Two fisheries in the Severn Estuary are to be closed under plans by the Environment Agency to conserve salmon stocks.
Fisheries will be compensated if they have to close
The action plan is one of several being produced for all the principal salmon rivers in England and Wales.
Dr John Woolland from the agency said the Severn plan needed to "achieve a balance" between preserving traditional skills and ensuring future supplies.
Those who stand to lose their livelihoods have been assured they will receive compensation.
If measures to protect the fish are not taken, the agency says salmon numbers could decline to the extent that some fisheries may disappear altogether.
The Severn Estuary Salmon Action Plan is the only such plan in the UK created specifically for an estuary.
Salmon caught by the commercial fishery in the estuary are on their way back to spawning grounds and may be returning to rivers such as the Wye, where poor stocks are causing concern.
As well as closing some fisheries, the plan recommends creating more fish passes, which enable salmon to reach the upstream spawning grounds more easily.
Nursery and spawning areas will be improved and the agency will assess the impact of predators, such as birds.