Active Acoustic Telemetry

This is the depth-profile of a Bonefish spawning event, culminating in the fish ejecting the acoustic telemetry tag during a rapid spawning rush ascent! We used surgically implanted Vemco/Innovasea V9-TP continuous tags and a boat-mounted directional hydrophone, we tracked Bonefish from their nearshore pre-spawning aggregration (PSA) to their deep-water offshore spawning habitat.

We collected bonefish for tagging using a large mesh seine net, hook and line, and fly fishing.

The tracking pole seen here has a directional hydrophone mounted to the bottom. We worked with engineers at FAU Harbor Branch Oceanographic Institute to design a push-pull cable system that allowed us to pivot the forward-facing directional hydrophone straight down, allowing us to maintain signal contact with the fish when they rapidly descended.

In addition to tracking the fish with acoustic telemetry, we used a Sofar Ocean ROV with a custom mounted hydrophone to observe aggregation behaviors and to listen for sounds that the fish may have been using to stay together when offshore.