Problems of Monitoring and Rational Use of Reef Resources
425
for the fabrication of agar, as a fodder, for raising herbivorous fish in a
complex aquaculture enterprise, and also as food for people, since the above
algae are edible. On reefs of Palau the gastropods Trochus were successfully
cultivated (Helsinga and Hillman 1981). The bivalve Pinna is cultivated on
the reefs of Vietmam and on reefs of the Philippines Tridacna (Alcala 1981).
The young of Tridacna are raised so as to revive their populations
exterminated by illegal trade (Helsinga et al. 1984). On the Bahamas a large
spider crab Mithrax spinisissimus was cultivated (Munro and Williams 1985).
The raising of the noble rose and black corals on reefs is also planned (Grigg
1982), as well as the raising of large predatory fish. The fishermen of
Thailand raise groupers and reef perches in cages, feeding them with small
pelagic fish. Because they are territorial and are not grazed they could be
raised even without cages (if the sharks are exterminated), being fed on the
same small fish as found in places where they live.
The positive effects of the introduction of new species on reefs have been
proved on Hawaii (Brock 1960; ada and Parrish 1981). The fish fauna on
reefs had been poor there, with large serranid, lutjanid and lethrinid fish
and with edible molluscs, crabs and lobsters. Therefore, between 1920-1950
several tens of species had been introduced. These measures significantly
increased the resources of reefs and catches increased. Among the species
most successfully introduced, forming large stocks on Hawaiian reefs were
the fish: Lutjanus fulvus, L. kasmira, Cephalopholis guttatus, the molluscs
Venerupis philippinarium, Cytherea merethrix, the lobster Procambarus
clarkii, and the crab Seylla serrata.
While the problem regarding the use of artificial reefs to improve fish
productivity of natural reefs is still disputed, it has been proved that their
construction might significantly enhance the fish stocks (Randall 1963;
Ogawa 1973). For example, on an artificial reef constructed from hollow
concrete blocks in the vicinity of a natural reef in Lameshur Bay (Virgin I.),
after 1.5 years, the biomass of fish was about one order more than on the
nearly reefs. On the artificial reefs, constructed from 500 spare tires in
Florida, the composition and abundance of fish fauna were comparable to
those in the natural neighboring patch reef. Within 1-2 years their surface
became overgrown with periphyton, macrophyles and sessile reef fauna
(Tsuda and Kami 1973). In tropical shelf areas the artificial reefs, even if
they had been established on soft bottom far from natural reefs, soon
become colonized by fish fauna, including typical reef fish like
chaetodontids, apogonids, chromises, pomecentrids, caesionids, and sea
perches from the genera Haemulon, Lethrinus, and Luthjanus. In the
vicinity of such artificial reefs shoals of small pelagic fish appear.
Off the coast of the USA, either in tropical and temperate zones, now
several thousands of artificial reefs exist, most of which testify to former
oil-drilling platforms, now abandoned. Having numerous underwater
constructions with vast areas, these platforms function as artificial reefs. In
the Mexican Gulf alone they number over 3000. Each year there, and also
425
for the fabrication of agar, as a fodder, for raising herbivorous fish in a
complex aquaculture enterprise, and also as food for people, since the above
algae are edible. On reefs of Palau the gastropods Trochus were successfully
cultivated (Helsinga and Hillman 1981). The bivalve Pinna is cultivated on
the reefs of Vietmam and on reefs of the Philippines Tridacna (Alcala 1981).
The young of Tridacna are raised so as to revive their populations
exterminated by illegal trade (Helsinga et al. 1984). On the Bahamas a large
spider crab Mithrax spinisissimus was cultivated (Munro and Williams 1985).
The raising of the noble rose and black corals on reefs is also planned (Grigg
1982), as well as the raising of large predatory fish. The fishermen of
Thailand raise groupers and reef perches in cages, feeding them with small
pelagic fish. Because they are territorial and are not grazed they could be
raised even without cages (if the sharks are exterminated), being fed on the
same small fish as found in places where they live.
The positive effects of the introduction of new species on reefs have been
proved on Hawaii (Brock 1960; ada and Parrish 1981). The fish fauna on
reefs had been poor there, with large serranid, lutjanid and lethrinid fish
and with edible molluscs, crabs and lobsters. Therefore, between 1920-1950
several tens of species had been introduced. These measures significantly
increased the resources of reefs and catches increased. Among the species
most successfully introduced, forming large stocks on Hawaiian reefs were
the fish: Lutjanus fulvus, L. kasmira, Cephalopholis guttatus, the molluscs
Venerupis philippinarium, Cytherea merethrix, the lobster Procambarus
clarkii, and the crab Seylla serrata.
While the problem regarding the use of artificial reefs to improve fish
productivity of natural reefs is still disputed, it has been proved that their
construction might significantly enhance the fish stocks (Randall 1963;
Ogawa 1973). For example, on an artificial reef constructed from hollow
concrete blocks in the vicinity of a natural reef in Lameshur Bay (Virgin I.),
after 1.5 years, the biomass of fish was about one order more than on the
nearly reefs. On the artificial reefs, constructed from 500 spare tires in
Florida, the composition and abundance of fish fauna were comparable to
those in the natural neighboring patch reef. Within 1-2 years their surface
became overgrown with periphyton, macrophyles and sessile reef fauna
(Tsuda and Kami 1973). In tropical shelf areas the artificial reefs, even if
they had been established on soft bottom far from natural reefs, soon
become colonized by fish fauna, including typical reef fish like
chaetodontids, apogonids, chromises, pomecentrids, caesionids, and sea
perches from the genera Haemulon, Lethrinus, and Luthjanus. In the
vicinity of such artificial reefs shoals of small pelagic fish appear.
Off the coast of the USA, either in tropical and temperate zones, now
several thousands of artificial reefs exist, most of which testify to former
oil-drilling platforms, now abandoned. Having numerous underwater
constructions with vast areas, these platforms function as artificial reefs. In
the Mexican Gulf alone they number over 3000. Each year there, and also