248
Coral Reef Fish
like birds, making curious curling swims with spreaded fins in an open
place off the outer reef slope with a good visibility. Permanent monogamic
couples are known in some species of gobies, chaetodontids and damsels
(Reese 1975, 1981). Their "matrimonial" mode of life helps them in everyday life to defend their territory or to construct and to clean the common
hole. It greatly increases as well successful multiplication of these fish, which
have very rare specific populations. The harems are common in hermaphroditic reef fishes, as we have seen above.
The guarding of eggs is a usual mode of behavior of bottom reef fish,
which lay their eggs on the solid substrate. They guard the spawns until the
larvae get out (Johannes 1978b). Among these fish there are representatives
of the families Apogonidae, Blennidae, Pomacentridae, Gobiidae,
Tetraodontidae, Syngnathidae. The damsel fish Acanthochromis polycanthus
and Chromis dimidiatus guard also their hatched larvae until they grow up
(Robertson 1973). Some small bottom fish construct the nests or holes
where they guard their spawn and later the larvae (Hudson 1977; Thresher
and Moyer 1983).
Most reef fish, even the bottom-dwelling ones spawn in the water column
and produce pelagic eggs (Mc Farland and Ogden 1985). The strategy of
such spawning is destined to decrease the grazing losses in spawn and larvae.
These fish select places off the upper reef slope, where the currents are
directed to the reef, so that their spawn should be driven back to the reef
(Johannes 1978; Sale 1980, 1985). The pelagic larvae of reef fish live in the
water column of the lagoon and in the near coastal waters, feeding on
zooplankton (Leis 1981). To escape the daytime grazing many of them
migrate in the daytime to the bottom, as do the demersal plankters. The
length of the larval period takes in most species 1-3 months (in moray eels
up to 10 months), but in case of absence of an appropriate place for
recruitment it could be longer (Johannes 1978b; Goldman et al. 1983;
Williams et al. 1984). The recruitment of larvae has a seasonal character. Its
rate varies in different years (Talbot et al. 1978; Williams 1983; Schroeder
1985). This results in definite fluctuations of the composition of fish
communities on reefs (Sale et al. 1984). Nevertheless, as we have seen
before, during a long period of time they are surprisingly stable. One of the
factors providing this stability could be seen also in the grazing out of the
larvae of foreign fish species by the residing adult fish, which thus promotes
the recruitment of their own (Russel et al. 1974). After the shift from
pelagic life, the recruited young fish adapt themselves to the settled life in
the benthic biotope, entering local groups or shoals. An average life time of
reef fish was evaluated to be 4-5 years (Ross 1978).
Coral Reef Fish
like birds, making curious curling swims with spreaded fins in an open
place off the outer reef slope with a good visibility. Permanent monogamic
couples are known in some species of gobies, chaetodontids and damsels
(Reese 1975, 1981). Their "matrimonial" mode of life helps them in everyday life to defend their territory or to construct and to clean the common
hole. It greatly increases as well successful multiplication of these fish, which
have very rare specific populations. The harems are common in hermaphroditic reef fishes, as we have seen above.
The guarding of eggs is a usual mode of behavior of bottom reef fish,
which lay their eggs on the solid substrate. They guard the spawns until the
larvae get out (Johannes 1978b). Among these fish there are representatives
of the families Apogonidae, Blennidae, Pomacentridae, Gobiidae,
Tetraodontidae, Syngnathidae. The damsel fish Acanthochromis polycanthus
and Chromis dimidiatus guard also their hatched larvae until they grow up
(Robertson 1973). Some small bottom fish construct the nests or holes
where they guard their spawn and later the larvae (Hudson 1977; Thresher
and Moyer 1983).
Most reef fish, even the bottom-dwelling ones spawn in the water column
and produce pelagic eggs (Mc Farland and Ogden 1985). The strategy of
such spawning is destined to decrease the grazing losses in spawn and larvae.
These fish select places off the upper reef slope, where the currents are
directed to the reef, so that their spawn should be driven back to the reef
(Johannes 1978; Sale 1980, 1985). The pelagic larvae of reef fish live in the
water column of the lagoon and in the near coastal waters, feeding on
zooplankton (Leis 1981). To escape the daytime grazing many of them
migrate in the daytime to the bottom, as do the demersal plankters. The
length of the larval period takes in most species 1-3 months (in moray eels
up to 10 months), but in case of absence of an appropriate place for
recruitment it could be longer (Johannes 1978b; Goldman et al. 1983;
Williams et al. 1984). The recruitment of larvae has a seasonal character. Its
rate varies in different years (Talbot et al. 1978; Williams 1983; Schroeder
1985). This results in definite fluctuations of the composition of fish
communities on reefs (Sale et al. 1984). Nevertheless, as we have seen
before, during a long period of time they are surprisingly stable. One of the
factors providing this stability could be seen also in the grazing out of the
larvae of foreign fish species by the residing adult fish, which thus promotes
the recruitment of their own (Russel et al. 1974). After the shift from
pelagic life, the recruited young fish adapt themselves to the settled life in
the benthic biotope, entering local groups or shoals. An average life time of
reef fish was evaluated to be 4-5 years (Ross 1978).