In that case, zooplankton populations would rise and the numbers of algae would fall.

BBC: Drug residues 'alter fish behaviour'

This allowed the populations of plankton-eating fish to stage a recovery and compete with the jellyfish for the zooplankton.

BBC: NEWS | Science/Nature | Fishing 'destabilises Black Sea'

DMS. Some let it go only when their cells are damaged as a result of being preyed on by zooplankton.

ECONOMIST: Aerobiology

If perch become more efficient eaters, the numbers of zooplankton will be suppressed which could lead to more frequent algal blooms in waterways.

BBC: Drug residues 'alter fish behaviour'

No-one knows why: theories range from the notion that it might have an antibiotic effect to the idea that it makes algae less appealing to munching zooplankton.

ECONOMIST: Aerobiology

For example, perch eat zooplankton, which in turn consume algae.

BBC: Drug residues 'alter fish behaviour'

But the analysis by Kruta and her colleagues indicates their ammonites would have dined on small organisms floating in the water, such as zooplankton, tiny crustaceans, and even other petite ammonites.

BBC: Ammonite diet revealed in X-rays