Foolish Humans! Gulls Are Not So Gullible After All

In the Western Baltic Sea, fisheries target migrating mackerel and needlefish with pound nets, which funnel passing shoals into a series of smaller nets until they are trapped. The traps are emptied every few days, but as the caught fish idle in the nets, they become quite attractive to passing seabirds, such as cormorants, gulls, and terns. The cormorants sample the fish like a charcuterie board and various enterprising gulls steal the cormorants' catches. Several dozen birds can likely be found loitering near any particular pound net, and their ravenous appetites result in real losses for the fisheries. This battle between pound net fishers and seabirds has been ongoing for decades, and fishers have attempted to fight back in various ways. They've tried covering their catch with a netted cover or providing the fish artificial refuges. But the birds are relentless, and the agile cormorants simply entered the pound nets from below. And the more protective netting the fishers added, the more they found tangled or drowned seabirds alongside their catch. A paper from 2021 estimated that 400,000 seabirds are killed by diving into gillnets each year. As such, scientists have been cooking up new strategies to reduce the number of seabirds snacking on and dying in pound nets. They tried high-contrast panels and bright LED lights, but nothing seemed to work. That is, until Bobby the buoy entered the picture. Here is a buoy similar to Bobby: