Keri Anne Goncalves will be defending her thesis on “Co-occurrence of White Sharks (Carcharodon carcharias) Along Coastal Cape Cod, MA” on March 18th at 2 pm! Join us in person at SMAST East 101-103  or on Zoom!

 

Abstract:

Periodic aggregation and site fidelity are common occurrences for many terrestrial and aquatic species and is typically driven by resource availability. The white shark (Carcharodon carcharias) is a species driven by such, with aggregation behavior throughout multiple stages of its life history. Juveniles exhibit resource-driven aggregations at nursery sites where they may reside for extended periods of time. Large juveniles, sub-adults, and adults tend to exhibit seasonal residency at aggregation sites along their migration routes. Atlantic white sharks form distinct communities during critical early phases of life, though little is known of spatiotemporal trends during late life stages. Using a five-year acoustic telemetry dataset from eastern Cape Cod, MA, this study investigated spatiotemporal associations between tagged individual white sharks (n=185). Network analysis was applied to acoustic detection data (n=365,880 detections) collected seasonally from 2017-2021 to identify strength of associations between groups or individuals. These analyses revealed sexual segregation and behavioral avoidance over the course of the five-year study. In each year and across all years combined aggregating sharks exhibited overall significant negative co-occurrence patterns. This study finds notable interannual variations in social dynamics as well as associations among male and female sharks across multiple years emphasizing the possibility of sex-specific variations in social behavior.