Ovivorous Opportunities: Predation Events During Nest Guarding in a Freshwater Fish Species

The construction and defense of nests leading up to and following spawning is widespread across freshwater fishes. Despite the known role of nesting in sexual selection and the establishment of social hierarchy, how nesting and nest guarding behavior may shape predation risk for both offspring and nest guarding individuals remains relatively underexplored for many species. Here, we documented a novel interaction between a nest guarding fish species, the pumpkinseed sunfish (Lepomis gibbosus), and common snapping turtles (Chelydra serpentina) during the pumpkinseed nesting period. Field surveys were conducted over 3 days in an Ontario wetland to document nest densities, predator presence, and predation attempts by potential nest predators. A total of 118 pumpkinseed nests were observed, with all but five nests located in colonies. In nine instances, adult snapping turtles were recorded inspecting guarded pumpkinseed nests. On two occasions, snapping turtles were observed consuming nest contents, as indicated by a gulping motion while on the nest. Male pumpkinseed exhibited defensive behaviors, such as diversion and aggression. Following these interactions, we returned to quantify nest abandonment in three nests and observed that pumpkinseed had abandoned each nest within 48 h. While no observations of predation by snapping turtles on adult sunfish were made, other opportunistic predators made foraging attempts on guarding males. Though nest guarding can improve egg and offspring survival, our results document that predators are still capable of consuming nest contents even while guarded. Omnivorous foraging on fish eggs that are only briefly available to consumers but spatially aggregated in specific spawning habitats and nest colonies warrants future work evaluating the impact of nesting for: (1) adult and offspring survival across systems with divergent predator communities, and (2) the contribution of egg consumption to the seasonal energy budgets of egg predators.