bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Technical Development on the Problems and Opportunities in World Fisheries and Their Management
Authors: Eddie G. C. , Insull A. D.
Published: April 2011

In the past quarter-century, fisheries technology has developed to such an extent that the failure of a particular fish stock is not necessarily the unmitigated economic and social disaster it would have been in former times. The development of more flexible, powerful, and controllable systems of production, including marine fish farming, and greater versatility in processing and marketing, mean that the maintenance and improvement of the productivity of the oceans as a whole, in terms of raw protein and oil, are beginning to be of more importance than the conservation of local wild stocks. While failure of a stock may no longer be disastrous, there are other risks, some of them man-made, which may be more serious. Good management must take account of these other risks as well as have regard to the husbanding of the resource.Management must, moreover, be directed to practical objectives of a social, economic, and commercial nature. The degree of attention that should be paid to such matters as capital investment, manpower, training, and education, technical development, and marketing varies according to local circumstances. In many fisheries a lower level of exploitation might be possible if the catch were better utilized, and this would seldom conflict with the objectives of the fishing enterprises concerned. In the past too much attention has been focused on catching operations.Good management must also have due regard to the preservation, processing, and distribution of the catch as well as to the proper use of equipment, manpower, and other resources.It is not easy to devise systems of management that reconcile all the requirements and all the objectives of each of the participating enterprises in a fishery in a practical way. The establishment by a state of jurisdiction over an artificially delimited expanse of ocean, for example, may not necessarily simplify the real problems of management of the fisheries within that area. Greater emphasis on other measures and a partial redeployment of the resources devoted to fisheries protection and fisheries research might lead more quickly than present policies to the establishment of effective methods of exploiting the productivity of the oceans at a higher level.The present assumptions and bases for fisheries management and control throughout the world are questioned, and a new "world approach" is proposed to attain maximum utilization of stocks including productive use of large quantities of "trash fish" and of unfamiliar species.
Chairman’s Summary of the Highlights of the Conference
Authors: Needler A. W. H.
Published: April 2011

not available
Limnology and Education in the Next Decade
Authors: Vallentyne J. R.
Published: April 2011

The prime environmental contingency affecting Canadian limnologists and limnology during the next decade may be a deteriorating economic situation brought about by global demophoric (population × technology) growth. In such an event there would be strong pressure for a fusion of economic and ecological interests, and for organizational arrangements facilitating problem solving. As an adaptation of this fusion, arguments are presented for cooperative education in which students with different disciplinary backgrounds jointly conduct problem-oriented work.
Impact of Recent Economic Growth and Industrial Development on the Ecology of Northwest Miramichi Atlantic Salmon (Salmo salar)
Authors: Elson Paul F.
Published: April 2011

The history of Atlantic salmon (Salmo salar) runs of the Northwest Miramichi from 1950 to 1973 is reviewed. Decreases in these runs are related to degrading of ecological conditions in the river's rearing reaches as a result of adverse chemical conditions attributable to recent developments in forest management and to base metal mining. Diversion of indigenous adult stocks into other streams of the system as a result of pollution of the home stream by mining, pulpmill, and other human activities is examined and evaluated. Increase of commercial catches as a result of pollution-caused delay in the estuary of migrating adults is analyzed. Grave depletion of stocks as a result of the combined effects of these factors plus distant-water fishing is identified, as is incipient recovery of stocks when home-water commercial fishing was eliminated and pollution abatement measures were introduced to the river. A suppressing effect of heavy angling pressure on stock abundance when stocks are low is noted.
Physical and Chemical Limnology of Char Lake, Cornwallis Island (75° N Lat.)
Authors: Schindler D. W. , Welch H. E. , Kalff J. , Brunskill G. J. , Kritsch N.
Published: April 2011

Seasonal data for several physical and chemical variables in Char Lake are given. Annual cycles of major solutes are influenced primarily by freeze–thaw cycles. Concentrations of most substances are increased by freezing–out during the winter. Because the lake does not circulate during maximum spring meltwater flow, this freezing-out maintains concentrations in the lake above those in inflow streams.Concentrations of phosphorus and nitrogen in the lake are low throughout the year. Precipitation contains little phosphorus or nitrogen. Input of phosphorus and nitrogen are calculated to be 0.016 and 0.314 g/m2, respectively. Retention of nutrients by the lake is lower than in temperate regions, although still quite efficient.With the exception of silica, return of ions from the sediments during winter was found to be negligible.Disturbance of one inflow stream due to airstrip construction caused great increases in concentrations of nitrogen, silica, chloride, sulfate, and bicarbonate in the stream.
Benthic Photosynthesis and Respiration in Char Lake
Authors: Welch H. E. , Kalff J.
Published: April 2011

Benthic photosynthesis and respiration was measured by in situ oxygen change and correlated with in situ radiation in ultraoligotrophic Char Lake Oat. 74°42′N). Photosynthesis by the moss and deep sediment zones was correlated with light but photosynthesis by the shallow rocky zone was not. Total benthic gross photosynthesis in Char Lake is 47.5 g O2 m−2 yr−1, or 80% of the total lake photosynthesis. Benthic respiration was 43.6 g O2 m−2 yr−1, in close agreement with the 40.1 g O2 m−2 yr−1 derived from whole lake metabolism. Light input is strongly dependent on snow cover and extinction coefficient. Subsurface irradiance is 24% of the photosynthetically available surface radiation.
Eutrophication in the High Arctic — Meretta Lake, Cornwallis Island (75° N Lat.)
Authors: Schindler D. W. , Kalff J. , Welch H. E. , Brunskill G. J. , Kling H. , Kritsch N.
Published: April 2011

Sewage from the Department of Transport Airport Base at Resolute Bay has caused increases in phytoplankton standing crop, changes in algal species composition, oxygen depletion, and disappearance of Limnocalanus in Meretta Lake. The annual cycles of chemical and physical events associated with these changes are described. Minimum annual input of phosphorus to Meretta Lake was 0.24–0.29 g/m2 of lake surface per year in 1971, with 66–80% supplied by sewage. Nitrogen input was 0.55–0.78 g/m2 during the same year, with 41 to 58% from sewage. Results show that severe eutrophication problems may be expected to develop in response to high nutrient inputs, even at arctic latitudes. Arctic lakes, which are sealed under ice for several months of the year, appear to be particularly vulnerable to increased oxygen depletion which accompanies eutrophication.
A Comparative Review of Phytoplankton and Primary Production in the Laurentian Great Lakes
Authors: Vollenweider R. A. , Munawar M. , Stadelmann P.
Published: April 2011

Species composition of phytoplankton in the Laurentian Great Lakes, its biomass concentration, and its physiological activity measured as photosynthesis related to eutrophication, are reviewed and discussed.
Benthic Macroinvertebrates of the St. Lawrence Great Lakes
Authors: Cook David G. , Johnson Murray G.
Published: April 2011

The history of Great Lakes benthic research from 1870 to the present is briefly reviewed. An examination of the status of taxonomic work on benthic components, and a consideration of the zoogeographical history of the benthos leads to a discussion of bottom communities and macroinvertebrate production in the five major lakes.Profundal communities throughout the lakes are dominated by the glaciomarine relict amphipod Pontoporeia affinis and various species of Oligochaeta, Sphaeriidae, and Chironomidae. The specific composition of these components, and natural and recently imposed changes in their proportions within communities are examined. Population densities and standing stocks, and the proportion of oligochaetes in communities, all tend to increase in response to a natural gradient in productivity inferred from increasing concentrations of parameters such as organic matter and water hardness. Man's influence on water quality anywhere along this gradient compounds the effects of natural factors towards tubificid communities of predictable species composition: Limnodrilus hoffmeisteri, L. claparedeianus, L. cervix, L. maumeensis, Peloscolex multisetosus, and often Tubifex tubifex. The ameliorating influence of water depth is shown in Lake Erie where the change in community composition reflects improving profundal water quality from west to east — a reversed model of the Great Lakes system as a whole.
Zooplankton of the St. Lawrence Great Lakes — Species Composition, Distribution, and Abundance
Authors: Watson N. H. F.
Published: April 2011

Recent studies of zooplankton of the St. Lawrence Great Lakes have concentrated on a broad synoptic coverage of sampling stations and repeated cruises throughout a growing season. This has resulted in a considerable amount of detail about seasonal changes in species composition, total numbers, and vertical and horizontal distributions. Investigators have treated the data to show differences in distribution over the lakes on a cruise and cruise mean averages for each lake, often weighted by area to provide relative abundance figures over the season and between lakes.Maximum numbers were observed in Lake Erie (225,000/m3). Considerably fewer organisms were found in periods of peak abundance in Lake Ontario (55,000/m3) and Lake Huron (22,000/m3). No firm estimates are available for Lake Superior but numbers from one cruise (8000/m3) indicate still lower values there. Biomass estimates (either as ash-free weight of material from planktonnet hauls or from conversions of numbers to biomass from dry weight factors for individual species) are highest for Lake Erie, but reflect the larger size of organisms in the other lakes, especially Huron and Superior.Species distributions are now reasonably well known for crustaceans, except in one or two taxa of the cladocerans Daphnia and Bosmina whose variability should be investigated more fully. Recent studies have been made on the rotifers, but their numbers, distribution, and ecological role is not fully defined. Similarly, the distribution and role of protozoan groups have been largely ignored.Several computer techniques are suggested for the handling and analysis of the large quantities of data generated on lakewide surveys including community coefficients and cluster analyses. More attention should be given to determining sampling intervals to obtain information which can precisely detect changes in abundance from year to year, and better population dynamics and production data are needed to relate zooplankton stocks to eutrophication.
Changes in the Fish Species Composition of the Great Lakes
Authors: Christie W. J.
Published: April 2011

This paper is an interpretive review of the "case histories" which documented the changes in each of the Laurentian Great Lakes for the 1971 symposium on Salmonid Communities in Oligotrophic Lakes (SCOL). It suggests that lakes Huron, Michigan, and Superior passed through a parallel series of stock changes after the invasions of those lakes by the sea lamprey. First, the lake trout and burbot stocks collapsed, and then with the relaxation of predation pressure rainbow smelt, deepwater cisco, and alewife stocks increased. Lake herring stocks collapsed in apparent response to the smelt increase. Whitefish were affected by sea lamprey but recovery after the control of the lamprey in lakes Michigan and Superior suggested that the exotic species had little influence. Lake Ontario differed from the other lakes in that it was inhabited by both sea lamprey and alewife before the turn of the century, and provided the reservoir from which these species expanded to colonize the upper lakes. Alewife apparently equilibrated early, but the evidence was that more recent perturbations allowed the sea lamprey to become a significant factor in the loss of the piscivores of Lake Ontario. Subsequent proliferation of ciscoes and smelt, and collapse of the herring, followed a sequence similar to that of the upper lakes. Lake Erie seemed to be similarly affected by loss of predator stocks, but its predominantly eutrophic character made the situation more complex. Overfishing was indicted in many early stock collapses, in the early invasion of the smelt in lakes Huron and Michigan and in the recent cisco declines of lakes Ontario and Huron. Eutrophication and more direct pollution stresses had mainly inshore impacts, but the similarity in the species sequencing in the oligotrophic Great Lakes suggested that although these factors may have supplemented the other effects, their influence before about 1950 was less than that of overfishing and the invasion of exotic species. Control of sea lamprey, overfishing, and eutrophication seemed attainable in the Great Lakes, but the only defense against further invasions by pest species appeared to be maintenance of sufficiently dense piscivore stocks to assure their suppression. Determining the levels of harvest appropriate to this provision will require intensified research.
Effects of Hydroelectric Development in Western Canada on Aquatic Ecosystems
Authors: Geen Glen H.
Published: April 2011

The effects of some existing and proposed hydroelectric developments on lakes and rivers of Western Canada are considered. There are few pre- and postimpoundment studies from this region on which to base generalizations, although the changes in species composition and water chemistry following impoundment of rivers and lakes reported thus far are comparable to those observed in other areas at similar latitudes. Few data are available which permit prediction of thermal regimes in newly formed reservoirs, particularly in view of the turbid nature of some inflows to reservoirs. Several hydroelectric developments have blocked or impeded migrations of economically important fish and appear likely to produce a number of downstream changes in water temperature or composition, the effects of which are often speculative. More studies of the effects of altered temperature and flow regimes, reduced turbidity, and gas supersaturation are required.
Transferrin Variation in North American Populations of the Atlantic Salmon, Salmo salar
Authors: Payne R. H.
Published: April 2011

A latitudinal cline was indicated by the frequency of the Tf4 transferrin allele in North American populations of the Atlantic salmon (Salmo salar) and an earlier suggestion of a major genetic discontinuity between the salmon populations of Newfoundland and those of the Canadian Maritimes is rejected.Male one-sea-winter fish had a statistically significant deficit of heterozygotes but transferrin phenotypes of one-sea-winter females and two-sea-winter or older fish of either sex agreed closely with the predictions of Hardy–Weinberg–Castle equilibria. Heterozygosity for Tf4 may be semilethal in male salmon programmed to return to spawn after one winter at sea.A comparison of anadromous and nonanadromous salmon populations from the same river system demonstrated that considerable genetic divergence can take place when postglacial crustal recovery produces barriers to upstream migration. The relative fitnesses of the transferrin phenotypes may be different for anadromous and nonanadromous life styles. In view of the demonstrated genetic divergence between anadromous and nonanadromous salmon stocks, the practice of "improving" salmon rivers by removing natural obstructions to upstream migration must be reconsidered in the case of river systems which have large stocks of nonanadromous salmon.
In Vitro Phagocytosis by Hemocytes of the American Lobster (Homarus americanus)
Authors: Paterson W. D. , Stewart James E.
Published: April 2011

A system for holding lobster hemocytes in a viable state was developed and utilized to study the in vitro phagocytosis of sheep red blood cells (SRBC) by lobster hemocytes.Using SRBC sensitized with the opsonin present in lobster serum, 2% of the hemocytes demonstrated phagocytosis detectable as early as 20 min after the hemocytes and erythrocytes were mixed and held at 15 C. Lower phagocytosis levels were observed with untreated erythrocytes. As with other poiklothermic animals, the temperature affected the rate of phagocytosis, which was first observed at the 60-min sampling in cells held at 4 C.
Seasonal Distributions of Bottom Fishes in the Narragansett Bay Area: Seven-Year Variations in the Abundance of Winter Flounder (Pseudopleuronectes americanus)
Authors: Jeffries H. Perry , Johnson William C.
Published: April 2011

Weekly bottom trawl samples taken in Narragansett Bay and Rhode Island Sound from January 1966 through December 1972 showed patterns of occurrence within a diverse assemblage of migratory and resident stocks. Relative abundance of winter flounder (Pseudopleuronectes americanus), the commonest species in the Bay, appeared to be associated with climatic trends but not with fishing pressure. Catch decreased 78% from 1968 to 1972. Average temperature during 30-mo periods, the time required for flounder to reach catchable size, explained 76% of variation in abundance through the study. Annual abundance in the Bay is also reflected 2–3 yr later in the commercial catch. A speculative explanation for control of the population in an estuarine nursery is developed, based on subtle climatic trends whose effects have been magnified many times over by competitive processes among migratory populations.The sand flounder (Scophthalmus aquosus), second in general abundance, varied far less than the winter flounder. Catches of the lobster (Homarus americanus) and winter flounder were directly related, both on a monthly as well as yearly basis. The remaining species of numerical importance appeared to avoid peak abundances of one another in the Bay and Sound; rarely did seasonal maxima of two or more species occur during the same month.
Properties of Age Structure Models for Fish Populations
Authors: Allen Robin L. , Basasibwaki Pereti
Published: April 2011

The behavior of a class of dynamic population models that can be described as a life table operating on a population with a stock recruit relation formed by the product of the egg production and a survival function was examined. A combination of analytical and simulation methods were used to find necessary conditions for the stability of equilibrium populations and the properties of fluctuations about the equilibrium. Regular oscillations that occurred in populations with an unstable equilibrium were of most interest and these were considered as possible causes of the regular fluctuations in populations of fish such as sockeye salmon, Oncorhynchus nerka, or blue pike, Stizostedion vitreum glaucum.
Effects of Water Salinity and Dietary Protein Levels on Total Serum Protein and Hematocrit of Rainbow Trout (Salmo gairdneri) Fingerlings
Authors: Zeitoun Ibrahim H. , Ullrey Duane E. , Tack Peter I.
Published: April 2011

Seven separate diets ranging from 30 to 60% protein in 5% increments were fed for 10 wk to duplicate groups of rainbow trout, Salmo gairdneri, fingerlings maintained at 10 and 20‰ salinity. Water salinity and dietary protein concentration did not significantly influence total serum protein. Hematocrit increased substantially with salinity (35.3% for fish at 10 ppt and 39.1% for those at 20 ppt), whereas different levels of dietary protein were of minor consequence.
Parasites of Freshwater and Anadromous Fishes from Matamek River System, Quebec
Authors: Hanek George , Molnar Kalman
Published: April 2011

In 224 fish of nine species from Matamek River system 38 genera of parasites were recovered (12 Protozoa, 3 Monogenea, 6 Digenea, 6 Cestoda, 6 Nematoda, 2 Acanthocephala, 3 Copepoda). Six genera of parasites were noted in Salmo salar, Salvelinus fontinalis harbored 17 genera, S. alpinus 5 genera, Osmerus mordax 4 genera, Anguilla rostrata 9 genera, Catostomus catostomus 8 genera, Apeltes quadracus 1 genus, Gasterosteus aculeatus 12 genera, and Pungitius pungitius 9 genera.
Adjustment of Buoyancy and Excess Internal Pressure of Swimbladder Gases in Some North American Freshwater Fishes
Authors: Gee John H. , Machniak Kazimierz , Chalanchuk Sandra M.
Published: April 2011

All 12 species of physostomes and 8 species of physoclists altered their buoyancy in response to a change in water velocity. All species showed excess internal pressure of swimbladder gases.
Fluoride Concentrations in Two Pacific Coast Inlets — an Indication of Industrial Contamination
Authors: Harbo R. M. , McComas F. T. , Thompson J. A. J.
Published: April 2011

A comparative study of fluoride levels in Kitimat Arm and Howe Sound, B.C. has been undertaken. Higher average fluoride concentrations, especially for surface waters in Kitimat Arm, indicate that some contamination due to an aluminum smelter has occurred. A statistical treatment of the data further serves to demonstrate this conclusion.
Meristic Variation in the Threespine Stickleback, Gasterosteus aculeatus, in the Matamek River System, Quebec
Authors: Coad Brian W. , Power G.
Published: April 2011

Samples of threespine sticklebacks, Gasterosteus aculeatus, from two lakes and a river in the Matamek River system, Québec were analyzed for five meristic characters. Mean vertebral number differed for each area (range 32.00–32.85) but mean soft fin ray number showed little variation (dorsal rays 11.52–11.79, anal rays 8.68–8.76). Gill raker number was higher in the lake samples (21.25 and 21.80) than in the river sample (20.76). In Matamek Lake only semiarmatus plate morphs were found; in Bill Lake, semiarmatus and trachurus morphs in a ratio of 4:1 with about 10% intermediate; and in the lower Matamek River, semiarmatus and, at a low frequency, leiurus morphs.
Utilization of Blue Whiting, Micromesistius poutassou, for Human Consumption
Authors: Dagbjartsson Björn
Published: April 2011

Blue whiting (Micromesistius poutassou) is similar to other gadoid species in chemical composition. Eating quality is good and close to that of cod and related species. It is also an excellent raw material for pet food, fish feed, and edible fish powders.Production of minced block seems to be a more promising processing method than fillet block and applicable machinery is available for this purpose. Minced blue whiting is darker in appearance than most other whitefish products and is stable for only 3 mo in frozen storage. Bleaching adversely affects the eating quality.Salting and drying of gutted blue whiting as well as air drying of unsalted fish is under investigation.
Density of the Commercial Spider Crab, Chionoecetes opilio, and Calibration of Effective Area Fished Per Trap Using Bottom Photography
Authors: Miller R. J.
Published: April 2011

Bottom photography was found to be a more accurate method of censusing the commercial spider crab, Chionoecetes opilio, than trawling or sight counting from a submersible. Because of their highly aggregated distributions, estimating abundance of mature female crabs and immature crabs of both sexes was not practical by any method. The larger males (≥ 40 mm carapace width), including those of commercial value, approached a random distribution, however; and abundance estimates for four study areas ranged from 5.2 to 9.2 crabs/500 m2 and from 2.2 to 4.2 kg live weight/500 m2. To permit results of exploratory fishing with traps to be converted to crab density and size of crab stocks available to a commercial fishery, a commercial crab trap was calibrated for "effective" area fished. The effective fishing area per trap averaged 4100 m2 over four study areas.
Effect of DDT on Discriminating Ability of Rainbow Trout (Salmo gairdneri)
Authors: McNicholl Patricia G. , Mackay W. C.
Published: April 2011

Rainbow trout (Salmo gairdneri) trained to discriminate between a bright (723 lx) and a dim (22 lx) light were tested to determine the minimum difference in light intensity they could distinguish before and 71 h after being given DDT orally at 0, 30, 50, and 80% of the LD50 dose. Discriminating ability decreased linearly with increased dose, while performance and retention were unaffected.
Mercury in Seals, Terrestrial Carnivores, and Principal Food Items of the Inuit, from Holman, N. W.T.
Authors: Smith Thomas G. , Armstrong F. A. J.
Published: April 2011

Total mercury analyses were made on liver and muscle of ringed and bearded seals, of caribou, and on muscle of Arctic char (the principal items in the diet of local people), of Arctic fox and sledge dogs (which feed mostly on ringed seal) and on wolves (predacious on caribou). About half of the 123 samples were also analyzed for methyl mercury, and some for selenium.Ringed seals showed mean total mercury levels of 27 ppm in liver and 0.73 in muscle. Bearded seals showed 143 in liver and 0.53 in muscle. In the livers, methyl mercury was a small fraction of the total, being 5.6% in ringed and 0.38% in bearded seals. There were positive and significant correlations of mercury content with age and body weight. In Arctic char, mean total mercury was 0.049 ppm, and in caribou 0.20 in liver and 0.017 in muscle. In Arctic fox, values for liver and muscle were 0.77 and 0.32, and in sledge dogs 11.5 and 0.79 ppm.Seals form only part of the diet of the local people. Blood mercury levels have been reported for this community as being above average though not dangerously so. A change in diet, such as increased consumption of seals, might change this.
Tocopherol Composition of Frozen Atlantic Herring (Clupea harengus harengus) Tissues and Oil
Authors: Engelhardt F. R. , Geraci J. R. , Walker B. L.
Published: April 2011

The concentrations of tocopherols in frozen stored Atlantic herring (Clupea harengus harengus) tissues were examined and found to vary with tissue type and the reproductive state of the fish. Only oc-tocopherol was found to be present in herring muscle and oil.
Effects of Saline Water from North Dakota Lakes on Survival of Fathead Minnow (Pimephales promelas) Embryos and Sac Fry
Authors: Burnham B. L. , Peterka J. J.
Published: April 2011

Eggs and sac fry of the fathead minnow (Pimephales promelas) were subjected in the laboratory to various dilutions of water obtained from four saline North Dakota lakes; three were sodium sulfate-, one a sodium chloride-type lake. In water from the latter, the percent of fertilized eggs surviving as sac fry for 5 days remained the same as the percent hatched: about 90% at treatment levels of 500 – 12,000 μmho and 68% in undiluted lake water of 18,000 μmho. In sodium sulfate-type water, however, about 92% of the fertilized eggs hatched at treatment levels of 500 up to only 6,000 μmho, with about 82% living as sac fry for 5 days in water from two of the lakes, and only about 54% living for 5 days in dilutions made from the most saline lake (lake water of 25,000 μmho). No sac fry survived for 5 days after hatching in sodium sulfate-type water of 12,000 μmho. From laboratory bioassays and field observations, we estimated sodium sulfate-type water exceeding 8,000 μmho during reproductive periods may decrease survival of sac fry.
Effects of Kokanee Salmon (Oncorhynchus nerka) Decomposition on the Ecology of a Subalpine Stream
Authors: Richey Jeffrey E. , Perkins Michael A. , Goldman Charles R.
Published: April 2011

The role of kokanee salmon (Oncorhynchus nerka) carcass decomposition in the nutrient cycles and energy flow of a subalpine stream was investigated during a season (1970–71) of high spawner abundance and a season (1972–73) of low spawner abundance with a December storm flushing the stream of carcasses. Primary production, periphyton biomass, heterotrophic activity, and nutrient concentrations were greater downstream than upstream during the peak carcass decomposition of 1971, whereas they were the same at other times of that year and in 1972–73. Calculations showed that upstream–downstream differences in phosphate could be accounted for by the salmon carcasses.
Modem Inshore Fishing Gear — Rigging and Mending.
Authors: Carrothers P. J. G.
Published: April 2011

not available
Biological Parameters of the Antarctic Minke Whale at the Virginal Population Level
Authors: Ohsumi Seiji , Masaki Yasuaki
Published: April 2011

New data from Japanese catches in Antarctic seasons 1971–72 and 1972–73 are used to calculate biological parameters. Determinations are: fetal sex ratio (52.0% females); sex ratio in catch (54.1% females); [Formula: see text], males (27.9 ft), females (29.5 ft); age at asymptotic body length, males (18–20 yr), females (20–22 yr); male sexual maturity at testis weight (0.4 kg); length at beginning of sexual maturity, males (21 ft), females (24 ft) and at 50% sexually mature, males (23.6 ft), females (26.2 ft); age at sexual maturity, females (6 yr); apparent pregnancy rate (89.5%); annual ovulation rate (0.866); litter size (1.007); natural mortality coefficient of sexually mature sample (0.127) and of sexually immature sample (0.213); age at recruitment (6 yr); and rate of recruitment in virgin population (0.119).
New Records of the Pygmy Right Whale (Caperea marginata) from South Africa, with Comments on Distribution, Migration, Appearance, and Behavior
Authors: Ross G. J. B. , Best P. B. , Donnelly B. G.
Published: April 2011

Nine South African records of Caperea marginata are strongly seasonal, all occurring in the period December–February. The world distribution is summarized, based on a total of 71 individuals. Migration may include dispersal of juveniles into inshore waters in spring and summer. The first underwater photographs of this species are presented, and from them and other records, the body shape and external pigmentation are described. Behavior in the wild is unspectacular, probably making the species relatively inconspicuous at sea.
Status and Aspects of the Life History of the Bottlenose Dolphin, Tursiops truncatus, in Florida
Authors: Odell Daniel K.
Published: April 2011

Aerial censuses in waters of the Everglades National Park, Florida every 1–2 mo between September 1973 and August 1974 resulted in sightings of a minimum of five, a maximum of 79, bottlenose dolphins. Seasonal variation in numbers apparently occurs.
Distribution and Differentiation of Populations of Dolphins of the Genus Stenella in the Eastern Tropical Pacific
Authors: Perrin William F.
Published: April 2011

There are at least two races of spotted dolphin, Stenella attenuata, in the eastern Pacific, based on length, color pattern, and skeletal differences. The coastal form is provisionally called S. attenuata graffmani. The offshore form is distinct from a third, Hawaiian race. Likewise, at least three unnamed races of spinner dolphin, S. longirostris, occur in the eastern Pacific. Length, shape of adult male, color pattern, and cranial differences are used to distinguish a Costa Rican, an eastern, and a whitebelly race. An Hawaiian race is distinct from these. A distributional break may indicate two stocks of the striped dolphin, S. coeruleoalba.
Progress Report on the Biology of the Franciscana Dolphin, Pontoporia blainvillei, in Uruguayan Waters
Authors: Brownell Jr. Robert L.
Published: April 2011

Over 400 Franciscana dolphins, Pontoporia blainvillei, were examined throughout the 12-mo fishing season that they are captured in gillnets set for sharks off Uruguay. Female sexual maturity was at 137–146 cm. Near-term fetuses 63–70 cm long were found between September and December. Main prey species in the austral summer were Cynoscion striatus, Porichthys porosissimus and Trichiurus lepturus, and in the austral winter, C. striatus, Trachurus lathami, and Engraulis anchoita. Common internal parasites included nematodes, Contracaecum sp. and at least one other genus, from the main stomach, and an acanthocephalan, Polymorphus cetaceum, found only in the stomachs. Past catches include a minimum of 536 between 1969 and 1973 taken in all months.
Preliminary Report on the Norwegian Fishery for Small Whales: Expansion of Norwegian Whaling to Arctic and Northwest Atlantic Waters, and Norwegian Investigations of the Biology of Small Whales
Authors: Christensen Ivar
Published: April 2011

Whaling for minke whales commenced off Norway in the 1920s. The fishery expanded to the Shetland–Faeroe Islands by 1938–39, to Denmark Strait by 1966, and to Labrador in 1969. Bottlenose whale catches have declined, partly due to economic factors. Modern catches of minke whales are 2000–2500 per annum. Evidence from length-group frequencies and sex composition indicate separate minke stocks in east and west North Atlantic. Segregation by age and sex is documented.
Relation Between Stranding Mortality and Population Abundance of Smaller Cetacea in the Northeast Atlantic Ocean
Authors: Brown S. G.
Published: April 2011

The most complete and continuous series of stranding records is probably that for the British coasts, comprising 1616 strandings between 1913–72. The common or harbour porpoise (Phocoena phocoena) is most numerous (667 strandings, 41% of total), with 17 other species representing the remaining 59%. These data are related to sightings during two transatlantic yacht races, from a bird observatory off southwest Ireland, and from weather ships. The ratio of Irish sightings to strandings is at least 120:1, the ratio of sightings at weather ship stations to strandings of long-finned pilot whales (Globicephala melaena) is at least 150:1.
Long-Finned Pilot Whales, Globicephala melaena, driven ashore in Ireland, 1800–1973
Authors: O’Riordan C. E.
Published: April 2011

Naturally occurring strandings or inshore migrations of pilot whales, Globicephala melaena, have been utilized on an opportunistic basis with yields of from 25 to approximately 300 animals. Single animals strand occasionally. Strandings or captures occur in all months except September. The commonest cetacean in Ireland is the common porpoise (Phocoena phocoena) but there is no fishery for it. It is sometimes entangled in nets. Commercial whaling from 1908 to 1923 took mainly fin whales and other species of large cetaceans. There has been no commercial whaling in Ireland subsequently.
Modified Leslie–DeLury Population Models of the Long-Finned Pilot Whale (Globicephala melaena) and Annual Production of the Short-Finned Squid (Illex illecebrosus) Based upon their Interaction at Newfoundland
Authors: Mercer M. C.
Published: April 2011

Distributions and seasonal movements of Globicephala melaena and Illex illecebrosus evince similar patterns and the cetacean feeds almost exclusively on the cephalopod while inshore at Newfoundland. Peaks in Newfoundland landings of both species are coincident and this is taken to indicate that availability of pilot whales inshore depends on that of short-finned squid. Progressively higher peaks in squid landings with progressively lower peaks in whale landings are interpreted to indicate depletion of the whale populations. Utilizing squid landings as a correction for availability of whales, closed system models are generated to estimate the initial population size of the exploited pilot whales at less than 60,000. Estimates of potential squid consumption by these stocks indicate that annual squid production may be in the order of several hundred thousand tons.
Preliminary Report on the Former Net Fisheries for Tursiops truncatus in the Western North Atlantic
Authors: Mead James G.
Published: April 2011

The net fishery for Tursiops truncatus, the bottlenose dolphin, is relatively well documented at Cape Hatteras, less so at Cape May. The Cape Hatteras fishery peaked in 1885–90, with catches of 2000 and more per annum. Catches were largest during fall and spring months; few porpoises remained, or were caught, in the area in summer. School size was up to 600, with a nearly equal sex composition but a wide size range in spring. Possibly there was more segregation in fall. Fetal lengths reported might indicate two breeding peaks. The present status of the population is not known.
Review of the Live-Capture Fishery for Smaller Cetaceans Taken in Southern California Waters for Public Display, 1966–73
Authors: Walker William A.
Published: April 2011

In a sample of 132 cetaceans taken during 1966–72 in a live-capture fishery for display at Marineland of the Pacific, mortality was low in Tursiops sp. (initially 10%, to over 50% within 24 mo, and high in Delphinus delphis (70% within 1 mo). Mortality within 1 mo and within 24 mo was under 20% and over 60%, respectively, for Lagenorhynchus obliquidens; and under 40% and over 60% for Globicephala macrorhynchus. Small numbers of Lissodelphis borealis and Phocoenoides dalli were also taken.
Live-Capture Killer Whale (Orcinus orca) Fishery, British Columbia and Washington, 1962–73
Authors: Bigg Michael A. , Wolman Allen A.
Published: April 2011

In British Columbia and Washington 263 killer whales (Orcinus orca) were caught during 1962–73 of which 50 were kept for oceanaria, 12 died during capture operations, and the remainder escaped or were released. Peak cropping years were 1967–70 when 77% of all whales removed from the water were taken. Lengths of cropped males were 2.49–6.98 m and females, 2.80–6.25 m. Of 28 females taken an estimated 43% were mature and of 30 males, 20% were adult. The equation relating body length in centimeters and weight in kilograms is W = 0.000208 L2.577. Revenue to netters from the sale of 48 killer whales is estimated to be about $1,000,000. Of 48 whales held in captivity 48% were still alive on April 1, 1974. Survival to the end of 2 yr in captivity is 75% in whales thought to be immature and 13% in adults. The history, capture localities and techniques, and management regulations of the killer whale fishery are also described.
Fish Viruses — Survival and Inactivation of Infectious Pancreatic Necrosis Virus
Authors: MacKelvie R. M. , Desautels Denise
Published: April 2011

The survival of infectious pancreatic necrosis (IPN) virus under conditions pertaining to its retention in the laboratory, and its inactivation by several physical and chemical means were examined.Approximately 99.9% of infectivity was lost when washed IPN virus (106.5–107.0 TCID50/ml), suspended in phosphate buffered saline (PBS) and Eagle’s Minimal Essential Medium diluted 1:10 with PBS, was held at 4 C for 1 yr. After 2 yr more than 102 TCID50/ml remained in both suspensions. The virus survived equally well for 1 yr in 20 and 50% glycerol.Thermal inactivation of IPN virus at 60 C proceeded in a two-component manner, each component following first-order kinetics. At neutral pH, the infectivity of 107 TCID50/ml was reduced by 99.9% in the first 30 min of exposure. After 5 h, 0.0001% still survived. Inactivation rate of the initial rapid component was increased by adjustment of pH to 3 and 10.The curve for the 1:4000 formalin inactivation of 106.5 TCID50/ml of IPN virus was multiphasic. When formalin-treated virus was titrated, cytopathic effect was delayed.Under a UV intensity of 2000 μW/cm2, the infectivity of 107 TCID50/ml of virus was lost exponentially during the first 6 min of exposure after which it abruptly leveled off. The curve was less steep and curvilinear under an intensity of 440 μW/cm2. The level of tailing was the same in both cases.IPN virus was predictably stable at pH 7 at 4 C. A surprising 0.001% of an original concentration of 107 TCID50/ml survived incubation at pH 9 and 2 for 5 wk. The reported survival of IPN virus in homeothermic animals was related to its ability to withstand prolonged exposure to low pH and to its relative heat stability.
Spatial Model for an Exploited Shellfish Population, and its Application to the Georges Bank Scallop Fishery
Authors: Caddy J. F.
Published: April 2011

Existing fisheries models employ the "unit stock" concept that makes no explicit allowance for spatial distribution of biomass and effort over a fishing ground. The utility of the unit stock concept rests largely upon the "dynamic pool" assumption. However, this is both invalid for sedentary species, and difficult to apply when information on spatial distribution by statistical subunits is available, as for the Georges Bank (lat. 42°N, long. 67°W) scallop population. By reference to the Georges Bank scallop fishery, more realistic general assumptions for a spatial model of shellfish populations are:a) Recruitment occurs in patches of random size and location with the constraint that local biomass does not exceed the virgin biomass of each unit area.b) The fraction of effort expended within each statistical area of a fishing ground is either determined by available local biomass alone (proportional effort allocation) or in combination with "traditional fishing practice."Therefore, a spatial model (YRAREA) simulating nonrandom recruitment and harvesting of sedentary organisms is postulated and applied to Georges Bank scallop stocks. Some of the general predictions of this model differ significantly from those employing the unit stock concept, as follows:1) Under proportional effort allocation, overall yield declines more sharply with increasing effort subsequent to maximum sustained yield (MSY) than under dynamic pool assumptions. 2) Peak mortality and the apparent point of full recruitment on the catch curve occur progressively earlier in life (even at partially recruited ages) with increased effort or degree of clumping of the population, and subsequently declines with age, except where "fully recruited" ages coincide spatially with the "target" age-group making up the largest biomass component. This may be of general relevance to fisheries under intensive exploitation with sophisticated methods of navigation and fish finding; peak mortality may occur earlier in life than predicted from the gear selection ogive, if year-classes are independently distributed and there is no size limit regulation. 3) Variance in biomass/unit area is predicted to fall with age.For the Georges Bank scallop population, the model described herein predicts that a substantial increase in yield would result from diversion of effort from the Northern Edge to less heavily fished areas of the bank.
Changes in Abundance and Certain Biological Characteristics of Grand Bank American Plaice, Hippoglossoides platessoides
Authors: Pitt T. K.
Published: April 2011

Commercial exploitation of American plaice on the Grand Bank increased from the early 1950s reaching a peak of about 90,000 tons in the mid-1960s. Catches have subsequently declined to about 45,000–50,000 tons annually. The increased exploitation of plaice was reflected in declines in catch per hour and stock abundance of fully vulnerable age-groups and an increase in the rate of instantaneous fishing mortality (F). The documentation of these was particularly strong in ICNAF Division 3L, but appeared to be somewhat erratic in 3N, probably because of incomplete sampling of the stock prior to the mid-1960s.Average size at age increased gradually from the early 1950s to the 1970s apparently because of increased growth rate in the initial 2 or 3 yr of life. Coupled with the increased size at age were significant declines in the age at sexual maturity.Significant correlations were found between stock abundance and asymptotic length (L∞), and size at age 5 and 10 in Division 3L and while positive trends could be demonstrated between some of these and mean bottom temperature, the correlations were not significant.
Cholesterol Requirements of Juvenile American Lobster (Homarus americanus)
Authors: Castell John D. , Mason Edgar G. , Covey Jane F.
Published: April 2011

In preliminary feeding trials with juvenile American lobsters (Homarus americanus) there were some differences in growth and survival that appeared to be related to deletion or addition of cod liver oil, mineral salts, vitamins, and glucosamine. However, the results were questionable due to deficiency of dietary cholesterol. Only when 1% cholesterol was added to the control diet was growth and survival achieved similar to that of lobsters fed brine shrimp. The optimum or required level of cholesterol was found to be approximately 0.5% of the dry weight of the diet.
Young Witch Flounder, Glyptocephalus cynoglossus, on the Slope off Virginia
Authors: Markle Douglas F.
Published: April 2011

Young witch flounder, Glyptocephalus cynoglossus, 11–25 cm TL, are abundant on the continental slope off Virginia. The Virginian slope may be a major nursery area for 1- to 3- or 4-yr-old witch flounder spawned by one or more northern stocks. Shelf water circulation patterns are considered as a possible mechanism for the passive dispersal of larvae.
Comparative Toxicity of Larval Lampricide (TFM: 3-trifluoromethyl-4-nitrophenol) to Selected Benthic Macroinvertebrates
Authors: Maki Alan W. , Geissel Lester , Johnson Howard E.
Published: April 2011

The acute toxicity of larval lampricide (TFM: 3-trifluoromethyl-4-nitrophenol) to 35 species of benthic macroinvertebrates was determined in 96-h flow-through tests. The 96-h LC50 values range from 2.1 mg/liter for blackfly larvae, Simulium pugetense, to values in excess of 38.0 mg/liter for species with heavy exoskeletons: crayfish (Orconectes propinquus), dobsonfly larvae (Chauloides sp), and dragonfly naiads (Ophiogomphus sp.) Younger individuals of the clam (Ligumia sp.) and the mayfly nymph (Ephemerella cornuta) were 2 to 1.5 times more sensitive than larger individuals of the same species. Early emergence of adults and increased locomotor activity were observed among some organisms exposed to sublethal concentrations.
The Fisheries Research Board of Canada — Seventy-Five Years of Achievements
Authors: Ricker W. E.
Published: April 2011

The idea of having government research supervised by a group of knowledgeable individuals outside of the government service began, in Canada, in the field of aquatic science and fisheries. In 1898 an honorary Board of Management was set up to establish and manage a biological station on the Atlantic coast. As this Board’s responsibilities increased it was renamed the Biological Board of Canada, and finally the Fisheries Research Board of Canada. Starting in 1973 the Board ceased to have direct responsibility for the management of research stations, but it continues as an advisory body.During the period 1898–1972 the Board has provided facilities for original research on aquatic animals and plants and on the waters they inhabit, much of it done by scientists from universities and museums; it has solved many problems faced by governments in locating, evaluating, managing and increasing fish stocks; and it has assisted the fishing industry with improved techniques for catching, handling, processing and marketing its products. The immediately useful results of the Board’s work have been made available to the Canadian community through reports, publicity and personal contacts. Details of scientific discoveries have been published in the Board’s Journal and other outlets, while results of research done in other countries have been sifted and interpreted for their application to the Canadian scene.
Color Atlas of the Diseases of Fishes, Amphibians and Reptiles.
Authors: Bell Gordon R.
Published: April 2011

not available
Algal Physiology and Biochemistry
Authors: Antia Naval J.
Published: April 2011

not available