Studies on Fish Parasites of Lake Huron and Manitoulin Island

Abstract

The data presented are the result of studies carried on during the summer of 1951. The survey was conducted at the fisheries laboratory of the Ontario Department of Lands and Forests at South Baymouth, Manitoulin Island.* A majority of the fish were obtained from South Bay where many fish were collected as a part of the research studies of the laboratory. Other fish were secured from nets in the open lake near South Baymouth. Fish from several of the Mantoulin Island lakes were obtained by the use of gill nets. Most of the game fish examined for parasites were secured through the cooperation of creel census workers and the line fishermen. The assistance of the laboratory staff was tnuch appreciated in helping to secure hosts for parasite study. Special acknowledgement for aid is given to the director, Dr. Fred E. J. Fry, to John Budd and to James Fraser. In aul, a total of 1,667 fish belonging to 53 different species were examined and 1,642 or 98.5 per cent carried at least one species of parasite. This is quite a high degree of infection due possibly to the fact that most of the hosts were adults and to the high degree that fish carried the encysted metacercariae of eye flukes belonging to the genus Diplostomulum. In other fish parasite surveys the degree of infection has been quite varied, due to many different factors. Bangham and Hunter (1939) reported a 58.3 per cent infection as a result of a study of 2,156 Lake Erie fish belonging to 79 different species. Many were minnows and young fish. The number of parasites was less in hosts from the eastern portions of the lake. In 1944 (unpublished data) the writer found 97.9 per cent of 1,811 northeastern Wisconsin fish from 50 locations to be parasitized. Barigham (1941a) reported 84.3 per cent parasitism for 560 fish belonging to 22 species from Algonquin Park lakes. Bangham and Venard (1942) report 94.9 per cent of 558 fish from Reelfoot Lake parasitized while Bangham (1951) reports 92.3 per cent of 2,351 fish belonging to 14 different species parasitized from the upper Snake River Drainage. Most of the fish were examined while fresh or after being preserved on ice. A few were frozen and examined at a later time. The species of fish are arranged according to the classification of Hubbs and Lagler (1947). Species of parasites are listed in order of frequency of occurrence, the number following eaclh parasite name indicating the number of hosts harboring the form. The degree of infection and distribution are discussed in the text for each species. Encysted larval forms are indicated by a single asterisk (*), while immature stages within the digestive tract are marked by a double asterisk (**).