bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial Heterogeneity of Phytoplankton in a Near-Shore Environment
Authors: Platt Trevor , Dickie Lloyd M. , Trites Ronald W.
Published: April 2011

An analysis of variance model for phytoplankton distribution is described, which allows the partition of the variance of chlorophyll observations into effects due to differences between stations, to differences between replicate samples at the same station, and to handling and analytical error. When the model was applied to observations of chlorophyll made in St. Margaret's Bay, N.S., it was found that, on the average, the variance between replicate samples on the same station was of the same magnitude as the analytical error variance. Significant differences were revealed between stations even at densities as high as 10 stations per 0.0625 sq miles. As the sampling area was increased (but the number of stations kept constant), the between-station variance rose rapidly, to a density of 10 stations per sq mile, after which it remained relatively constant. The maximum value of the between-station component of the variance was about 10 times the average for the between-replicate component. Heterogeneity of plankton distribution gave rise to coefficients of variation (logarithmic) up to 70% for single observations of chlorophyll concentration, for which the analytical technique has a precision of better than 10%.Analysis of chlorophyll samples taken at closely spaced stations (0.1 miles apart) along an 8-mile transect revealed considerable variability in distribution. Autocorrelation analysis of the data showed the presence of plankton patches 0.5–1.5 miles in diameter. Coherence analysis provided some evidence for correlation between the distribution of chlorophyll and of temperature and salinity. The dominant frequency in coherence spectra was −3 cycles/mile. Comparison of the autocorrelation function for chlorophyll with those for temperature and salinity indicated the influence of both deterministic and random processes on the chlorophyll distribution.Measurements taken at nine stations during the course of a plankton bloom showed that although there were differences between the stations, the time variation in chlorophyll concentration followed broadly the same course at all the stations. The variation between stations in total quantity of chlorophyll in the water column was small enough to indicate that measurements taken at a single station would be quite adequate to study major seasonal trends.
Keeping Time of Frozen Redfish (Sebastes marinus mentella) Fillets in Relation to Handling of the Raw Material and Storage Temperatures after Processing and Freezing
Authors: Lauder J. T. , MacCallum W. A. , Idler D. R.
Published: April 2011

The effect of various periods of prefreezing storage for iced, whole redfish (Sebastes marinus mentella) on the frozen-storage keeping times (at −23 C) of the fillets and the effect of various periods of fillet storage at temperatures equal to and higher than −23 C are reported. The fish were caught on the Grand Bank and on Banquereau in May and June. Assessment was by taste panel with chemical tests for protein solubility, rancidity, and pH made for purposes of comparison.Fish iced 2 days, then processed and frozen, were of acceptable quality for 83–94 weeks; those iced for 12 days, then filleted and frozen, had a storage life to unacceptability of 51 weeks. Samples processed and frozen after 4 days in ice and subjected to variation in temperature (−23 C; −12 C) during initial frozen storage, then stored at a final temperature of −18 C, as in transportation aboard a refrigerated vessel and in cold storages used in the marketing chain, had initial quality characteristics similar to fish iced for 12 days (then processed and frozen) but had a shorter storage life to unacceptability, 44 weeks. Fish iced 15 days were unacceptable for freezing.
Analysis of Ram Ventilation of Fish Gills with Application to Skipjack Tuna (Katsuwonus pelamis)
Authors: Brown Clinton E. , Muir Barry S.
Published: April 2011

Some species of fish use "ram ventilation" to pass water over the gills while swimming. Hydrodynamic analysis provides estimates of the pressure losses as the water passes through the gill spaces, and of the resistance force that must be overcome by the swimming muscles. For a 44-cm skipjack tuna (Katsuwonus pelamis), swimming at its basal speed of 66 cm/sec, the gill resistance is estimated to be 1090 dynes or 7% of the total swimming resistance. If oxygen consumption doubles, gill resistance increases to 27% of the total. The energetic cost of respiration lies between 1 and 3% of the total metabolism at basal swimming speed.
Formation of Dimethylamine in Stored Frozen Sea Fish
Authors: Castell C. H. , Neal Wanda , Smith Barbara
Published: April 2011

In cod fillets undergoing deterioration during frozen storage, the dimethylamine content increases (and not the trimethylamine content as previously reported by us). There was no evidence to show an accumulation of dimethylamine in the muscle of frozen scallops, lobster, or shrimp that were purposely held at relatively high storage temperatures. It is suggested that for fish of the family Gadidae dimethylamine might be used as a measure of "frozen-storage deterioration" in much the same way as trimethylamine has been used as a measure of microbial spoilage in the unfrozen fish.
Effect of Temperature on the Rate of Gastric Digestion in Finger ling Sockeye Salmon, Oncorhynchus nerka
Authors: Brett J. R. , Higgs D. A.
Published: April 2011

By means of serial slaughter the rate of gastric digestion in yearling sockeye salmon (30–40 g) was studied at approximately 3, 5, 10, 15, 20, and 23 C, after satiation feeding on Abernathy pellets. Subsequently the ash-free dry weight of the stomach contents was determined and expressed as a fraction of the dry weight of the fish. At any one temperature, rate of digestion appeared to be proportional to the mass of food remaining in the stomach (exponential decline). The time for complete digestion decreased from 147 hr at 3 C to 18 hr at 23 C. The time for one-half of a sample of fish to exhibit empty stomachs corresponded closely to that for a mean state of 96% gastric digestion, providing a simple means for determining rate of digestion.
Survey of Rockfishes, Especially Pacific Ocean Perch, in the Northeast Pacific Ocean, 1963–66
Authors: Westrheim S. J.
Published: April 2011

During 1963–66, a trawl and echo-sounder survey was conducted in the northeast Pacific Ocean to investigate the distribution and abundance of rockfish (Scorpaenidae) species, particularly Pacific ocean perch (Sebastodes alutus), inhabiting the outer continental shelf and upper continental slope from Cape Blanco, Oregon, to Unalaska Island, Alaska. Rockfish predominated in most trawl catches. Among areas, numbers of rockfish species declined northward, from 19–21 in the Oregon–Vancouver Island region to 5 off Unalaska Island. Within areas, maximum numbers of species were caught at intermediate depths — usually 80–139 fath (146–254 m). With rare exceptions, Pacific ocean perch was the predominant rockfish species in the trawl catches throughout the study area, although its relative abundance declined from north to south.Within areas, ocean perch catch rates were usually maximal at intermediate depths — 120–139 fath (220–254 m) in summer and substantially deeper in winter. Juvenile fish usually occupied shallower depths than adults, but were often in the company of large adults. Among areas, summer catch rates were relatively high off southwest Vancouver Island and southeastern Alaska and in the western Gulf of Alaska. Off Vancouver Island, summer catch rates were higher than winter catch rates, particularly for large adults of both sexes. Echo-sounder records indicated schools were frequently unavailable to the on-bottom trawl used in this survey.Ocean perch in the northeast Pacific Ocean were categorized, tentatively, into B.C.- and Gulf-types, whose mutual boundary is Dixon Entrance. Separation was based on differential size distributions and year-class strengths.Survival rates among year-classes were evidently quite variable, particularly for the Gulf stock west of Cape Spencer.Qualitatively, ocean perch abundance generally increased from south to north in the study area.Bottom-water temperatures varied inversely with depth and latitude. Among areas, temperature range at depths of maximal ocean perch catch rate was 4.5–7.7 C, but in high-abundance areas the temperatures did not exceed 6.0 C. Seasonally, temperature at depths of maximal catch rate varied approximately 1.5 C.
Metazoan Parasites of Salmonids and Coregonids from the Avalon Peninsula, Newfoundland
Authors: Threlfall William , Hanek George
Published: April 2011

Sixty-seven salmonids and coregonids (32 Salvelinus fontinalis, 3 Salmo salar, 22 Salmo trutta, 10 Coregonus clupeaformis), caught at various locations on the Avalon Peninsula, Newfoundland, were examined for metazoan parasites, during the period November 15, 1968–June 12, 1969. Eight genera of helminths (two of Monogenea, three of Digenea, one each of Cestoda, Nematoda, Acanthocephala) and one of parasitic copepods (Ergasilus) were recovered. This number includes one new host record and two new host records for Newfoundland.
Reproductive Isolation Between Two Sympatric Dace, Rhinichthys atratulus and R. cataractae, in Manitoba
Authors: Bartnik Victor G.
Published: April 2011

The Mink and Valley rivers, Manitoba, contain two sympatric species of dace (Cyprinidae: Rhinichthys). These fishes, although interfertile, have never been reported to hybridize in nature.Seasonal isolation is only partially developed, since overlap in time of spawning exists. During spawning, adults of the two species tend to occupy different habitats, the Great Lakes longnose dace Rhinichthys cataractae cataractae being most abundant in water velocities faster than 45 cm/sec and the western blacknose dace R. atratulus meleagris in water velocities less than 45 cm/sec; but some overlap exists. However, the place of spawning of the two species is distinctly different. Nests of longnose dace were found in water velocities exceeding 45 cm/sec with large stones, whereas nests of blacknose dace were found in slower water velocities in gravel. The patterns of spawning behaviour of these two cyprinids reveal marked differences and obvious incompatibilities. Males of both species actively defend territories prior to spawning but show distinct preferences for conspecific females over other females. Observations further indicate that females are receptive only to patterns of courtship behaviour shown by males of their own species.The combination of different places of spawning and patterns of behaviour is considered to be a powerful barrier to hybridization.
Polymorphisms of Esterase Isozymes in the American Lobster (Homarus americanus)
Authors: Barlow John , Ridgway George J.
Published: April 2011

Five groups of esterase active bands were found after electrophoretic separation of extracts of heart tissue of lobsters (Homarus americanus) on starch gels. Each group consisted of one or more bands that were distinguishable from other groups by their electrophoretic mobility, substrate specificity, and susceptibility to various inhibitors. Groups designated I–IV are carboxylesterases; group V is a cholinesterase. Individual variations were observed in groups I, II, and V. The observed polymorphisms in groups I and II were hypothesized as due to codominant allelic systems. The phenotypic frequencies of group I isozymes observed in two populations agreed well with the Hardy–Weinberg distributions expected for such systems. The frequencies of variant types in group II were too low for meaningful population genetic analysis. Phenotype frequencies were not correlated with sex, size of the carapace, or stage of the molt cycle. Developmental changes of esterase isozymes were observed during the first eight stages. The Es-V (cholinesterase) group and Es-II groups were present at hatching, but the Es-I group was not clearly observed until after the seventh molt. Phenotype ratios of offspring from single females supported the genetic hypothesis for the Es-I system.
Rate at which Sockeye Salmon Alevins are Evacuated from the Stomach of Mountain Whitefish (Prosopium williamsoni)
Authors: McKone D.
Published: April 2011

When adult mountain whitefish (Prosopium williamsoni) were force-fed two, five, or eight sockeye salmon (Oncorhynchus nerka) alevins in aquaria during May and June 1969, examination of the stomachs showed that the evacuation rate was 9.8–17.8% per hour, and was greater at higher than lower temperatures. Absolute rate of disappearance (grams/hour) was more rapid at higher than at lower temperatures and for larger than smaller food volumes. The evacuation rate was rapid and required only 6 hr at 11 C for complete evacuation of two alevins.
Geography and Bathymetry of Selected Lake Basins, Experimental Lakes Area, Northwestern Ontario
Authors: Brunskill G. J. , Schindler D. W.
Published: April 2011

The Experimental Lakes Area (ELA) is located at 93°30′–94°00′W and 49°30′–49°45′N at an altitude of 360–380 m above mean sea level. This area is underlain by Precambrian acid granites overlain in some areas by thin glacial drift composed largely of sand and gravel of quartz, plagioclase, and K-feldspar. The area was under glacial ice about 14,000 years B.P. (before present). With the melting of this glacial ice, ELA was situated on the eastern margin of glacial Lake Agassiz. As Lake Agassiz levels receded, the present lake basins were formed. The ELA watersheds now drain into the Winnipeg River, which is in the Hudson Bay drainage system.Mean annual temperatures in the vicinity of ELA are between 0.5 and 2.2 C, and annual precipitation is between 500 and 750 mm. Brunisols were observed over sand deposits in the ELA, but considerable variation in soil types and soil depth were also found. ELA is in a boreal (fire-controlled) subclimax forest of jack pine, black spruce, trembling aspen, and white birch. Aquatic macrophytes were scarce in the littoral zone of ELA lakes. Nearby logging operations and hunting and sport fishing have not influenced the immediate watersheds of ELA lakes.Morphometric maps and measurements are given for 16 lakes in ELA. These lakes vary from 2.5 to 33 m in maximum depth, and from 1.7 to 56 ha in lake surface area. Using estimates of precipitation, evaporation, evapotranspiration, drainage areas, and lake morphometry, a preliminary calculation of theoretical water renewal time is given for these lakes. These values range from 2.6 to 38 years.
Species of Lepeophtheirus (Copepoda, Caligidae) Recorded from the Ocean Sunfish (Mola mola) and their Implications for the Caligid Genus Dentigryps
Authors: Hewitt G. C.
Published: April 2011

Of the five species of Lepeophtheirus so far recorded from the ocean sunfish (Mola mola), L. ornatus Edwards has been previously synonymized with L. nordmanni Edwards. A comparison of specimens shows that L. insignis Wilson is also a synonym of L. nordmanni and that L. molae Heegaard is a synonym of L. hastatus Shiino. Lepeophtheirus nordmanni and L. hastatus are redescribed and compared. Lepeophtheirus hastatus can be distinguished from L. nordmanni by an accessory branch on its postantennary spine; in the female L. hastatus, the fifth legs are styliform whereas in female L. nordmanni they are lamelliform; the male of the latter species has a reduced sternal furca whereas male L. hastatus have a sternal furca extending beyond the interpodal bar.The great similarity between the two species casts doubts on most previous records of Lepeophtheirus from M. mola and the known distribution of these parasites is discussed.Since the fifth legs of L. hastatus are very similar to those found in Dentigryps Wilson, and these legs are the only distinguishing feature of this genus, the species previously placed in Dentigryps are transferred to Lepeophtheirus. The following new combinations are proposed: Lepeophtheirus curtus (Wilson, 1913) n. comb., L. litus (Lewis, 1964) n. comb., L. ulua (Lewis, 1964) n.comb., and L. longicauda (Cressey, 1966) n.comb. Lepeophtheirus lewisi nom.nov. is proposed for D. bifurcatus Lewis, 1964.
Interactions Between Some Tubificid Oligochaetes and Bacteria Found in the Sediments of Toronto Harbour, Ontario
Authors: Wavre M. , Brinkhurst R. O.
Published: April 2011

Three species of tubificid oligochaetes and seven heterotrophic aerobic bacteria were identified from the sediment of Toronto Harbour, Ontario. The relative abundance of the identifiable bacteria present in the mud and in the worm feces voided after 18 hr was established using nutrient agar medium. The results indicated a reduction in the relative abundance of bacteria by about 72% and a reduction in the variety of bacteria in the feces as opposed to those detected in the mud. After a starvation period of approximately 1 week, only one type of bacteria was detected in the feces and guts of the worms, whereas all seven were shown to be ingested at one time or another. The surviving bacterium was different in each tubificid species, but Aeromonas sp. was seen to replace this surviving species on some occasions in all three species of worm. The results suggest that the fraction of the bacterial flora investigated forms a part of the diet of tubificids, and that differences between worm species in relation to their use of those bacteria may help to explain the survival of a number of morphologically unspecialized sediment-feeding species in close physical proximity to each other.
A Comparison of a Simple Corer and an Ekman Grab for Sampling Shallow-Water Benthos
Authors: Paterson C. G. , Fernando C. H.
Published: April 2011

Estimates of the density of freshwater benthic invertebrates in shallow lentic habitats were found to be about 50% higher when samples were taken with a simple corer than when samples were taken with an Ekman grab. The use of the corer also decreased the volume of sediment collected and reduced the tediousness of examining large samples.
Subcutaneous Fibroma in Lake Trout (Salvelinus namaycush) in Quebec
Authors: Broughton E. , Choquette L. P. E.
Published: April 2011

Histological examination of a subcutaneous tumour in each of two lake trout (Salvelinus namaycush (Walbaum)) from two lakes in the province of Quebec showed it to be a fibroma. This is the first report of such a neoplasm in lake trout.
Response of Brook Trout (Salvelinus fontinalis) Populations to a Fishery
Authors: Jensen A. L.
Published: April 2011

From data in the literature, life tables are calculated for seven different brook trout (Salvelinus fontinalis) populations and used to study the mechanisms that reestablish the balance of births and deaths upset by fishing. It appears that a change in age-specific fecundity is the compensatory mechanism in brook trout.
Life History of Rainbow Trout (Salmo gairdneri) in Batchawana Bay, Eastern Lake Superior
Authors: Kwain Wen-hwa
Published: April 2011

The life history of a rainbow trout (Salmo gairdneri) population was inferred from scale readings from the years 1967–70. Of 461 scale samples examined, 58% were from fish spending 2 years in the stream, 38% were 1 year in the stream, and 4% were 3 years in the stream. Three- and four-year-old trout formed the bulk of the spawning population. Fish descending early to the lake were significantly larger at maturity than fish descending later in life. No apparent size difference between sexes was found; fish generally spent 2 years in the lake to reach sexual maturation. In the spawning population, 68% were maiden spawners and 26% were spawning for a second time. A five-time spawner was recorded. The incidence of lamprey marking of rainbow trout was 15% (1969) and 14% (1970). Ninety percent of lamprey-marked trout were larger than 450 mm in fork length and had lived in the lake for 2 or more consecutive years.
Influence of Nutrient Enrichment on Photosynthesis and Assimilation Ratios in Natural North Pacific Phytoplankton Communities
Authors: Glooschenko Walter A. , Curl Jr. Herbert
Published: April 2011

In Oregon coastal waters, upwelling was influenced in situ response to additions of nitrogen (as [Formula: see text]), phosphorus (as [Formula: see text]), and iron (as Fe–EDTA) at approximately twice the highest concentrations to be expected in the area, the response being measured as uptake of [Formula: see text] and assimilation numbers calculated from chlorophyll a data. In July and September, when up-welling was present in inshore stations, no response was seen to added N, P, or Fe. Offshore stations had significant increases in [Formula: see text] uptake and assimilation numbers. When up-welling had ceased (November or February), inshore stations showed increased [Formula: see text] uptake and assimilation numbers with N, P, or Fe. The most limiting nutrient was Fe. A mid-Pacific station north of Hawaii, a nutrient-poor area, gave large increases in production when N, P, or Fe was added. A station near the Aleutian Islands, a nutrient-rich area, did not respond to nutrient additions. Low assimilation numbers found in upwelling areas were possibly due to depletion of nutrients in the bottles used in the experiment, or to another limiting factor than the nutrients tested.
Analysis of Laboratory Experiments on Growth Efficiency of Fishes
Authors: Kerr S. R.
Published: April 2011

Paloheimo and Dickie (J. Fish. Res. Bd. Canada 23: 869–908, 1966) described a regular variation between growth efficiency and ration level of fishes, termed a "K-line." Subsequent work has either confirmed the phenomenon, or suggested that it is a special case observable only at high ration levels. Two recent published experiments are reanalyzed with the aid of an analytic model based upon the metabolic requirements of fishes. The reality of the K-line is confirmed, and it is concluded that it occurs because metabolic expenditure upon spontaneous activity increases more than proportionately to increased rations, increasing the fraction of ration energy dissipated as metabolism, and thereby decreasing growth efficiency.
Prediction of Fish Growth Efficiency in Nature
Authors: Kerr S. R.
Published: April 2011

Using an equation system based upon the requirements of searching for prey, and the physiological properties of the predator, the hypothesis that growth efficiency of pelagic predators may be importantly determined by the metabolic cost of searching for prey is examined. The equation system indicates that growth efficiency decreases when the prey organisms become either rare or small in relation to the size of the predator. The system also indicates that sustained growth requires increasingly large prey organisms even if these are increasingly rare. Review of empirical literature indicates that the system's predictions are in accord with observation.
Sampling Benthos and Substrate Materials, Down to 50 microns in Size, in Shallow Streams
Authors: Mundie J. H.
Published: April 2011

Stream bed materials, both biotic and abiotic, in the size range 50 μ–ca. 200 mm can be sampled unselectively, in shallow streams, with a simple inexpensive apparatus consisting of a box provided with an adjustable upstream inlet, and, downstream, two nets, one within the other. Collected materials are wet-sieved and the volumes of inorganic material passed by successively finer sieves are plotted as cumulative curves against a logarithmic size scale. Curves are given for materials from three contrasting habitats: a riffle, and pool, of a coastal stream, and an artificial spawning channel. Examples are also given of the densities, size distribution, and vertical stratification of invertebrates from these habitats. Applications of the method to studies on fish biology, invertebrate ecology, and geomorphology are indicated.
Determination of Fluoride in Soils by a Nonfusion Distillation pF Method
Authors: Ke Paul J. , Regier Lloyd W.
Published: April 2011

The nonfusion distillation pF method has been successfully applied to the determination of fluoride in soils. The fluoride is distilled from the soil sample with HClO4 and measured in the buffered distillate by an ion-specific fluoride electrode without any ashing or other separation operations. Soils or mud containing fluoride in the range between 1 to 700 ppm can be directly analyzed with a standard error of less than 1.5%.
Survival of Young Fish in the Discharge Canal of a Nuclear Power Plant
Authors: Marcy Jr. Barton C.
Published: April 2011

No young fish of nine species entrained in the condenser cooling-water system of a nuclear power plant survived passage to the lower end of the plant's 1.83-km (1.14-mile) discharge canal when water temperatures were above 30 C. Temperatures in the canal remained above 30 C during 95% of the period during which the fish larvae and juveniles were collected near the plant's intake. A field observation device was developed to keep alive for counting those larvae and juvenile fish that survived passage to sampling points in the system.
Magelona berkeleyi n.sp. from Puget Sound (Annelida: Polychaeta), with a Further Redescription of Magelona longicornis Johnson and a Consideration of Recently Described Species of Magelona
Authors: Jones Meredith L.
Published: April 2011

Magelona berkeleyi n.sp. is described from Puget Sound, Washington. It is most similar to M. filiformis from Great Britain and M. lenticulata from South Vietnam. Detailed studies of M. longicornis, utilizing refined dissection techniques, reveal the presence of a number of diagnostic structures heretofore overlooked. Comments concerning the differentiation of nine valid recently described species (since 1963), relative to previously known species, are made.
New Distribution Records of Reptant Decapod Crustacea, Including Descriptions of Three New Species of Pagurus, from the Waters Adjacent to British Columbia
Authors: Hart Josephine F. L.
Published: April 2011

Three hermit crabs, Pagurus caurinus, P. quaylei, and P. stevensae, from British Columbia are described as new. Calastacus quinqueseriatus Rathbun, Paguristes ulreyi Schmitt, Pagurus cavimanus (Miers), P. samuelis (Stimpson), Parapagurus pilosimanus Smith, Munidopsis quadrata Faxon, and Chionoecetes tanneri Rathbun have not been recorded from the area between 48° and 55°N and 123° and 135°W, and also show considerable extensions of the known ranges. Within the confines of the same area, Callianassa gigas Dana, Paguristes turgidus (Stimpson), Pagurus cornutus (Benedict), P. hemphilli (Benedict), Orthopagurus minimus (Holmes), Petrolisthes cinctipes (Randall), Sceleroplax granulata Rathbun, Pinnotheres pugettensis Holmes, P. taylori Rathbun, and Planes marinus Rathbun are reported with extensions to known ranges. Pagurus capillatus (Benedict), P. tanneri (Benedict), Paralomis verrilli (Benedict), and Lithodes couesi Benedict are recorded, apparently for the first time from British Columbia, although known from both north and south of this area.
A Biochemical and Cytological Study of the Longnose Sucker (Catostomus catostomus) and Large and Dwarf Forms of the White Sucker (Catostomus commersoni)
Authors: Beamish R. J. , Tsuyuki H.
Published: April 2011

White (Catostomus commersoni) and longnose (C. catostomus) suckers possess diploid complements of 98 chromosomes, including metacentrics, submetacentrics, and acrocentrics. White sucker karyotypes differ consistently from longnose karyotypes by the presence of an additional four metacentrics. The karyotypes of the size and age at maturity of variants of white suckers were indistinguishable. Biochemically, longnose and white suckers are distinctive with respect to muscle myogens, hemoglobins, serum esterases, serum and muscle lactate dehydrogenases, and serum transferrins. The last group of proteins provides a clear genetic separation of the large-sized, late-maturing, and the dwarf, early-maturing white suckers. The former is polymorphic for serum transferrins.
Egg Proteins of Coho Salmon (Oncorhynchus kisutch): Chromatographic Separation and Molecular Weights of the Major Proteins in the High Density Fraction and their Presence in Salmon Plasma
Authors: Markert J. R. , Vanstone W. E.
Published: April 2011

The molecular weights of the three major proteins in the soluble fraction of coho salmon (Oncorhynchus kisutch) eggs were found to be: lipovitellin, 390,000; β′-component, 30,000; and phosvitin, 27,000. Immunological techniques showed that these proteins were present in the plasma of sexually maturing female coho and of estrogenized prepuberal coho of both sexes but not of sexually maturing males or nonestrogenized prepuberal coho. These findings support the previous postulation that the β′-component should be classified not as a livetin but as an egg protein, as are lipovitellin and phosvitin.
Attached Algae on Artificial and Natural Substrates in Lake Winnipeg, Manitoba
Authors: Evans D. , Stockner John G.
Published: April 2011

The attached algal assemblage on navigational buoys and natural rock substrate in Lake Winnipeg in 1969–70 was examined, in the fall after 145 days growth, as part of an overall limnological survey of this important Canadian Great Lake. Only three phyla were represented: Cyanophyta, Chlorophyta, and Chrysophyta (Bacillariophyceae). Green and blue-green algae were more abundant in the south basin, and diatoms were more common in the more oligotrophic north basin. Ulothrix zonata occurred only on substrates in the north basin, and Cladophora cf. callicoma was found only in the south basin. On both natural and artificial substrates a distinct zonation pattern related to water transparency or available light was prevalent. Preliminary results indicated that light was the most important physical factor affecting growth and specific composition of attached algae on substrates in Lake Winnipeg. Biomass values from all stations (dry weight) ranged from 1.7 to 29.1 mg/cm2; with the greatest values consistently occurring between 10 and 25 cm deep on buoys in the south basin. Diatom density and diatom volume were estimated from buoy samples and varied respectively, within the range 2.00 × 105–6.65 × 106 diatoms/cm2 and 0.32–10.00 mm3/cm2. Though direct evidence is lacking, it appears that nutrients may limit growth of attached algae in the north basin, whereas in the south basin, light is the major limiting factor. The specific composition of the algal assemblages on particular buoys was more related to the physical–chemical features of a major river plume in close proximity to the buoy than to a homogeneous Lake Winnipeg water mass. This factor, together with greater turbidity in the shallower south basin, is largely responsible for the observed heterogeneity among the attached algal assemblages in Lake Winnipeg.
An Explanation for the Warmwater Intrusion off the British Columbia Coast
Authors: Thomson Richard E.
Published: April 2011

An explanation is given for the well-known annual variations in the northward penetration of relatively warm water off the British Columbia coast. At the top of the permanent halocline, a characteristic feature of the region, both the onshore Ekman transport, resulting from a northward meridional wind-stress component, and the relative warmth of the upper oceanic layer in winter are suggested as being responsible for these variations. At the bottom of the halocline, which lies below the depth of direct surface influence, comparison of the northward meridional wind-stress component with the temperature variations suggests that other processes besides the direct effect of Ekman transport are important in determining the variations at that level.
Seasonal Distribution of Chondrococcus columnaris Infection in River Fishes as Determined by Specific Agglutinins
Authors: Fujihara M. P. , Hungate F. P.
Published: April 2011

River fish populations infected with Chondrococcus columnaris disease were surveyed by measurements of C. columnaris agglutinating antibodies in blood sera of fishes and by isolation of the pathogen using microbiological plating methods. Agglutinins were demonstrated in all 13 fish species collected except whitefish (Prosopium williamsoni). Blood serum from samples of fishes at four Columbia River sites during 1965 and three Columbia River sites and one Snake River site during 1969–70 demonstrated single annual cycles of C. columnaris antibody production. During the two annual sampling periods, the magnitude of antibody titers and frequency of fish with agglutinins increased in warm water and declined in cool water. The rise in titers occurred after a winter low, and usually followed the period when the first C. columnaris organisms were isolated from native fish. Agglutinating titers up to 1:5000 were found but most peak titers were between 1:320 and 1:640.
Ecological Notes on a Lake-Dwelling Population of Longnose Dace (Rhinichthys cataractae)
Authors: Gee John H. , Machniak Kazimierz
Published: April 2011

Longnose dace were found from early July to September in onshore waters on the east side of Hecla island in the southern basin of Lake Winnipeg. They were most abundant on rocky substrates, where they spawned in early July. It is suggested that at other times of the year these fish occupy deep channels between islands where current is present. While in onshore waters fish less than 5 g adjusted their buoyancy by altering swimbladder volume in response to presence or absence of wave action. Swimbladder volume was similar to that of river-dwelling populations of this species.
A Simple Fish Tag Suitable for Long-Term Marking Experiments
Authors: White W. J. , Beamish R. J.
Published: April 2011

A simple, inexpensive fish tag that allows for growth of the fish is described. Growth rates of smallmouth bass were not significantly affected by tagging. The rate of retention on smallmouth bass was much higher than that for a tag described by Fraser but rates of retention of the two tags on largemouth bass were not significantly different. Estimated rates of tag loss were 15% after 1 year for smallmouth bass and 17% after 3 years for largemouth bass. Observed tag losses from white suckers over 3 years were only 0.6%.Using this method, two or three persons can conveniently tag fish at a rate of approximately 30 per hour.
Size at Maturity in the Male Alaskan Tanner Crab, Chionoecetes bairdi, as Determined by Chela Allometry, Reproductive Tract Weights, and Size of Precopulatory Males
Authors: Brown Ralph B. , Powell Guy C.
Published: April 2011

An Alaskan Commercial Fishery for tanner crab, Chionoecetes bairdi, has recently developed. Only males are legally taken. No size limit exists and the objective of the study was to determine size at sexual maturity as a biological basis for maintaining male brood stocks in adequate numbers. Morphometric measurements, reproductive tract weights, and size of precopulatory males indicate that 50% of the males are mature at about 110-mm carapace width. Using commercial catch size frequency data, the proportion of immature males in the commercial catch was interpolated at less than 3%.
Effect of Salmon Gonadotropin on In Vitro Maturation of Oocytes of a Catfish, Heteropneustes fossilis
Authors: Sundararaj Bangalore I. , Goswami Shashi V. , Donaldson Edward M.
Published: April 2011

Salmon gonadotropin failed to induce in vitro ovulation of catfish oocytes at concentrations of 1–40 μg/ml. This observation is consistent with the view that gonadotropin may not act directly on the ovary of catfish in inducing ovulation.
The American Eel (Anguilla rostrata) in Eastern Lake Ontario
Authors: Hurley Donal A.
Published: April 2011

The life history of eels in Lake Ontario was studied by measuring, tagging, and releasing about 1500 individuals between 1958 and 1966. The smallest eels captured were from 295 to 318 mm long. Presumably they entered the lake at about age III–IV at lengths of 200–300 mm. Otoliths of eels from the lake showed a range in age between IV and XVIII, while those of smaller eels from the Ottawa River ranged between age II and IX. The length–weight regressions showed two distinct growth phases: one from about 480 mm to 790 mm, the other from about 830 mm to 1080 mm. Growth of the orbital diameter, interorbital distance, and pectoral fin length in relation to total length was not obviously related to sexual maturity. Eels that emigrated from the lake had a greater weight–length ratio than those that remained in the lake for another year. Of 917 tagged eels transplanted within Lake Ontario, 28 were recaptured near and 18 recaptured far from the original capture site. Although the results are inconclusive, there is a suggestion that eels have home territories within the lake.
Postglacial Dispersal of Four Deepwater Fishes on the Basis of New Distribution Records in Eastern Ontario and Western Quebec
Authors: Dadswell M. J.
Published: April 2011

Occurrences in 130 new localities in eastern Ontario and western Quebec are given for the fishes Cottus ricei, Myoxocephalus quadricornis, Pungitius pungitius, and Percopsis omiscomaycus. A total of 189 localities for these fishes is now known within this area. The distributions of these species are closely associated with the maximum extent of the large, interconnected, Wisconsin glacial lakes, their outlet channels, and areas inundated by postglacial marine waters. Although all four fishes dispersed primarily by means of the proglacial waters between 17,000 and 6000 years ago, C. ricei, P. pungitius, and Percopsis omiscomaycus have dispersed short distances beyond the glacial lake–marine boundaries and are probably still dispersing as drainage systems adjust themselves to postglacial rebound. Dispersal was probably north and eastward from a Mississippian refugium.
The Limnology and Fishes of Oligotrophic Glacial Lakes in North America (about 1800 A.D.)
Authors: Ryder R. A.
Published: April 2011

The general limnology and fish composition of 14 North American oligotrophic lakes is described as it likely was about the year 1800, prior to the adverse effects of man-made eutrophication, exploitation, and introductions of exotic species. The general description includes glacial history and geomorphology, climate and growing season, morphometry of the lake basins, physical and chemical characteristics, macroinvertebrates, and zooplankton. Fish populations are described with respect to their zoogeographic origins and the species composition of each lake. The relative degree of environmental change brought about by the activities of man in each lake is summarized.
The Fish Fauna and Limnology of Large Oligotrophic Glacial Lakes in Europe (about 1800 A.D.)
Authors: Toivonen Jorma
Published: April 2011

An attempt is made to give a general comparative survey of the conditions obtaining in the large oligotrophic European lakes before they were changed by human activity. The material is information from the available older literature concerning the quality of the water, the plankton, the benthic fauna, and the catches of fish.
Historical Review of the Management Approach to Exploitation and Introduction in SCOL Lakes
Authors: Regier Henry A. , Applegate Vernon C.
Published: April 2011

Though environmental deterioration and destruction has always concerned fishery biologists, much of their scientific and technical activities have been related to understanding and managing direct fisheries harvests, to "improving" fisheries resources through introductions of non-native species, and to assisting the reproductive process of valued stocks with a hatchery program. The history of these approaches in western countries is sketched by time periods as follows: pre-1840, gradually developing science and technology with intensifying direct exploitation; 1840–70, human food shortages in Europe, spreading of artificial propagation and development of hatchery and stocking techniques; 1870–1900, extensive introductions of non-native species, intensified exploitation because of technological advances and market forces, great expansion of artificial propagation; 1900–45, fluctuation in exploitation partly related to the socioeconomic aspects of world wars; 1945–60, conventional hatcheries closing, new fishing gear technology, more intense exploitation, growing concerns about pollution and eutrophication; 1960–70, "back to conservation" movement.
Lago Maggiore: Effects of Exploitation and Introductions on the Salmonid Community
Authors: Grimaldi Ettore
Published: April 2011

Lake trout (Salmo trutta) is the only salmonid belonging to the original fish fauna of Lago Maggiore (north Italy): the coregonine "lavarello" (Coregonus sp.) was introduced into it in 1891, char (Salvelinus alpinus) in 1910, and the coregonine "bondella" (Coregonus monophthalmus) in 1950. This last introduction heavily affected the preexisting population of fish, bringing about the almost complete disappearance of both "lavarello" and char. The increase of human population within the watershed, as well as the modified pattern of its distribution, seem to have played a major role in speeding up the trophic evolution of Lago Maggiore during recent years. However, as far as fish is concerned, it is very difficult to distinguish changes really due to eutrophication from those attributable to other human interventions, such as introductions of exotics, destruction of spawning grounds in the main tributaries, alterations in shore structure, and very heavy fishing pressure on pelagic as opposed to littoral fish.
Effects of Fisheries Exploitation on Salmonid Communities in Oligotrophic Lakes
Authors: Regier Henry A. , Loftus Kenneth H.
Published: April 2011

In many oligotrophic lakes intense fisheries exploitation preceded severe cultural eutrophication by several decades at least, except perhaps in stream and inshore areas near shore. Attempts to infer the effects of exploitation from historical fisheries data must allow for the high rates of capture associated with the "fishing-up" process that follows initiation of a new fishery, introduction of a new gear, change in capture or vessel technology, etc. The nature of the fishing-up process is examined in some detail. Interactions of new species introduction and of eutrophication with exploitation are outlined.Within the salmonids, different taxa appear to respond somewhat differently to exploitation stress. Some taxa appear to have greater capabilities to compensate for this stress than others. Responses of the taxa are examined in the context of well-known properties of their niches and population variables.Some inferences concerning responses at the community level are proposed. Compensatory capabilities seem directly related to the degree of eutrophy of the lake. Events such as the virtual disappearance of taxa, or eruptions of new taxa, and the relative variability in year-class abundance of dominant taxa, are examined in this context.
Effects of Species Introductions on Salmonid Communities in Oligotrophic Lakes
Authors: Christie W. J. , Fraser J. M. , Nepszy S. J.
Published: April 2011

Adequate documentation was often wanting for interpretation of conditions surrounding the success or failure of an exotic. There were also known differences in species composition and other circumstances which made comparisons between SCOL lakes difficult.Successful colonization appeared possible where a sufficiently plastic new species found a niche either temporarily or permanently void. The lack of normal ecological constraints favored the explosion of a colonist, and examples were found which indicated both physiological and behavioral adaptation to permit establishment. The data suggested predation may be important in suppressing invaders. The higher diversity of littoral fish communities provided greater resistance to colonists. The role of exploitation in the fate of any colonist seemed chiefly in its effect on diversity and on stock oscillations. Eutrophication favored the success of colonists through continued destabilization of communities. It was suggested that management should proceed towards greater diversity to minimize the chances of outbreaks of pest fishes.
Evidence that Pacific Ocean Perch (Sebastes alutus) in Queen Charlotte Sound Form Aggregations that Have Different Biological Characteristics
Authors: Gunderson Donald R.
Published: April 2011

Pacific ocean perch (Sebastes alutus) in market samples from Queen Charlotte Sound showed considerable variation in mean length, even when narrowly defined month-depth strata were considered. Available evidence indicated that there was also considerable between-sample variability in growth. Both phenomena were attributed to a tendency for commercially exploited Pacific ocean perch to form distinct aggregations, each with different biological characteristics. The relevance of aggregating behavior to age and growth analyses is discussed.
Effects of Eyestalk Removal and Ecdysterone Infusion on Molting in Homarus americanus
Authors: Flint R. Warren
Published: April 2011

Techniques of inducing precocious molting by introduction of the steroid ecdysterone were studied on the American lobster, Homarus americanus. The results indicate that ecdysterone, at the dosages used, while accelerating premolt processes, sufficiently disrupts the normal sequence of molting. Destalked intermolt stage C lobsters were infused with ecdysterone, in quantities ranging from 1–6 μg/g body weight. Proecdysis was shortened, particularily in lobsters receiving more than 2 μg/g body weight of the steroid. They reached ecdysis 13.8 days (average) after infusion but showed no increase in limb bud growth and died during or immediately after ecdysis. Lobsters with eyestalks infused with Ringer's solution (3% NaCl), ethyl alcohol, β-Sitosterol, or ecdysterone failed to shorten their intermolt duration near 13.8 days.It appears that, in H. americanus, removal of both eyestalks does not induce precocious molt as in other decapod crustaceans, but this animal exhibits a limb bud growth during the intermolt cycle, similar to what other investigators have found for other decapods.
Benthos Trapped Leaving the Bottom in Bideford River, Prince Edward Island
Authors: Thomas Martin L. H. , Jelley Elizabeth
Published: April 2011

Inverted funnel traps, designed to catch animals swimming up from the bottom, set in Bideford River estuary, P.E.I., during the summer of 1969 caught numerous benthic and hyperbenthic invertebrates. Many crustaceans generally considered to be planktonic appeared to enter the substratum during the day and to leave it at night. Several polychaetes, some of which were not known to swim, were regularly collected. The average catch per square meter per day was 23 individuals, amounting to 0.08 g (decalcified dry weight).
Failure to Observe Changes in Selected Metabolites Following Removal of the Stannius Corpuscles from the Freshwater North American Eel, Anguilla rostrata
Authors: Butler David Gordon
Published: April 2011

There were no measurable changes in plasma glucose, protein, or free fatty acid concentrations in the freshwater North American eel, Anguilla rostrata, 2 weeks after excision of the Stannius corpuscles. Liver glycogen concentrations were normal but muscle glycogen increased. Plasma Na decreased and K and Ca increased. These data indicate that secretions of the Stannius corpuscles are primarily concerned with ionoregulation.
Marine Growth of Atlantic Salmon (Salmo salar) in the Northwest Atlantic
Authors: Allen K. Radway , Saunders Richard L. , Elson Paul F.
Published: April 2011

The fishery for Atlantic salmon in the west Greenland area has provided useful data for the study of marine growth of salmon. Length data from seaward migrating smolts, post-smolts, and 1-, 2-, and 3-sea-winter feeders taken at sea and 1-, 2-, and 3-sea-winter spawners taken by commercial fisheries, angling, and research traps, have been used to construct a tentative growth curve. Fish which spawned after 1 sea-winter (grilse) were smaller at the time of spawning than fish of the same smolt-class which had not matured but were still actively feeding at sea. Similarly, 2-sea-winter spawners were smaller than salmon which would not have returned until after a third sea winter. The growth rate of salmon during the summer prior to spawning was lower than that of fish which would have spawned a year or more later and appears to be about the same as that during the preceding winter.