Ageing studies on three species of freshwater mussels from a metal-polluted watershed in Nova Scotia, Canada

1992 ◽  
Vol 70 (7) ◽  
pp. 1284-1291 ◽  
Author(s):  
Janice L. Metcalfe-Smith ◽  
Roger H. Green
Keyword(s):  
Growth Rate ◽  
Nova Scotia ◽  
Shell Length ◽  
Metal Pollution ◽  
Freshwater Mussels ◽  
Population Parameters ◽  
Elliptio Complanata ◽  
Growth Bands ◽  
Mussel Shells ◽  
Age Estimates

Freshwater mussels are increasingly used to monitor metal pollution in freshwater systems. Mussels are long-lived, and age is a factor that may influence metal concentrations in their tissues. Species that can be precisely aged are most suitable for biomonitoring because they can be standardized for this factor. Precise age estimates are also needed for determining the effects of contamination on population parameters such as growth rate. Elliptio complanata, Anodonta implicata, and Alasmidonta undulata (family Unionidae) were collected from two Nova Scotia lakes contaminated with arsenic and mercury. Mussel shells were weighed, measured, and sectioned, and two independent counts of internal growth bands were made. External rings were also counted for A. implicata. Age estimates based on internal bands were most precise for E. complanata (r2 = 0.71 vs. 0.35 for A. implicata and 0.29 for A. undulata). Estimates based on external rings were more precise (r2 = 0.69) than those based on internal bands for A. implicata, but were believed to include disturbance rings. Shell length and weight were similarly correlated with age for a given species and population, but relationships were less clear in the lake with the more variable habitat. Elliptio complanata were much smaller at a given age in the more contaminated lake.

X-ray Fluorescence Analysis of Trace Metals in the Annual Growth Layers of Freshwater Mussel Shells

1989 ◽  
Vol 33 ◽  
pp. 665-670
Author(s):  
William E. Maddox ◽  
Leon Duobinis-Gray ◽  
David A. Owen ◽  
James B. Sickel
Keyword(s):  
Trace Metals ◽  
Metal Pollution ◽  
Freshwater Mussels ◽  
Freshwater Mussel ◽  
Fluorescence Analysis ◽  
Annual Growth ◽  
X Ray ◽  
Filter Feeders ◽  
Mussel Shells

Freshwater mussels (Mollusca: Unionidae) are filter feeders that are relatively immobile, widely distributed and are known to concentrate trace metals in their shells (1,2,3). These characteristics make them good candidates for monitoring metal pollution in lakes and rivers. Another characteristic of mussels that make them particularly attractive as pollution monitors is the fact the shell is deposited in distinctive, annual growth layers. The concentrations of metals in these shell layers may provide a history ol the metals present in the environment where the mussel was collected.

scholarly journals An insight into the structure, composition and hardness of a biological material: the shell of freshwater mussels

RSC Advances ◽  
2020 ◽  
Vol 10 (49) ◽  
pp. 29543-29554 ◽  
Author(s):  
Anupam Chakraborty ◽  
Saida Parveen ◽  
Dipak Kr. Chanda ◽  
Gautam Aditya
Keyword(s):  
Biological Material ◽  
Freshwater Mussels ◽  
Freshwater Mussel ◽  
Mussel Shells ◽  
Insight Into

Freshwater mussel shells: prospects as multifunctional biological material.

Genetics of growth rate variation in bivalves: aneuploidy and heterozygosity effects in a Crassostrea gigas family

Genome ◽  
1992 ◽  
Vol 35 (1) ◽  
pp. 39-45 ◽  
Author(s):  
C. Thiriot-Quiévreux ◽  
G. H. Pogson ◽  
E. Zouros
Keyword(s):  
Growth Rate ◽  
Shell Length ◽  
Chromosome Complement ◽  
Significant Negative Correlation ◽  
Rate Variation ◽  
Chromosome Loss ◽  
The Pacific ◽  
Marine Bivalves ◽  
Two Factors ◽  
Allozyme Loci

Enzyme homozygosity and somatic aneuploidy are both known to adversely affect juvenile growth rate in marine bivalves. We have examined the joint effects of these two factors by scoring genotypes at nine segregating allozyme loci and counting the numbers of chromosomes lost in 30 cells in each of 83 full sibs of the Pacific oyster. A highly significant negative correlation was observed between the number of chromosomes missing and shell length in full sibs of the same age. No relationship was seen, however, between allozyme heterozygosity and either shell length or chromosome loss, nor was there any difference in the distribution of aneuploidy among genotypes at any given enzyme locus. Thus, the effects of homozygosity and aneuploidy on growth rate appear to have different genetic bases. Even in the most aneuploid oysters, more than half the cells examined had a complete chromosome complement of 2n = 20. This eliminates somatic aneuploidy as an explanation for the excess of enzyme homozygosity frequently observed in populations of marine molluscs. Significant deviations from Mendelian expectations, favoring homozygotes at some loci and heterozygotes at others, were recorded at eight of the nine allozyme loci, but these occurred independently of the aneuploidy observed. Our results suggest that within families a much larger component of variation in growth rate is due to aneuploidy than to allozyme genotype, but this conclusion cannot, at present, be extended to natural populations.Key words: aneuploidy, heterozygosity, growth rate, oysters.

scholarly journals Demographic aspects of Chrysomya megacephala (Diptera, Calliphoridae) adults maintained under experimental conditions: reproductive rate estimates

2006 ◽  
Vol 49 (3) ◽  
pp. 457-461 ◽  
Author(s):  
Marcelo Henrique de Carvalho ◽  
Claudio José Von Zuben
Keyword(s):  
Growth Rate ◽  
Life Expectancy ◽  
Reproductive Rate ◽  
Demographic Parameters ◽  
Intrinsic Growth Rate ◽  
Experimental Conditions ◽  
Chrysomya Megacephala ◽  
Finite Growth ◽  
Life Expectancy Estimate ◽  
Age Estimates

The objective of this work was to evaluate some aspects of the populational ecology of Chrysomya megacephala, analyzing demographic aspects of adults kept under experimental conditions. Cages of C. megacephala adults were prepared with four different larval densities (100, 200, 400 and 800). For each cage, two tables were made: one with demographic parameters for the life expectancy estimate at the initial age (e0), and another with the reproductive rate and average reproduction age estimates. Populational parameters such as the intrinsic growth rate (r) and the finite growth rate (lambda) were calculated as well.

Age, growth and mortality of redfish Centroberyx affinis

2001 ◽  
Vol 52 (4) ◽  
pp. 637 ◽  
Author(s):  
A. K. Morison ◽  
K. R. Rowling
Keyword(s):  
Growth Rate ◽  
Significant Variation ◽  
Fork Length ◽  
Age And Growth ◽  
Average Error ◽  
Natural Mortality ◽  
Commercial Catch ◽  
Thin Sections ◽  
The Mean ◽  
Age Estimates

Age and growth of 5678 redfish, collected during 1991–98 from Australia’s South East Fishery, were estimated from thin sections of otoliths. A maximum age of 44 years was recorded for a 30 cm (fork length) female, but 80%of females in the commercial catch were <10 years, and 80%of males were <13 years. The largest was a 34 cm female estimated to be 36 years old. Repeated age estimates of a subsample revealed an average error of 3.79%. There was significant variation in the mean length-at-age among years, and there were significant effects for age*year, age*sex, age*region, region*year, and sex*region*year interactions. Assessments of the fishery have assumed a single stock, because tagging results from the 1980s indicate movement of redfish along the coast. This study found consistent differences in sex ratio and growth rate between regions, which indicate some structuring within the population. However, the differences in growth rates are not consistent among years and could not be explained by differences in depths fished, suggesting a more dynamic situation than spatially segregated stocks. Estimates of natural mortality ranged from 0.07 to 0.11 year–1 and differed between regions.

scholarly journals Recovering Population Parameters from a Single Gene Genealogy: An Unbiased Estimator of the Growth Rate

2010 ◽  
Vol 28 (5) ◽  
pp. 1617-1631 ◽  
Author(s):  
Yosef E. Maruvka ◽  
Nadav M. Shnerb ◽  
Yaneer Bar-Yam ◽  
John Wakeley
Keyword(s):  
Growth Rate ◽  
Unbiased Estimator ◽  
Single Gene ◽  
Population Parameters ◽  
Gene Genealogy

Commensalism Between an Epizoic Limpet, Patelloida nigrosulcata, and Its Gastropod Hosts, Haliotis roei and Patella laticostata, on Intertidal Platforms off Perth, Western Australia

1990 ◽  
Vol 41 (5) ◽  
pp. 647 ◽  
Author(s):  
RE Scheibling ◽  
T Evans ◽  
P Mulvay ◽  
T Lebel ◽  
D Williamson ◽  
...  
Keyword(s):  
Growth Rate ◽  
Interspecific Competition ◽  
Western Australia ◽  
Shell Length ◽  
Positive Relationship ◽  
Selective Force ◽  
Size Relationship ◽  
Strong Positive Relationship ◽  
Commensal Relationship

On intertidal limestone platforms off Perth and neighbouring islands, the limpet Patelloida nigrosulcata occurs only on the shells of living abalone (Haliotis roei) and other limpets (Patella laticostata). The incidence of commensalism varies among sites and between habitats within sites but is consistently high (> 80%) among dense abalone populations along the seaward margin of platforms. There is usually only 1 limpet per shell, although 2 or 3 limpets occasionally co-occur. A strong positive relationship in size (shell length) between Patelloida nigrosulcata and H. roei indicates that limpets settle on juvenile abalone and grow at a rate proportional to the growth rate of their host. A similar size relationship exists between Patelloida nigrosulcata and Patella laticostata. Patelloida nigrosulcata forages diurnally from a home scar and markedly limits the growth of erect macroalgae on the host shell. Escape from intense interspecific competition with other molluscan grazers on the platforms may have been a strong selective force in the evolution of this commensal relationship.

Annual Life Cycle and Production of the Chaetognath Sagitta elegans in Bedford Basin, Nova Scotia

1973 ◽  
Vol 30 (3) ◽  
pp. 333-344 ◽  
Author(s):  
D. D. Sameoto
Keyword(s):  
Growth Rate ◽  
Life Cycle ◽  
Nova Scotia ◽  
Turnover Rate ◽  
Degree Days ◽  
Annual Life Cycle ◽  
Order Of Magnitude ◽  
Annual Turnover

In Bedford Basin, Nova Scotia, Sagitta elegans has two main generations per year, one in the spring and one in the fall. The biomass of S. elegans per 100 m3 of water was an order of magnitude greater in the Basin than that reported previously for St. Margaret’s Bay, N.S. The growth rate and the number of degree days needed to mature were similar to those found for S. elegans in St. Margaret’s Bay. Annual turnover rate for S. elegans in the Basin was 5.6 and yearly production was estimated at 27.0 kcal per year or 9.0% of the yearly copepod production. It was calculated that the species used 90.4 kcal per m2 per year in respiration. The percentage of the total yearly production of copepods consumed by S. elegans was estimated at 36%.

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