Feeding of Reef Fish
233
participate in the digestion of macrophytes by fish (Sutton and Clemens
1988).
The trophic guild of herbivorous fish embrace a wide spectrum of taxa. It
includes four complete important families of reef fish: Acanthuridae,
Scaridae, Siganidae and Kyphosidae. The most numerous are the species of
the first two which comprise even a significant part of the total ichthyomass.
Herbivorous fishes in which plant material as food source is dominating are
also present in many other families of reef fish, like the Pomacentridae,
Gobiidae, Chaetodontidae, Blennidae, and Balistidae. Mugilids and
acanthurids feed on microphytobenthos and on periphyton in which plant
material dominates. Numerous herbivorous and omnivorous fish feed also
on the feces of predatory fish, thus increasing the efficiency of energy
utilization in reef food webs (Robertson 1982) Some hemiramphids
(Hemramphus dussumeri, H. brasiliensis) feed on phytoplankton and on
flakes of macrophytes and seagrass leaves, collecting them from the surface
film. Among the omnivorous fishes in which plant material comprises a large
portion of food are the angel fish Pomacanthus arguatus and P. paru, the
puffer Canthigaster rostrata, and the balistids Monocanthus ciliatus and M.
chinensis (Randall 1967; Conachear et al. 1979; Polunin 1989).
Herbivorous fish are strictly specialized with respect to the kinds of plant
food they consume. In experiments with the scarid Sparisoma radians it was
found that the scale of preference for consumed plants approximated the
following: (1) seagrass Thalassia covered with epiphytes, (2) bare seagrass
Halodule, (3) bare seagrass Thalassia, (4) the grass Syringodium, (5) the
alga Dictyota, (6) the alga Enteromorpha, (7) the alga Caulerpa, (8) the alga
Halimeda, and (9) the alga Penicillus. The scale of preference depends on
the nutritional quality of a given plant species and on its relative toxicity for
a given fish. Among those most preferted by fish are the seagrass Thalassia,
the algae Enteromorpha, Ulva, and Codium (Randall 1961; Earle 1972;
Hobson 1974; Ogden and Lobel 1978; Lobel and Ogden 1981). The grazing
pressure induced in plants the evolutional acquisition of defence
adaptations. Among these is the adaptation of some plants to grow in
turbulent surf zones, where their grazing by fish is disturbed (coralline algae,
filamentous algae, seagrasses). The thalloms of many algae are heavily
loaded and armed with calcareous material. This decreases their food quality
for fish (Turbinaria, Penicilius, Halimeda). Other algae are overloaded with
tannin impeding their digestion by fish, or are soaked with toxins which
repel their grazing. Out of 48 species of algae, which inhabit tbe shelf off
some islands south of Japan, 38 have toxic substances in their thalloms
(Hashimoto and Fusetani 1972). The thalloms of Sargassum contain tannins,
the alga Asparagopsis ketones, Caulerpa the toxin caulerpin, Laurencia
chlorides, and Dictopteris the toxin dictyopterin. The toxicity of many bluegreen algae is well known.
The grazing activity of herbivorous fish is one of the most powerful
ecologial factors controlling the structure, recruitment processes and
233
participate in the digestion of macrophytes by fish (Sutton and Clemens
1988).
The trophic guild of herbivorous fish embrace a wide spectrum of taxa. It
includes four complete important families of reef fish: Acanthuridae,
Scaridae, Siganidae and Kyphosidae. The most numerous are the species of
the first two which comprise even a significant part of the total ichthyomass.
Herbivorous fishes in which plant material as food source is dominating are
also present in many other families of reef fish, like the Pomacentridae,
Gobiidae, Chaetodontidae, Blennidae, and Balistidae. Mugilids and
acanthurids feed on microphytobenthos and on periphyton in which plant
material dominates. Numerous herbivorous and omnivorous fish feed also
on the feces of predatory fish, thus increasing the efficiency of energy
utilization in reef food webs (Robertson 1982) Some hemiramphids
(Hemramphus dussumeri, H. brasiliensis) feed on phytoplankton and on
flakes of macrophytes and seagrass leaves, collecting them from the surface
film. Among the omnivorous fishes in which plant material comprises a large
portion of food are the angel fish Pomacanthus arguatus and P. paru, the
puffer Canthigaster rostrata, and the balistids Monocanthus ciliatus and M.
chinensis (Randall 1967; Conachear et al. 1979; Polunin 1989).
Herbivorous fish are strictly specialized with respect to the kinds of plant
food they consume. In experiments with the scarid Sparisoma radians it was
found that the scale of preference for consumed plants approximated the
following: (1) seagrass Thalassia covered with epiphytes, (2) bare seagrass
Halodule, (3) bare seagrass Thalassia, (4) the grass Syringodium, (5) the
alga Dictyota, (6) the alga Enteromorpha, (7) the alga Caulerpa, (8) the alga
Halimeda, and (9) the alga Penicillus. The scale of preference depends on
the nutritional quality of a given plant species and on its relative toxicity for
a given fish. Among those most preferted by fish are the seagrass Thalassia,
the algae Enteromorpha, Ulva, and Codium (Randall 1961; Earle 1972;
Hobson 1974; Ogden and Lobel 1978; Lobel and Ogden 1981). The grazing
pressure induced in plants the evolutional acquisition of defence
adaptations. Among these is the adaptation of some plants to grow in
turbulent surf zones, where their grazing by fish is disturbed (coralline algae,
filamentous algae, seagrasses). The thalloms of many algae are heavily
loaded and armed with calcareous material. This decreases their food quality
for fish (Turbinaria, Penicilius, Halimeda). Other algae are overloaded with
tannin impeding their digestion by fish, or are soaked with toxins which
repel their grazing. Out of 48 species of algae, which inhabit tbe shelf off
some islands south of Japan, 38 have toxic substances in their thalloms
(Hashimoto and Fusetani 1972). The thalloms of Sargassum contain tannins,
the alga Asparagopsis ketones, Caulerpa the toxin caulerpin, Laurencia
chlorides, and Dictopteris the toxin dictyopterin. The toxicity of many bluegreen algae is well known.
The grazing activity of herbivorous fish is one of the most powerful
ecologial factors controlling the structure, recruitment processes and