Aspects of Behavior
241
these fish are the caranxes (Selar), sea perches (some of Lutjanidae), and
atherinids (Pranesus).
Many of the daytime herbivorous, corallovorous and benthovorous fish
migrate diurnally between different reef biotopes, e.g., between the biotope
where they forage and the biotopes where they relax - the same as people
diurnally move between home and work-place. Among these fish could be
mentioned the scariids, acanthurids (Acanthurus, Ziebrasoma) , chaetodontids, some pomacentrids, mugilids, mullids, and some of the labrids
(Hobson 1972, 1973; Buckman and Ogden 1973; Ogden and Zieman 1977;
Rublee and Zeeman 1984). These fish emerge from their night hiding places
at dawn and accumulate within schools, which then start to move to their
foraging places - to the thickets of macrophytes and ramose corals or to the
lagoon. In the evening they return to their same nocturnal refuges (Starck
and Shroeder 1985; Fig. 6.4).
The migratory schools most often are monospecific, but some fish migrate
within schools containing several species. These are, for examples, the
migratory schools of the Caribbean parrot fish Scarus croicensus. This fish,
as many other scarids, spends the night "sleeping" in a mucous cocoon
hidden in crevices and holes of reef slopes (Ogden and Buckman 1973). At
dawn they come out from their refuges and form large schools. Often their
school is joined by fish from other species: groupers, sturgeons. The schools
move to the flat or to shallows covered with seeweeds or with grass for
foraging. Thus they pass sometimes up to several kilometers following a
complex but permanent route. The routes of schools are selected by
migrating fish observing the position of "c1eanear stations", where on the
way to underwater meadows the fish can devoid themselves of parasites on
their skin and gills. The sanitary work is done by fish cleaners Labroides
dimidiatus and Gobiosoma sp. The formation of schools for the diurnal
foraging migrations is an important behavioral adaptation of reef fish. It
helps them not only to escape predators, but also to find the routes of
migrations because the schools include old experienced specimens which
know them and lead the shoal. Thus the information about the best routes
and best foraging places is accumulated and preserved within a given local
fish population. It seems that the migrating schools during their move wake
use of the topographic features of the bottom landscape for navigation
(Hobson 1973). Migrating fish transfer nutrients from foraging places
(seagress beds) to places of relaxation (coral thickets), thus playing an
important role in trophic interrelations between reef biotopes (Meyer et al.
1983).
The exact times of the morning and evening migrations in populations of
different species are strictly kept apart to avoid disordered swarms, which
are so convenient for hunting predators (Domm and Domm 1973). Some
nocturnal fish even change coloration during their shift from daytime
relaxation to nocturnal activity (Starck and Schroeder 1965). Thus some
nocturnal sea perches (fam. Lutjanidae) and grunters (fam. Haemulidae),
241
these fish are the caranxes (Selar), sea perches (some of Lutjanidae), and
atherinids (Pranesus).
Many of the daytime herbivorous, corallovorous and benthovorous fish
migrate diurnally between different reef biotopes, e.g., between the biotope
where they forage and the biotopes where they relax - the same as people
diurnally move between home and work-place. Among these fish could be
mentioned the scariids, acanthurids (Acanthurus, Ziebrasoma) , chaetodontids, some pomacentrids, mugilids, mullids, and some of the labrids
(Hobson 1972, 1973; Buckman and Ogden 1973; Ogden and Zieman 1977;
Rublee and Zeeman 1984). These fish emerge from their night hiding places
at dawn and accumulate within schools, which then start to move to their
foraging places - to the thickets of macrophytes and ramose corals or to the
lagoon. In the evening they return to their same nocturnal refuges (Starck
and Shroeder 1985; Fig. 6.4).
The migratory schools most often are monospecific, but some fish migrate
within schools containing several species. These are, for examples, the
migratory schools of the Caribbean parrot fish Scarus croicensus. This fish,
as many other scarids, spends the night "sleeping" in a mucous cocoon
hidden in crevices and holes of reef slopes (Ogden and Buckman 1973). At
dawn they come out from their refuges and form large schools. Often their
school is joined by fish from other species: groupers, sturgeons. The schools
move to the flat or to shallows covered with seeweeds or with grass for
foraging. Thus they pass sometimes up to several kilometers following a
complex but permanent route. The routes of schools are selected by
migrating fish observing the position of "c1eanear stations", where on the
way to underwater meadows the fish can devoid themselves of parasites on
their skin and gills. The sanitary work is done by fish cleaners Labroides
dimidiatus and Gobiosoma sp. The formation of schools for the diurnal
foraging migrations is an important behavioral adaptation of reef fish. It
helps them not only to escape predators, but also to find the routes of
migrations because the schools include old experienced specimens which
know them and lead the shoal. Thus the information about the best routes
and best foraging places is accumulated and preserved within a given local
fish population. It seems that the migrating schools during their move wake
use of the topographic features of the bottom landscape for navigation
(Hobson 1973). Migrating fish transfer nutrients from foraging places
(seagress beds) to places of relaxation (coral thickets), thus playing an
important role in trophic interrelations between reef biotopes (Meyer et al.
1983).
The exact times of the morning and evening migrations in populations of
different species are strictly kept apart to avoid disordered swarms, which
are so convenient for hunting predators (Domm and Domm 1973). Some
nocturnal fish even change coloration during their shift from daytime
relaxation to nocturnal activity (Starck and Schroeder 1965). Thus some
nocturnal sea perches (fam. Lutjanidae) and grunters (fam. Haemulidae),