What is the most popular time for sharks to be on the move?
A new study involving a popular transportation route in between Hawaii and American Samoa in the Pacific Ocean aimed to seek when sharks were most likely to be out and about. Among one of the most important areas of interest was a lagoon located inside of a ring of coral islands known as Palmyra Atoll.
The UC Santa Barbara biologist team used high-resolution acoustic cameras designed for the Navy that utilize dual-frequency sonar to keep track of shark movement underwater throughout what appeared to be a very active transportation channel for various species, whether they were sharks, turtles, or even manta rays.
Image Credit: UCSB
The sonar-based device essentially created a sound gate that sharks could swim through, and using this method of observation, the researchers spent a good 443 hours of time throughout the course of a month observing traffic patterns.
The research was published in the Journal of Experimental Marine Biology and Ecology.
The route is described in the study as a “highway” for the animals, as they try to get from point A to point B, but perhaps the most interesting piece of information that can be gathered from it is that 7-8 P.M. local time seemed to be the busiest time for sharks.
“My research team and I have spent a lot of time on Palmyra around this particular feature, but it wasn’t until we were able to light up that world and extract data that we discovered this huge rush hour of sharks in the evening,” said lead author Douglas McCauley, an assistant professor for UC Santa Barbara. “This matters. It’s important to know for how we deal with sharks and to determine their behavior patterns.”
Effectively, we can gather that this is their ‘rush hour,’ just like the 5-6 P.M. commute home from work on the highway when there are more cars on the road then than later at night or earlier in the afternoon.
The traffic observations performed by the team is actually far more important than just the numbers obtained; it also shows that this kind of technology is a great alternative for the otherwise tricky task of monitoring underwater animal traffic.
Namely, it could help scientists who are trying to track sharks for various reasons, whether it’s to protect endangered species, track their patterns and numbers, or to better understand their behavior.
“Sharks are in trouble worldwide, so we need to be thinking about new tools and new technologies for studying them, and this one — which wasn’t designed for scientific applications — worked very well,” said McCauley.
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Source: UC Santa Barbara