Can New Technology Improve Our Understanding of Anadromous Fish Behavior?

Rillahan, Chris*, Pingguo He, University of Massachusetts Dartmouth, SMAST, New Bedford, MA

Estuaries are dynamic environments filled with a diversity of sea life. Many commercially, recreationally or culturally important fish species, including striped bass and river herring, rely on these ecosystems. Their complex life histories drive complex behaviors which are still not well understood. The adoption of new technology and analysis methods start to challenge our existing paradigm of fish behavior and movement in the ecosystem. Our research uses high-resolution acoustics to study the fine-scale behavior of river herring and striped bass during the annual herring spawning run. The data indicates that both striped bass and river herring exhibit complex behaviors during this period. River herring have exhibited preferential movement based on the time or day, tidal state, and interaction between the two. The result was shifting periodicity of movement through the spawning season to correlate with preferred movement conditions. These behaviors indicate that predation may be the primary driving factor early in the migration. Conversely, striped bass were observed to selectively reside downstream of the Herring River dyke, presumably to maximize their foraging success. The results indicate that behavior is the result of complex biological, ecological, and environmental interactions which have significant implications toward species monitoring, management and conservation.