What are the wild waves saying?
No one thinks krill are yet endangered, but no one fully understands them. It is known, however, that many whales and seals and penguins live on them. And it is known that the plankton they eat cling to the underside of packed ice, ice that may start melting as temperatures rise. The fear is that devastating the krill population will set in train a series of changes that will affect other creatures. This is, after all, what is happening in other places, though usually the changes start at the apex of the food web. Typically, this is a fish-eat-fish affair, with vegetarians like krill taking their place at the bottom (phytoplankton are plants, whereas zooplankton are animals). Thus the relentless hunting of big sharks off the United States’ Atlantic coast has rendered them unable to “perform their ecosystem role as top predators”, in the words of Julia Baum of Dalhousie University. The upshot is a huge increase in the numbers of their prey, notably ray, skate and smaller sharks. Cownose
