Recent studies show that late stage pelagic larval fish are not simply drifting with the currents as formerly believed, but are in some cases strong swimmers and more than capable of swimming against the ambient flow. There is evidence that larval fish may select specific habitats in which to settle. Although little is understood about their sensory abilities, both sound and smell have been linked to settlement of coral reef larvae (Leis 1997). On Bonaire, Netherlands Antilles, coral reefs, mangrove forests, and seagrass beds provide refuge and food for young fish. Some fish species are thought to spend the juvenile life stages in mangroves and seagrasses and abundances of certain adult reef fish species have been shown to be greater in coral reefs with surrounding seagrasses and mangroves (Mumby 2004). Larval fish may be able to select environments for settlement based on biological attractions detected by certain senses (Lecchini 2005). This study investigates the potential differences in the larval fish recruiting to mangrove and seagrass habitats with larval fish recruiting to coral reef habitats. Samples of larval fish were taken on the three nights surrounding the November new moon. Light traps and dip nets were used at two different sites, one a mangrove/seagrass habitat, and the other a coral reef habitat. Larger numbers of larval fish and more families were represented in the samples taken in the coral reef habitat than the mangrove/seagrass habitat.
This study examines the importance of color in camouflage of the West Atlantic Trumpetfish, Aulostomus maculatus during shadow stalking behavior. Shadow stalking is a foraging technique where A. maculates disguises itself to prey by aligning along the dorsal line of another reef fish. The study was done in Bonaire, Netherland Antilles between October and November 2007. Data was taken snorkeling in the shallow waters in front of Kralendijk on the leeward side of the island and behavioral changes were recorded. Two morphotypes of A. maculates common to the study site were identical in size and phase range (shade) and varied only in the presence or absence of a blue nose. They provided the basis for testing the hypothesis that the blue-nosed A maculatus morph would shadow reef fish that are also blue/green more frequently. Though the blue-nosed A. maculates did not appear to shadow blue/green fish more often, an analysis of different morphotypes (blue-nosed or brown) and phases (pale or dark) in the area showed unexpected trends. Mainly that pale and brown A. maculates shadow a higher percentage of blue/green fish than dark or blue-nosed A. maculates respectively.
The change in the mean trophic level of fish assemblages can be used as an indicator of fishing pressure. To gain a more detailed understanding of changes in trophic level, trophic spectra can be derived using a 3-point moving average technique. The mean trophic level was used to determine differences between reef fish assemblages inside and outside fish protected areas (FPAs) around Bonaire, Dutch Caribbean. Additionally, mean trophic levels of reefs spanning the entire Caribbean were calculated to enable comparison based on their level of degradation by anthropogenic disturbances. No difference was seen between the mean trophic level of sites inside and outside the FPAs, possibly due to the fact that the FPAs have only been in place for 4 years. Differences in mean trophic levels across the Caribbean were significant but did not correspond to estimated reef health, implying that mean trophic level may not be a good indicator of reef health. Reef fish assemblages seem to be affected by a variety of factors, not simply fishing pressure or reef health.
Reef fishes and invertebrates are quickly losing their habitats due to widespread coral degradation. Artificial reefs are entering the spotlight as alternatives to this problem because they provide marine life with habitats. The role that artificial reefs will play in marine resource management is still unknown, partly because artificial reefs are often overlooked as alternatives due to a lack of knowledge about them. Without the right information on artificial reef placement, the reefs may be used inefficiently. This study focused on how reef fish assemblages and invertebrate coverage can be influenced by artificial reef isolation, distance from the natural reef. This study was conducted in Bonaire, Dutch Caribbean, at the Yellow Sub dive site. Six mooring blocks were visually censused for fish biodiversity and photographed to find percent invertebrate coverage. Three of the blocks were weakly isolated and the other three were strongly isolated from the natural reef. The study took place over a five-week span from September through October 2012. The only significant difference between the weakly and strongly isolated blocks was that there was higher fish abundance on the weakly isolated blocks. Fish biodiversity and percent invertebrate cover did not differ significantly between the two block isolations. A better understanding of what factors allow for more suitable habitats on artificial reefs will contribute to conservation efforts and could increase reef fish and invertebrate biodiversity and abundance.
Diving on reefs is a great means for tourism around the world. The impacts of divers differ based on experience and if there is something of high interest to observe. Recreational divers enjoy taking pictures or videos to capture the organisms observed. One organism of great abundance on Bonaire’s reefs is the bicolor damselfish, Stegastes partitus. They are a planktivorous reef fish that feeds on plankton in the water column. An increase in flash photography, due to the increase in diving, may affect essential behaviors, such as feeding and predator avoidance. The bite rate for S. partitus will decrease under the influence of a stimulus, such as light. The S. partitus individual will have the same time in refuge and reemergence times as those affected by a predator. Individuals were observed under three treatment groups: hand (artificial predator), light, and control. For each 10- minute observation period, the bite rate, reemergence time, and time in refuge was recorded. The treatment groups had no effect on the time spent in refuge of bicolor damselfish. The results did have an effect on the bite rate, as well as, show that the presence of a current could affect the reemergence time, depending on the treatment group. This study provided evidence that flash photography can have some effects on fish behavior. Because this topic has not been observed in great detail, further studies on this topic should be conducted.
This student research was retrieved from Physis: Journal of Marine Science XVIII (Fall 2015)19: 34-39 from CIEE Bonaire.
The Sharpnose Pufferfish, Canthigaster rostrata, as well as other species within the Tetraodontidae family are common reef fish found in tropical and subtropical waters. Past studies on some of the 36 species within the same genus share consistent observations on their haremic structure, territorial nature, and spawning patterns. Although research has been done specifically on C. rostrata in Panama, little is known about C. rostrata in the Lesser Antilles. This study provides ecological data on the correlation between territory size and complexity, as well as the size and abundance of individual C. rostrata. Over the course of five weeks, the size, abundance, and behavior of C. rostrata were recorded. Data was collected at five specific structures at a local dive site known as Yellow Submarine. A custom-designed complexity chart was made to rank these structures in order of complexity. Results indicated that structure volume is a criterion that affects complexity, but that it is not the main one. Results also showed that more complex structures hosted more individuals on average from highest to lowest (mean ± SD), was 5.62 ± 1.18, 4.12 ± 1.80, 2.14 ± 1.06, 1.20 ± 1 and 1.62 ± 0.91. More complex structures also hosted larger individuals of C. rostrata on average from highest to lowest (mean ± SD), was 4.81 cm ± 0.6, 3.06 cm ± 0, 2.9 ± 0.35, 2.55 ± 0.44, and 2.43 ± 0.5.
This student research was retrieved from Physis: Journal of Marine Science XIX (Spring 2016)19: 22-27 from CIEE Bonaire.
The coral reefs of Bonaire have been reported to be one of the most pristine reefs, with the reefs on the leeward coast of Bonaire regarded as one of the healthiest reefs of the Caribbean (NOAA 2008; Sommer et al. 2011; Jackson et al. 2014). Nonetheless, Bonaire is a growing popular tourist destination and the reefs have been increasingly exposed to anthropogenic stress in addition to natural disturbances. The overarching question of this project addressed the large and small-scale variation in benthic and fish communities of the reefs on the leeward side of Bonaire. However, this report focuses on describing the fish communities of these reefs, and looks into the effect of benthic community composition on fish community assemblages. Our fieldwork set-up allowed us to look into large scale differences (between zones), and small-scale differences (between sites, within zones). Additionally, since fish observations were done on the same transect as benthic measurements, with this set-up, we were also able to look into the effects of benthic composition on fish community composition. To visualize trends in species biomass composition we did a cluster analysis and plotted the clusters in a non-metric multidimensional scaling (nMDS). To see which benthic categories had an effect on fish composition, we plotted an environmental fit (Envfit at P < 0.05) with benthic categories. Also, to check the effect of site location, the clusters are plotted on a Bonaire map. We report clear differences in fish species richness, diversity and biomass between the two zones, with the deeper zone showing greater numbers. There was greater variation in both fish and benthic communities in the lower-terrace (the shallower zone), and this variation reflected the degradation gradient along the leeward coast of Bonaire. Sites located around the busy tourist center showed a trend towards lower fish biomass and richness, lower coral cover and diversity, and lower topographic complexity. Whereas sites in the same zone (same depth) located within the marine park, a protected area, scored highest in the same categories. The drop-off, a deeper zone, showed far less variation in all categories. From these results it can be concluded that effects of habitat degradation on benthic communities reflect on fish communities, especially in shallower zones. Our results also demonstrate that protected areas have a positive effect on benthic and fish communities, reiterating the importance of these areas. The inclusion of Bonaire fishery data would provide an interesting insight and would clarify even more the variation found across sites.
Coral reefs throughout the Caribbean have suffered the effects of human activities, including overfishing, nutrient pollution, and global climate change. Yet despite systematic deterioration of reef health, there still exists appreciable variability of reef conditions across Caribbean sites. The mid-depth (20 m) fringing reefs of Bonaire and Curaçao, in the leeward Netherlands Antilles, remain healthier than reefs on many other Caribbean islands, supporting relatively high fish biomass and high coral cover. Approximately one half of the fish biomass is composed of planktivorous species, with the balance comprised of herbivorous and carnivorous species. Only a small fraction (<7%) of the fish biomass is composed of apex predators, predominantly due to the essential absence of sharks from these reefs. Coral cover across these islands averages 26.6%, with fleshy macroalgae and turf algae covering most of the remaining benthos. Coral cover was not correlated with the biomass of any fish groups, failing to provide a clear link between fish activities (e.g., herbivory) and the health and persistence of corals. However, there was a strong, positive correlation between macroalgal cover and herbivorous fish biomass. This result is in contrast to previously published reports and may identify a disparity between correlational studies conducted within islands (or nearby islands) versus studies comparing results from across islands. These data provide insights into the structure of reef communities in the southern Caribbean Sea.
This study sought to quantify the potential effects of changes in Caribbean reef fish populations on recreational divers' consumer surplus. Over five hundred tourist SCUBA divers were interviewed at seven sites across three Caribbean countries representing a diversity of individuals within the Caribbean dive market. A choice experi- ment was used to assess willingness to pay as a function of the abundance and size of reef fishes, the presence of fishing activity/gear, and dive price. Despite some preference heterogeneity both between and within sites, the results indicate that future declines in the abundance of reef fishes, and particularly in the number of large fishes observed on recreational dives, will result in significant reductions in diver consumer surplus. On the other hand, improvements in fish populations and reduced fishing gear encounters are likely to result in signif- icant economic gains. These results can be used to justify investment in pre-emptive management strategies targeted at improving reef fish stocks (namely reducing unsustainable fishing activities and land-based reef im- pacts), managing conflicting uses, as well as to indicate a possible source of financing for such conservation activities.
The REEF/TNC Fish Survey Project is a volunteer fish monitoring program developed by the Reef Environmental Education Foundation (REEF) with support from The Nature Conservancy (TNC). REEF volunteers collect fish distribution and log scale abundance data for the project using a standardized visual method. These data are housed in a publicly accessible database on REEF’s Website (http://www.reef.org). To date, the REEF database contains over 19,000 surveys from approximately 1,800 sites in the tropical western Atlantic region. The standardized census method provides a consistency in data collection applied over a wide geographic range. Such a database represents a valuable tool for marine resource managers. REEF data are currently being used by a number of marine parks and resource agencies for assessment and long- term monitoring, including the Bonaire Marine Park (BMP; Bonaire, Netherlands Antilles). Between December 1993 and July 1999, approximately 2,000 fish surveys have been completed by REEF volunteers on the reefs of Bonaire and Klein Bonaire. From these data, a total of 362 species were reported from 77 sites surveyed, making Bonaire one of the most species rich locations in REEF's database. Similarity and ordination analysis on a sub-set of sites indicated that fish assemblages on Klein Bonaire were distinct from those on Bonaire. Sites within the two Bonaire research reserves appeared distinct from other Bonaire sites. This paper provides the most comprehensive species list to date for the BMP. In addition, this established database will act as a baseline against which future change can be assessed.