Sir

Your News feature on fisheries management (Nature 419, 662; 2002) raises the important point of considering each fishery in the context of its larger ecological context, although you identify overfishing as the root cause of fisheries depletion. This perspective puts the onus of fisheries health exclusively on the fishing industry. Agricultural runoff, the pollution and disappearance of estuarine and wetland nurseries and, increasingly, anthropogenic 'noise' are all compromising ocean health — to such a degree that fisheries population crashes might occur even without commercial overharvesting.

Only recently has anthropogenic noise been acknowledged as a threat to marine ecology, as evidenced by whale and dolphin strandings caused by military sonar (Nature 415, 106; 200210.1038/415106a). Noises caused by shipping, underwater seismic exploration, sonar, underwater telemetry and military exercises have all increased dramatically over the past decade. Many fish rely on acoustical perception to hunt, school, evade predators and find mates. Cluttering their acoustical niches with noise affects their survival prospects.