Publication Abstract

Comparison of the parasites and pathogens present in a cultivated and in a wild population of scallops (Argopecten purpuratus Lamarck, 1819)

Comparison of the parasites and pathogens present in a cultivated and in a wild population of scallops (Argopecten purpuratus Lamarck, 1819)

K.B. Lohrmann A.R. Brand and S.W. Feist

Cultivation of the "ostión del norte", Argopecten purpuratus, is an important economic activity in the 3rd and 4th regions of Chile. Some studies of disease have been undertaken on wild scallops to gather baseline information on healthy populations. However, as cultivated scallops are kept at higher densities than the wild populations, the occurrence and prevalence of parasites may differ. This study compares the types of parasites and their prevalence in wild and cultivated scallops from Tongoy Bay, a major centre for scallop cultivation.

The same parasite taxa, as well as granulomas were found in both populations, but their prevalences differed. The granulomas were small, with no apparent aetiology, but the cultivated population harboured significantly more lesions than the wild population. The only parasites found were a prokaryote and the ciliate protozoan Trichodina sp, found on the gills of the scallops. Trichodina did not seem to elicit a host response and its prevalence was significantly higher in the cultivated scallops. The prokaryote, a rickettsiales-like organism (RLO) was observed as basophilic inclusions in digestive gland cells. At the SEM level they were observed to be rod-like structures of fairly uniform size. The intensity of infection was low, but significantly higher in the wild stock. No host reaction was seen, and the prevalence showed no significant difference between the two populations. The infection with RLOs was therefore independent of the source of the scallops, unlike the Trichodina or the granulomas, which were significantly more prevalent in the cultivated population.

Reference:

K.B. Lohrmann A.R. Brand and S.W. Feist (2002) Comparison of the parasites and pathogens present in a cultivated and in a wild population of scallops (Argopecten purpuratus Lamarck, 1819) Shellfish Research 21:   557 - 561

K.B. Lohrmann A.R. Brand and S.W. Feist*

Shellfish Research 21: 557 - 561