Prevalence and Morphology of Eimeria gadi (Fiebiger, 1913) in the Haddock

Publisher Website
Google Scholar
Abstract
The coccidian parasite E. gadi was found in the haddock Melanogrammus aeglefinus, taken from the Nova Scotian fishing banks. Haddock infection rates ranges from a high of 58% on Emerald Bank to a low of 4% on Georges Bank, the average being 32%. There was no relationship between sex and degree or prevalence of infection. Although the probability of an occurrence of infection increased with size, small fish with heavy infections were observed. The degree of infection had no apparent effect on the condition factor (length/weight) of the fish. The infection rate reached a maximum in the fall of the year while heaviest infections were in the spring. The infection was fatal. The parasite mass, appearing as a creamy viscous to a yellow semisolid material in the swimbladder, consisted of various parasite stages, fibrous and cellular debris, and lipid material. Some aspects of the sporocyst stage are described. No other gadoids from the Nova Scotian banks were infected; but a single specimen of the fourbeard rockling, Enchelyopus cimbrius, from St. John''s, Newfoundland, was heavily infected with E. gadi.