One was that, contrary to those fears, both parrotfish and grouper numbers rose sharply.

ECONOMIST: Fishing (I)

This has left parrotfish as the only things preventing beautiful, tourist-friendly coral reefs from becoming slimy seaweed forests.

ECONOMIST: Fishing (I)

More subtly, the rise of the grouper population favoured those species of parrotfish that grow too large for groupers to eat.

ECONOMIST: Fishing (I)

These large parrotfish are also the species that eat most seaweed.

ECONOMIST: Fishing (I)

All in all, the increase in the parrotfish population led to a doubling of grazing on the reef, as well as to an increase in the number of groupers.

ECONOMIST: Fishing (I)

There had been concern that the re-establishment of a predator called the Nassau grouper would lead to a dramatic reduction in the population of parrotfish a group of herbivorous species that feast on seaweed that would otherwise overwhelm the coral.

ECONOMIST: Fishing (I)