Parrotfish

Activity budget of the princess parrotfish (Scarus taeniopterus): a comparison between daylight and sunset periods

Abstract:

Most animals are active either during the day, night, or twilight, and transition periods between these times exhibit interesting behavior. Actions may be related to avoiding predators, seeking shelter, defending territory, feeding, or other interests. Herbivorous fishes on coral reefs, such as parrotfishes, forage constantly throughout daylight periods due to inefficient feeding and reliance on light. At sunset, parrotfishes seek cover under which to rest at night, to conserve energy and avoid predation. To do so, parrotfish decrease feeding and increasing migration and aggression to do so. This study compared how initial phase (IP) and terminal phase (TP) princess parrotfish (Scarus taeniopterus) allocate time between daylight and sunset periods, specifically regarding time spent feeding and being aggressive. Observations were performed using SCUBA at Yellow Sub dive site on Bonaire, Dutch Caribbean. Individuals of S. taeniopterus were followed for 1 min (to allow for acclimatization), followed by 5 min of behavioral observation. Percent time spent on each behavior was calculated and averaged across each category (e.g. IP, daylight), and mean percent time spent feeding and being aggressive were tested using a two- way analysis of variance (ANOVA), with phase and time of day as factors. Both IP and TP fish had a higher mean percent time feeding and a lower mean percent time being aggressive in the morning than at sunset, and time of day and phase were both significant factors affecting variation in both behaviors. The results of this study give insight into the adaptations parrotfish have developed to increase survival. 

Date
2013
Data type
Research report
Theme
Research and monitoring
Geographic location
Bonaire
Author

An age-based demographic analysis of the Caribbean stoplight parrotfish Sparisoma viride

The parrotfish Sparisoma viride is an abundant and ecologically important member of the tropical NW Atlantic reef fish fauna. Sagittal otoliths of 417 individuals were analysed to estimate age-based demographic variables at 4 localities (Lee Stocking Island, Barbados, Los Roques Archipelago and the San Blas Archipelago) spanning 14° of latitude. The sampling localities ranged from an area protected from trap- and net-based reef fisheries (Los Roques) to an area supporting a dense human population and sustained trapping and spearing for reef fishes including S. viride (Barbados). Examination of sectioned sagittal otoliths from each locality revealed regular increments in the sagittal matrix. A preliminary validation at San Blas was consistent with these increments being annual check marks. These increments provided estimates of age structure, maximum longevities and mortality rates for the 4 study populations of S. viride. Von Bertalanffy growth functions fitted to each size-at-age plot generated similar growth curves from 3 of these 4 localities. The exception was Lee Stocking, where fish grew faster and reached a substantially larger size than those from the other 3 localities. Further analysis of the growth curves demonstrated that the differences between Lee Stocking and the other localities were attributable to more rapid growth over the first 4 yr of life. Age-based growth curves derived from the Los Roques population were very similar to a size-based curve generated by an independent study on S. viride carried out in Bonaire, adjacent to Los Roques. Maximum longevities for all 4 of our populations varied from 7 to 9 yr. Mortality rates generated from catch curve analysis were also similar among localities and suggest that maximum life spans do not exceed 12 yr. This result differs from that obtained at Bonaire, where repeated censuses of tagged fish suggest 30 yr maximum longevity. Abundances of S. viride varied 3-fold among localities, being highest at Los Roques (protected from reef fishing), lowest at Barbados (high fishing) and Lee Stocking (low fishing). Thus our age-based study suggests that S. viride is a relatively short-lived fish with consistent demographic parameters over a range of localities, latitudes and fishing intensities. 

Date
2003
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Bonaire