摘要:

Continuous horizontal profiles of chlorophyll, temperature, salinity, and oxygen were made at three depths and in three locations in British Columbia coastal waters, and spectra and cross spectra calculated. Generally, fairly strong relationships exist between chlorophyll and temperature and salinity, especially at scales of order 10–1000 m. However, the relationships are not always expressed through the same physical parameter. It is apparent from coherence and phase data that in a turbulent environment the vertical profiles of the parameters are important in determining the nature of the relationships. Average spectra show power law relationships similar to the results of other authors.Key words: chlorophyll, temperature, salinity, oxygen fluctuations; surface coastal waters; T, S, O2, chlorophyll fluctuations; spectra and cross-spectra of T, S, O2, chlorophyll; measurements of T, S, O2, chlorophyll in surface waters

ISSN:0706-652X    

DOI:10.1139/f79-020

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The general pattern of nutrient distribution in the Gulf of St. Lawrence results from regeneration processes being superimposed on the physical processes of estuarine circulation within the Gulf. This leads to a general increase in nutrient concentration with depth and with distance into the Gulf from Cabot Strait. Nutrient concentrations in the Laurentian Channel are higher inside the Gulf than at equal or even greater depths in the Atlantic Ocean some distance outside Cabot Strait. Summer nutrient concentrations in the surface layer are generally low. However, during the winter when biological activity is low, quite high concentrations of the nutrients are found in the surface waters of the Gulf. A balance exists between inward and outward fluxes of all three nutrients through Cabot Strait in the winter. However, in the summer the influxes of both nitrate and silicate at Cabot Strait greatly exceed the outgoing fluxes. Losses of biogenic silica to the sediments may account for the silicate imbalance. Excess nitrate may be accounted for if ammonia or nitrogen bound with dissolved organics had been measured.Key words: nutrients, silicate, phosphate, nitrate, distribution, regeneration, transport, Gulf of St. Lawrence, Cabot Strait, Laurentian Channel

ISSN:0706-652X    

DOI:10.1139/f79-021

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Smolt production at different egg deposition densities is estimated from data on survival rates and space requirements of juvenile Atlantic salmon (Salmo salar) reported in the literature. Average maximum production of smolts is estimated to be approximately 5/100 m2for 2+ smolts, 2/100 m2for 3+ smolts, and 1/100 m2for 4+ smolts. Minimum egg depositions recommended for production of these numbers of smolts are 220/100 m2, 165–220/100 m2, and 80/100 m2for each age of smolts, respectively. The escapement of adults required to produce these depositions must be estimated from observed average weights of returning females and a reported fecundity of Atlantic salmon between 1650 and 1760 eggs/kg of female. With the exception of Ungava rivers, average smolt age in any particular river can be estimated from the number of days per year on which water temperature reaches or exceeds 7 °C.Key words: fishery resources, fishery management, production (biological), escapement, survival, game fish, freshwater fish, rivers

ISSN:0706-652X    

DOI:10.1139/f79-022

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Ages determined for older Pacific hake from sections through the nucleus of otoliths were older than the ages determined from the otolith surface for the two populations studied. Growth of all parts of the otolith was not identical throughout the life of the fish. The change in the pattern of otolith growth occurred about the age at which the growth in length of the fish was reduced. Despite the disproportionate growth in length and height of the otolith, the thickness of the otolith, especially in the ventral interior portion, continued to increase with age. Section ages appear to be more reliable for older fish because of this allometric change in otolith growth with increasing fish age. It is suggested that the examination of sections of otoliths should become a routine approach in any attempt to age fish using otoliths.Key words: age determination, otolith, otolith section, otolith growth, aging errors, Pacific hake, Strait of Georgia

ISSN:0706-652X    

DOI:10.1139/f79-023

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A simplified chlorophyll analytical procedure is described that requires 4 min/sample and features an overall precision (measured by the coefficient of variation, C.V.) of ~ 3% at the 15 mg/m3chlorophyllalevel. The C.V. varies inversely with concentration for spectrophotometric determinations. The molar extinction coefficients (665 nm) for chlorophyllawere estimated to be 2.5–6.0% greater in acetone (90%) compared to methanol (100%) and 2.5% greater in a 1:1 mixture (v/v) of methanol-dimethyl formamide compared to methanol. Acetone (90%) extractions of naturally occurring mixtures of the common bloom-forming blue-green algaeMicrocystis,Oscillatoria,Aphanizomenon, andAnabaenayielded erratic recoveries of chlorophylla. The lowest recovery (34%) occurred with anOscillatoriapopulation. On the one occasion when a four-way solvent extraction comparison was performed, acetone (90%) failed to extract 29 ± 2% of the chlorophyllain a mixture ofAnabaena,Microcystis, andAphanizomenon, whereas the other three solvent preparations yielded identical (complete) extractions. Methanol or acetone-dimethyl sulfoxide are recommended for chlorophyll extraction from blue-green algae, while acetone-dimethyl sulfoxide is recommended for diatoms or Chlorophyta populations.Key words: chlorophyll, Cyanophyta, Chlorophyta, chlorophyll analysis, methanol, acetone, methanol-dimethyl formamide, acetone-dimethyl sulfoxide

ISSN:0706-652X    

DOI:10.1139/f79-024

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Tissue activities of alanine aminotransferase (AlAT), aspartate aminotransferase (AspAT), sorbitol dehydrogenase (SDH), gamma glutamyl transferase (GGT), alkaline phosphatase (ALP), and creatine kinase (CK) were determined in three cetacean species: the bottlenosed dolphin,Tursiops truncatus, beluga whale,Delphinapterus leucas, and harbor porpoise,Phocoena phocoena. Liver was the principal source of AlAT and SDH activity; GGT and ALP were concentrated in kidney. Muscle tissues showed the highest CK and AspAT activity, although most other tissues had appreciable AspAT activity. Based on tissue specificity, plasma AlAT and SDH are recommended for use in diagnosing hepatic disorders. Plasma GGT may have potential value in assessing the type of hepatobiliary damage caused by trematodes in cetaceans; ALP has no obvious advantage over GGT. Creatine kinase elevations in plasma would indicate muscle damage or exercise stress, while plasma AspAT may reflect either muscle or liver release and must be used in conjunction with other more tissue-specific enzymes. Reference plasma enzyme activities determined in healthy captiveT.truncatusshowed significant procedure-related differences that must be considered when circulating enzymes are used in research or diagnosis.Key words: enzymes, tissues, plasma, Cetacea, stress

ISSN:0706-652X    

DOI:10.1139/f79-025

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Various models have been proposed to predict the combined interactive effect on fish of mixtures of poisons from separate toxicities of individual substances. The success of these models was tested, using data describing the lethal and sublethal effects of individual substances or binary mixtures of HCN and Cr(VI), Zn(II), or ammonia to the fathead minnow (Pimephales promelas) and rainbow trout (Salmo gairdneri). Using the strictly additive toxic unit and additive index approach, it was determined from log-dosage mortality curves that the Zn–HCN and ammonia–HCN mixtures were more acutely toxic and Cr–HCN less toxic than predicted. The concentration and response addition models, which have been proposed for toxicants whose joint action is similar or independent, respectively, could not be used to predict dosage–mortality curves for the HCN mixtures. Linear regression lines representing the growth response of fish to log concentration for toxicants alone and in binary combinations were not significantly different. Thus, for the toxic substances tested, the sublethal joint action of individual toxicants was not predictable from existing models and, in most cases, no interaction was indicated. The interactive nature of toxicants may be a function of the concentrations tested causing different biological processes to be affected (e.g. mortality vs. growth), and therefore different responses to be measured. A need still exists for development of a valid multiple toxicity approach for evaluating and predicting the toxicity of chemical combinations.Key words: multiple toxicity, binary mixtures, joint action, fish, bioassay, toxic substances

ISSN:0706-652X    

DOI:10.1139/f79-026

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Underwater observations were made on the diel activity patterns of yellow perch (Perca flavescens) in Cazenovia Lake, Madison County, New York (42°56′N, 75°52′W). Perch underwent a characteristic progression of activities during dusk at relatively predictable light levels and times. Patterns within the progression included increased swimming, last feed, group breakup, slowdown, and final stop. Activity at sunrise was the reverse of the sunset sequence except that some activities occurred at lower light levels than did the analagous activities in the evening. Differences exist in the twilight activity patterns of perch in different lakes; within a lake, both ontogenetic and subpopulation differences are also observed. These differences may be responses to ecological conditions, such as relative predation levels, or they may reflect the extreme plasticity of the species.Key words: behavioral ecology, changeover, diel, diurnal, fish, light, nocturnal, ontogeny, plasticity, temperate lake

ISSN:0706-652X    

DOI:10.1139/f79-027

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

An attempt has been made to evaluate the accuracy of ATP as a measure of living phytoplankton carbon in estuaries. Phytoplankton carbon estimated from ATP was compared to estimates from cell counts. In high biomass samples the agreement between the two estimates was quite good. In the low biomass samples the cell count method underestimated phytoplankton carbon relative to the ATP estimate. This was interpreted to be due in part to low cell counts in these samples. Contamination by microzooplankton (essentially only tintinnids) was, in 14 out of the 18 samples, < 3% of the ATP estimated carbon. However, it was as high as 19% in one case. In the lowest biomass samples (< 0.5 μg chlorophylla/L) bacterial populations may contribute as much as 50% of the total living carbon. It is concluded that, with caution, ATP is a useful measure of living phytoplankton carbon in estuaries during periods of moderate to high biomass (> 1 μg chlorophylla/L for the St. Lawrence). Since carbon to chlorophyll ratios in the high biomass samples varied considerably, a constant ratio appears inapplicable for transforming chlorophyll to carbon.Key words: ATP, phytoplankton biomass, estuaries, carbon to chlorophyll ratio

ISSN:0706-652X    

DOI:10.1139/f79-028

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Two transects, north–south and east–west, through the Anticosti gyre and the Gaspé current were sampled for physical properties, nutrient and plankton concentrations over a 5-d period during July 1976. Temperature, salinity, σtand nutrient isolines formed a dome characteristic of cyclonic circulation with the apex within the Anticosti gyre, but a strong shallow thermocline prevented nutrient enrichment of the surface mixed layer. Surface nitrate and silicate concentrations were very low, except for two anomalies, throughout the region sampled, with phosphate concentrations higher. Phytoplankton biomass was uniformly low and dominated by nannoplankton (< 15 μm) at all stations except that in the Gaspé current at which netplankton (15–202 μm) was important and the total biomass considerably higher. The higher biomass and importance of larger celled species suggest higher nutrient turnover in the Gaspé current.Nitzschia delicatissimadominated the species composition in the Gaspé current, dinoflagellates and microflagellates being of more importance within the gyre and along the north shore. Zooplankton biomass was distributed fairly uniformly over the entire region but species composition at the shallower stations was characterized by small copepod species (Pseudocalanussp.,Acartiasp.) and fish larvae, the gyre stations being characterized by larger copepod species (Calanussp.), euphausids, and decapod larvae. Physical properties, nutrients, and plankton were distributed quite uniformly except for the marked variability in the measurements made in the strongly advective Gaspé current station. Distributions of derived parameters that were estimated at 5 m depth suggest nutrient limitation at most stations within the gyre, with the exception of the two stations at which surface nutrient anomalies were detected, while at the nearshore stations, in the Gaspé current and along the north shore, better physiological state and lack of nutrient limitation were observed. Short-term variability in these parameters complicate geographic interpretation, but trends were discernable. Estimated daily primary production was an order of magnitude less than that reported previously.Key words: Anticosti gyre, Gaspé current, primary production, nutrient limited growth

ISSN:0706-652X    

DOI:10.1139/f79-029

出版商:NRC Research Press    

年代:1979

数据来源: NRC