Diet and feeding of Neomysis mercedis Holmes (Crustacea, Mysidacea) from the Fraser River Estuary, British Columbia

1982 ◽  
Vol 60 (5) ◽  
pp. 813-824 ◽  
Author(s):  
N. T. Johnston ◽  
D. C. Lasenby
Keyword(s):  
Body Size ◽  
Consumption Rate ◽  
Ingestion Rate ◽  
River Estuary ◽  
Dry Weight ◽  
Fraser River ◽  
Organic Fraction ◽  
Biological Origin ◽  
Seasonal Differences ◽  
Harpacticoid Copepods

Neomysis mercedis in the Fraser River estuary is a predator on the meiobenthos, especially harpacticoid copepods. There are no clear seasonal differences in its utilization of food resources. The consumption rate of N. mercedis feeding from natural sediments varies with body size and temperature as C = 3.81 W0.782T0.515, where C is the consumption rate of meiofauna in micrograms dry weight per animal per hour, W is the mysid size in milligrams dry weight, and T is the temperature in degrees Celsius. The weight dependence of the ingestion rate is identical to that of the metabolic rate but the temperature dependence is significantly lower. The mysid selectively feeds on the organic fraction of the sediments but only one-half of the ingested material (by weight) is of biological origin. In mid-April, mysid predation may result in a 12% per day mortality rate on harpacticoid copepods. Thus, mysid predation may strongly influence meiofaunal densities.

Growth and reproduction of Macoma balthica (L.) on a mud flat in the Fraser River estuary, British Columbia

1983 ◽  
Vol 61 (4) ◽  
pp. 887-894 ◽  
Author(s):  
E. R. McGreer
Keyword(s):  
Growth Rate ◽  
British Columbia ◽  
Shell Height ◽  
Macoma Balthica ◽  
River Estuary ◽  
Dry Weight ◽  
Maximum Growth ◽  
Fraser River ◽  
Mud Flat ◽  
Growth And Reproduction

Growth and reproduction of the bivalve, Macoma balthica (Linnaeus, 1758) was studied for one year (April 1977 – March 1978) on an intertidal mud flat in the Fraser River estuary, British Columbia. The maximum number of individuals (1830/m2) occurred in April, then steadily declined throughout the year. Spawning occurred between mid-June and late July but recruitment was slow and prolonged. Peak spatfall (age 0+ individuals) did not occur until the following March when a maximum density of only 410/m2 for newly settled spat was observed. The oldest animals found were 5+ years of age. Maximum growth took place from April through July. The growth rate measured was one of the highest recorded for any M. balthica population. A direct relationship between high water temperatures, a fast growth rate, and reduced longevity was apparent. A regression of body weight on shell height was used to calculate a condition factor (CF), which reached its highest value during growth and its lowest value immediately after spawning. The mean annual biomass measured was 2.96 g dry weight per square metre.

Life-history variation in Neomysis mercedis Holmes (Crustacea, Mysidacea) in the Fraser River estuary, British Columbia

1989 ◽  
Vol 67 (2) ◽  
pp. 363-372 ◽  
Author(s):  
N. T. Johnston ◽  
T. G. Northcote
Keyword(s):  
Life History ◽  
Body Size ◽  
River Estuary ◽  
Mortality Rates ◽  
Tidal Marshes ◽  
Adult Size ◽  
Fraser River ◽  
Life History Variation ◽  
Adult Body Size ◽  
Adult Body

The brackish-water mysid Neomysis mercedis in tidal marshes of the Fraser River produced overwintering and summer generations that differed in life-history traits. Summer generation females matured at a smaller size and produced fewer and larger eggs than the overwintering generation. Size-adjusted clutch weights were identical for summer and overwintering females. Reproductive effort was slightly lower for the overwintering females. Both generations were iteroparous, but the average frequency of breeding was higher for the overwintering generation. Seasonal variations in reproductive traits were strongly linked to fluctuations in the relative mortality rates of neonates and adults. Overwintering adults that bred in late spring had lower mortality rates than neonates, while mortality rates for summer adults were higher than those for neonates. Rearing suggested that changes in adult body size were a phenotypic response to temperature. Food availability had little additional effect on adult body size. A positive correlation between ambient water temperatures and the increase in mortality with increasing adult size provided a possible mechanism through which temperature-dependent phenotypic variation in adult body size could be selected.

Sources of Chlorophenolic Compounds to the Fraser River Estuary

1988 ◽  
Vol 23 (1) ◽  
pp. 55-68 ◽  
Author(s):  
J. H. Carey ◽  
J. H. Hart
Keyword(s):  
River Flow ◽  
River Estuary ◽  
Low Flow ◽  
Fraser River ◽  
Pulp Mills ◽  
Flow Conditions ◽  
Downstream Site ◽  
Upstream Site ◽  
The North ◽  
Main River

Abstract The identity and concentrations of chlorophenolic compounds in the Fraser River estuary were determined under conditions of high and low river flow at three sites: a site upstream from the trifurcation and at downstream sites for each main river arm. Major chlorophenolics present under both flow regimes were 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), pentachlorophenol (PCP), tetrachloroguaiacol (TeCG) and a compound tentatively identified as 3,4,5-trichloroguaiacol (3,4,5-TCG). Under high flow conditions, concentrations of the guaiacols were higher than any of the Chlorophenols and concentrations of all five chlorophenolics appeared to correlate. Under low flow conditions, concentrations of chloroguaiacols were higher than Chlorophenols at the upstream site and at the downstream site on the Main Arm, whereas at the downstream site on the North Arm, concentrations of 2,3,4,6-TeCP and PCP were higher than the chloroguaiacols in some samples. Overall, the results indicate that pulp mills upstream from the estuary are important sources of chlorophenolics to the estuary under all flow conditions. Additional episodic inputs of 2,3,4,6-TeCP and PCP from lumber mills occur along the North Arm. When these inputs occur, they can cause the concentrations of Chlorophenols in the North Arm to exceed provisional objectives. If chloroguaiacols are included as part of the objective, concentrations of total chlorophenolics in water entering the estuary can approach and exceed these objectives, especially under low flow conditions.

Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments of the Brisbane River (Australia) – Preliminary Results

1989 ◽  
Vol 21 (2) ◽  
pp. 161-165 ◽  
Author(s):  
S. I. Kayal ◽  
D. W. Connell
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
River Estuary ◽  
Dry Weight ◽  
Weight Basis ◽  
Sediment Samples ◽  
Preliminary Results ◽  
Treated Sewage ◽  
Polycyclic Aromatic ◽  
Petroleum Refineries

Results of the analysis of twenty-three composite sediment samples revealed that PAHs are widely distributed in the Brisbane River estuary. Mean concentrations for individual compounds, on a dry weight basis, ranged from 0.03 µg/g for dibenz [ah] anthracene to 2.34 µg/g for fluoranthene. Observed PAH assemblages were rich in compounds having pyrolytic origins. However, the presence of petroleum derived compounds was indicative of the importance of petroleum as a PAH source in the estuary. Petroleum refineries, a coal loading terminal and a major treated sewage outfall located at the mouth were not indicated as major contributing sources of PAH pollution in the estuary.

scholarly journals SITE FIDELITY AND LOCAL MOVEMENTS OF MIGRATING WESTERN SANDPIPERS ON THE FRASER RIVER ESTUARY

2002 ◽  
Vol 114 (4) ◽  
pp. 485-490 ◽  
Author(s):  
ROBERT W. BUTLER ◽  
PHILIPPA C. F. SHEPHERD ◽  
MOIRA J. F. LEMON
Keyword(s):  
Site Fidelity ◽  
River Estuary ◽  
Fraser River ◽  
Western Sandpipers

The Oxygen Consumption of an Echiuroid, Bonellia Viridis Rolando

1968 ◽  
Vol 48 (2) ◽  
pp. 427-434
Author(s):  
A. E. BRAFIELD
Keyword(s):  
Oxygen Consumption ◽  
Body Size ◽  
Continuous Flow ◽  
Muscular Activity ◽  
Dry Weight ◽  
The Body ◽  
Body Region ◽  
Rate Of Oxygen Consumption

1. The oxygen consumption of the echiuroid Bonellia viridis has been investigated by means of a continuous-flow polarographic respirometer. 2. The general rate of oxygen consumption per unit dry weight is similar to that characteristic of polychaetes, and declines exponentially with increasing body size. 3. The rate of oxygen consumption rises in the light and falls again if darkness is restored. 4. The oxygen consumption of the isolated proboscis plus that of the isolated body region corresponds closely to that of the entire animal. 5. The oxygen consumption per unit dry weight of the proboscis is considerably higher than that of the body region. 6. The oxygen consumption of an isolated body region increases in the presence of light, but that of an isolated proboscis does not. 7. These findings are discussed in relation to the biology of the animal, observed muscular activity, and the occurrence of the pigment bonellin.

The Relation of Oxygen Consumption to Body Size and to Temperature in the Larvae of Chironomus Riparius Meigen

1958 ◽  
Vol 35 (2) ◽  
pp. 383-395
Author(s):  
R. W. EDWARDS
Keyword(s):  
Oxygen Consumption ◽  
Body Size ◽  
Dry Matter ◽  
Larval Instar ◽  
Weight Ratio ◽  
Dry Weight ◽  
Chironomus Riparius ◽  
Consumption Rates ◽  
Rate Of Oxygen Consumption ◽  
Wet Weight

1. The oxygen consumption rates of 3rd- and 4th-instar larvae of Chironomus riparius have been measured at 10 and 20° C. using a constant-volume respirometer. 2. The oxygen consumption is approximately proportional to the 0.7 power of the dry weight: it is not proportional to the estimated surface area. 3. This relationship between oxygen consumption and dry weight is the same at 10 and at 20° C.. 4. The rate of oxygen consumption at 20° C. is greater than at 10° C. by a factor of 2.6. 5. During growth the percentage of dry matter of 4th-instar larvae increases from 10 to 16 and the specific gravity from 1.030 to 1.043. 6. The change in the dry weight/wet weight ratio during the 4 larval instar supports the theory of heterauxesis. 7. At 20° C., ‘summer’ larvae respire faster than ‘winter’ larvae.

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