School of Agriculture, Food and Ecosystem Sciences - Research Publications
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ItemEnvironmental drivers of fish population dynamics in an estuarine ecosystem of south-eastern Australia(WILEY, 2022-10)Abstract Estuaries are dynamic environments and often support rich biodiversity and important fisheries. Linking environmental drivers or events to observed biological changes in these systems provides critical information that can facilitate their management. Historical fish and fisheries data for Western Port, a large embayment in south‐east Australia that supports rich biodiversity, were collated, including catch records, recruitment indices and two novel growth time series. Dynamic factor analysis (DFA) identified three common patterns associated with the biological time‐series data, which in turn were related to both local and regional environmental drivers. On a local scale, nitrogen loads and chlorophyll a concentration affected fish metrics, potentially through the food web and via changes to critical seagrass habitat. On a regional scale, offshore sea surface temperature in Bass Strait was important. Step changes (change points) in the three common patterns were predominantly associated with significant El Niño and La Niña events and, to a lesser extent, recruitment pulses and the cessation of commercial netting.
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ItemThe application of recreational fishing survey data for ecological research, a case study from Western Port, Australia(WILEY, 2020-08)Abstract There is a world‐wide need for information on the ecology and habitat dependencies of important fish species. Recreational fishing surveys represent a potential source of data to increase our knowledge of fish distribution and habitat relationships. Here, a case study is provided on two key recreational species, King George Whiting Sillaginodes punctatus (Cuvier) and Snapper Chrysophrys auratus (Forster). The data came from a recreational fishing survey where 10,978 interviews were conducted from 1998 to 2013 in Western Port, Victoria, Australia. Spatial mapping of catch rate in relation to depth and habitat showed that S. punctatus distribution was related to seagrass cover while C. auratus distribution was related to deeper reef habitat. Juveniles of both species were more abundant in the south‐eastern section of the bay, where water quality is affected by catchment inputs. Overall, the study showed that the inclusion of spatial and habitat information in the design of recreational fishing surveys can significantly increase understanding of the ecology of key species.