Effects of low temperature on the development of the microsporidan Glugea stephani in English sole ( Parophrys vetulus).

Abstract

Glugea stephani requires temperatures >15oC for development in juvenile pleuronectid flatfishes in Yaquina Bay, Oregon. The effect of low temperature (10oC) on the development of recently established parasites was tested in juvenile English sole. Low temperature arrested parasite development, but did not kill the protozoan which resumed development on return to 19-20oC after as long as 42 days at 10oC. No parasites detectable with the light microscope were found in fish examined after 70 days at 10oC. Although most juvenile English sole move permanently from the estuary to cooler ocean waters in the fall and do not contribute to the continuation of the parasite life cycle, the cycle may be maintained by low numbers of English sole that overwinter in the estuary. -from Sport Fishery Abstracts