations of longitudinal, depth, and transverse muscle sections from three swordfish were: 1.07 ± 0.04, 1.03 ± 0.04, and 0.99 ± 0.08 μg/g; 0.15 ± 0.01, 0.15 ± 0.03, and 0.14 ± 0.02 μg/g; and 0.55 ± 0.01, 0.61 ± 0.04, and 0.54 ± 0.06 μg/g, respectively.
Beverton-Holt Model of a Commercial Fishery: Optimal Dynamics
Authors: Clark Colin , Edwards Gordon , Friedlaender Michael
Published: April 2011

The problem of optimal regulation of a fishery is discussed. Of special interest is the problem of regulating an overexploited fishery by reducing effort to allow the fish population to build up to a suitable level.We first argue that the problem requires an economic analysis based on the concept of maximization of present value. From this concept we then deduce a simple, general rule, the "Fisher Rule," which we subsequently use to determine optimal exploitation. Among the principal results are the following: (a) an optimal mesh-size is determined, which, because of the discounting of future revenues, is smaller than the size corresponding to maximum sustainable yield; (b) the optimal recovery policy for an overexploited fishery is deduced; it consists of a fishing closure permitting the fish population to reach an optimal age; (c) the optimal development of an unexploited fishery is deduced; an initial development stage characterized by large landings and profits is rapidly transformed into a situation of optimal sustained yield, in which both landings and profits may be significantly reduced; (d) the optimal policy is deduced for a fishery in which gear limitations are impractical; the result may be a strongly unstable fishing industry; (e) the effect of high discount rates, which might be employed by private fishing interests, is discussed; such rates may result in overfishing similar to the case of a common-property fishery.
Influence of Environmental Experience on Response of Yearling Rainbow Trout (Salmo gairdneri) to a Black and White Substrate
Authors: Ritter John A. , MacCrimmon Hugh R.
Published: April 2011

Yearling rainbow trout (Salmo garidneri) selected black substrate regardless of size or rearing experience when first introduced into an experimental tank offering a choice of black or white. Differences in the degree of black selection among the various lots of the same strain during the initial 120 min of exposure, under an illumination of 10−2 lx, were correlated only with the level of swimming activity. By 24 hr, only pond-rearsd fish continued to select black while laboratory-reared fish were randomly distributed over black and white. The continuing wariness of only the pond-reared fish reveals the long-term effect of prior experience on juvenile trout behavior. This finding indicates the possible feasibility of environmental conditioning for wariness in the artificial propagation of hatchery-reared fish for live release.
Influence of Salinity on Protein Requirements of Rainbow Trout (Salmo gairdneri) Fingerlings
Authors: Zeitoun I. H. , Halver J. E. , Ullrey D. E. , Tack P. I.
Published: April 2011

Rainbow trout (Salmo gairdneri) juveniles maintained at 10 and 20 ppt salinity were fed seven diet treatments from 30 to 60% protein in 5% increments for 10 weeks. The fish were stocked in cones, initially 50 fish per cone. Biweekly weights of diets and fish were determined and mortality was recorded daily. Percentage weight gain, gross diet efficiency, and protein efficiency ratio (P.E.R.) were computed. The minimum protein levels required for fish to achieve highest performance using these criteria were 40 and 45% for those maintained at 10 and 20 ppt, respectively. Mortality was significantly (P < 0.05) higher for fish maintained at the higher salinity. Analyses of the fish carcasses were conducted at the beginning and end of the experiment on representative samples to estimate the grams protein retained and apparent net protein utilization (N.P.U.) to verify the above findings. All the available data showed that dietary protein was of major consequence on all measurements until the minimum required level of protein in the diet was reached, while salinity was of minor consequence. P.E.R. and apparent N.P.U. were 2.10 and 34.4, respectively, for casein diets at the 40% protein level.
Food, Feeding, and Condition of Lobsters, Homarus americanus, Throughout the Seasonal Cycle in Bonavista Bay, Newfoundland
Authors: Ennis G. P.
Published: April 2011

The rock crab, Cancer irroratus, and spider crab, Hyas araneus, made up about 50% of the food of lobsters in Bonavista Bay, Nfld. The sea urchin, Strongylocentrotus dröbachiensis, several species of molluscs, and several species of sea stars made up 7.1, 10.9, and 10%, respectively. The remainder was mainly a variety of bottom invertebrates but fish and seaweeds were also fairly common. There was a change to a slightly more calcium-rich diet during the molting season. A rapid increase in feeding activity during the summer coincided with increasing temperatures, but despite decreasing temperatures during the fall, feeding activity remained high. The feeding index for females remained high longer into the winter than for males. Physiological condition was directly related to the molting cycle. Premolt condition was very high, postmolt very low, and recovery to the intermolt condition was attained about [Formula: see text] months after the peak molting period.
Sequence of Exploitation of Stocks in Multispecies Fisheries in the Laurentian Great Lakes
Authors: Regier H. A.
Published: April 2011

The Laurentian Great Lakes have been fished with gradually increasing intensity for about 150 years. Their fish communities have been stressed by a broadening variety of other cultural influences besides fishing. A series of recent analyses have identified and distinguished effects due to fishing from those due to other cultural stresses. These analyses are here carried a step further, showing the fishing-up and overfishing sequence, through time, of various species as a function of their economic value to the fishermen. Some elements of a theory are proposed that interrelate a number of whole-system variables; if elaborated further such a theory should be useful in modelling and managing competing fisheries that harvest a number of ecologically interrelated species, perhaps more or less indiscriminately. Further, the theory should permit modelling and managing of other cultural stresses on the fish community, such as nutrient loading and toxic pollution that may act contemporaneously with fishing.
License Limitation Regulations: Canada’s Experience
Authors: Campbell B. A.
Published: April 2011

In the late sixties, Canada introduced legislation to provide for the limitation of fishing licenses in two specialized fisheries — the lobster fishery of the Atlantic coast, and the salmon fishery of the Pacific coast. These regulations were introduced for economic and not conservation reasons.As a result of the limitation program the number of licensed salmon vessels in British Columbia had been reduced from 7548 in 1968 to 5890 in 1972. The program called for salmon vessels to be grouped into two categories based on their record of production in 1967 or 1968. Vessels with low production ("B" category) can continue in the salmon fishery for only 10 years. License fees for "A" category vessels have been increased sharply. New salmon vessels can only be licensed provided an equal tonnage of "A" category vessels is retired from the commercial fishery. The Government is using the money from licenses to purchase from fishermen active salmon vessels and retire them from the fishing industry. Indians have been given the special privilege, for social reasons, of obtaining salmon licenses for their vessels at minimum cost, but they still cannot license a new vessel unless an equivalent tonnage of vessels has been retired. The average value of individual salmon vessels remaining in the fleet has increased substantially and the higher values are not justified in relation to the increased returns that can be achieved because of the fewer number of fishing vessels. The final phase of the plan is under review by an industry committee charged with making representation to the Government in 1973.In the Maritime Provinces the limitation program for lobster boats has not progressed as quickly as the salmon program in British Columbia. A base, however, has been established: vessels have been divided into "A" and "B" categories but no action had been taken up to September 1972 to limit the life of "B" category lobster vessels. Until this is done, or other means taken to reduce the fleet, very little reduction in the number of boats is expected.These limitation programs, for what are essentially small boat fisheries, are unique, since few attempts have been made in the world’s fishing communities to control the number of vessels for economic reasons. The progress of these programs will provide administrators and economists with criteria for future management.
Fishery Joint Ventures in Developing Countries
Authors: Honda K.
Published: April 2011

To an increasing degree joint ventures are being used to assist developing nations to make better use of the fishery resources in their own waters or adjacent thereof. Japan has been active in this field, providing technical assistance, equipment, training, and fellowships. The Japanese fishing industry has also provided capital and skills.The first Japanese fisheries joint venture was established in 1953 and the system has grown rapidly since; by March 1972 there were 38 countries involved, with 77 enterprises and a capital investment of $25 million. Most joint ventures have been established in Asia and Oceania; Africa has shown the greatest increase in recent years. Most enterprises are for fishing activities, especially trawl fishing for shrimp; the others are for cold storage, fish processing, and aquaculture.About 46% of joint venture enterprises are owned mostly by Japan, but increasingly the local country has an equal or larger share. Most land-based employees are of the local country, but over half the fishermen are Japanese; this reflects the difficulty of obtaining enough skilled local fishermen. One task of the ventures should be to train such men.Successful joint ventures require the following: The national interest of the recipient country should be kept fully in mind; Recipient countries should take the steps necessary for resource conservation, for prevention of conflicts on the fishing grounds, and for avoiding excessive competition; Fisheries require complex infrastructures, including harbors and supply and storage facilities, which cannot be supplied by commercial enterprises. Arrangements should be made by the recipient country to provide these, by the government or through bilateral or multilateral assistance; and Recipient governments should fully appreciate the characteristics and risks of fishery ventures, and take a long view of development. They should recognize the need for exploratory and experimental fishing, and give favorable treatment regarding taxation, employment, import of fishing materials, and remittance of foreign exchange.
Distribution of LDH-B″ Gene in Resident and Anadromous Rainbow Trout (Salmo gairdneri) from Streams in British Columbia
Authors: Huzyk L. , Tsuyuki H.
Published: April 2011

The B″ subunit of lactate dehydrogenase from the liver tissue of wild populations of resident rainbow trout (Salmo gairdneri) from the Loon and Pennask Lake areas has been found in a frequency of 0.400–0.800. An electrophoretically identical subunit was found in similar proportions in anadromous steelhead trout from the Thompson River, and from the Coquihala River in considerably smaller proportions. Steelhead from some coastal streams in and near Vancouver and Vancouver Island, and other selected streams from the Fraser and Skeena river systems generally revealed a very low frequency of less than 0.1.
The Production Biology of the Lower Laurentian Great Lakes — A Preamble
Authors: Vollenweider Richard A.
Published: April 2011

not available
Microbiological Examination of Offshore Lake Erie Sediments
Authors: Dutka B. J. , Bell J. B. , Liu D. L. S.
Published: April 2011

In August 1972 divers collected cores from the Central and Western basins of Lake Erie for microbiological analysis. The cores were sectioned and examined for sulfur cycle bacteria, nitrogen cycle bacteria, total heterotrophs, iron oxidizing bacteria, insoluble organic and inorganic phosphate solubilizing bacteria. Eh, nitrogen, organic carbon, and percentage moisture determinations were also made.Data from these cores indicate that offshore sediments, not directly influenced by land inputs, contain similar, homogenously distributed bacterial populations which vary less than one order of magnitude between the sediment surface and the 5-cm level.
Seasonal Abundance of Crustacean Zooplankton and Net Plankton Biomass of Lakes Huron, Erie, and Ontario
Authors: Watson N. H. F. , Carpenter G. F.
Published: April 2011

Crustacean zooplankton concentrations (numbers per m3) in the upper 50 m found in lakewide cruises during all or most of the seasons on lakes Ontario and Erie in 1970 and on Lake Huron in 1971 showed that the species of zooplankton crustaceans present in the three lakes were generally identical, although the times of maxima and relative species compositions differed. Calanoid copepods were most abundant and diverse in Lake Huron and western Lake Erie. Cyclopoids and cladocerans were most abundant in lakes Erie and Ontario and in the Saginaw Bay region of Lake Huron. The most abundant cyclopoid throughout the year in all three lakes was Diacyclops bicuspidatus thomasi; Tropocyclops prasinus and Acanthocyclops vernalis were abundant especially in lakes Ontario and Erie, respectively. Cladocerans were most numerous in lakes Erie and Ontario. Numbers of individuals fluctuated markedly through the season with maxima in the spring or summer months in all three lakes.Biomass values (ash-free dry weight) were highest in Lake Erie, especially the Western Basin, and in Saginaw Bay of Lake Huron. Although numbers of crustaceans/m3 were much lower in Lake Huron than in Lake Ontario, net biomass values were similar. This was due to the greater size and average weight of crustaceans in Lake Huron samples. Inshore waters of lakes Ontario and Huron and all three basins of Lake Erie were subject to greater fluctuations in concentrations of crustacean zooplankton and net biomass values than in the pelagic waters of lakes Ontario and Huron.
Relation Between Reproductive Potential and Sustained Yield of Fisheries
Authors: Hannesson Rögnvaldur
Published: April 2011

The steady-state yield curve is derived from the growth curve of biomass and shown to bend back toward the origin only if the relative growth rate of biomass is not a monotonically decreasing function of biomass. The bearing of this shape of the yield curve on the possibility of extinction of species is discussed.
Effect of Mincing on Glycolytic Activity in Prerigor Atlantic Cod (Gadus morhua) Muscle Stored in Ice or Frozen
Authors: Nowlan Sandra S. , Dyer W. J.
Published: April 2011

Mincing caused at least a threefold increase in the postmortem rates of both glycogen breakdown and loss of high energy phosphate in unfrozen samples of prerigor Atlantic cod (Gadus morhua) muscle stored at 0 C. During freezing and holding at −3 and −6 C these reactions were accelerated, but the rates in the frozen mince were similar to those in the unminced muscle indicating that mincing has no apparent stimulatory effect on glycolytic activity and dephosphorylation of ATP if the muscle is frozen immediately after it is minced. Thus, minced muscle can be used instead of intact slices in glycolytic studies below 0 C with comparable results so long as freezing takes place immediately after mincing. During large-scale preparation of deboned comminuted muscle from prerigor fish, some glycolysis will occur dependent on the time delay and temperature of holding prior to subsequent freezing.
Lakes — The Vital Water Resource in Canada
Authors: Bruce J. P.
Published: April 2011

not available
Effect of Reinforcement Schedule and Unconditioned Stimulus on Classical Cardiac Conditioning in American Eels (Anguilla rostrata)
Authors: McCleave James D. , Stred Kristin A. , Albert Enoch H.
Published: April 2011

A comparison over 80 training trials of continuous reinforcement with electric shock, reinforcement of every third trial, reinforcement of every fifth trial, and controls without reinforcement, in classically conditioning cardiac deceleration of American eels (Anguilla rostrata) demonstrated the superiority of the continuous reinforcement schedule. However, both intermittent schedules induced some conditioning. Use of a brief "flash of dark" as an alternate unconditioned stimulus to electric shock, was slightly effective in producing conditioned cardiac deceleration. More deceleration occurred in the first interbeat interval following onset of conditioned stimulus (a dim light) than in the second interbeat interval.
First Record of the Margined Madtom (Noturus insignis) from Canada
Authors: Rubec P. J. , Coad B. W.
Published: April 2011

The margined madtom (Noturus insignis) is recorded for the first time in Canada, from a stream tributary to Lac Lapêche, Québec (45°38.5′N, 76°12.2′W). Although its presence could be natural, it was probably introduced by the dumping of bait fish or the introduction of game fish.
Reduction of Atlantic Salmon (Salmo salar) Catches in Canada Attributed to the Greenland Fishery
Authors: Paloheimo J. E. , Elson P. F.
Published: April 2011

Recaptures of Atlantic salmon (Salmo salar) tagged as smolts show that substantial numbers of those produced in the Maritimes are caught in Greenland waters. Percentage recoveries in the home-river system show a significant inverse correlation with levels of catches in Greenland. Analyses of detailed data collected since 1950 indicate that the Greenland fishery has caused serious reduction of Miramichi stocks of 2-sea-winter salmon and will affect the future long-term production of Atlantic salmon in Canada.Total landings have risen higher per million smolts produced in the Miramichi system since the Greenland fishery began. The escapement from fisheries and the potential spawning stock per given numbers of smolts has dropped correspondingly. Lowered escapement has been followed by lowered abundance of progeny as reflected by density of young in nursery stream areas. Significantly, recruitment as measured in numbers of underyearlings depends more crucially on numbers of salmon escaping the fishery than on numbers of grilse. As shown by this statistical analysis, the Greenland fishery has had a direct adverse effect on the numbers of salmon surviving to enter their spawning river. Consequently, the abundant smolt runs in 1964, 1965, and 1968 produced by good escapement some 4 yr earlier failed to maintain adequate levels of recruitment and have instead been followed by all-time low commercial catches and recruitment of young in rivers.
Factors Influencing the Seasonal and Daily Patterns of Alewife (Alosa pseudoharengus) Migration in a Rhode Island River
Authors: Richkus W. A.
Published: April 2011

Continuous time series records of numbers of fish ascending a Denil-type fishway on the Annaquatucket River, North Kingstown, R.I., were obtained with a Smith-Root electronic fish counter during 1971 and 1972 spawning migrations. Seasonal trends in numbers of fish counted per day were unimodal and showed similar time patterns in both years. Water temperatures delimited the seasonal migration period. Short-term fluctuations in fish movement showed a significant zero-lag positive correlation with fluctuations in water temperature and a significant positive correlation with fluctuations in volume outflow when lagged 2 days behind outflow. A 10–14-day cycle appeared in fish migration data. Light intensity determined when alewife (Alosa pseudoharengus) movement would occur during a 24-h period, whereas water temperature controlled the pattern of movement exhibited during daylight hours. Fish responded to hourly water temperatures on the basis of their value relative to a changing baseline temperature.
Bilateral Hyperplasia of the Thymus in a Rainbow Trout (Salmo gairdneri)
Authors: McArdle J. F. , Roberts R. J.
Published: April 2011

Bilateral hyperplasia of the thymus is described in a 3-year-old male rainbow trout (Salmo gairdneri). Two large well-circumscribed lesions were noted in the dorsal gill chamber which consisted of lymphoid and epithelial elements. Structures resembling Hassal's corpuscles were also seen.
Acute Toxicities of a Polychlorinated Biphenyl (PCB) and DDT Alone and in Combination to Early Life Stages of Coho Salmon (Oncorhynchus kisutch)
Authors: Halter Mark T. , Johnson Howard E.
Published: April 2011

Egg hatchability, mean time to hatching, and alevin survival and growth decreased when coho salmon (Oncorhynchus kisutch) eggs and alevins were exposed at 12–14 C to 4.4 μg/liter Aroclor 1254 or higher until 4 wk after hatching, and to 15 μg/liter or more until 2 days before hatching. Premature hatching occurred in all egg groups exposed to the PCB. The median survival times of fry exposed to Aroclor 1254–DDT combinations for two wk were similar to those after exposure to the various concentrations of DDT alone. The more rapid reaction time to DDT is suggested as the basis for lack of additive toxicity.
Atheresthes stomias (Jordan and Gilbert 1880) (Pisces: Pleuronectiformes) and its Eye Parasite Phrixocephalus cincinnatus Wilson 1908 (Copepoda: Lernaeoceridae) in Canadian Pacific Waters
Authors: Kabata Z. , Forrester C. R.
Published: April 2011

Based on the examination of more than 3000 fish, the length and age structure of a population of Atheresthes stomias are described. In offshore waters the modal length for the males was 36–40 cm, that for the females 41–45 cm. In inshore waters smaller fish predominated. The modal age for the males was estimated to be 5 yr, that for the females 7 yr. The shallow water population was younger. With increase in depth of habitat, both age and length of the fish increased, but abundance decreased.Atheresthes stomias feeds on a varied diet, dominated by crustacean species but abounding also in fish, including its own species.Infection with Phrixocephalus cincinnatus diminished with the length and the age of the host, as well as with depth of habitat. The number of fish that appear to have withstood monocular infection with P. cincinnatus was small. Binocular infection seemed to be almost invariably fatal.
Reproductive Potential of Two Lake Whitefish (Coregonus clupeaformis) Populations
Authors: Bidgood B. F.
Published: April 2011

The reproductive potential of two lake whitefish (Coregonus clupeaformis) populations with dissimilar growth rates was studied and compared. The smaller-sized Pigeon Lake females and the larger-sized Buck Lake females had similar ratios of gonad weight to body weight during the gonad development period, but the Pigeon Lake fish produced fewer but larger eggs. Spawning occurred in both lakes for a period approaching 4 mo in both open water and under ice cover in a wide range of water temperatures. Concentrated spawning occurred in shallow water over a boulder, gravel, and sand surficial lake sediment of both lakes. The incubation of whitefish eggs was retarded under ice cover but accelerated to hatching as the water warmed and the ice left the lakes in the spring. The length of the egg incubation period, not the size of the egg under incubation, governed the size of the hatching lake whitefish.
Effect of Temperature on Accumulation of Methylmercuric Chloride and p,p′DDT by Rainbow Trout (Salmo gairdneri)
Authors: Reinert Robert E. , Stone Linda J. , Willford Wayne A.
Published: April 2011

Amounts of mercury and DDT residues accumulated from water by yearling rainbow trout (Salmo gairdneri) in the laboratory increased as water temperature increased. Fish exposed to methylmercuric chloride at concentrations of 234–263 parts per trillion for 12 wk at 5, 10, and 15 C accumulated 1.19, 1.71, and 1.96 ppm; fish exposed to p,p′DDT at concentrations of 133–176 parts per trillion accumulated 3.76, 5.93, and 6.82 ppm. Concentrations of mercury accumulated by the fish were significantly different (P < 0.01) at each of the three temperatures, and the concentrations of DDT were significantly different at 5 and 10 and 5 and 15 C. Throughout the period of exposure, the concentration factors (concentration of contaminant in the fish/concentration in water) at each of the three temperatures were far higher for p,p′DDT than for methylmercuric chloride.
The Mud-Dwelling Hydrozoan Boreohydra simplex in the Western North Atlantic
Authors: Calder Dale R.
Published: April 2011

Boreohydra simplex was collected at a depth of 400 m in Cabot Strait, eastern Canada; this solitary, mud-dwelling hydroid is previously unreported from the western North Atlantic. Elsewhere, it has been found along the coasts of Scandinavia, Britain, and Iceland in the North Atlantic, and from South Georgia in the South Atlantic.
Effectiveness of Vancomycin Against Gaffkemia, the Bacterial Disease of Lobsters (Genus Homarus)
Authors: Stewart James E. , Arie B.
Published: April 2011

The antibiotics vancomycin, penicillin G, novobiocin, and oxytetracycline were examined for in vivo effectiveness against gaffkemia, the fatal bacterial infection of lobsters (genus Homarus) caused by Aerococcus viridans (var.) homari (formerly Gaffkya homari). Only vancomycin was truly effective against an established infection and then only when given at high levels (25 mg/kg lobster body weight) in the early stages of infection, prior to development of hemolymph bacterial numbers in excess of 3 × 104/ml or coincident hepatopancreatic bacterial levels of 1 × 107/g. Even massive cumulative doses (500 mg vancomycin/kg body weight), when given after establishment of maximum bacterial numbers, failed to impede the infection. Rates for the clearance of vancomycin from lobsters, established by using three different concentrations (25, 10, and 5 mg/kg body weight, respectively), were extremely slow and markedly concentration dependent. Twenty-five milligrams vancomycin/kg body weight injected prior to infection still gave a high degree of protection against challenge with the pathogen 50 days later in lobsters held at 15 C. One milligram vancomycin/kg body weight administered prior to infection gave complete protection against gaffkemia for 15 days after the antibiotic had been administered.
A Hermaphroditic Lake Whitefish, Coregonus clupeaformis, from Lake Huron
Authors: Porter T. R. , Corey S.
Published: April 2011

A hermaphroditic lake whitefish, Coregonus clupeaformis, caught in Lake Huron is described. The specimen had a normal growth rate and had no apparent abnormal external characteristics. Both gonads were ovotestes. The ovarian and testicular portions appeared to be functional and developing normally.
Inhibition of Primary Productivity through Heterotrophic Competition for Nitrate in a Stratified Estuary
Authors: Parker R. R. , Sibert J. , Brown T. J.
Published: April 2011

Virtual disappearance of NO3 from Alberni Inlet brackish water containing very sparse phytoplankton with low growth rate was documented using 14C technique with chemical determinations of nutrients and chlorophyll. This phenomenon is explained by the enhancement of the heterotrophic biomass by the organic carbon-rich, nitrogen-deficient, pulpmill effluent and the consequent heterotrophic assimilation of NO3 as a nitrogen source for protein synthesis.
Comparison of Canadian and Japanese Merchant-Ship Observations of Sea-Surface Temperature in the Vicinity of Present Ocean Weather Station "P," 1927–33
Authors: Collins C. A. , Giovando L. F. , Abbott-Smith K. B.
Published: April 2011

A comparison has been made of sea-surface temperatures obtained by Canadian and Japanese merchant vessels in the vicinity of present Ocean Weather Station "P" (50°N, 145°W) from 1927 through 1933. The Canadian data were obtained by thermograph, the presumably more numerous Japanese data by bucket sample. Both data sets clearly display an annual oscillation. Agreement between the sets is good in spite of differences in data density and in methods of observation and of processing. Characteristics (amplitude, phase) of the annual oscillation are more consistent between the sets than is the arithmetic-mean temperature for the period. Heating of water in the condenser intake is suggested as the cause of a slightly greater (0.3 C) mean for the Canadian observations.
Atlantic Salmon (Salmo salar) Taken in the Sea in North Labrador
Authors: Power G. , Cressman Douglas
Published: April 2011

Scale analysis showed that with few exceptions salmon taken near the northern extremity of Labrador were similar to stocks from Ungava rivers; those taken near Nain were probably of local origin. Knowledge of the distribution of local stocks of salmon in the sea contributes to our understanding of their migrations and is valuable in view of the recent development of commercial fisheries for this species in the northwest Atlantic.
DDT Residues in Euphausiids in the Upper Estuary of the Gulf of St. Lawrence
Authors: Sameoto D. D. , Darrow D. C. , Guildford S.
Published: April 2011

No significant variation was found in organochlorine residue levels between different stations in an area from the Saguenay River to the end of the Gaspé Peninsula in the Gulf of St. Lawrence for the euphausiids Thysanöessa raschii, T. inermis, and Meganyctiphanes norvegica. Significant differences were found between the concentration of organochlorine residues for M. norvegica and the Thysanöessa species, but there was no difference between the two Thysanöessa species.Significantly lower values for percent lipid were found in T. inermis and T. raschii between June 1973 and May 1974 samples, but the total amount of organochlorine residues did not change. This suggests that these species do not lose p,p′-DDT when they metabolize lipids for energy or the production of gonad material.
Sea Fisheries Research.
Authors: Edwards R. L.
Published: April 2011

not available
Simplified Spectrophotometric Curcumin Method for the Determination of Boron in Marine Shellfish
Authors: Drew R. E.
Published: April 2011

The method involves a sulphuric acid–hydrogen peroxide digestion of the tissue sample at 100 C, dehydration of the digest with acetic anhydride, formation of the boron–curcumin complex (rosocyanin), followed by buffering of the solution and measurement of the absorbance at 545 nm. Data are presented to show that a mean relative standard deviation of approximately 5% and a mean total error of approximately 12% can be expected for shellfish in the concentration range of 1.0–10.0 μg B/g wet weight tissue (ppm).
Relative Importance of Food and Water in Long-Term Zinc−65 Accumulation by Marine Biota
Authors: Renfro W. C. , Fowler S. W. , Heyraud M. , Rosa J. La
Published: April 2011

Shrimp, crabs, and fish were maintained for 3 mo in a 65Zn-labeled simulated ecosystem in which individuals were allowed to accumulate the radiotracer either directly from the water or from a combined food and water pathway. Shrimp and crabs, receiving 65Zn from the food-water milieu, did not attain significantly higher 65Zn body burdens than those individuals that accumulated the isotope from water only. For fish, the food pathway accounted for only 2.5 times more 65Zn than that obtained after direct accumulation from water. Specific activity measurements of both organisms and water as well as comparisons of radioactive concentration factors with those based on stable element measurements indicated that 65Zn in organisms had not reached isotopic equilibrium with the isotope in the water, even though net 65Zn accumulation in shrimp and crabs had ceased by the end of the experiment. It was concluded that there are zinc pools within adult organisms that exchange only slowly, if at all, with zinc atoms available in the organisms’ food or surrounding water. Hence, aquatic organisms such as those used in this study can most likely achieve true isotopic equilibrium only after living significant portions of their actively growing life stages in a radioactive environment.
Annual and Longer Term Variations of Deepwater Properties in the Coastal Waters of Southern British Columbia
Authors: Pickard G. L.
Published: April 2011

Observations of deepwater properties (temperature, salinity, dissolved oxygen, and the derived values of density) have been assembled from the Data Reports of the Institute of Oceanography of the University of British Columbia and values of the first three properties are presented to show the characteristics of their annual variations at 18 locations in the coastal waters of southern British Columbia. Information on the long-term variations (for 6 yr or more) of all properties is presented for eight of the locations. Variations of 1-yr period are evident to 100 m depth at all locations and to 300 m or more at many of them. The variations are of different forms, sinusoidal, peaked or saw-tooth, and there are some differences in phase between the property variations at different locations. Long-term variations (over several years) of annual mean values are small and decrease with increase of depth. Much of the evidence suggests that the changes below 100 m depth are due to longitudinal advection (flow) from elsewhere rather than to vertical transfers from the sea surface in the immediate locality.
Population and Community Ecology: Principles and Methods.
Authors: Horn Henry S.
Published: April 2011

not available
Sensitivity of Blood Cell Counts in Juvenile Coho Salmon (Oncorhynchus kisutch) to Stressors Including Sublethal Concentrations of Pulpmill Effluent and Zinc
Authors: McLeay D. J.
Published: April 2011

Transfer of fish from optimal to high-temperature, crowded holding conditions decreased white blood cell-thrombocyte (WBC-T) counts markedly on 12–96-h exposure. Red blood cell (RBC) counts were increased only slightly at 12 and 48 h. During 28 days acclimatization following transfer to simulated stream compartments, WBC-T counts returned to stock values within 2–4 days, following an initial decline. RBC counts were not altered appreciably.The decline in WBC-T counts of acclimatized fish to a high sublethal concentration of pulpmill effluent was greatest at 24 h. Mean RBC counts were decreased over 24–96 h, but differences were significant at 24 h only. In acclimatized fish exposed to pulpmill effluent, WBC-T counts were decreased (P < 0.001) at concentrations between 0.2 and 0.9 of the 96-h LC50. A 24-h exposure to 15% vol/vol of this effluent had considerably less effect on the WBC-T count when the effluent had been detoxified by foam fractionation.Under similar experimental conditions, exposure to sublethal levels of zinc depressed mean WBC-T counts proportional to concentration, although differences were only significant at 0.5 LC50 and greater. RBC counts were unchanged.The WBC-T response provides a reasonably rapid and sensitive method for measuring stressful levels of pulpmill effluents to salmon. Declines in WBC-T counts are attributable to reduced numbers of circulating small lymphocytes, which could result in decreased resistance of stressed fishes to disease.
Upper Lethal and Preferred Temperatures of the Slimy Sculpin, Cottus cognatus
Authors: Symons P. E. K. , Metcalfe Janice L. , Harding G. D.
Published: April 2011

The upper lethal and preferred (96-h LT50) temperatures of slimy sculpin (Cottus cognatus) acclimated at 20 C are 25.0 and 13 C, respectively.
A Lakewide Study of Phytoplankton Biomass and its Species Composition in Lake Erie, April–December 1970
Authors: Munawar Mohiuddin , Munawar Iftekhar F.
Published: April 2011

Surface samples of phytoplankton were collected from April to December 1970 at approximately 4-wk intervals from 25 stations distributed over the entire lake. Taxonomic identification and enumeration was done by the Utermöhl technique. About 125–150 species were identified in each basin. "Less common" or rare species contributed significantly to the total phytoplankton biomass. The species comparison among the three basins indicated that species like Rhodomonas minuta and Cryptomonas erosa were perennial in all the basins. Aphanizomenon flos-aquae, Anabaena spiroides var. contracta, Coscinodiscus rothii, Actinastrum hantzschii, and Ceratium hirundinella were typical for the Western basin. Ochromonas spp. and Peridinium aciculiferum were common in the Central basin whereas Gymnodinium helveticum and G. uberrimum were characteristic for the Eastern basin.The diatoms contributed least in the Eastern basin (36%) but showed high percentage in both Central (55%) and Western (58%) basins. The phytoflagellates made important contributions in the three basins; highest percentage (41%) was in the Eastern basin. Phytoflagellate abundance increased from west to east and appeared to have a wide range of adaptability to different nutrient conditions. During July and August high biomass concentration but uneven horizontal distribution was observed. Phytoplankton biomass ranged between 0.8 and 13.2, 0.6 and 6.0, and 1.0 and 4.2 g/m3 in the Western, Central, and Eastern basins, respectively. The highest biomass of 13.2 g/m3 was in the Western basin during April. Inshore–offshore differentiation was observed in the Central and Eastern basins with many peaks in the inshore region. Size analysis of phytoplankton on a few stations showed that the nannoplankton [Formula: see text] comprised a major portion of phytoplankton biomass during spring and fall periods. Based on maximum biomass concentration the Lake Erie Western basin was classified as highly eutrophic, the Eastern basin as mesotrophic, and the Central basin between the mesotrophic and eutrophic conditions.
Seasonal Distribution and Abundance of Crustacean Zooplankton in Lake Erie, 1970
Authors: Watson N. H. F.
Published: April 2011

The lakewide horizontal distribution and seasonal abundance of the cyclopoids, cladocerans, and calanoids in Lake Erie from April to December 1970, are presented.Over much of the year cyclopoids dominated by Diacyclops bicuspidatus thomasi were most numerous with offshore centers of abundance. Several species of cladocerans, often with short peaks of occurrence, were most abundant during summer in the Western basin and associated with south shore population centers in the Central basin. Calanoids were frequently much less abundant than either of the two groups but present in the same areas as the cladocerans.Most species present were short-lived with a high reproductive potential. Environmental clues are postulated to control specific abundance making group numbers more constant. Several life-cycle patterns were evident including species with spring–fall maxima and those with a single peak.Timing of peak abundance of certain species and groups varies from west to east in the same fashion as temperature differences giving rise to east–west gradients of abundance which change with season. Cladoceran and calanoid groups show similarities in distribution pattern with estimates of particulate organic material rather than with algal abundance resulting in north–south gradients of abundance.
Infection of Lumpfish (Cyclopterus lumpus) with Larvae and of Atlantic cod (Gadus morhua) with Adults of the Copepod, Lernaeocera branchialis, in and adjacent to the Newfoundland area, and Inferences Therefrom on Inshore–Offshore Migrations of Cod
Authors: Templeman Wilfred , Hodder V. M. , Fleming A. M.
Published: April 2011

The lumpfish, Cyclopterus lumpus, was found to be a common intermediate host of the larvae of the copepod, Lernaeocera branchialis, in the Newfoundland and neighboring areas. Large numbers of these larvae occurred on the gills of lumpfish from inshore Newfoundland areas from the latter half of June to the first half of August, whereas only minor infection was found in any month in offshore areas. Some larvae of the year reached the final or seventh stage on the intermediate host in May on the west coast of Newfoundland and in June on the east coast. By July on the west coast and early August on the east coast, this was by far the most numerous stage present. The larvae were attached mainly near the tips of the gill filaments. Most larvae were attached to the gills of the first two branchial arches, less to those of the third, and much less to those of the fourth. There were more larvae on the right than on the left gills. Infection of the final host Atlantic cod (Gadus morhua), by stage-7 female L. branchialis was apparently mainly inshore.Adult L. branchialis on Atlantic cod, typically located near the anterior ventral apex of the branchial arches, were numerous throughout the year in the areas of high infection. Infection rates of cod with the adult parasite were usually considerably higher near the coast than farther offshore, the rates declining with distance from the coast. Rates of infection with the adult parasite usually increased from the smaller to intermediate cod lengths and declined rapidly at greater lengths. Infection rates were found useful as evidence of inshore and offshore migrations of cod. Infection with the copepod apparently delayed sexual maturity in cod. Most infected cod (86%) had one adult copepod and declining numbers (12–0.05%) possessed two to five adult copepods. The Greenland cod, G. ogac, was the only other fish of the area found to be highly infected with adult L. branchialis.