Effects of Local Climate on Recreational Fisheries in Central Queensland, Australia: A Guide to the Impacts of Climate Change
William Sawynok and John R. Platten
Abstract .—Central Queensland in Australia already has a highly variable rainfall and streamflow pattern. River flows of the largest local river, the Fitzroy, are seasonal and ephemeral and, between 1976 and 2008, varied in magnitude from around 349,677 to 22,903,390 ML per annum. Predictions of local climate change effects suggest that rainfall and streamflows will become more variable with less frequent but larger flood events and extended, more severe drought periods. SUNTAG is a program that has recorded details of tagged and recaptured fish in Queensland since 1986. CAPREEF is a community-based program that has collected catch-and-effort data from recreational fishers across Central Queensland since 2005. The SUNTAG and CAPREEF programs act as a long-term central repository to collect recreational fish tagging and catch information. The goal of this paper was to examine two models predicting changes associated with rainfall and streamflow, the first examining changes in barramundi Lates calcarifer recruitment in a wetland system and the second predicting changes in recreational catch rate of sand whiting Sillago ciliata and red throat emperor Lethrinus miniatus . Catch rates of young barramundi recruiting to a wetland in the Fitzroy River delta between 1985 and 2008 varied between 0 and 37 fish/d. The median catch rates of fishing clubs also varied widely, being highest in years following wet season flooding.
Catch rates of sand whiting and red throat emperor increased exponentially with flow for above average wet season flows and then declined linearly until the next flood event. Years when wet season flows and local rainfall above a threshold value occurred before March displayed high barramundi recruitment.
Any increase in the length of time between flood events and consequent longer periods of declining catches and reduced barramundi recruitment should be of concern to both fishers and managers.