Eventually, he and his colleagues gathered more than 2,200 data points on 399 prey species from every ocean and all the continents except Antarctica. Inspired by this ecological disconnect, Reimchen began collecting data from other studies that had looked at predators, including humans, and the characteristics of the prey they were consuming. “This situation contrasted dramatically with the commercial fishing I observed in adjacent marine waters, which were taking from 40 to 80 percent of the biomass of salmon and herring, and then predominantly the reproductive-age classes,” Reimchen recalled at a telephone press conference held on Wednesday. This was because the predators overwhelming consumed fry, juveniles and sub-adults, eating only 5 percent of the reproductively valuable adults each year. Despite the number of predators, the stickleback population remained steady. There, 22 species of trout, loons and other predators fed on stickleback fish. The new study got its start back in the 1970s, when Thomas Reimchen of the University of Victoria was studying predator-prey interactions in a remote Canadian lake. “Depleting the capital is risky, particularly in long-lived, late-maturing organisms.” “Adult individuals provide the ‘reproductive capital’ of a population, akin to the financial capital in a bank account or retirement fund,” Dalhousie University biologist Boris Worm notes in a commentary that accompanies the study, published today in Science. Humans, by contrast, are far more likely to be killing big strapping adults, particularly among carnivores on land and fish in the ocean. Across the animal world, predators focus their efforts on juveniles. The human species really is unlike any other predator on the planet, especially when it comes to our choice of prey.