ASFB Home > The effects of spatial and temporal factors on the abundance of seven key finfish species along south-western Australia.

Habitat Differences in the Presence of Late Stage Larvae in a Rocky Fish Community: Implications for Conservation

Ricardo Beldade, Rita Borges and Emanuel Gonçalves

Ispa, LISBOA, PORTUGAL

THEME: ASFB (Poster)

It is often assumed that recruitment is independent of local reproduction, however the retention of fish larvae close to shore has recently been documented. One of the advantages that might derive from larval retention nearshore is the ability to find a suitable habitat to settle at the end of the larval stage. There is some evidence which suggests that active retention near the adult’s habitats may occur from hatching and not only at settlement. We used a plankton net attached to an underwater scooter to sample five different habitats (bays, rocky blocks, sand/rock interface, vertical rocky intertidal and bedrock) present in the study area (Marine Park of the Arrábida Nature Park, Portugal). For each habitat, 24 samples were collected with five minute trawls from 15 June to 15 August 2001. Densities of larvae in the above habitats revealed significant differences between the bays and the rocky blocks, sand/rock and bedrock. The intertidal is only significantly different from the bedrock habitat. The most abundant families were Gobiidae, Labridae and Tripterygiidae. Gobiidae were the most abundant group in all habitats, ranging from 86% in the sand/rock interface to 28% in bays, except in the intertidal where they were replaced by Tripterygiidae. Differences between habitats in abundance and composition of the fish larvae community are important clues to their role as growth and nursery grounds and suggest different levels of importance from a conservation point of view.