Extreme boldness precedes starvation mortality in six-lined trumpeter (Pelates sexlineatus)

Fishes are often subjected to seasonal and spatial patchiness of food sources. We tested how risk-taking behaviour in the six-lined trumpeter, an estuarine seagrass resident fish, changed with hunger level in a laboratory experiment. When repeatedly offered a risky source of food, well-fed fish did not approach it and all fish survived over a one-month trial. In contrast, fish deprived of all food boldly first approached the risky food source after only a few days without food in some cases, or after many days in other cases, and then continued to approach risky food each time it was presented. Larger individuals were more bold (and had longer starvation endurance) than smaller ones, and after statistically controlling for these size effects, there were consistent individual differences in the propensity to take risks (i.e. boldness). These results show that food- and individual-dependent boldness will together affect vulnerability to predators and influence predation rates when resources become scarce.