New Zealand Journal of Marine and Freshwater Research abstracts
Alien salmonids in Australia: impediments to effective impact management,
and future directions
Jean E. Jackson
Inland Fisheries Service
P.O. Box 288, Moonah
TAS 7009, Australia
email: Jean.Jackson@ifs.tas.gov.au
Tarmo A. Raadik
Freshwater Ecology
Arthur Rylah Institute for Environmental Research
123 Brown Street, Heidelberg
VIC 3084, Australia
Mark Lintermans
Environment ACT
P.O. Box 144, Lyneham
ACT 2602, Australia
Michael Hammer
School of Earth and Environmental Sciences
University of Adelaide
SA 5000, Australia
Abstract Salmonids, mainly brown and rainbow trout (Salmo
trutta and Oncorhynchus mykiss) were introduced into Australia
in the mid 1860s and early 1890s respectively, and now support economically
valuable recreational fisheries. These alien species have established self-sustaining
populations in many aquatic environments in south-eastern and south-western
Australia, and stocking of hatchery-produced or wild-caught fish in larger
systems is undertaken when fisheries targets are not met (e.g., fish numbers
or appropriate size). Salmonids have established self-maintaining populations
in many waters not targeted or managed as fisheries, colonising the entire
catchment in cooler upland areas of Australia. These populations usually
comprise a high abundance of small fish in small first-to-third-order tributaries.
These waters are infrequently targeted by anglers, and populations may not
contribute individuals to downstream fisheries. Negative impacts of alien
salmonids on native aquatic fauna (including fish, frogs, spiny crayfish),
mainly through direct predation and to a lesser degree competition for resources,
have been noted for over 140 years. Impacts on some faunal groups have been
severe enough to eliminate entire populations and severely fragment species
across their range. Despite these impacts, salmonid management is focused
largely on providing improved recreational angling opportunities, whereas
management of their impacts is almost non-existent. Management of the symptom
of salmonid impacts, i.e., declining native species, begins only after native
species have become imperilled. This paper focuses on impediments to effective
management of salmonid impacts, existing and potential management or control
options, and future directions and research needs.
Keywords salmonids; freshwater biota; impacts; introduced
species; fisheries management
M03092; Received 9 December 2003; accepted 4 May 2004; Online publication
date 3 August 2004
New Zealand Journal of Marine and Freshwater Research, 2004, Vol. 38:
447-455
0028-8330/04/3803-0447 © The Royal Society of New Zealand 2004
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