bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Feeding of Some Medusae and Chaetognatha
Authors: Fraser J. H.
Published: April 2011

The feeding behaviour of eight species of medusae was studied; total food consumed, rates of digestion, and growth rate were noted, especially in Cyanea and Aurelia.Aurelia up to 5 cm diam can accept a wide range of size of food organisms obtained by filtering sea water through the curtain of tentacles during pulsation, whereas most other species find their food by random contact with the tentacles. In Bougainvillia it is the dichotomously branched oral tentacles that capture the food. The apparent selectivity of Sarsia in feeding on copepods is shown to be a physical effect produced by its method of swimming. Leuckartiara can catch and eat active organisms larger than itself. None of the medusae examined showed any reaction to artificial stimulation by a vibrating probe.The method of transfer of food from the tentacles to the mouth is closely associated with the structure of the medusa. Long trailing tentacles contract and lift food towards the mouth and if the manubrium is long it can be manipulated to pick off the food from the tentacles. If the tentacles are short the umbrella edge folds inwards towards the mouth. If there is no manubrium, as in Staurophora, the cruciform stomach can accept food at any point.Larval fish are important in the diet of most medusae and rough estimates are given of a probable consumption of 50–250 larval fish per hydromedusa, about 450–500 by each Aurelia, and in the order of 15,000 by Cyanea. A conversion factor is given for food eaten by medusae of 37%, though this is based on only few data.Following the work of Horridge and Boulton (Proc. Roy. Soc. (Ser. B) 168: 413–419, 1967), who found that Spadella could be artificially stimulated to bite vibrating probes, similar experiments were made with Sagitta elegans. Although the chaetognaths were successfully kept alive the probes produced no feeding reaction. The methods are outlined for the benefit of others wishing to continue such investigations.
Cortisol Secretion Rate in Gonadectomized Female Sockeye Salmon (Oncorhynchus nerka): Effects of Estrogen and Cortisol Treatment
Authors: Donaldson Edward M. , Fagerlund Ulf H. M.
Published: April 2011

Gonadectomized female sockeye salmon (Oncorhynchus nerka) were injected intramuscularly with cortisol, estradiol, estradiol cypionate, or peanut oil for 8 weeks. The metabolic clearance rate of cortisol was determined by the single injection technique and calculated from the formula for a two pool system. The cortisol secretion rate was determined from the metabolic clearance rate and the plasma cortisol concentration.The volume of distribution of cortisol in the inner compartment (V1) and the outer compartment (V2), the metabolic clearance rate (MCR), the resting secretion rate (S), and the resting plasma cortisol concentration were all significantly higher in the estradiol-injected group than in the peanut oil-injected control group, and the plasma cortisol concentration at the end of the experiment was lower. V1, MCR, and S were also significantly higher in the estradiol cypionate-injected group. There were no significant differences between the cortisol-injected group and the peanut oil-injected control group or in the biological half life of cortisol between any groups.There were no significant changes in the red colour of the flesh or in body weight during the experiment. However, the cortisol-injected group did show the largest weight loss.
Maturity and Fecundity of Walleyes from the Eastern and Western Basins of Lake Erie
Authors: Wolfert David R.
Published: April 2011

Of 2427 walleyes (Stizostedion vitreum vitreum (Mitchill)) examined from Lake Erie in 1964–66, no females were mature at ages below III and all were mature at age V. All male walleyes from the eastern basin were mature at age II, and those from the western basin at age III. Females from the western basin matured at a shorter length and a younger age than those from the eastern basin. Males from the western basin, on the other hand, matured at a longer length and greater age than those from the eastern basin.Egg production, which was estimated for 60 walleyes from the eastern basin and 78 from the western basin, ranged from 48,000 to 614,000. The number of eggs increased rapidly with increase in total length, but the relation between fecundity and weight was almost linear. Walleyes from the western basin were much more fecund for any given length, weight, or age than those from the eastern basin. Weight was the most accurate indicator of fecundity. The mean diameter of eggs from 32 ripe walleyes was 1.72 mm. Little relation existed between egg diameter and length or age of fish.
Decapod Crustacea of the Beaufort Sea and Arctic Waters Eastward to Cambridge Bay, 1960–65
Authors: Squires H. J.
Published: April 2011

The CGS Salvelinus collections of decapod crustaceans from south Beaufort Sea to Cambridge Bay in 1960–65 comprised 1830 specimens of 15 species. Five of the species were not previously recorded from this area. Most abundant species were Sabinea septemcarinata and Eualus gaimardi. Eualus macilentus and E. stoneyi were confined to Bathurst Inlet. Westward setting currents along the Beaufort Sea coast mediate against incursions by Pacific species but Chionoecetes opilio, Hyas coarctatus alutaceus, and a species of Pagurus seemed to have overcome this condition. The species in which the highest percentages of females presumably reproduced annually were Spirontocaris phippsi, S. spinus, and S. septemcarinata.
Isopropanol–Water Azeotrope as Solvent in the Production of Fish Protein Concentrate from Herring (Clupea harengus)
Authors: Dambergs N.
Published: April 2011

In the process of the production of fish protein concentrate (FPC) the isopropanol is recovered, most economically, in the form of an aqueous azeotrope. It has been demonstrated that the azeotrope can be used effectively for processing FPC avoiding the necessity of dehydration.
Range Extension of Flag Rockfish (Sebastodes rubrivinctus) to Aleutian Islands
Authors: Best E. A. , Eldridge Peter J.
Published: April 2011

During August 1967, 12 specimens of Sebastodes rubrivinctus were collected from the Pacific Ocean off Amchitka Island, Alaska. This is a westward extension of their known range from the Gulf of Alaska.
Demersal Fish Explorations in the Northeastern Pacific Ocean — An Evaluation of Exploratory Fishing Methods and Analytical Approaches to Stock Size and Yield Forecasts
Authors: Alverson Dayton L. , Pereyra Walter T.
Published: April 2011

A series of demersal fish studies were conducted throughout the northeast Pacific Ocean. The aims of these exploratory fishing surveys were: (1) to describe the zoogeographic distribution patterns of the animals encountered and the relationship of such patterns to observed environmental features; (2) to determine their relative abundance in time and space and to each other and their vulnerability to sampling gears; and (3) where possible, to establish approximations of the magnitude of important or potentially important commercial species together with estimates of the physical yields that these resources might provide. A general review is given of U.S. demersal fish explorations in the northeast Pacific Ocean along with the methodology employed. Methods for estimating standing stocks based on fish densities determined from catch-per-unit-of-effort data are given. Using this procedure, estimates have been made for the more abundant demersal fish forms in the northeast Pacific. Means of determining yield possibilities are suggested, based on natural mortality rates and standing stock sizes. This method assumes that the maximum sustainable catch will range from.4 to.5 of the virgin stock size times the natural mortality. Finally the authors evaluate the reliability of exploratory fishing surveys based on subsequent development of commercial fisheries in the northeast Pacific. The data appear to have provided a good basis for describing the distribution and availability of important demersal fish elements in this area. Although estimates of yield potentials are still being studied, the history of fisheries development has, to date, followed quite well what might have been expected as a result of the preliminary yield forecasts.
Reproductive Behaviour of the Blackspotted Stickleback, Gasterosteus wheatlandi
Authors: McInerney John E.
Published: April 2011

The reproductive biology of the blackspotted stickleback (Gasterosteus wheatlandi) closely parallels that reported elsewhere for G. aculeatus, with certain noteworthy exceptions. Gasterosteus wheatlandi nests in brackish water of low salinity rather than in fresh water. The mature males are gold on the dorsal and lateral surfaces and white on the ventral surface with an irregular series of black spots along the ventro-lateral surfaces of the tail stalk, in contrast to the blue and red highlights of mature colouration in G. aculeatus males. There are marked differences also in the behaviour by which males of the two species lead females to the nest. In the blackspotted stickleback leading consists in an intricate series of movements along the substrate, the male in a head-down position and quivering, the female in a head-up posture with her snout touching the male between his pelvic spines; in contrast, G. aculeatus males simply swim to the nest entrance, the female following with no physical contact. Reproductive isolation between the two species probably depends on breeding habitat separation and female recognition of species-specific male colour patterns. When these fail, incompatible leading behaviours constitute an effective block to interspecific hybridization. Parental fanning in G. wheatlandi resembles that in G. aculeatus except that average bout duration is substantially less. Vertical quivering, a post-spawning activity of unknown function, is unique to G. wheatlandi.
Buoyancy of Atlantic and Pacific Herring
Authors: Brawn Vivien M.
Published: April 2011

Pacific and Atlantic herring after adjustment to water 36 cm deep had sinking-factors between 1000 and 1008 and showed an inverse relationship between oil content and swimbladder volume up to 12% oil. At higher oil contents a swimbladder volume between 2.6 and 3.0% of total body volume was maintained. The mean volumes and densities of various components of the Pacific herring held in captivity were: swimbladder gas 4.1% of total volume,.0013 g/ml; oil 3.5%,.926 g/ml; scales 0.5%, 1.966 g/ml; skeleton 1.2%, 1.993 g/ml; rest of fish 90.6%, 1.057 g/ml. These components on the average exerted upward forces of 41.4 and 3.3 dynes/ml of fish due to gas and oil, and downward forces of 4.6, 11.2, and 32.1 dynes/ml due to scales, skeleton, and the rest of the fish respectively. Under natural conditions herring usually have high oil contents so the relationship observed here suggests they have low swimbladder volumes. This combined with a duct direct from the swimbladder to the exterior and the lack of gas secretion would give the herring freedom of vertical movement and a low change of sinking factor with depth.
Electroencephalographic Olfactory Responses in Adult Salmon to Waters Traversed in the Homing Migration
Authors: Oshima Kiyoshi , Hahn William E. , Gorbman Aubrey
Published: April 2011

By infusing various natural waters into noses of homing salmon (Oncorhynchus tshawytscha and O. kisutch) and recording electroencephalographic (EEG) patterns from the olfactory bulb, data were collected showing responsiveness to waters along the freshwater migratory route. The largest responses always were evoked by the home water for each of the three spawning groups. Generally, the responses to various waters along the migrating route were equivalent, or did not vary in any recognizable progression. Accordingly, it does not seem that homing salmon are following a single olfactory clue in increasing concentration. Instead, they appear to be responding olfactorily to individual loci along the route.
Composition and Horizontal Distribution of Crustacean Plankton in Lake Ontario
Authors: Patalas K.
Published: April 2011

The horizontal distribution of planktonic crustaceans was determined in Lake Ontario at monthly intervals from June to October 1967, based on net hauls from 50 to 0 m at 32–62 stations. A separate study conducted over a 24-hr period at one station showed that on the average 90% of the zooplankters occupied the 0–50-m stratum through which the net was hauled. Eleven species of copepods and 11 species of cladocerans were found. The most abundant forms were Cyclops bicuspidatus thomasi, Daphnia retrocurva, Bosmina longirostris, Bosmina coregoni coregoni, Tropocyclops prasinus mexicanus, and Ceriodaphnia lacustris. Most species appeared in the collections during June–July in the eastern part of the lake with abundance patterns later moving westward, contrary to the general movement of wind and water. At the time of maximal population density there was a strong positive correlation between zooplankton abundance and heat content of the water column from 0 to 25 m. The eastern part of the lake averaged 1.7 times more specimens/cm2 than the western part of the lake. Upwelling was responsible for low numbers of zooplankters along the northwestern shore. Abundance patterns similar to generalized current flows were observed in the northern and southern parts of the lake. Flow from the Niagara River was associated with increased abundance of zooplankters in spring and summer, but decreased abundance in autumn. A detailed study of the abundance and distribution of zooplankton offshore from Toronto Harbour showed that harbour water does influence zooplanktonic populations in the vicinity. Temperature and depth of the epilimnion as influenced by the general direction of wind motion were key factors in understanding the zooplanktonic community of Lake Ontario.
Effect of the Organophosphate Dylox on Rainbow Trout Larvae
Authors: Matton Pierre , LaHam Quentin N.
Published: April 2011

Organophosphate poisoning in fish and mammals has always been associated with the inhibition of acetylcholinesterase in both neuromuscular and brain tissues. This inhibition resulted in the apparent death of the organisms by asphyxia. Rarely have other effects been reported.In the present study, 1-inch rainbow trout larvae were treated for 16 hr with from 10 to 100 ppm Dylox, or for 40 hr with 5 ppm. This treatment produced a marked acetylcholinesterase inhibition that was reflected by their abnormal behaviour patterns. Histological examination revealed pathological changes in the heart, liver, blood cells, pseudogills, and muscular tissues; this pathology could not be explained on the basis of acetylcholinesterase inhibition.
Microsporidial Infection of English Sole, Parophrys vetulus
Authors: Wellings S. R. , Ashley L. E. , McArn G. E.
Published: April 2011

Infection of two English sole, Parophrys vetulus, probably by Glugea hertwigi, is described. Numerous Glugea cysts (xenomas), measuring 0.5–1.0 mm in diameter, were located throughout the entire intestine distal to the stomach and including the pyloric caecae. A few cysts were located in the mesentery, pancreas, and liver. Microscopically, the cysts were composed of a hyaline connective tissue capsule, enclosing an intermediate layer of syncytium and a central mass of mature spores.
Stomach Contents of Juvenile Pacific Salmon in Chatham Sound and Adjacent Waters
Authors: Manzer J. I.
Published: April 2011

Stomach contents of young Pacific salmon in Chatham Sound and adjacent waters of northern British Columbia from June through August indicated interspecific differences in the kinds of organisms consumed. Pinks (Oncorhynchus gorbuscha) and chums (O. keta) were mainly planktophagous, copepods and Larvacea (Oikopleura spp.) being most important; cohos (O. kisutch) were piscivorous, herring larvae (Clupea spp.) and sand lance (Ammodytidae spp.) being important; sockeye (O. nerka) were mainly planktophagous but fish also were important. With pinks and chums, while they were still relatively abundant along the beaches, the dominant food item progressively changed from copepods in the southern areas to Larvacea in the northern areas.
Otter Surface Sampler: a New Neuston Net
Authors: Sameoto D. D. , Jaroszynski L. O.
Published: April 2011

A new surface sampler for the collection of zooplankton and ichthyoplankton is described. The advantages it has over other neuston samplers are that it can be towed at speeds up to 11 knots, can be used in choppy waters, is easily handled by one man, has no structures preceding the mouth of the net, and is easy and inexpensive to construct.
Maintenance of the Life Cycle of Ligula intestinalis in the Laboratory
Authors: Orr T. S. C. , Hopkins C. A.
Published: April 2011

Techniques for the maintenance of the life cycle of Ligula intestinalis in the laboratory are described. Fertile eggs were produced by adult cestodes 72 hr after ducklings were fed with infective plerocercoids. Eggs were extracted by sieving and washed by decanting prior to incubation in water for 10 days at 25 C. A bright light stimulated developed eggs to hatch, and the emergent coracidia were fed to the copepods Diaptomus fragilis and Mesocyclops leuckarti. Infective procercoids were present in the haemocoel of copepods after 10 days at 25 C. Plerocercoids developed in tropical cyprinid fish, e.g., Danio malabaricus, which were infected by exposure to infective copepods.
Effect of Hematin Compounds on the Development of Rancidity in Muscle of Cod, Flounder, Scallops, and Lobster
Authors: Castell C. H. , Bishop D. M.
Published: April 2011

Hemoglobin, catalase, myoglobin, and inorganic iron were added to blended muscle from cod, flounder, scallops, and lobsters to determine the effects of these various forms of iron on the oxidation of the muscle lipids as indicated by increased malonaldehyde and rancid odours. Hemoglobin and catalase were very active catalysts; myoglobin was relatively inert. Scallop muscle was slightly more susceptible to hemoglobin-induced rancidity than muscle from cod or flounder; lobster muscle was highly resistant. There was a difference in the odours accompanying the development of rancidity after the addition of free Fe++ and hemoglobin-bound Fe++. An increase in the free fatty acid content of the muscle retarded the hemoglobin-induced rancidity. Certain free amino acids, notably tryptophane and proline, also had an inhibitory action, whereas other amino acids had a prooxidant effect.
Progressive Changes in the Ventral Aorta of the Carp, Cyprinus carpio
Authors: Eastman Joseph T.
Published: April 2011

Early arteriosclerosis was found in the curved region of the ventral aorta of the carp, Cyprinus carpio Linnaeus, older specimens showing a greater degree of involvement than younger specimens. The progressive pathological changes are attributable to the length of time that a particular set of hemodynamic conditions, resulting in a suction on the inner wall of the arterial curve, have been operating.
Effects of Fluctuations of Lead, Temperature, and Dissolved Oxygen on the Growth of Brook Trout
Authors: Dorfman D. , Whitworth W. R.
Published: April 2011

Slug doses of lead administered once a day 5 days/week to brook trout exposed to simultaneous diel fluctuations of dissolved oxygen and temperatures showed that concentrations of 25 mg/liter of lead reduced growth. Concentrations of 15 mg/liter had little apparent effect and concentrations of 10 mg/liter had no deleterious effects on growth.
Effect of Temperature on the Activity of Glyceraldehyde-3-Phosphate Dehydrogenase; a Comparison of Halibut and Rabbit Enzymes
Authors: Farrington John W. , Baker Dwight L.
Published: April 2011

The halibut enzyme activity was found to be less affected by temperature change. The energy of activation of the reaction catalyzed by these two enzymes differed by a factor of 2. Both enzymes catalyzed reactions that had a constant energy of activation over the range of 5–35 C.
A Record of Hermaphroditism in Lake Whitefish, Coregonus clupeaformis
Authors: Chen Maynard Y.
Published: April 2011

A rare case of hermaphroditism in lake whitefish was observed. The ovo-testis was found in the left gonad with an unusual dorsal-ventral relationship between the two parts. The male portion contained both wide tubules densely packed with germ cells, bordering on the ovarian tissue, and narrow tubules, with fewer germ cells, in the rest of the testis. The female portion appeared to contain only atretic eggs. There was a clear demarcation between the male and female portions of the ovo-testis.
Effect of Seawater Chilling on Landed Quality of Scallop Meat
Authors: Varga S. , Blackwood C. M.
Published: April 2011

Landed quality of scallop (Placopecten magellanicus Gmelin) meat was improved by chilling in sea water prior to bagging and icing. The results suggested an increase in ice storage time of 2–9 days on trips of 14 or 15 days to Georges Bank and longer on trips to grounds where water temperatures are higher than 60 F.
Polymorphic Serum Esterases in Two Species of Freshwater Fishes
Authors: Nyman O. L.
Published: April 2011

Two simple, genetically determined serum esterase polymorphisms, suited for population analysis, are described in two species of freshwater fishes, white bream (Abramis blicca B.) and ruff (Acerina cernua L.). In both instances the synthesis of the enzyme bands was found to be controlled by two allelic codominant genes, which also in both instances were kept in equilibrium. Gene frequency data are presented from one population of each species.
Modifications in Sampling Procedures as Applied to Studies on the Bacteria and Tubificid Oligochaetes Inhabiting Aquatic Sediments
Authors: Brinkhurst R. O. , Chua K. E. , Batoosingh E.
Published: April 2011

The KB corer has many advantages over other bottom-sampling devices including some other coring tubes. It may be used to obtain reliable estimates of the standing stock of benthic invertebrates inhabiting soft sediments and of their spatial distribution in lakes and rivers. It may also be used for studies of the vertical distribution of animals and bacteria, and could be used for a wide variety of studies on sediments. Multiple-unit versions have been built and operated, thus overcoming the size limitation imposed by the basic design. This paper communicates some results obtained using this sampler.
Records of Mesopelagic and Other Fishes from the Canadian Atlantic with Notes on their Distribution
Authors: Halliday R. G. , Scott W. B.
Published: April 2011

The following 35 species are recorded from the Canadian Atlantic: Bathylagus euryops, Cyclothone spp., Maurolicus muelleri, Argyropelecus lychnus lychnus, Chauliodus sloani, Stomias boa ferox, Chlorophthalmus agassizi, Benthosema glaciale, Ceratoscopelus maderensis, Diaphus dumerili, D. termophilus, Hierops arctica, Hygophum hygomi, H. macrochir, Lampanyctus alatus, L. festivus, L. pusillus, Lobianchia dofleini, Myctophum punctatum, Notolychnus valdiviae, Notoscopelus krøyeri, N. resplendens, Symbolophorus veranyi, Notolepis rissoi krøyeri, Nemichthys scolopaceus, Nessorhamphus ingolfianus, Polymixia lowei, Trachurus trachurus, Decapterus macarellus, Stenotomus chrysops, Lycodes esmarki, Centrolophus niger, Psenes maculatus, IIelicolenus dactylopterus, and Icelus bicornis. The composition of the mesopelagic fauna of the Slope Water region and the vertical migrations of its components are discussed.
Reaction of Free Fatty Acids with Protein in Cod Muscle Frozen and Stored at −29 C after Aging in Ice
Authors: Anderson Margaret L. , Ravesi Elinor M.
Published: April 2011

Freezing and holding cod muscle in the frozen state favored the association process that involves protein–free fatty acid (FFA) complex formation and begins during aging in ice. Changes in protein extractability, in ultracentrifugal patterns of protein extracted, and in phase contrast micrographs of inextractable muscle fragments were followed in muscle that had been aged in ice to produce various contents of FFA and then frozen and held at −29 C. After 11 months, these changes, which took place largely during the first week of storage, were comparable with those that occur when the FFA are formed during frozen storage. The results were consistent with a reaction rate that was greater at −29 C than at temperatures a few degrees above 0 C.
Temperature Conditions in the Gulf of Maine and Adjacent Waters During 1968
Authors: Colton Jr. John B.
Published: April 2011

Surface-water temperatures at Boothbay Harbor, Maine, in 1968 were appreciably higher than in 1967. This check in the recent coastal cooling trend was reflected in offshore surface and subsurface temperature conditions and was accompanied by a shift in the relative position of Coastal and Slope Water along the edge of the Continental Shelf.
Age and Size of Steelhead Trout in the Babine River, British Columbia
Authors: Narver David W.
Published: April 2011

Scales were collected from adult summer steelhead trout taken in 1967 and 1968 in an increasingly important sport fishery on the Babine River. The most common total age was 3.2 (73% in 1967 and 60% in 1968), and the second most common age was 3.3. The males tended to remain a year longer in the ocean than did females before first maturation. Four of 121 (3.3%) scales, all from female steelhead, indicated the fish had spawned once previously. The male to female ratio in the sport fishery was 1:1.33. Mean length at time of smolt outmigration as estimated from scales from 3.2 fish was 190 mm. These results are compared with what is known for other British Columbia steelhead stocks.
A Stochastic Model of Interpopulation Dynamics in Marine Ecology
Authors: Riffenburgh Robert H.
Published: April 2011

A nonstationary Markov chain was developed to analyze and model the passage of energy through an ecological system composed of the Pacific sardine, the northern anchovy, their competitors, their predators, and their prey; then to carry the model forward through time projecting the biomasses of the relevant species if anchovy or hake fisheries, or both, are begun. The model seemed to agree adequately with observed data.The hypothesis of some earlier work of the author that the abundances of populations could be completely controlled by fishing intensities was rejected. Although no measure was made of the robustness of the ecosystem, it was concluded to be relatively impervious to artificial pressures, although there was seen a measurable boundary beyond which the ecological interactions became unstable and the system collapsed.Specifically, based on 1950–59 data, the sardine catch was projected to stabilize in the vicinity of 20 metric kilotons per year. Overfishing did not seem to have been a cause of the sardine "disappearance." To maximize sardine catch, the introduction of anchovy and hake fisheries with annual catches limited to certain percentages (depending on the maximizing criterion) of abundances would double or triple sardine catch and stabilize the fishing industry, but sardines could not be reinstated as the most abundant species as a result of selective fishing. To maximize the combined catch of the three fisheries, annual catches of 30% and 20% (for all criteria) of abundances of anchovy and hake, respectively, would yield nearly 1800 metric kilotons of fish, although most of it would be of less commercial interest than the sardine.
Extension of Range for Manayunkia aestuarina (Polychaeta: Sabellidae) to British Columbia
Authors: Light William J.
Published: April 2011

The brackish water polychaetous annelid Manayunkia aestuarina (Bourne) is newly recorded for North America and constitutes the second species of the genus known to occur on this continent. Its range is extended from the British Isles, the Baltic and North Sea areas, and the Barents Sea (Kola Fjord).
Alpha-Glycerophosphate Dehydrogenase As an Index of Iced-Storage Age of Fresh, Gutted Haddock (Melanogrammus aeglefinus)
Authors: Gould Edith
Published: April 2011

A new test is described for judging the iced-storage age of unspoiled gutted haddock, from early loss of quality to the first gross signs of spoilage. The test is a measure of the changing properties of alpha-glycerophosphate dehydrogenase in tissue fluid with time after death, and is interpreted as an indication of leaching of tissue during the first 7 days of storage. Such functional changes in an enzyme system are a particularly sensitive criterion of freshness in fish during the first 4 or 5 days of iced storage.
Further Observations on the Response of Rainbow Trout,Salmo gairdneri, to Overhead Light
Authors: Kwain Wen-hwa , MacCrimmon Hugh R.
Published: April 2011

The response of rainbow trout (Salmo gairdneri Richardson) to overhead light changed with the growth of the fish. No response was evident until the age of 7 months, after which the response became more pronounced with age. Trout exhibited a significant preference for the darkest chamber when given a choice of five intensities of artificial light. Minimum light threshold for 10-month-old fish was between 0.01 and 0.005 lux. However, 24-month-old fish had a lower level of light threshold between 0.005 and 0.001 lux.
Further Analysis of Ration and Growth Relationship of Plaice (Pleuronectes platessa)
Authors: Rafail Samir Zaky
Published: April 2011

Evidence is given that the average daily rations (R) and fortnightly growth increments (ΔW) of six weight groups of Pleuronectes platessa fed on Mytilus edulis are related as in the power equation ±(ΔW−ΔWm) = ±b(|R–Rm|)B. Rm is the daily ration associated with the growth increment (ΔWm) at maximum growth efficiency; b and B are parameters. The power B has a mean value of about 0.5 and shows significant deviations from the mean especially in the case of smaller fish.
Fibrous and Cystic Lesions in the Ovaries of Aged Atlantic Cod (Gadus morhua): a Preliminary Report
Authors: Wiles Michael
Published: April 2011

Ovarian stromal fibrosis occurred in four Atlantic cod (Gadus morhua L.) from the northeastern Gulf of St. Lawrence (49°07′N, 59°18′W) and off Fox Harbour, Labrador (52°18′N, 55°52′W), with accompanying cystic lesions in two specimens.Externally the ovaries varied. Specimen 1 (115 cm fork length, age 18 years) possessed clear areas (0.5–1.5 mm) where the underlying stroma was relatively thin. Specimen 2 (107 cm, 19 years) possessed scattered cream or yellow nodules (< 1 mm) and coalesced nodules (1.5–2.0 mm). Specimen 3 (118 cm, 19 years) had many colourless fluid-filled cysts (1.5–2.0 mm) and a few larger cysts (5.0 × 7.5–7.0 × 12.0 mm), the latter confined to the tapering posterior regions of the ovary. Specimen 4 (99 cm, 16 years) possessed large (up to 8 mm) multilocular cysts anteriorly.Stromal fibrosis occurred to varying degrees in each specimen, containing predominantly fibrinoid as identified by Mallory's PAH, Weigert's fibrin test, and retention of a PAS-positive reaction after incubation in alkaline trypsin. Widespread degeneration of ovigerous lamellae occurred in specimens 3 and 4.The condition of specimens 3 and 4 suggests involutional ovarian stromal fibrosis, but the endocrine studies necessary to confirm this opinion were not performed.
Night Feeding of Brown and Rainbow Trout in an Experimental Stream Channel
Authors: Jenkins Jr. Thomas M.
Published: April 2011

This study sought to determine if stream-living brown and rainbow trout (Salmo trutta and Salmo gairdneri) will feed on drifting terrestrial insects at night. Groups of fish were confined in segments of a rocky-substrate mountain stream, and marked ants were introduced to the current from observation towers equipped with feeding tubes. After the last introductions of an experiment, the fish were removed and their stomachs were examined for marked ants.Although fish of both species fed at night, they appeared to take a smaller percentage of the ants provided than did day-feeding groups studied for comparison. Fish feeding under bright moonlight and starlight captured introduced ants at about the same rates. The results suggest that trout in the type of stream studied feed or are in feeding readiness at nearly all hours of the day or night, at least in the summer months.
An Analysis of Variation of Insecticide Residues in Landlocked Atlantic Salmon (Salmo salar)
Authors: Anderson Richard B. , Fenderson Owen C.
Published: April 2011

High variation in yearly samples of insecticide residues found in landlocked salmon from Sebago Lake, Maine, has necessitated an evaluation of sampling methods and an investigation of causes of variation. A sample of 59 male salmon, composed of ages III+, IV+, and V+, and representing fish in poor and good body condition was collected from a spawning run in the fall of 1967 and analyzed for DDT, DDD, DDE, dieldrin, and fat content. Levels of insecticide residues were found to be highly dependent on age and fat content. DDD and DDE increased with age and fat content, and dieldrin increased with fat content. Age and fat content were interdependent in their effects on DDT levels. DDT was significantly higher in high-fat than in low-fat fish at ages III+ and IV+ but not at age V+, showing a decrease with age among fish with high fat content and remaining constant with age among fish with low fat content. It is recommended that completely random selection of fish for insecticide analyses be abandoned in favor of stratification by sex, age, and fatness. Some of the possible causes of variation in insecticide content of salmon are discussed.
Productivity of Macrophytes in Marion Lake, British Columbia
Authors: Davies Gordon S.
Published: April 2011

The in situ productivity of both the phytoplankton and the macrophytes in Marion Lake, B.C., was determined from April 1966 through September 1966, by using 14C techniques. The uptake of NaH14CO3 was measured in selected macrophytes by enclosing them in Plexiglas chambers. These plants were then combusted in oxygen, and the 14CO2 was absorbed in toluene-POPOP-ethanolamine. Radioassay was accomplished by liquid scintillation. In addition to the 14C method, an organic weight method was used to measure macrophytic productivity.The productivity of the macrophytes was always higher than that of the phytoplankton. There was a considerable difference in the estimates of the macrophyte productivity arrived at by the two different methods, and reasons for this are discussed.The total productivity of the lake is very low when compared with lakes of similar latitudes because of low phytoplankton productivity. It is concluded that in Marion Lake the macrophytes are more important primary producers than the phytoplankton.The difficulty of comparing data between this and other studies is discussed, and the need for standardization of methods is emphasized.
Long-Term Effects of Diet on the Biology of the Lake Trout and the Fishery in Lake Opeongo, Ontario
Authors: Martin N. V.
Published: April 2011

From 1936 to 1965 food content was examined in 17,171 Lake Opeongo lake trout (Salvelinus namaycush). The diet is analysed from the point of view of frequency of occurrence of foods, their weight, feeding activity of trout, size of trout and size of food, and seasonal and annual changes in food habits.In the late 1940's and early 1950's perch, Perca flavescens, largely disappeared from the diet. The lake trout initially turned to lake whitefish, Coregonus clupeaformis, and then to the cisco, Coregonus artedii, introduced into Lake Opeongo in 1948.As a result of these dietary changes lake trout are now heavier and rate of growth has improved. Age and size at maturity is later and there are fewer infertile fish. Egg counts, egg size, and ovary weights are now greater, particularly in the medium-sized lake trout.In the fishery the average weight of individual trout taken has almost doubled. About 25% more of the immature stock is exploited by the recent fishery. The harvest and catchability of lake trout has remained generally constant on a numerical basis but show an improvement on a poundage basis in the more recent years. The possible effects of these changes on the character of the fishery are discussed.
Three Computer Programs: Back-Calculation, Condition Factor, and Stomach Content, CDC 3600 Fortran/Format
Authors: Mawson J. C. , Reed R. J.
Published: April 2011

Three programs were developed to be used on the CDC 3600 computer at the University of Massachusetts: back-calculation, condition factor, and stomach content. They are written in standard Fortran IV notation, which can be adapted to any computer setup that accepts Fortran IV and has at least the storage capacity listed for each program. Instruction sheets and sample output can be secured from either author.
Fish Chromosome Preparation: Air-Dried Displays of Cultured Ovarian Cells in Two Killifishes (Fundulus)
Authors: Chen T. R.
Published: April 2011

A relatively simple and reliable in vitro methodology for fish chromosome study is described. A single cell suspension obtained by trypsinizing ovarian tissue was cultured for 5–7 days at 31 C. The cells were treated with colchicine and hypotonic solutions then fixed in acetic-alcohol fixative. Air-dried preparations were made from these cells and were stained with aceto-orcein.Numerous metaphase plates unmarred by overlapping chromosomes were recovered and high quality karyograms were available for detailed karyotypic analysis. The general similarity of squash and air-dried karyotypes suggests that short-period cell culture preserves natural karyotypes.
Physical and Chemical Limnology of Two Mountain Lakes in Banff National Park, Alberta
Authors: Anderson R. Stewart
Published: April 2011

Limnological investigations of an alpine and a lower subalpine lake in Banff National Park from 1966 to 1968 showed that vernal circulation may not extend to the bottom in either lake and that complete autumn circulation may persist for several weeks in both lakes. Winter heat incomes were similar in the lakes, but the summer heat income was much lower for the alpine lake due to heat lost through water renewal. Thermal stratification was more clearly defined in the subalpine lake each year than in the alpine lake. When well-defined chemical stratification occurred, it was short-lived in both lakes. With the exception of phosphate, which was highest in spring and early summer, most changes in chemical composition appeared related to dilution. Very low oxygen concentrations occurred in the bottom water strata of the subalpine lake, but depletion was never severe in the alpine lake. Of the incident visible light 16% penetrated ice and snow cover (1 m) on the alpine lake, but less light reached the water of the lower subalpine lake because of cloudy ice and deeper snow. The trophogenic zone extended to the bottoms of both lakes (about 13 m) for at least part of each year.
Influence of Body Weight on Chronic Oral DDT Toxicity in Coho Salmon
Authors: Buhler Donald R. , Shanks W. E.
Published: April 2011

Median Survival Time was directly proportional to body weight in young coho salmon of the same age that were fed a diet containing technical DDT. Supplementation by additional feeding with DDT-free diet prolonged the lifespan of these fish but the Median Survival Time remained a direct function of body weight.The primary effect of body size on lethality was to control the rate of DDT intake by the fish. The smallest fish consumed the greatest amounts of diet and, consequently, these fish received the highest milligram per kilogram doses of DDT.In addition, however, the smaller salmon succumbed to a lower milligram per kilogram cumulative lethal dose than did the larger fish, perhaps because the smallest fish contained a lower percentage of lipid and thus failed to provide for adequate storage detoxification of the DDT.
A Theory Concerning the Distance Travelled by Animals Entering the Drift of a Stream
Authors: McLay Colin
Published: April 2011

Stream bottom animals were introduced into a stream by disturbing the gravel at increasing distances upstream from a drift sampler. The relationship between the number of animals arriving at the sampler and distance of origin of the animals was found to be Nx = N0 e−RX where N0 is the number of animals introduced, R is the rate of return to the gravel of the animals, and X is the distance upstream from the sampler. The maximum distance travelled was 45.7 m and the mean distance 10.7 m. The values of R for individual species ranged from 0.0517 to 1.962 and values of the mean distance travelled from 19.3 to 0.5 m. Specific differences could be accounted for by differences in structure or behaviour of the animals.From these observations, a model of stream drift is developed. Two previously published experiments are shown to conform to model relationship: (1) recovery of drift density downstream from a blockage in the experiment of Waters (Ecology 46: 327–334, 1965); and (2) distribution of times taken to regain a foothold on the substrate by mayfly nymphs released into a current (Madsen, Flora Fauna 72: 148–154, 1966; Hydrobiologia 31: 337–349, 1968).Since a stationary feeding fish such as a trout can be considered to be a "drift sampler" intercepting particles in the current, some suggestions are made about the development of a theory concerning the delivery of items of food to such a predator.
Growth and Chemical Composition of Chum (Oncorhynchus keta) and Sockeye (O.nerka) Salmon Fry Produced in Spawning Channel and Natural Environments
Authors: Vanstone W. E. , Markert J. R. , Lister D. B. , Giles M. A.
Published: April 2011

A comparison was made of the weights, lengths, weight–length relations, and chemical composition in migrating chum and sockeye fry resulting from eggs incubated and hatched in natural and artificial streams. Additionally, growth rates and rates of change in some chemical constituents were investigated in postmigrant channel- and river-hatched chum salmon confined to floating pens in sea water and in postmigrant sockeye salmon captured from their lake nursery area.There were no apparent differences in the lengths, weights, weight–length relations, or chemical composition between river- and channel-hatched chum salmon migrants. Nor was there any difference in the rates of change in length, weight, or chemical composition of these two groups of chums when confined to pens in sea water for 10 weeks after migration.There were differences in the weight–length relations, lipid content, and nitrogen content between channel- and river-hatched sockeye migrants. It is suggested, however, that these differences are due to the fact that the timing of the peaks of migration of these two groups of fish differed and that at any one time channel fry were physiologically different from river fry.Growth of the chum salmon in sea water and the sockeye in the lake was exponential and the slope of the weight–length relation, W = aLb, was approximately 3.25. During this growth period although total weight, moisture, solids, lipid, and nitrogen increased the rate of increase in moisture was less than the rates of increase in total weight or the other constituents.
Effects of Water Currents on Distribution of Walleye Larvae in Oneida Lake, New York
Authors: Houde Edward D. , Forney John L.
Published: April 2011

Distribution of walleye (Stizostedion vitreum vitreum) larvae in Oneida Lake was followed in 1960–67 from the time 200 million 1- to 3-day-old hatchery larvae were stocked until dispersal was complete 10–15 days later. The distribution of prolarvae indicated a high proportion of the population originated from stocking. Newly stocked larvae concentrated near bottom and were transported by bottom currents into the western third of the lake. Older larvae were most abundant near the surface after yolk absorption and they were transported east by surface currents generated by the predominantly westerly winds. Distribution of larvae 8–9 days after release in 1966 and 1967 was similar to the distribution predicted from water current and wind velocity data. Larvae were dispersed further east in 1967, when winds were strong, than in 1966, when wind velocity was low.
Lipids and Fatty Acids of Two Species of North Atlantic Krill (Meganyctiphanes norvegica and Thysanoëssa inermis) and Their Role in the Aquatic Food Web
Authors: Ackman R. G. , Eaton C. A. , Sipos J. C. , Hooper S. N. , Castell John D.
Published: April 2011

The fatty acid compositions of phospholipids and triglycerides from two lots of Meganyctiphanes norvegica (M. Sars), and of total lipids of two additional lots of different origin, showed characteristics commonly found in lipids of carnivorous higher animals such as herring. The fatty acids in both phospholipids and triglycerides of one sample of Thysanoëssa inermis (Krøyer), although qualitatively similar to those of the M. norvegica lipids, showed a closer quantitative relationship to phytoplankter fatty acids and suggested that this species is herbivorous. These observations are discussed in terms of biological data on the feeding habits of the animals, and their basic biochemical processes as related to overwintering or other times of food scarcity. The crustacean samples, obtained from the stomachs of fin whales captured off Nova Scotia, had 1.2–2.4% total lipid, with nonsaponifiable materials accounting for 3–5% of the lipids in M. norvegica and 10% in T. inermis. The potential utilization of these species in artificial rearing of trout or salmon is discussed.
Vital Statistics of a Population of Great Lakes Rainbow Trout (Salmo gairdneri) Characterized by an Extended Spawning Season
Authors: Dodge Douglas P. , MacCrimmon Hugh R.
Published: April 2011

Adult fish moved into Bothwell's Creek, Lake Huron, between October 29 and May 3. Run A (October 29–February 15) was composed of 640 fish, run B (February 16–May 3) of 610 fish. Run A spawned between December 29 and February 14 and left the river. Run B spawned between February 20 and April 30. Total lengths of males ranged from 31 to 80 cm, females from 21 to 90 cm. Fourteen categories of life history were identified within the population of which 99% had become smolts after 2 years of stream life. Fish of age 5 were dominant. Differences in age class structure and size of fish occurred between runs A and B. Sea lamprey scars were evident on 8.6% of fish, all over 46 cm in total length.
Benthic Infauna Communities off the Coast of Washington and in Puget Sound: Identification and Distribution of the Communities
Authors: Lie Ulf , Kelley James C.
Published: April 2011

Benthic infauna was collected at 37 stations in Puget Sound, in Juan de Fuca Strait, and off the northwestern coast of Washington during the summer of 1967, and at 18 additional stations off the southwestern coast of Washington during the summer of 1968. The crustaceans, lamellibranchs, and echinoderms were identified and counted, and the data were subjected to an analysis of affinity among stations, to Fager's recurrent group analysis, and to factor analysis for identification of the benthic communities and the groupings of benthic species in the investigated area.Trellis-diagrams of indices of affinity among the stations, based on the presence or absence of species, indicated four rather distinct groups of stations with specific geographic distributions or relations to certain sediment types. Fager's recurrent group analysis for the 36 most frequently occurring species resulted in eight groups and five species that were strongly associated with one or more of the recurrent groups. Most tests of interspecific relations among the species within the groups were not significant, and it was concluded that the analysis was only partly useful for delimiting species groups with ecological significance. The Q-mode of the factor analysis resulted in three groups of stations distributed in bands parallel to the coast, and each group of stations (community) could be recognized by its distinct sediment types or depth distribution. The R-mode of the factor analysis gave six groups of species with specific preferences of depths, sediment types, or geographic distribution. The results of the various techniques were compared, and their application in benthic synecology was discussed.