FUEDING fish face a fight to the death with the unlucky loser sinking into oblivion.
A crustacean conquest threatens to wipe out the lobster-like English crayfish as it battles with its US-style big brother.
The traditional and placid English white-clawed variety is struggling to cope with the much larger and more aggressive American pincered predator.
In fact it is now involved in a scrap for survival.
But local people can do their bit to save our shellfish if they take part in an environmental survey being carried out on the River Lune.
On the Lune at least, the British battler seems to have turned from lobster to mobster in a turf war more fitting of the infamous near-namesake East End gangsters. Now it is outnumbering the stateside invader.
"The white-clawed crayfish cannot compete with the bigger signal crayfish," says Neil Guthrie, the man in charge of the survey.
"But the good news is that we are recording more sites on the River Lune where the species is becoming more prevalent.
"And we have only found a couple of areas containing the signal crayfish.
"That is good news because they carry a fungal infection called crayfish plague. That kills the white-clawed ones but the American one is somehow immune to the disease."
Environment Agency conservation officers want people to report any sightings of crayfish on the Lune to complete their survey.
Mr Guthrie says: "So far the survey has been positive for the 105 sites we have recorded.
"We have found five areas where the white-clawed crayfish is living and only two where there is the signal variety.
"If people can contact us with details of sightings we would appreciate it because it is important to try and maintain levels."
The signal crayfish was introduced to this country around 30 years ago. They were supposed to be kept in fish farms for use in the food industry but many escaped into the wild and, in several parts of the country, have completely wiped-out the native white-clawed variety.
Mr Guthrie adds: "They were brought in because they look better on a plate but a lot have found their way into the white-clawed habitat and started to out-breed."
Dr David Rogers, the lead partner of the national Biodiversity Action Plan, which supports the survey, says: "Crayfish are a tremendous species and we want to do as much as we can to stop them dying out.
"We don't want to kill off the signal crayfish but we do want to ensure the survival of the English one."
Anyone who has spotted crayfish on the Lune can call environment officers with their information on 01772-714025.
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