Coastal lagoons were sampled along the ~430 km coast of Santa Catarina State, South Brazil (Fig 2). This coastline can be divided into two major segments:—from the north border, in Itapoá, up to the Cape Santa Marta, at Laguna, the coast is N-S orientated, highly embayed with rocky headlands alternating with small bays;—southwards of Laguna, the straight NE-SW coast is dominated by high energy sandy shores. The most frequent swell wave direction along this coast is from the south, with average heights of 2.5 m; the coast has a micro-tidal regime with higher tides in the north (mean astronomic tide 1 m in Itapoá) than in the south (0.5 in Laguna); the general alongshore littoral drift is from S-SE to ENE-NE, but local reversals take place during strong NE conditions . Coastal lagoons are mainly concentrated in central/southern portions of the coast (Fig 2).