Researchers from Nova Southeastern University’s Guy Harvey Research Institute have used sensors for the first time to track what happens to billfish after they’re caught for sport and then released back into the wild.
While the fish are renowned among sport fishers for putting up a “good fight,” nothing is known about what happens to them after they are released. Do they recover, and if so, how quickly, or do they just die from the exhaustion of being caught?
Researchers used tracking technology to see what happened to blue marlin and sailfish that were caught at one of the world’s best-known fishing locations, Tropic Star Lodge in Panama. The findings were quite surprising and showed the fish swimming harder after being released since they needed to get more water flowing over their gills to extract more oxygen from it and “catch their breath” — the exact opposite of what humans do.
According to doctoral candidate and research associate at NSU’s GHRI Ryan Logan:
“For the angler, a billfish fight consists of a fast-paced, high-energy battle of wills that hopefully culminates with a fishing-line leader grab and a safe release of the fish, some high fives, rehydration, and re-setting the spread for the next one…For the fish, on the other hand, this is a fight for its life using a tremendous amount of energy, and it was those high-speed runs and aerial acrobatics that made me wonder: how long does it take them to physically recover from that fight after being released?”
“We used an inertial measurement unit (IMU), which integrates multiple sensors including multi-axes accelerometers, gyroscopes, and magnetometers to provide estimation of an object’s orientation and movement in space…Sounds very technical, but most people are likely to have one of these units in their pocket or on their wrist right now. They are used in nearly all modern electronics for a variety of purposes, such as telling your cell phone screen to rotate when you turn the device sideways, or how your watch counts how many steps you take and how many calories you burn throughout the day.”
You can find the original study here.