ABOVE: Sardines traveling in a large shoal
STEVEN BENJAMIN
They’re a dramatic subject for nature documentaries. In the southern hemisphere winter, swirling masses of silvery Pacific sardines (Sardinops sagax) migrate up the east coast of South Africa into the Indian Ocean—but for some, the trip ends too soon. Along the way, predators such as seabirds and marine mammals feast on the massive collection of fish, often dubbed “the greatest shoal on Earth.”
Indeed, according to a study published September 15 in Science Advances, the KwaZulu-Natal sardine run is an ecological trap: a scenario where the fish’s behavior drives them into an unfavorable habitat that decreases their chances of survival.
“Very little is known about the fate of these sardines,” says Peter Teske, a marine biologist at the University of Johannesburg and one of the authors of the study, in an email to The Scientist. But he and his colleagues conclude that ...
