Ocean Watch: Cod Killers

Georges bank, its once teeming schools of cod and haddock nearly exhausted from overfishing, was partially closed to commercial trawlers ten years ago. Fish are still scarce in those New England waters, but one tiny inhabitant of the bank is flourishing. More than a trillion tentacled organisms called hydroids are adrift there. Despite their diminutive size, the hydroids threaten the recovery of Georges Bank. Hydroids feast on the same foods favored by larval cod and haddock. More ominously, hydroids also consume young fish.