Population ecology of the freshwater mussel Anodonta grandis grandis in a Precambrian Shield lake

1990 ◽  
Vol 68 (9) ◽  
pp. 1931-1941 ◽  
Author(s):  
J. D. Huebner ◽  
D. F. Malley ◽  
K. Donkersloot
Keyword(s):  
Yellow Perch ◽  
Live Weight ◽  
Freshwater Mussel ◽  
Dry Weight ◽  
Fine Sand ◽  
Turnover Time ◽  
Experimental Lakes Area ◽  
Precambrian Shield ◽  
Sublittoral Zone ◽  
Anodonta Grandis

Anodonta grandis grandis is found in about half of 50 Experimental Lakes Area lakes surveyed but is abundant in only some of these lakes, including lake 377. Lake 377 is a typical small Precambrian Shield lake, 27.7 ha in area and 17.9 m in maximum depth, with [Ca2+] of [Formula: see text], conductivity of 25 μmho∙cm−1 (1 mho = 1 S), and alkalinity of [Formula: see text]. The water renewal time of approximately 187 days is shorter than that of most Precambrian Shield lakes. Bottom sediments in the sublittoral zone ranged from fine sand through granules to cobbles and boulders. Several species of possible glochidial host fish including yellow perch were collected from lake 377. The size of the mussel population, estimated by depth-stratified random sampling, was 36 800 ± 12 000 (± 95% confidence interval). Mean density was 0.133 mussels/m2 lake surface, and maximum density was 4.3 mussels/m2. Mussels were most abundant in the 1.5- to 3.1-m depth stratum. Mean lengths and weights in collections ranged from 77 to 87 mm and from 43 to 56 g, respectively. Maximum length and weight were 117.9 mm and 109.6 g, respectively. Based on external annuli, mussels live to 15+ years in lake 377. Flesh and shell averaged 25.1 and 23.2% of live weight, respectively. Calcium constituted 44.7% of the ash weight of shell. We estimated a standing dry weight biomass of mussels of 330–390 mg∙m−2 and dry weight production of 60 mg∙m−2∙year−1. This is [Formula: see text] of the estimated annual dry weight algal production. The shells of live mussels contain [Formula: see text] of the total calcium in lake 377. Despite oligotrophic conditions and low [Ca2+], lake 377 supports a substantial population of A. g. grandis growing at a moderate rate. Lake 377 may be a favourable habitat for this species because of its short water-turnover time.

scholarly journals Quality of rubber tree rootstock seedlings grown in protected environments and alternative substrates

2020 ◽  
Vol 42 ◽  
pp. e43469
Author(s):  
Abimael Gomes da Silva ◽  
Edilson Costa ◽  
Talita Cristina Campos Pereira ◽  
Flávio Ferreira da Silva Binotti ◽  
Erivaldo José Scaloppi Junior ◽  
...  
Keyword(s):  
Experimental Design ◽  
Rubber Tree ◽  
Dry Weight ◽  
Fine Sand ◽  
Tree Seedlings ◽  
Quality Indices ◽  
High Quality ◽  
Plant Nursery ◽  
Randomized Experimental Design

This study aimed to evaluate the quality of Hevea brasiliensis seedlings, a GT1 clone, produced in protected environments in a variety of substrates. The treatments consisted of 13 substrates composed of combinations of cattle manure, soil from a ravine, medium vermiculite, superfine vermiculite and washed fine sand and two environments: a greenhouse with 50% shade using aluminized screen and a plant nursery with 50% shade using a Sombrite® screen. There were no replications of the environments; therefore, each one was considered an experiment. For each environment, a completely randomized experimental design with five replications was used to evaluate the substrates. Subsequently, the average squares of the residuals of individual variance analyses of these treatments (substrates) were evaluated, and because they did not exceed an approximate ratio of 7:1, a combined analysis of experiments was performed with Sisvar software. Two hundred eighty days after sowing, the dry weight, plant height, stem diameter, diameter at five centimeters above soil and the seedling quality indices were evaluated. Results indicated that substrates with a low amount of manure and sand and a high amount of vermiculite (S9 and S13) produced rubber tree seedlings of high-quality. The environment with greater radiation availability was better for the development of high-quality rubber tree seedlings.

scholarly journals Maternal effects as a recruitment mechanism in Lake Michigan yellow perch (Perca flavescens)

2001 ◽  
Vol 58 (7) ◽  
pp. 1477-1487 ◽  
Author(s):  
Christopher J Heyer ◽  
Thomas J Miller ◽  
Fred P Binkowski ◽  
Elaine M Caldarone ◽  
James A Rice
Keyword(s):  
Maternal Effects ◽  
Null Hypothesis ◽  
Yellow Perch ◽  
Lake Michigan ◽  
Gonadosomatic Index ◽  
Perca Flavescens ◽  
Dry Weight ◽  
Phenotypic Traits ◽  
High Fecundity ◽  
Larval Traits

Changes that occurred in the distribution of adult Lake Michigan yellow perch (Perca flavescens) phenotypic traits suggest that maternal effects on larval traits may be substantially influencing the recruitment of this heavily exploited species. We investigated maternal effects on yellow perch larvae at hatching in 10 maternal lines to test the null hypothesis of no effect of maternal phenotype on offspring phenotype and condition. Analyses lead to a rejection of the null hypothesis and indicated that the observed maternal effects likely resulted from differences among females in size, age, gonadosomatic index, and egg production. The observed maternal effects were expressed in the offspring by differences in larval total length, yolk volume, dry weight, and DNA quantity. Older, larger females were found to have high fecundity, yet low gonadosomatic index. Furthermore, older, larger females produced offspring that were, on average, short with large yolk sacs and high quantities of body reserves, as measured by dry weight and total DNA content. We conclude that the distribution of Lake Michigan yellow perch larval traits at hatching is linked to maternal influences and that this linkage may provide a mechanism through which managers can help rebuild the population.

The Macrobenthic Infauna of the Offshore Northern North Sea

1989 ◽  
Vol 69 (1) ◽  
pp. 123-143 ◽  
Author(s):  
A. Eleftheriou ◽  
D.J. Basford
Keyword(s):  
North Sea ◽  
Dry Weight ◽  
Fine Sand ◽  
Surface Deposit ◽  
Number Of Species ◽  
The North ◽  
Deposit Feeders ◽  
The North Sea ◽  
Northern North Sea ◽  
Deposit Feeding

Between 1980 and 1985 ninety-seven stations were sampled by Smith-Mclntyre grab from the offshore northern section of the North Sea. Four hundred and nine infaunal species were identified from the 76 selected macrofaunal stations. The number of species per station varied from 25 to 80 with a maximum abundance of 9,600 individuals m−2. The biomass ranged from 0.13 to 18.86 g dry weight m−2. At most stations, however, biomass varied between 1 and 4 g dry weight m−2. Diversity and abundance were highest in the 120–140 m zone, characterised by fine sand containing variable amounts of silt. The highest biomasses were recorded in two areas; firstly where stronger currents predominate and the sediments are coarser (east of Shetland and west of the Norwegian Trough), and secondly in the fine sandy deposits of the centrally located area. In the silty sediments (Fladen Ground and smaller depressions) there was a predominantly subsurface deposit-feeding community, whereas in the coarser area east of the Shetlands carnivores predominated. Over the remaining area surface deposit feeders were dominant.

Behaviour, Energetics, and Associated Mortality of Young-of-the-Year White Perch (Morone americana) and Yellow Perch (Perca flavescens) under Simulated Winter Conditions

1991 ◽  
Vol 48 (4) ◽  
pp. 672-680 ◽  
Author(s):  
Timothy B. Johnson ◽  
David O. Evans
Keyword(s):  
Yellow Perch ◽  
White Perch ◽  
Perca Flavescens ◽  
Direct Consequence ◽  
Dry Weight ◽  
Routine Metabolic Rate ◽  
Winter Period ◽  
Small Fish ◽  
Morone Americana ◽  
Winter Conditions

After 150 d of simulated winter conditions, 71.2% of the white perch (Morone americana) had died at 2.5 °C, while only 11.1% had died at 4.0 °C. For yellow perch (Perca flavescens), 0.8% had died at 2.5 °C, while 17.7% had died at 4.0 °C. For both species, small fish died first. Multiple regression models relating overwinter mortality versus fall total length and winter duration predict 3.3 times greater mortality for white perch versus similar sized yellow perch at winter temperature regimes typical of the Great Lakes region. In laboratory tanks, white perch remained active throughout the winter period, while yellow perch sought cover and rested on or near the bottom of the experimental tanks. As a direct consequence, yellow perch had a lower routine metabolic rate and consumed body energy more gradually than white perch. During their inactive wintering period at 4.0 °C, yellow perch consumed 25.8% less oxygen than white perch. Actual measurements of dry weight loss indicated that yellow perch in the experimental tanks at 2.5 °C consumed 24.6% less dry weight than similar sized white perch. These differences in overwinter behaviour, metabolism, and survival appear to be adequate to account for observed differences in survival of these species in the wild.

Seasonal Field Analyses of Fat Content, Live Weight, Dry Weight and Water Content of the Aphidophagous Scymnodes Lividigaster (Mulsant) and Mycophagous Leptothea Galbula (Mulsant) (Coleoptera: Coccinellidae).

1981 ◽  
Vol 29 (5) ◽  
pp. 679 ◽  
Author(s):  
JME Anderson
Keyword(s):  
Quantitative Analysis ◽  
Survival Rate ◽  
Water Content ◽  
Seasonal Changes ◽  
Prey Species ◽  
Live Weight ◽  
Dry Weight ◽  
Subjective Assessment ◽  
Fat Content ◽  
Fat Reserves

Over 36 and 24 months, respectively, both the aphidophagous Scymnodes lividigaster (Muls.) and the mycophagous Leptothea galbula (Muls.) accumulated fat before periods of dormancy, but contained little fat after dormancy and during breeding. Over the whole period, there were no significant differences between sexes or between years in either species, except that dormant females contained significantly more fat than males, and that during breeding males of S. lividigaster contained significantly more fat than females. Subjective assessment of fat reserves gave the same results as did quantitative analysis. Live and dry weights of females were higher during breeding and dormancy than after dormancy; live weights of females were higher than those of males. Water content was lower during dormancy than during breeding. In L. galbula, seasonal changes were similar in a dry and a well watered habitat; any differences appeared related to a higher survival rate in females compared with males, especially in the poorer habitat. In S. lividigaster, seasonal changes in fat content were negatively related to changes in abundance of an essential prey species.

Pasture type in relation to live-weight gain, carcass composition, iodine nutrition and some rumen characteristics of sheep III. Effects of treatment with iodine

1963 ◽  
Vol 61 (2) ◽  
pp. 197-200 ◽  
Author(s):  
D. S. Flux ◽  
G. W. Butler ◽  
A. C. Glenday
Keyword(s):  
White Clover ◽  
Live Weight ◽  
Dry Weight ◽  
Carcass Composition ◽  
Iodine Nutrition ◽  
Rye Grass ◽  
Short Rotation ◽  
Thyroid Glands ◽  
Iodine Treatment ◽  
The Mean

1. The mean thyroid weights of ewes grazed on the different pastures (perennial rye-grass (P), perennial rye-grass plus white clover (P + C), short-rotation rye-grass (S), short-rotation rye-grass plus white clover (S + C)) did not differ significantly, but those injected with iodinated poppy-seed oil had lighter (P < 0·01) thyroids than the non-injected ewes grazed on the same pastures.2. Neither the live weights of the ewes nor their lambing performances were affected significantly by treatment with iodine.3. Lambs from ewes grazed on pastures containing white clover had thyroid glands significantly heavier than those of ewes grazed on rye-grass pastures. The largest thyroids were from the lambs of ewes not treated with iodine and grazed on S.4. The iodine contents of the thyroids of the lambs at slaughter, measured as percentage dry weight, did not differ significantly. It seems likely that the differences in thyroid weights were caused by factors operating early in the lives of the lambs.5. The lambs of ewes injected with iodine grew faster after weaning than those of non-injected ewes on the same pastures. The interpretation that this difference was in fact caused by the iodine treatment of the ewes was not wholly acceptable, because the differences in growth rate were not greatest in those groups of lambs showing greatest differences in thyroid weight.

Growth Rates and Nitrogen and Carbohydrate Contents of Juvenile Clams, Saxidomus giganteus, Fed Three Species of Algae

1973 ◽  
Vol 30 (12) ◽  
pp. 1825-1830 ◽  
Author(s):  
P. R. Walne
Keyword(s):  
Isochrysis Galbana ◽  
Live Weight ◽  
Dry Weight ◽  
Maximum Growth ◽  
Condition Index ◽  
Maximum Growth Rate ◽  
Experimental Conditions ◽  
Total Dry Weight ◽  
Tetraselmis Chui ◽  
Saxidomus Giganteus

Estimates were made of the increase in live and dry weights and in the content of ash, organic matter, carbohydrate (as glucose), and nitrogen when juveniles of the clam Saxidomus giganteus were fed for 21 days at various concentrations of Tetraselmis chui, Isochrysis galbana, and Phaeodactylum tricornutum. The condition index (organic weight as a percent of total dry weight) increased in all the experimental conditions with a mixture of I. galbana and T. chui, yielding a significantly higher index than either species on its own. The relative gain in glucose was greater than the increase in live weight or in nitrogen. The increase in live weight was such that the nigrogen content was approximately constant at 6–7 μgN/mg live weight irrespective of the feeding conditions. The N:glucose ratio decreased with increasing concentrations of I. galbana and P. tricornutum, and at the higher concentrations, where the maximum growth rate of clams occurred, the ratios were lower than in any of the clams fed on T. chui.

ECONOMIC INJURY LEVELS OF THE ALFALFA WEEVIL (COLEOPTERA: CURCULIONIDAE)

1973 ◽  
Vol 105 (1) ◽  
pp. 61-74 ◽  
Author(s):  
Philip G. Koehler ◽  
David Pimentel
Keyword(s):  
Food Consumption ◽  
Larval Density ◽  
New York State ◽  
Live Weight ◽  
Dry Weight ◽  
Larval Feeding ◽  
Larval Food ◽  
Alfalfa Weevil ◽  
Second Growth ◽  
Economic Injury

AbstractEconomic injury levels of the alfalfa weevil on alfalfa were investigated in New York State. The dry weight food consumption for the larval stage of the alfalfa weevil averaged 7.34 mg/larva. For every gram (dry weight) of alfalfa consumed, 1.59 g (live weight) in insect tissue was produced. In the laboratory, it was found that insect food consumption could account for only about 50% of the total weight loss in alfalfa plants after 10 days of larval feeding. Therefore, alfalfa weevil damage to alfalfa was more than the larval food consumption, and this was believed to be due to the loss of the plant’s photosynthetic potential. In the field on first growth alfalfa, the economic injury level was calculated to be 56 larvae/stem. First growth alfalfa was less severely injured by alfalfa weevil larvae than our second growth alfalfa infested with equal populations of alfalfa weevils. It was shown that first growth alfalfa was able to compensate for 87% of the insect feeding while second growth alfalfa could compensate for only 50%. Since the alfalfa plant’s capacity to compensate for alfalfa weevil feeding can vary due to environmental conditions and plant characteristics, economic injury levels must be adjustable. To provide more reliability to economic injury levels, we propose that in alfalfa the following seven measurements be made: (1) alfalfa weevil larval density; (2 and 3) parasites and predators of the weevil; (4) rainfall and moisture level; (5) plant nutrients; (6) alfalfa variety; and (7) stage and previous management of alfalfa stand.

Seasonal prevalence, intensity of infestation, and distribution of glochidia of Anodonta grandis simpsoniana Lea on yellow perch, Perca flavescens

1991 ◽  
Vol 69 (4) ◽  
pp. 964-972 ◽  
Author(s):  
Wolfgang A. Jansen
Keyword(s):  
Body Weight ◽  
Fish Species ◽  
Yellow Perch ◽  
Perca Flavescens ◽  
Relative Importance ◽  
Seasonal Prevalence ◽  
Attachment Sites ◽  
Anodonta Grandis ◽  
External Body

Five fish species were sampled at regular intervals in Narrow Lake, central Alberta, and examined for the prevalence and intensity of infestation by glochidia larvae of Anodonta grandis simpsoniana. Yellow perch (Perca flavescens) collected between January and May were infested with glochidia, whereas perch captured between June and October were free of larvae. The prevalence of infestation increased gradually from 86 to 95% between January and May, and the intensity of infestation increased from 5.7 to 49.4 glochidia per fish over the same period. Glochidia were found on most external body surfaces, including the gills. Glochidia attached preferentially to some anatomical areas, especially pectoral and pelvic fins. Furthermore, the relative importance of certain attachment sites differed significantly among sampling dates. Neither sex, size (length or weight), or age of perch significantly affected the intensity of infestation per fish. However, small (4.4–6.0 cm), 1- and 2-year-old fish carried more than 12 times the number of glochidia per gram of body weight than large (12.1–15.7 cm), 4- to 7-year-old fish. Both perch behavior and distribution and clam reproduction and distribution provide possible explanations for the observed patterns in the prevalence and intensity of infestation and in the distribution of the glochidia on the host.

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