Wildlife at the Watering Hole - June 2026 - Jessica Guerchon

Testing Behavioural Plasticity of Physalia utriculus to Key Environmental Drivers

Jessica Guerchon

Bluebottles (Physalia spp.) are a familiar sight on many coastlines, but when they strand in large numbers, they can cause painful stings and major beach disruptions. Stranding events are strongly associated with winds and surface currents, and forecasting has largely relied on transport models built around these physical drivers. However, Physalia lives at the air-sea interface, where posture, sail exposure, and tentacle deployment may vary under changing surface conditions and, in turn, modulate windage and drift. This talk presents experimental work testing how wind forcing, UV-A irradiance, and seawater temperature shape ecologically relevant behaviours in Physalia utriculus. The aim is to quantify behavioural responses to realistic surface forcing and develop simple behavioural rules that can be incorporated into transport interpretations and models, improving understanding of drift patterns and stranding risk, including potential shifts under changing wind fields and ocean warming. Alongside these experiments, the talk will highlight broader knowledge gaps in Physalia biology and diversity that remain unresolved despite their global occurrence.

Meet our speaker:

Jessica is a PhD candidate at the Centre for Marine Science and Innovation in the School of Biological, Earth and Environmental Sciences at UNSW, where her research focuses on bluebottles and the ecological processes that shape their distribution, drift, and coastal strandings. Her work examines how behaviour, reproduction, morphology, and population dynamics contribute to when and where bluebottles appear along the coast. Her research aims to bridge fundamental understanding of life at the air-sea interface with practical outcomes that support monitoring, risk forecasting, and beach management in a changing ocean.