The biomanipulation of aquatic plants and fish was successfully used to restore recreational uses... more The biomanipulation of aquatic plants and fish was successfully used to restore recreational uses of Lake Parkinson, a small (1.9 ha) dune lake, southwest of Auckland, after it had been degraded by introductions of exotic plant and fish species. The oxygen weed Egeria densa was eradicated by stocking a herbivorous fish, the grass carp, Ctenopharyngodon idella. Complete removal of all plants in this lake enabled the subsequent restructuring of its fish fauna. All fish species including the stocked grass carp, rudd (Scardinius erythrophthalmus), tench (Tinca tinca), the native smelt (Retropinna retropinna) and the common bully (Gobiomorphus cotidianus) were removed following application of the piscicide, rotenone. After removal of the grass carp, communities of native macrophytes regenerated from senescent seeds in the lake-bed sediment. The common bully was re-established in the lake by stocking to provide a forage fish for trout. Lake Parkinson now supports a valuable put-and-take t...
Since 1900, a range of anthropogenic stressors has steadily depleted the indigenous fish fauna in... more Since 1900, a range of anthropogenic stressors has steadily depleted the indigenous fish fauna in New Zealand lakes. Efforts to restore these fish populations have involved translocations of small indigenous fish species to replace those reduced by introduced piscivorous fish and elver trap-and-transfer operations over high dams to restore elver recruitment to commercial and customary eel fisheries above the dams. Habitat restoration for small benthic fish (through removal of invasive macrophytes) and for pelagic species (through water quality improvement) has also occurred in lakes, but this was incidental to other management goals and not specifically targeted at native fish restoration. Control of introduced pest fish in lakes is now increasing in importance but is limited in both scope and methods and so is still in its infancy. Overall, there is currently much less focus on indigenous fish restoration in New Zealand lakes and reservoirs than in rivers and streams. Information o...
New Zealand Journal of Marine and Freshwater Research, 1984
... In large, clear, oligotrophic lakes trout fed predominantly on smelt (Retropinna retropinna) ... more ... In large, clear, oligotrophic lakes trout fed predominantly on smelt (Retropinna retropinna) which are shoaling, epipelagic fish. Trout in small turbid lakes fed mainly on the solitary, benthic bully (Gobiomorphus cotidianus). ... Bully (Gobiomorphus cotidianus) ...
SUMMARY 1. To investigate the carrying capacity and factors affecting growth of rainbow trout in ... more SUMMARY 1. To investigate the carrying capacity and factors affecting growth of rainbow trout in Lake Rotoiti, we employed a bioenergetics model to assess the influence of stocking rates, timing of releases and prey abundance on growth and prey consumption. We hypothesised that stocking rates and prey abundance would affect growth and prey consumption by influencing per-capita prey availability, and that the environmental conditions encountered by fish at the time of stocking would affect growth and ...
Proceedings International Conference and Workshop on Engineering of Computer-Based Systems, 1997
... Highly visible prob-lems (not meeting functional requirements, missed per-formance requiremen... more ... Highly visible prob-lems (not meeting functional requirements, missed per-formance requirements, budget and time over-runs, systems integration misfits, etc) are ... Other problems permeate the maintenance and evolution of such systems (short system lifespan, difficulty in ...
The biomanipulation of aquatic plants and fish was successfully used to restore recreational uses... more The biomanipulation of aquatic plants and fish was successfully used to restore recreational uses of Lake Parkinson, a small (1.9 ha) dune lake, southwest of Auckland, after it had been degraded by introductions of exotic plant and fish species. The oxygen weed Egeria densa was eradicated by stocking a herbivorous fish, the grass carp, Ctenopharyngodon idella. Complete removal of all plants in this lake enabled the subsequent restructuring of its fish fauna. All fish species including the stocked grass carp, rudd (Scardinius erythrophthalmus), tench (Tinca tinca), the native smelt (Retropinna retropinna) and the common bully (Gobiomorphus cotidianus) were removed following application of the piscicide, rotenone. After removal of the grass carp, communities of native macrophytes regenerated from senescent seeds in the lake-bed sediment. The common bully was re-established in the lake by stocking to provide a forage fish for trout. Lake Parkinson now supports a valuable put-and-take t...
Since 1900, a range of anthropogenic stressors has steadily depleted the indigenous fish fauna in... more Since 1900, a range of anthropogenic stressors has steadily depleted the indigenous fish fauna in New Zealand lakes. Efforts to restore these fish populations have involved translocations of small indigenous fish species to replace those reduced by introduced piscivorous fish and elver trap-and-transfer operations over high dams to restore elver recruitment to commercial and customary eel fisheries above the dams. Habitat restoration for small benthic fish (through removal of invasive macrophytes) and for pelagic species (through water quality improvement) has also occurred in lakes, but this was incidental to other management goals and not specifically targeted at native fish restoration. Control of introduced pest fish in lakes is now increasing in importance but is limited in both scope and methods and so is still in its infancy. Overall, there is currently much less focus on indigenous fish restoration in New Zealand lakes and reservoirs than in rivers and streams. Information o...
New Zealand Journal of Marine and Freshwater Research, 1984
... In large, clear, oligotrophic lakes trout fed predominantly on smelt (Retropinna retropinna) ... more ... In large, clear, oligotrophic lakes trout fed predominantly on smelt (Retropinna retropinna) which are shoaling, epipelagic fish. Trout in small turbid lakes fed mainly on the solitary, benthic bully (Gobiomorphus cotidianus). ... Bully (Gobiomorphus cotidianus) ...
SUMMARY 1. To investigate the carrying capacity and factors affecting growth of rainbow trout in ... more SUMMARY 1. To investigate the carrying capacity and factors affecting growth of rainbow trout in Lake Rotoiti, we employed a bioenergetics model to assess the influence of stocking rates, timing of releases and prey abundance on growth and prey consumption. We hypothesised that stocking rates and prey abundance would affect growth and prey consumption by influencing per-capita prey availability, and that the environmental conditions encountered by fish at the time of stocking would affect growth and ...
Proceedings International Conference and Workshop on Engineering of Computer-Based Systems, 1997
... Highly visible prob-lems (not meeting functional requirements, missed per-formance requiremen... more ... Highly visible prob-lems (not meeting functional requirements, missed per-formance requirements, budget and time over-runs, systems integration misfits, etc) are ... Other problems permeate the maintenance and evolution of such systems (short system lifespan, difficulty in ...
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