The saying goes: give a human a fish, you feed them for a day. Teach a human to fish, and you’ll feed them for a lifetime – unless, that is, some orcas swipe your catch. Apparently, they’re not only capable of stealing from boats and fisheries but are actually teaching each other to do so, at least that’s the takeaway from a recent study looking at orcas off the coast of the Crozet Islands in the southern Indian Ocean.
Published in the journal Biology Letters, the paper set out to explore if the behavior of stealing from boats and fisheries was becoming more common as the ocean’s resources grow more depleted. Intelligent orcas have long been nicking (or reclaiming, depending on your outlook) seafood from humans, but if it was becoming a more common and widespread way of finding food was unclear.
To find out, the study looked at 16 years’ worth of monitoring data stretching from 2003 to 2018 that focused on two subantarctic populations of killer whales (Orcinus orca). Information included within the dataset enabled them to assess changes in the number of orca “depredation” events, where they essentially took fish back from fishing nets, lines, or accessible catch.
“In subantarctic waters, the expansion of commercial [fishing] targeting Patagonian toothfish, Dissostichus eleginoides, in the 1990s was [associated] with killer whale depredation occurring in most fisheries, from southern Chile to the southern Indian Ocean,” wrote the study authors.
“The incidence of this behaviour is highest around the Crozet Islands, where killer whales were reported depredating in the first year of the fishery in 1996 and currently take approximately 180 tonnes of toothfish from longlines every year.”
Since that first depredation record, reports of orca theft for both populations steadily increased, which the researchers say can’t be accounted for as a result of the number of orcas increasing. Instead, they suggest it’s indicative of more of the existing orcas learning how to steal from fisheries.
The increasing rate of depredation events saw a plateau in 2014, which could indicate that it took 18 years for the whole population to catch onto the behavior after the first report of orca theft in the area back in 1996.
The route of spread? Orca fishing lessons, it seems, as these highly social and intelligent marine mammals are more than capable of strategizing when it comes to finding food. Recent research has confirmed that they’re even able to club together and take down the world’s largest animal, but why bother when you can steal from humans?
“These findings show how changes in prey availability caused by human activities lead to rapid, yet progressive, innovations in killer whales,” concluded the study authors, “likely altering the ecological role of this top-predator.”