Sometimes Paul Gilson manages to catch a few fish.

This may not appear to be a world-shattering statement, since Paul is one of Southend's best known professional fishermen, as well as a long serving member of the Southend lifeboat crew.

Yet listen to the tales of the weird and wonderful items that Paul has dredged up in his nets and you can only marvel that a few sprats also found room to hitch a ride.

Much of this haul the part without gills has found its way to a grateful Southend Museum. Down the years Paul has acted as a sort of unofficial marine archaeologist to the institution and it was here, surrounded by his catch, that Paul talked to members of the Southend Pier Museum Foundation.

To Paul, the Thames Estuary is a place of ever-changing wonders, both animal and mineral. No one knows from one day to the next what treasures, or occasional horrors, will be thrown up. This world of mud and water can hide an object for centuries, then suddenly release it on a whim.

"You steam past a particular sandbank for years and it always looks the same," he said. "Then suddenly one day you find it's shifted and you see a line of posts, and you've discovered a wreck."

Over many years, Paul has learnt to recognise the signs a tug on the nets, a loss of steerage. It could be just a pile of mud - "We catch a lot of mud," Paul said but equally it could be another release, courtesy of Davy Jones.

The Gilson family trawl includes a complete Volkswagen beetle, a Merlin aircraft engine in good enough condition to be reused, half a grand piano, a budgerigar that flew into the wheelhouse, a Gurkha khukuri knife, a set of drumsticks, a supermarket trolley, a Victorian half-length boot (minus the Victorian owner), and a 50-foot long tablecloth from a P&O liner.

Large or small, there is no hiding place for these objects once they've been hauled into the Gilson boat. The practiced fisherman's fingers will always pick out something novel.

"We work our way very carefully through the catch," Paul explained. "Some of it is very good at hiding, A Dover sole can roll itself up into a very tight ball. You don't want to miss it. It's worth a quid, more on the London market."

The delicacy of this fingertip operation may surprise those who think of fishing as all heave and haul. It's not unlike the way an archaeologist works, sifting slowly through a patch of earth, and it yields results in the same way. "You soon notice anything unusual, and if something radiates the fact that it's a bit different, I want to know what it is," Paul said.

Of course, even when the object is clearly identified, there always remains an element of mystery. "How did they get out there," Paul mused. "Who went to all that effort to dump them in the middle of the Estuary, and why?"

Who, for instance, dropped a bottle of premium quality champagne into the middle of the Medway Channel? After dredging up the bottle, Paul took it to a friend he describes as "champagne mad he'd bathe in the stuff if he could."

The wine inside still packed some fizz and was pronounced quite drinkable.

By an extraordinary coincidence, it was Paul who dredged up a bottle marked Gilson's Bloater Paste, and made by Gilson of New Bond Street.

The jar turned out to be something of a fishy business in more ways than one. "We couldn't trace anything about Gilson's paste in the family history," Paul said.

Unlike other fishermen, Paul has been less successful in terms of catching gold bullion bars or Rolex watches. Yet the water did present him with an even rarer treasure, a piece of pure amber. These were made up as necklaces for Paul's wife, Heather, and two daughters. "And when we get grandchildren, there's some left over for them as well," he added.

Paul Gilson is a fisherman to his marrow, who lies awake at night because he is so excited at the thought of going to work the next day. And, being a fisherman, he naturally enjoyed regaling his audience with the story of the treasure that got away.

"It's lying there on the deck," he recalled. "We approach it, then wham, a big fish drops out of the net and smashes it to bits."

Crockery of one sort or another forms the bulk of the history lesson netted by Paul. Some of this earthenware, notably the late 16th century Bellarmine bottles often used for charms and witches' spells, can be both decorative and valuable. Paul, though, prefers to hand it on to the museum.

"They know how to look after these things, and it's a pleasure to see them giving people pleasure," he says.

The size and range of the yield is in its own way a testimony to successful environmental policy in the Thames Estuary. "The sort of fishing that we do is very gentle," Paul said. "It's not like the much more disruptive fishing that's done in other parts of Europe. It means that the seabed isn't damaged, and it will go on protecting objects like these for hundreds of years."

The objects that Paul Gilson raised from the deep may have belonged to dead people, they may even from time to time be dead people, yet as far as he is concerned, they are all part of the mystery and wonder of the sea.

"People say the Thames Estuary is dying, but they simply don't look at it," Paul said. "The water is boiling with life and things to be discovered. You don't know what's out there until you start looking for it. We know more about the surface of the moon than we do about the sea off our shores."