Biology of the Sanzos' goby, Lesueurigobius sanzoi (de Buen, 1918), off Cabo Raso, Portugal.

Abstract

The presence of Sanzo's goby, Lesueurigobius sanzoi (de Buen, 1918), off Cabo Raso, Portugal, is recorded for the first time. The biology of this population was studied based on 11 samples collected between April 2000 and September 2001, at depths of 70-100 m, on muddy and sandy bottoms. The females reach a standard length of 110 mm and males 103 mm. It attains an age of 24 months, which equals two breeding seasons. The otoliths form two translucent rings each year, which corresponds to the winter growth and the reproduction period. Sanzo's gobies can be classified as "premature" and "standard" individuals, whether if the first breeding occurs before or after the first winter, respectively. "Standard" individuals, who have an extended first growth, reach longer length than "premature" individuals, which first growth is much shorter. Although discrete, sexual dimorphism was noticeable even outside the spawning season. Breeding season occurs between May and September/October with more than one spawning. The minimum length for which the maturity stage occur was 64 mm, at an age of 0+. The feeding activity rhythm is quite constant throughout the year, and predominantly consists of small crustacea and molluscs, although polychaets also features commonly in its diet.