This text was initially printed in Hakai Journal.
Fishers around the globe are determined for a dependable method to cease dolphins from plundering their catch. Dolphins’ web burgling—often known as depredation—prices fishers revenue and in addition places dolphins prone to damage and entanglement. Proposed options, corresponding to utilizing noisemakers, have had combined outcomes. So researchers in Greece went again to the drafting board seeking the right deterrent: one thing so disagreeable that it might keep at bay dolphins and hold them away. They got here up with fishing nets coated with a resin laced with capsaicin, the chemical compound that offers chili peppers their signature warmth.
Giving predators a spicy shock may look like a far-out answer, however capsaicin-based deterrents have proved profitable on land with different mammals corresponding to deer, squirrels, and rodents.
But after 5 months of test-fishing with capsaicin-coated nets, the analysis staff, co-led by Maria Garagouni, a marine biologist at Aristotle College of Thessaloniki, in Greece, got here to a tricky realization: Their concept didn’t work. The bottlenose dolphins that interacted with their nets had been totally unfazed.
Regardless of the disappointing end result, Garagouni says she was wowed by how adept the dolphins had been at pilfering from their nets. Garagouni started collaborating with fishers a decade in the past to review depredation within the Aegean Sea; even so, the animals’ prowess stunned her. When dolphins are available for a netted meal, she explains, it’s greater than a smash-and-grab job: In lots of circumstances, the animals run methodical missions into the nets till they’ve eaten their fill.
“The preliminary shock for me was seeing it occur in actual time,” Garagouni says. The primary time dolphins interacted with the hot-sauce-spiked nets, two people spent not more than quarter-hour tearing 217 holes within the gear.
“After which the victory laps!” Garagouni says. “The play afterwards, when there have been younger calves within the group—after they’d get their fill of fish, the younger ones would go off and do leaps within the air, virtually as if to burn off all this new gas. If this was our livelihood, I believe it might be probably the most infuriating aspect to look at. However for me, clearly, it was wonderful.”
So does this imply dolphins might slurp down Da Bomb Past Madness on their method to Sizzling Ones glory? Aurélie Célérier, a neuroscientist on the College of Montpellier, in France, who makes a speciality of marine-mammal communication and was not concerned within the examine, says it’s too early to make that decision. Though it’s recognized that many cetaceans, together with bottlenose dolphins, lack 4 of the 5 main tastes—they’ll solely choose up salty—spiciness is registered by a unique set of sensory cells by means of chemesthesis. This course of, which alerts sensations corresponding to ache and warmth, is little studied within the species. Different toothed whales do seem to have the {hardware} required for capsaicin detection, Célérier notes, however there’s so much left to study.
There may very well be one thing else at play within the dolphins’ conquer spice: cetacean supersmarts. From corralling fish with plumes of mud to tenderizing powerful prey by tossing it sky excessive, dolphins are recognized for all kinds of clever feeding methods. Their propensity to innovate, mixed with the truth that they’re notoriously unfussy eaters, helps them survive, however it’s additionally partly what places them in rising battle with fishers. The dolphins could merely have discovered a method to break into the spicy nets with out making a lot contact.
The capsaicin coating didn’t deter dolphins, however intriguingly, it did seem to have an effect on one other animal. An unidentified predator, presumably a sea turtle, seal, or shark, tore giant holes within the scientists’ plain management nets however not the spicy nets.
The analysis staff is placing a pin of their red-hot analysis for now, however Garagouni hopes it is going to function a springboard for others on the search to outwit dolphins. Even a examine that fails, she says, presents useful clues and results in new questions.
