The ecology of the two-spined blackfish Gadopsis Bispinosus (Pisces: Gadopsidae)
type: CreativeWork
description: The Gadopsidae is an endemic mono-generic freshwater fish family of south-eastern Australia. The family was thought to be mono-specific, containing the River Blackfish Gadopsis marmoratus, until 1984 when a second species, the Two-spined Blackfish G. bispinosus was described (Sanger 1984). Due its relatively recent description, little information was available on the ecology or conservation status of G. bispinosus in NSW and the ACT. The distribution and abundance of G. bispinosus in southern NSW and the ACT was investigated with the species recorded at 16 of 119 sites surveyed. At most sites where they were recorded, G. bispinosus was abundant, and was invariably found in association with one of the trout species. G. bispinosus was found to be restricted to cool, clear upland streams with rocky, cobble bottoms and relatively intact forest vegetation. It was hypothesised that the presence of the species in the upper Murrumbidgee drainage was due to stream capture, in which the headwater streams from the Murray drainage have been captured by the Murrumbidgee drainage. Interpretation of historical reports of blackfish distribution in NSW indicated that G. bispinosus had suffered declines in some rivers with the species now apparently absent from the Yarrangobilly River and the Murrumbidgee, Naas, and Paddys rivers in the ACT. The decline is thought to have been due to habitat degradation, particularly sediment addition, which has reduced the cover available by filling the interstitial spaces in the cobble substrate favoured by G. bispinosus. The invariable association of G. bispinosus with introduced trout species and habitats with abundant cover, suggests that trout may have played some part in the current distribution of G bispinosus by excluding them from sub-optimal habitats. The movements of G. bispinosus was found to be very restricted with a home range of approximately 15 metres estimated for adult fish. Recapture rates were high, particularly in adult fish, in…
abstract: The Gadopsidae is an endemic mono-generic freshwater fish family of south-eastern Australia. The family was thought to be mono-specific, containing the River Blackfish Gadopsis marmoratus, until 1984 when a second species, the Two-spined Blackfish G. bispinosus was described (Sanger 1984). Due its relatively recent description, little information was available on the ecology or conservation status of G. bispinosus in NSW and the ACT. The distribution and abundance of G. bispinosus in southern NSW and the ACT was investigated with the species recorded at 16 of 119 sites surveyed. At most sites where they were recorded, G. bispinosus was abundant, and was invariably found in association with one of the trout species. G. bispinosus was found to be restricted to cool, clear upland streams with rocky, cobble bottoms and relatively intact forest vegetation. It was hypothesised that the presence of the species in the upper Murrumbidgee drainage was due to stream capture, in which the headwater streams from the Murray drainage have been captured by the Murrumbidgee drainage. Interpretation of historical reports of blackfish distribution in NSW indicated that G. bispinosus had suffered declines in some rivers with the species now apparently absent from the Yarrangobilly River and the Murrumbidgee, Naas, and Paddys rivers in the ACT. The decline is thought to have been due to habitat degradation, particularly sediment addition, which has reduced the cover available by filling the interstitial spaces in the cobble substrate favoured by G. bispinosus. The invariable association of G. bispinosus with introduced trout species and habitats with abundant cover, suggests that trout may have played some part in the current distribution of G bispinosus by excluding them from sub-optimal habitats. The movements of G. bispinosus was found to be very restricted with a home range of approximately 15 metres estimated for adult fish. Recapture rates were high, particularly in adult fish, in…
author: Lintermans, Mark
language: en_AU
date published: 1998
date modified: 2026-07-24T01:07:43Z
provider: Australian Catholic University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Australian Catholic University

PropertyValue
property ID: Handle
value: http://hdl.handle.net/1885/10975