Recognition that many species share key life-history strategies has enabled predictions of responses to habitat degradation or rehabilitation by these species groups. While such responses have been well documented for freshwater fish that exhibit 'periodic' and 'opportunistic' life-history strategies, this is rare for 'equilibrium' life-history, due largely to their longevity and by comparison, more regular and stable levels of recruitment. Unfortunately, this limits the confidence in using life-history strategies to refine water management interventions to rectify the negative impacts of river regulation for these species.
View Article and Find Full Text PDFThe construction of dams and weirs, and associated changes to hydrological and hydraulic (e.g., water level and velocity) characteristics of rivers is a key environmental threat for fish.
View Article and Find Full Text PDFMost assessments of the effectiveness of river restoration are done at small spatial scales (<10 km) over short time frames (less than three years), potentially failing to capture large-scale mechanisms such as completion of life-history processes, changes to system productivity, or time lags of ecosystem responses. To test the hypothesis that populations of two species of large-bodied, piscivorous, native fishes would increase in response to large-scale structural habitat restoration (reintroduction of 4,450 pieces of coarse woody habitat into a 110-km reach of the Murray River, southeastern Australia), we collected annual catch, effort, length, and tagging data over seven years for Murray cod (Maccullochella peelii) and golden perch (Macquaria ambigua) in a restored "intervention" reach and three neighboring "control" reaches. We supplemented mark-recapture data with telemetry and angler phone-in data to assess the potentially confounding influences of movement among sampled populations, heterogeneous detection rates, and population vital rates.
View Article and Find Full Text PDFJ Environ Manage
October 2013
Fish habitat restoration efforts frequently involve the reintroduction of instream woody habitat (IWH) in areas where large scale removal has taken place over time. Identifying areas of low IWH density for reintroduction requires a 'current state' spatial representation of the IWH densities that is traditionally a labour intensive and costly exercise. We present a meso-macro scale assessment procedure that incorporates a rapid on-ground field survey method with a novel analytical approach to map IWH densities.
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