bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics and Exploitation of Lake Whitefish in Southern Georgian Bay
Authors: Cucin Daniel , Regier Henry A.
Published: April 2011

Instability of the population of Coregonus clupeaformis (Mitchill) in southern Georgian Bay from 1948 to 1964 was evidently partly due to intensive fishing.The population was discrete at least from 1956 to 1964 as determined by extensive tagging. From 1948 to 1964, estimated effective fishing effort varied 10-fold and annual yields almost 20-fold, with two cycles of abundance and scarcity. Strength of 1951–59 year-classes, defined as population size at age III, varied 40-fold. In spite of the marked instability, the population was in recent years more stable than any other whitefish population in Georgian Bay or Lake Huron.Almost all the commercial catch was made with gill nets of [Formula: see text] mesh. In 1957, fishing depended largely on age VII–IX fish; by 1964, on those of age V and VI. Apparent growth rate increased during this period: in 1957 age XII fish weighed 3.4 lb; in 1964 age VI weighed 3.7 lb. From 1959 to 1964, reproduction depended largely on males age IV+ and older and longer than 17 inches, and on females age V+ and older and longer than 18 inches.Natural mortality coefficients (exponential model) averaged 0.41 for fish of the 1948–58 year-classes beyond age III. Gillnetting was largely restricted to 2 months in late spring and two in fall. In each fishing season these gill nets took about 40% of the survivors of a year-class after it became fully vulnerable, at ages V, VI, and VII during the early 1960s.Combining growth and natural mortality rates in a biomass curve indicated that individual year-classes would provide highest yields when fished intensively at age IV, or slightly earlier than they were fished in the early 1960s. Yet the only hypothesis that might explain the continued existence of a fishable population was that relatively large parts of the habitat were either legally closed or unsuitable for fishing. Evidently the fishing was intense and increasing the effort would mean risk of a population collapse.
Comparative Summer Limnology of Inner Long Point Bay, Lake Erie, and its Major Tributary
Authors: Berst A. H. , McCrimmon H. R.
Published: April 2011

Long Point Bay, on the north shore of Lake Erie, is 28.2 square miles (7278 hectares) in area, with a maximum depth of approximately 10 ft (3.05 m). Big Creek, the major tributary, drains a watershed of 317 square miles (81,818 hectares), and discharges 4700 million cubic feet (127,000 million liters) of water into the Bay annually. Summer water temperatures in the Creek and the Bay were positively correlated with air temperatures in 1962. The water in the Bay was subject to considerable seiche action. Levels of nutrients and suspended materials were characteristically higher in the Creek than in the Bay. Gross reductions in levels of turbidity, total dissolved solids, nitrates, and phosphates occurred in the lower section of Big Creek and the adjacent area of the Bay. For example, phosphate levels of bottom samples were inversely correlated with those of water samples in lower Big Creek and its estuary. The path of Big Creek discharge through the Bay to Lake Erie was defined by an analysis of total dissolved solids and soil phosphate data.
Swimming Endurance of Some Northwest Atlantic Fishes
Authors: Beamish F. W. H.
Published: April 2011

Endurance was determined in relation to swimming speed and temperature for Atlantic cod, Gadus morhua Linnaeus, redfish, Sebastes marinus (Linnaeus), winter flounder, Pseudopleuronectes americanus (Walbaum), and to swimming speed at 8 C for longhorn sculpin, Myoxocephalus octodecimspinosus (Mitchill), sea raven, Hemitripterus americanus (Gmelin), and ocean pout, Macrozoarces americanus (Block and Schneider).In an activity chamber at a swimming speed of 4 body lengths per second (BL/sec) Atlantic cod swam for about equally long periods at 5 and 8 C, and redfish and winter flounder each about equally long at 5, 8, and 11 C. The pattern was similar for higher speeds. At 14 C winter flounder swam longer at 6 BL/sec than at the lower temperatures. For swimming speeds less than 4 BL/sec all species swam longer at the higher temperatures. At 8 C, the only temperature at which all species were tested, endurance at comparable swimming speeds was greatest for winter flounder, followed by cod, redfish, longhorn sculpin, ocean pout, and sea raven.
Occurrence of Dimethyl-β-Propiothetin in Marine Phytoplankton
Authors: Ackman R. G. , Tocher C. S. , McLachlan J.
Published: April 2011

Dimethyl-β-propiothetin has been reported from several species of freshwater and marine multicellular algae. Cultures of 14 species of unicellular marine algae were treated with cold aqueous alkali. Dimethyl sulphide was liberated from Syracosphaera carterae, Skeletonema costatum, Amphidinium carteri, Phaeodactylum tricornutum, Tetraselmis sp. and Cyclotella cryptica, and is assumed to arise from dimethyl-β-propiothetin. The amounts of alkali-labile material varied, on a wet weight basis, from 0.07 to 2.9% (as thetin salt) in different organisms. The presence of the thetin in S. carterae was confirmed by other means. The thetin, and particularly its degradation products, acrylic acid and dimethyl sulphide, may influence actual fishing operations and also affect the quality of fishery products. The metabolic and ecological significance of these materials are reviewed and discussed.
Relationship Between Size and Maturity in the Spottail Shiner, Notropis hudsonius
Authors: Peer D. L.
Published: April 2011

not available
Foetal and Postpartum Whitecoat Pelage in Phoca vitulina
Authors: Stutz Sherwood S.
Published: April 2011

not available
1α-Hydroxycorticosterone from Cartilaginous Fish: a New Adrenal Steroid in Blood
Authors: Idler D. R. , Truscott B.
Published: April 2011

not available
Reproductive Rates of Harp Seals, Pagophilus groenlandicus (Erxleben)
Authors: Sergeant D. E.
Published: April 2011

In less than a decade the mean age at sexual maturity of female harp seals of the Front, or northeastern Newfoundland population, decreased to 4 from [Formula: see text] years. Exploitation was heavy during this period and included a high proportion of seals older than 1 year. Females of the Gulf of St. Lawrence herd declined in mean age at sexual maturity over the same decade to 5 from nearly 6 years. Exploitation of this herd was lower, especially for animals older than their first year. Fertility of the adult females was likely higher in the more heavily exploited population. Published data on the White Sea population, which was reduced to low numbers, show reproduction at a lower mean age than for the present Front herd; for the Jan Mayen herd, of uncertain population status, about the same reproductive rate as the present Gulf herd. In most of the populations, samples of adult, whelped females showed the greatest number in the age-class about 1 year older than that first showing 100% of the females mature, as would be expected; however, samples from the Front herd showed dominance of an older age-class, suggesting that young adult females may to some extent segregate into separate groups. The immediate factors leading to increased reproductive rates at lower population densities were not elucidated.
Some Commercial Atlantic Herring Oils; Fatty Acid Composition
Authors: Ackman R. G. , Eaton C. A.
Published: April 2011

Twelve commercial samples of oil from Atlantic herring (Clupea harengus L.) were examined for fatty acid composition by gas–liquid chromatography. Individual fatty acid components varied widely between these oils, but an assessment of the respective totals of saturated, monounsaturated, and polyunsaturated acids from these oils and from oils of other species has led to an empirical formula giving the total per cent polyunsaturated fatty acids in marine oils as: total polyunsaturated fatty acids = 10.7 + 0.337 (iodine value oil — 100)In the Atlantic herring oils studied the average proportions of the saturated, monounsaturated, and polyunsaturated fatty acids were 20, 60, and 20%, respectively. In comparison with herring oil analyses reported from other areas the total saturated acids in the Atlantic herring oils are slightly lower, but there is general agreement that hexadecanoic acid averages about 60% of the total saturated fatty acids. Relationships which are fairly consistent among other acids and apparently not related to iodine value include the ratio of hexadecanoic acid to hexadecenoic acid plus octadecenoic acid, the ratio of C20 and C22 successor acids to C18 linoleic-type precursor acids, and the ratio of linolenic-type acids compared to immediate precursors of the same chain length. As iodine value increases the saturated acids increase slightly, and in the linolenic type acids the ratio of C20 to C18 fatty acids increases more noticeably than the ratio of C22 to C18. The ratio of C22 to C20 linolenic-type acids accordingly decreases with increasing iodine value. The ratio of total linolenic-type acids to total linoleic-type acids apparently increases with increasing iodine value. Comparisons are made with oil analyses of clupeids taken in other oceanic areas.
Ocean Migration and Distribution of Fin-Marked Coho Salmon
Authors: Allen George H.
Published: April 2011

Migration, distribution, and movement of five groups of fin-marked coho salmon of the 1950 brood planted into Puget Sound, Washington, in 1952, were followed during 1952 and 1953 by a study of 847 recoveries of marked salmon taken in sport and commercial fisheries in the Pacific Ocean, Puget Sound, and closely adjoining regions.Differences in migration, distribution, and movements of the five groups of salmon were correlated with the time, place, and method of planting.The most pronounced difference in behavior was shown by salmon receiving an extra 2 months of rearing in the hatchery as compared with other groups. This group was marked by removal of the dorsal and right ventral fins. A lag in average time of migration to points in the ocean and a tendency to migrate lesser distances while in the ocean characterized the behavior of these fish. This lag in time of migration as indicated by patterns of recovery of marked salmon from sport and commercial fisheries was confirmed by an actual lag in time of return to the point of release.In migrating from off the coast of Washington to Puget Sound, the salmon moved at an estimated rate of 5–7 nautical miles per day.
Taste Panel Assessment of Cod Fillets After Single and Double Freezing
Authors: MacCallum W. A. , Laishley E. J. , Dyer W. J. , Idler D. R.
Published: April 2011

Taste panel assessment is reported for Atlantic cod (Gadus morhua) frozen once and twice, and stored at −23 C. The fish were bled, gutted, and iced immediately after capture, and frozen as fillets or dressed fish before, during, and after rigor mortis. Dressed fish were thawed later in recirculated tap water, then processed, refrozen, and stored as fillets. The procedure was conducted three times (June 27, July 19, July 30) during the inshore trap fishery and twice (March and October) during the offshore Grand Bank fishery.For trap-caught landings, the quality of the stored fillets frozen once depended upon the season of catch; for Grand Bank cod, upon the time and place of catching. Trap fish, feeding lightly, caught in cold water in June, were of best quality, grades equalling 70 and over after 20 weeks storage. Those caught on July 30 while feeding heavily in warm water were second; the July 19 fish, obtained under nearly similar conditions, were not significantly poorer than those taken on July 30 and were still acceptable. March landings of Grand Bank fish, once frozen, scored over 70 after 20 weeks storage; October landings only 40 (borderline quality) after 30 weeks. Physiochemical and chemical assessment confirmed the poor quality of the latter.Thawing, refreezing, and storage of June trap fish longer than a few weeks resulted in poor but still acceptable samples. The stored product was soon similar in quality to samples prepared from July landings. In contrast, twice-frozen samples prepared from the March landings from the Grand Bank continued to score high, 70 after 28 weeks storage. Refrozen October samples from the Grand Bank yielded much lower scores, similar to those given the once-frozen samples of the same catch. Thus, in general, an acceptable or better twice-frozen product was obtained by starting with material well handled and quickly chilled, from either the inshore or offshore fishery.
Some Haematological Responses to Sublethal Thermal Shock in the Goldfish, Carassius auratus L.
Authors: Falkner Neil Ward , Houston A. H.
Published: April 2011

Red cell numbers and haematocrit values were notable principally for their constancy during a 10-day experimental period following the exposure of goldfish acclimated to 20 C to an abrupt increase of 10 C in environmental temperature. Mean erythrocytic volume underwent a transient decrease while total blood iron (and presumably haemoglobin) and mean erythrocytic iron content fell slightly during the latter portion of the period of observation. Goldfish maintained at 5 C were typically characterized by two haemoglobin polymorphs, a third fraction being commonly found in animals acclimated at 12, 20, and 30 C. The observations are discussed in relation to the respiratory acclimation of this species to increases in environmental temperature.
Oxygen Dissociation Curves of the Blood of Atlantic Salmon (Salmo salar) Acclimated to Summer and Winter Temperatures
Authors: Black Edgar C. , Tucker Harold H. , Kirkpatrick Donald
Published: April 2011

Oxygen dissociation curves were constructed at three tensions of carbon dioxide, viz: 0–1 mm Hg, 10 mm Hg, and 40 mm Hg; and at five temperatures: 0, 5, 15, 20, and 25 C. Carbon dioxide dissociation curves were constructed at 5 C only. Gas tensions in mixed venous blood were determined for four salmon at 5 C. Oxygen dissociation curves at three temperatures were carried out for fish acclimated to summer and winter conditions.The physiological function of the blood of Atlantic salmon (Salmo salar) is well adapted for the range of temperatures encountered. As is the case for other salmonids, the adverse effect of low temperature is opposed by an increased sensitivity of the blood to carbon dioxide. No influence of acclimation was observed for the effect of carbon dioxide on the equilibrium between oxygen and hemoglobin.
Steroid Transformations by Corpuscles of Stannius of the Atlantic Cod (Gadus morhua L.)
Authors: Idler D. R. , Freeman H. C.
Published: April 2011

Corpuscles of Stannius tissue of Atlantic cod (Gadus morhua L.) transformed [4-14C] pregnenolone to progesterone and [4-14C] progesterone to 11-desoxycorticosterone in vitro. These results establish the presence of 3β-hydroxysteroid dehydrogenase, Δ5-3-ketoisomerase and 21-hydroxylase. Transformation of the 14C-steroid precursors to several as yet unidentified substances also occurred.
A "Red Water" Bloom of Gonyaulax acatenella in the Strait of Georgia and its Relation to Paralytic Shellfish Toxicity
Authors: Prakash A. , Taylor F. J. R.
Published: April 2011

not available
Rare Marine Fishes from British Columbia with First Records of Silver Perch, Hyperprosopon ellipticum, and Shanny, Leptoclinus maculatus
Authors: Peden Alex E.
Published: April 2011

not available
Combined Effect of Starvation and Severe Exercise on Glycogen Metabolism of Rainbow Trout,Salmo gairdneri
Authors: Black Edgar C. , Bosomworth N. J. , Docherty Georgina K.
Published: April 2011

not available
Tolerance Levels of Cod (Gadus morhua) to Low Salinity
Authors: Odense Paul , Bordeleau Andre , Guilbault Raymond
Published: April 2011

not available
Response of Rainbow Trout (Salmo gairdneri) to Antigens of Aeromonas hydrophila
Authors: Post George
Published: April 2011

Rainbow trout (Salmo gairdneri) produced antibodies specific for Aeromonas hydrophila. Two parenteral routes yielded no measurable difference in rate of antibody synthesis. Method of bacterin suspension indicated adjuvant suspension was superior in maintenance of humoral antibody and challenge protection when compared to saline suspension of the organism.Antibody synthesis from adjuvant-suspended bacterin lagged approximately 30 days behind the rate of synthesis by fish receiving saline suspended bacteria. The highest measurable antibody titer reached by an individual was 1:64. Individuals receiving saline suspended bacterin showed evidence of loss of titer approximately 2 months after the last antigen inoculation. Definite decrease in titer was noted 5 months after the last antigen inoculation and the return to a probable nonimmune class by approximately one-half of the individuals 7 months after the last inoculation. All individuals receiving adjuvant-suspended bacterin remained in the probable immune class for as long as 6 months following the last bacterin inoculation, but only approximately one-half of the individuals remained in the probable immune class 7 months postinoculation.All fish receiving a weighed quantity of killed A. hydrophila orally each day for 9 consecutive months showed presence of humoral A. hydrophila antibody. This immunization procedure produced 50% of the individuals with humoral antibody titers considered to be in the probable immune class.Fish receiving no immunization remained with negative antibody titers throughout the experimental period.Definite protection was given fish which had been immunized by parenteral inoculation.Similar protection was given after immunization by either intramuscular or intraperitoneal routes. Fish receiving either saline or adjuvant-suspended bacterin parenterally showed analogous protection when challenged by the specific bacteria. Fish receiving oral bacterin received questionable protection against parenteral challenge of the specific organism.Phagocytosis was found to occur to a greater extent in immunized rainbow trout than in nonimmunized rainbow trout. An average phagocytic index of parenterally immunized rainbow trout was 1.08. Nonimmunized rainbow trout of the same age and egg source had an average phagocytic index of 0.30. The opsonic index was 3.6.
Muscular Fatigue and Mortality in Haddock, Melanogrammus aeglefinus, caught by Otter Trawl
Authors: Beamish F. W. H.
Published: April 2011

Haddock were subjected to strenuous muscular exertion in capture by otter trawl. In each of seven tows, blood lactic acid followed a similar pattern with peak levels between 90 and 240 min after capture. Generally, in surviving fish, lactic acid subsided to preexercise levels within 12 hr after capture. Tagging fish immediately after capture had no demonstrable influence on lactic acid level during recovery. Among the seven tows, mortality associated with fatigue ranged from 0 to 27%. Mortality estimates were made for an additional nine tows. Where mortality was attributable to fatigue, lactic acid varied between 100 and 220 mg/100 ml, with a mean of 150 mg/100 ml. Percentage mortality ranged between 7 and 78.
Consumption of Food by the Resident Population of Pike, Esox lucius, in Lake Windermere
Authors: Johnson L.
Published: April 2011

The annual consumption of food, the annual production, and the yield of pike in Windermere are determined from equations devised by Beverton and Holt (1957). The determination of the various population parameters is described and these are combined with the results obtained from the experimental determination of food consumption to provide numerical solutions. Prior to the start of heavy exploitation in 1944 the biomass is estimated to have been 8182 kg with an annual consumption of 22,124 kg. After 10 years of fishing the biomass has been reduced to 4349 kg with a consumption of 16,563 kg; this represents a 47% reduction in biomass for a 25% reduction in consumption. These results are discussed in terms of cropping the annual production of the lake.
Morphology of the Digestive Tract of the Cod, Gadus morhua
Authors: Bishop C. , Odense P. H.
Published: April 2011

The morphology of the digestive tract of the cod (Gadus morhua) was studied from dissections and histological sections.The stomach of the cod is between the siphonal and caecal types described by Grasse; and has well-developed glands compared to other teleosts. Glands are also present in the numerous pyloric caeca and intestine, and it appears that the constant replacement of the epithelial cells occurs from these. "Pear-shaped" cells which could be enzyme-producing are present in both the epithelium and glands of the ileum and pyloric caeca.The pancreas of the cod is diffuse. Islets of Langerhans were found in the pancreatic tissue along the bile duct as well as at the apex of the gall bladder as described by McCormick and between the pyloric caeca as described by Rennie.
Adjustment of Buoyancy in Atlantic Salmon Parr in Relation to Changing Water Velocity
Authors: Neave Nancy M. , Dilworth Carole L. , Eales J. G. , Saunders R. L.
Published: April 2011

not available
Nutrient and Energy Cycles in an Estuarine Oyster Area
Authors: Uyeno Fukuzo
Published: April 2011

The nutrient circulation and microbial abundance of oyster-producing waters in the Malpeque Bay area, Prince Edward Island, were followed at two stations through an open season, and the efficiency of carbon assimilation and dissimilation was estimated. Part of the organic fall-out evidently entered the water again in the spring as nutrient salts, but a certain portion was not returned and this represented a net loss from the ecosystem. The nutrient circulation at a station located in a saltwater pond was more efficient than at a station located in a river estuary. In the pond, mineralization was 31% of primary production, largely by mud bacteria; in the estuary it was 17%, about equally by mud and water organisms.
Studies on Chemical Composition of American Crayfish (Orconectes limosus) Meat as Related to its Nutritive Value
Authors: Dabrowski Teofil , Kolakowski Edward , Wawreszuk Helena , Choroszucha Czeslawa
Published: April 2011

The chemical composition of male and female meat of the American crayfish (Orconectes limosus Raf.) was determined and the relationship between the weight, and total length and the yield of edible meat of the crayfish was established.The American crayfish meat was found to contain on the average for both sexes 80.9% water and 2.75% total nitrogen of which 83% accounts for protein nitrogen.In the protein composition myosin constitutes 32.9%, myogen 30.1%, residual intracellular protein 26.4%, and protein of stroma 10.5% of the true protein. The amine nitrogen content of both sexes averages 202.1 mg/100 g, which accounts for 42.6% of nonprotein nitrogen.The American crayfish contains more phosphorus than do fishes. Its meat averages 296.4 mg/100 g P of which the acid insoluble fraction constitutes 36.1%, inorganic phosphorus 35.5%, and ester phosphorus 28.4%. Males contained more total, acid-insoluble, and ester phosphorus and less inorganic phosphorus than did females.The amino acid composition of free amino acid fraction, protein, and acid hydrolyzate prepared from the equal quantities of the male and female water–alcohol meat extracts were also determined. The crayfish amino acid composition resembles that, of fishes with certain distinctive features.
Pugheadedness in Perch, Perca flavescens, and Pike, Esox lucius, of Heming Lake, Manitoba
Authors: Lawler G. H.
Published: April 2011

not available
Nucleotide Degradation and Quality in Ordinary and Red Muscle of Iced and Frozen Swordfish (Xiphias gladius)
Authors: Dyer W. J. , Fraser Doris I. , Lohnes Dianne P.
Published: April 2011

In iced dressed swordfish, inosine monophosphate, initially the predominant nucleotide (5.2 μmole/g), was dephosphorylated to inosine during 19 days storage. Hypoxanthine increased very slowly to about 1 μmole/g while quality (taste panel) showed no significant decrease to 15 days but was near borderline at 19 days. These changes occurred more slowly than in cod and related species. The sequence of nucleotide changes occurred much earlier in the red muscle. Rapid freezing and storage at −26 C for 4–5 months inhibited nucleotide enzymic activity, and quality remained unchanged. Slow freezing and storage for 1 week at −4 C significantly reduced quality to borderline or unacceptable levels, but only slightly affected the nucleotide degradation, indicating that other factors were responsible for the loss in quality. Dephosphorylation and hypoxanthine accumulation continued during further storage at −4 C. The levels of hypoxanthine reached during 19 days iced storage or 4–5 months frozen storage were not sufficiently high to impart bitter flavors, except possibly in the red muscle. A simple measure of inosine (+ hypoxanthine) may be useful as a quality test; a supplementary hypoxanthine test could be used to confirm spoilage.
Mouth and Body Form Relative to Feeding Ecology in the Fish Fauna of a Small Lake, Lake Opinicon, Ontario
Authors: Keast Allen , Webb Deirdre
Published: April 2011

In 14 cohabiting fish species in a small freshwater lake, mouth and body structures combine with food specializations and habitat preferences to greatly restrict interspecific competition within the fauna.The species differ quantitatively in a large number of structures and, individually and in combination, these are clearly adapted for distinctive roles. The mouth is particularly plastic, varying in position, in aperture width, and in overall form, with structures as diverse as a scoop, a beak, and a tube being found. Six basic body types occur and these, combined with varying fin morphologies, result in a range of distinctive forms, including the following. Micropterus salmoides, with a compressed fusiform body and a wide mouth, is a strong-swimming, widely ranging piscivore. Notemigonus crysopterus, with a long, slender caudal peduncle, subfalcate pectoral fins, and a deeply forked caudal fin, has great maneuverability that permits it to catch individual zooplankters. Lepomis macrochirus is a "sedentary," gibbose-bodied water-hanger. Umbra limi has a stubby, cylindrical body that favours life in dense vegetation. Labidesthes sicculus, with an almost straight dorsal line to the body, a low dorsal fin, and a beak-like snout with tweezer-like teeth, is modified for surface feeding and leaping out of the water. Ictalurus nebulosus has chemotactile barbels that favour bottom feeding and paired fins that function partly as hydrofoils, keeping the body inclined downwards as the mouth sweeps the bottom.The structural specializations give their owners a decided ecological advantage in certain situations. Only a few species, however, are limited by them to restricted ways of life. In most cases, a considerable measure of feeding flexibility is retained, presumably important for survival in cold temperate lakes.
Food and Feeding Apparatus of Two Pelagic Shrimps
Authors: Renfro William C. , Pearcy William G.
Published: April 2011

not available
Scale Formation as Related to Growth and Development of Young Carp, Cyprinus carpio L.
Authors: McCrimmon Hugh R. , Swee U. Boon
Published: April 2011

Scales began to form on the body of young carp at 16–18 mm in total length. Scales first appeared anteriorly. The first row formed immediately below the lateral line, except for the posterior four or five scales being typically on the line. Later rows formed in succession above and below the first, each beginning anteriorly. Young carp acquired the typical structure and form of the adult fish by 21 mm. Squamation was completed on fish of 22–26 mm. The development of mouth parts, swim bladder, fins, and body scales appeared to be a function of length.
A Hatchery Release Tank for Pink Salmon Fry With Notes on Behavior of the Fry in the Tank and After Release
Authors: Coburn A. , McCart P.
Published: April 2011

A hatchery release tank was designed which permitted the voluntary release of pink salmon (Oncorhynchus gorbuscha) fry. Fry release was stimulated by rising temperatures and increasing turbidity. Because even relatively immature fry left the tank under these conditions, fry were released only between 0800 and 1000 hr, when both temperature and turbidity were low. After entering the stream, hatchery-produced fry appeared to behave normally. They buried themselves during daytime and, within a few days, moved downstream during the night.
The Thermal Regime of South Bay, Manitoulin Island
Authors: McCombie A. M.
Published: April 2011

The thermal regime of South Bay is described from records collected from 1953 to 1962 with thermometers, thermographs, and bathythermographs, the last being cast at 11 stations along the bay and one in Lake Huron. Warming begins in April and thermal stratification is established in June. Shallow areas warm more rapidly than deep in the spring and cool more quickly in autumn. The boundary between the epilimnion and the thermocline becomes sharper as summer advances but the transition from thermocline to hypolimnion remains gradual. The average seasonal trend of surface temperatures is a sine function with a maximum of 66 F in mid August and a minimum of 34 F in late March, though values outside this range occur frequently. At 180 ft the maximum of 47 F is attained in November. At the lake and outermost bay stations there is a temperature slump in June and July which may be due to an upwelling in the lake. Evidence of an exchange of water between the lake and bay is seen in vertical temperature sections and water movements Variations in epilimnial temperatures are correlated with those of the air temperature, but variations in epilimnial and hypolimnial temperatures appear to be unrelated. Finally, literature describing the influence of temperature on the year class strength of smallmouth bass, the distribution of lake trout, the growth of yellow perch, and the life history of Pontoporeia in South Bay is reviewed.
Effects of Water and Dielectric Thawing Processes on Shelf Life of Double-Frozen Cod and Redfish
Authors: MacCallum W. A. , Chalker Dorothy A. , Dyer W. J. , Idler D. R.
Published: April 2011

Analytical taste panel results showed that immersion-thawing in tap water at two different temperatures (7.2 and 15.5 C) and dielectric thawing (at 38 Mc/s) had similar effects on the cold-storage life (at −23 C) of processed, refrozen fillets of cod (Gadus morhua) and of redfish (Sebastes marinus mentella) (water thawing at 15.5 C only).Refrozen fillets from Grand Bank cod, captured in March, iced 4 days and frozen, water-thawed, and reprocessed as above, though not quite as good as once-frozen controls, were still of good quality after 35 weeks storage.Lightly feeding June trap cod, captured in cool (4 C) inshore water, iced, and frozen before and during rigor mortis, then water-thawed and refrozen, were still acceptable after 28 weeks storage, but were considerably poorer than samples frozen once. Quality was similar at both thawing, temperatures (7.2 and 15.5 C) and both conditions of rigor at first freezing.Heavily feeding July trap cod, captured in warmer (7–9 C) inshore water, similarly handled and similarly processed and refrozen following thawing in water at 15.5 C or dielectrically, were of just acceptable quality up to 32 weeks in storage and were similar to samples frozen once.Grand Bank redfish, similarly frozen before and during rigor and later processed and refrozen, maintained very acceptable quality up to 28–34 weeks with both thawing procedures and state of rigor at freezing and were equal to samples frozen once. Thiobarbituric acid values increased on storage.
Fawn Cusk-eel, Lepophidium cervinum, in the Northwest Atlantic
Authors: McKenzie R. A.
Published: April 2011

not available
Glycerylphosphorylcholine and Related Compounds in Rainbow Trout Muscle Stored at −4 C
Authors: Jonas R. E. E. , Bilinski E.
Published: April 2011

Glycerylphosphorylcholine in rainbow trout (Salmo gairdneri) muscle stored at −4 C showed an increase from 36 μmoles/100 g in fresh muscle to 46 μmoles/100 g after 2 weeks. During longer periods of storage an approximately threefold increase in concentration took place, reaching 123 and 105 μmoles/100 g muscle after 9 and 17 weeks. Liberation of free choline was found to take place after 6 weeks of storage. There was very little change in the concentration of choline after 6 weeks storage when the value was approximately 100 μmoles/100 g. The release of free fatty acid during cold storage showed a general trend, which was similar to the formation of glycerylphosphorylcholine, but quantitatively the changes were more pronounced. Free fatty acids amounted to 45 μmoles/100 g in fresh muscle and rose to a plateau of approximately 1200 μmoles/100 g after 9 weeks of storage. The results are discussed in relation to the enzymic activity present in fish muscle.
Behaviour and Ecology of Sockeye Salmon Fry in the Babine River
Authors: McCart P.
Published: April 2011

In the Upper and Lower Babine rivers the fry of sockeye salmon (Oncorhynchus nerka) emerge and move downstream, predominately at night, before reaching low-velocity areas along the stream margins. After a period of days or weeks these fry migrate upstream, close inshore, during the day. The diel pattern of upstream movement appears to be bimodal. The seasonal periodicities of both downstream and upstream movement are related to water temperatures.Upstream migrants were larger than downstream migrants in the Upper Babine River but not in the Lower Babine River. Upper River upstream migrants were similar in length to Lower River upstream migrants during 1964 but not in 1965. In both years Upper River fry weighed proportionately more than Lower River fry, and in both rivers 1964 fry weighed proportionately less than 1965 fry. Some possible explanations of these observations are discussed.Early in the season, fry tend to disperse alongshore after entering the lake. Later they leave these inshore areas and become entirely pelagic.The principal foods of fry both in the river and in the lake were copepod and cladoceran plankters.Both fish and birds were found to be preying on sockeye salmon fry. Fry appear to be more vulnerable to predation in the river than in the lake.The upstream movement of fry in the Babine River does not appear to differ appreciably from upstream movements in other areas. A comparison of fry movements in the Babine River and the Fulton River, where fry move only downstream, suggests that the differences in behaviour are genetically rather than environmentally induced.It is suggested that, because of high mortalities in the prepelagic period, upstream-migrant populations will only develop where the environment of both the river and the rearing lake are especially favourable.
Fatty Acid Composition of the Decapod Shrimp,Pandalus borealis, in Relation to that of the Euphausid,Meganyctiphanes norvegica
Authors: Ackman R. G. , Eaton C. A.
Published: April 2011

not available
The Significance of Ventral Bioluminescenee in Fishes
Authors: McAllister D. E.
Published: April 2011

The positions of luminous organs and tissues are documented for all known bioluminescent families of fishes. The majority of families, species, and individuals possess photophores only or mainly on the ventral half (as opposed to the dorsal half) of the body. The position and in some cases also the photophore structure tend to direct the emitted light downwards. Review of the previously suggested functions of luminescence and a new one (proposing light organs may function in the spacing out of midwater fish in the absence of marks for fixing territories) suggests that these functions are not related to the ventral predominance of luminescence. Photophores functioning as lures for prey and as headlights do not appear to follow the general tendency for ventral positioning of bioluminescence.Study of the two previously proposed theories on ventral predominance of luminescence, the reflector theory and the "counter-shading" or disruptive illumination theory, shows that there are some cases which these theories do not explain; these two theories apply only during the day. A third theory is developed which suggests that the larger numbers of predators in upper waters would select for fishes with ventrally directed nocturnal luminescence as this would subject them to less predation. Fishes possess photophores for a number of reasons, but they are placed ventrally because this results in decreased predation. Some counter-strategies are discussed, showing how fishes have coped with certain problems created by bioluminescence.
Feeding and Migration Patterns of the Pink Shrimp, Pandalus montagui, in the Estuary of the River Crouch, Essex, England
Authors: Warren P. J. , Sheldon R. W.
Published: April 2011

Feeding of the pink shrimp, Pandalus montagui, took place mainly in daylight at low slack water. There was relatively little feeding at low slack water at night, and almost no feeding at other times. Sand grains were ingested with the food and it was possible to identify areas where feeding could have occurred by comparing grain-size distributions of material from the stomachs with those of the bottom deposits. It was possible to show, by fishing in selected areas and by considering patterns of tidal flow, that feeding was restricted to a small area near the mouth of the River Crouch, and that P. montagui migrated from this area with the flood tide and returned to it on the ebb.
Postmortem Physicochemical Changes in Unfrozen Newfoundland Trap-Caught Cod
Authors: MacCallum W. A. , Jaffray June I. , Churchill D. N. , Idler D. R. , Odense P. H.
Published: April 2011

Cod (Gadus morhua) caught in traps along the shores of Newfoundland are shown to be high in muscle glycogen, reaching a peak in late July and, unfrozen, reach a lower pH post-mortem than do cod caught in other Newfoundland fishing operations. Seawater temperature, muscle glycogen at death, and free drip developed in the fillets were minimal in June and maximal in late July. Fillets of these latter fish, after freezing during rigor, were of significantly poorer texture that those prepared earlier and later in the season.Fish which were not iced as soon as caught entered rigor mortis within 1 or 2 hr and although iced in the interim, were out of rigor in 24–36 hr. Fish iced at the trap were in full rigor 8–15 hr later; although rigor did not disappear completely for 70–90 hr, the fish could be filleted, by hand, in 24 hr.Generally, there were small weight losses in whole eviscerated fish not iced until several hours after capture but this weight was regained completely after 34 hr.Whole, eviscerated fish iced at capture developed less drip in the fillets than fish permitted to warm before icing. In fillets of fish in all stages of rigor there was a consistent trend for drip to increase with decreasing pH at filleting. The pH levels in turn were dependent on season of catch and on glycolysis after killing. In late midseason (August 2) catches, muscle glycogen appeared to be directly responsible for pH drop whereas in fish captured earlier, feed, physiological condition, and seawater temperature appeared to be the principal catalysts of pH change. Fillets prepared during rigor (August catches) showed no further drop in pH from that of the parent, iced material and developed 2–3% free drip in 24 hr; those processed before or after rigor mortis showed a further drop in pH from that occurring in the whole fish, and drip developed was much greater than in the samples filleted during rigor. Because considerable variability was noted in the rate of rigor development in any one catch, the particular state of rigor at filleting was found to correlate better with the amount of free drip in the fillets than was postmortem, age. The development and resolution of rigor in fillets was accompanied by considerable reduction in the solubility of the proteins (in 0.6 M NaCl solution), significantly more than in whole fish.If, for production reasons, trap fish must proceed into rigor before freezing, they should be chilled and stored in the whole, eviscerated state rather than as fillets.
The Shrinkage Factor in Measurements of Groundfish
Authors: Forrester C. R.
Published: April 2011

not available
Fish Losses After Forest Sprayings with Insecticides in New Brunswick, 1952–62, as Shown by Caged Specimens and other Observations
Authors: Kerswill C. J. , Edwards H. E.
Published: April 2011

The survival of young Atlantic salmon and eastern brook trout, held in cages and free-living, was observed in New Brunswick streams inside and outside forested areas sprayed operationally and experimentally from aircraft with DDT and other insecticides for budworm control. DDT-in-oil in a single application at [Formula: see text] caused heavy loss of underyearling salmon and parr within 3 weeks. DDT-in-oil at [Formula: see text] had no apparent short-term effects on salmon parr, but killed many underyearlings; two applications 10 days apart were about as harmful as a single application at [Formula: see text]. DDD at [Formula: see text] and [Formula: see text], and malathion at [Formula: see text], were no more harmful to young salmon than DDT at [Formula: see text]. Replacing Stearman airplanes with larger aircraft in operational spraying and associated changes in spraying procedure sometimes caused heavy fish losses even for single applications of DDT at [Formula: see text]. Experimental spraying of phosphamidon-in-water at 1 lb/acre had no apparent harmful effects on young salmon and trout.Observations at a counting fence across the Northwest Miramichi 12 miles below the lower boundary of the forested area sprayed with DDT at [Formula: see text] in 1954 showed extensive killing of suckers and cyprinids; also, the numbers of these species moving through the fence were abnormally low for several years after spraying.Wild young salmon were found dead in streams when autumn water temperatures approached freezing after June sprayings of watersheds with DDT.
Effects on Wild Young Salmon of Spraying DDT over New Brunswick Forests
Authors: Elson P. F.
Published: April 2011

When DDT-in-oil was sprayed over large tracts of New Brunswick forest some of the spray got into drainage systems lying in the spray zones. As a result, many young salmon were killed and stocks were endangered.Most New Brunswick salmon spend 3 years in rivers before migrating to sea as smolts. The young fish can conveniently be divided into three size-groups, which are roughly comparable to each year of age. The groups are: underyearlings, small parr (over 1 year old but 10 cm and under from tip of snout to tip of extended tail fin), and large parr.Wild young salmon in unsprayed and sprayed streams were assessed for numbers in each size-group, abundance being expressed as population index = average number per 100 yards2 of stream bottom.DDT at[Formula: see text]. After such spraying young salmon of all size-groups were found in noticeably low numbers as compared with unsprayed situations. Underyearlings were only 2–10% as abundant (index reduced from 24 in places not affected by spray to less than 1 in most sprayed places), small parr only 30% (index reduced from 20 to 6), and large parr only 50% (index reduced from 12 to 6) as abundant.DDT at[Formula: see text]. After spraying at this dosage underyearlings were only about 50% as abundant as with no spraying; small parr were about 80% as abundant and large parr were affected hardly at all.DDT at[Formula: see text]applied twice. This was followed by low numbers of underyearlings, similar to those observed with a single application at [Formula: see text]. No equivalent data for parr are available but other information indicates effects similar to a single spraying with [Formula: see text].Downstream transport of the DDT-in-oil mixture was an important factor in extending the, harmful effects 30 or more miles below spray zones.Delayed mortality followed 4 to 6 months after the early mortality described above. It was associated with the onset of winter cold. It may have removed a large proportion of parr which survived early mortality but quantitative measurements of this factor were not made on wild populations.Reductions in numbers of young salmon were followed by declines in numbers of adults taken in fisheries and returning as spawners.With no spraying in subsequent years, promptness of recovery of young salmon populations depended primarily on abundance of parent stock.
Echinoderms Collected from a Drifting Ice Island off the East Greenland Coast, with Comments on Their Distribution in Adjacent Waters
Authors: Stendell Rey
Published: April 2011

A collection of 127 echinoderms was made from the ice island Arlis II as it drifted southward along the east coast of Greenland. Sixteen species are represented: 2 crinoids, 4 asteroids, 8 ophiuroids, 1 echinoid, and 1 holothurian. Distributions of the animals are discussed in relation to their occurrence in Greenland and adjacent waters. Of the species collected 14 are characteristic of the east Greenland marine fauna; two are characteristic of the basin floor of the northern North Atlantic and are not commonly found in east Greenland coastal waters, and two have been recorded from both regions.
Chemical Features of the Subarctic Boundary Near 170°W
Authors: Park Kilho
Published: April 2011

During the Yaloc 66 cruise of R/V Yaquina, the vertical distribution of nutrients, pH alkalinity, apparent oxygen utilization, preformed phosphate, preformed nitrate, and specific alkalinity across the subarctic boundary near 170°W were studied. In addition to use of salinity to identify the subarctic boundary, the surface distributions of nutrients, pH, and preformed nutrients were found to be useful. Both the density-apparent oxygen utilization relationships and the specific alkalinity pattern indicated upward divergence of subsurface water having salinity greater than 34.0‰ on the north side of the boundary. A high specific alkalinity of about 0.129 immediately north of the boundary was probably due to the transport of upwardly diverged water having high specific alkalinity to near the boundary. Values for preformed phosphate and preformed nitrate gave supporting evidence that the origin of the salinity-minimum water located south of the boundary is in the subarctic region.
Age and Growth of American Plaice (Hippoglossoides platessoides) in the Newfoundland Area of the Northwest Atlantic
Authors: Pitt T. K.
Published: April 2011

Growth curves of American plaice (Hippoglossoides platessoides Fabricius) from the Grand and St. Pierre banks and the areas east of Newfoundland are presented. Ages were determined using otoliths from random samples collected by research vessels in the spring and summer during 1957–63.For the localities sampled, American plaice on the southern half of the Grand Bank are the largest and the St. Mary's Bay population the smallest at comparable ages. A positive association was found between the sizes at ages 5 and 15 for the various localities and the probable bottom temperatures.Samples of otoliths from St. Mary's Bay indicated that the greatest growth occurs during the May–November period.Year-class dominance was noted for St. Mary's Bay, but not for other areas.