Sailfish are generally known as the fastest fish in the sea. As such, researchers have had an extraordinarily tough time studying them, especially when it comes to their solo hunting habits. But students at Nova Southeastern University’s Guy Harvey Research Institute (GHRI) designed a piece of tech that made it a lot easier to find out more about those habits.
Sailfish, if you’re not in the loop, are very distinctive. They have huge dorsal fins and a stretched out front-end bill that acts as a sword when hunting. They spend most of their time in the open ocean, both in large groups and alone. When hunting in groups, they school the fish, then use their bill to hack and stun their prey. While that kind of hunt has been observed multiple times (it generally happens near the surface of the ocean), the lone hunter had never been captured on film.
“Because you can’t keep a sailfish in captivity, we know surprisingly little about their basic biology,” said Ryan Logan, the lead author of the study and a doctoral candidate and research associate at NSU’s GHRI in Davie, Florida. “For instance, how much food do they need on a daily basis to survive?”
Sailfish can be solitary creatures. They also have a few interesting characteristics that led scientists to believe that they must hunt alone.
“For example, they can keep their eyes and brain warmer than the surrounding water, which gives them an advantage over their prey when hunting in colder or dimly lit water,” wrote the authors of the study published in the journal Nature. “But because of this, it’s assumed that they burn a lot of calories throughout the day, so one could assume that they must also need to eat in between those group hunting events, although this had never been documented.”
In an attempt to learn how long it took a sailfish to recover after it had been released when caught by sport fishers, the researchers at GHRI designed an electronic tagging device equipped with high-tech sensors and a video camera to capture that hard-to-get footage. They headed out to southwest Panama, which is one of the world’s best fishing spots, caught a sailfish, tacked on the device, and let it go.
While they did indeed get the answer to their initial question, the researchers were also treated to a pleasant surprise when the cameras kept rolling. The video shows a 100-pound sailfish shooting towards the surface from around 200 feet down. It moves at an incredible rate of speed towards a small tuna lurking near the surface. After several attempts, it appears to catch its prey before returning to business as usual.
The video helps researchers to understand more about the sailfish, which is an important species for both the ecosystem and for fishing tourism companies.
“This research improves our understanding of the hidden lives of these majestic, ecologically and economically very important fish,” said Mahmood Shivji, Ph.D., a co-author of the study and Director of NSU’s GHRI. “Such knowledge is essential to help us better protect the health of these fish and their prey to have a sustainable sportfish industry for many years to come.
