Coffin Bay is a great spot for shellfish,thanks in part to the influence of two cleansing tides that keep the molluscs sweet and plump. On the shoreline (and at the entrance to the park) sits the eponymous fishing town - home to 600 people including several millionaire oyster farmers.

When we resume pedalling,Lunch leads the way to sheltered coves,where he dispenses masks and snorkels. Before long our bags and buckets are filled with cockles,aubergine-coloured scallops and glossy black mussels."That'll do for first course. Do you like salmon?"Lunch says.

The fishing beach is reached after a short drive followed by some serious off-roading in which we negotiate a plain of sand dunes so wide and high that you can see neither the rolling fields of wheat behind,nor the Great Australian Bight in front.

The beach,too,is enormous,running for kilometres on either side of us and free of any other human beings. A wave rears up and I see schools of salmon running across the green face;we cast our spinners on long rods and haul in the first fish in a matter of minutes.

For the oysters,however,we'll need water craft. We head back to town and join skipper Darian"Dazza"Gale and half a dozen guests aboard the Coffin Bay Explorer.

The famous bay is bigger than I expect and it takes some 30 minutes to reach one of the many oyster leases. Black racks stand stark against the glassy water while the sunlight strikes a million mirror-glints;Dazza unhooks a barnacle-clad basket,emptying oysters noisily on the deck.

"Low in cholesterol,low in calories and the highest natural form of zinc ..."he says. The skipper shucks and shares,and in between guzzling,I ask him about the emus and kangaroos of Black Springs Beach.

"Yep,I've seen it - under the water. Back before 1972 - before it was a national park - the locals used to see cattle doing the same thing. Cattle can smell fresh water from up to a mile away. I reckon the native animals must have learnt it from them."

Dazza has natural surprises of his own. We circle an isle of rocky pinnacles called The Brothers. It's a relic of Gondwanaland,comprising petrified tree roots,and has the acrid smell of bird droppings left by noisy populations of cormorants and Antarctic skuas. We watch sleeping New Zealand fur seals lying among the rocks - until a small brown head emerges a metre from our bow.

"It's an Australian sea lion,"Dazza says."These blokes will play for hours."The sea lion loops back and forth,watching us with its big eyes. I begin to think these waters have it all,then Dazza asks:"Have you ever seen a sleeping dolphin?"

He motors to a different part of the bay,cutting the engine close to a pod of some 30 bottlenose dolphins. They don't seem bothered by our approach,turning gently in the water. Dazza points to where a few dolphins lie still.

"They're asleep,"he says."They shut down half of their brain for three or four seconds. Then they'll swap,and shut the other half down. For a long time,no one had been able to see wild dolphins asleep. I had a group of international marine scientists with me;they didn't believe it until I showed them."

As a finale,the skipper guns his engines to create a wake. The dolphins are immediately stirred into life,jumping on the surf to indulge in some acrobatics.

That evening,as the sun slips into the sea,Lunch and I eat our harvest on the deck of our Coffin Bay beach house (a great spot for a beer). He sticks to his mantra of keeping seafood"simple and fresh":the oysters are au naturel,the scallops are barely shown the flames,the salmon barbecued in foil. The cockles and mussels are served in a linguine with oil,lemon and cracked pepper.

But Lunch has one more surprise.

"I've got a secret spot where I get green-lip abalone,"he says."This is my signature dish."

Vindaloo abalone not only sounds awful,it seems sacrilege to spice up a shellfish that sells for $150 a kilogram. But it's one of the most intense,flavoursome and rewarding dishes I've had."God that was good,"I gasp.

"It ought to be,"Lunch laughs,"we've just eaten about $300 worth of ab."

Before arriving in Coffin Bay,I'd had vindaloo abalone as often as I'd seen kangaroos with their heads underwater. Both need to be shared with an unsuspecting world.

Max Anderson was a guest of Goin'Off Safaris.

FAST FACTS

Getting there Qantas (qantas.com.au) flies from Sydney to Port Lincoln via Adelaide and one-way fares start from $217. One-way flights from Melbourne start from $212.

Touring there Dave Doudle can tailor a Goin'Off safari package for two to seven days. Two-day safaris cost from $850 a person including transfers from Port Lincoln,all ground transport,Coffin Bay Explorer cruise,fishing/foraging trips,two nights'accommodation in a waterfront beach house and all meals. The itinerary is flexible and can also include Eyre attractions such as Port Lincoln tuna swim,swimming with sea lions and shark-cage diving (costs apply).

Contact Goin'Off Safaris,0428 877 488;seegoinoffsafaris.com.au.