Swimming against the flow-Environmental DNA can detect bull sharks () across a dynamic deltaic interface.

Human activities in coastal areas are accelerating ecosystem changes at an unprecedented pace, resulting in habitat loss, hydrological modifications, and predatory species declines. Understanding how these changes potentially cascade across marine and freshwater ecosystems requires knowing how mobile euryhaline species link these seemingly disparate systems. As upper trophic level predators, bull sharks () play a crucial role in marine and freshwater ecosystem health.