This is peak elver fishing season on the River Severn but there are worries about illegal poaching and smuggling of these baby eels to the Far East.
So I spent a night out on the banks of the river to see how the problem is being tackled.
Elvers are amazing creatures. Small, transparent worm-like fish that arrive in the Severn from the Sargasso Sea in their millions. They work their way upstream and after five to 20 years living in the Severn they head back out to sea to breed.
Right now, it's full moon which means big tides and a huge bore, a surge wave, coming up the Severn at night.
The elvers are carried along and also swim with the bore, and at weirs and other obstacles they are lifted over the obstruction into the next part of the river.
There's something spooky about standing late at night by the river Severn and hearing the familiar noise of water rushing over a weir..., and then hearing the weir go silent as the bore arrives and lifts the river level above it.
Right now all along the river you'll find hundreds of elvermen fishing for elvers.
Believe it or not elvers are a delicacy, although not generally considered so in this country.
In Spain and elsewhere in Europe people enjoy them as tapas and tasty nibbles so each kilo the elvermen catch currently fetches £150. While we were out we heard tales of people catching 18kg of elvers in an evening which would earn them several thousands pounds.
Elvers are also considered a delicacy in the Far East. But since eels and elvers are endangered and because the demand from countries like China is so huge, export outside Europe has now been banned.
Of course where there's a ban and huge demand there's also money and smuggling. A kilo of elvers in China could cost £6,000. That's more than Beluga caviar.
For the first time in this country a large scale elver smuggling operation has been caught and stopped. At Heathrow a man was found trying to smuggle 200kg of elvers which would have a street value in his attempted destination of Hong Kong of £1.3m
In the wake of this teams from the Environment Agency have been stepping up their patrols and intelligence gathering with the help of law abiding elvermen along the Severn.
Because 60% of all the elvers caught on the Severn are not eaten, they actually go to help restock other areas in Europe where the population of eels has declined even further than here. And if the elvers we do have end up being smuggled to the Far East that will be bad news for the elvermen of the Severn and the eels themselves.