Abstract
Sea mullet (Mugil cephalus) are the most widely distributed species within the family Mugilidae, occurring in all major oceans. Recent declines in catch rates of M. cephalus in the Great Sandy Straits, an important southeast Queensland (SEQ) biosphere, have raised concerns about stock abundance. Typical environmental baselines relating to temperature and other abiotic factors are changing rapidly in this climate change hotspot. Here, we investigate commercial fishery catch per unit effort (CPUE) data in both the Great Sandy Straits and nearby Moreton Bay region in relation to several environmental variables using generalised additive models (GAMs). Results indicate that increasing water temperature has negatively influenced the CPUE of M. cephalus, while distance from the river mouths positively influenced the catch rates in both regions. As coastal sea surface temperatures are projected to increase by approximately 1°C, these observed temperature increases may have resulted in a persistent significant decline in CPUE, while 200km to the south, cooler Moreton Bay waters produced increases in CPUE over the same period. These findings indicate a potential shift in M. cephalus movements to spawning areas in SEQ and emphasise the need for adaptive fisheries management strategies for target species in sub-tropical climate change hotspots.