522
12 Species Case Studies
levels of aggregation and spawning during November and April. Outside of those
times no group spawnings, and only a single pair-spawning in August, was
observed. For blue tang aggregation and group-spawning were seen in all months
except June and November, although the winter period (December–March) certainly had larger aggregations and more spawning. Blue tang, however, had a very
clear lunar periodicity of aggregation spawning during the winter period, with
spawning occurring from just before the full moon until a few days after the new
moon (Fig. 12.60 ).
We believe that most ocean surgeonfi sh migrate to the spawning area each afternoon, because the densities of fi sh found in the study area during morning periods
Fig. 12.59 The black blocks show the days of confi rmed observation of aggregation and spawning
occurrence in ocean surgeonfi sh ( upper ) and blue tang ( middle ) against days when observations
were made that attempted to document aggregation occurrence ( lower )
Fig. 12.58 ( a ) Size comparison of male and female from spawning aggregation. ( a ) ocean
surgeonfi sh ( b ) blue tang
12 Species Case Studies
levels of aggregation and spawning during November and April. Outside of those
times no group spawnings, and only a single pair-spawning in August, was
observed. For blue tang aggregation and group-spawning were seen in all months
except June and November, although the winter period (December–March) certainly had larger aggregations and more spawning. Blue tang, however, had a very
clear lunar periodicity of aggregation spawning during the winter period, with
spawning occurring from just before the full moon until a few days after the new
moon (Fig. 12.60 ).
We believe that most ocean surgeonfi sh migrate to the spawning area each afternoon, because the densities of fi sh found in the study area during morning periods
Fig. 12.59 The black blocks show the days of confi rmed observation of aggregation and spawning
occurrence in ocean surgeonfi sh ( upper ) and blue tang ( middle ) against days when observations
were made that attempted to document aggregation occurrence ( lower )
Fig. 12.58 ( a ) Size comparison of male and female from spawning aggregation. ( a ) ocean
surgeonfi sh ( b ) blue tang