Revista Chilena de Historia Natural 75 (1): 189-200, 2002
RESEARCH ARTICLE
Abundance, distribution and feeding patterns of a temperate reef fish in subtidal environments
of the Chilean coast: the importance of understory algal turf
Cheilodactylus variegatus is an abundant carnivorous demersal reef fish that
lives in the shallow subtidal of the north-central Chilean coast. Characteristically, these environments are dominated by kelp forests of
Lessonia trabeculata. This species preys on a great variety of benthic invertebrates, and shows particularly high
consumption rates on amphipod crustaceans. In our study, two widely separated populations of C. variegatus were
considered (central and northern Chile). Individuals that form part of these populations show considerable differences in their
distribution, abundance and trophic behavior. In the northern zone, the species is abundant and both juveniles and adults are distributed
along the whole bathymetric gradient. This contrasts with populations found in central Chile, which are more sparse and lack juveniles.
The distribution and abundance patterns appear to be influenced mainly by the great abundance of diverse understory macroalgae in
the northern subtidal, which harbors a large number of invertebrates, especially amphipods. In contrast, the understory algal
abundance of the central zone is much lower, and does not show a direct relationship with the lesser abundance of amphipods. In
general, C. variegatus maintains a high consumption rate on amphipods throughout its ontogeny but it includes several
other prey items in later ontogenetic stages. The different understory algal assemblages, and their associated fauna, are likely to be the
main factors influencing the patterns of abundance and distribution observed between these two geographically distinct fish
populations.
Key words:
Cheilodactylidae,
shallow subtidal, understory macroalgae, carnivorous fish, amphipods, distribution, abundance, Chile.
