Meeting Abstract
The Everglades ecosystem is characterized by seasonal rains that expand and reduce habitat available for aquatic organisms. Small fish like Eastern Mosquitofish (Gambusia holbrooki ) move in and out of temporary wetlands each year. Previous field studies have indicated a cyclic change in activity and directionality for some fishes moving across the landscape and that movement rates vary among species. Laboratory experiments were performed to test the hypotheses that the personality, boldness, risk aversion, exploration efficiency and other behaviors related to migration vary among fishes from locations with different hydrology (the Everglades versus Lake Okeechobee) and during different periods of the water year. We found that Eastern Mosquitofish were bolder and were superior explorers of unknown environments during periods of changing water levels. These fish are one of the main resources for wading birds. We performed experiments to determine whether cues from these predatory birds affect how willing the fish are to take on risk of migration, how bold they are and other aspects of their behavior in anticipation of migration. We found that the presence of chemical cues (bird feces) and visual cues (an egret model) increased boldness and the likelihood of exploration by the fish, perhaps indicating that predator risk is one cue used by the fish start migrating. We confirm prior studies showing seasonally changing activity levels by migrating fishes and demonstrate that seasonal changes to personality are partially responsible.
