The biology and energetics of Eogammarus confervicolus (Stimpson) (Amphipoda, Anisogammaridae) at the Squamish River Estuary, B.C.

1980 ◽  
Vol 58 (9) ◽  
pp. 1652-1663 ◽  
Author(s):  
C. D. Levings
Keyword(s):  
River Estuary ◽  
Dry Weight ◽  
Growth Efficiency ◽  
Gammarid Amphipod ◽  
Fucus Distichus ◽  
Consumption Rates ◽  
Enteromorpha Linza ◽  
Eogammarus Confervicolus ◽  
Cover Material ◽  
Pilayella Littoralis

Data on the biology and energetics of the gammarid amphipod Eogammarus confervicolus (Stimpson) are presented from the Squamish River estuary in southwestern British Columbia. At low tide, E. confervicolus was most abundant under cover material, especially sedge rhizomes (Carex lyngbyei) and rockweed (Fucus distichus). Maximum biomass was observed in spring under the sedge mat (16.1 g dry weight m−2) and rockweed (16.8 g dry weight m−2). The minimum sized female bearing eggs was observed to be approximately 7 mm and egg number ranged up to 75. Incubation time (10 °C, 15‰) was 17 days. In 2 years of data, mature females were most abundant in samples from October to December and July to August. Oxygen consumption rates at 5 and 10 °C were lowest in fresh water and increased with higher salinities. At 15 °C, lower salinities increased consumption rates. Net growth efficiency (K2) was calculated from growth rates on four diets used in a previous study and for respiration under prevailing environmental conditions. The following are ranked diets: Enteromorpha linza (51.2%), Pilayella littoralis (44.2%), Navicula spp. (42.7%), and Carex lyngbyei debris (22.4%). The central sector of the estuary showed the highest K2 values when averaged over diets (53.2%).

Association and Feeding Relationships Between Eogammarus confervicolus (Amphipoda, Gammaridae) and Benthic Algae on Sturgeon and Roberts Banks, Fraser River Estuary

1980 ◽  
Vol 37 (1) ◽  
pp. 1-10 ◽  
Author(s):  
W. M. Pomeroy ◽  
C. D. Levings
Keyword(s):  
Vascular Plant ◽  
River Estuary ◽  
Algal Growth ◽  
Benthic Algae ◽  
Fraser River ◽  
Plant Debris ◽  
Engineering Structures ◽  
Gammarid Amphipod ◽  
Enteromorpha Linza ◽  
Eogammarus Confervicolus

Field and laboratory studies of the feeding and association of the gammarid amphipod Eogammarus confervicolus with algae and vascular plant debris were conducted on jetties, marshes, and sandflats at the Fraser River Estuary. Associations with Prasiola meridionalis (alga), and debris from Carex lyngbyei (vascular plant) were statistically significant. Vascular plant debris was more widespread in winter (January) compared to a summer survey (August). Laboratory growth rates and survival varied with food types, which were ranked (best to worst) as follows: Enteromorpha linza, Pylaiella littoralis, Porphyra spp., Navicula grevillei, Carex lyngbyei debris and Ulva lactuca. Assimilation efficiencies, measured with gravimetric and radioisotope techniques (14C) ranged from about 78% with P. littoralis to 62% with U. lactuca. Construction of jetties could increase the surface area for algal growth, but there would be no appreciable enhancement of primary production compared to a natural marsh/sandflat ecosystem.Key words: Crustacea, Eogammarus confervicolus, benthic algae, Fraser Estuary, intertidal distribution, feeding, ecological associations, engineering structures

Cereal Consumption, Production, and Prices in West Pakistan (Notes & Comments)

1968 ◽  
Vol 8 (2) ◽  
pp. 288-306 ◽  
Author(s):  
G. C. Hufbauer
Keyword(s):  
Food Consumption ◽  
Ad Hoc ◽  
Dry Weight ◽  
Small Sample ◽  
Tax Rates ◽  
Active Population ◽  
Early Settlement ◽  
Consumption Rates ◽  
Late Nineteenth ◽  
Better Than

In the late nineteenth and early twentieth centuries, several Punjab Settlement Officers attempted to estimate food consumption rates. These estimates, based on direct observation and ad hoc guesses, were made partly out of academic curiosity, but more urgently, as an aid in establishing the land revenue (i.e., tax) rates. The pre-1926 estimates are summarized in Table I, expressed in pounds of wheat and other foodgrain consumption per person per year1. Broadly speaking, the later, more systemtic observers (e.g., Sir Ganga Ram and C. B. Barry), found lower consumption levels than the earlier observers. It was generally accepted that the rural populace ate better than urban dwellers. Despite the ingenuity of the early Settlement Officers, their compiled estimates suffer from all the difficulties of haphazard small sample observation. Given the revenue purpose of the estimates, they may be biased towards the able-bodied, economically active, population. Further, the very early estimates may have confused dry weight with cooked weight, including water.

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.

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.

scholarly journals Initial Analysis of Plastic Debris Accumulation in the Estuary of Wonorejo River, Surabaya, Indonesia

2020 ◽  
Vol 148 ◽  
pp. 07001
Author(s):  
Setyo Budi Kurniawan ◽  
Muhammad Fauzul Imron
Keyword(s):  
River Estuary ◽  
Dry Weight ◽  
Sampling Point ◽  
Plastic Pollution ◽  
Plastic Debris ◽  
Debris Accumulation ◽  
Plastic Bags ◽  
Sampling Points ◽  
Advance Research ◽  
One Way Anova

The purpose of this research was to investigate the accumulation of plastic debris in the Wonorejo River Estuary, Surabaya, Indonesia. Visible plastic debris were collected from three (3) sampling points along the intertidal area of Wonorejo River Estuary. The correlation between sampling points (SPs) and the amount of the collected plastic debris (CPD) was analysed using one-way ANOVA. Result of one-way ANOVA showed that the sampling point was significantly affect the amount of the collected plastic debris (p<0.05). A further analysis using Tukey’s Significance Honest Test indicating a significantly higher CPD on SP2 compared to the SP1 and SP3 (p<0.05). The amount of CPD were 126.07±12.00 g dry weight/m2 from SP1, 375.97±16.72 g dry weight/m2 from SP2, and 291.13±36.28 g dry weight/m2 from SP3. The highest percentage of collected debris item was plastic bags (up to 57.90%), followed by bottle caps (up to 16.65%). The most identified plastic types were Low-Density Polyethylene (LDPE) (up to 73.13%), followed by Polypropylene (PP) (up to 17.22%). Understanding the accumulation of plastic debris in estuary is a fundamental requirement to conduct an advance research related to the marine plastic pollution and to determine further actions to solve this problem.

scholarly journals Toxic elements in free-living freshwater fish, water and sediments in Poland

2014 ◽  
Vol 58 (4) ◽  
pp. 589-595 ◽  
Author(s):  
Józef Szkoda ◽  
Jan Żmudzki ◽  
Agnieszka Nawrocka ◽  
Mirosława Kmiecik
Keyword(s):  
River Sediments ◽  
River Estuary ◽  
Absorption Spectrometry ◽  
Dry Weight ◽  
Fish Muscle ◽  
Average Concentration ◽  
Predatory Fish ◽  
Quality Assurance Programme ◽  
Lead And Cadmium ◽  
Vistula River

Abstract Samples for analysis were collected from 10 areas, including the major Polish rivers and lakes, with different sources of environmental pollution (industrial, municipal, and farming). The materials was taken from the lakes of Mazury, located in a non-industrialised region, from the Brda River, an area impacted by pig farms, from the lakes of Lipczyno Wielkie/Pomerania, from the Wkra River, an area impacted by poultry farms, from the Dunajec River at the Roznowski Reservoir, from the Vistula River at Cracow and Warsaw, from the Odra River at Wroclaw and the Warta River estuary, and also from Rybnik Power Station Reservoir. Concentrations of Pb, Cd, Hg, and As were analysed in 397 fish muscle and 128 sediment samples using an atomic absorption spectrometry technique. The analytical procedures were covered by a quality assurance programme. It was demonstrated that the average concentrations of lead, cadmium, and arsenic in fish were in the low hundredths and thousandths of a mg/kg and never exceeded permitted limits established for food. Higher values of these elements were found in fish from bodies of water located in the zone of influence of large urban agglomerations, especially the Cracow region. High concentrations of lead and cadmium were also found in Vistula River sediments near Cracow, where the maximum values were 134.10 mg/kg and 21.24 mg/kg dry weight for lead and cadmium respectively. The average concentration of mercury in a predatory fish muscle (0.179 mg/kg) was almost twice as high as in the omnivorous fish (0.103 mg/kg). Only a single fish sample exceeded the maximum limit for this metal (0.50 mg/kg) and did not present a risk to consumers’ health.

Particle-Size-Conversion Efficiency and Contaminant Concentrations in Lake Ontario Biota

1983 ◽  
Vol 40 (3) ◽  
pp. 328-336 ◽  
Author(s):  
Uwe Borgmann ◽  
D. M. Whittle
Keyword(s):  
Particle Size ◽  
Body Size ◽  
Conversion Efficiency ◽  
Food Chain ◽  
Lake Ontario ◽  
Dry Weight ◽  
Growth Efficiency ◽  
Fish Production ◽  
The Relationship ◽  
Zooplankton Production

The particle-size-conversion efficiency (log food consumption/production divided by log predator prey size ratio) is shown to be directly related to the relationship between the concentration of persistent contaminants accumulated primarily through the food chain and body size for organisms in pelagic ecosystems. The difference between particle-size-conversion efficiency for biomass and that for the contaminant gives the slope of the relationship between log contaminant concentration and log body size. This provides a useful theoretical framework for analyzing contaminant concentrations in aquatic biota without the need for specifying trophic level but still incorporating the idea of food chain accumulation. Concentrations of PCB, DDT, and mercury were examined in aquatic organisms from Lake Ontario, ranging in size from zooplankton to large salmonids (a 108 -fold range in dry weight). The slope of the double log plot of concentration versus weight varied from 0.20 to 0.22 for PCB and DDT and was approximately equal to 0.13 for mercury. This indicates that mercury is accumulated less efficiently through the food chain than PCB or DDT. After correcting for incomplete uptake and retention of the contaminant, an estimate of particle-size-conversion efficiency for biomass of about 0.26 was obtained, which agrees reasonably well with previous estimates obtained from growth efficiency experiments and analysis of particle-size spectra. These calculations indicate that potential fish production in Lake Ontario is ~ 120-fold lower than zooplankton production (for fish averaging 108-fold larger in body size as compared to zooplankton).Key words: particle-size-conversion efficiency, PCB, DDT, mercury, zooplankton production, fish production

Evaluation of a Method for Estimating Food Consumption Rates of Fish

1973 ◽  
Vol 30 (5) ◽  
pp. 623-629 ◽  
Author(s):  
Robert F. Carline ◽  
James D. Hall
Keyword(s):  
Food Consumption ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Growth Efficiency ◽  
Behavior Patterns ◽  
Growth Data ◽  
Wide Range ◽  
Consumption Rates ◽  
Similar Growth ◽  
Experimental Stream

A method of estimating food consumption rates of fish in nature from laboratory growth data was evaluated using juvenile coho salmon (Oncorhynchus kisutch) in three similar experiments. One group of coho was held individually in aquariums where movement was restricted. Another group was maintained in an experimental stream where the coho displayed many of their typical behavior patterns. All fish were fed known rations and both groups had similar growth efficiencies over a wide range of rations. Coho feeding at intermediate rates had the highest gross efficiencies. Aggressive activity did not affect growth efficiency. Results suggested that laboratory food and growth data may provide reasonably accurate estimates of food consumption of coho salmon in nature.

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.

scholarly journals Using energy budget data to assess the most damaging life-stage of an agricultural pest Mocis latipes (Guenèe, 1982) (Lepidoptera - Noctuidae)

2010 ◽  
Vol 70 (3) ◽  
pp. 459-463 ◽  
Author(s):  
MJT. Assunção-Albuquerque ◽  
MC. Peso-Aguiar ◽  
FS. Albuquerque
Keyword(s):  
Larval Development ◽  
Energy Budget ◽  
Plant Biomass ◽  
Life Stage ◽  
Larval Growth ◽  
Dry Weight ◽  
Growth Efficiency ◽  
Economic Damage ◽  
Gross Growth Efficiency ◽  
Mocis Latipes

There is much evidence to support that Mocis latipes larvae (Guenèe, 1852) are the most dangerous pasture pest and usually cause large environmental losses. However, no studies have been carried out to identify the instars during which this moth causes the most damage to the environment. Here we calculate M. latipes larval energy budget to assess its consumption across all instars and estimate the consumption/amount of plant biomass required to complete its larval development. Assimilation, respiration, consumption, excretion, gross growth efficiency and net growth efficiency were calculated. Pearson correlations were used to identify the best predictors that influenced larval growth and weight. Across all instars consumption increased exponentially, especially during the last phase. M. latipes larvae consumed ca 13.8% of total food from the first to the fifth instar, whereas during the sixth instars these larvae consumed ca 72.6%. Results also show that the best gross growth and net growth efficiency were obtained when larvae reached the fifth instar. The results also show that one larva of Mocis latipes consumes 1.02 g (dry weight) of Paspalum maritimum (Trin) in 19 days. Overall, our results indentified the sixth instar as the most destructive instar of this insect. Thus, once we know the most destructive instars of this pest, measures can be taken to disable M. latipes larval development and consequently stop their increase in plant consumption, reducing ecological and economic damage. This knowledge may eventually lead to reduced agricultural damage and contribute to sustainable farming strategies.

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