Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-27T20:42:12.183Z Has data issue: false hasContentIssue false
  • English
  • Français

The population age structure and reproductive biology of Gyrodactylus salaris Malmberg (Monogenea)

Published online by Cambridge University Press:  06 April 2009

P. D. Harris ,
P. A. Jansen  and
T. A. Bakke
P. D. Harris
Affiliation:
Department of Adult Education, University of Nottingham, Nottingham NG7 2RD
P. A. Jansen
Affiliation:
Zoological Museum, University of Oslo, Sars gt. 1, N-0562 Oslo 5, Norway
T. A. Bakke
Affiliation:
Zoological Museum, University of Oslo, Sars gt. 1, N-0562 Oslo 5, Norway
Get access Rights & Permissions [Opens in a new window]

Summary

Gyrodactylus salaris has recently become a major pathogen of Atlantic Salmon (Salmo salar) in Norway. The survivorship, population age structure and pattern of insemination of G. salaris were studied to determine the extent to which this species reproduces sexually. The age-specific mortality schedule of G. salaris could be described by an exponential model but day to day variations were large, with an increase in mortality after each birth. Modelling population growth using the best fit mortality schedule indicated that, at stable age structure, 35% of the population would consist of newborn and pre-1st birth flukes. Using testis, penis and embryo development, pre-1st birth and immediately post-1st birth flukes could be unambiguously identified, and established infections were found to contain 35% pre-1st birth flukes, as predicted. The proportion of pre-1st birth flukes in newly established infections was significantly smaller, probably because of differences in the rate of transmission between newborn and older flukes. Gyrodactylus salaris is relatively long-lived, and more than 40% of the population may survive to give birth for the third time. As gyrodactylids are protogynous, and the first daughter is probably produced asexually, this long-lived strategy ensures that a large part of the G. salaris population possesses a functional male system, and that the asexually derived flukes are a smaller component of the total population in this species. Flukes with whorls of inseminated spermatozoa within the seminal receptacle were found in all age groups possessing a functional male system, and were interpreted as having been cross-inseminated. G. salaris on susceptible Norwegian salmon appears to regularly reproduce sexually, possibly accounting for its morphological variability and wide range of potential salmonid hosts.

Keywords

Gyrodactylus salarisage-specific mortalitysexual reproduction
Type
Research Article
Information
Parasitology , Volume 108 , Issue 2 , February 1994 , pp. 167 - 173
Copyright
Copyright © Cambridge University Press 1994

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

Anderson, R. M. & Whitfield, P. J. (1975). Survival characteristics of the free-living cercarial population of the ectoparasitic digenean Transversotrema patialense. Parasitology 70, 295–310.Google Scholar
Bakke, T. A., Jansen, P. A. & Hansen, L. P. (1990). Differences in the host resistance of Atlantic salmon (Salmo salar) stocks to the monogenean Gyrodactylus Solaris Malmberg, 1957. Journal of Fish Biology 37, 577–87.CrossRefGoogle Scholar
Bakke, T. A., Jansen, P. A. & Kennedy, C. R. (1991). The host specificity of Gyrodactylus salaris Malmberg (Platyhelminthes, Monogenea): The susceptibility of Oncorhynchus mykiss (Walbaum) under experimental conditions. Journal of Fish Biology 39, 45–57.CrossRefGoogle Scholar
Bakke, T. A., Harris, P. D., Hansen, P. A. & Hansen, L. P. (1992 a). Host specificity and dispersal strategy in gyrodactylid monogeneans with particular reference to Gyrodactylus salaris (Platyhelminthes, Monogenea). Diseases of Aquatic Organisms 13, 45–57.CrossRefGoogle Scholar
Bakke, T. A., Harris, P. D. & Jansen, P. A. (1992 b). The susceptibility of Salvelinus fontinalis (Mitchill) to Gyrodactylus salaris Malmberg (Platyhelminthes; Monogenea) under experimental conditions. Journal of Fish Biology 41, 499–507.CrossRefGoogle Scholar
Bakke, T. A. & Mackenzie, K. (1993). Comparative susceptibility of native Scottish and Norwegian stocks of Atlantic salmon Salmo salar L., to Gyrodactylus salaris Malmberg: Laboratory experiments. Fishery Research 17, 69–85.CrossRefGoogle Scholar
Braun, E. (1966). Beiträge zur mikroskopischen Anatomic und Fortpflanzungsbiologie von Gyrodactylus wageneri von Nordmann, 1832. Zeitschrift für Parasitenkunde 28, 142–74.CrossRefGoogle Scholar
Deevey, E. (1947). Life tables for natural populations of animals. Quarterly Reviews of Biology 22, 283–314.Google Scholar
Halvorsen, O. & Hartvigsen, R. (1989). A review of the biogeography and epidemiology of Gyrodactylus salaris. NINA utredning 2, 1–41.Google Scholar
Harris, P. D. (1980). The behaviour of Gyrodactylus on living fishes. Proceedings of the 3rd European Multicolloquium of Parasitology,Cambridge 1980, p. 97.Google Scholar
Harris, P. D. (1985). Observations on the development of the male reproductive system in Gyrodactylus gasterostei Glaser, 1974. Parasitology 91, 519–29.Google Scholar
Harris, P. D. (1986). Species of Gyrodactylus from poeciliid fishes with a description of Gyrodactylus turnbulli sp. nov. from the guppy Poecilia reticulata Peters. Journal of Natural History 20, 183–91.CrossRefGoogle Scholar
Harris, P. D. (1989). Interactions between population growth and sexual reproduction in the viviparous monogenean Gyrodactylus turnbulli Harris, 1986 from the guppy Poecilia reticulata Peters. Parasitology 98, 245–51.CrossRefGoogle Scholar
Harris, P. D. (1993). Interactions between reproduction and population biology in gyrodactylid monogeneans – a review. Bulletin Français de la Pêche et de la Pisciculture 328, 47–65.CrossRefGoogle Scholar
Jansen, P. A. & Bakke, T. A. (1991). Temperature dependent reproduction and survival of Gyrodactylus salaris Malmberg, 1957 (Platyhelminthes: Monogenea) on Atlantic salmon (Salmo salar L.). Parasitology 102, 105–12.CrossRefGoogle ScholarPubMed
Jansen, P. A. & Bakke, T. A. (1993 a). Regulatory processes in the monogenean Gyrodactylus salaris-Atlantic salmon (Salmo salar L.) association. 1. Field studies in southeastern Norway. Fishery Research 17, 87–101.Google Scholar
Jansen, P. A. & Bakke, T. A. (1993 b). Regulatory processes in the monogenean Gyrodactylus salaris-Atlantic salmon (Salmo salar L.) association. 2. Experimental studies. Fishery Research 17, 103–14.Google Scholar
Johnsen, B. O. & Jensen, A. J. (1991). The Gyrodactylus story in Norway. Aquaculture 98, 289–302.CrossRefGoogle Scholar
Jones, M. K. & Whittington, I. D. (1992). Nuclear bodies in the egg cells of a Gyrodactylus species (Platyhelminthes, Monogenea). Parasitology Research 78, 534–6.Google Scholar
Lester, R. J. G. & Adams, J. R. (1974). Gyrodactylus alexanderi: reproduction, mortality and effect on the host. Canadian Journal of Zoology 52, 827–33.Google Scholar
Lynch, M. & Gabriel, W. (1983). Phenotypic evolution and parthenogenesis. American Naturalist 122, 745–64.CrossRefGoogle Scholar
Malmberg, G. (1957). On a new genus of monogenetic trematodes. Arkiv för Zoologie 10, 317–29.Google Scholar
Malmberg, G. (1987). Increased intraspecific divergence in Gyrodactylus salaris resulting from genetic drift in fish farm populations.Åbo Information 19, 33 (Proceedings of the 13th Symposium of the Scandinavian Society for Parasitology, Helsinki, Finland, June 12th–14th, 1987).Google Scholar
Mo, T. A. (1991). Seasonal variations of opisthaptoral hard parts of Gyrodactylus salaris Malmberg, 1957 (Monogenea: Gyrodactylidae) on parr of Atlantic salmon Salmo salar L. in the river Batnfjordselva, Norway. Systematic Parasitology 19, 231–40.CrossRefGoogle Scholar
Mo, T. A. (1992). Seasonal variations in the prevalence and infestation intensity of Gyrodactylus salaris Malmberg, 1957 (Monogenea, Gyrodactylidae) on Atlantic Salmon parr, Salmo salar L., in the river Batnfjordselva, Norway. Journal of Fish Biology 41, 697–707.CrossRefGoogle Scholar
Scott, M. E. (1982). Reproductive potential of Gyrodactylus bullatarudis on guppies (Poecilia reticulata). Parasitology 85, 217–36.Google Scholar