Parasites as Potential Biological Tags of Atlantic Salmon (Salmo salar) smolts in the Miramichi River System, New Brunswick

Abstract

Ten parasite species (one protozoan, eight helminth, one mollusc) were collected from 1262 smolts of Atlantic salmon (Salmo salar) in the eight tributaries and estuary of the Miramichi River, New Brunswick, Canada during 1970 and 1971. Three of these parasites, Discocotyle sagittata, Diplostomum spathaceum, and Neoechinorhynchus rutili showed restricted distributions within the study area. Discocotyle sagittata infected 32.6% of 435 smolts collected from tributaries draining into the Main Northwest Miramichi River but only 0.3% of 604 smolts collected from tributaries draining into the Main Southwest Miramichi River. Diplostomum spathaceum infected 18.9% of 148 smolts collected from the Southwest Miramichi River but was absent in 819 smolts collected from the remaining tributaries. Neoechinorhynchus rutili infected 18.8% of 144 smolts collected from the Bartholomew River but only 0.2% of 895 smolts collected from the other tributaries. Presence of Discocotyle sagittata on smolts collected in the estuary of the Miramichi River would identify smolts that originated in the Main Northwest Miramichi River, thus allowing for a separation of smolts from this branch and the other main branch, the Main Southwest Miramichi River. Presence of Diplostomum spathaceum in smolts collected in the Main Southwest Miramichi River or in the estuary of the Miramichi River would identify smolts that originated in the Southwest Miramichi River. Presence of N. rutili in smolts collected in the Main Southwest Miramichi River would identify smolts of Bartholomew River origin.