545
12 Species Case Studies
12.23.2 Other Species of Balistids
The characteristics of nest-digging and guarding of eggs by balistids allows detection of aggregation and spawning for periods of a day or more, whereas the evidence
of other fi shes aggregating and spawning is often gone in a few minutes to a few
hours, simplifying monitoring of aggregation occurrence.
The reproduction of the large titan triggerfi sh, Balistoides viridescens , is largely
unreported, but appears similar to that of the yellowmargin triggerfi sh (Fig. 12.79 ),
including attacks on divers approaching guarded nests. For other genera, there are
spotty reports of spawning. In the Indo-west Pacifi c Kuwamura ( 1997 ) found both
sexes of Picassofi sh, Rhinecanthus aculeatus , maintained long-term territories; some
for up to 8 years, thus this species may not be considered an aggregator (no increase
in density of adults). Male territories overlapped 2–3 female territories with only
Fig. 12.78 ( a ) Nests of yellowmargin triggerfi sh at Ulong Channel on rubble bottom 8–12 m deep
where aggregated groupers transit. The groupers are attacked if they venture too close to nests. ( b )
Multiple triggerfi sh nests converging on a sandy bottom. Yellowmargin triggerfi sh guarding and
aerating the eggs (Photos: Patrick L. Colin)
12 Species Case Studies
12.23.2 Other Species of Balistids
The characteristics of nest-digging and guarding of eggs by balistids allows detection of aggregation and spawning for periods of a day or more, whereas the evidence
of other fi shes aggregating and spawning is often gone in a few minutes to a few
hours, simplifying monitoring of aggregation occurrence.
The reproduction of the large titan triggerfi sh, Balistoides viridescens , is largely
unreported, but appears similar to that of the yellowmargin triggerfi sh (Fig. 12.79 ),
including attacks on divers approaching guarded nests. For other genera, there are
spotty reports of spawning. In the Indo-west Pacifi c Kuwamura ( 1997 ) found both
sexes of Picassofi sh, Rhinecanthus aculeatus , maintained long-term territories; some
for up to 8 years, thus this species may not be considered an aggregator (no increase
in density of adults). Male territories overlapped 2–3 female territories with only
Fig. 12.78 ( a ) Nests of yellowmargin triggerfi sh at Ulong Channel on rubble bottom 8–12 m deep
where aggregated groupers transit. The groupers are attacked if they venture too close to nests. ( b )
Multiple triggerfi sh nests converging on a sandy bottom. Yellowmargin triggerfi sh guarding and
aerating the eggs (Photos: Patrick L. Colin)