Wormlike Animals
185
1977). Another way is to dissolve the lime blocks with acid (Hutchings and
Weate 1978). Inevitably, during the precedure of cutting and breaking up
the rock a large, if not the largest, part of vagile fauna may escape. For this
reason, data on the taxonomy and the density of the polychaete fauna in
reefs seem to underestimate significantly the latter (Fauchald 1974). One
possible nondirect way to solve this problem is to place porous lime blocks
of 1 dm 3 size on the bottom for 2-3 years (Hutchings 1981, 1985). During
this period the block is inhabited by polychaetes from the surrounding
biotope. In such blocks, kept for 2 years on the Lizard Island reef-fiat, 144
species of polychaetes were discovered. This number was far greater than it
was possible to find in the samples of natural fiat rocks. In the blocks the
polychaete fauna was dominated by the genera: Polydora, Syllis, Hydroides,
Ceratonereis, and Nematonereis. The recruiting of polychaete fauna into
these blocks proceeded mainly through the settling of their larvae from the
water column. An important stage in this process was the initial appearance
of the boring sipunculid worms. They bored holes in block walls which were
then occupied by other polychaetes.
The total species number of polychaete fauna on a separate-standing reef
was: in the western Atlantic region 100-130, on the Bahamas 46, at the
Tulear reefs 118, at Guam 29, at reefs of Thailand and Sumatra 76, at the
Enivetak atoll 132, and at reefs of the southern GBR about 140 (Kohn and
Lloyd 1973; Hutchings 1974, 1985; Vittor and Johnson 1977; Peyrot and
Clausade 1977; Devaney et al. 1987). Most numerous were the species of
Syllidae and Eunicidae. These families and sometimes also the serpulids
formed the bulk of the total number of the polychaete fauna. A main
portion of their biomass was composed usually of eunicids, nereids and
capitellids. At the reefs of the Indo-Pacific in reef-fiat biotopes the number
of species of polychaetes varied within 10-20 and their total number within
10-60 x 10 3 m- 2 , with a domination of small syllids (Kohn and Lloyd 1973;
Hutchings 1974, 1985; Peyrot-Clausade 1977; Buzhinskaya et al. 1980; cf.
Fig. 5.4). On reefs of the western Atlantic, in the same biotopes the eunicids
and serpulids were most numerous (Vittor and Johnson 1977). Shannon's
index of species diversity of polychaete communities in biotopes of fiats was
usually very high: H = 1.5-2.8. In shallow soft bottom biotopes with
seagrasses and seaweeds the polychaete fauna is less abundant.
Nevertheless, their biomass compose a significant portions of the benthos
there. Their total numbers attained 5-20 x 10 3 m- 2 and their biomass
1O-100gm- 2 (Thomassin et al. 1976,1982; Ausari et al. 1991). Among the
errant polychaetes the eunicids (Marphysa), the capitellids (Dasybranchus),
the polynoids (Lepidonotus), the nereids (Nereis, Perinereis) and the
glycerids (Glycera) were most numerous. The sedentary polychaetes
Chaetopterus, Mesochaetopterus, Terebellides, Prionospio were here also
usual components of benthic fauna. The comunity structures of the
polychaete communities vary on different reefs, being dependent upon the
abundance of plankton and detritus on them. On reefs with an abundant
185
1977). Another way is to dissolve the lime blocks with acid (Hutchings and
Weate 1978). Inevitably, during the precedure of cutting and breaking up
the rock a large, if not the largest, part of vagile fauna may escape. For this
reason, data on the taxonomy and the density of the polychaete fauna in
reefs seem to underestimate significantly the latter (Fauchald 1974). One
possible nondirect way to solve this problem is to place porous lime blocks
of 1 dm 3 size on the bottom for 2-3 years (Hutchings 1981, 1985). During
this period the block is inhabited by polychaetes from the surrounding
biotope. In such blocks, kept for 2 years on the Lizard Island reef-fiat, 144
species of polychaetes were discovered. This number was far greater than it
was possible to find in the samples of natural fiat rocks. In the blocks the
polychaete fauna was dominated by the genera: Polydora, Syllis, Hydroides,
Ceratonereis, and Nematonereis. The recruiting of polychaete fauna into
these blocks proceeded mainly through the settling of their larvae from the
water column. An important stage in this process was the initial appearance
of the boring sipunculid worms. They bored holes in block walls which were
then occupied by other polychaetes.
The total species number of polychaete fauna on a separate-standing reef
was: in the western Atlantic region 100-130, on the Bahamas 46, at the
Tulear reefs 118, at Guam 29, at reefs of Thailand and Sumatra 76, at the
Enivetak atoll 132, and at reefs of the southern GBR about 140 (Kohn and
Lloyd 1973; Hutchings 1974, 1985; Vittor and Johnson 1977; Peyrot and
Clausade 1977; Devaney et al. 1987). Most numerous were the species of
Syllidae and Eunicidae. These families and sometimes also the serpulids
formed the bulk of the total number of the polychaete fauna. A main
portion of their biomass was composed usually of eunicids, nereids and
capitellids. At the reefs of the Indo-Pacific in reef-fiat biotopes the number
of species of polychaetes varied within 10-20 and their total number within
10-60 x 10 3 m- 2 , with a domination of small syllids (Kohn and Lloyd 1973;
Hutchings 1974, 1985; Peyrot-Clausade 1977; Buzhinskaya et al. 1980; cf.
Fig. 5.4). On reefs of the western Atlantic, in the same biotopes the eunicids
and serpulids were most numerous (Vittor and Johnson 1977). Shannon's
index of species diversity of polychaete communities in biotopes of fiats was
usually very high: H = 1.5-2.8. In shallow soft bottom biotopes with
seagrasses and seaweeds the polychaete fauna is less abundant.
Nevertheless, their biomass compose a significant portions of the benthos
there. Their total numbers attained 5-20 x 10 3 m- 2 and their biomass
1O-100gm- 2 (Thomassin et al. 1976,1982; Ausari et al. 1991). Among the
errant polychaetes the eunicids (Marphysa), the capitellids (Dasybranchus),
the polynoids (Lepidonotus), the nereids (Nereis, Perinereis) and the
glycerids (Glycera) were most numerous. The sedentary polychaetes
Chaetopterus, Mesochaetopterus, Terebellides, Prionospio were here also
usual components of benthic fauna. The comunity structures of the
polychaete communities vary on different reefs, being dependent upon the
abundance of plankton and detritus on them. On reefs with an abundant