Blue cod in New Zealand’s Marlborough Sounds were squeamish during a recent research project in which scientists used lasers to research the species (Parapercs (charcoal) in the region. Reviewing the footage, the team discovers that the blue cod is doing a strange cat-like thing – they start chasing the lasers.
“When trying to count and measure the blue cod, we saw that they were chasing our lasers, just like cats do!” National Institute of Water & Atmospheric Research Ltd (NIWA) marine ecology technician Charlotte Bodie said in a statement emailed to IFLScience. “I’ve seen a lot of underwater footage in my time, but I’ve never seen anything like this. No other species seems to do this.”
It may be a first for the New Zealand team, but it’s a behavior that has also been seen among wrasse in England.
“It definitely breaks up the monotony of the job,” Bodie continued. “We do a lot of video analysis and see a lot of interesting and unique fish behavior, but unfortunately we don’t have time to investigate everything.”
Although a humorous comparison to cats’ fascination with laser pointers, it did not hold up well under experimental conditions. NIWA technicians try to measure the size of the cod, as well as their numbers, but getting an accurate reading isn’t easy with all the kittens around.
“It made it difficult for us to count blue cod because they tend to group together and follow the lasers,” explained NIWA marine ecology technician Brooke Madden, “but it also meant we could measure the fish more accurately because they swim closer to the lasers.”
The New Zealand blue cod is a heavy specimen, weighing up to 3 kilograms (6.6 pounds) and reaching up to 60 centimeters (23.6 inches) in length. As protogynous hermaphrodites, they can change their sex from female to male, and the team’s current project – funded by Fisheries New Zealand – hopes to shed light on the species’ juvenile habitats.
Why fish are so keen on chasing lasers is a scientific discovery for another study – but these strange creatures are certainly equipped for zooming in on small targets.
“They are very inquisitive fish with large lateral eyes that can rotate independently, allowing them to see almost anywhere around them,” Bodie concluded. “Finding out why they chase lasers like cats could make a great project someday.”
Playing lasers with blue cod, but make it science? Count us in!
