bluuebunny/crossref_metadata_2025 huggingface dataset:
Annual Changes in the Oceanic-Coastal Waters of the Eastern Subarctic Pacific
Authors: Dodimead A. J. , Pickard G. L.
Published: April 2011

The temporal variations of water characteristics and currents are reviewed both for the oceanic region of the eastern Subarctic Pacific and for the bordering coastal and fjord regions.In the oceanic region, an estuarine structure prevails, namely, an upper zone, halocline, and lower zone. The horizontal distributions of temperature of the upper zone (seasonal) for the years 1955 to 1966, and lower zone waters for the same years, excepting 1963 and 1964, off the British Columbia coast are presented. The extent of warm upper-zone waters was greatest in 1958 and 1963 and least in 1956 and 1965. Warm lower-zone waters extended furthest in 1958, 1961, and 1962, but did not retreat to the position observed in 1956. The mechanisms relating these waters to the bottom waters of the continental shelf are discussed.In the coastal and the inshore waters there is a pronounced annual cycle in the upper zone, generally with a temperature maximum and a salinity maximum in the summer. The deep water of the fjords opening directly on the Pacific is, in some cases, exchanged annually in the summer, when higher density subsurface water moves onto the continental shelf. In the fjords with indirect connection to the ocean, the deep water is exchanged irregularly at intervals of several years.
Hematological Aspects of the Thermoacclimatory Process in the Rainbow Trout,Salmo gairdneri
Authors: DeWilde Mary Anne , Houston A. H.
Published: April 2011

The blood oxygen capacity of the rainbow trout has been investigated as a function of thermal acclimation in terms of erythrocyte abundance, packed cell volume, hemoglobin concentrations, and mean erythrocytic volume and hemoglobin content. Fish at the lower acclimation temperatures employed (3, 7 C) were characterized by relatively low erythrocyte counts, hematocrits, and hemoglobin levels. Mean erythrocyte volumes tended to be relatively high, whereas mean erythrocytic hemoglobin content was somewhat below that typical of the higher temperature groups. In general, animals held at intermediate temperatures (11, 14, 17 C) showed significant increases in oxygen-carrying capacity by comparison with cold-acclimated fish. Finally trout at 21 C typically had larger numbers of somewhat smaller red cells, more hemoglobin, and higher levels of hemoglobin per erythrocyte than either the low- or intermediate-temperature fish. Significant differences were observed between summer and fall–winter series of trout, particularly with respect to hemoglobin levels. The results are discussed in relation to the general problem of respiratory thermoadaptation.
A Mathematical Model of Some Aspects of Fish Growth, Respiration, and Mortality
Authors: Ursin Erik
Published: April 2011

A simple metabolic model describing growth as the difference between what enters the body and what leaves it, is elaborated assuming that synthetic processes (the building-up, the anabolism) are consuming energy supplied by processes of decomposition (the break-down, the catabolism). This leads to partitioning total catabolism into two components, one being a function of the rate of synthesis, another keeping the body functioning independently of synthesis. The rate of synthesis is described as a function of food taken, of the efficiencies of digestion and energy conversion, and of the absorbing surface of the intestine. Catabolic processes are supposed to be functions of the oxygen concentration in the water, the absorbing surface of the gills, and the rate of oxygen transport. Both kinds of processes are made functions of temperature in the way enzymatic processes usually are. Assuming that molecular interactions accidentally go wrong makes natural mortality, like growth, a function of the rates of anabolic and catabolic processes and body size.Application of the model to data of length-at-age, food and oxygen consumption, weight loss, gill area, and natural mortality indicates that at least some of the main hypotheses cannot be rejected on available evidence.
A New Plastic-Bag Water Sampler
Authors: Anderson R. Stewart
Published: April 2011

not available
Computer vs. Manual Calculations of Temperatures and Depths
Authors: Keyte F. K.
Published: April 2011

not available
Lamprey Parasitism of Rainbow Trout in Southern Georgian Bay
Authors: Berst A. H. , Wainio A. A.
Published: April 2011

Of 2614 adult rainbow trout sampled from the Nottawasaga River of Georgian Bay during the period of 1961–67 inclusive, approximately 7.1% had one or more lamprey marks. The trout ranged in fork length from 10 to 33 inches (25 to 84 cm). However, lamprey marks were present only on fish over 16 inches (40 cm) in length. Multiple scarring was found on 30% of the trout that were marked. The incidence of marked fish reached a maximum of 17.2% in the spring of 1962, then declined to 1.3% in the fall of the same year. This decline was coincident with a reduction in the lamprey population after experimental lampricide treatment of the Nottawasaga River and adjacent lamprey spawning streams during 1960 and 1961. The incidence of marked fish remained at a relatively low level for a period of 4 years, then increased substantially, after the presumed recruitment of metamorphosed lampreys during 1966 and 1967.
Ultrasound Backscatter in Fresh and Thawed Animal Tissue
Authors: Freese M. , Makow D.
Published: April 2011

not available
Pathogenicity of Gaffkya homari for the Crab Cancer irroratus
Authors: Cornick John W. , Stewart James E.
Published: April 2011

not available
Ecology of Phytoplankton in Lake Belwood, a Storage Reservoir in Southern Ontario
Authors: Duthie Hamish C.
Published: April 2011

A 16-month study on a storage reservoir explained some of the factors controlling the seasonal development of phytoplankton in such an environment. Thermal stratification was unstable but was established in one of the two summers of the study and was associated with oxygen depletion in the hypolimnion. Both nitrate and phosphate concentrations showed distinct seasonality and the amounts in the influent were very similar to the amounts in the effluent. Large populations of Cryptomonas spp. developed in the early summer, when amounts of phosphate and nitrate were minimal, and were followed by a succession of planktonic Cyanophyta lasting into the winter. A population of Peridinium aciculiferum (Lemm.) Lemm. occurred over the winter. Based on their ecology in the reservoir the species of phytoplankton were divided into three groups: an autochthonous group, which developed populations simultaneously all over the lake; an allochthonous group, which sometimes formed populations around the inflow; and the river plankton, which rarely developed in the reservoir.
Postmortem Degradation of Glycogen and Starch in Fish Muscle
Authors: Tarr H. L. A.
Published: April 2011

Degradation of glycogen and starch in excised fish muscle blocks at 0–5 C postmortem was investigated by use of radioactive substrates. Separation of the various metabolites in the stored muscles was accomplished by perchloric acid extraction, gel filtration, treatment with anion and cation exchange resins followed by appropriate elution methods, and paper chromatography. The results showed that glycogen is degraded by both hydrolytic (anxiolytic) and phosphorolytic (Embden–Myerhof) pathways, and that starch is similarly degraded but more slowly. The degradative pattern was not significantly altered by brief blending of the muscle. Though lactate and glucose usually predominated, dextrins (or nondegraded substrate), maltose, glucose 6-phosphate, hexose diphosphate, ribose 5-phosphate, and ribose were also recovered. Though results obtained with muscle from widely different fish species were in general rather similar there were obvious quantitative differences which could possibly be attributed to a number of factors such as species differences, nutritional status, holding temperature, and state of maturation. The fact that labelled dextrins, glucose, and ribose were formed in muscle injected with radioactive lactate, suggested that all the reversible glycolytic enzymes and glycogen synthetase are functional in fish muscle blocks.
Marine Phytoplankter Fatty Acids
Authors: Ackman R. G. , Tocher C. S. , McLachlan J.
Published: April 2011

Twelve species of marine unicellular algae have been cultured under comparable conditions and the total fatty acids determined by gas–liquid chromatography. Some specific fatty acid relationships paralleling taxonomic groupings were detected but generally individual fatty acids within various algal classes showed large relative variations. The four Bacillariophyceae examined were notable for fatty acid compositions giving iodine values <150, whereas in eight other classes the iodine values were all approximately 200. It is suggested that 5,8,11,14,17-eicosapentaenoic acid, found to be a common algal longer-chain polyunsaturated fatty acid, is characteristically deposited in the lipids of filter-feeders ingesting unicellular algae.
Underwater Observations on Scallop (Placopecten magellanicus) Behaviour and Drag Efficiency
Authors: Caddy J. F.
Published: April 2011

The efficiency of an 8-ft scallop drag was estimated from population density measurements by scuba divers. Density measurements had to be made with an enclosed quadrat because of scallop swimming activity. Scallops responded to approaching objects by facing away from them and swimming. A steep rise usually preceded level swimming at a mean height of 0.4 m from bottom. Point-to-point swimming distances of up to 4 m were recorded with ground speeds in excess of 67 cm/sec. Few scallops over 100 mm could be induced to swim.Despite level bottom conditions, overall drag efficiency was low (2.1%) but increased progressively over the size range encountered (20–150 mm). Direct observations of drag function showed that swimming activity rather than selection by the drag was responsible for the low drag efficiency for the capture of scallops smaller than 100 mm.An indirect fishing mortality was established for recessed scallops buried by the drag. Dragging resulted in dislodgement of dead shell to the substrate surface, and aggregation of benthic predators in the drag tracks.
Occurrence and Significance of Iron, Manganese, and Titanium in Glacial Marine Sediments from the Estuary of the St. Lawrence River
Authors: Loring D. H. , Nota D. J. G.
Published: April 2011

In glacial marine sediments from the St. Lawrence estuary, iron varies between 1.32 and 5.42%, manganese between 0.043 and 0.28%, and titanium between 0.31 and 0.64%. The regional distributions of these elements are related to sediment texture. Analyses of individual sediment size-fractions show that Fe, Mn, and Ti concentrations generally increase with decreasing grain size. Variations in elemental ratios between the different grades suggests that not all of the Fe and Mn is located in detrital silicate minerals. Dithionite extraction of selected sediments resulted in preferential dissolution of 3–16% of the total iron, presumably that derived from amorphous and crystalline iron oxides and from sorbed material.Hydroxylamine–hydrochloride removed 5–60% of the total manganese, presumably that derived from exchangeable Mn, easily reducible Mn oxides, and sorbed Mn material. The soluble fraction is highest in freshly deposited pelites from the center of the estuary. Soluble Fe and Mn occur as oxide films on the particles deposited from suspension, and the amount held depends on rate of deposition and on the physicochemical conditions in the waters and in the sediments. In contrast, Ti occurs in detrital minerals and accumulates at the same rate as detrital sedimentary material. It is unaffected by environmental changes. This investigation shows that, despite the derivation of the sedimentary material from the Canadian Shield predominantly by nonchemical erosional processes, small but significant chemical modification of iron- and manganese-bearing material is taking place in response to present physicochemical conditions.
Increase in Aggression and in Strength of the Social Hierarchy among Juvenile Atlantic Salmon Deprived of Food
Authors: Symons Philip E. K.
Published: April 2011

Aggressive behaviour of Atlantic salmon (Salmo salar) parr, tested in groups of eight, was greater during 3 days of deprivation of food than during 3 days of feeding. Frontal and lateral displaying appeared to increase more than charging and nipping. Increased agression was only partly a result of increased locomotion, and therefore was partly a direct effect of hunger.Strong social hierarchies developed, larger fish nipping smaller ones more than the reverse. The correlation between size and hierarchical status was usually sufficient to account for the strength of hierarchy observed.Upon deprivation of food the dominant of any pair of socially unequal fish on the average increased its nipping of the subordinate. The nipping rate of dominants by subordinates did not change consistently; many low ranking fish decreased their nipping rate upon deprivation. These results would strengthen hierarchies during deprivation. Initiation of attacks by small fish, as opposed to nipping, increased consistently during deprivation.Nipping was more frequent between fish of equal status and size than between fish of unequal status or size. This could have accounted for the strength of hierarchies in groups in which the correlation between size and position was insufficient to do so.The increase in aggression upon food deprivation could function to increase the size of feeding territories when food is scarce. This and the strengthening of hierarchies would cause emigration of some fish from the area. Concentration of aggression between fish of equal size and status could permit parr of different ages to coexist.
Respiration of the Winnipeg Goldeye (Hiodon alosoides)
Authors: Hart J. S.
Published: April 2011

The respiratory metabolism of groups of goldeye was measured during rest and sustained swimming activity at 5, 10, and 15 C under conditions of continuous reduction in oxygen by the metabolism of the fish. The oxygen consumption fell progressively during swimming at all temperatures indicating dependence of metabolism on oxygen supply at all pO2 levels. During rest the oxygen consumption was relatively independent of pO2 until certain critical levels were reached. Respiration became markedly limited by CO2 in the medium when the pCO2 exceeded 50 mm Hg. It is apparent that survival possibilities of goldeye would be limited by pO2 and pCO2 between 20–40 mm Hg during the winter.
Stratification and Mixing in Coastal Waters of the Western Gulf of Maine during Summer
Authors: Hulburt Edward M.
Published: April 2011

In the summers of 1966 and 1967, very low surface temperatures, about 11 C, and weakly stratified water occurred along the western coast of the Gulf of Maine at Cape Nedick, in the Sheepscot River, and off Vinalhaven Island at the mouth of Penobscot Bay. Moderately low temperatures, about 13 C, were found often between the islands of Casco Bay. These low temperatures indicate an active vertical mixing, associated with tidal currents, that transports water warmed at the surface downward and cold water upward.Where tidal mixing is reduced, offshore from Cape Ann and in the landward confines of Casco Bay, surface temperatures over 17 C and pronounced stratification occurred. When these high temperatures were observed off Cape Ann, the weather was sunny and calm, or a light wind caused very little mixing. Within Casco Bay temperatures of 17 C or more were observed during a period when fogs were prevalent, allowing heating in clear spells in the daytime and a minimum of cooling at night.
Observations on the Greenland Shark, Somniosus microcephalus, in Northern Baffin Island
Authors: Beck B. , Mansfield A. W.
Published: April 2011

Eighteen immature Greenland sharks (Somniosus microcephalus (Bloch and Schneider) 1801) were captured during the course of a study on the biology of the narwhal, Monodon monoceros. Most had been feeding on offal resulting from the whaling operation and on fish and seal meat discarded at the campsite. Other food consumed included two egg cases of the arctic skate, Raja hyperborea, previously unrecorded from this locality. Four narwhals and one white whale were attacked in the nets, the sharks removing large chunks of skin and blubber from the carcasses.
Robustness of the DeLury Population Estimator
Authors: Braaten Duane O.
Published: April 2011

This is a study of the robustness, in estimating population size, of the usual DeLury Estimator and three modifications of it derived from the generalized exact deterministic catch equation of Beverton and Holt (1956, 1957). These estimators are called the Generalized DeLury Estimator, the Weighted Generalized DeLury Estimator, and the Effort-corrected DeLury Estimator.A computer was used to simulate varying environmental conditions, which included combinations of several vectors of catchability and effort and several types of random error. The results indicate that the generalized estimator is overall the best, at least for these simulated data. The effort-corrected estimator is just as effective, but requires effort correction. The usual DeLury estimator underestimates on the average. The weighted estimator has high variance.Catchability behavior has a marked effect on accuracy of any of these estimators. An increase in catchability from a previously constant level results in a subsequent increase in the estimate of population size. A decrease in catchability results in a decrease in the estimate. If catchability cycles, the estimate cycles with the same crest and period.Effort has little effect, at least for the vectors studied in this model.
Polyteny and Size Variation in the Copepod Pseudocalanus from Two Semi-Landlocked Fiords on Baffin Island
Authors: Woods Susan M.
Published: April 2011

Two forms of the copepod Pseudocalanus, which differ only in size, coexist in two semi-landlocked fiords on Baffin Island. The large form possesses the same number of chromosomes as the small but its chromosomes are conspicuously larger and contain about seven times as much DNA. Due to polyteny, the large form has a greater cell size and a slower development rate than the small form. The large form, having an essentially annual life cycle, matures later than the small form. Two generations of the small form may be produced in a summer with only the first reaching maturity. As the fiord waters are warmer, the small form is smaller and develops faster than its counterpart in nearby seas. The large form may represent an evolutionary attempt to restore normal arctic size and development rate in the fiords. In the cold waters of the sea, the slow development rate of the large form might lead to an excessively long life cycle, perhaps biennial. This may explain the apparent absence of the large form outside the two fiords. The polytene form may be a new species but, as the taxonomy of the genus is indefinite, a new name is deferred.
Two Modified Stains for Use in Oyster Pathology
Authors: Heaton LeRoy H. , Pauley Gilbert B.
Published: April 2011

This note describes two modified staining procedures for use in oyster pathology. One is a cresyl-fast violet stain for differentiating bacteria and fungi from tissue components in oysters. The other is a trichrome stain for collagen and bacteria in oyster tissue sections.
Three New Genera of Hemiurid Trematodes from Australian Fishes
Authors: Manter Harold W.
Published: April 2011

The following three new genera and new species of hemiurid trematodes (subfamily Lecithasterinae) are described: (1) Saturnius segmentatus from Mugil cephalus L., characterized by a peculiar internal pseudosegmentation; (2) Bilacinia australis from Naso annulatus (Quoy & Gaimard), with a pair of bilobed, postacetabular flaps; and (3) Unilacinia asymmetrica from Naso annulatus, with a single, unilateral acetabular flap.
Cytological Changes in the Pituitary Gland of the Adult Sockeye Salmon (Oncorhynchus nerka) after Gonadectomy
Authors: McBride J. R. , Overbeeke A. P. van
Published: April 2011

Effects of gonadectomy on the cytological structure of the pituitary gland of sockeye salmon were investigated. Castration of fully grown, but sexually immature, fish appeared to prevent differentiation of any periodic acid–Schiff (PAS) positive cells. On the other hand, castration of mature sockeye induced degranulation of this cell type. These cells later disintegrated. Although the acidophil cells of the proximal pars distalis in the immature castrates showed an apparent increase in number, those in the gonadectomized ripe fish exhibited marked hyperplasia and hypertrophy. In view of the "rejuvenation," including the considerable increase in body weight that occurs after castration of sexually ripe sockeye, it is thought that the changes in the acidophils noted in this experiment may reflect an increased production of growth hormone. Where the gonadectomy was incomplete it was noted that very small remnants of gonad were able to induce, or maintain, all the external secondary characteristics of full sexual maturity. The pituitary of these fish exhibited cytological features intermediate between those of the controls and the complete castrates.
Size Changes, Mortality, and Equilibrium Yields in an Exploited Stock of American Plaice (Hippoglossoides platessoides)
Authors: Powles P. M.
Published: April 2011

Records from research surveys and commercial landings for American plaice from the Magdalen Shallows, or the southwestern Gulf of St. Lawrence, showed decreases in percentage of old, large fish and in catch per unit of effort from 1955 to 1962. The changes in age composition were clearly relatable to the fishery, which was mainly by otter trawl. Ricker models indicated that wastage of deck-exposed subcommercial plaice is currently a greater mortality factor than predation by cod. Increased landings in particular years were associated with successful year-classes. Other factors affecting landings were annual differences in fleet dispersal, which were related to movements of cod, a cohabiting species. No clear decrease or increase in absolute recruitment of plaice was demonstratable because quantitative comparisons of research surveys by different vessels using different gears and with different skippers, would be misleading.Mortality estimates of adult plaice by three methods showed agreement, indicating that instantaneous rate of natural mortality was between 0.09 and 0.13. The instantaneous rate of fishing for 1957–62 was 0.46. Increasing mesh-size would reduce cod catches and have little effect in conserving plaice, but marketing small fish would increase plaice landings. Voluntary release of small plaice promptly on capture would help maintain the stock, as would reduction in numbers of large cod, the main predator of small plaice. Increased numbers of small cod since 1959, as reported by other workers, could result in greater food competition with small plaice, effectively reinforcing the ecological dominance of cod over plaice.
A Precipitin-like Reaction of the Hemolymph of the Lobster Homarus americanus
Authors: Stewart James E. , Foley Diane M.
Published: April 2011

The levels of fluorescent material in the hemolymph of lobsters injected with serum proteins from lobster hemolymph labelled with fluorescein remained relatively constant over a 6-day test period; the levels in lobsters injected with bovine serum albumin labelled with fluorescein declined rapidly. A precipitin-like reaction was observed when lobster hemolymph serum was titrated with bovine serum albumin in vitro.
Occurrences of the Little Sculpin, Myoxocephalus aeneus, in Newfoundland Waters
Authors: Ennis G. P.
Published: April 2011

Collections of the little sculpin, Myoxocephalus aeneus, in Newfoundland coastal waters during 1965–67 show that the species is much more common here than the previous records indicate. It occurs all around the island but its distribution is uneven and it appears to be more abundant on the west coast than on the east coast.
Seasonal Changes in the Limnology of Some Meromictic Lakes in Southern British Columbia
Authors: Northcote T. G. , Halsey T. G.
Published: April 2011

Seasonal changes in physical, chemical, and biological features are described in four small lakes which show different types and degrees of meromixis. There is a wide range in total dissolved solid content between lakes as well as within lakes (surface to near-bottom): Yellow, 282 (surface) to 337 (bottom); White, 6229–7918; Mahoney, 10,003–86,906; Lyons, 12,116–222,195 mg/liter, but no marked seasonal changes. In Yellow Lake meromixis is probably maintained by morphometric features of the lake basin rather than a strong chemocline; in the other lakes complete mixing is inhibited by chemical density gradients, those in Mahoney and Lyons being especially sharp.Summer, autumn, winter (under ice), and spring vertical profiles are presented for temperature, dissolved oxygen, pH, alkalinity, specific conductivity; differences within and between lakes are discussed. Other physical–chemical characteristics are given in less detail.Purple sulphur bacteria occur in three of the lakes (White, Mahoney, Lyons) and in the latter two form discrete "plates" detectable by high frequency echo sounding (confirmed by sampling). Seasonal changes in depth of the bacterial plates are considered in relation to some physical and chemical parameters. Phytoplankton, zooplankton, and benthos communities are discussed in relation to the degree of meromixis shown by the lakes.
Two Useful Devices for Vertical Plankton and Water Sampling
Authors: Schindler D. W.
Published: April 2011

Two devices for taking plankton and water samples are described. One, an inexpensive syringe sampler, will obtain small uncontaminated samples from thin strata in lakes. The other, a self-activating transparent zooplankton trap, combines many of the advantages of both net and trap-type samplers. It is capable of removing the smallest zooplankton and its light weight allows large samples to be taken easily from a small boat. Comparisons with other samplers prove the self-activating trap to be more efficient than other devices which are commonly used.
Color in Raw and Cooked Atlantic Salmon (Salmo salar)
Authors: Saito A.
Published: April 2011

Carotenoid contents in raw and cooked Atlantic salmon, and in canned Pacific salmons, were compared. The color, as measured by the Gardner color difference meter, was found to be correlated with the chromaticity coordinate x%, or with Hunter's value +a. The color of Atlantic salmon flesh, compared with that of Pacific salmon flesh (canned), is significantly redder than chum and pink salmon, but less red than coho or sockeye in terms of the carotenoid content, x% or +a values, and visual color judgment.
Growth Rate and Body Composition of Fingerling Sockeye Salmon, Oncorhynchus nerka, in relation to Temperature and Ration Size
Authors: Brett J. R. , Shelbourn J. E. , Shoop C. T.
Published: April 2011

The growth of young sockeye salmon (Oncorhynchus nerka) was studied at temperatures ranging from 1 to 24 C in relation to rations of 0, 1.5, 3, 4.5, and 6% of dry body weight per day, and at an "excess" ration. Optimum growth occurred at approximately 15 C for the two highest rations, shifting progressively to a lower temperature at each lower ration. The maximum growth rate for sockeye 5–7 months old was 2.6%/day; that for fish 7–12 months old was 1.6%/day. At 1 C a ration of 1.5%/day was sufficient to provide for a maximum growth rate of 0.23%/day. The maintenance ration was found to increase rapidly above 12 C, amounting to 2.6%/day at 20 C. No growth took place at approximately 23 C despite the presence of excess food.Isopleths for gross and net food-conversion efficiencies were calculated. A maximum gross efficiency of 25% occurred in a small area with a center at 11.5 C and a ration of 4.0%/day; a maximum net efficiency of 40% occurred within a range of 8–10 C for rations of 1.5%/day down to 0.8%/day, the maintenance level.Gross body constituents changed in response to the imposed conditions, varying in extreme from 86.9% water, 9.4% protein, and 1.0% fat for starved fish at 20 C to 71.3% water, 19.7% protein, and 7.6% fat on an excess ration at 15 C.It is concluded on the basis of growth and food-conversion efficiency that temperatures from 5 to 17 C are most favorable for young sockeye, and that a general physiological optimum occurs in the vicinity of 15 C.
Patterns of Insecticide Resistance in the Mosquitofish, Gambusia affinis
Authors: Culley Jr. Dudley D. , Ferguson Denzel E.
Published: April 2011

The extent of insecticide resistance in a resistant population of mosquitofish (Gambusia affinis) from Belzoni, Mississippi, was compared with that of a susceptible population from State College, Mississippi, using 28 insecticides of five major groups. Results of 48-hr bioassays show that resistant mosquitofish have developed high resistance only to the toxaphene–endrin related insecticides, even though insecticides from other groups were heavily applied. Spray records for the Belzoni area and insecticide characteristics such as stability and toxicity aided in evaluating cross-resistance patterns in the resistant population. Patterns of resistance in mosquitofish are similar to those in many resistant arthropods.
Seasonal Distribution, Constitution, and Abundance of Zooplankton in Lake Erie
Authors: Davis Charles C.
Published: April 2011

Zooplankton samples, collected by vertical hauls from near bottom to the surface, were obtained from 28 stations along the length of Lake Erie in October 1967. A partial similar series, confined largely to the Western Basin because of ice conditions, was collected in January 1968. The results of the analyses are tabulated as numbers of individuals per m3, and are discussed. Comparisons are made with results previously published for a comparable series of stations visited in July 1967.As in July, distinct differences were to be seen among the three major basins (Western, Central, and Eastern) in the October results. These differences are summarized. In July an expected decrease in zooplankton, such as would be predicted from lake morphology, amount of runoff from rivers, etc., occurred from west to east in the lake. In October, however, the zooplankton of the Western Basin was extremely impoverished, and the expected distribution of biomass was reversed. It is shown, on the other hand, from work done by others on samples taken from the same series of stations in October, that phytoplankton, chlorophyll a, and seston exhibited the expected distribution, emphasizing the danger of judging an ecosystem by the examination of only limited components of the community and at single periods of the year.In July the bulk of the zooplankters consisted of large cladocerans (especially daphnids) and copepods. In October there were much larger populations of rotifers and of small cladocerans (Bosmina, Chydorus). Copepods were relatively sparse. The January samples were characterized by greater numbers and a greater variety of diaptomids than in October, and the rotifers remained very important. All of the January samples contained many partially decayed microcrustaceans. This was interpreted as indicating a seasonal die-off associated with the very severe weather of the period.
Acrocirridae n.fam. (Polychaeta Sedentaria)
Authors: Banse Karl
Published: April 2011

Acrocirrus Grube and Macrochaeta Grube (Polychaeta Sedentaria), comprising at present 14 species, are removed from the Cirratulidae and placed in a new family. The descriptions of the type species of the genera and of five other species are materially improved. Acrocirrus trisectus and Macrochaeta pege are newly described; Acrocirrus heterochaetus okotensis Imajima is elevated to species rank. Diagnoses and records as well as keys for identification are given for all species of the family.
Revision of the Genus Salmincola Wilson, 1915 (Copepoda: Lernaeopodidae)
Authors: Kabata Z.
Published: April 2011

The morphology of the genus Salmincola is reviewed and its relationship to the genus Achtheres examined. Four species of Achtheres are transferred to Salmincola: A. coregonorum, A. extensus, A. strigatus, and A. corpulentus. The taxonomy of the genus is based on new and more reliable criteria, mainly on the details of the appendages. The structure of the second antenna and of the maxilliped, as well as the type of the bulla, are regarded as best recognition marks. All species of Salmincola are redescribed with these criteria in mind and the genus is recognized as having 15 species. A key to the species is given.The genus is divided into two subgenera. Subgenus Salmincola (Salmincola) is parasitic mainly on Salmonidae and is distinguished by the well-developed claw of the maxilliped. Subgenus Salmincola (Brevibrachia) is parasitic exclusively on Coregonidae and is distinguished by the vestigial claw of the maxilliped.Species of Salmincola fall into one of three categories: circumpolar, continental, and bicontinental. The first category comprises five species: S. carpionis, S. edwardsii (parasites of Salvelinus), S. thymalli (parasite of Thymallus), S. extensus, and S. extumescens (parasites of the coregonids). The continental species are subdivided into Palearctic and Nearctic. There are seven Palearctic species: S. coregonorum, S. stellatus, S. lotae, S. cottidarum, S. nordmanni, S. strigatus, and S. jacuticus. Only one Nearctic species is known, S. siscowet. Two species are bicontinental: S. salmoneus has a distribution straddling the Atlantic Ocean and S. californiensis is a Pacific species, found in North America and Asia.
Evaluation of Lamprey Larvicides in the Big Garlic River and Saux Head Lake
Authors: Manion Patrick J.
Published: April 2011

Bayluscide (5,2′-dichloro-4′-nitrosalicylanilide) and TFM (3-trifluoromethyl-4-nitrophenol) were evaluated as selective larvicides for control of the sea lamprey, Petromyzon marinus, in the Big Garlic River and Saux Head Lake in Marquette County, Michigan. Population estimates and movement of ammocetes were determined from the recapture of marked ammocetes released before chemical treatment. In 1966 the estimated population of 3136 ammocetes off the stream mouth in Saux Head Lake was reduced 89% by treatment with granular Bayluscide; this percentage was supported by a population estimate of 120 ammocetes in 1967, an indicated reduction of 96% from 1966. Post-marking movement of ammocetes was greater upstream than downstream.
Effect of Feeding and of DDT on the Activity of Hepatic Glucose 6-Phosphate Dehydrogenase in Two Salmonids
Authors: Buhler Donald R. , Benville P.
Published: April 2011

The specific activity of liver glucose 6-phosphate dehydrogenase in yearling rainbow trout remained unchanged when the fish were starved for periods as long as 8 weeks and when starved animals were fed diets of various compositions. Injection of insulin concurrently with refeeding also failed to alter the specific activity of the enzyme in trout. The absence of a dietary or insulin influence on the teleost enzyme system is to be contrasted with studies in mammals in which the activity of hepatic glucose 6-P dehydrogenase was markedly stimulated after refeeding starved animals or injection of insulin.Ingestion of the pesticide DDT by juvenile coho salmon or adult rainbow trout also had no effect on the specific activity of liver glucose 6-P dehydrogenase and DDT failed to inhibit the rainbow trout enzyme in vitro. These results also differ considerably from those found in higher animals.These results suggest that the glucose 6-P dehydrogenase enzyme in teleosts may be under a different type of regulatory control from that found in mammals.
Alterations in the Electrophoretic Protein Patterns of Refrigerated Fish
Authors: Moore G. S. , Peters H. A. , Levin R. E.
Published: April 2011

Expressible fluid was obtained from fillets on the 1st, 4th, and 14th days of refrigeration. The protein concentration was determined and electrophoresis using cellulose polyacetate strips was performed on each sample. The protein concentration remained constant between 6 and 8 g/100 ml over the 2-week period. Qualitative and quantitative examination of the densitometry tracings revealed that protein(s) having specific migratory characteristics were strongly associated with the duration of storage at 2 C.
Hermaphroditism in a Pacific Hake, Merluccius productus, from Puget Sound, Washington
Authors: Millikan Alan E. , Pattie Bradley H.
Published: April 2011

An hermaphroditic Pacific hake is reported encountered during a routine biological examination of over 12,000 individuals. The normal right ovary was accompanied by the left ovotestis. The size and age of the fish suggests this condition did not adversely affect growth.
Electrophoretic Variants of L-Alpha-Glycerophosphate Dehydrogenase in Pacific Ocean Perch (Sebastodes alutus)
Authors: Johnson A. G. , Utter F. M. , Hodgins H. O.
Published: April 2011

Three phenotypes of L-alpha-glycerophosphate dehydrogenase (α-GPDH) were found in muscle extracts of Pacific ocean perch by starch-gel electrophoresis. No association was obvious between alpha-glycerophosphate phenotype and sex or stage of maturity. The observed phenotypes were presumed to be under the control of two allelic genes, F and S. This assumption was supported by the distribution of phenotypes of fish collected off the coasts of Washington and Oregon. This report is the first on genetic variants of an enzyme in Pacific ocean perch and suggests that isozymes of α-GPDH may be useful in population studies of this species.
Population Dynamics of F1 Splake (Salvelinus fontinalis × S. namaycush) in Lake Huron
Authors: Berst A. H. , Spangler G. R.
Published: April 2011

Ninety-eight percent of 5391 F1 splake recovered from a 1966 planting of 49,000 yearlings in Burnt Island Bay (45°50′N, 82°57′W) on the south shore of Manitoulin Island were taken within 32 km (20 miles) of the planting site. Remaining recaptures were made at distances up to 322 km (200 miles).Growth rates of the hybrids in Lake Huron exceeded those reported for native and planted lake trout. A commercial size of 0.9 kg (2 lb) round weight was attained by the fall of their 2nd year in the lake. The splake grew rapidly through the winter months. Yearlings fed mainly on invertebrates and 2- to 4-year-olds fed almost entirely on fish.Eight percent of 3054 hybrids examined had one or more lamprey marks. Fish less than 30 cm (12 inches) bore no evidence of lamprey attack; larger hybrids showed frequencies of lamprey marks increasing from 5.4% for 30- to 40-cm fish to 11.6% for those larger than 40 cm. The incidence of fresh lamprey marks was minimal in spring and early summer and reached a peak in September when more than 20% of the specimens bore fresh marks.Of the 2- and 3-year-old splake recovered, 50 and 40%, respectively, were males. The onset of sexual maturity in both sexes occurred at age II. By age III, 86% of the males and 58% of the females were mature. Ripe 3-year-old hybrids of both sexes were captured over former lake trout spawning grounds. Fecundity of 3-year-old females averaged 2512 eggs. Although survival to age IV was low, a substantial number of the hybrids attained sexual maturity.A total of 8.4% of the planting of 49,000 yearling hybrids was reported taken by sport and commercial fisheries during a 3-year period.
Evaluation of the Miller High-Speed Sampler for Sampling Yellow Perch and Walleye Fry
Authors: Noble Richard L.
Published: April 2011

Evaluation of avoidance of Miller samplers towed at 8 mph indicated that avoidance began when yellow perch fry were less than 8 mm long and increased as fry grew larger. Catches were increased by increasing towing speed to 11 mph, by using an electric shocking grid in front of the sampler, by using clear and translucent rather than dark, opaque samplers, and by night sampling. A sampler with an aperture 1.5 times as large as the conventional Miller sampler was not more effective. Avoidance by walleye fry occurred, but was less well defined. Application of the results to the development of sampling techniques is discussed.
Stream Habitat Utilization by Cohabiting Underyearlings of Chinook (Oncorhynchus tshawytscha) and Coho (O. kisutch) Salmon in the Big Qualicum River, British Columbia
Authors: Lister D. B. , Genoe H. S.
Published: April 2011

Habitat distributions of chinook and coho salmon underyearlings in the Big Qualicum River, Vancouver Island, B.C., under controlled flow conditions indicated that at similar sizes their habitat requirements during the first 3 months of stream life were similar. Just after emergence, fry of both species occupied marginal areas in association with bank cover. With increased size, the young fish moved into habitat of progressively higher velocity. However, differences between the species in time of emergence and size evidently resulted in a high degree of spatial segregation. Chinook fry emerged about a month earlier than coho, were larger upon emergence, and grew at a faster rate. Apparently, because of their larger size at a given time, chinook preferred higher velocity locations than coho.
Evaluation of Opercular Catheterization as a Method for Sampling Water Expired by Fish
Authors: Davis John C. , Watters Kenneth
Published: April 2011

Experiments were carried out on rainbow trout to see if cannulae implanted at different positions on the operculum yield accurate estimates of mean expired oxygen tension. This value is frequently used to calculate utilization or ventilation volume in fish and should therefore be accurately determined.Opercular oxygen tension [Formula: see text] recorded from seven quiescent fish (383–426 g, 10–12 C) in aquaria was highly variable with respect to time and cannula placement. Expired [Formula: see text] recorded from cannulae placed in the middle, upper, or lower part of the posterior margin of the operculum ranged from 54 to 157 mm Hg and was sometimes identical with inspired [Formula: see text]. When the fish were chased, expired oxygen tension usually rose but the magnitude of the rise and its duration were not uniform from cannula placement to placement. Other studies, on 21 trout (217–388 g, 10–12.5 C) whose gills were perfused with water at different flow rates with a mouth tube, indicated that the [Formula: see text] variability existed over a wide range of perfusion rates. In addition, [Formula: see text] levels from all three placements at perfusion rates approximating those of normal ventilation were frequently below the mean expired oxygen tension calculated from oxygen uptake and gill water-flow rate data.It is concluded that opercular cannulae provide poor estimates of mean expired oxygen tension in trout. The use of this technique to determine mean [Formula: see text] could lead to serious errors. It appears that large changes in oxygen utilization can be detected with opercular cannulae but any utilization values determined in this way would likely be erroneous.
Standing Stocks and Other Features of Eelgrass (Zostera marina) Populations on the Coast of Alaska
Authors: McRoy C. Peter
Published: April 2011

Of eelgrass populations sampled from southeast Alaska to Bering Strait, those in Kinzarof and Izembek lagoons on the Alaska Peninsula had the highest standing stocks (mean, 1510 g dry wt/m2) and that in Calder Bay in southeast Alaska had the lowest (65 g dry wt/m2). Caloric content of eelgrass averaged 4211 cal/g in the leaves and 3571 cal/g in the roots and rhizomes. The concentration of chlorophyll a in eelgrass had a mean of 0.513 mg/g fresh wt, with one exception. Population densities were high in Kinzarof and Izembek lagoons (mean, 4576 turions/m2) and low in all other sample areas (599 turions/m2). Flowering plants were 3–4% of the total population. Mean leaf length varied from 13 to 48 cm and width from 2.4 to 5.1 mm. The differences in the eelgrass populations appeared to be related to local conditions rather than a large geographical gradient.
A Technique for Marking Small Fish with Injected Fluorescent Dyes
Authors: Smith R. J. F.
Published: April 2011

Individual fish or small groups of fish can be marked by injecting small amounts of fluorescent dye under the skin. This method caused no apparent injury to stickleback or to a fathead minnow. The marks produced were still visible after 8–11 months.
Taste Responses in Atlantic Salmon (Salmo salar) Parr
Authors: Sutterlin A. M. , Sutterlin N.
Published: April 2011

External receptors located in the snout region of Atlantic salmon parr are innervated by the facial nerve and are differentially sensitive to several chloride salts (NaCl = KCl > MgCl2 > CaCl2). They are also sensitive to mineral and organic acids but insensitive to uncharged molecules such as neutral amino acids and simple sugars.The palatine organ containing taste buds situated on the roof of the mouth is sensitive to strongly ionized as well as uncharged molecules.The two classes of receptors differ in temporal patterns of discharge and in their susceptibility to the blocking agents Hg++ and Pb++ and the potentiating agent Cu++.Salmon parr can detect Hg++ in concentrations lower than other divalent cations as judged electrophysiologically; food pellets treated with dilute solutions of Hg++ are rejected by the fish.As chain length increases in the aliphatic acid series the compounds become increasingly stimulatory as measured by nerve discharges in the palatine nerve.Inert carriers treated with aliphatic acids of increasing chain length become increasingly preferred by salmon, and carriers treated with valeric and caproic acid are ingested.Anosmic fish are capable of discriminating chemically treated carriers in a way similar to fish in which the olfactory organ is intact.The cellular nature of external receptors of the snout is uncertain; the possibility that they are neuromasts is discussed.
Defecation Rate of Three Tubificid Oligochaetes Found in the Sediment of Toronto Harbour, Ontario
Authors: Appleby A. G. , Brinkhurst R. O.
Published: April 2011

The defecation rate of three tubificids is affected by temperature but the effect differs from species to species. Information on defecation rate and weight change at each experimental temperature suggests an optimum temperature range of 14 C for Peloscolex multisetosus, 18 C for Tubifex tubifex, and greater than 20 C for Limnodrilus hoffmeisteri. Downward trends of defecation rate with time were recorded for P. multisetosus, but these were probably due to lowered activity prior to the observed mortality. Upward trends in defecation rate with time in L. hoffmeisteri may indicate continuing acclimation to experimental conditions beyond their 10- to 14-day duration, or a need to process increasing amounts of less nutritious mud because of selective feeding on the richer fractions at the beginning of the assay period. Data on the relative abundance and distribution of species in Toronto Harbour is used to estimate defecation rates of the tubificid populations in the field.
Taxonomic Status of Calanus finmarchicus and C. glacialis (Copepoda), with Special Reference to Adult Males
Authors: Frost Bruce W.
Published: April 2011

A morphometric analysis using certain taxonomic characters of adult males of Calanus finmarchicus (Gunnerus) and C. glacialis Jaschnov shows that the taxa comprise two non-overlapping clusters. Calanus finmarchicus and C. glacialis are probably reproductively isolated. Differences between the species in geographical distribution, vertical distribution, and timing of life cycles also support this conclusion. Previous taxonomic studies of adult females of the two species have yielded inconclusive results, probably because the analyses were based largely on subgeneric characters.