Fish

Juvenile french angelfish, Pomacanthus paru, are known to be cleaner fish. Cleaning is an interesting mutualistic behavior between 2 individuals where 1 species, the cleaner, removes parasites off a client. In Bonaire however, little has been studied on P. paru specifically. A study of cleaner fish in general was performed in 1998 in Bonaire, but there was only 1 recorded incidence of P. paru cleaning 2 individuals. Juvenile french angels have however, been shown to be a significant part of the cleaner community in Brazil. Data was collected 27 times, for a total of 9.6hrs of direct observation of juvenile french angelfish. The angels spent 19.5% of their time, 1.87hrs, collectively cleaning. Twenty four species were seen cleaned and another 4 species were spotted being serviced while not conducting research. A total of 168 individuals came to be cleaned over 186 separate cleaning sessions. When compared to other studies, these results show that at this study location in Bonaire, juvenile P. paru are an intricate part of the cleaning community.

This student research was retrieved from Physis: Journal of Marine Science III (Spring 2008)19: 19-23 from CIEE Bonaire.

Spinyhead blennies (Acanthemblemaria spinosa) and secretary blennies (Acanthemblemaria maria) are abundant, tube-dwelling fishes on the reefs of Bonaire, Netherlands Antilles. In other areas of the Caribbean A. maria are relatively rare and although habitat partitioning has been described for A. spinosa, little is known concerning habitat partitioning in A. maria or about the competitive interactions between the two species. This study determines the species distribution and density of A. spinosa and A. maria in the nearshore reefs of Bonaire and documents the competitive interactions between the 2 species using a manipulative experiment. The distribution of A. spinosa and A. maria was determined using transects on the reef slope and by observations of patch reefs on the reef flat. Experimental condos were constructed and placed on sand flats at 6 m depth, where there is overlap of the ranges. Five individuals from both species were captured and placed on a condo to observe the competitive interactions between A. spinosa and A. maria. A. maria are more abundant on the reef flat while A. spinosa are primarily found on the reef slope (> 6 m). In the condo experiments A. maria were dominant over A. spinosa. It is hypothesized that the slightly larger size and increased competitive nature due to higher densities of A. maria give them an advantage over A. spinosa. This study supports previous findings on the distribution of A. maria and A. spinosa on coral reefs and documents competitive dominance of A. maria over A. spinosa.

This student research was retrieved from Physis: Journal of Marine Science IV (Fall 2008)19: 30-34 from CIEE Bonaire.

Habitat selection is critical to the development, growth and reproductive success for most marine animals. Organisms select habitat based on food availability, as in gulls of the North Sea, complexity of structure, as in juvenile fish of seagrass beds, or a combination of both factors as in marine snails of the rocky intertidal zone. Mangrove forests are known to be important habitat and nursery grounds for many endangered and/or economically important species of fish. These habitats are currently under threat by coastal development and overexploitation, therefore, scientifically supported restoration efforts are currently being pursued. The mangroves of Bonaire are threatened by development, causing hypersaline conditions and change in water flow. In this study food availability and composition as well as the structural complexity of the mangrove prop root system were assessed as possible attractants to juvenile fish. Snorkeling observations along permanent transects of the fishes in and amongst the prop roots as well as the algae and invertebrates living on the prop roots were conducted to establish a baseline understanding of the mangrove community (consumers and prey). In order to assess the impacts of consumers on prop root epibiota, consumers were excluded from prop roots using plastic mesh and the regrowth of preferred food species was monitored. The caging experiment showed evidence of the impacts of herbivores in the mangroves as green algae growth increased significantly in their absence and growth of red algae decreased. Artificial mangrove units (AMUs), modeled after prop roots, were also constructed for this study to test the attractiveness of structural complexity to resident fish. Comparisons between the behavior of the fish community of mangrove prop roots and that of AMUs indicated that there is no distinguishable preference between predators and consumers for structurally complex habitat, but that both prefer more complex habitat over simple structure. The data collected concerning preferred food and habitat structural complexity could be used in restoration projects.

This student research was retrieved from Physis: Journal of Marine Science V (Spring 2009)19: 20-26 from CIEE Bonaire.

Biodiversity of coral reef fish species is often related to the structural complexity and diversity of their habitats. This study explores the relationship between fish species richness, habitat diversity (substrate diversity) and habitat complexity (rugosity). Habitat diversity and topographic measures were used to predict reef fish diversity. It was hypothesized that high fish species diversity would show a positive correlation with greater habitat structure, which includes habitat diversity and topographic complexity. Fish species richness was determined at six dive sites in Bonaire, N.A. (Karpata, Andrea II, Cliff, Windsock, Angel City, and Red Slave) using data from 20 randomly chosen expert-level surveys provided by Reef Educational Environmental Foundation (REEF) for 2004 – 2009. Preliminary analysis of REEF data was used to select sites with high and relatively low fish species richness to make comparisons with the habitat structural complexity measurements (substrate diversity and rugosity). Substrate diversity and habitat complexity were measured using a 10 m transect randomly placed at 4 depths (2, 6, 12, and 18 m) at each site. Substrate diversity was determined by measuring the percent cover of the different substrates and then using the Shannon Diversity Index to determine H’. The rugosity of the sample area was measured by fitting a lead line to the reef at each of the determined depths. Overall results suggested that topographical complexity (rugosity) was not related to high fish species richness at dive sites on Bonaire. There was a weak positive correlation between H’ and fish species richness on the reef slope and a weak negative relationship between H’ and fish species richness on the reef flat. The results provide evidence that there are more factors to consider when explaining fish species richness on coral reefs than the structural complexity of the habitat at the scale of this study.

This student research was retrieved from Physis: Journal of Marine Science VI (Fall 2009)19: 66-72 from CIEE Bonaire.

Worldwide, fisheries produce ~27 million tons of by-catch yr -1 . By-catch is defined as unwanted fish that are accidentally caught, or discarded carcasses of target species. In Bonaire, N.A., by-catch is produced on a relatively small scale, by artisanal fishermen cleaning fish that they caught and discarding the remains back into the ocean. This study examines the feeding behaviors of fish in Bonaire and the effect fishermen’s by-catch has on these behaviors, and also investigates the potential for fish to learn about sites of by-catch input. This study was performed in two parts, the first assesed the effects of established by-catch sites, while the second part focused on learning behaviors of fish. Bites per minute, time of arrival to the food source and fish population data was collected at sites along Kaya Playa Lechi where fishermen were present daily. The same data was collected 30 m away from the fishermen at simulated by-catch sites, as well as at control sites where no by-catch was present. In part II, the discarding of fish was simulated at sites that do not receive it on a normal basis, to obtain observations on fish reactions to a new food source. It was found that densities and biodiversity were significantly greater at by-catch treatments vs. control treatments for part I. Bites min-1 was greatest when by-catch was present and the time of arrival data showed that the greatest proportion of fish arriving for the fishermen’s by-catch was within the first 15 s. For part II, densities and biodiversity were greater at control treatments than at simulated by-catch treatments. Bites min-1 was greater at simulation treatments, and there was a decrease in the time of arrival over the three day observation period. This data shows that relatively greater fish densities were seen at sites of food input, that fish were more aggressive when by-catch was present, and that fish can learn that to respond to sites with a consistent input of by-catch.

This student research was retrieved from Physis: Journal of Marine Science VII (Spring 2010)19: 21-26 from CIEE Bonaire.

Coral reefs have existed for thousands of years and are currently subjected to many threats. Coral disease is of particular concern because of its increasing prevalence; because they reduce coral cover, diseases are likely to affect fish assemblages. This study looks at the factors of coral disease and fish species richness on Bonaire, Dutch Caribbean. The study tests the hypotheses that (1) the amount of coral disease present in Bonaire has increased since 2007 and (2) the species richness of fish assemblages decreases with increasing presence of coral disease. Coral disease prevalence and live coral cover was assessed using an adaptation of the AGRRA benthic methodology by laying 10 m transects at depths of 10 and 12.5 m at Cliff and Windsock, areas that are closed and opened to fishing respectively. In addition, fish species richness was assessed using the roving diver technique by REEF. There was a significant difference between coral disease, as well as live coral cover, between sites and years. Species richness had a significant weak but not significant correlation with coral disease and live coral cover. However, no significant difference was found in the fish species richness between sites or between years.

This student research was retrieved from Physis: Journal of Marine Science X (Fall 2011)19: 40-46 from CIEE Bonaire.

Coral reefs around the world are experiencing high levels of degradation due to temperature changes, increased nutrients and destructive fishing techniques. For example, where there were once large thickets of the branching coral Acropora cervicornis along the coasts of Bonaire, Dutch Caribbean, there is now sand and dead coral. Loss of an entire highly complex habitat has likely altered the local reef fish community. Artificial reefs have been used in the past to test hypotheses about structural complexity and its effects on reef fish communities. However, no studies have sought to discover if artificial reef structures modeled after A. cervicornis would support reef fishes found in the natural branching coral colonies by mimicking the structural complexity provided by the coral. To answer this question, four patches of artificial A. cervicornis were constructed and placed near the reef crest on the leeward side of Bonaire, Dutch Caribbean. Natural thickets of A. cervicornis were used to compare differences in fish species richness, diversity and density. Artificial reef structures were found to support higher diversity but lower abundance of fish. There was no significant difference in species richness between the natural and artificial reef stands. Overall, the artificial reef structures were able to provide some shelter to certain fish species, but were not able to support the fish community that is supported by natural stands of A. cervicornis.

This student research was retrieved from Physis: Journal of Marine Science X (Fall 2011)19: 21-27 from CIEE Bonaire.

Disease in the ocean is difficult to study because of the logistics involved in conducting marine research. This in turn has resulted in a lack of recognition when outbreaks do occur. Most diseases do not manifest themselves in an organism unless the individual is subject to stress that weakens its ability to fight disease. In recent years, anthropogenic stressors have increased in the world’s oceans; something thought to be increasing the incidence of disease. Recently, ocean surgeonfish, Acanthurus bahianus, in Bonaire, Curacao, and Turks and Caicos, have been observed with black spots on their bodies. There has not been any research on the subject and the causative agent has not been identified. The purpose of this study was to develop a basic understanding of the ocean surgeonfish with black spots. Using timed swims and observations, data on frequency of disease at depths, flash rate, bite rate, and percentage of time spent feeding were collected. There was a significant difference in the frequency of individuals across depth. In addition, there was a positive correlation between number of spots and percent of time spent feeding. However, there was no relationship found between number of spots and feeding rate and flash rate. This disease is affecting 89% of ocean surgeonfish. The implications of this disease are important to understand because ocean surgeonfish play a strong ecological role as herbivores in coral reef ecosystem.

This student research was retrieved from Physis: Journal of Marine Science XI (Fall 2012)19: 64-69 from CIEE Bonaire.

Sergeant majors (Abudefduf saxatilis) engage in male-dominated reproduction: males establish territories, females are courted, mate with the male and then depart – leaving protection of the eggs to the male. A. saxatilis prefer smooth, artificial substrate for egg laying; in Bonaire, Dutch Caribbean, they tend to mate on large, concrete mooring blocks which have surfaces of varying degrees of exposure to the water column. Preferred nesting locations were expected to be those offering the least exposure, as broods would be shielded from predators and guarding males would expend minimal energy. The number of threats, chases and feeds in a 5 min interval were recorded as an indicator of energy expenditure and consumption. The length of the fish and size of corresponding egg brood were measured as indicators of mating potential. The number of threats, chases and feeds did not differ significantly between degrees of exposure, but threats and chases differed between sites, being greatest at the site closest to the reef, possibly indicating that exposure does not play a role in energy expenditure and therefore may not affect preferred mating locations. However, larger fish and larger broods were observed on the most protected sides of the mooring blocks offering some support to the notion that A. saxatilis prefer to nest in more protected locations. An increase in the number of artificial structures could lead to an A. saxatilis population rise

This student research was retrieved from Physis: Journal of Marine Science XI (Fall 2012)19: 58-63 from CIEE Bonaire.

SCUBA diving on coral reefs is a beneficial economic option for small tropical islands, that can have a lower impact on the environment than alternative options, such as the fishing industry. However, diving can also have a negative impact, when divers physically damage the reefs. The effects of diving on reef fish populations have received little study, though alteration of fish distribution or recruitment in areas with high levels of diving is likely. The purpose of this study was to evaluate the impact of diving on coral and fish communities in Bonaire, Dutch Caribbean. Coral and fish communities at six sites adjacent to a popular dive site were studied. Sites studied included two sites immediately adjacent to the entry where most divers pass, 2 sites (120 m from entry) with intermediate levels of diving and 2 sites (240 m from entry) representing less dived sites. Benthic video transects were conducted at two depths (8-10 m, 15 m), recording coral cover and abundance of Atlantic Gulf Rapid Reef Assessment fish species. Coral cover increased with increasing distance to the north of the site, peaking at 31.2%. Coral cover decreased south of the site, which could be attributed to anthropogenic influences occurring due to southern sites proximity to a main population center. A known relationship between Agaricia spp. and Montastrea annularis complex was observed, with the first increasing at intermediately disturbed site, and the latter decreasing at the same sites. All other factors varied greatly across sites and could not be associated with changes in diver intensity; however they could be associated with anthropogenic pressures. Overall, this study did not show significant diver impact, though it displayed negative trends in relation to anthropogenic factors.

This student research was retrieved from Physis: Journal of Marine Science XI (Fall 2012)19: 21-28 from CIEE Bonaire.