In this paper we report for the first time the occurrence of Parablennius sanguinolentus in mainland Portuguese waters. Since this species is common in the Mediterranean and in the Bay of Biscay, there appears to be a distributional gap along the Portuguese coast. The present finding, together with recent data on the occurrence of several other blenniids in the Atlantic coast of the Iberian Peninsula, formerly supposed to be Mediterranean endemics, stresses the urgent need for detailed zoogeographical investigations on the inshore fish fauna of south-west Europe.
Parablennius sanguinolentus (Pallas, 1811) is widespread in the Mediterranean (Zander, 1986). On the Atlantic coast of Europe, however, it was known only from the Bay of Biscay where it is abundant in some places (Motos & Ibañez, 1979), from the north-west coast of Spain (Devesa et al., 1979) and recently from the Atlantic coast of Andalucía (Spain) (Rubio, 1991). It is also very common in the Azores, Madeira and Canary Islands if one assumes that P. parvicornis (Valenciennes, 1836) belongs to the same species, but this is as yet an unresolved issue (Zander, 1979; Almeida & Harmelin-Vivien, 1983; Bath, 1990; Santos, 1992). Although Zander (1986) presented a distributional map that includes the mainland Portuguese coast, no report on the occurrence of this species was known for this area. In a survey of the literature on the blennioid fishes occurring in Portuguese waters, we could not find a single citation that could possibly be ascribed to P. sanguinolentus for mainland Portugal (Oliveira et al., 1992).