242
Coral Reef Fish
change their bluish or yellow coloration ("sleeping gowns") to silvery white
with black spots. The cardinals (fam. Apogonidae), relaxing within small
shoals under steep rocks of the reef edge, are bright-red, but on going to
hunt at night they change their color to palish-pink. The bright coloration of
these nocturnal fish in the daytime has the same adaptative importance as
the permanently bright, remarkable coloration of daytime migrating fish,
like parrot fish or sturgeons.
Many species of reef fish form monospecific or interspecific permanent
territorial groups. The numbers of these groups reveal a complex social
behavior. The same is true of the symbiotic or commensal groups of fish.
These types of social behavior are peculiar mostly to species of real reef fish
like pomacentrids, chaetodontids, gobiids, sturgeons, and parrot fish. The
features of territorial and social behavior in these fish, just as in terrestrial
animals, are actually genetically fixed ecological adaptations. They help
these fish to cope with the task of defending their breeding and feeding
areas from intruders and competitors. The relationships of symbiotic and
commensal species with their hosts help both partners to survive. Special
experiments have shown that the members of social groups know each other
"by face" (Ehrlich et al. 1977), as also members of monogamic couples of
fish easily recognize their mates among similar equally colored specimens
(Reese 1975). Territorial fish perfectly know the landscape and the borders
of their territories. To defend them, they drive out from their plots first of
all their direct food competitors, perfectly recognizing them (Mahoney
1981). This kind of interspecific antagonism is also part of the complex
system of social behavior in reef fish (Buckman and Ogden 1973; Sale 1980).
It is well developed in territorial fish, like the sergeant fish (fam.
Pomacentridae) and in sturgeons. The abundance of fish that demonstrates a
settled mode of life and territorial behavior is one of most remarkable
feature of reef-fish communities (Colette and Talbot 1972; Sale 1980).
Among the most common kinds of territorial behavior of reef fish the
following can be mentioned: (1) defense of the territory around their holes
(lizard fish, moray eels); (2) collective guarding by the permanent groups of
pomacentrids of their territories only from the intrusion of their competitors
the herbivorous fish Pomacentrus flavicanuda, Eupomacentrus
dorsopunctatus (Mahoney 1981); (3) collective defense of private "pasture"
by a group of owners - pomacentrids Pomacentrus jenkinsi - attacking and
repelling all intruding fish including strangers of the same species, whom
they recognize "by face"; (4) permanent occupation by monogamic fish
couples or by small polygamic parties of extensive bottom space, which
serves as pasture and as breeding territory, and which they guard only from
intrusions of other males or other couples, especially during the spawning
period (sturgeons, chaerodontids, wrasses); (5) permanent living of a single
fish, of a couple or of a small group near some element of reef construction
which serves as a refuge, without their attempting to defend the place from
other fish (pomacentrids Dascyllus arguanus, Cromis sp., some morays,
many serranids, sturgeons and chaetodontids).
Coral Reef Fish
change their bluish or yellow coloration ("sleeping gowns") to silvery white
with black spots. The cardinals (fam. Apogonidae), relaxing within small
shoals under steep rocks of the reef edge, are bright-red, but on going to
hunt at night they change their color to palish-pink. The bright coloration of
these nocturnal fish in the daytime has the same adaptative importance as
the permanently bright, remarkable coloration of daytime migrating fish,
like parrot fish or sturgeons.
Many species of reef fish form monospecific or interspecific permanent
territorial groups. The numbers of these groups reveal a complex social
behavior. The same is true of the symbiotic or commensal groups of fish.
These types of social behavior are peculiar mostly to species of real reef fish
like pomacentrids, chaetodontids, gobiids, sturgeons, and parrot fish. The
features of territorial and social behavior in these fish, just as in terrestrial
animals, are actually genetically fixed ecological adaptations. They help
these fish to cope with the task of defending their breeding and feeding
areas from intruders and competitors. The relationships of symbiotic and
commensal species with their hosts help both partners to survive. Special
experiments have shown that the members of social groups know each other
"by face" (Ehrlich et al. 1977), as also members of monogamic couples of
fish easily recognize their mates among similar equally colored specimens
(Reese 1975). Territorial fish perfectly know the landscape and the borders
of their territories. To defend them, they drive out from their plots first of
all their direct food competitors, perfectly recognizing them (Mahoney
1981). This kind of interspecific antagonism is also part of the complex
system of social behavior in reef fish (Buckman and Ogden 1973; Sale 1980).
It is well developed in territorial fish, like the sergeant fish (fam.
Pomacentridae) and in sturgeons. The abundance of fish that demonstrates a
settled mode of life and territorial behavior is one of most remarkable
feature of reef-fish communities (Colette and Talbot 1972; Sale 1980).
Among the most common kinds of territorial behavior of reef fish the
following can be mentioned: (1) defense of the territory around their holes
(lizard fish, moray eels); (2) collective guarding by the permanent groups of
pomacentrids of their territories only from the intrusion of their competitors
the herbivorous fish Pomacentrus flavicanuda, Eupomacentrus
dorsopunctatus (Mahoney 1981); (3) collective defense of private "pasture"
by a group of owners - pomacentrids Pomacentrus jenkinsi - attacking and
repelling all intruding fish including strangers of the same species, whom
they recognize "by face"; (4) permanent occupation by monogamic fish
couples or by small polygamic parties of extensive bottom space, which
serves as pasture and as breeding territory, and which they guard only from
intrusions of other males or other couples, especially during the spawning
period (sturgeons, chaerodontids, wrasses); (5) permanent living of a single
fish, of a couple or of a small group near some element of reef construction
which serves as a refuge, without their attempting to defend the place from
other fish (pomacentrids Dascyllus arguanus, Cromis sp., some morays,
many serranids, sturgeons and chaetodontids).