Skip to main content
Log in

Halotolerance of the oyster predator, Imogine mcgrathi, a stylochid flatworm from Port Stephens, New South Wales, Australia

  • Published:
Hydrobiologia Aims and scope Submit manuscript

Abstract

The stylochid flatworm, Imogine mcgrathi was confirmed as a predator of the pteriid oyster Pinctada imbricata. Occurring at an average of 3.2 per oyster spat collector bag, the flatworms were found to consume oysters at a rate of 0.035–0.057 d−1 in laboratory trials. Predation was affected by flatworm size with larger worms capable of consuming larger oysters and of consuming greater dry weights of oyster flesh. Irrespective of flatworm size, predation was generally confined to oysters less than 40 mm in shell height. Although all predation occurred at night, shading flatworms during the day did not significantly increase the rate of predation, but there were significant increases in the dry weight of oyster meat consumed. As a means of controlling flatworm infestations, salt, brine baths (250 g kg−1) and freshwater baths were effective in killing I. mcgrathi. The ease of use of hyper- or hyposaline baths then encouraged assessments of I. mcgrathi halotolerance. The flatworms were exposed to solutions ranging in salinity from 0 to 250 g kg−1for periods of from 5 min to 3 h. Despite showing both behavioural and physiological signs of stress, I. mcgrathi survived the maximum exposure time of 3 h at salinities in the range 7.5–60 g kg−1, inclusive. Beyond this range, the duration of exposure tolerated by flatworms decreased until 0 and 250 g kg−1, at which the flatworms no longer survived the minimum tested exposure of 5 min. Thus, despite the significant impact of other stylochids on commercial bivalves, at their current prevalence, I. mcgrathi can be controlled by exposing them to hyper- and hyposaline baths for the culture of P. imbricata in Port Stephens, NSW, Australia.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Bardach, J. E., J. H. Ryther & W. O. Mclarney, 1972. Aquaculture; The Farming and Husbandry of Freshwater and Marine Organisms. Wiley Interscience, London: 868 pp.

    Google Scholar 

  • Chintala, M. M. & V.S Kennedy, 1993. Reproduction of Stylochus ellipticus (Platyhelminthes: Polycladida) in response to temperature, food and presence or absence of partner. Biol. Bull. 185: 373–387.

    Google Scholar 

  • Dakin, W. J., 1952. Australian Seashores, Angus and Robertson Publishers, Sydney: 372 pp.

  • Espinosa, J., 1981. Stylochus megalops (Platyhelminthes: Turbellaria), Nuevo depredadror del ostion en Cuba. Poeyana 228: 1–5.

    Google Scholar 

  • Galleni, L., P. Tongiorgi, E. Ferrero & U. Salghetti, 1980. Stylochus mediterraneus (Turbellaria: Polycladida), predator on the mussel Mytilus galloprovincialis. Mar. Biol. 55: 317–326.

    Google Scholar 

  • Heasman, M. P., W. A. O'Connor, S. J. O'Connor & W. W. Walker, 1998. Enhancement and Farming of Scallops in NSW using Hatchery Produced Seedstock. NSW Fisheries Final Report Series, No 8: 146 pp.

  • Hyman, L.,1951. The Invertebrates: Platyhelminthes and Rhynchocoela. The Acoelomate Bilateria. Vol. II, McGraw-Hill New York, NY: 550 pp.

  • Hynd, J. S., 1955. A revision of the Australian pearl shells, genus Pinctada (Lamellibranchia). Aust. J. mar. Freshwat. Res. 6: 98–137.

    Google Scholar 

  • Jennings, K. A. & L. J. Newman, 1996. Four new stylochid flatworms (Platyhelminthes: Polycladida) associated with commercial oysters from Moreton Bay, southeast Queensland, Australia. Raffles Bull. Zool. 44: 493–508.

    Google Scholar 

  • Korringa, P., 1976. Farming the Cupped Oysters of the Genus Crassostrea. Elsevier, Amsterdam, The Netherlands: 224 pp.

    Google Scholar 

  • Landers, W. S. & E. W. Rhodes Jr, 1970. Some factors influencing predation by the flatworm Stylochus ellipticus (Girard), on oysters. Chesapeake Sci. 11: 55–60.

    Google Scholar 

  • Landers, W. S & R. C. Toner, 1962. Survival and movements of the flatworm Stylochus ellipticus in different salinities and temperatures. Biol. Bull. 123: 146–153.

    Google Scholar 

  • Lin, S. J., T. J. Chai, S. S. Jeng & D. F. Hwang, 1998. Toxicity of the puffer Takifugu rubripes cultured in Northern Taiwan. Fish. Sci. 64: 766–770.

    Google Scholar 

  • Littlewood, D. T. J. & L. A. Marsbe, 1990. Predation on cultivated oysters, Crassostrea rhizophorae (Guilding) by the polyclad turbellarian flatworm Stylochus (Stylochus) frontalis Verrill. Aquaculture 88: 145–150.

    Google Scholar 

  • Newman, L. J. & L. R. G. Cannon, 1995. The importance of the fixation of colour, pattern and form in tropical Pseudocerotidae (Platyhelminthes, Polycladida). Hydrobiologia 305: 141–143.

    Google Scholar 

  • Newman, L. J., L. R. G. Cannon & H. Govan, 1993. Stylochus (Imogene) matatasi n. sp. (Platyhelminthes, Polycladida): pest of cultured giant clams and pearl oysters from Solomon Islands. Hydrobiologia 257: 185–189.

    Google Scholar 

  • Pearse, A. S. & G. W. Wharton, 1938. The oyster 'leech' Stylochus inimicus Palomi, associated with oysters on the coast of Florida. Ecol. Monographs 8: 605–655.

    Google Scholar 

  • Shirai, S., 1994. Pearls and Pearl Oysters of the World. Marine Planning Company, Okinawa, Japan: 108 pp

    Google Scholar 

  • Stead, D. G., 1907. Preliminary note on the wafer (Leptoplana australis) a species of dendrocoeleous turbellarian worm, destructive to oysters. New South Wales Department of Fisheries, Sydney, NSW, Australia: 6 pp.

    Google Scholar 

  • Yang, H. C., 1974. On the extermination of polyclads: calcium hypochlorite (CaOCl2) treatment in the period of high water temperature. Bull. Korean Fish. Soc. 7: 121–125.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

O'Connor, W.A., Newman, L.J. Halotolerance of the oyster predator, Imogine mcgrathi, a stylochid flatworm from Port Stephens, New South Wales, Australia. Hydrobiologia 459, 157–163 (2001). https://doi.org/10.1023/A:1012525015850

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1023/A:1012525015850

Navigation