Migratory river fish populations plunge 76% in past 50 years

Decline in species such as salmon harms entire ecosystems and livelihoods, say researchers

Populations of migratory river fish around the world have plunged by a catastrophic" 76% since 1970, an analysis has found.

The fall was even greater in Europe at 93%, and for some groups of fish, with sturgeon and eel populations both down by more than 90%.