Stock enhancement is an important tool used to rebuild depleted fish populations or enhance recreational fishing. Hatchery-reared individuals can express trait differences, such as growth, which may affect later survival. However, there... more
Stock enhancement is an important tool used to rebuild depleted fish populations or enhance recreational fishing. Hatchery-reared individuals can express trait differences, such as growth, which may affect later survival. However, there is little understanding of how early life growth variation affects stocking success. We examined early life growth of golden perch Macquaria ambigua and assessed how growth within hatcheries affects the survival of stocked fish. We measured daily otolith increment widths at 10, 20 and 30 days after hatching, but before stocking into lakes in south-eastern Australia. Mean growth decreased with age, but variation in growth increased. We then compared the early life growth of these individuals to those recaptured after 2 years at liberty (age-2+). Faster individual growth between 20 and 30 days was positively correlated with increased length at stocking. Mean growth between 20 and 30 days of age-2+ fish was higher than that of young-of-year fish, but among-individual variation in growth did not differ between the two groups. These results suggest that individuals with fast hatchery growth have increased survival to 2 years. We propose that enhancing growth within hatcheries may increase the survival of stocked fish, and thus the cost-effectiveness of fish stocking.
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— The broad‐finned galaxias, Galaxias brevipinnis, spawned during high flows in mid autumn. Spawning took place over inundated riparian areas where eggs were laid amongst substrate, mainly in the interstices of cobbles and pebbles.... more
— The broad‐finned galaxias, Galaxias brevipinnis, spawned during high flows in mid autumn. Spawning took place over inundated riparian areas where eggs were laid amongst substrate, mainly in the interstices of cobbles and pebbles. Between subsequent high flows, eggs were out of water for days or weeks, lying up to 7 m from the water's edge. When exposed, eggs and streamside substrate remained damp, shaded by surrounding forest. Hatching would only occur when eggs were inundated by a subsequent flood. In the field, most eggs had hatched within 30 days of the spawning period, but some remained unhatched for up to 60 days. In the laboratory, eggs remained unhatched for up to 57 days under moist conditions but out of water, and up to 120 days when kept in water. However those kept under drier conditions died. It would appear that riparian cover may be important in providing shaded and moist conditions for the survival of eggs in the wild. Evidence of some adult mortality following spawning was noted. Newly hatched larvae were carried to sea during high flows. Predation on eggs by both adult G. brevipinnis and introduced brown trout Salmo trutta Linnaeus was found to occur.
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The ecology and conservation management of Murray Cod Macullochella peelii peelii, Koehn, John Desmond, Maccullochella, tagging fish, fish larvae, fish surveys, freshwater fishes, fishery conservation, fishery management, freshwater... more
The ecology and conservation management of Murray Cod Macullochella peelii peelii, Koehn, John Desmond, Maccullochella, tagging fish, fish larvae, fish surveys, freshwater fishes, fishery conservation, fishery management, freshwater ecology, Murray-Darling basin, Murray ...
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... De-snagging of the Murray and Murrumbidgee Rivers commenced in 1855 with a boat captain, Francis Cadell, clearing by hand for a little ... construct their burrows where the roots of native vegetation consolidate the banks and prevent... more
... De-snagging of the Murray and Murrumbidgee Rivers commenced in 1855 with a boat captain, Francis Cadell, clearing by hand for a little ... construct their burrows where the roots of native vegetation consolidate the banks and prevent the burrows from collapsing (Serena et al ...
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Common carp (Cyprinus carpio; hereafter carp) is a highly invasive freshwater fish that has colonised river basins across the world causing ecological degradation. In regulated rivers, restoration of natural flow regimes to rehabilitate... more
Common carp (Cyprinus carpio; hereafter carp) is a highly invasive freshwater fish that has colonised river basins across the world causing ecological degradation. In regulated rivers, restoration of natural flow regimes to rehabilitate aquatic ecosystems is a primary focus of environmental management, yet some actions (e.g., environmental water delivery or artificial floodplain inundations) may have unintended consequences including favouring carp. We developed a stochastic population model to represent carp population responses to hydrology and management actions. The model uses current understanding of carp life history, including different survival rates of early life-stages for a range of habitat types, to estimate population responses to various flow/inundation scenarios. Using case studies from two major regions of a large, regulated dryland river, we demonstrate that large natural floods and prolonged droughts accounted for the greatest amplitude of projected carp population...
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Trout cod recovery and management is essentially run by government fisheries and conservation agencies. Successful conservation management and the recovery of Murray cod populations will require the cooperation and support of a range of... more
Trout cod recovery and management is essentially run by government fisheries and conservation agencies. Successful conservation management and the recovery of Murray cod populations will require the cooperation and support of a range of agencies and ...
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... Bernhardt, 2006). This provides a basis for extractive studies in ecohydrology hydroecology, in this way potentially bridging the gap between the traditional subject boundaries of hydrology and ecology (Hannah et al., 2004). In ...
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... Author Contact Information , E-mail The Corresponding Author , Richard J. Barker d , John D. Koehn a , c and Mark A. Burgman b. ... to the diversity of physical habitats created by large wood in rivers, including: pool habitats... more
... Author Contact Information , E-mail The Corresponding Author , Richard J. Barker d , John D. Koehn a , c and Mark A. Burgman b. ... to the diversity of physical habitats created by large wood in rivers, including: pool habitats ([Keller and Swanson, 1979] and [Abbe and Montgomery ...
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Research Interests: Zoology, Biology, Ecology, Fish Biology, Medicine, and 4 moreFisheries Sciences, Fishery, Perciformes, and Perch
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A one‐dimensional hydrodynamic reservoir model is coupled with a stochastic fish population model to examine the impacts of cold water pollution (CWP) on the Australian freshwater fish, Murray cod, downstream of Hume Dam, Australia.... more
A one‐dimensional hydrodynamic reservoir model is coupled with a stochastic fish population model to examine the impacts of cold water pollution (CWP) on the Australian freshwater fish, Murray cod, downstream of Hume Dam, Australia. Mitigation of CWP through the introduction of selective withdrawal capabilities to access near‐surface water is predicted to increase discharge temperatures during the crucial spring‐early summer post‐spawning period by 4–6°C for normal operating conditions, that is, a full reservoir in early spring. No improvement in discharge temperature was predicted for drought conditions characterized by relatively low storage levels in early spring. The predicted temperature increase using selective withdrawal increased the predicted average minimum female population abundance by 30–300% depending on the assumed spawning behaviour. Increased discharge temperatures appear to be achievable and are expected to reduce the stress currently impacting Murray cod populations due to CWP during crucial post‐spawning periods. This provides evidence that mitigation of this problem may assist in rehabilitating Murray cod populations in the Murray River downstream of Hume Dam. Copyright © 2007 John Wiley & Sons, Ltd.
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Freshwater biodiversity is under great threat across the globe as evidenced by more severe declines relative to other types of ecosystems. Some of the main stressors responsible for these concerning trends is habitat fragmentation,... more
Freshwater biodiversity is under great threat across the globe as evidenced by more severe declines relative to other types of ecosystems. Some of the main stressors responsible for these concerning trends is habitat fragmentation, degradation, and loss stemming from anthropogenic activities, including energy production, urbanization, agriculture, and resource extraction. Habitat protection and restoration both play an integral role in efforts to save freshwater biodiversity and associated ecosystem services from further decline. In this paper, we summarize the sources of threats associated with habitat fragmentation, degradation, and loss and then outline response options to protect and restore freshwater habitats. Specific response options are to legislate the protection of healthy and productive freshwater ecosystems, prioritize habitats for protection and restoration, enact durable protections, conserve habitat in a coordinated and integrated manner, engage in evidence-based res...
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A range of perspectives is presented from the International Fisheries Section of the American Fisheries Society on climate change effects on inland fisheries from standing and flowing waters in Africa, Asia, Australia, Europe, and Latin... more
A range of perspectives is presented from the International Fisheries Section of the American Fisheries Society on climate change effects on inland fisheries from standing and flowing waters in Africa, Asia, Australia, Europe, and Latin America.
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... USDE Bonneville Power Administration, DOE/BP-2 1493-1, Portland, OR. Bilby RE, Ward JW, 1991. ... Gippel CJ, O'Neill IC, Finlayson BL, Schnatz I. 1996b. Hydraulic guidelines for there-introduction and management of... more
... USDE Bonneville Power Administration, DOE/BP-2 1493-1, Portland, OR. Bilby RE, Ward JW, 1991. ... Gippel CJ, O'Neill IC, Finlayson BL, Schnatz I. 1996b. Hydraulic guidelines for there-introduction and management of large woody debris in lowland rivers. ...
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ABSTRACT