Stock composition and movement of gemfish, <i>Rexea solandri</i>, as indicated by parasites

Abstract

The parasite fauna of gemfish, Rexea solandri, from seven areas off southern Australia, was examined for evidence of isolated gemfish populations. Canonical multivariate analyses of data on larval nematodes (Anisakis spp. and Terranova sp.), cestode plerocercoids (Hepatoxylon trichiuri and Nybelinia sp.), acanthocephalans (Rhadinorhynchus sp. and Corynosoma sp.), and a hemiuroid digenean from a total of 763 gemfish showed that the parasite faunas of fish from eastern Australia were similar except for a sample taken off New South Wales at the end of the spawning season whose affinities are unknown. Fish from South Australia had similar parasite faunas to those collected from eastern Australia, suggesting that fish from the eastern and western Bass Strait belong to the same stock. Fish collected from the Great Australian Bight were distinct from the southern and eastern fish. Differences in parasite fauna were detected between samples taken within the spawning season and those taken from the same locations outside the spawning season, presumably a result of the spawning migration.