UK fishing fleets may soon have to use hi-tech equipment to keep dolphins and porpoises out of their nets.
By Alex Kirby
BBC News Online environment correspondent
Ministers are considering the obligatory use of pingers, acoustic warning devices to alert the cetaceans.
They are also trying a new sort of net with a panel to allow larger marine creatures to escape.
The initiative aims to cut the rate of cetacean deaths from their present unsustainable level.
Eliot Morley, the UK Fisheries Minister, announced the proposals, which are the subject of public consultation for three months.
Mr Morley's ministry, the Department for Environment, Food and Rural Affairs (Defra), has published a consultation document, UK Small Cetacean Bycatch Response Strategy.
It aims to see how to reduce bycatch (the accidental catching of species which are not targets) "to below the 1.7% target set by Ascobans (the Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas) in 2000".
Small cetaceans found in UK waters include harbour porpoises, six dolphin species (common, bottlenose, white-beaked, Atlantic white-sided, striped, and Risso's), and pilot and killer whales.
The numbers found stranded on UK shores are rising, though by no means all have died as bycatch:
From 1 January to 12 March 2003, 265 small cetaceans were stranded. Defra says: "Increased strandings are not necessarily an indicator of increased bycatch.
- 1998 - 369
- 1999 - 386
- 2000 - 421
- 2001 - 549
- 2002 - 649
"Strong tides and other natural phenomena have their part to play, washing bodies ashore where they might previously have remained at sea."
Trapped and drowned: The fate of too many cetaceans
Most strandings of dolphins and porpoises occur in the western part of the English Channel.
Mr Morley said: "The bycatch problem poses a major threat to the conservation of dolphins and other cetaceans.
"But the problem cannot be solved in isolation. Co-operation at European Union level is vital if there is to be real progress."
His recommendations include a legal requirement for some UK vessels in the Celtic and North Seas to use pingers, and an effective observer scheme to monitor cetacean bycatch.
There will also be better cetacean population monitoring, and a recognised accreditation scheme for cetacean-friendly fisheries.
Andy Smerdon, of Aquatec, the firm which makes the pingers, said: "They're designed to warn the animals, not to scare them.
"The pingers emit less noise than most mobile phones - but presumably for the cetaceans they're just as annoying."
An Aquamark pinger: Like "an underwater mobile 'phone" (Image: Aquatec Subsea Ltd)
The devices emit random signals, at intervals ranging from five to 30 seconds, and most are in the ultrasonic range, beyond human hearing.
The Sea Mammal Research Unit (SMRU) at the University of St Andrew's is experimenting for Defra with a net with a separator trawl, a panel that allows cetaceans and sharks to escape.
If it proved effective, Mr Morley said, he would want to see it adopted by all UK and EU boats.
He praised Denmark and Ireland for their support for introducing pingers, but thought most other member states were dragging their feet.
He said: "I feel it's time for other fishing countries to pull their weight on this.
"I'm frustrated we've had to put so much effort into it without many others supporting us."