摘要:

Phytoplankton production and distribution were examined over a 2-yr period in the Burrard Inlet system, which includes a true fiord (Indian Arm), a shallow blind inlet (Port Moody Arm), and a turbulent narrows region that is contiguous to the Port of Vancouver. Greatest annual production occurred in Port Moody Arm with a mean of 532 g C∙m−2∙yr−1while the lowest values were in Indian Arm and the Narrows region, averaging about 260 g C∙m−2∙yr−1. Nitrate and zooplankton grazing were the main factors limiting phytoplankton production in Indian Arm, while flushing and poor light conditions influenced phytoplankton growth in the Narrows and outer Burrard Inlet. Most of the discharges of domestic and industrial wastes have been diverted to the Fraser River, and Vancouver Harbor can be considered relatively clean and pollution-free because of strong tidal mixing and seaward flushing. The only sign of eutrophication in the inlet is in Port Moody Arm where sufficient nutrients from sewage discharges and a relatively stable mixed-layer depth create near optimal conditions for phytoplankton growth. Daily production here is among the highest recorded in the literature for Pacific coastal marine waters.Key words: Phytoplankton, primary production, coastal marine embayment, fiord, phytoplankton succession and distribution, chlo

ISSN:0706-652X    

DOI:10.1139/f79-001

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Most apparatus designed to detect avoidance of pollutants by aquatic organisms require visual observations of test organisms in steep pollutant gradients. AGARS (Aquatic Gradient Avoidance Response System) was developed to eliminate these limitations. This system allows animals to choose between one uncontaminated zone and three increasingly toxic zones in a gradient trough that is monitored for extended time periods by infrared light sources, sensors, and a microprocessor. Data are accumulated hourly and processed by a paper tape reader/calculator/plotter system that records the time test animals remain in each zone and compares behavior before and during test exposures. Initial tests indicate that pinfish (Lagodon rhomboides) tested in the apparatus will avoid chlorine-produced oxidants at concentrations of 0.02–0.04 mg/L.Key words: avoidance responses, behavioral bioassays, automated monitoring systems, chlorine-produced oxidants

ISSN:0706-652X    

DOI:10.1139/f79-002

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Field and laboratory studies were conducted to characterize concentrations, factors determining concentrations, particle size composition, and presumed food quality of particulate organic matter (POM) transported by streams of four different orders in Oregon's Cascade Mountains. Devils Club Creek (first order) and Mack Creek (third order) as high gradient, heavily shaded headwater streams receive large amounts of forest debris. Lookout Creek (fifth order) and the McKenzie River (seventh order) have lower gradients and more organic inputs from in situ aquatic primary producers and organic matter drifting from upstream areas than from the adjacent forest. Concentration of particulate organic matter is low during periods of nonstorm discharge, and not significantly related to stream power or type of organic input. All streams transport a mean POM particle size < 12 μm. Over 70% of all particulate organic matter transported is very fine particulate organic matter (VPOM: 0.45–53 μm). Except for spring, the ratio of coarse (> 1 mm) to fine (0.45 μm–1 mm) organic matter (CPOM:FPOM) is near zero, but remains elevated for the McKenzie River during all seasons. As determined by the amount of chlorophyll, carbon to nitrogen (C:N) ratio, percentage of organic matter and respiration rate, the presumed food quality of drifting organic matter is potentially better in downstream reaches.Key words: food quality, detritus, organic matter, streams, rivers, watershed, drift, transport

ISSN:0706-652X    

DOI:10.1139/f79-003

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The paralytic shellfish poison of the giant sea scallop,Placopecten magellanicus(Gmelin), from the Bay of Fundy has been analyzed. Of eight toxins isolated, seven were identified with those previously recognized in various sources including the Atlantic toxic dinoflagellate,Gonyaulax tamarensiscells. The major components were gonyautoxin-I, gonyautoxin-II, and neosaxitoxin; saxitoxin was responsible for only a very small portion of the total toxicity. A minor toxin that was eluted between neosaxitoxin and saxitoxin in the chromatography system was found to be new and designated as gonyautoxin-VII.Key words: paralytic shellfish poisons, gonyautoxins, neosaxitoxin,Gonyaulax tamarensis

ISSN:0706-652X    

DOI:10.1139/f79-004

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Larval fish were sampled by net in Lake Huron and the Douglas Point generating station throughout spring, summer, and early fall 1975. Dominance shifted from fourhorn sculpin (Myoxocephalus quadricornis) to rainbow smelt (Osmerus mordax) then to ale-wife (Alosa pseudoharengus) from late April to late September. Entrainment of the major species paralleled dominance and abundance observed in the lake, but yellow perch (Perca flavescens), brook stickleback (Eucalia inconstans), and slimy sculpin (Cottus cognatus) caught in the lake — each ranging from 5 to 25% of the total catch — were not entrained. Conversely, white sucker (Catostomus commersoni) was entrained but not captured in the lake. Size of individuals entrained, upper limit approx. 40 mm, paralleled size of individuals in the lake. Vertical distribution, and thus proximity to the submerged intake, greatly influenced entrainment rate.Key words: larval fish, entrainment, power plant, distribution, abundance.

ISSN:0706-652X    

DOI:10.1139/f79-005

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Evidence is presented showing that the deep waters in the Saguenay Fjord are flushed at a rate that appears to be significantly higher than other sill fjords with comparable bathymetry. Interval waves in the St. Lawrence estuary, with magnitudes of up to 60 m, provide a mechanism for bringing up dense water, semidiurnally, to the level of the seaward sill. Providing the density of the deep water in the fjord's outer basin is less than that at sill depth, a density flow develops and descends into the basin. Estimates of volume and kinetic energy fluxes of the plume suggest that, by itself, this is insufficient to explain the high flushing rates observed. Other processes, such as internal waves, which must be operative in carrying energy into the deep basin, are discussed.Key words: estuaries, sill fjords, mixing, circulation, coastal

ISSN:0706-652X    

DOI:10.1139/f79-006

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Atlantic Coast striped bass (Morone saxatilis) commercial fisheries data are examined for periodicities in the appearance of dominant year-classes using autocorrelation and spectral-analysis techniques. Results obtained using maximum entropy and classical Fourier spectral-analysis methods are compared. Statistically significant periodicities of approximately 20 yr and of 6–8 yr are common to the time series for most states and regions. Since the periodicities are neither very pronounced nor simple, it is difficult to isolate the causative factors, which are more likely to be density-independent environmental factors enhancing survival of the young than intrinsic characteristics of the life cycle of striped bass. The spectra for Maryland landings and Maryland landings per unit gear are nearly identical, suggesting that at least for Maryland the landings and landings-per-unit-gear data are approximately equally reliable as indices of stock size. The structure of the North Carolina time series is unique, which supports the opinion that this stock does not mix appreciably with Chesapeake and Hudson stocks. Impact assessments and monitoring programs should not be predicted on the expectation of pronounced or simple periodicities of 6 years or any other time interval in the appearance of dominant year-classes in Atlantic Coast striped bass populations.Key words: autocorrelation analysis, commercial fisheries data, Fourier spectral analysis, maximum entropy spectral analysis, periodicities, striped bass

ISSN:0706-652X    

DOI:10.1139/f79-007

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The upstream orientation and frequency of upstream movement of ripe male rainbow trout (Salmo gairdneri) in the presence of ovarian fluid obtained from spawning females of the same species were observed and quantified. In a stream tank, male trout moved upstream in the ovarian fluid odor plume. In an optomotor tank, male trout exhibited an increase in the frequency of upstream orientation and movement in the presence of diffuse, nondirectional ovarian fluid. It is concluded that water currents provide directional cues and olfactory stimuli regulate the orientational and kinetic components of the rheotropic response. The significance of this mechanism of orientation in fish migration is discussed.Key words: rheotropism, behavior, olfaction, orientation, migration, ovarian fluid

ISSN:0706-652X    

DOI:10.1139/f79-008

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Total vertebral counts ofLycodapus mandibularispopulations in Georgia Strait, British Columbia, are significantly lower than those of southern populations off Oregon and California. The highest temperatures and lowest salinities at 200 m or deeper, where the species is most abundant, are also in Georgia Strait and correlate with the lowest counts. The Strait's deep water originates from tidal mixing of intermediate and estuarine surface waters of lower salinities and higher temperatures, whereas the mechanism in southern latitudes, which instead provides unmixed cooler and saline deep waters, is oceanic up-welling. It is suggested that differences in environment associated with different degrees of upwelling and mixing may cause the lower counts in the Strait of Georgia.Key words:Lycodapus mandibularis, Zoarcidae, meristic variation, inlets, upwelling, temperature, salinity, northeast Pacific Ocean, zoogeography

ISSN:0706-652X    

DOI:10.1139/f79-009

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Fingerling rainbow trout (Salmo gairdneri) fed tubificid worms (Tubifexsp.) grew faster than those fed Oregon Moist Pellets (OMP) over a similar range of rations. Faster growth resulted because trout incorporated protein and fat from tubificids more efficiently than from OMP. Exposure to a sublethal concentration of dieldrin in water (0.18 μg/L) did not affect the protein elaboration of trout fed either diet or fat metabolism in trout fed OMP. However, dieldrin reduced fat elaboration in trout fed tubificids. The dieldrin concentrations in trout exposed to dieldrin in water increased as feeding level (and therefore body fat) increased. The different responses to dieldrin by fish fed these two diets provides evidence that the diet offered to fish can significantly influence the outcome of chronic toxicity tests.Key words: Rainbow trout, tubificid worms, Oregon Moist Pellets, dieldrin, growth, fat metabolism

ISSN:0706-652X    

DOI:10.1139/f79-010

出版商:NRC Research Press    

年代:1979

数据来源: NRC