Environmental drivers of fish population dynamics in an estuarine ecosystem of south‐eastern Australia

Abstract

AbstractEstuaries 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.