bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationships of Female Age and Size to Embryo Number and Size in the Shiner Perch, Cymatogaster aggregata
Authors: Wilson Dennis C. , Millemann Raymond E.
Published: April 2011

Ages, lengths, and weights were determined for 124 female shiner perch, Cymatogaster aggregata Gibbons, collected in Yaquina Bay, Oregon, from May 17 through June 29, 1968. Embryos (1005) were obtained from 111 gravid females either by dissection (737) or at parturition in the laboratory (268). Embryo lengths, weights, and numbers per female parent were determined.As females increased in age from 1 to 6 years, their mean fork length increased from 9.32 to 13.65 cm, their weight from 13.65 to 47.78 g, and the mean number of embryos per parent female increased from 5.83 to 20.00. The equations and their correlation coefficients (R) computed for the relationships of embryo number (Y) to parent female fork length, weight, and age are, respectively: log Y = −1.892 + 2.735 log X (R = 0.89); Y = 1.131 + 0.313 X (R = 0.70); and Y = 4.23 + 1.73 X (R = 0.51). Embryo size at birth was also directly related to female parent size. The equations computed for the relationships of total length of embryo at birth (Y) to parent female fork length and parent female weight are, respectively: Y = 24.211 + 1.620 X (R = 0.79); and Y = 0.384 + 0.015 X (R = 0.72). The equation computed for the relationship of embryo weight (Y) to embryo length at birth is Y = −2.266 + 0.712 X (R = 0.95).
Life Cycles of Limnocalanus macrurus and Senecella calanoides, and Seasonal Abundance and Vertical Distributions of Various Planktonic Copepods, in Parry Sound, Georgian Bay
Authors: Carter John C. H.
Published: April 2011

The life cycles and vertical distributions of Limnocalanus macrurus and Senecella calanoides and the seasonal abundance and vertical distributions of adults of other planktonic copepods in Parry Sound, Georgian Bay, were determined from diurnal vertical plankton hauls taken on 14 occasions from June 19, 1967, through November 11, 1968. The most abundant cyclopoid copepod on most occasions was Cyclops bicuspidatus thomasi. Tropocyclops prasinus was common, particularly in summer and autumn. Mesocyclops edax and Cyclops vernalis were scarce. Cyclops bicuspidatus thomasi and T. prasinus were usually concentrated in the upper strata, T. prasinus seldom being deeper than 3 m during summer.The most abundant calanoid copepod was Diaptomus ashlandi. Diaptomus minutus and D. oregonensis were also common, but D. sicilis was rare. Diaptomus ashlandi and D. oregonensis occupied much the same depths in the metalimnion during the periods of thermal stratification but were deeper in spring and fall. Diaptomus minutus was concentrated mainly in the epilimnion even when thermal stratification was slight. Epischura lacustris and Eurytemora affinis were scarce. Limnocalanus macrurus was abundant and monocyclic, becoming adult in late spring but not spawning until autumn; older copepodites inhabited somewhat deeper strata than younger stages. Senecella calanoides was less abundant than L. macrurus but was also monocyclic, becoming adult in autumn and spawning almost immediately; all instars were usually found in deeper water than L. macrurus. The possibility that S. calanoides, because of its longer period of development, is better adapted to life in Parry Sound than L. macrurus is discussed.
Body Size in White Whales, Delphinapterus leucas
Authors: Sergeant D. E. , Brodie P. F.
Published: April 2011

Measurements of length, girth, and weight show that male white whales grow larger than females. The smallest white whales come from western Hudson Bay, the White Sea, and Bristol Bay, Alaska. Animals of intermediate size inhabit all other arctic Canadian localities sampled and also the St. Lawrence River and the Kara and Barents seas. The largest white whales inhabit West Greenland waters, the Okhotsk Sea, and the coast of Sakhalin. Extreme differences in body weight of adult males are about threefold. Nonoverlapping differences in size indicate isolation of some adjacent populations of white whales; equal or overlapping sizes suggest, but cannot prove, mixing of other populations. Size can be positively correlated with marine productivity, being lowest in the arctic and in estuaries and highest in subarctic seas. Since white whales most often grow largest at the southern ends of their range, their restriction to the arctic is attributed either to competition with certain of the Delphinidae or to predation from killer whales, Orcinus orca L., or to both. Both putative competitors and predator lack adaptations for arctic life.
Allocation of Weight and Length Measurements for Estimation of the Average Weight of Juvenile Sockeye Salmon
Authors: Mathisen Ole A.
Published: April 2011

The regression of weight on length of juvenile sockeye salmon was utilized to determine the optimal division of weight and length measurements in order to obtain minimum variance of the average weight estimate with a fixed expenditure of time to observations.
Bacterial Flora of Some Algal Foods Used for Rearing Bivalve Larvae
Authors: Murchelano Robert A. , Brown Carolyn
Published: April 2011

The heterotrophic bacteria present in 15 mass cultures of six different genera of algae used for feeding larvae of the Atlantic oyster, Crassostrea virginica, and the hard clam, Mercenaria mercenaria, were isolated, identified, and their physiology studied. Of the 120 isolates obtained, 118 (98.3%) were asporogenous, gram-negative rods — types commonly found in marine waters. The majority of the isolates, 98 (81.6%), belonged to the genus Pseudomonas.
Tetrachloro-o-benzoquinone as a Component in Bleached Kraft Chlorination Effluent Toxic to Young Salmon
Authors: Das B. S. , Reid S. G. , Betts J. L. , Patrick K.
Published: April 2011

Evidence is given that tetrachloro-o-benzoquinone is involved in the toxicity of bleached kraft chlorination effluent (BKCE) to young Atlantic salmon, Salmo salar. The main experimental support was isolation of tetrachlorocatechol from whole BKCE and from a BKCE fraction toxic to salmon, after reduction of both with sodium borohydride. Tetrachloro-o-benzoquinone was shown to be toxic to salmon at low concentrations. Instability of the toxic component in BKCE and substantial loss of toxicity upon treatment of BKCE with sulfur dioxide agreed with the properties of tetrachloro-o-benzoquinone in water solution.
Larval Swordfish (Xiphias gladius) from Three Localities in the Western Atlantic
Authors: Tibbo S. N. , Lauzier L. M.
Published: April 2011

In February 1965, 47 larval swordfish were caught in three regions of the western North Atlantic: near Cape Hatteras, N.C.; off the east coast of Florida; and near the Virgin Islands. The captures were made in waters where the ranges of both temperature (23.4–25.6 C) and salinity (35.81–36.36‰) were small. The data support the conclusions of other workers that swordfish spawn in an area west of the Straits of Florida and in the most southern part of the Sargasso Sea.
Distribution of Anotopterus pharao in the North Atlantic and Comparison of Specimens of A. pharao from the Western North Atlantic with Those from Other Areas
Authors: Templeman Wilfred
Published: April 2011

Two records of Anotopterus pharao Zugmayer from the Labrador Shelf, and three from the Grand Bank and vicinity, are the only records of captures from these areas and the only ones from the Newfoundland area apart from four Soviet records from Flemish Cap. One of the Grand Bank captures, October 1952, and a Labrador capture, September 1954, are the earliest records from the Newfoundland area.Meristic and morphometric data indicate that these Newfoundland area specimens and two other west Greenland and one southeast Greenland specimens of Anotopterus examined by me are referable to Anotopterus pharao Zugmayer, as are all known specimens from the eastern Atlantic, and are similarly specifically related to Pacific and antarctic specimens. However, a few differences will need to be resolved by studying a larger number and size range of specimens from all areas of distribution.
Occurrence of Trigonelline (N-Methyl Nicotinic Acid) in the Adductor Muscle of a Lamellibranch, the Sea Scallop (Placopecten magellanicus)
Authors: Hiltz Doris Fraser
Published: April 2011

Trigonelline, associated with its isomer homarine, has been found in amounts ranging from 0.7 to 1.3 μmoles/g in scallop adductor muscle. Separation of the two betaines was achieved by column chromatography on a cation-exchange resin, using a linear gradient of 2 N HCl into H2O. Identification of trigonelline was based on spectral properties and on behavior in thin-layer, paper, and column chromatography.
The Meromixis of Sunfish Lake, Southern Ontario
Authors: Duthie Hamish C. , Carter John C. H.
Published: April 2011

In the meromictic Sunfish Lake the large populations of phytoplankton that are observed periodically were associated with circulation of the mixolimnion. Perhaps some organic dissimilation took place in the lower mixolimnion, recycling nutrients during spring and fall circulation. Phytoplankton was practically absent from the epilimnion during the summer but a population of Oscillatoria agardhii remained in the metalimnion, where it was responsible for a pronounced and persistent metalimnetic oxygen maximum. The monimolimnion contained about 5100 mg/liter of dissolved solids and the upper mixolimnion about 2200 mg/liter. Ventilation of the monimolimnion did not always coincide with circulation and subsurface springs may have been responsible. Circulation to the lake bottom was observed only once in 18 months.
Further Evidence for a Three-Year Oocyte Maturation Time in the Winter Flounder (Pseudopleuronectes americanus)
Authors: Dunn R. S.
Published: April 2011

Evidence is presented for autumn growth of yolkless oocytes, which would tend to split the oocytes into two size groups.
Distribution of Ingested Zinc-65 in the Tissues of Some Marine Crustaceans
Authors: Fowler Scott W. , Small Lawrence F. , Dean John M.
Published: April 2011

Autoradiographs of tissues of euphausiids and shrimps fed 65Zn through a food chain showed the isotope located primarily in the interstitial spaces between muscle fibers, in the eye mainly between the rhabdoms and crystalline cones of adjacent ommatidia, within the exoskeleton, and on the interior surface of the exoskeleton. Comparisons of the autoradiographic evidence with concentrations of radiozinc and stable zinc in the various dissected tissues were in good agreement. The specific areas of 65Zn localization were much the same as those seen in an earlier study of similar organisms that accumulated 65Zn directly from sea water; thus, it appears that 65Zn, and therefore zinc, is highly labile in marine crustaceans and will accumulate in certain specific locations regardless of the mode of uptake. The rates at which various tissues became saturated with 65Zn were dependent upon mode of uptake, however. Because most of the 65Zn was located intercellularly, and not intracellularly, most ingested zinc apparently accumulates in excess of the animals' needs and is not used metabolically.
Seasonal Depth Distributions of Landlocked Atlantic Salmon, Brook Trout, Landlocked Alewives, and American Smelt in a Small Lake
Authors: Lackey Robert T.
Published: April 2011

Seasonal depth distributions of landlocked Atlantic salmon (Salmo salar), brook trout (Salvelinus fontinalis), landlocked alewives (Alosa pseudoharengus), and American smelt (Osmerus mordax) were determined monthly in Echo Lake, Maine, using vertical and horizontal gillnets.Salmon were wide-ranging fish, but generally not captured in very shallow or very deep water. Brook trout were primarily an inshore species, not often captured in water deeper than 25 ft, and nearly always found close to the lake bottom. The majority of captured alewives were taken from shallow to middepths (0–30 ft) in summer and fall and in deep water during winter and spring. Smelts were widely distributed, but the majority were captured in water deeper than 30 ft every month.No clear temperature or dissolved oxygen preference could be shown for any of the four species.
Biochemical Implications of Seasonal Trends in the Iodine Values and Free Fatty Acid Levels of Commercially Produced Atlantic Coast Herring Oils
Authors: Ackman R. G. , Eaton C. A.
Published: April 2011

Annual surveys of commercial herring oils produced in summer and fall off southwestern Nova Scotia and in winter and spring off southwestern Newfoundland showed iodine values (IV) mostly within the range 135 to 105 in both locations for the years 1965–70. Two systematic trends in IV with season were detected. The first extended uniformly over the whole of each fishery season and was limited to no more than ± 5 IV units. It is believed to represent the influence of long-term average environmental conditions that may vary from year to year and that establish the basic fatty acid compositions of the fish entering the fishery. The second was observed as a seasonal decline, over 2–3 months, of 20 IV units in the Nova Scotia fishery, and of 10 IV units in the Newfoundland fishery. It is proposed that this short-term effect follows from an increase in the relative proportion of the low-density, long-chain, monoethylenic fatty acids characteristic of clupeid oils that could decrease residual fat density at a time of general fat depletion and corresponding density increase for the fish as a whole.Free fatty acids (FFA) in freshly produced oils were also examined. In both fisheries % FFA seldom exceeded 1 and under optimum conditions the % FFA were consistently about 0.2–0.3. Annual seasonal % FFA effects were apparently restricted to an increase in April in the Newfoundland fishery associated with high IV oils of a pink colour denoting heavy spring feeding.
β-Glucuronidase and Arylsulphatase in some Marine Invertebrates of the Canadian Atlantic Coast
Authors: Hiltz Doris Fraser , Lightle Thérèse E.
Published: April 2011

β-Glucuronidase and arylsulphatase activity in the digestive gland tissue varied widely among 15 invertebrate species examined. β-Glucuronidase activity was highest in three algae-feeding species of Gastropoda, Littorina littorea, L. obtusata, and Acmaea testudinalis, with successively lower levels in lamellibranchs, carnivorous gastropods, crustaceans, and echinoderms. The sea scallop Placopecten magellanicus, the clam Mya arenaria, and a freshwater mussel Elliptio complanatus were particularly rich in arylsulphatase. No apparent correlation existed between β-glucuronidase and arylsulphatase activity among the species studied.
Parasitic Copepods of Sebastodes alutus Including Chondracanthus triventricosus sp.nov. and Colobomatus kyphosus sp.nov.
Authors: Sekerak A. D.
Published: April 2011

Sixty-six specimens of Sebastodes alutus, the Pacific ocean perch, collected from the coast of Oregon and British Columbia were examined for parasitic copepods. The six species identified are Chondracanthus pinguis Wilson, 1912, Chondracanthus triventricosus sp.nov., Clavella parva Wilson, 1912, Brachiella robusta (Wilson 1912) Kabata, 1970, Colobomatus kyphosus sp.nov., and Sarcotaces arcticus Collett 1874. Colobomatus kyphosus is the second species of the genus to be described from the eastern Pacific and Ch. triventricosus is the second chondracanthid to be found in nasal cavities. Sarcotaces arcticus is reported as a parasite of S. alutus for the first time. Details of the appendages of each new species are described and illustrated.
Reproductive Cycle, Size at Maturity, and Sexual Composition of Commercially Harvested Weathervane Scallops (Patinopecten caurinus) in Alaska
Authors: Hennick Daniel P.
Published: April 2011

Findings of this study indicated that scallops spawn in the summer, primarily during early June, and also through mid-July. Spawning is complete, and only one annual spawning occurs. Sexual composition of mature scallops appeared as a 50:50 ratio. Most scallops were mature when three or more concentric rings (annual rings) were present on the upper valve and all after four or more were present. Scallops off Yakutat grow slower and are smaller at maturity than scallops off Kodiak Island. Growth and size differences did not seem directly related to time of maturity.
Discovery of Brachiella lageniformis (Copepoda: Lernaeopodidae) in the Canadian Pacific and its Significance to Zoogeography of the Genus Merluccius (Pisces: Teleostei)
Authors: Kabata Z.
Published: April 2011

Brachiella lageniformis, hitherto known only from the Atlantic coast of Argentina, was found off the east coast of Vancouver Island, on the gills of Merluccius productus. Both male and female are described and illustrated in detail. The significance of this find for Szidat's views on the origin of the genus Merluccius is discussed. A proposal is made to suppress the genus Parabrachiella and to place all its five species (P. rostrata, P. insidiosa, P. australis, P. spinicephala, and P. incurva) in the genus Brachiella.
Pigmentation of Brook Trout (Salvelinus fontinalis) by Feeding Dried Crustacean Waste
Authors: Saito Akira , Regier L. W.
Published: April 2011

Shrimp and crab wastes were fed to yearling brook trout for 12 weeks. Diets containing 20 and 30% shrimp waste, 20% crab waste, and 0.004% canthaxanthin were compared with a commercial trout diet. The carotenoid contents of the flesh and skin were highest with the canthaxanthin-fed fish, but the 20% shrimp-waste-fed fish had the most desirable color visually within the feeding period used.
Effects of Jaw Tagging on Growth and Scale Characteristics of Landlocked Atlantic Salmon, Salmo salar
Authors: Warner Kendall
Published: April 2011

Recapture of 165 annual and biennial spawners of landlocked Atlantic salmon (Salmo salar) from 1239 fish tagged on the spawning grounds from 1953 to 1955 at the Fish River Lakes, Maine, showed that jaw-tagged females grew significantly slower than untagged female of identical ages and cycles. For most maturing male salmon, growth increments were not significantly reduced by jaw tagging. A tendency for decreased growth increments with increase in age was apparent for both tagged and untagged fish.Recognizable annuli were formed on the scales of 77–100% of 97 male salmon and of 74–97% of 187 female salmon between tagging and recapture. A significantly smaller percentage of females (74%) than males (100%) at large 1 year and recaptured on the spawning grounds had formed a recognizable annulus, but there was no significant difference between females (86%) and males (91%) recaptured by anglers. The significantly lower annulus recognition for annual female spawners was attributed to their demonstrated slower growth rate and possibly resorption of minimal marginal scale growth.Spawning checks were recognizable on the scales of 69–100% of 97 males and 49–78% of 187 females recaptured. Male salmon recaptured on the spawning grounds formed a significantly higher percentage of recognizable spawning checks than females (both annual and biennial spawners), but there were no significant differences between sexes for angler-recaptured fish. Lower reliability in spawning check recognition for females was attributed to less severe marginal resorption resulting in no spawning check being formed or obliteration of previous spawning checks by resorption of the small amount of marginal scale increment made by some annually spawning females, or both.
Giant American Brook Lampreys, Lampetra lamottei, in the Upper Great Lakes
Authors: Manion Patrick J. , Purvis Harold A.
Published: April 2011

Five female American brook lampreys, Lampetra lamottei, collected in lakes Michigan and Huron averaged nearly twice as long and about six times as heavy as American brook lampreys of normal size. Three factors suggested that the giant lampreys may have fed parasitically after metamorphosis: morphological adaptations of the species for parasitic life, their large size, and absence of extremely large ammocetes among a million sampled.
Some Physiological Effects of Handling and Tricaine Methane-sulphonate Anesthetization upon the Brook Trout, Salvelinus fontinalis
Authors: Houston Arthur H. , Madden Jane A. , Woods R. John , Miles Harry M.
Published: April 2011

The effects of handling and anesthetization with tricaine methanesulphonate (Ayerst "Finquel") upon brook trout (Salvelinus fontinalis) have been investigated with reference to selected hematological and cardioventilatory parameters, and several aspects of body fluid chemistry. Alterations in hemoglobin, hematocrit, and total dissolved solids suggest that exposure to the anesthetic prompts a rapid hemoconcentration. Water content increases, and the plasma, tissue, and estimated cellular levels of several of the major electrolytes (sodium, potassium, calcium, and magnesium) are altered. Observations upon cardiac activity, dorsal aortic pressure, and ventilatory rate and amplitude support the hypothesis that Finquel exerts a depressive influence upon central autonomic functions. Handling alone leads to significant changes in plasma glucose and lactate levels, and in the concentrations and distributions of a number of the electrolytes investigated.
Degradation of Inosine 5′-Monophosphate in the Skeletal Muscle of Several North Atlantic Fishes
Authors: Dingle J. R. , Hines J. A.
Published: April 2011

The rates of breakdown of inosine 5′-monophosphate (IMP) and of its product, inosine (Ino), varied considerably in the muscles of Atlantic cod, haddock, pollock, Atlantic halibut, American plaice, and winter flounder when stored in ice. Haddock and Atlantic halibut were noteworthy in having a very slow rate of breakdown of IMP in relation to the other species. Variations of the rate of dephosphorylation of IMP among individual winter flounder appear to be due to differences in muscle pH. In homogenates of the muscles investigated, the maximum rates of breakdown of IMP occurred in the pH range 8.6–9.4, and were much greater than in the pH range of muscle. The effect of pH on the breakdown of Ino was less pronounced. In haddock and Atlantic halibut there was little or no loss of endogenous IMP when the muscle was cooked at 260 or 100 C; IMP added to Atlantic cod before cooking was also stable.
A Simple Field Technique for Obtaining Small Samples of Muscle from Living Fish
Authors: Uthe J. F.
Published: April 2011

A method for obtaining small samples of muscle from living fish is described. The procedure employs a modified Silverman biopsy needle and samples of approximately 40 mg are obtained. Survival rate in a group of fish held in aquaria and periodically biopsied is excellent. Quantitative mercury analyses were carried out on multiple biopsy samples from a group of fish and the precision of the results is as good as that obtained when analyses were carried out on excised portions of muscle.
Changes in Blood Lactic Acid Concentrations in Alewives (Alosa pseudoharengus) During Passage Through a Pool and Weir Fishway
Authors: Dominy C. L.
Published: April 2011

Blood lactic acid concentration of anadromous alewives (Alosa pseudoharengus) sampled during their upstream migration through a pool and weir fishway was not extremely high (46.7 mg/100 ml) and the degree of exercise exhibited during ascent was judged to be moderate. For fish that were subjected experimentally to severe exercise, the concentration (108.7 mg/100 ml) was more than five times that for rested fish (18.9 mg/100 ml). Of the three groups of fish sampled directly from the fishway pools, only one had an average concentration that differed significantly from that for the rested state.
Investigations Into the Relation Between Integrated Echo Voltage and Fish Density
Authors: Thorne Richard E.
Published: April 2011

An echo integrator, working in combination with an echo sounder, measures the total voltage of the fish echoes received from a given depth interval and sums these voltages over time. Investigations were made on the relation between integrated echo voltage and fish density for juvenile sockeye salmon (Oncorhynchus nerka) in Lake Washington and Pacific hake (Merluccius productus) and Pacific herring (Clupea harengus pallasi) in Puget Sound. When fish were distributed at densities at which they could be acoustically resolved as individual targets, the relation between net catch and integrated voltage was linear. At higher densities when the fish echoes were multiple targets, the net catch was related to the square of the integrated voltage.
Perception of Polarized Light by Yearling Sockeye Salmon (Oncorhynchus nerka)
Authors: Dill P. A.
Published: April 2011

Food-conditioning experiments conducted in the laboratory demonstrated that groups of yearling sockeye salmon (Oncorhynchus nerka) can discriminate between vertical and horizontal planes of linearly polarized light. Removal of the adipose eyelid, a possible analyser of polarized light, did not abolish the response. The findings support the hypothesis that these fish can use polarization patterns for orientation during their seaward migration.
Some Effects of Salinity and Temperautre on Early Development of Pacific Herring (Clupea pallasi)
Authors: Alderdice D. F. , Velsen F. P. J.
Published: April 2011

Pacific herring (Clupea pallasi) eggs were incubated in the laboratory at 13 different salinity–temperature combinations (ranges: 5–45‰ S, 4–14 C). Data were obtained on rate of development, larval length at hatching, percent total hatch, and percent viable hatch. Subsamples of larvae, held in their incubation media, provided data on posthatching survival and larval size at yolk sac absorption. Maximum percent viable hatch, larval size at hatching, and maximum survival to yolk sac absorption occurred in a trial at 16.41‰ S, 6.85 C. Optimum conditions were calculated by response surface analysis — maximum total hatch: 12.01‰ S, 6.46 C; maximum viable hatch: 16.98‰ S, 8.33 C; maximum length of newly hatched larvae: 20.00‰ S, 5.54 C. Maximum percent viable hatch of largest larvae in the shortest incubation period is estimated to occur at or near 16.98‰ S, 8.7 C. Abnormalities of the lower jaw were present in larvae from eggs incubated at temperatures of 4.0 and 4.71 C. Pacific herring eggs are considered euryhaline and stenothermal. A comparison of laboratory and field observations suggests that occurrence and abundance of herring is related to the availability and extent of spawning salinities between 8 and 28‰. Moreover, catch statistics suggest that population abundance in North American waters is associated with spawning temperatures of 5–9 C, abundance is limited by temperatures of 9–10 C, and the maximum temperature for spawning is about 10 C. From the current study, survival of viable larvae to yolk sac absorption would place the lower limit of thermal tolerance of Pacific herring eggs between 4 and 5 C.
Offshore Distribution of Pacific Herring (Clupea pallasi) on Basis of Records from Fur Seal Stomachs
Authors: Taylor F. H. C.
Published: April 2011

An examination of stomachs of fur seal (Callorhinus ursinus) taken off the coast of southern British Columbia and Washington from 1958 to 1969 indicated that Pacific herring (Clupea pallasi) were confined mainly to the continental shelf. Herring were most numerous in fur seal stomachs off Barkley Sound. Few occurred north of Cape Cook or from Cape Flattery south to the Columbia River. None were found from seals taken near the Cobb Sea-mount.
Sterols of a Brachiopod, Terebratalia transversa
Authors: Idler D. R. , Wiseman P.
Published: April 2011

The sterol composition of a brachiopod is remarkably similar to that of a pelecypod. The principal sterols of both are cholesterol, brassicasterol, and 24-methylenecholesterol, and even the relative proportions are nearly identical. These invertebrate groups were classed together before this century, but have since been shown to be structurally unrelated.
Occurrence of Gas-Bubble Disease in Three Species of Bivalve Molluscs
Authors: Malouf Robert , Keck Richard , Maurer Don , Epifanio Charles
Published: April 2011

Gas-bubble disease was observed in adult oysters and hard clams held in heated running sea water during the winter. Heating the cold sea water in closed heat exchangers caused it to become supersaturated with atmospheric gases. Exposure of the animals to this water caused the formation of gas-filled conchiolin blisters on the valves of the oysters. Bubbles of gas were observed in the gill filaments of the oysters and clams and in the mantle tissue of the oysters. Any method, such as the use of baffles or an aerated head tank, that reduces the dissolved gas concentration in the water will help prevent the disease.
The Relation Between Lobster Abundance, Sea Urchins, and Kelp Beds
Authors: Mann K. H. , Breen P. A.
Published: April 2011

When subtidal communities are disturbed and sea urchin populations expand, they frequently overgraze their food supply, eliminating large seaweeds from considerable areas. The hypothesis is advanced that the lobster is a key species, controlling sea urchin populations in eastern Canada, and that reduction of lobster populations below a critical density has led to overgrazing of seaweeds in many places.
Effects of Solar Radiation and Upwelling on Daily Primary Production off Oregon
Authors: Small Lawrence F. , Curl Jr. Herbert , Glooschenko Walter A.
Published: April 2011

Primary production was measured in units of gC m−2 day−1 (=P) and gC (gChla)−1 day−1 on a per meter squared basis (=PChl) for 4 years in Oregon coastal waters and offshore areas. P, and particularly PChl, were functions of daily photosynthetically usable radiation inshore except in summer, and offshore apparently during all seasons. Values of P and PChl for a given daily input of usable radiation were higher inshore than offshore, probably because of more efficient use of penetrating light by the relatively heavy coastal phytoplankton populations in nutrient-rich water. Evidence is presented that inshore phytoplankton populations in winter are acclimated to low light relative to inshore populations in spring.P and PChl are related to the interaction of daily radiation and degree of upwelling in Oregon coastal waters in summer. P is a function of photic depth offshore and inshore, except in summer. Probably the presence of large quantities of non-photosynthesizing detritus, even in areas of upwelling, destroys the relation in summer. There apparently is no simple relation involving daily production and certain significant environmental factors which will allow prediction of daily production in all regions of the ocean during all seasons.
Response of Lobsters Homarus americanus to Odor Solution in the Presence of Bleached Kraft Mill Effluent
Authors: McLeese D. W.
Published: April 2011

The feeding response of lobsters (Homarus americanus) is not affected by bleached kraft mill effluent (BKME) at low concentrations.In test runways, lobsters walked upstream toward the source of dilute solutions of freeze-dried cod muscle extract (FDC). Differences between test and control responses occurred in only two of 12 comparisons when FDC was associated with 10, 50, and 100% BKME (Series I and II). With six concentrations of BKME, ranging from 0.01 to 2.0%, maintained in the runways (Series IV), responses to FDC were variable, but average responses for controls and tests did not differ. Conditions in the latter tests most closely approximated those in nature where some lobsters could be exposed continuously to low concentrations of BKME.
A Comparison of Benthic Microalgal Production Measured by C14 and Oxygen Methods
Authors: Hunding C. , Hargrave B. T.
Published: April 2011

A comparison of estimates of benthic primary production on a sandy beach measured by in situ oxygen and laboratory C14 methods showed that both methods gave similar measures of the magnitude of production. Sources of error in each method are discussed. Measures of C14 uptake offer sensitivity when production is low, but when undisturbed sediment cores can be obtained, production is most easily measured by following changes in dissolved oxygen.
Vers une analyse objective de la thermocline saisonnière
Authors: Boudreault F.-Robert , Laprise J. Pierre
Published: April 2011

We propose a definition of the seasonal thermocline, based on a generalization suggested by Riffenburgh (1970). This allows objective analysis of the thermocline.
Growth and Mortality in an Arctic Intertidal Population of Macoma balthica (Pelecypoda, Tellinidae)
Authors: Green Roger H.
Published: April 2011

In an arctic intertidal environment on Hudson Bay, Macoma balthica have a higher growth rate at a tidal level of 1.1 m above mean low water than at the mean low water level, in terms of both length and dry weight. Temperature, rather than food, appears to be the primary proximate factor involved, and summer air temperatures play a major role. The estimated growth rates are comparable to reported growth rates for intertidal Macoma populations in Scotland and the Netherlands. A partial life table calculated from the death assemblage indicates that Macoma at 1.1 m above mean low water have an annual mortality which increases from about 20% at age 2 to about 50% at age 7 years.
Behavioral Responses to Changes in Hydrostatic Pressure and Light During Larval Development of the Lobster Homarus gammarus
Authors: Ennis G. P.
Published: April 2011

Larvae of the lobster Homarus gammarus hatched and reared under laboratory conditions in shallow water responded to changes in hydrostatic pressure in a depth-regulatory manner. Responsiveness to instantaneous pressure increments ranging from 1 to 20 psi increased linearly and there was no threshold of sensitivity within the range tested. Pressure sensitivity was retained throughout larval life up to and including stage IV (megalopa) but responsiveness weakened with age at least up to stage III. Stage IV larvae were highly responsive to pressure changes but stage V (1st juvenile) lobsters were nonresponsive. Older larvae accommodated to sustained pressure more rapidly than younger larvae and larvae quickly became nonresponsive to repeated pressure changes. After being held at high pressure, larvae responded to slight pressure decreases by downward movement even though still held at pressures to which they would initially respond by vigorous upward movement. Larvae were more responsive to pressure in overhead light than in darkness but light intensity had no apparent effect on the initial response nor on the rate of accommodation to sustained pressure, but in darkness the initial response was slower. Responsiveness to sudden changes in light intensity was much less marked than to pressure changes and it also weakened with age. In the sea older larvae showed a stronger tendency for downward movement when released at the surface and a decreasing tendency for upward movement when released at depths of 25 ft (7.61 m) or more. The average rate of upward movement decreased over a 5-min period and there was no consistent difference in this rate or in the rate at which it decreased when larvae were released at different depths. The average rate of upward movement tended to decrease with age.
Gross Structure of the Adductor Muscles of Some Pelecypods
Authors: Morrison Carol M. , Odense Paul H.
Published: April 2011

A study of the gross structure of adductor muscles of the following pelecypods showed that they conform to Morton’s grouping into the a) "Protobranchia" (Nucula proxima and Yoldia limatula), b) "shallow-burrowing lamellibranchs" (Clinocardium ciliatum, Venericardia borealis, Astarte undata, Arctica islandica, Venus mercenaria, and Spisula solidissima), c) "surface attached lamellibranchs" (Mytilus edulis, Modiolus modiolus, Modiolus demissus, Placopecten magellanicus, and Crassostrea virginica), d) "deep-burrowing and immobile lamellibranchs" (Ensis directus, Hiatella arctica, and Mya arenaria); thus providing more evidence for his classification. The adductor muscle is divided into two portions — translucent and opaque — except in the "deep-burrowing and immobile lamellibranchs", which have opaque muscles only.
First Records of the Gymnoblastic Hydroid, Ichthyocodium sarcotretis, on the Copepod, Sphyrion lumpi, from Redfish of the Northwest Atlantic
Authors: Templeman Wilfred
Published: April 2011

The gymnoblastic colonial hydroid Ichthyocodium sarcotretis was found on the copepod Sphyrion lumpi on redfish from three areas of the northwest Atlantic: on copepods (three of ten) on deepwater redfish (Sebastes mentella) from about 200–500 m over great depths at the mouth of the Labrador Sea and, in bottom otter trawling, on copepods on S. mentella or possibly S. fasciatus from the Labrador Shelf (6 of 686) and the northeast Newfoundland Shelf (1 of 364). None were found on 492 S. lumpi from redfish taken on the continental shelf south and west of the northeast Newfoundland Shelf.The characteristics of the hydroid colonies and of their feeding polyps and reproductive hydranths and medusae are compared with published information on this hydroid found on the same hosts in the Irminger Sea and on the copepod, Sarcotretes scopeli, on the lantern fish, Benthosema glaciale, in the North Atlantic. The incidence of the hydroid on S. lumpi on redfish may possibly help in distinguishing Sebastes species in the northwest Atlantic.
Behavior of Adult American Shad (Alosa sapidissima) Homing to the Connecticut River from Long Island Sound
Authors: Dodson Julian J. , Leggett William C.
Published: April 2011

The migratory behavior of American shad (Alosa sapidissima) approaching their natal river during the final saltwater stage of the spawning migration was studied using ultrasonic tracking and conventional tagging procedures. Initial displacement of most sonic-tagged shad released without displacement adjacent to and 10 km west of the Connecticut River was not in the direction of the home river. These fish, however, homed successfully to the Connecticut River as did dart-tagged shad released in the same areas.Shad exhibited two major behavior patterns; countercurrent orientation in response to the reversing tidal current and adjustment of swimming speed to changes in tidal velocity. Countercurrent orientation was equally significant during daylight and darkness, whereas the adjustment of swimming speeds to tidal current velocity was more significant during daylight than darkness.Shad tracked to the west exhibited a westerly bias inherent in the basic open water behavior patterns. Shad exhibited a greater degree of directed movement when oriented against the ebb tide and adjusted their swimming speeds to exceed the ebb tide velocity and to approximately equal the flood tide velocity. Shad tracked to the east exhibited the same major behavior patterns but with the opposite directional bias.A hypothesis is presented suggesting that the location of the home river is achieved by means of a nonrandom search. Environmental clues indicative of the Connecticut River act to establish a preferred direction of displacement while the actual unidirectional displacement is achieved by reference to the rate and direction of tidal currents.
Management of Multiple Resources
Authors: Garrod D. J.
Published: April 2011

From the point of view of the exploiting industry, fisheries can be classified according to the breadth of its resource base, varying from single-species fisheries to integrated multiple-resource fisheries.All resources exhibit short-term fluctuations, which in the multiple-resource fishery necessarily lead to differential rates of exploitation of the component resources.The differential rates of exploitation in the components of a multiple resource, even by aimed activity of the same vessels, imply nonequilibrium conditions in the individual stocks. This contrasts with the basic objective of conventional stock assessments to establish yield under equilibrium conditions.A technique of investigating and comparing yield from resources in equilibrium or nonequilibrium is illustrated with reference to North Atlantic cod, the "equilibrium" fishery being one in which the distribution of fishing is independent of stock density, whereas the nonequilibrium characteristics of a multiple-resource base are associated with a distribution of fishing mortality weighted by the density of the component resources.Provided fishing mortality varies about an appropriate mean level, there is no marked difference in yield under equilibrium or nonequilibrium conditions. Fisheries are robust systems which can tolerate wide between-year variations in fishing mortality provided it fluctuates around an appropriate mean level. This implies that there is no advantage in trying to manage a fishery by a precise control of fishing mortality.Under certain circumstances, determined by the variability of the particular resource complex, a density-dependent regime of exploitation may be a more efficient method of exploitation of a given array of resources. This has the additional advantages of reducing the year-to-year variation in yield to the total fishery and of reducing the risk of overexploitation in cases where catchability can be expected to be inversely proportional to stock abundance.
Reconciling Conflicts among Different Economic Interest Groups in the Management of Fisheries
Authors: MacKenzie W. C.
Published: April 2011

It is argued that the combined interests of consumers, producers, and the public are best served if the benefits from and the costs of using available fishery resources are calculated in social terms. An optimal level of productive inputs to a fishery can be approached through the imposition of appropriate controls by the state. The form that such action might take in the case of established fisheries, particularly, is considered and the need for gradual and flexible implementation, to prevent industrial and social disruption, is stressed.Management of international fisheries is complicated by the fact that the social optimum, which serves to provide a rational objective for one country, is indeterminate when fish stocks are exploited by fleets of several nations. A second-best arrangement, which would permit the purchase of inputs from the least costly sources and the sale of products in the markets where prices are highest, with the net proceeds being distributed among countries on the basis of need, seems to be impracticable in the foreseeable future. The conclusion is drawn that, for the present, a system of annual catch quotas allocated among interested countries may offer a reasonable solution to the problem.The difficulties associated with the setting of quotas and their equitable allocation are discussed in some detail and the conflicts of interest that may arise in the process are indicated, e.g. those relating to variation in national time-preferences, to differences in stages of development, and to the accommodation of new entrants. Reference is made, in particular, to the conflict between the short-run interests of states with mobile (distant-water) fleets and those of coastal states. Some possibilities for the reconciliation of these conflicts are suggested, e.g. quota-share trading, compensation for abstention, and exchange of (fleet and port) services.
Objectives and Methods of Small-Scale Fisheries Development
Authors: Proude P. D.
Published: April 2011

Governments in industrialized as well as developing countries have adopted policies of assistance for small-scale fishermen. These may be conceived within the framework of social assistance or of purely economic development, but in either case the actions taken need to conform to long-range planning. Care should be taken to see that small-scale fisheries will have a continuing resource base and will complement rather than be in conflict with the activities of large fishing vessels, where the latter exist. In developing countries the objectives and methods used to stimulate the small-scale sector are more varied than in industrialized countries. In the latter, action has been focused mainly on loans and subsidies for modernization of equipment and provision of dock facilities. Less often, roads and even townsites have had to be developed. In developing countries all these may be needed, and they start from a much lower base in terms of equipment and mechanical skill. In addition there is a need for developing marketing facilities, ice plants and refrigeration at major centers, and also training programs, not only for fishermen but also for ancillary services, especially motor mechanics. Frequently the organization of cooperatives is the means by which some or all of these measures are attempted, but here too the necessary managerial skills take time to develop.
Problems Confronting Fishing Industries Relative to Management Policies Adopted by Governments
Authors: Elliot G. H.
Published: April 2011

With increase in numbers, size, and effectiveness, fishing fleets have depleted important stocks of fish, and strong international action by governments is imperative for the future viability of fishery resources. The author favors a system of an overall quota of fish, with individual quotas for boats and plants, and predicts that this will become "the accepted method of running fisheries" in 20 years. He discusses how best to organize such a system, with full consultation between governments and their national fishing industries as well as at the international level. For efficient handling of the complex issues involved and a full understanding of them, he suggests that governments should appoint to their fisheries ministries officers who have specialized in fisheries management and are able to analyze the situation in depth and advise the administrators on the implications of alternative management policies. The controls over fishing that he advocates are essential because "free fish means eventually no fish."
Recent Limnological Studies of Okanagan Basin Lakes and their Contribution to Comprehensive Water Resource Planning
Authors: Stockner J. G. , Northcote T. G.
Published: April 2011

Results of limnological investigations of Okanagan mainstem and headwater lakes are reviewed in relation to their input to studies of comprehensive water resource management in the Okanagan Valley, British Columbia. The current trophic state of the lakes is discussed on the basis of our understanding of their current condition and areal annual loads of total phosphorus. The practical usefulness of limnological data in this multidisciplinary study is reviewed, and specific investigations are discussed in relation to their essential and nonessential components, and how these have or have not contributed to the development of management strategies. The role of limnologists in this type of applied study is discussed and their cooperation in similar types of studies is encouraged.
Olfactory Response and Fenitrothion Toxicity in American Lobsters (Homarus americanus)
Authors: McLeese D. W.
Published: April 2011

In test runways the olfactory response of American lobsters (Homarus americanus) to cod muscle extract is not affected by simultaneous presentation of fenitrothion at measured concentrations ranging from 0.05 to 25.4 ppb at time of stimulation.Larval and adult lobsters have similar sensitivity to fenitrothion. For both, the 96-h LC50 is about 1 ppb. The lethal threshold for larvae is about 0.015 ppb, that for adults is 0.3 ppb or lower.
Natural Mortality Rate in Last Winter of Life of Coho Salmon (Oncorhynchus kisutch) Resident in Puget Sound
Authors: Mathews Stephen B. , Buckley Raymond
Published: April 2011

The natural mortality rate during a 3.5-mo period of the last year of life of coho salmon (Oncorhynchus kisutch) resident in Puget Sound was estimated to be 48% of the population at the beginning of this period. This estimate was based on recaptures of 29 fish out of 169, averaging 32 cm in fork length, tagged in January and early February, and 20 out of 61 averaging 41 cm tagged in May and early June, 1970.
A Syringe Volumetric Measuring Device
Authors: Myers G. L. , Peterka J. J.
Published: April 2011

A volumetric measuring device, constructed from a hypodermic syringe and the graduated cylinder of a burette, were described. Steel spheres were measured more accurately and precisely with the device than with graduated cylinders. For spheres of three sizes, the percent deviations of the means of measured volumes ranged from 0.3 to 0.8% in comparison with 0.6–13.1% for graduated cylinders and the standard errors of the means, from 0.007 to 0.011 ml in comparison with 0.029–0.070 ml.