Parrotfish

Parrotfish as a possible vector for zooxanthellae dispersal on coral reefs

The stoplight parrotfish, Sparisoma viride, is one of the dominant herbivores on the reefs of Bonaire. The effects of macroalgae herbivory have been well documented but the potential of S. viride to act as a shuttle for zooxanthellae remains unknown. Although coral is not considered a food item of S. viride they occasionally bite living tissue off of colonies of the scleractinians Montastrea annularis and Colpophyllia natans. Coral tissues contain large amounts of symbiotic dinoflagellates of the genus Symbiodinium, commonly referred to as zooxanthellae. Symbiodinium may be the key primary producer of the reef ecosystem and are found almost exclusively in symbiotic relationships with cnidarians. It is the aim of this article to examine the potential role of S. viride as a vector for transport of Symbiodinium throughout the reef environment as a result of parrotfish white spot biting. The purpose of coral biting is not known but territoriality is suspected in focused biting. Depending on the effect of parrotfish ingestion on the Symbiodinium cells, parrotfish white spot biting behavior could result in transport of Symbiodinium throughout the reef environment, increasing the genetic diversity of zooxanthellae populations.

This student research was retrieved from Physis: Journal of Marine Science I (Fall 2006)19: 33-37 from CIEE Bonaire.

Date
2006
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Author

Risky business: Ecological trade-offs of sub-tidal foraging behavior in parrotfish (Scaridae)

Parrotfish promote coral growth by controlling the abundance of algae on coral reefs. Although the importance of parrotfish herbivory on coral reefs has been noted; the feeding behavior of parrotfish is not fully understood. What is known is that territorial parrotfish defend the reef slope, forcing nonterritorial parrotfish to move to shallower water to feed. Ecological studies of predator-prey interactions suggest a correlation between risk and foraging behavior. The parrotfish on the reefs in Bonaire demonstrate a risky feeding behavior in the shallow sub-tidal zone that increases the risk of predation by osprey. A chain transect was used to determine the percent cover of algae in the shallow sub-tidal zone and reef flat. The percent cover of algae is greater in the shallow sub-tidal zone, meaning there is more food available in the habitat with higher risk of predation. In the shallow subtidal, parrotfish feed on turf algae and Padina in the same proportion as they occur on the benthos, meaning parrotfish are not feeding preferentially when in the shallow sub-tidal. To determine if there were diurnal feeding patterns in the shallow sub-tidal, observations were made 3 times per day. Initial phase parrotfish used the shallow sub-tidal zone more than terminal phase parrotfish and yellowtail parrotfish were the most abundant species. The species and phase that were most abundant may be a reflection of parrotfish populations on the reefs of Bonaire or a higher degree of crypsis. Tide levels had an impact on when the parrotfish could feed. Though most feeding occurred during morning and noonday hours, high and transitional tides were only found during these two time frames, which may explains the diurnal feeding behavior.

This student research was retrieved from Physis: Journal of Marine Science V (Spring 2009)19: 27-31 from CIEE Bonaire.

Date
2009
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Author

Parrotfish mucus cocoon production at night in Bonaire, N.A.

Many marine organisms use mucus to catch food, clean themselves, or for protection from predators. Some species of parrotfish (Family Scaridae) use mucus to build cocoons around themselves at night, which is thought to be a form of protection. Although there are reports of parrotfish constructing mucus cocoons, little is known about which specific species produces cocoons, where on the reef cocoons are used, or how prevalent the behavior is in Bonaire, N.A. The purpose of this study was to determine which species and phases of parrotfish construct cocoons, the distribution of cocoons from the reef slope to the shallow subtidal, and whether cocoons are being used for protection from predators. Observations took place between Oct. – Nov. 2009, after 23:00 h. Six depths were surveyed for parrotfish (1, 3, 6.5, 10, 15, and 20 m) and surveys were standardized by time. A guide diver assisted in keeping time, recording predators, and maintaining depth. Seven to 10 min was spent at each depth starting at 20 m and working up to 1 m. This study provides information on the nighttime ecology of parrotfish, which may be important for conservation of the species. During this study, two species of parrotfish, Scarus taeniopterus (princess parrotfish) and Scarus vetula (queen parrotfish), were found in cocoons; cocoons were only built along the reef slope, and none were found on the reef flat. Only terminal phase S. taeniopterus were found in cocoons, whereas terminal and initial phase S. vetula were found in cocoons.

This student research was retrieved from Physis: Journal of Marine Science VI (Fall 2009)19: 53-57 from CIEE Bonaire.

Date
2009
Data type
Other resources
Theme
Research and monitoring
Tags
Geographic location
Bonaire

Habitat use, nocturnal behavior, and differences between phases of five common parrotfish species in Bonaire, N.A.

Parrotfish are a common and important component of the fringing reefs ecosystem surrounding Bonaire, N.A. In the reef environment, large herbivores like parrotfish graze on macroalgae, allowing for higher coral diversity and abundance. This research studies habitat use among five common species of parrotfish, Scarus guacamaia, Sparisoma viride, Scarus taeniopterus, Sparisoma aurofrenatum, and Scarus vetula found on the leeward coast of Bonaire. The study was performed between Playa Lechi and Something Special dive sites, where transect tapes were placed at three depths representing different habitat types (shallow ridge, reef crest, and reef slope). After a brief recovery period (~ 1 hour), abundances of initial phase and terminal phase parrotfish were determined using SCUBA during midday, and again at night. Parrotfish density was higher during the day than at night and was significantly different among the three depths. Fisher’s PLSD post-hoc test showed that parrotfish density was significantly higher at 12 m than at 1 or 20 m. During the day, density of initial phase parrotfish was significantly higher than terminal phase, but there was no difference among the three depths. At night, there was no difference between the density of initial phase and terminal phase parrotfish, but there were more parrotfish found at 12 m than at 1 or 20 m. Based on the results of this study, more parrotfish are spotted during the day, parrotfish are found most often at 12 m during the night and day, and there are more initial phase parrotfish than terminal phase at all three depths during the day. Overall, significant findings include information about parrotfish habitat and differences between phases, with the additional note that 12 m depth seems to be an important habitat range for parrotfish in Bonaire.

This student research was retrieved from Physis: Journal of Marine Science VI (Fall 2009)19: 1-6 from CIEE Bonaire.

Date
2009
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Author

Behavior of the Princess parrotfish (Scarus taeniopterus): a comparison between daylight and sunset

Most animals are active either during the day or night, and at twilight, nocturnal and diurnal animals alike engage in behaviors to avoid predators, seek shelter, defend territory, or feed. Herbivorous fishes on coral reefs, such as parrotfishes, forage throughout daylight periods due to reliance on light and low nutrient content of algae. At sunset, parrotfishes seek cover to avoid predation during the night, resulting in less feeding and more aggressive behavior. This study compared how initial phase (IP) and terminal phase (TP) Princess parrotfish (Scarus taeniopterus) allocate time between daylight and sunset periods, specifically regarding feeding and aggressive behavior, on the fringing reefs of Bonaire, Dutch Caribbean. Using SCUBA, individual S. taeniopterus between 11 and 14 m depth were followed for 5 min after a 1 min acclimatization period, and time spent on each behavior was recorded. A two-way analysis of variance (ANOVA) was used to compare the amount of time S. taeniopterus spent feeding and in aggressive interactions between day and sunset periods, with phase and time of day as factors. Fish of both phases had a higher mean percent time feeding and a lower mean percent time being aggressive in the morning than at sunset. There was a significant difference in mean percent time feeding between phases, and TP fish had a significantly higher mean percent time being aggressive than IP fish. The changes in behavior found in this study increase the success of S. taeniopterus finding and keeping quality nighttime resting locations.

This student research was retrieved from Physis: Journal of Marine Science XII (Fall 2012)19: 45-51 from CIEE Bonaire.

Date
2012
Data type
Other resources
Theme
Research and monitoring
Tags
Geographic location
Bonaire
Author

The relationship between algae, depth, and abundance of terminal and initial phase parrotfish (Sparisoma viride and Scarus taeniopterus)

Coral reefs are undergoing phase shifts becoming dominated by algae rather than live coral. Algae on reefs is greatly impacted by herbivores such as parrotfish that use both the reef and shallow intertidal zone to feed. These two habitats are unique with differences in algal cover and algal community composition. The shallow intertidal may have greater risk of predation from ospreys and the habitat is more extreme in terms of turbulence and constantly changing microenvironments. It is unknown if feeding in the shallow intertidal zone provides a benefit that offsets the risk of feeding there. This study observed initial and terminal phases Sparisoma viride and Scarus taeniopterus to determine if there are differences in feeding by parrotfish between the shallow intertidal and the reef crest. The main goals of the study were 1) to compare algae from the shallow (higher predation risk) habitat to algae from the deeper (lower predation risk) habitats and 2) to compare abundance of terminal phase and initial phase. Transects at two different depths of 0.5 m and 10 m were placed at 10 different sites on the leeward side of Bonaire, Dutch Caribbean. Point intercept surveys and dry weight of algae samples were used to compare algal cover and fish surveys were conducted to measure parrotfish. Although the shallow intertidal zone had greater algal cover there was not a significant difference in abundance of parrotfish during either developmental stage studied, which may be explained by greater

This student research was retrieved from Physis: Journal of Marine Science XII (Fall 2012)19: 33-38 from CIEE Bonaire.

Date
2012
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Author

Parrotfish abundance and corallivory at the Yellow Sub dive site in Bonaire, Dutch Caribbean

Parrotfish are some of the most widely recognized reef fish in the world. They occupy almost every tropical reef on the planet, and through their eating behavior, dramatically transform ecosystems. Parrotfish mainly consume macroalgae, but have been known to consume coral and therefore have a potentially negative impact on coral fitness. Although parrotfish corallivory is a well-known behavior, little is known about why it occurs, and how severe the effects are on marine ecosystems. The purpose of this experiment was to quantify the amount of coral colonies that parrotfish feed on at the Yellow Sub dive site in Bonaire Dutch Caribbean. By collecting data on the extent of parrotfish corallivory, there will be a larger body of knowledge from which questions about parrotfish grazing can be answered. To carry out this experiment, 30 meter transect tapes placed at depths of nine and 15 meters were used to first catalogue all of the coral by species, size, and if it had been bitten by parrotfish. Next three transect swims were used to categorize all parrotfish by size, species, and any special behavior (i.e. coral consumption). Results showed a higher abundance of parrotfish in transects at nine meters than at 15 meters. Parrotfish preferred the coral species Montastraea annularis, but there was no relationship between the presence of parrotfish and the percentage of coral bitten.

This student research was retrieved from Physis: Journal of Marine Science XII (Fall 2012)19: 16-21 from CIEE Bonaire.

Date
2012
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire

Caribbean parrotfish foraging: An interspecific comparison of algal preferences

In recent decades, reduced grazing pressure caused by a die-off of Diadema antillarum and the overexploitation of herbivorous fishes have facilitated a phase shift from coral to algal dominated reefs. Thus, conservation of herbivorous fishes has become increasingly important on coral reefs. In the Caribbean reefs, parrotfish are the dominant herbivores. Studies have been conducted on parrotfish grazing, but there is a lack of knowledge about specific algal preferences. This study examined differences in bite frequencies on algal types and algal preferences of the most common parrotfish species of Bonaire, Dutch Caribbean. Mean bite frequencies (bites 30 min-1 ) and preferences were determined by offering algal plates with Padina sp., Ulva sp., Sargassum sp., and turf algae to parrotfish on the coral reef flat. During field observations, data was collected on the number of bites taken and algal type grazed by each individual parrotfish. Parrotfish as a group, and individual species (Sparisoma rubripinne, Scarus viride, and Sparisoma aurofrenatum), demonstrated significant differences in mean bite frequencies on algal types offered. There were also significant differences in mean bite frequencies among the three parrotfish species. All species of parrotfish, collectively and individually, demonstrated preferences for Padina sp. and avoidances for all other algal types offered. Determining which algal types parrotfish graze, and how grazing differs among parrotfish species is ecologically important. The results provide an understanding of how the selective pressures of specific herbivores may help regulate harmful macroalgae, and suggest the importance of maintaining the diversity of herbivorous fishes on the reef.

This student research was retrieved from Physis: Journal of Marine Science XIV (Fall 2013)19: 110-117 from CIEE Bonaire.

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

Influence of habitat on defecation behavior of queen (Scarus vetula) and princess (Scarus taeniopterus) parrotfish

Herbivores are important structuring agents for ecosystems worldwide. While effects of grazing by herbivorous fish are well studied, their roles in organismal dispersal have only recently become a topic of interest. Location preference and range of defecation may indicate the importance of their contribution to organism spreading. This study therefore examined the distribution and frequency of defecation of the princess parrotfish (Scarus taeniopterus) and queen parrotfish (Scarus vetula) between coral reef and sand flat habitats. Observations were performed using SCUBA in Bonaire, Dutch Caribbean. Target species were observed for 20-minute trials in each habitat. Defecation frequency, bite frequency, maximum distance between defecations, and location of defecation were recorded and averaged for each species in each habitat, and compared between species and habitats through two-way analysis of variance (ANOVA). Additionally, unique food sources observed during trials were sampled and examined in the lab. S. taeniopterus individuals were found to defecate significantly less and have smaller maximum distance between defecations within the reef habitat than the sand habitat, while S. vetula did not show significant behavioral changes for any of the variables between the two habitats. Lab results also suggest that S. taeniopterus may be opportunistic omnivores. This study offers insight to behavioral plasticity and specificity to habitat type, and provides a broader understanding of dietary plasticity and ecological roles for S. taeniopterus and S. vetula.

This student research was retrieved from Physis: Journal of Marine Science XIV (Fall 2013)19: 1-13 from CIEE Bonaire.

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

Status and Trends of Bonaire’s Reefs, 2011. Cause for grave concerns

Unusually warm ocean temperatures surrounding Bonaire during the late summer and fall of 2010 caused 10 to 20 % of corals to bleach (Fig. 1). Bleaching persisted long enough to kill about 10 % of the corals within six months of the event (Steneck, Phillips and Jekielek Chapters 2A – C). That mortality event resulted in the first significant decline in live coral at sites monitored since 1999 (Fig. 2). Live coral declined from a consistent average of 48 % (from 1999 to 2009) to 38 % in 2011 (Steneck Chapter 1). This increase in non-coral substrate increased the area algae can colonize and the area parrotfish must keep cropped short (Mumby and Steneck 2008). For there to be no change in seaweed abundance would require herbivorous fish biomass and population densities to increase, but they have been steadily declining in recent years. This decline in parrotfish continues despite the establishment of no-take areas (called Fish Protection Areas – FPAs) and the recent law that completely bans the harvesting of parrotfish. The other major herbivore throughout the Caribbean is the black spined sea urchin, Diadema antillarum. However, since 2005 Diadema abundance has steadily declined. Damselfishes continue to increase in abundance (except in FPAs) and their aggressive territoriality reduces herbivory where they are present. These declines in herbivory resulted in a marked increase in macroalgae (Steneck Chapter 1). Although patchily distributed, algae on some of Bonaire’s reefs are approaching the Caribbean average (Kramer 2003). All research to date indicates that coral health and recruitment declines directly with increases in algal abundance (e.g., Arnold et al 2010).
On the bright side, predatory fishes are increasing in abundance in general but increasing most strongly in FPAs. Typically, responses to closed areas take 3 - 5 years to begin to manifest themselves. Predators of damselfishes have increased significantly in FPA sites and there, damselfish abundances are trending downward. These trends are the first signs of changes in the FPAs, and they are encouraging.
Overall, Bonaire’s coral reefs today are more seriously threatened with collapse than at any time since monitoring began in 1999.
 
Monitoring Results
The abundance of live coral at the monitoring sites has been remarkably constant since 1999. However, the bleaching related mortality event (Fig. 1) resulted in the first marked decline in live coral.
Seaweed abundance (“macroalgae”) increased sharply in 2011. While the greatest increase in algae occurred at the 18th Palm site where effluent could have increased nutrient levels, most of the other sites showed marked increases in algal abundance (see Steneck Chapter 1). Coralline algae, which has been shown to facilitate coral recruitment, remains at or near unprecedentedly low levels (Fig 2). Herbivory from parrotfishes and the grazing sea urchin Diadema antillarum remains at or near the lowest levels recorded since monitoring began in 1999 (Fig. 3 and see Cleaver Chapter 5). Herbivory from parrotfish is widely thought to be most important (e.g., Steneck and Mumby 2008) but territorial damselfishes can negate parrotfishes’ positive effects by attacking grazing herbivores and preventing them from effectively grazing (Arnold et al 2010). Damselfish abundances have trended upward in recent years (Fig. 3). However, there is a hint of a reversal to this trend in the FPAs (see Arnold Chapter 3). This reversal is consistent with the possibility that areas without fishing have elevated abundances of damselfish predators such as species of groupers and snappers (Randall 1965)  
Predatory fishes including snappers, groupers, barracuda, grunts and others increased in abundance at our monitored sites (Fig. 4 and see DeBey Chapter 6a). Specific predators known to eat damselfishes (see Preziosi Chapter 6b) show variable population densities with only a hint of an increase in 2011.   
Predatory fishes increased in abundance in both biomass (most striking) and population densities (Fig. 5). While biomass of predators in FPA and control sites is identical, the population density of predators is slightly greater at FPA sites
Coral recruitment remained lower than recorded in 2003 and 2005 (Fig. 6). However, the abundance of juvenile corals was higher in 2011 than was quantified in 2009

Date
2011
Data type
Research report
Theme
Research and monitoring
Report number
5
Geographic location
Bonaire