Spawning behaviour of the stoplight parrotfish Sparisoma Viride Bonnaterre, on Bonaire and Saba (Netherlands Antilles)
Student Report- University of Groningen
The reproductive behaviour of the stoplight parrotfish, Sparisoma viride Bonnaterre, was studied on two Caribbean islands of the Netherlands Antilles. In the northwest of Bonaire, the S. viride population living on the reef off Karpata exists of group fishes sharing a common home range in the shallowest parts of the reef and haremic fishes occupying most of the rest of the reef. Group fishes were not seen spawning in their feeding area, but some may spawn during about one hour daily close after sunrise on the reef slope at a depth of ca. 40 m. Haremic fishes mate consistently in the early morning in their territories. Harem males may spawn up to 12 times daily and can have extraharemic matings. Harem females spawn once or twice with the harem male, but additionally may mate at a deep spawning site. In the late afternoon the haremic fishes may spawn again for a shorter period and at a lower frequency. In the southwest of Bonaire, the S. viride population living on Tori's reef consists of only haremic individuals. The fishes mate exclusively in their territories during about one hour daily in the mid afternoon. Females spawn once or twice a day, while the harem males may spawn up to 6 times daily. Differences in the daily timing of spawning between these reefs are probably related to the different times of the day at which local currents are favourable for larval retention. In the northwest of Saba, the S. viride population living in Well's bay exists of nonharemic wandering fishes who spawn at a very low level in July. Seasonal spawning during the cooler months of the year is suggested. Differences in the timing of spawning might indicate tidal tracking. The variety in socio-sexual system at the three study sites suggests an adaptation to local variation in resources. Significant differences in the spawning behaviour of the fishes at the different localities are probably the result of the plastic nature of this behaviour varying under different environmental conditions.