Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-24T07:32:33.148Z Has data issue: false hasContentIssue false
  • English
  • Français

Differences in numbers and inequalities in mass and fecundity during the egg-producing period for Raphidascaris acus (Nematoda: Anisakidae)

Published online by Cambridge University Press:  06 April 2009

A. J. Szalai  and
T. A. Dick
A. J. Szalai
Affiliation:
Department of Zoology, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
T. A. Dick
Affiliation:
Department of Zoology, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
Get access Rights & Permissions [Opens in a new window]

Summary

Maturity, mass and sex were determined for individual Raphidascaris acus from northern pike, Esox lucius from Dauphin Lake, Manitoba. Length, width and total fecundity of female worms; seasonal changes in worm numbers, growth and maturity; and inequalities in mass and fecundity were quantified for 8 sample periods between April and September. Recruitment of R. acus is most rapid in early spring and continues throughout summer. An accumulation of larvae over winter leads to a peak in the number of gravid worms in spring, while increased feeding by post-spawning pike on yellow perch, Perca fluviatilis, leads to lower levels of gravid worms throughout summer and early autumn. Gravid worms found in spring versus summer were similar with respect to all measured variables and do not appear to be from genetically distinct populations. The strength of the correlation between fecundity and mass for worms was variable between pike and between sample periods, and only weakly correlated when the data were pooled. Much of this variation could be attributed to continued growth of gravid worms after maturation. Worms found in June were smaller, less fecund and less variable and inequalities in mass and fecundity measured using Gini coefficients (GCs) and Lorenz curves (LCs) were most similar at this time. For all other sample periods inequality in fecundity was greater than the corresponding value for mass. Similarity between GCs based on mass and fecundity was maximum when the coefficient of variation (C.V.) for mass was greater than the corresponding C.V. for fecundity. These observations suggest that one must be cautious when applying GCs and LCs to the analysis of parasite populations.

Keywords

Raphidascaris acusfecundityworm numbersmassseasonal variationsegg production
Type
Research Article
Information
Parasitology , Volume 98 , Issue 3 , June 1989 , pp. 489 - 495
Copyright
Copyright © Cambridge University Press 1989

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Bennet, S. & Bowers, D. (1976). An Introduction to Multivariate Statistics for Social and Behavioural Sciences. New York: John Wiley & Sons.Google Scholar
Blueweiss, L., Fox, H., Kudzma, V., Nakashima, D., Peters, R. & Sams, S. (1978). Relationships between body size and some life history parameters. Oecologia 37, 256–72.CrossRefGoogle ScholarPubMed
Dobson, A. P. (1986). Inequalities in the individual reproductive success of parasites. Parasitology 92, 675–82.CrossRefGoogle ScholarPubMed
Finn, J. P. (1970). The protective mechanisms in diseases of fish. Veterinary Bulletin 40, 873–86.Google Scholar
Margolis, L., Esch, G. W., Holmes, J. C., Kuris, A. M. & Schad, G. A. (1982). The use of ecological terms in parasitology. Journal of Parasitology 68, 131–3.CrossRefGoogle Scholar
Riggs, M. R., Lemly, A. D. & Esch, G. W. (1987). The growth, biomass and fecundity of Bothriocephalus acheilognathi in a North Carolina cooling reservoir. Journal of Parasitology 73, 893–900.CrossRefGoogle Scholar
Scheiner, S. M. (1987). Size and fecundity hierarchies in an herbaceous perennial. Oecologia 74, 128–32.CrossRefGoogle Scholar
Shostak, A. W. (1986). Sources of variability in life-history characteristics of the annual phase of Triaenophorus crassus (Cestoda: Pseudophyllidea). Ph.D. thesis, University of Manitoba, Winnipeg.Google Scholar
Shostak, A. W. & Dick, T. A. (1987). Individual variability in reproductive success of Triaenophorus crassus Forel (Cestoda: Pseudophyllidea), with comments on the use of the Lorenz curve and Gini coefficient. Canadian Journal of Zoology 65, 2878–85.CrossRefGoogle Scholar
Smith, C. C. & Fretwell, S. D. (1974). The optimal balance between size and number of offspring. The American Naturalist 108, 499–505.CrossRefGoogle Scholar
Smith, J. D. (1984). Taxonomy of Raphidascaris spp. (Nematoda: Anisakidae) of fishes, with a redescription of Raphidascaris acus (Bloch, 1772). Canadian Journal of Zoology 62, 685–94.CrossRefGoogle Scholar
Smith, J. D. (1986). Seasonal transmission of Raphidascaris acus (Nematoda), a parasite of freshwater fishes, in definitive and intermediate hosts. Environmental Biology of Fishes 16, 295–308.CrossRefGoogle Scholar
Weiner, J. & Solbrig, O. T. (1984). The meaning and measurement of size hierarchies in plant populations. Oecologia 61, 334–6.CrossRefGoogle ScholarPubMed
Wilson, J. B. & Levin, D. A. (1986). Some genetic consequences of skewed fecundity distributions in plants. Theoretical and Applied Genetics 73, 113–21.CrossRefGoogle ScholarPubMed