Laguna de Potosí

Laguna de Potosí is a coastal lagoon south of Zihuatanejo, in the municipality of Petatlán, held back from the Pacific by a sandbar. On its shore sits Barra de Potosí, a fishing village of fewer than 400 people with three main streets. The lagoon and its surroundings cover about 800 hectares, 454 of them mangrove of three kinds: red, black and buttonwood. In the rainy season the water rises, breaks through the bar and the lagoon joins the sea.

The birds are the big draw. A study by the Universidad Autónoma Metropolitana in Xochimilco recorded 212 species here: 82 water or sea birds, 23 endemics and 19 on Mexico's list of protected species at risk. The same research counted 188 butterfly species, 68 fish, 18 reptiles and 488 plants, and crocodiles live in the mangroves.

The way to see it is by boat or kayak, in the permitted areas only, with the village boatmen and operators, who also run fishing trips. Between the lagoon and the beach are enramadas, open palapa restaurants that fill up at weekends with families from Zihuatanejo and nearby inland towns. The food is fresh fish: pescado a la talla, Zihuatanejo-style fish tiritas, shrimp and seafood pozole, with shrimp, octopus, squid and fish in a dried-chile broth. A rocky headland rises off the lagoon mouth, and in winter boats go out to watch humpback whales.

On the open-sea beach the current can be strong and it is no place for beginner swimmers; in places the sand forms a channel towards the lagoon mouth.