bluuebunny/crossref_metadata_2025 huggingface dataset:
Limnology and Trout Angling in Charlotte County Lakes, New Brunswick
Authors: Smith M. W.
Published: April 2011

Limnological conditions were studied in eight lakes ranging in area from 20 to 73 ha. and in mean depth from 2.4 to 7.0 m. Summer thermal stratification occurred in five, while three were subject to mixing throughout by winds. August mean water temperatures varied from 14.9° to 22.0 °C. Lowest mean dissolved-oxygen content was 71 per cent saturation although pronounced summer hypolimnal deficits developed in the stratified lakes. The lakes lie in a wooded area of poor soils, underlaid with granite rocks. Bicarbonate content ranged from 5.1 to 11.1 mg./l. Phosphate P was usually < 10 mg./cu. m., even in hypolimnia. Total P averaged about 15 mg./cu. m. with extremes of 5 and 34 mg. Allochthonous humic extractives coloured the waters in varying degree (5 to 59 p.p.m.). Adverse edaphic factors conditioned a low level of productivity. Desmids were qualitatively prominent in the plankton. Rooted aquatic vegetation was generally a minor feature. Dominant bottom organisms were Hyalella, Amnicola and sphaeriids in shallow and Chaoborus and chironomid larvae in deeper water. Fish fauna consisted of 18 species; at least speckled trout, eel, lake chub and banded killifish were common to all lakes.Yields of speckled trout to anglers were assessed by creel censuses. Rate of capture averaged 0.3 per rod-hour over a seven-year period. Average annual yield was 0.65 kg./ha. Trout in their third (22 cm., 130 g.) and fourth (29 cm., 263 g.) years of age made up 85 per cent of catches. Growth rates were similar in all lakes. Introduced trout contributed little unless planted at angling size and cropped within a year. The supply of young native trout was apparently sufficient to utilize full trout-producing capacities of these lakes.
Growth and Triaenophorus Parasitism in Relation to Taxonomy of Lake Winnipeg Ciscoes (Leucichthys)
Authors: Keleher J. J.
Published: April 2011

Four species of Lake Winnipeg ciscoes (Leucichthys, Coregonidae) were found to differ in several biological characteristics thus supporting their validity as species. L. nigripinnis and tullibee attained a larger size than either nipigon or zenithicus. The curves of growth differed for the four species. L. nipigon had a higher incidence of infection by the pseudophyllidean tapewom, Triaenophorus crassus, than did the other three species. There was no evidence of common relationship among three species between infection and age of host.
Contribution to the Study of the Fishes of Ungava Bay
Authors: Dunbar M. J. , Hildebrand H. H.
Published: April 2011

The aquatic environment of the Ungava Bay area and watershed is described. Forty-four species of fishes are recorded, belonging to twenty-one families. Twenty-nine are marine forms, two are anadromous, and thirteen are predominantly or entirely freshwater forms. Seventeen are new records for Ungava Bay, and a few are new for the whole of the Canadian Eastern Arctic. The marine piscine fauna is shown to be in the main subarctic, containing such arctic-subarctic forms as Salvelinus alpinus, Reinhardtius hippoglossoidès, Gymnocanthus tricuspis, Icelus bicornis, Aspidophoroides olriki, Lumpenus fabricii, etc., and subarctic-boreal species such as Salmo solar, Gadus callarias, Sebastes marinus, Liparis atlanticus and Mallotus villosus. More strictly arctic species in the fauna are Boreogadus saida, Triglops nybelini and Oncocottus quadricornis; there are two Atlantic boreal species recorded, Faralepis rissoi kröyeri and Lampanyctus crocodilus, and the remainder are fishes of wide north-south range, found in all three zones (arctic, subarctic, boreal), such as Somniosus microcephalus, Myctophum glaciale, Ammodytes dubius, Triglops pingeli, Eumicrotremus spinosus, Liparis tunicatus, Lumpenus maculatus, Lycodes reticulatus.
The First Record of the Smooth Lump-Sucker, Cyclopterichthys ventricosus (Pallas), in British Columbia Waters
Authors: Clemens W. A. , Wilby G. V.
Published: April 2011

not available
Limnobiology of Cowichan Lake, British Columbia
Authors: Carl G. Clifford
Published: April 2011

Cowichan Lake is 34 kilometres long, up to 4 kilometres wide and up to 150 metres deep, with an area of 62 square kilometres. Its average depth is 51 metres. Its shores are of precipitous rock for over half their length, the remainder being boulders or gravel, with a very little marsh.Summer surface temperatures are usually close to 20 °C., while the winter minimum in 1938 was 5.0°. Oxygen is generally abundant in the lake, the lowest value observed being 3.4 cc. per litre, just before the fall overturn (November 24, 1939). The reaction of the water is alkaline (pH 7.0–7.8), and its bicarbonate content was 18–22 mg. per litre (as CaCO3).Lists are presented of organisms collected in the lake. The plankton is reasonably rich in variety but was poor in quantity, in 1940 at least. Bottom organisms also are not abundant. Two species of lampreys and three fishes were found in the lake, plus a number of Salmonidae whose occurrence is described elsewhere.
Movements and Decline of Large Quoddy Herring
Authors: Huntsman A. G.
Published: April 2011

Development, beginning in 1876, of heavy fishing for "sardines", the yearling herring available in and near Passamaquoddy Bay between New Brunswick and Maine, was followed by decrease in numbers of older fish. The very local and very fat "Quoddy River" herring disappeared promptly. The immense accumulated stock of large spawning herring lasted ten years or more after recruitment was thus greatly reduced. This stock was being coincidently shifted from the Quoddy region, apparently owing to reduced rainfall.The normal seasonal shifting of these fish is between the outer side of Grand Manan Island in summer and near the mainland in winter. In midsummer of 1877, their numbers at Grand Manan began to diminish and for four years remained very low. They were as abundant as ever in winter near the mainland, but farther from shore and more numerous eastward. They appeared inside the Reversing Falls of the Saint John River, whose outflow goes to Grand Manan, in all four years of their scarcity at Grand Manan. Large herring appeared in unexampled numbers at Quaco, east of Saint John, from 1878 to 1881 and then declined. A movement across the Bay to Nova Scotia became evident by a marked rise in Annapolis County in 1881, and, farther in, in Kings County in 1882, in each case lasting for four years and not going beyond the mouth of Minas Channel. These fish seemed to make the circuit of the Bay, affecting catches at its head and on to the New Brunswick side, with return to the Saint John outflow by 1884. Farther out, other lots reached the Nova Scotian coast from Digby to Cape Sable in 1881, remained high for four years and then declined. By 1891, catches everywhere were down to a very low level, indicating exhaustion of the stock.
The Effect of Fasting on the Bacterial Flora of the Intestine of Fish
Authors: Margolis Leo
Published: April 2011

Sixteen bullheads (Ameiurus nebulosus) and three speckled trout (Salvelinus fontinalis) were kept in complete starvation for periods of time varying from one to two months and seven to ten days respectively. They were then examined, by culture methods, for the presence of bacteria in the intestine. Fifteen bullheads and the three trout did not yield bacteria. A Pseudomonad was obtained, in small numbers, from the intestine of one bullhead. Three bullheads and two trout examined two hours after the last feeding yielded intestinal bacteria in large numbers. In non-feeding fish, bacteria are usually absent from the intestine.
The Exchanges of Fresh and Salt Waters in the Bay of Fundy and in Passamaquoddy Bay
Authors: Ketchum Bostwick H. , Keen D. Jean
Published: April 2011

The results of 385 previously published hydrographic stations in the Bay of Fundy are summarized, and the average distribution of salinity at various depths is derived from these data.The total quantity of river water accumulated within the Bay of Fundy is equivalent to the quantity introduced by the rivers during a period of about 76 days.The exchange ratios for tidal excursion segments of the Bay of Fundy range from 0.17 in the neighborhood of Cape Chignecto to 0.056 in the segment immediately south of Grand Manan. In the upper tidal reaches of the Petitcodiac River and of Minas Basin the exchange ratios are about 0.95.The estuary of the St. Croix River has been studied and calculations indicate that about 15 tides, or 8 days are required on the average to replace one day's river flow. The exchange ration in this case range from 0.905 to 0.30.From a summary of existing data in Passamaquoddy Bay it is calculated that the total accumulation of river water is equal to the quantity introduced by the rivers in a period of about 16 days.
Methods of Plankton Collection and a Description of a New Sampler
Authors: Langford R. R.
Published: April 2011

A discussion of the composition and distribution of plankton organisms forms a basis for the presentation of a critical review of methods of plankton collection. The quantitative sampling of plankton by pumps, water samplers, tow nets, plankton traps and the Clarke-Bumpus sampler is discussed. Data of a comparative nature dealing with some of the more usual methods are presented. A new instrument, the Toronto Sampler, developed at the Ontario Fisheries Research Laboratory, is described and its performance is assessed.
Factors Influencing the Growth of Phytoplankton
Authors: McCombie A. M.
Published: April 2011

In reviewing the literature dealing with the influence of physical, chemical and biochemical factors on the development and decline of phytoplankton pulses, this paper first outlines the seasonal cycle of phytoplankton pulses which occurs in many parts of North America and then presents evidence that this cycle is caused chiefly by the seasonal change in water temperatures resulting from the change in solar radiation. The way in which this cycle is sometimes obscured by irregular changes in phytoplankton numbers caused by local conditions of weather or nutrient supply is next illustrated. The climate, weather and chemical conditions are then resolved into the components light intensity, duration of illumination, temperature, concentration of nutrients, ionic balance and pH, and these are classified according to specific effects on the growth and survival of plankton algae as limiting, controlling and lethal factors. The roles of factors originating within the organisms (i.e., autotoxins and antibiotics) are also considered. The discussion of laboratory investigations leads to certain criticisms of present culture methods and to some reinterpretation of observations obtained in some of these investigations. Finally, this paper illustrates the phenomenon of acclimation as it applies to phytoplankton, and it stresses the need for adequate prehistories of culture stocks in order that the results of different investigations can be validly compared.
On the Age, Growth, Migration, Reproductive Potential and Feeding Habits of the Arctic Char (Salvelinus alpinus) of Frobisher Bay, Baffin Island
Authors: Grainger E. H.
Published: April 2011

The Arctic char (Salvelinus alpinus Linn.) was studied, in the summers of 1948, 1950 and 1951, about the mouth of the Sylvia Grinnell River, Frobisher Bay, Baffin Island.Otoliths are shown to be reliable age indicators and are used for age determination. Because of deficiencies in the sampling of the fish a calculated growth curve has been constructed. The calculated growth rate is obtained by showing the relationship between otolith width and fish length and expressing it in the equation: log (fish length) = −1.503 + 1.982 log (otolith width). The relationship between otolith ring diameter and fish age is demonstrated, and from these two relationships the lengths of fish at earlier ages are calculated.The char grow very slowly, and reach an age of more than 24 winters. They migrate to the sea in late June and return to fresh water from late July until September. The first movements to the sea probably occur during the fifth, sixth and seventh summers. Sexual maturity in the females is reached at a length of about 45 cm., and at an age of approximately 12 winters. Egg counts of maturing fish averaged 3,589. Only about 33 per cent of the females over 45 cm. were maturing. At least 30 food species were found in the stomachs.Additional growth, fecundity and food studies were made on small samples from George River, Herschel Island and Adlorilik.
The Use of Catch-Effort and Tagging Data in Estimating a Flatfish Population
Authors: Ketchen K. S.
Published: April 2011

By a modification of the DeLury method an estimate is made of the stock of lemon sole (Parophrys vetulus) on the fishing grounds in Hecate Strait, British Columbia. The method is based on (1) the trend in catch of tagged fish per unit of effort in relation to accumulated catch of tagged fish, and (2) the trend in catch of untagged fish per unit of effort in relation to accumulated catch of untagged fish. At the start of the experiment 4.72 million pounds are estimated to have been present, while during the experiment 3.74 million pounds entered the area of fishing, 3.26 million pounds emigrated from it, and 2.54 million pounds were caught.A Petersen-type estimate based on the ratio of tagged to untagged fish was 4.70 million pounds present at the start of the experiment—practically identical with the one derived from catch-effort information. Total population for the year (1950) is estimated as 9.8–12.2 million pounds, including catch and possible emigration prior to the experiment, the stock on the fishing grounds at the start of the experiment, and the immigration subsequently.The average annual survival rate of age VII – age IX lemon soles in Hecate Strait has decreased from 0.770 to 0.614 during the period of growth of the fishery, 1944–1951. From this difference the average rate of exploitation is estimated as 16 to 20 per cent and the average population as 8.9 to 11.5 million pounds. Since this range is nearly the same as the range described above, it is concluded that almost the whole of the Hecate Strait stock was accessible to fishing in 1950, which was a year of unusually high production.
Observations on the Trout-Perch Percopsis omiscomaycus (Walbaum), at Heming Lake, Manitoba
Authors: Lawler G. H.
Published: April 2011

Trout-perch of Heming Lake attain III years of age and 90 mm. in fork length. In May they ascend small tributaries to spawn on silt and boulder bottoms, at a temperature of 40°–50°F. Average egg content was 349, with range 210–728 in 11 fish. Trout-perch taken in the lake were infested with 0 to 6 cysts each (av. 1.4) containing procercoids of the cestode Triaenophorus stizostedionis. Most cysts were in the liver or gonads, very few in the muscle. Trout-perch were eaten in large numbers by pike, Esox lucius, and much less frequently by walleye, Stizostedion vitreum. Only the latter contained adult Triaenophorous stizostedionis.
The Behaviour of Juvenile Pacific Salmon, with Particular Reference to the Sockeye (Oncorhynchus nerka)
Authors: Hoar William S.
Published: April 2011

Behaviour patterns of juvenile sockeye salmon in fresh water are compared with those of chum and coho salmon. Both sockeye and chum fry are schooling fish, responding positively to currents and avoiding shallow waters. Of the two species, chums, however, form more active schools, travel more rapidly, have a less marked cover reaction and prefer stronger light and shallower water. Sockeye smolts, in contrast to coho smolts, are more active, show little thigmotactic and territorial behaviour and a more persistent response to current. The experimental findings are discussed in relation to the migratory behaviour of these fish. It is suggested that sockeye fry, emerging from cover as the light intensity falls are displaced downstream after dark. Moderate activity and a marked preference for deep water are mechanisms postulated for continued residence of sockeye fry in lakes. Further it is suggested that the smolt exodus is due to heightened general activity, both day and night, associated with strong response to current. This brings sockeye smolts into the outflow from the lake where they hold position during the day but are displaced down the river after dark. Coho smolts, responding less vigorously to currents and maintaining a measure of contact with specific objects in their environment, move seaward more slowly than sockeye.
Stream Studies on Planted Atlantic Salmon
Authors: McCrimmon H. R.
Published: April 2011

Plantings of Atlantic salmon fry were made in the Duffin Creek system in order to determine the survival and distribution of salmon under a variety of stream conditions. Population studies estimated that the three general June plantings resulted in an average survival of 12.7 per cent until the autumn of the first year, 9.2 per cent until the autumn of the second year. High summer temperatures were lethal to the salmon in certain parts of the creek system. Over the balance of the planted part, the greatest mortality occurred soon after plantings when heavy predation by other species of fish occurred. The extent of predation was determined largely by the amount of shelter available to the fry. Suitable shelter for the young salmon was limited generally to gravelly riffle areas where the degree of bottom sedimentation determined the amount of shelter offered. Other stream conditions were of minor or no importance in salmon survival. Further losses of salmon were low once the young salmon had become established in the creek system.
The Abundance and Distribution of Entomostracan Plankton at Lakelse Lake, B.C., 1949–1952
Authors: McMahon V. H.
Published: April 2011

Greatest concentrations of entomostracans at Lakelse Lake in 1949 were in the upper half of a 30-metre column. The copepods were quite uniform in horizontal distribution over the deeper part of the lake while the cladocerans tended to concentrate at the north end. A high abundance of entomostracans occurred between mid-July and mid-October. Sampling at the deepest station only may be sufficient to give an indication of the total incidence of Cyclops sp. in the lake, but a true representation of total abundance of the other entomostracans cannot be obtained by this restricted method of sampling. An apparent decline in the occurrence of entomostracans following 1949 can probably be attributed, in part at least, to a change in efficiency of the collecting nets used.
Offshore Characteristics in the Deep Waters of the Strait of Georgia as Indicated by Bathypelagic Fish
Authors: Barraclough W. E. , Waldichuk M.
Published: April 2011

An attempt is made from oceanographical observations to explain the occurrence of certain bathypelagic species of fish which have been captured in the bottom waters of the southern Strait of Georgia. It is noted that there is a considerable seaward surface Sow of water from the Fraser River. The water from intermediate depths over the continental shelf forms the inflowing deep water of Juan de Fuca Strait mixing with the Fraser River water in the turbulent channels of the San Juan Archipelago. This mixture forms the deep inflowing water of southern Strait of Georgia and the outflowing surface water of the Juan de Fuca Strait as shown by salinity distribution and current measurements. The net inward movement of deep water is suggested as an agent of transport or a directive factor for the occurrence of these fish in this region. Physical and chemical conditions of the deep water in the Strait of Georgia are shown to be only slightly different from those found in the intermediate offshore water. It is probable that a combination of factors provides conditions suitable for survival of these species in the deep water of the southern Strait of Georgia.
Polychaetous Annelids of Ungava Bay, Hudson Strait, Frobisher Bay and Cumberland Sound
Authors: Grainger E. H.
Published: April 2011

A collection of 74 species of polychaetous annelids, the greater part of which was obtained by the Calanus expeditions of 1947–1952 in Ungava Bay, Hudson Strait, Frobisher Bay and Cumberland Sound, is described. Twelve species are new records for the Canadian eastern arctic, and 2 are new for North America. The zoogeographical relationships of the known Canadian eastern arctic polychaete fauna are discussed.
Annual Growth Rings and Rate of Growth of the Giant Scallop, Placopecten magellanicus (Gmelin) in the Digby Area of the Bay of Fundy
Authors: Stevenson J. A. , Dickie L. M.
Published: April 2011

The growth rings on the valves of scallops collected from the Digby area of the Bay of Fundy are formed only once a year during the winter. Observations of special collections of small scallops have also shown the position of the first growth ring. This information has been used to construct a general growth curve from measurements of annuli on scallops from the Digby area.
Tisbe celatan. sp., a Harpacticoid Copepod from the Mantle Cavity of the Edible Mussel in New Brunswick
Authors: Humes Arthur G.
Published: April 2011

A new copepod, Tisbe celata (Harpacticoida: Tisbidae), is described from the mantle cavity of Mytilus edulis L. at St. Andrews, N.B., and its differentiation from the 27 known species of Tisbe is discussed.
Growth, Maturity and Mortality in the Relatively Unexploited Lake Trout, Cristivomer namaycush, of Great Slave Lake
Authors: Kennedy W. A.
Published: April 2011

Ages of 9,215 lake trout were determined. Length-weight and time-maturity relationships are shown. Sex ratio is 1:1. Only half the females of mature size spawn each year. There is no growth except during June to September, inclusive. There is a tremendous difference in size at a given age. Growth is much faster in one half of the lake than in the other, it is the same as or slightly slower than in lakes farther south and considerably faster than in Great Bear Lake. Seven years of commercial fishing did not increase total annual mortality by much. Mortality rate increases with age among all fish of catchable size. A given year-class probably attains maximum biomass well before most of its members reach commercial size. No significant variation in year-class strength was found.
Experimental Infection of Atlantic Cod with a Larval Marine Nematode from Smelt
Authors: Scott D. M.
Published: April 2011

Atlantic cod (Gadus callarias) and at least 13 other species of fish in Canadian Atlantic waters are intermediate hosts for a larval nematode (Porrocaecum decipiens). It is pointed out that large cod feed occasionally on infected species of fish and that, as a result, they may become infected. Experiments showed that when larval Porrocaecum from smelt (Osmerus mordax) were fed to cod, some worms passed through the wall of the stomach, crossed the coelom, and penetrated the hypaxonic muscle of the cod. It was concluded that Porrocaecum larvae, under natural conditions, are also able to pass from one species of fish to another.
Some Helminth Parasites of Canadian Pacific Whales
Authors: Margolis Leo , Pike Gordon C.
Published: April 2011

The following helminth parasites have been recorded from Cetacea caught off the British Columbia coast. Trematoda: Lecithodesmus goliath (fin whale), Lecithodesmus spinosus n. sp. (sei whale) and Ogmogaster plicatus (fin and sei whales); Cestoda: Phyllobothrium delphini (sperm and fin whales); Nematoda: Anisakis simplex (sei, Baird's beaked and sperm whales), Anisakis physeteris (sperm whale), immature Anisakis sp. (fin and humpback whales) and Crassicauda pacifica n. sp. (fin whale); Acanthocephala: Bolbosoma turbinella (sei whale). Crassicauda pacifica and L. spinosus are illustrated and described, and compared with known species of their respective genera. The variations in morphology and measurements are discussed for O. plicatus. Notes on host and geographical distribution are cited for all parasites. Lecithodesmus goliath and O. plicatus are reported for the first time from the Pacific and P. delphini was previously unknown in the North Pacific. Bolbosoma turbinella is a new record for the northeast Pacific and A. physeteris for the Pacific coast of Canada. Baird's beaked whale and possibly the sperm whale are new host records for A. simplex. The fin whale is a new host record for P. delphini and L. goliath.
Fertilization and Predator Control to Improve Trout Angling in Natural Lakes
Authors: Smith M. W.
Published: April 2011

A significantly faster growth rate by native and planted eastern brook trout followed the addition of commercial fertilizers in sufficient quantities to provide potential additional concentrations of 0.39 mg. P, 0.21 mg. N and 0.27 mg. K per litre in Crecy Lake (20.4 ha.; mean depth, 2.4), New Brunswick. Largely because trout planted as fingerlings attained suitable angling size when yearlings, the rate of capture and the yield by weight to anglers approximately doubled. The improved growth rate, but not yields, persisted into the second and third years after fertilization. Coincident was an increase in predation by fish-eating birds and mammals. With predator control and the same stocking rates, the yield of trout flesh produced in the lake increased from 0.9 to 5.9 kgm. per hectare over the next two-year period. With predator control extended to trapping eels in the lake, a second comparable fertilization with respect to concentrations of P, N and K, and a doubling of the stocking rate, a yield of 9.7 kgm. per hectare was realized. The growth rate was somewhat depressed with the heavier stocking, notwithstanding a second fertilization. Facilities for natural reproduction were poor and planted trout (fingerlings and yearlings) sustained the fishery. Maximum survivals of planted trout (all marked) to anglers' catches were 20 per cent for fingerlings and 88 per cent for yearlings. Cropping of trout of age II was thorough. For the most part, movements of planted trout (trapped in outlet) from the lake would have occasioned minor losses.Neighbouring Gibson Lake (24.0 ha.; mean depth, 4.0 m.) was fertilized with one-half of the concentrations of P, N and K applied to Crecy. Stocking with trout was at comparable rates but no predator control was exercised. Little improvement was noted in the growth of the trout. Only when yearlings were planted late in the fall and angled early in the spring was there any improvement in the anglers' catches.
Limnological and Biological Observations in the Region of the Ungava or Chubb Crater, Province of Quebec
Authors: Martin N. V.
Published: April 2011

Ungava Crater Lake, at 73° 41′ W.L. and 61° 17′ N.L., lies in a meteoritic crater of the northern Quebec tundra. The lake is nearly circular, 1.7 miles in diameter, with steep walls and a maximum known depth of 825 feet. Secchi disc transparency was 35 metres. Summer surface temperatures were 3–4 °C., of the deep water a little less. Surface oxygen was abundant, pH was 6.5–6.6. Total solids in the water were less than 20 parts per million, and hardness was only 1.7 p.p.m. Three kinds of mammals and 14 of birds were found in the crater region. Arctic char, Salvelinus alpinus, were the only fish taken in the crater lake. Specimens up to 21.8 inches fork length and 18 years old were taken; they fed on insects and other char. Char in other nearby waters grew somewhat faster but ate the same foods; mature females as small as 4.0 inches were seen. Lake trout, Salvelinus namaycush, in a lake near the crater reached 33.5 inches and 15.8 pounds. Growth was very slow, the greatest age determined being 21 years, at 13 pounds. Twenty-nine species of vascular plants were collected close to the crater.
Measuring Seepage through Salmon Spawning Gravel
Authors: Pollard R. A.
Published: April 2011

The rate of oxygen supply to salmon eggs incubating in a stream bed depends on the oxygen concentration in the groundwater and the rate of seepage through the redd. Wickett (1954) devised a simple field method of both sampling the groundwater for the determination of its dissolved oxygen content and measuring the seepage rate, using one tool, a standpipe. The theory of seepage is outlined to show the factors governing the velocity of flow through a redd. Alternative ways of measuring this velocity were examined; the best one is a modification of Wickett's procedure using a similar standpipe. A new field procedure for measuring the oxygen concentration and groundwater seepage rate in a stream bed is recommended.
A Comparison of Atlantic Sea Sturgeon with a New Subspecies from the Gulf of Mexico (Acipenser oxyrhynchus de sotoi)
Authors: Vladykov Vadim D.
Published: April 2011

The sea sturgeon, Acipenser oxyrhynchus Mitchill, occurs in the western north Atlantic Ocean from Canadian waters south to the Gulf of Mexico. Specimens taken from eastern Florida to Quebec are assigned to the typical subspecies oxyrhynchus, while 2 specimens from off Mississippi are here described as the new subspecies de sotoi. The latter differs in having a longer head, longer pectoral fins, strongly developed scutes of distinctive shape and an unusually long spleen.
Fluctuations in Abundance of the Giant Scallop, Placopecten magellanicus (Gmelin), in the Digby Area of the Bay of Fundy
Authors: Dickie L. M.
Published: April 2011

Fluctuations in total landings and in catch per boat have characterized the Digby scallop fishery since it began in 1920. An analysis of records of the fishery indicates that, although changes in fishing methods have been partly responsible for early changes in catch, their influence in recent years has been small and changes in abundance have been primarily responsible for fluctuations in the fishery since it reached its full development in the mid-thirties.Changes in abundance are assessed from analyses of catch records, special "census-fishing" techniques, submarine photography and marking experiments. Estimates from the different methods correspond.Scallops are recruited into the catchable population as six-year-old year-classes. Abundance is high when these recruited year-classes are strong, but is low when they are weak. Abundance in any year is correlated with water temperature six years previously. Both abundance and the strength of individual year-classes are correlated with water temperatures which prevailed at the time the scallops were present as pelagic larvae.It is concluded that changes in the abundance of the catchable scallop stocks result from the combined action of temperature and circulation on the pelagic larvae. Low temperatures retard larval development, and are indicative of great exchange of the water in the Bay of Fundy with outside water masses. This apparently leads to heavy losses of the larvae from the Bay, poor sets on the parent beds, weak year-classes and low abundance of the catchable stocks of six years later. High temperatures speed larval development and are indicative of a closed Fundy circulation which holds the larvae in the vicinity of the parent beds. This leads to good sets, strong year-classes and high abundance of the catchable stocks six years later.
The Collapse and Recovery of a Small Whitefish Fishery
Authors: Miller Richard B.
Published: April 2011

Pigeon Lake, Alberta, is a shallow eutrophic lake with a sandy basin, gentle contours and an area of 40 square miles. It contains whitefish, pike, yellow walleye, perch, burbot, white suckers and spottail shiners. The whitefish have been commercially exploited for many years and catch statistics are available from 1918.In 1941 a greatly increased catch of whitefish was permitted. Large annual yields continued until 1946; in 1947, in spite of considerable effort, a very small catch was made. Since this collapse fishing was prohibited in two years and light in two years. The lake now contains a normal whitefish population.Samples of the commercial catch during this period showed that the average age of the fish fell from 5.1 to 2.3 years, then, after collapse, increased to 5.7 years. Growth rates increased greatly, then decreased to the original level. Age at maturity decreased from five to two years.Calculations of the number of fish each year-class contributed to the fishery reveal that the collapse of the fishery was not due to overfishing; the weak year-classes which caused the collapse had parent year-classes of normal abundance. It is suggested that egg destruction by strong winds may have caused the weak year-classes.
On the Sharpness of Oceanographic Boundaries South of Nova Scotia
Authors: McLellan H. J.
Published: April 2011

The waters south of Nova Scotia are characterized by extremely sharp boundaries both in the horizontal and vertical planes. Temperature changes of the order of 3 Centigrade degrees per metre depth and of 1.5 Centigrade degrees in 100 metres' travel have been observed. Such boundaries must constitute significant barriers to the migration of marine life forms.
Interspecific Competition and Population Control in Freshwater Fish
Authors: Larkin P. A.
Published: April 2011

Interspecific competition is defined as the demand of more than one organism for the same resource of the environment in excess of immediate supply. When two species are "competing for a niche" the term competition has been used to include phenomena such as predation of the two species on each other, competition to avoid a parasite, etc. Making this distinction in natural situations is unrealistic. In the limited sense in which interspecific competition is defined above, it is a discrete phenomenon, which with other phenomena such as predation, can be measured as a factor involved in interaction between species.Freshwater environments offer comparatively few opportunities for specialization in fishes. In consequence many species have a relatively wide tolerance of habitat type, a flexibility of feeding habits and in general share many resources of their environment with several other species of fish. Cannibalism and mutual predation are common complications of competitive relationships between species. The organization of freshwater fish communities is thus characterized by breadth at each level of the food chain rather than by a height of a pyramid of numbers. Flexible growth rate and high reproductive potential permit fish populations to tide over unfavorable periods of competition. In these circumstances it is difficult to separate the role of interspecific competition from other phenomena as a factor of population control. As a subordinate factor, predisposing fish to loss from other causes, interspecific competition may act to influence population levels. There is need for quantitative data and mathematical models for study of the types of population interaction typical in freshwater fish associations.
The Oceanography of Chatham Sound, British Columbia
Authors: Trites Ronald W.
Published: April 2011

During May–September, 1948, an oceanographic study was made of Chatham Sound, primarily to determine, if possible, whether there was any obvious characteristic of the water in the region which could be correlated with the known migration of salmon to the spawning grounds up the Nass and Skeena Rivers. A detailed analysis of the oceanographic data is presented.The path taken by the fresh water through the sound is shown to depend on the volume of fresh water being discharged from the rivers. These reach their peak discharge in late May or early June and during this period the amount of fresh water in the sound is three to four times the average. Data obtained at anchor stations occupied for 10 to 40 hours indicate that there is a good correlation between tidal, salinity and temperature cycles.Dynamic calculations have been made of the velocities, total volume and fresh water transports. During normal river conditions, the agreement with observed velocities, and with fresh water discharges determined from gauge readings, suggests that even in these coastal waters there is an approximate balance between the transverse pressure gradient and the Coriolis force. Stations at the mouth of Portland Inlet exhibit an apparent balance at all times which suggests that transverse inertial and frictional forces are slight compared with the transverse pressure gradient and Coriolis force. Evidence of a variation in geopotential slope associated with the tides is proposed.The relatively large tidal amplitudes together with the wide and rapid fluctuations in river discharge make it exceedingly difficult to obtain reliable synoptic observations over the entire sound.
Populations of Herring (Clupea harengus L.) in Newfoundland Waters
Authors: Tibbo S. N.
Published: April 2011

Four separate and distinct populations of herring have been identified in Newfoundland waters. They are located during spawning seasons in Bay of Islands, Fortune Bay, Placentia Bay and Notre Dame Bay. They are distinguished by differences in growth, "diameter" of the scales at the end of the first year, and average vertebral counts, also by the length, age, and year-class composition of the spawning aggregations. The herring that are caught off the Labrador coast may be an older and more migratory part of the population that spawns in Notre Dame Bay. The number of vertebrae tends to decrease from south to north in the Newfoundland area, which is the reverse of what is found elsewhere, but temperature at spawning may increase from south to north for these populations. The present fishery is chiefly for large (32.4 to 36.4 cm.) and old (7.4 to 11.9 yr.) herring and it is evident that catches could be increased considerably.
Relationship of Otolith Lengths and Weights in the Haddock Melanogrammus aeglefinus (L.) to the Rate of Growth of the Fish
Authors: Templeman Wilfred , Squires H. J.
Published: April 2011

Haddock otolith lengths decline from over 5% of the total length of the fish at 14 to 17 cm. to almost 3% at 74 to 77 cm. The otolith lengths of slow-growing haddock decline less rapidly than those of fast-growing haddock. Little difference was found between otolith lengths in male and female haddock of the same length.Slow-growing haddock both from the Grand Bank and from St. Pierre Bank have heavier otoliths than fast-growing haddock at the same fish lengths. This is true not only for fish of different year-classes in the same year but also for fish of the same year-class in different years.The otoliths of male haddock of the Grand Bank exceed progressively in weight the otoliths of females of the same length after the males become sexually mature. The relative increase in otolith weight of the male fish is attributed to a probably slower growth rate after sexual maturity, which occurs earlier than in females. Similarly, the heavier otoliths of mature fish in sizes overlapping with immature fish are due to a greater age of the mature fish at these sizes. Otolith weight relative to fish weight decreased considerably with increase in fish size, and no distinct differences were apparent between otolith weights as a percentage of fish weights in slow-growing and fast-growing fish of the same length.
The Effect of Fry Plantings on Whitefish Production in Eastern Lake Ontario
Authors: Lapworth E. D.
Published: April 2011

Whitefish fry were planted in the Bay of Quinte and adjacent waters in numbers varying from 208 millions in 1927 to none in 1945. Since 50% of the commercial whitefish catch from these waters consisted of five-year-old fish, whitefish production in each of the years from 1929 to 1951 was compared to the number of fry planted 5 years previously (1924–1946). No correlation could be found between the number of fry planted and the production of whitefish 5 years later. The largest number of fry planted (208 millions in 1927) was followed by the lowest production of the entire period (95 thousand pounds in 1932). On the other hand, following no planting in 1945, production in 1950 was approximately normal (162 thousand pounds).The age composition of the commercial catch in the years 1944–1951 was determined from scale samples. By applying the age composition to the total catches in these years the contributions of the year-classes 1940–1945 have been estimated. The number of fry planted probably did not affect the contribution of these year-classes to the fishery.
The Smaller Cetacea of Eastern Canadian Waters
Authors: Sergeant D. E. , Fisher H. D.
Published: April 2011

An account is given of the known records, distribution and migrations of the smaller Odontocete whales occurring in eastern Canadian waters, with measurements of specimens obtained of the rarer species. The distribution of the abundant pilot whale Globicephala melaena (Traill) has been studied in most detail. The species' summer range includes both the offshore waters of the Labrador Sea and the coastal waters around Newfoundland. The coastal population feeds only on the squid Illex illecebrosus (LeSueur) and its movements inshore in spring and offshore in autumn follow those of the squid over the southwest Grand Bank. In some years a failure of the squid to move shorewards results in a failure of the fisheries for both squid and pilot whales in Newfoundland. The species is known to winter in an oceanic area southeast of the Grand Bank.The white-sided dolphin Lagenorhynchus acutus Gray associates with the pilot whale and apparently inhabits the same climatic zone in these waters, while the white-beaked dolphin L. albirostris Gray is found in somewhat colder waters. The killer whale Grampus orca (L.) migrates northwards in spring along the Newfoundland and Labrador coasts, its migration coinciding with that of the rorquals.New records for the waters of eastern Canada, extending the known range of each, are given for Mesoplodon bidens, Tursiops truncatus, Lagenorhynchus albirostris and Lagenorhynchus acutus.
Evolution and Distribution of the Coregonids
Authors: Smith Stanford H.
Published: April 2011

Increased knowledge of the morphological and physiological plasticity of the coregonids has minimized the significance of conflicting morphological data that have retarded the development of an evolutionary theory. Of the four phyletic lines recognized through worldwide studies, Coregonus originated in the lake and stream area of northwest Eurasia, Stenodus and Prosopium evolved in the rivers of Siberia and northwest America respectively, and Leucichthys became differentiated in the lake-studded area of northeast America. Isolation and range extension were facilitated by events of the Pleistocene epoch. Inter-continental exchange most likely took place in the Bering Strait region. Representatives of each group in its area of origin are highly variable. Range extensions of each group are characterized by lesser morphological variability and at the extremes only one or two relatively stable species remain.
The Action of Pseudomonas on Fish Muscle: 1. Organisms Responsible for Odours Produced During Incipient Spoilage of Chilled Fish Muscle
Authors: Castell C. H. , Greenough Maxine F.
Published: April 2011

Many of the odours characteristic of the earlier stages of spoilage of chilled fish muscle have been reproduced by inoculating sterile fish and fish media with pure cultures of bacteria isolated from fish. These organisms belong to the Pseudomonas and the majority are neither proteolytic nor break down trimethylamine oxide. They are chiefly achromogenic, although a few green pigmented species are included. Odour production by these organisms appears not to be inhibited by sodium nitrite. Similar odours, produced by similar types of organisms, have been observed in the past on dairy products, eggs, meat, poultry and other protein foods held in cold storage.
Influence of Intermittent Short Storage Periods at 15°F., as Encountered During Refrigerator Car Transportation, on the Quality of Frozen Cod Stored at 0°F.
Authors: Dyer W. J. , Fraser Doris I. , Ellis D. G. , MacCallum W. A.
Published: April 2011

Frozen cod fillets subjected to a 2-week period of storage at 15° F. (−9.4 °C.) after storage at 0° F. (−18 °C.) for 1, 3, 6, and 9 months, with subsequent storage at 0° F., suffered considerable deterioration in quality as measured by taste panel and protein solubility tests. Frozen fish should not be transported at temperatures as high as 15° F.
Permanence and Size of Home Territory in Stream-Dwelling Cutthroat Trout
Authors: Miller Richard B.
Published: April 2011

Gorge Creek is a small cutthroat trout stream in Alberta on the eastern slopes of the Rocky Mountains. In the summer of 1954, 98 trout were tagged with Petersen tags, weighed and returned to the pool of capture. In the same summer and in the next two, 58 of these trout were recaptured, some several times, so that, altogether, 83 records were obtained. Twenty-three records are of the first year, 35 from the second and 25 from the third.Sixty-seven per cent of the recaptures were made in the original pool or less than 200 yards from it. Of the remaining 33%, one fish had moved 1.5 miles upstream and remained there. The others had all drifted downstream. The drifters were smaller fish than those that stayed home, and they either lost weight or gained at rates considerably below normal. It is suggested these fish had been injured by the tags. The general conclusion is that each cutthroat trout of Gorge Creek has a home territory not over twenty yards long and that the whole life is spent in it.
Reactions of Juvenile Pacific Salmon to Light
Authors: Hoar W. S. , Keenleyside M. H. A. , Goodall R. G.
Published: April 2011

When given a choice between light and dark areas, schools of chum or pink salmon fry remain in the light, sockeye fry prefer the dark and coho fry show no marked preference for either. Newly emerged sockeye fry are the most strongly photonegative, remaining mostly under stones. Older sockeye fry move more into the light. Sockeye and coho smolts stay in the dark more than sockeye and coho underyearlings. Territorial and "escape" behaviour by fish in the experimental apparatus may obscure these reactions to light. Soon after emerging from the gravel, pink fry swim near the surface under low light intensity and retreat to deeper water in brighter light. Older pink fry seem indifferent to changing light. Recently emerged chum salmon fry do not respond in this way to changing illumination, although older fry tend to swim closer to the surface. This difference between pink and chum salmon fry may be related to differences in schooling behaviour and alarm responses of the two species.
The Estimation of Population Size by a Marking and Recapture Procedure
Authors: DeLury D. B.
Published: April 2011

The Schumacher and Schnabel estimates of population size are compared and reasons are given for preferring the Schumacher formula. This formula is extended to permit mortality and recruitment in the population. Confidence limits are provided according to standard regression theory.
Redescription of Lampetra ayresii (Günther) of Western North America, a Species of Lamprey (Petromyzontidae) Distinct from Lampetra fluviatilis (Linnaeus) of Europe
Authors: Vladykov Vadim D. , Follett W. I.
Published: April 2011

Lampetra ayresii (Günther), a species of parasitic river lamprey endemic to western North America, is redescribed on the basis of material from off the Skeena River, British Columbia, to San Francisco Bay, California. A neotype is designated. Transformed specimens differ from those of the European Lampetra fluviatilis (Linnaeus) in having a larger eye, a longer prebranchial and a shorter branchial region, and possibly a lower second dorsal fin, an acute rather than an obtuse caudal fin, a higher average number of trunk myomeres, and an area of dark pigment on the caudal fin. Ammocoetes differ from those of Lampetra fluviatilis principally in having a higher number of myomeres, a dark caudal spot (which distinguishes them also from ammocoetes of Lampetra planeri (Bloch), the nonparasitic brook lamprey), and an absence of dark pigment on most parts of the head and on the precursor of the tongue. Specimens from Oregon are recorded for the first time. Specimens from Mill Creek, Tehama County, California, show that this species ascends the Sacramento River farther than previous records indicated. An annotated synonymy is included. Lampetra ayresii is indicated as distinct from Ammocoetes cibarius Girard, which is regarded as identical with Entosphenus tridentatus (Richardson). Lampetra ayresii and Lampetra fluviatilis are illustrated by a number of original drawings and photographs.