183 research outputs found
Summary of management policies and fisheries regulations for Murray Cod in the Murray-Darling Basin
No full textSand Slugs and fish movement in the Murrumbidgee river: Can you restore and maintain deepwater habitats in sediment-impacted large rivers?
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Recovering threatened freshwater fish in Australia
No full textConcern over the decline of freshwater ecosystems has grown dramatically in recent decades, with major threats of habitat loss or modification, altered flow regimes, changed water quality, barriers to dispersal and migration of biota, and impacts of alien species (Malmqvist and Rundle 2002; Dudgeon et al. 2006). Fishes are a key concern for all of these threats; populations and species are declining globally, with additional threats to fish generated by inappropriate translocation and stocking, and overexploitation. The number of threatened freshwater fish taxa on the IUCN Redlist listed as critically endangered, endangered or vulnerable has increased from 741 in 1996–98 to 2041 in 2012 (version 2012.1; IUCN 2012). Australia has a comparatively small freshwater fish fauna of 256 currently recognised species, of which 74% are endemic (Unmack 2013). However, this species diversity is expected to rise significantly as there are increasing numbers of undescribed and/or cryptic taxa being uncovered through genetic investigations (e.g. Hammer et al. 2007; Raadik 2011). As new species are described, it is increasingly the case that many are already threatened, particularly in southern Australia, where they are often relictual populations with small geographic distributions (e.g. Raadik 2011). The first national list of Australian threatened species in 1980 recognised only 3 freshwater fish species but this has rapidly grown to the 74 species currently on national state or territory listings (Lintermans 2013a). Considerable effort and resources are devoted to recovery of threatened fish species in Australia. Of the 36 freshwater fish listed as nationally threatened, 21 species have national recovery plans, with several additional species having recovery plans in preparation, or covered under recovery plans for threatened ecological communities. To facilitate improvement in the management of recovery programs, review of past and current efforts is essential, but this has not yet occurred for freshwater fish in Australia
Alien salmonids in Australia: impediments to effective impact management, and future directions
No full textAvailable online: 30 Mar 2010Salmonids, 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 southwestern 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.Jean E. Jackson, Tarmo A. Raadik, Mark Lintermans & Michael Hamme
Maccullochella peelii and Maccullochella macquariensis larvae
No full text<p>A photographic comparison of <em>Maccullochella peelii </em>and <em>Maccullochella macquariensis</em> larvae. Selected days from 1- 25 post hatch.</p>
<p>Thanks to NSW Department of Primary Industries, Narrandera Fisheries Centre and Mark Lintermans for larval samples.</p
Managing potential impacts of reservoir enlargement on threatened Macquaria australasica and Gadopsis bispinosus in southeastern Australia
No full textEnlargement of a domestic water supply reservoir on the Cotter River in southeastern Australia (4 to 78 Gl) includes an inundation zone that contains 2 threatened fish species, Macquarie perch Macquaria australasica and two-spined blackfish Gadopsis bispinosus. The enlarged reservoir will be 50 m deeper and impound an additional 4.5 km of river and thus poses a number of potential threats to these fish species. The majority of threats relate to the inundation zone or upstream environments, as downstream environments have been degraded by significant flow alterations from the existing Cotter Dam and 2 upstream dams. Threats include the loss of refuge habitat and associated increased predation, loss of preferred food sources, invasion and expansion of alien fish populations, loss of spawning habitat (or access to it), and the introduction of disease. To minimise or mitigate these threats, a collaborative and comprehensive research and management program is underway involving participation from the water utility and various universities and government agencies. Funding by the water utility of an independent senior fisheries scientist, establishment of a stakeholder steering group, independent peer review processes, and dedicated staff within the design and construction alliance are intended to ensure fish requirements are considered in dam design, construction, and operation. The establishment of an independent, collaborative science-driven process, coupled with the establishment of a long-term monitoring program in an adaptive management framework is a model for other infrastructure projects worldwide, particularly those that threaten riverine fish
Finding the needle in the haystack:comparing sampling methods for detecting an endangered freshwater fish
No full textAccurately detecting the presence or absence of threatened species is vital for threatened species management, and the detection power of individual sampling methods can vary significantly between species and life stages. The present study compares the detection power of six sampling methods in sampling the endangered Macquarie perch in riverine habitats in south-eastern Australia. In an initial survey in 1998 and 1999, fyke nets captured Macquarie perch at 100% of sites where the species was detected; gill-nets captured the species at 86%; with no other method having >50% detection efficiency. Most Macquarie perch were captured by fyke nets (90% in 1998 and 94% in 1999), followed by gill-nets (7 and 2%). A monitoring program at one of the survey sites over 7 years returned similar results with fyke nets detecting the species in all years. Fyke nets captured primarily young-of-year (YOY) individuals, whereas gill-nets captured adults and subadults. Boat electrofishing returned a high level of false negatives for Macquarie perch. Future sampling for this species should employ fyke and gill-nets to adequately characterise population structure (adults, juveniles, YOY), minimise false negatives and detect the occurrence of successful breeding the previous year
First record of the Murray turtle, Emydura macquarii (Gray) (Testudines: Chelidae) from the Australian Capital Territory
No full textVolume: 27Start Page: 38End Page: 4
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