bluuebunny/crossref_metadata_2025 huggingface dataset:
Life Span, Maturation, and Growth of Two Hemiurid Trematodes, Tubulovesicula lindbergi and Lecithaster gibbosus, in Pacific Salmon (Genus Oncorhynchus)
Authors: Margolis L. , Boyce N. P.
Published: April 2011

Studies on the life span, maturation, and growth of two trematodes of the family Hemiuridae were based on periodic sampling of two captive stocks of naturally infected pink and chum salmon. The fish were caught during their 1st month at sea and maintained in filtered sea water to preclude further infection.Tubulovesicula lindbergi (Layman) was found to mature in 2–4 months and live at least 31 months, growing during that time from about 0.6 mm to more than 4.5 mm; Lecithaster gibbosus (Rudolphi) matured in 1–2 weeks and had a life span of about 2–9 months, growing from 0.5 mm to almost 1.9 mm. There was considerable variation in growth rate within each species. Among specimens of L. gibbosus faster growth apparently was associated with a shorter life span. Retardation of growth and maturation at high intensities of T. lindbergi infection is suggested.Evidence is presented in support of the view that the experimental results are applicable to the course of these infections in nature.
Pomphorhynchus laevis (Zoega) Müller, 1776 (Acanthocephala) in Atlantic Salmon (Salmo salar) and Its Use as a Biological Tag
Authors: Pippy John H. C.
Published: April 2011

Pomphorhynchus laevis (Zoega) Müller, 1776, an acanthocephalan, occurred in 25.4% of 974 juvenile Atlantic salmon (Salmo salar) from 18 drainage systems in the British Isles and was absent in 1063 juvenile salmon from 36 systems in North America. Its incidence in Irish smolts was about 25 times that in Scotland, England, and Wales. A comparison of its distribution with that of potential intermediate hosts in the British Isles suggests that the amphipod Gammarus duebeni is the intermediate host in Ireland and Gammarus pulex pulex in Scotland, England, and Wales. Pomphorhynchus laevis seems to be useful for indicating the tributary of origin of salmon smolts in several Irish rivers. Its usefulness as a tag for Irish salmon on the high seas is not yet established.
Moulting in a Parasitic Nematode, Phocanema decipiens. V. Timing of Feeding During the Moulting Cycle
Authors: Davey K. G.
Published: April 2011

The use of marker dyes in the culture medium reveals that feeding behaviour in Phocanema cultured in vitro is restricted to two periods during the moulting cycle. One is short-lived and occurs after about 24 hr in culture, after the new cuticle has begun to form. There is no evidence of feeding between 36 and 96 hr in culture. The significance of this discontinuous feeding behaviour is discussed, particularly in the light of volume changes which can be expected to occur during the moulting cycle.
A New Acanthocephalan, Acanthosentis cameroni n.sp., from the Intestine of a Freshwater Fish, Rohtee cotio Skyes, 1839, from Lucknow
Authors: Gupta S. P. , Kajaji Vijay Laxmi
Published: April 2011

Acanthosentis cameroni n.sp. is described from the intestine of a freshwater fish Rohtee cotio Skyes,. 1839 (= Osteobrama cotio Heckel, 1843), from Lucknow. The systematic position of Acanthosentis Verna and Datta, 1929, is discussed and a key to the species of this genus is given. Acanthosentis betwai Tripathi, 1956, is considered a synonym of A. antespinus Verma and Datta, 1929.
Biology of Bothrimonus (= Diplocotyle) (Pseudophyllidea: Cestoda) Part I. History, Description, Synonymy, and Systematics
Authors: Burt M. D. B. , Sandeman I. M.
Published: April 2011

Bothrimonus (= Diplocotyle) is described from six species of teleost fishes and three species of gammarids from various geographical locations: Apeltes quadroons from Newfoundland; Microgadus tomcod from Massachusetts; Oncorhynchus gorbuscha from Attu Island in the Pacific Ocean; Pseudopleuronectes americanus from St. Andrews, New Brunswick; Salvelinus alpinus from Greenland; Salmo salar from Newfoundland; Gammarus océaniens from Newfoundland; Marinogammarus finmarchicus and M. pirloti from St. Andrews, Scotland. The synonymy and morphological variation of Bothrimonus is discussed and all the material examined is considered to be B. sturionis Duvernoy, 1842.
A Comparison of Speciation in Diclidophorinean Monogenean Gill Parasites and in Their Fish Hosts
Authors: Llewellyn J. , Tully Christine M.
Published: April 2011

Twelve species of monogenean gill parasites belonging to the subfamily Diclidophorinae and species-specific to mainly gadid fish hosts have been compared with each other, and their taxonomic interrelationships assessed. A comparison of the resulting classification with that of Svetovidov's of the hosts has shown a considerable degree of correspondence between, and hence of mutual support for, the two independently derived classifications. However, since a very substantial majority of gadid species do not have monogenean gill parasites, the usefulness of a classification of these parasites in elucidating taxonomic problems of the hosts is correspondingly limited.
Marine Fish Haematozoa from New Brunswick and New England
Authors: Laird Marshall , Bullock Wilbur L.
Published: April 2011

Of 1142 fish (68 species) examined, 140 (21 species) yielded blood parasites. Overall incidence was much higher at St. Andrews, N.B., than at Woods Hole, Mass., as was the variety of fish harbouring haematozoa — 15 species (46.9%) in the former case, but only 4 (9.3%) in the latter.Trypanosoma rajae Laveran and Mesnil and Cryptobia bullocki Strout are new records for Canada, Haemogregarina delagei Laveran and Mesnil has not previously been reported from the western side of the Atlantic, and the present finding of an undesignated species of Haemohormidium Henry (a babesioid genus with which Babesiosoma Jakowska and Nigrelli is now synonymized) is the first from North American marine fish. New hosts and localities are listed for Haemogregarina bigemina Laveran and Mesnil, H. platessae Lebailly, H. aeglefini Henry, H. myoxocephali Fantham et al., and certain unidentified haemogregarines. Haemogregarina urophysis Fantham et al. is relegated to synonymy with H. aeglefini; and H. gadi pollachii Henry and H. pollachii Henry are discarded as nomina nuda. Myxosporidians of the genus Kudoa are reported (presumably as contaminants derived from slit muscle) in blood films from six hosts.Haemogregarina mavori n.sp., from Passamaquoddy Bay Macrozoarces americanus, averages 6.4 × 2.9 μ. Broadly oval to reniform and with a large, subterminal nucleus, it is found in erythrocytes that are shorter and broader than normal and exhibit marked nuclear displacement.Piscine erythrocytic necrosis (PEN) is a degenerative infection responsible for massive red blood cell destruction in Gadus morhua (Passamaquoddy Bay) and also found in Liparis atlanticus (Kent Island, N.B.) and Myoxocephalus octodecemspinosus (Portsmouth Harbor, N.H.). A distinctive inclusion body formed in the cytoplasm of infected red cells recalls similar bodies associated with Pirhemocyton Chatton and Blanc and Toddia França. Erythrocyte nuclei disintegrate with the liberation of viruslike particles formed in vesicles within them.
UV-Absorbing and UV-Fluorescing Substances in the Belly Skin of Fry of Coho Salmon (Oncorhynchus kisutch)
Authors: Lee Agnes S. K. , Vanstone William E. , Markert John R. , Antia Naval J.
Published: April 2011

The belly skin of 4-month-old coho salmon fry was extracted with 0.5 M NH4OH, and the extract was analyzed by paper chromatography for UV-absorbing and UV-fluorescing substances. Six fluorescing and three absorbing substances were isolated and characterized by Rfvalues, UV-absorption spectra, and chemical reactions, and were identified with known compounds where possible. The three UV-absorbing substances were identified as guanine, hypoxanthine, and inosine monophosphate. Three of the UV-fluorescing substances were identified as ichthyopterin, pterin 6-carboxylic acid, and 7,8-dihydroxanthopterin. A fourth fluorescing substance appeared to be an artefact produced by the action of NH4OH on ichthyopterin. The remaining two fluorescing substances appeared to be unknown glycosides, presumably isomers, both containing glucose, xylose, and mannose.
A New Species of Acantholiparis (Pisces: Liparidae) from the Eastern Subarctic Pacific Region, with Distribution Notes for the Genus
Authors: Grinols Richard B.
Published: April 2011

Acantholiparis caecus is described for the first time and reported to occur off the northern Oregon coast. The range of its congener, A. opercularis, is extended south off Newport, Oregon.
Effect of Finclipping on Survival of Sockeye Salmon (Oncorhynchus nerka)
Authors: Weber Douglas , Wahle Roy J.
Published: April 2011

A finclip and a chemical (tetracycline) mark were applied, in similar numbers, to hatchery-reared fingerling sockeye salmon (Oncorhynchus nerka). In mark-sampling of returning adults 3 and 4 years after release from the hatchery, numerical comparison of fish with the two marks showed that fewer finclipped fish returned than expected. It was demonstrated that the tetracycline mark did not affect survival and that the difference between returns of fish with the two marks originated in mortality caused by finclipping. The mortality attributed to finclipping was estimated as 39%.
Some Properties of the Fluorescence of Fish Muscle
Authors: Manohar S. V.
Published: April 2011

White muscle of a fish in prerigor condition fluoresces when irradiated with ultraviolet light of 366 mμ. Investigations carried out with the white sucker (Catostomus commersoni) indicate that the fluorescence is destroyed by treating the muscle with dilute acids. Emission spectra of fluorescence show a peak at about 460 mμ. Prerigor muscle also reduces a tetrazolium salt (Nitro BT) to its colored formazan. From these observations it is suggested that reduced pyridine nucleotides are at least partly responsible for the fluorescence of prerigor muscle.
Extensions of the Known Northern Range Limits of Ocean Whitefish, Caulolatilus princeps, and California Halibut, Paralichthys californicus
Authors: Pattie B. H. , Baker C. S.
Published: April 2011

The known northern range limit of Caulolatilus princeps Jenyns is extended some 120 nautical miles further north and that of Paralichthys californicus Ayres nearly 100 miles further northwest.
Use of Spinner Culture Cells to Detect Water Pollution
Authors: Li M. F. , Jordan Carol
Published: April 2011

The sensitivity of L-cells (spinner culture) to several pesticides and a herbicide was determined. The inhibition of L-cells growth was marked and in the case of DDT was shown to be strictly concentration-dependent. The simplicity and reproducibility of the assay system should make it a useful tool in water pollution studies.
Characteristics ofGaffkya homari, the Causative Agent of the Lobster Disease Gaffkemia
Authors: Stewart James E. , Foley Diane M. , Ackman R. G.
Published: April 2011

Gaffkya homari did not exhibit lipase, protease, or lecithinase exoenzyme activities. The organism was coagulase and fibrinolysin negative; only lactic acid was produced from glucose. The capacity of whole lobster hemolymph or its components to promote the growth of G. homari was assessed.
The Community Concept in Marine Zoology, with Comments on Continua and Instability in Some Marine Communities: A Review
Authors: Mills Eric L.
Published: April 2011

The community concept has had a long, complex history in plant and animal ecology. Divergent views about the nature of communities have been most marked in plant ecology: the Zurich–Montpellier school regarded plant communities as largely abstract, based on a mosaic of vegetation, whereas the Uppsala school and other northern plant ecologists regarded communities as concrete, quantifiable units. The analogy between communities and organisms has been used often, particularly in American dynamic ecology, although the analogy can only be a loose one. Communities have also been regarded as abstractions from independent continuous distributions of the individual species. This idea has been used in recent gradient analysis of plant communities.Similar and equally variant ideas have been used in marine zoology. Many studies in marine ecology have been based on Möbius' concept of the biocoenosis, or on Petersen's use of dominant or conspicuous index species, with added theoretical notions which apparently originated in plant ecology. New evidence is presented that some marine benthic communities may be characterized in terms of dominants while also allowing analysis as parts of continua of distribution along gradients. In addition, although stability usually increases as communities evolve, some types are intrinsically unstable because of the activities of the organisms themselves, rather than because of changes in the physical environment alone.Because there are different kinds of marine "communities" a single rigorous definition seems impossible. A definition is proposed which avoids theoretical suppositions about community dynamics to allow the variety of phenomena in community relations to be investigated in a relatively unbiased way.
Distinctive Aspects of the Ecology of Stream Fishes: A Review
Authors: Allen K. Radway
Published: April 2011

The essential feature of a stream is the continuous flow of water, and the various schemes of classification of streams and the associated fish fauna are largely based on factors which determine the average velocity. These schemes have been better developed in Europe than elsewhere, probably due to the relative uniformity of the climate. The characteristic features of fish inhabiting the more rapid streams can be related to the constraints imposed by this environment, and particularly by the need for the population to maintain its position against the continuous tendency of the stream to transport it downstream. Physiological factors associated with the normally high oxygen level and the need for continuous activity include a high routine metabolic rate, a high oxygen threshold for full activity, and, possibly, a high lower lethal limit for dissolved oxygen. Adult fish maintain their position either by continuous swimming in midwater, and these usually have a streamlined shape which is circular or laterally compressed in cross-section, or by avoiding the current and living closely attached to or in the substrate and these are usually dorso-ventrally depressed. The eggs are usually protected from the current by burying them in the substrate, sometimes in a well-developed nest. The general absence of vegetation in rapid streams results in the fish generally feeding principally on the available animal food, usually small invertebrates taken either in the drift or off the bottom. The solitary territorial behaviour which characterizes most stream-living fish probably leads to more even distribution and more efficient utilization of the food supply.
Quantitative Comparison of Peritoneal Washes and Feces for Detecting Infectious Pancreatic Necrosis (IPN) Virus in Carrier Brook Trout
Authors: Billi James L. , Wolf Ken
Published: April 2011

Paired fecal samples and peritoneal washes were taken from 300 18-month-old brook trout for determining their relative value in detecting IPN virus. The testing of feces revealed 14 times as many carriers as were found by peritoneal washes. Initial examinations showed at least 63% of the fish to be carriers of the virus, but 30% more were detected in four additional tests. Fecal output of virus from 37 fish was quantified up to five times during a period of 7 months which included the spawning season. Although there were exceptions, fish with high outputs of virus tended to maintain that level, and low titer carriers tended to yield small amounts, and in some instances, no virus. Tests of fecal extracts which were pooled from 5, 10, and 15 fish showed that virus was readily detected in all three. For economy and efficiency, the use of 10- or 15-sample pools is recommended for determining the presence of IPN in fish.
Overwinter Survival of Wild Fingerling Brook Trout in Lawrence Creek, Wisconsin
Authors: Hunt Robert L.
Published: April 2011

Overwinter survival of brook trout (Salvelinus fontinalis) from the 9-month-old fingerling stage to the 16-month-old yearling stage varied from 35 to 73% during 11 successive winters (1954–65). Mean survival through these first winters of life was 54%.Survival appeared to be independent of fingerling density most winters, and especially when September densities were less than 2200/km, as they were during 7 of 11 years. Overwinter survival tended to increase with an increase in mean length of fingerling stocks (r = 0.83++) and with an increase in winter water temperatures. Intraspecific predation did not appear to be a critical mortality factor. The survival advantage of increased fingerling size was probably related to increased physiological resistance to temperature-associated stresses rather than reduced vulnerability to predation.
Primary Production and Nutrients in Ogac Lake, a Landlocked Fiord on Baffin Island
Authors: McLaren Ian A.
Published: April 2011

Primary production was about 12 g/m2 in the middle basin of Ogac Lake during 1962. Production was limited by available N, probably largely by amount of nitrate available at the end of winter. Production was largely concentrated in narrow strata — one descending from near the surface in June to occupy nutrient-rich deep water in summer, and another developing at the halocline in summer, possibly sustained by nutrients from freshwater kill of the littoral biota in 1962.Polyethylene columns, 1 m in diameter and 30.5 m long, were set between the fresh surface and anoxic depth of the middle basin in 1962. A four-fold increase of nitrate and a two and a half-fold increase of phosphate led to a parallel uptake of the two nutrients in the columns, and to an approximately five-fold increase in mean amount of chlorophyll and a seven-fold increase in primary production compared with the lake during the period of the fertilization experiment.
Free Fatty Acids of Herring Oils: Possible Derivation from both Phospholipids and Triglycerides in Fresh Herring
Authors: Addison R. F. , Ackman R. G. , Hingley J.
Published: April 2011

The free fatty acids (FFA) of nine commercially produced Nova Scotia herring oils were compared with the overall oil fatty acid compositions. Results were consistent with the FFA having arisen primarily through hydrolysis of phospholipids, but additionally from hydrolysis of triglycerides. Phosphorus levels indicate that hydrolysis of phospholipids probably occurs by enzyme action, before oil production rather than after, but suggest that in some instances FFA may be formed by slow chemical hydrolysis of phospholipids after oil production.
Differences Between Two Populations of Landlocked Atlantic Salmon (Salmo salar) in Newfoundland
Authors: Leggett William C. , Power G.
Published: April 2011

Differences in growth rates, longevity, fecundity, and time of spawning between two populations of landlocked Atlantic salmon (Salmo salar) in Newfoundland were attributed to food quality and quantity. Salmon in Flatwater Pond, an oligotrophic lake with a poor invertebrate population and no forage fish, grew slowly (145 mm at age 2+, 245 mm at age 5+), suffered high mortality (approximately 60% in males after age 2+ and in females after age 3+), had very low fecundity (an average of 153 eggs per female), and were sexually mature by late August. Salmon in Gambo Pond, an oligotrophic lake with a good invertebrate population and an ample forage fish population in the form of Gasterosteus aculeatus, grew more rapidly reaching 157 mm at age 2+, 367 mm by age 5+, and 437 mm by age 8+. Longevity of the Gambo Pond stock was greater than that of Flatwater Pond (39.6% of the Gambo sample were older than 4+ years compared with 3.2% for Flatwater Pond). Gambo Pond salmon are not sexually mature until October.Salmon in both lakes exhibited seasonal movement into deeper water when the surface warmed above 14 C. At Flatwater Pond this movement contributed to an early end to the growing season.Scale reading was found to be an unreliable method for determining past spawning activity. Spawning marks were found on only 1 of 17 females known to have spawned previously.
Nucleotide Degradation in Frozen Swordfish Muscle
Authors: Dyer W. J. , Hiltz Doris I.
Published: April 2011

In frozen swordfish steaks, inosine monophosphate (IMP) dephosphorylation was active at − 8 C and less so at − 18 C. A loss of IMP at − 26 C became apparent during a 2-year storage period. Rates of loss were about 0.24 and 0.029 μmoles per g per week at − 8 and − 18 C, the Arrhenius plot being linear over the temperature range 0 to − 26 C. Inosine ribohydrolase was less active; nevertheless, about 2.5 μmoles per g of hypoxanthine accumulated in 2 years at − 8 C. Taste panel tests indicated a storage life of 3 months at − 8 C, 9 months at − 18 C, and several years at − 26 C. The loss of IMP was slightly slower than the associated taste panel score decrease and thus may have potential as an indicator of frozen storage quality in some fish species, though it did not prove useful for swordfish. Hypoxanthine formation at low storage temperatures is sufficiently slow to allow use of hypoxanthine as an index of prefreezing quality; however, red muscle must not be included in the sample because of its high initial hypoxanthine content, about 1.9 μmoles per g.
Reduction of Zooplankton Standing Stocks by Predaceous Cyclops bicuspidatus thomasi in Marion Lake, British Columbia
Authors: McQueen Donald J.
Published: April 2011

The standing stock of the copepod Cyclops bicuspidatus thomasi Forbes in Marion Lake, B.C., was observed during the summers of 1966 and 1967. Stage IV copepodids excysted during April and moulted to adults, which produced eggs in May. The new generation developed to the copepodid IV stage by midsummer, when about 85% of the animals moved to the bottom and encysted. The copepodids of stage IV and V and the adults are predators. When each group of the prey of C. b. thomasi was offered separately in the laboratory, these predators fed best on their own nauplii and copepodids, diaptomid nauplii, and rotifers, but ate few diaptomid copepodids and cladocerans. When offered a mixture of prey at the lake, the predators ate nauplii in the same quantities as in the laboratory but, contrary to the laboratory results, very few rotifers. During the summer of 1967 C. b. thomasi copepodids IV and V and adults were estimated to have eaten 31.0% of the C. b. thomasi nauplius standing stock, and 30.2% of the diaptomid nauplius standing stock.
Growth of Juvenile Chum Salmon (Oncorhynchus keta) Under Different Feeding Regimes
Authors: LeBrasseur R. J.
Published: April 2011

Juvenile chum salmon were fed on six different concentrations of size-selected zooplankton for 8 weeks. Zooplankton were caught daily and sorted through sieves into size-groups roughly as follows: 6–20 mm total length, mainly euphausiids; 2.5–4.5 mm, mainly copepods; and ≤ 1.5 mm, mainly small copepods. The rate of growth in weight of the fish was found to be dependent upon the concentration of the ration. Fish which were offered no food lost weight, and fish which were offered excess food increased in weight by 5.4% per day. The mean growth rate of the fish held on fixed rations ranged from 2.2 to 5.7% per day and was found to be independent of the type of prey. Electivity experiments showed that all the fish selected copepods 1.6–4.5 mm long in proportion to their abundance and rejected copepods ≤ 1.5 mm. The euphausiids were selected only by fish which had previously fed on euphausiids. The effect of variations in the availability of prey is discussed.
Sustained Swimming Ability of Larvae of Walleye (Stizostedion vitreum vitreum) and Yellow Perch (Perca flavescens)
Authors: Houde Edward D.
Published: April 2011

Sustained swimming ability of limnetic larvae of walleye and yellow perch from Oneida Lake, New York, was compared in an experimental apparatus. The current velocity that 50% of the larvae could sustain in 1-hr tests was recorded for each 1-mm length class. Yellow perch larvae swam better than walleye larvae for length classes less than 9–10 mm total length (TL), but swimming ability of the two species was equal for length classes from 9 to 15 mm. Velocities that larvae under 9.5 mm TL could sustain were less than 3.0 cm/sec, and it was concluded that newly hatched young of both species would be subject to transport by lake currents of greater velocity. Relative swimming ability, expressed as the number of body lengths/sec that a larva could sustain for 1 hr, approached an asymptote between 3 and 4 lengths/sec for larvae longer than 9.5 mm. The greater swimming ability of newly hatched yellow perch larvae, compared with that of walleyes, appeared to be related to the smaller yolk sac of yellow perch at hatching.
Aggregations of Spottail Shiners and Yellow Perch
Authors: Nursall J. R. , Pinsent Morley E.
Published: April 2011

Spottail shiners (Notropis hudsonius (Clinton)) and immature yellow perch (Perca fluviatilis Linnaeus), ranging in size from 30 to 110 mm, total length, aggregate in shallow water in Beaver Lake, Alberta. The ratio of number of shiners to that of perch is about 1.5:1. Perch larger than 110 mm leave the aggregation. Eventually they will prey on it from below. Other predators include northern pike and walleye, which lie below the aggregation, and terns and gulls from above. Shiners in the aggregation are 10 times more likely to be taken by fish predators than are perch.
A New Type of Emergence Trap for Collecting Stream Insects
Authors: Hamilton Andrew L.
Published: April 2011

The stream emergence trap described in this note collects the insects that emerge from an enclosed area of substrate. It will function at depths exceeding 12 cm and is designed so that as insects leave the enclosed substrate to emerge they are carried by the current to the downstream end of the trap where there is a quiet area in which they can emerge. The sampler proved particularly effective for collecting adult mayflies, caddisflies, and midges along with their cast exuviae. Major advantages of this emergence trap are that it can be emptied quickly and that the specimens are well suited to both taxonomic studies and studies of organism–substrate relationships.
World Distribution of Brook Trout, Salvelinus fontinalis
Authors: MacCrimmon Hugh R. , Campbell J. Scott
Published: April 2011

During the past century, the endemic range of the brook trout, Salvelinus fontinalis (Mitchill), has been extended to include western North America and the continents of Europe, Asia, Africa, and South America. Water temperature appears to be the most important single factor limiting the geographic range, but adequate precipitation and suitable spawning areas are necessary also for the establishment of self-sustaining populations. It is improbable that, with the possible exception of Asia, the present range of the brook trout will be greatly extended through further attempts at introduction.
A Synopsis and Key to the Recent Ophiuroidea of Washington State and Southern British Columbia
Authors: Kyte Michael A.
Published: April 2011

Twenty-four species are listed with synonomies according to the classification of Spencer and Wright (Treatise on invertebrate paleontology, p. U78–U107, Vol. 1, 1966). Geographical and bathymetrical distributions are also listed. The feeding habits and substrate preferences are listed wherever possible and are correlated with the distributions. A key to the 24 species is presented.
Digestive Response of Rainbow Trout, Salmo gairdneri, to Pellet Diets
Authors: Windell John T. , Norris David O. , Kitchell James F. , Norris James S.
Published: April 2011

Quantitative data are presented for three laboratory experiments concerning rate of gastric evacuation of pellets (fed in gelatin capsules) and pellet components. Rainbow trout, Salmo gairdneri, acclimated to a constant water temperature of 15 C were killed 12 hr after consuming an experimental meal. Subtraction of amount of dry matter remaining at autopsy from dry matter consumed yielded amount of food digested or evacuated or both, from the stomach per unit time.Meals of encapsulated pellet were evacuated from the stomach more rapidly (65.8% decrease in 12 hr) than encapsulated corn oil (42.6%), gelatin (50.8%), a combination of corn oil and gelatin (47.3%), saturated fat (28.8%), or methyl cellulose (50.3%).Groups of fish consuming five capsules equal to approximately 0.65 % of their body weight evacuated 35.9, 45.1, 64.2, 95.5, and 100% at intervals after killing from 6 to 36 hr, respectively. Similar groups consuming seven capsules equal to approximately 1.0% of their body weight evacuated 23.7, 57.9, 70.5, and 86.6% at intervals after killing from 4 to 20 hr, respectively.Ten groups of trout consuming amounts of dry matter equal to 0.24, 0.40, 0.74, 1.11, 1.31, 1.19, 1.59, 1.56, 1.91, and 2.26% of their body weight evacuated 90.7, 81.3, 64.2, 57.9, 56.6, 52.5, 53.4, 51.3, 58.7, and 50.0% in 12 hr, respectively. Gastric motility remains relatively constant once food has entered the stomach. However, when larger meals are fed a greater quantity is evacuated per unit time. This could only be accomplished by changes in volume of gastric contents pumped per peristaltic stroke or number of strokes per unit time.
Stimulation of Sodium Transport Across the Isolated Toad Bladder by 1α-Hydroxycorticosterone from an Elasmobranch
Authors: Grimm A. S. , O'Halloran M. J. , Idler D. R.
Published: April 2011

The mineralocorticoid activity of 1α-hydroxycorticosterone, an interrenal steroid in elasmobranch fish, was determined by the in vitro toad bladder bioassay. It stimulated the transport of sodium across the toad bladder at concentrations of 10−6, 10−7, and 10−8 M. The elasmobranch steroid had approximately 80% of the activity of d-aldosterone; it was slightly less active than aldosterone and corticosterone at the lower concentrations. Protein binding alone does not seem to explain the relative potencies of the two steroids. The concentrations of 1α-hydroxycorticosterone required to stimulate sodium transport across the toad bladder are comparable with those reported in the peripheral blood plasma of Raja radiata and R. ocellata. A seasonal variation in the number of positive responses was observed.
Lipolytic Activity Toward Long-Chain Triglycerides in Lateral Line Muscle of Rainbow Trout (Salmo gairdneri)
Authors: Bilinski E. , Lau Y. C.
Published: April 2011

Lipolytic activity toward long-chain triglycerides was studied in the lateral line muscle of rainbow trout (Salmo gairdneri) by use of tissue slices. Emulsification of substrates with phospholipids was found to be necessary to demonstrate lipolysis, which occurred in decreasing intensity with tripalmitin, triolein, and tristearin. The lipolytic activity showed optimum activity at pH 7.3 and it was inhibited by NaF, protamine, and p-chloromercuriphenyl sulfonate. Albumin had little effect on the activity. Epinephrine did not stimulate lipolysis, but it reduced loss of activity during preincubation.
Greater Dispersal of Wild Compared with Hatchery-Reared Juvenile Atlantic Salmon Released in Streams
Authors: Symons Philip E. K.
Published: April 2011

When wild juvenile (parr) Atlantic salmon (Salmo salar L.) caught by electrofishing, and an equal number of hatchery-reared parr, matched for size with the wild ones, were released at three sites in unfamiliar streams containing resident parr, more hatchery-reared than wild parr could be observed by skin-diving in the areas 1 and 2 weeks later.Observed mortalities of wild parr were not sufficiently higher than those of hatchery parr to explain this result. Nor could a higher proportion of wild parr be found hiding compared with hatchery parr when one release site was electrofished a week after the release. Wild parr were found in greater numbers at points farther from one of the release sites than were hatchery-reared parr, and also more wild fish passed through a salmon counting fence approximately 100 m from a fourth release site than did hatchery-reared parr.This greater dispersal of wild parr from the release site compared with hatchery parr has important consequences to estimates of comparative survival between the two stocks.
Similarity of Otolith Nuclei in Spring- and Autumn-Spawning Atlantic Herring in the Southern Gulf of St. Lawrence
Authors: Messieh Shoukry N.
Published: April 2011

The optical appearance of otolith nuclei was found inadequate for separating spring and autumn spawning herring in the southern Gulf of St. Lawrence. The nuclei of both groups of spawners in 1966 ranged from distinctly hyaline to completely opaque, and the right and left nuclei differed in some fish. Frequency distributions of hyaline and opaque nuclei and of combinations of these types were similar for the two groups of spawners. Frequency distributions of fish length at time of formation of the first annulus did not differ in relation to type of otolith nucleus though they did differ in relation to the widths of the central areas of the scales. The similar frequencies of the various types of nuclei in the two spawning groups may result from the variable hydrographic conditions in the area.
A Comparative Study of Purines Responsible for Silvering in Several Freshwater Fishes
Authors: Eales J. G.
Published: April 2011

The major purines occurring in silvery depositions were analysed for several taxonomically diverse species of freshwater fishes by paper chromatography and ultraviolet-spectrophotometry.Guanine and lesser quantities of hypoxanthine were the only purines found in the skin silvery layers of the channel catfish (Ictalurus punclatus), burbot (Lota lota), brook stickleback (Culaea inconstans), pike (Esox lucius), walleye (Stizostedion vitreum), sauger (S. canadense), goldfish (Carassius auratus), brook trout (Salvelinus fontinalis), and trout perch (Percopsis omiscomaycus). Possibly both guanine and hypoxanthine generally occur in fish skin silvery layers.In the pike and walleye the purines in the homogenized eye were examined and guanine and hypoxanthine recovered. However, for the swimbladder of pike, walleye, and channel catfish guanine alone was found.
Lobster Larvae off Pictou, Nova Scotia, Not Affected by Bleached Kraft Mill Effluent
Authors: Scarratt D. J.
Published: April 2011

A survey made about 1 year after the opening of a bleached kraft mill near Pictou, Nova Scotia, indicates that the mill effluent is not having any immediate or direct effect on the distribution or abundance of lobster larvae.
Occurrence of Coregonus artedii and C. zenithicus in Barrow Lake, Alberta
Authors: Paterson Colin G.
Published: April 2011

The variation in size at maturity and meristic characters of ciscoes inhabiting lakes in northern Alberta has made the assignment of specific names tenuous. Study of populations of Coregonus artedii and C. zenithicus in a small lake revealed that these two species can be effectively separated by gill-raker counts. A comparison with three other populations of C. artedii suggests that gill-raker counts will effectively distinguish these species in other northern Alberta lakes.
Uptake of Dieldrin by Isolated Perfused Gills of Rainbow Trout
Authors: Fromm Paul O. , Hunter Robert C.
Published: April 2011

Transfer of dieldrin from environmental water into the vascular system of isolated perfused gills of rainbow trout was demonstrated. Transfer occurred only when plasma protein, or more probably plasma lipoprotein, was present in the perfusion fluid. Over the range of concentrations tested transfer was always down a concentration gradient. Larger quantities of dieldrin were absorbed on or bound in gills perfused with plasma than in those perfused with Ringer solution or a protein-free synthetic tissue culture medium (TC-199).
Breeding and Fecundity of the Glass Shrimp, (Pasiphaea multidentata (Decapoda, Caridea), in the Gulf of Maine
Authors: Apollonio S.
Published: April 2011

About 1450 specimens of the decapod crustacean Pasiphaea multidentata were collected in deep waters of the Gulf of Maine in 1966–69, and were examined for size, sex, weight, breeding, fecundity, and feeding. The sizes and sex ratios of the catches vary with the egg-bearing seasons, suggesting that ovigerous females are susceptible to greater predation. The data do not permit estimates of growth rates or age of maturity. The ratios of carapace length to total length differ in males and females. Two egg clutches per female per year were produced, the second clutch being smaller in numbers, probably because of "reproductive fatigue" in the female. In each clutch the number of eggs produced is a linear function of carapace length. About 50% of the stomachs were empty. Eighteen per cent contained crustacean remains of which about half could be identified as remains of the copepods Metridia longa, M. lucens, and Euchaeta norvegica. Epizoic suctorians were found on a few shrimps.
Epibenthic Algal Production and Community Respiration in the Sediments of Marion Lake
Authors: Hargrave Barry T.
Published: April 2011

Gross epibenthic algal production and benthic community respiration in Marion Lake, British Columbia, were measured during 1968 by following changes in dissolved oxygen over undisturbed sediment cores. No measurable chemical uptake of oxygen occurred during short-term experiments. Multiple regression analyses showed that in situ oxygen production by epibenthic algae was directly related to temperature, light, and community respiration and inversely related to day length. Mean weekly values of these variables were substituted into the regression to estimate annual gross algal production on sediment at various depths in Marion Lake. Photosynthetic efficiency ranged from 0.4 to 3.1% and increased with depth of water over the sediment. Sedimentary chlorophyll was stratified with highest concentrations in the upper few centimeters of sediment which corresponded to the depth of oxygen penetration.Measurements of in situ oxygen consumption showed that community respiration was related to temperature, oxygen concentration, and day length in a curvilinear manner. Oxygen uptake was minimal at midday and increased during the night. A multiple linear regression was derived, after suitable transformations, and mean weekly values of variables substituted to estimate annual community respiration.Bacterial respiration was measured as the difference in total community respiration when antibiotics were added to water over undisturbed sediment cores. Less than 30% of community oxygen consumption was inhibited by antibiotic treatment during the summer, whereas over 45% reduction occurred during the winter. Bacterial respiration was directly related to temperature and showed no significant correlation with oxygen concentration or other variables shown to affect community respiration. Macrofauna respired 33% of the total oxygen consumed by sediment cores during June, and epibenthic algae were estimated to account for 23% of community respiration. Net epibenthic algal production, calculated by correcting gross oxygen production for estimated algal respiration, was 85% of gross production during the summer.Annual carbon flux across the sediment in Marion Lake was estimated by comparing processes of carbon addition and removal. From previous studies, phytoplankton and macrophytes added 0.8 and 18 g C m−2 year−1. Organic particulate matter from the inlet stream, other than macroscopic debris, contributed 143 g C m−2 year−1 and average gross epibenthic algal production was 40 g C m−2 year−1. Community respiration consumed 57 g C m−2 year−1. An additional 143 g C m−2 year−1 was lost as particulate matter in the outlet stream and emerging insects could remove 1.3 g C m−2 year−1. Only 8 g C m−2 was estimated to accumulate below the aerobic surface–sediment layer annually.
Seasonal Activity and Feeding Pattern of Brown Trout (Salmo trutta) in a Dartmoor Stream in Relation to Availability of Food
Authors: Chaston I.
Published: April 2011

In laboratory tests, brown trout were most active between dusk and dawn from spring to autumn, but the percentage of the total activity that occurred during daylight was higher in the summer than in the other two seasons. Analysis of the variation in the weight of stomach contents during 24 hr in the three seasons showed a higher peak in weight at noon in summer than in the other seasons. The difference was related to an increased consumption of material of terrestrial origin, which other work showed to be most available to the fish between 09.00 and 12.00 hr. No relationship was found between the times of maximum occurrence of benthic and emergent items in the stream and of their consumption by trout. The increase in daytime activity during the summer was also evidently related to increased consumption of terrestrial material.
Open-Water Orientation of White Bass, Roccus chrysops, as Determined by Ultrasonic Tracking Methods
Authors: Hasler Arthur D. , Gardella Edward S. , Horrall Ross M. , Henderson H. Francis
Published: April 2011

In the spring and summer of 1965, 26 white bass, Roccus chrysops (Rafinesque), were displaced to open water on Lake Mendota, Wisconsin, and their paths traced by means of ultrasonic transmitters carried in the stomachs of the fish and receiving gear located on boats. Seventeen fish captured by fyke nets on their spawning ground were displaced 1.6 km west-southwest to a mid lake release point. Two months after the spawning season nine fish, captured by hook-and-line, were displaced 3.1 km east-northeast from their capture area to the same release point. The mean tracking time for all 26 fish was 7.31 hr.Both the spawning and nonspawning fish maintained steady courses over long distances, and both groups showed a distinct directional preference for the eastern half of the lake where the spawning grounds are located. This open-water orientation helps explain the rapid homing performance, observed in previous experiments, of displaced spawning white bass, and also demonstrates that white bass possess mechanisms for orienting to directional cues present in their natural environment.Water currents, wind-generated surface waves, and the sun were examined as possible directional cues used by the fish. Although there was some evidence supporting the use of each of these cues, the problem of orientation mechanisms remains obscure. It was determined, however, that the observed movements of the fish cannot be explained as simply passive drift by the water currents.
Sebastodes flavidus, a Shelf Rockfish Feeding on Mesopelagic Fauna, with Consideration of the Ecological Implications
Authors: Pereyra Walter T. , Carvey Jr. Forrest E. , Pearcy William G.
Published: April 2011

Yellowtail rockfish (Sebastodes flavidus) aggregated along the southern edge of the Astoria Canyon, probably in response to the increased availability of mesopelagic food. The myctophid Stenobrachius leucopsarus was the dominant food organism.
Effect of the Rate of Storm Growth on Subsequent Surge Elevations
Authors: Holland Geoffrey L.
Published: April 2011

The surge elevation due to an instantaneously applied generating force over one-half of an infinite rotating sea was given by Crease (Proc. Roy. Soc. London, Ser. A: 233, 1955). This note describes the effect of modifying the applied force to allow it to reach its maximum value over a finite period of time.
Simple Stream Tank Simulating a Rapids Environment
Authors: Gee J. H. , Bartnik V. G.
Published: April 2011

The construction of an inexpensive stream tank providing a rapids environment of 0.6 m2 with a maximum velocity of 0.5 m/sec is described. Compressed air and a large aquarium are required to create an adequate volume of flow.
Effect of Magnesium Sulphate and Cryoprotective Agents on Free Fatty Acid Formation in Cold-Stored Fish Muscle
Authors: Jonas R. E. E.
Published: April 2011

Rainbow trout (Salmo gairdneri) muscle was stored in 5% MgSO4 in Ringer's solution, 15% dimethyl sulphoxide in Ringer's solution, and 6% dextran in 0.9% NaCl, at −10 C for periods of 2, 4, 8, and 12 weeks. The regular increase in free fatty acid (FFA) content was used as an index of muscle degradation. For the 12-week storage period at −10 C, the FFA content varied from 17.9 μmoles in fresh muscle to a maximum of 222 μmoles/100 g muscle for nonimmersed muscle. Samples immersed in MgSO4 solution alone showed a consistent statistically significant inhibition in FFA formation when compared with immersed and nonimmersed muscle controls. Immersion in DMSO produced the least visual deterioration in appearance, colour, and firmess of texture.
Preliminary Report on the Fecundity of Mytilicola orientalis
Authors: Johnson Eugene A. , Chew Kenneth K.
Published: April 2011

Egg cases of the endoparasitic copepod Mytilicola orientalis Mori were examined from samples dissected from Pacific oysters (Crassostrea gigas) and bay mussels (Mytilus edulis) from Humboldt Bay, California, Yaquina Bay, Oregon, and Willapa Bay and Hood Canal, Washington. There was little variation between the number of eggs in both egg cases from an individual female. On the bases of two egg sacs per female approximately 252–368 eggs are produced.
Morphological Characteristics of Infectious Pancreatic Necrosis Yirus in Trout Pancreatic Tissue
Authors: Lightner Donald , Post George
Published: April 2011

Electron microscopical observations were made of infectious pancreatic necrosis (IPN) virus in thin sections of pancreatic acinar cells of rainbow trout (Salmo gairdneri). The virus and trout used in this study were obtained from a naturally occurring IPN epizootic in Colorado trout hatcheries and rearing units in 1968. IPN virus particles were found in large numbers in pancreatic acinar cells. Virus particles were associated most often with inclusion bodies composed of masses of virus particles and cell debris or large crystalline aggregations that were encircled by a single-layered membrane. Mature virus particles were found to average 57 nm in diameter and were hexagonal in profile.
Heading and Gutting of Capelin With Special Hand Shears
Authors: Sepic K. , MacCallum W. A.
Published: April 2011

The hand shears traditionally used for heading and gutting sardines in Mediterranean canneries were shown to increase the heading rate for capelin to about four times that prevailing in Newfoundland plants, where simple knives are used. The shears could greatly increase production efficiency in canning capelin, small herring, smelt, and other inland species at small Canadian plants and could be useful in experimental laboratories and households, especially those of sports fishermen and fish food enthusiasts.