Much of the material that washes up on the beaches of southern England is natural, but certainly not all of it. © River Ocean Foundation.

Matt Gaw strapped on his flippers and headed for the Booth Museum to discover the secrets of the Sussex shoreline.

Dr Gerald Legg of Brighton’s Booth Museum of Natural History is in a state of some excitement. A porpoise has been stranded on Hove beach and there’s a chance it could be coming to his museum.

Being washed up on a wind-swept, shingle beach may be a sad full stop for the porpoise, but it’s just the start of the story being told at the Booth Museum until March 19 2006.

Strandline – Secrets of the Sea, put together by Brighton-based charitable River Ocean Foundation and the Booth, investigates natural objects found on Sussex beaches, together with some less salubrious, man-made items.

As Dr Legg explains, the exhibition is about “understanding the beach as an ecosystem, not just as a place of entertainment.”

A recreated beach scene shows examples of the sort of stuff that washes up on our shores. © River Ocean Foundation.

The River Ocean Foundation, which has worked on similar projects with the Booth Museum before, is dedicated to increasing awareness of and encouraging care for our aquatic environment through education.

A large cross-section of the shoreline demonstrates to visitors how flotsam and jetsam are deposited by every tide.

A collection of corroded, man-made objects are labelled with the number of years they take to decompose: a sad-looking flip-flop takes 50 years while a disposable nappy could navigate the seven seas for 500 years.

It is immediately apparent that the inanimate artefacts – whether a bottle, bin-bag, whale or winkle – all have hidden depths. A mass of stories lurks among the seaweed; tales of predators, parasites, pollution and even folklore and history.

A Harvest Moon above the sea. © River Ocean Foundation.

Medieval naturalists saw mythical creatures in dog-fish eggs, still called “mermaid’s purses” today, and gigantic narwhal horns were taken as tangible proof of unicorns. Dr Legg reticently admits that a fish hatchery would have been a perfect addition to the exhibition, but logistically impossible.

One of the more unusual displays features a ‘genuine’ mermaid. The mermaid or more accurately, merman (I’m reliably informed that a mermaid has more than two nipples) is a grisly testament to Victorian collectors who brought the part-fish, part-monkey specimen back from South East Asia.

There is something of the macabre about the Booth museum. The giant bones of a large fin whale, who shared the same fate as the Hove porpoise, and pots of pickled squid (some going back to Challenger’s Victorian voyage) fascinate children and clearly add to the exhibition’s educational pull.

As one mother commented: “The kids love anything that’s remotely gory.”

The message does seem to be hitting home. On the Booth message board, written in a child’s hand is the simple demand: “Educate the naughty people.” Consider yourself told.