Biologists have revealed that while tuna have no negative effect on populations of dolphins, they harbour an intense dislike of other marine mammals, most notably whales.
A three-year study funded by Defra found that tuna exhibit a series behaviours that bear all the hallmarks of an inter-species grudge. They often used their large numbers to block the paths of whales on purpose, preventing them from reaching their traditional feeding grounds. A number of incidents have been reported of whales being driven into shallow water and beached by marauding tuna.
Off the coast of Japan, shoals of tuna were also observed forming giant arrows, signalling the exact position of whales to crews of hunters in the vicinity.
"They just seem to hate the big blubbery bastards," observed one researcher.