Abundance, age-structure and growth and reproduction of gobies (Pisces, Gobiidae) in the Ria de Aveiro Lagoon (Portugal)

Abstract

Biological data concerning the abundance, age, growth and reproduction of seven species of gobies in the Ria de Aveiro lagoon (Portugal) are presented and discussed. The seasonal changes in species abundance are ascribed either to recruitment and mortality or to sporadic occurrence. Gobius niger, Pomatoschistus minutus and P. microps are included in the first case, and P. pictus, P. lozanoi, Aphia minuta and G. paganellus in the second. Only G. niger and G. paganellus were found to live more than 1 year. Growth took place all year round, although it was slow in winter. There is an indication that temperature influenced the start of growth in spring. Almost all the species (except G. paganellus and P. lozanoi) were found to spawn inside the lagoon. Spawning seasons were found to be shorter for G. niger and A. minuta (summer only) than for species of Pomatoschistus (with reproductive periods in winter and summer).