Discrimination of gyrodactylids based on landmark data

Abstract

First paragraph: There are many different species of the genus Gyrodactylus. One particular form, Gyrodactylus salaris, is known to be highly pathogenic to stocks of Atlantic salmon, whereas other species that infect salmonids have a generally low pathogenicity. Gyrodactylus salaris is responsible for the catastrophic decline in salmon stocks in Norway and has been demonstrated to be widespread in Norwegian rivers. It has also caused problems in Portugal and France. In order to prevent its entry into the UK, G. salaris was made a notifiable disease in 1988 under the 1937 and 1983 Diseases of Fish Acts of the UK. While the UK is thought to be free of G. salaris there is another species, G. thymalli which has been found in the UK and some think is a variant of G. salaris. It is important to find a means of identification of G. salaris via routine microscopic monitoring of samples of parasites. Hence the main motivation for this work is the development of a statistical method which could be used to discriminate G. salaris from other species of Gyrodactylus, while a secondary aim is the discrimination of the other species of Gyrodactylus from each other