114
Plankton in Coral-Reef Waters
isolated traps the copepods contributed only about 20% of the total
zooplankton (Hobson and Chess 1979).
In the trap samples the copepod populations are often dominated by
cyclopids and mostrillids rather than by cal an ids as in the open ocean. In
such samples taken over the outer reef slope off Heron Island the reef
copepod species Calanopia and Thaumalens were the most numerous, but
not the calanoids Eucalanus or Undinula, most common in the nearby
oceanic waters (Sale et al. 1976a). The trap samples collected over the
Philippine reefs were dominated by the Cyclopoida. Over the fringing reef
of one the Namsu Islands the nocturnal zooplankton was dominated by the
copepods which numbered over 4000/m- 3 . This reef was short and therefore
the plankton community was here strongly influenced by the rich
zooplankton of the surrounding waters of the Gulf of Siam. Nevertheless,
even there a larger portion of the zooplankton was comprised by demersal
mysids and amphipods (Table 3.18). In the vast shallow lagoon of the
Koetivi Island, where the planktonic community was separated from the
direct influence of the oceanic waters, in the night samples the demersal reef
species of mysids amphipod and euphausiids absolutely predominated
(Table 3.17). In the nocturnal zooplankton samples collected over Heron
Island during high tide, the holoplankton comprised up to 90% of its total
number in waters up the reef-flat and closer to the reef edge where the
plankton community was strongly influenced by inflowing oceanic waters,
while up the patch reefs it comprised only about 50%. During ebb tide,
when the external influence was minimal, the zooplankton samples coIlected
over the patch reefs and reef flat contained almost exclusively the demersal
and meroplanktonic zooplankters - gammarids, mysids, polychaetes and the
decapod larvae (Table 3.19). A list of the commonest taxa of the demersal
and meroplanktonic reef zooplankton is given in Table 3.21.
Table 3.20. Common holoplanktonic genera of reef zooplankton
Taxonomic groups
Copepoda, (Calanoida)
Copepoda (Cyclopoida,
Monstrilloida)
Cladocera
Mysidae
Amphipoda
Chaetognata
Tunicata
Appendicularia
Syphonophora
Genera
Acartia, Eucalanus, Calocalanus, Clausicalanus, Paracalanus,
Calanopia, Canthocalanus, Nanocalanus, Candacia,
Euchata, Undinula, Temora, Centropages, Labidocera,
Bestiola
Pseudocyclops, Coricaens, Farranula, Oithona, Oncaea,
Sapphirina, Scolecetrichella, Monstrilla
Penilia, Evadne
Mysidium, Halichoeres, Thalassosoma
Brachicelsus, Eupronoe, Hyperietta, Hyphenia, Lestrigonus,
Synopia
Sagitta, Spadella
Doliolium, Salpa, Thalia
Oicopleura, Fritillaria
Abylopris, Chelophyes, Diphyes
Plankton in Coral-Reef Waters
isolated traps the copepods contributed only about 20% of the total
zooplankton (Hobson and Chess 1979).
In the trap samples the copepod populations are often dominated by
cyclopids and mostrillids rather than by cal an ids as in the open ocean. In
such samples taken over the outer reef slope off Heron Island the reef
copepod species Calanopia and Thaumalens were the most numerous, but
not the calanoids Eucalanus or Undinula, most common in the nearby
oceanic waters (Sale et al. 1976a). The trap samples collected over the
Philippine reefs were dominated by the Cyclopoida. Over the fringing reef
of one the Namsu Islands the nocturnal zooplankton was dominated by the
copepods which numbered over 4000/m- 3 . This reef was short and therefore
the plankton community was here strongly influenced by the rich
zooplankton of the surrounding waters of the Gulf of Siam. Nevertheless,
even there a larger portion of the zooplankton was comprised by demersal
mysids and amphipods (Table 3.18). In the vast shallow lagoon of the
Koetivi Island, where the planktonic community was separated from the
direct influence of the oceanic waters, in the night samples the demersal reef
species of mysids amphipod and euphausiids absolutely predominated
(Table 3.17). In the nocturnal zooplankton samples collected over Heron
Island during high tide, the holoplankton comprised up to 90% of its total
number in waters up the reef-flat and closer to the reef edge where the
plankton community was strongly influenced by inflowing oceanic waters,
while up the patch reefs it comprised only about 50%. During ebb tide,
when the external influence was minimal, the zooplankton samples coIlected
over the patch reefs and reef flat contained almost exclusively the demersal
and meroplanktonic zooplankters - gammarids, mysids, polychaetes and the
decapod larvae (Table 3.19). A list of the commonest taxa of the demersal
and meroplanktonic reef zooplankton is given in Table 3.21.
Table 3.20. Common holoplanktonic genera of reef zooplankton
Taxonomic groups
Copepoda, (Calanoida)
Copepoda (Cyclopoida,
Monstrilloida)
Cladocera
Mysidae
Amphipoda
Chaetognata
Tunicata
Appendicularia
Syphonophora
Genera
Acartia, Eucalanus, Calocalanus, Clausicalanus, Paracalanus,
Calanopia, Canthocalanus, Nanocalanus, Candacia,
Euchata, Undinula, Temora, Centropages, Labidocera,
Bestiola
Pseudocyclops, Coricaens, Farranula, Oithona, Oncaea,
Sapphirina, Scolecetrichella, Monstrilla
Penilia, Evadne
Mysidium, Halichoeres, Thalassosoma
Brachicelsus, Eupronoe, Hyperietta, Hyphenia, Lestrigonus,
Synopia
Sagitta, Spadella
Doliolium, Salpa, Thalia
Oicopleura, Fritillaria
Abylopris, Chelophyes, Diphyes