As the spring days lengthen into summer and southern Europe warms, early holidaymakers are beginning to make their way to the Algarve, sunning themselves on the sandy beaches and filling up the cafés.
But the terrain at the eastern end of Portugal's south coast is more suited to wildlife than to human visitors. Along the shore between Tavira and Faro, sandy scrubland and marshy salt flats provide a habitat for a rich variety of birds, animals and wild flowers. This is the Ria Formosa, a 50km expanse of coastal parkland established to preserve the natural environment and protect its delicate ecosystems. The park occupies the area between the Algarve railway and the Atlantic Ocean, and is signposted off the main coastal highway.
The best way to explore the Ria Formosa is to start at the visitor centre and follow the waymarked trail, a peaceful track through pine woods and olive groves that never meanders far from the water. Storks nest on distant telegraph poles, while fiddler crabs can be spotted sidling in and out of mud holes. About halfway along the path, though, the sound of distant birdsong is drowned out by the barking of a colony of dogs.
These are the Portuguese water dogs for which this part of the Algarve is now enjoying some global recognition. With their curly black coats, they resemble overgrown and overly enthusiastic poodles as they jump up to greet any visitor who heads in their direction. But these are no ordinary hounds: one of their breed, named Bo, this week took up residence in the White House as First Dog. A glance down at their paws reveals another important difference between them and the average domestic pet: these dogs have webbed feet. They acquired their name – and the membrane between their toes – from the role that they carried out on the Algarve coast for centuries, guiding fishing boats towards their catch. Diving from the boats and swimming underwater when necessary, the dogs would sniff out the shoals of sardines or tuna, bark to alert the crew, then head into the water to round up the fish and steer them into funnel-shaped nets.
While most dogs navigate through the waves using doggie paddle, these working animals use their distinctive paws to swim more like humans. Traditionally, a dog was part of the crew, working alongside the fishermen and paid for its work – although in the case of the dogs, payment was in fish rather than cash. Canine coats were trimmed into a lion cut, thick and shaggy at the front so that the animals didn't feel the cold when they jumped into the water; short at the back so they could swim faster and dive deeper.
The main fishing grounds are out to sea, beyond the line of sandspits and islands which protect the mainland from the Atlantic Ocean with a barrier of dunes forged by centuries of wind and tidal currents. Boats from Olhao, the town nearest to the entrance to Ria Formosa, take passengers to the islands of Armona and Culatra, whose sandy beaches and waterside cafés are popular with visitors; and to Farol, where a cluster of attractive fishermen's cottages nestle around the base of a lighthouse.
More modern methods of fishing were introduced in the 1950s, and when traditional fishing nets were finally abandoned in 1972, the water dogs were no longer needed. The breed came dangerously close to extinction until a colony was established in the Ria Formosa park. It is now one of the most fascinating attractions on the entire coast. Like the old tuna boat lying by the water's edge at the far end of the park, these dogs are a reminder of the traditional way of life which once existed along the Algarve.
There are other memorials to bygone times in the park, too. Near the kennels is a waterwheel, designed by the Moors who once occupied this part of Portugal. Donkeys and mules plodded monotonously around a circular path, attached to a system of wheels and pulleys that irrigated orchards full of apricots, plums and citrus fruits.
A little further along the coast is a tide mill, one of nearly 40 that once existed in Ria Formosa. Built in the 13th century to harness energy from the tide to grind cereals, it was used almost continuously until the 1950s; by then, mechanisation had made this practice obsolete, too.
Fishing remains the most important industry in Ria Formosa. There are an astonishing 1,600 shellfish farms on the tidal flats, their boundaries visible at low tide like maritime allotments. Seven thousand tons of clams and oysters are harvested each year, while visitors pick up cockles and razor clams that are half-submerged in the sand. Dogs have no role to play in the modern fishing industry, but the small colony in the park continues to prove popular with those visiting. And now that there is a Portuguese water dog in the White House, perhaps one day the Obama family will be among the visitors.
Ria Formosa park (00 351 289 700 210; icnb.pt) is on the outskirts of Olhao. It opens 9am-12.30pm and 2-5.30pm Monday to Friday; admission costs €2.50 . The water dogs come out of their kennels 11am-1pm and 2-4pm Monday to Friday.