Fish

The invasion of Pterois volitans (lionfish) is a serious concern for Caribbean coral reef health. The morphology and behavior of lionfish is novel to the reef in Bonaire, which allows lionfish to take advantage of resources at the expense of native reef fish. Cephalopholis cruentata (graysby) is a native grouper on a similar trophic level as lionfish. Other groupers show congeneric aggression, but documentation of graysby behavior is scarce. This study observed graysby behavior and investigated whether graysbys recognize lionfish as competitors. A model-bottle experiment was used to present lionfish to graysbys. Graysby responses, aggressive, neutral, and submissive, were observed. Behavior was quantified using a reactive index. No significant difference in the frequency distribution of behavior types was observed between treatments. A moderate correlation was observed between graysby size and reactive index, suggesting that graysby reactions may be size-dependent. Future studies should consider size when analyzing graysby behavior towards other species, native or invasive.

This student research was retrieved from Physis: Journal of Marine Science XIX (Spring 2016)19: 85-90 from CIEE Bonaire.

Various marine organisms are known to consciously select specific types of habitat that provide maximum shelter from potential predators. Reef fish such as Haemulon chrysargyreum (smallmouth grunts) are commonly seen congregating in groups around the coral structures in Bonaire. Observing schooling fish can provide pertinent information on the refuge provided by structurally complex and diverse ecosystems. This study assessed the habitat preference of H. chrysargyreum based on species of coral, complexity of sites, and substrate type. Levels of phosphate, nitrate, and ammonia were also analyzed in the areas occupied by shoaling H. chrysargyreum to see if they provide a significant input of nutrients into the coral reef ecosystem. The results of this study demonstrate that H. chrysargyreum prefer areas of medium to high complexity accompanied with a soft substrate (sand, rubble) and an overhanging structure. Nutrient level analysis was inconclusive and, therefore, requires further studies. This research sought to identify certain species of coral and structures that are used by H. chrysargyreum for habitation. Such knowledge can aid conservation efforts by honing in on specific areas that schooling fish utilize for shoaling and feeding. Additionally, data from this study provided preliminary assessment for future studies on the potential nutrient input of H. chrysargyreum to the marine ecosystem.

This student research was retrieved from Physis: Journal of Marine Science XIX (Spring 2016)19: 52-63 from CIEE Bonaire.

Increasing coral reef degradation worldwide is putting more reef fish under stressful circumstances. A possible solution to mitigating the effects of degraded coral reefs is the implementation of artificial reefs. An ongoing question of effective artificial reef utilization asks how far from a natural coral reef ecosystem should these structures be placed. Some studies support the theory that structure isolation attracts larger fish diversity in terms of aggregation and recruitment. In order to test such a hypothesis, four identical artificial structures were deployed next to a coral reef ecosystem in Bonaire, Dutch Caribbean. The impact of position relative to the natural reef was measured, placing two structures close to the reef crest and two 30 meters inshore on the sand flat. After conducting fish counts over a five week period, it was found that artificial reef isolation attracted a higher assemblage of fish, particularly juveniles. Total fish assemblage counted for 1021 fish at the sand flat and 364 fish at the reef crest, with higher fish diversity at the reef crest (1 - 0.77 = 0.23). An interesting temporal trend of French Grunt recruitment was observed at the sand flat. These results demonstrate fish preference for isolated artificial reefs, but the range of species recruited may be limited.

This student research was retrieved from Physis: Journal of Marine Science XIX (Spring 2016)19: 9-15 from CIEE Bonaire.

Recent investigations of Saba Bank, Netherlands Antilles, have sought to develop inventories of marine biodiversity from this large, submerged coral reef atoll. Previous fish species inventories were compiled from underwater visual surveys and poison-based collections (RAP Survey Report, 2006), generating a list of more than 200 taxa (J. Williams, pers. com.). In June of 2007, a six-month port sampling study was initiated to examine landings of the Saba Bank commercial fishery. Port samples of finfish catch and bycatch produced novel fish species records for Saba Bank. These observations make a much needed addition to previous species inventories because they include records for fishes of commercial significance. The purpose of this note is to give a brief written and photographic account of new fish records from the Saba Bank commercial fishery. New species records from underwater surveys and observations from experimental trap fishing of Saba Bank are included as well.

Abstract During expeditions to Curaçao in August and October of 2013, a large number of fish infected with dermal parasites was observed. Infected individuals pre- sented black spots and white blemishes on their skin and fins that were easily observed by divers, and which have been associated with infections by trematodes, turbel- larians, and protozoans (Cryptocaryon). In order to com- pare rates of infection across localities in the Caribbean, we conducted visual censuses of reef fish communities along 40 m2 belt transects in Belize (n = 35), Curaçao (n = 82), and Mexico (n = 80) over a 4-week period. Three affected individuals were recorded in Belize, 75 in Curaçao, and none in Mexico. Approximately 68 % of the infected individuals in Curaçao were surgeonfishes (Acanthuridae). There was no correlation between inci- dence of infection and species abundance (r2 = 0.03), or with functional traits (diet, mobility, schooling behavior, or position in the water column). The causes of the strik- ingly high incidence of dermal parasites in Curaçao and its consequences remain unknown. However, considering that parasites with complex life cycles have several hosts throughout their lives, and that past disease outbreaks have had severe consequences on communities of the Caribbe- an, we caution that coral reef ecosystems of Curaçao should be closely monitored. 

Abstract

Several hypotheses have been proposed to explain the limitation of brain size in vertebrates. Here, we test three hypotheses of brain size evolution using marine teleost fishes: the direct metabolic constraints hypothesis (DMCH), the expensive tissue hypothesis and the temperature-dependent hypothesis. Our analyses indicate that there is a robust positive correlation between encephalization and basal metabolic rate (BMR) that spans the full range of depths occupied by teleosts from the epipelagic (< 200 m), mesope- lagic (200–1000 m) and bathypelagic (> 4000 m). Our results disentangle the effects of temperature and metabolic rate on teleost brain size evolution, supporting the DMCH. Our results agree with previous findings that teleost brain size decreases with depth; however, we also recover a negative corre- lation between trophic level and encephalization within the mesopelagic zone, a result that runs counter to the expectations of the expensive tissue hypothesis. We hypothesize that mesopelagic fishes at lower trophic levels may be investing more in neural tissue related to the detection of small prey items in a low-light environment. We recommend that comparative encephalization  studies control for BMR in addition to controlling for body size and phylogeny.

In the past, diseases and infections have had dramatic impacts on Caribbean coral reef ecosystems (e.g. white band disease in corals (Pantos and Bythell, 2006); mass mortality of the sea urchin Diadema (Lessions, 2005)). Regular monitoring of reef organisms for signs of disease and infections may be important as an “early warning system” to possibly prevent devastating outbreaks. 
In September 2013 an unusual number of reef fish species (e.g. Scaridae (Fig. 1.1 , Acanthuridae and Pomacanthidae) infected with dermal parasites were observed during a dive at Salt Pier (M. de Graaf, pers. obs.). In September 2014 one princess parrotfish infected with dermal parasites was dissected and internal and external samples were send to the Central Veterinairy Institute (CVO) in Lelystad (Netherlands) for further histopathological examination. According to CVO the parrotfish suffered from a microspore parasitic infection of the skin, muscles and digestive tract. The cysts caused fibrotic abscesses and necrosis on the fins.

Similar dermal parasites were observed in a recent survey of coral reef fishes on Curaçao and the observed external blemishes were associated with infections by trematodes (digenean metacercaria), turbellarians and protozoans (Cryptocaryon) (Bernal et al., 2015). Bernal et al. (2015) reported that infection rates of coral reef fish on Curacao were almost ten times higher compared to infection rates of coral reef fish surveyed in Mexico and Belize. To date, only anecdotal observations exist of parasite infections on coral reef fish on Bonaire but no quantitative assessment of the prevalence of dermal parasites is available. 
The objective of the Helpdeskvraag was to:
1) conduct a “quick scan” to determine the current prevalence of dermal parasites among the coral reef fish of Bonaire, and

2) advise EZ on possible consequences and future actions depending on the outcome of the “quick scan”. 

FishBase is a global species database of fish species. FishBase provides comprehensive species data, including information on taxonomy, geographical distribution, biometrics and morphology, behaviour and habitats, ecology and population dynamics as well as reproductive, metabolic and genetic data. There is access to various tools (wikipedia 'fishbase' , retrieved 24 april 2015).

In 2005, the Smithsonian Tropical Research Institute sponsored a collecting trip to Curaçao and Klien Curaçao , as part of a grant to Ross Robertson, to document the fishes of the greater Caribbean region. The Curaçao Sea Aquarium provided support and accommodations for the research team. Collections were made at 29 stations between 2 January and 13 January 2005. Most of the collections were made using rotenone, which is the only effective method of collecting cryptic fishes. A total of 6,114 specimens of 119 taxa were collected. Along with those documented by Metzelaar (1919), FishBase, and several web-based museum collections, we present our findings from Curaçao to document a preliminary list of fishes from that region.

Many environmental variables may influence fish assemblage structures in terms of abundance, biomass and mean size. The aim of this study is to provide a baseline survey on reef fish assemblages and shark presence covering the whole Saba bank (Dutch Caribbean). Hereby determining the influence of habitat, depth and fishing pressure on the structure of reef fish assemblages and shark presence. Baited Remote Underwater Video (BRUV) survey was used to describe reef fish assemblage structures on the Saba bank. Between 2012-2014, a total of 165 60 min BRUV deployments were conducted on locations varying in habitat complexity (0-4, Polunin and Roberts, 1993), depth (15-40m) and fisheries. The eleven most abundant fish species observed on the Saba bank represented eight families and accounted for nearly 50% of the total number of individual fish observed. Labridae was the most abundant fish family observed with a relative abundance of 22%. Most abundant fish species by number of individuals were Thalassoma bifasciatum (N=849 (9.8%)) Stegastus partitus (N=725 (8.4%)) and Acanthurus bahianus (N=430 (5.0%)).

Habitat complexity was positively correlated with species richness (Nsp), fish abundance (MaxN), and mean biomass, and negatively correlated with mean fish length. Strongly developed vertical relief habitats were found to support high numbers of fish species (N=19.1±0.6SE) of relatively low mean lengths (22.4cm±0.3SE), whereas less complex habitats were characterized by low numbers of species (N=8.3±0.8SE) with relatively high mean lengths (24.6cm ±0.81SE). Depth was negatively correlated with Nsp, MaxN and mean biomass and positively correlated with mean fish length. These relationships were all according to expectations based on earlier studies.

A minor part of the variability in the structure of reef fish assemblages was explained by differences in fisheries activity, indicating that no clear fisheries effect was observed in fish assemblages in this study. Furthermore, no significant differences in average size of target species were observed between areas with different fishing pressure. However, the general absence of piscivores such as large snappers and groupers was an indication of the indelible effects of past fisheries on the Saba bank.

A total of 85 shark observations were made with Ginglymostoma cirratum as most abundant species (N=41), followed by Carcharhinus perezii (N=36), Galeocerdo cuvier (N=5) and Carcharhinus limbatus (N=3). Relatively high shark abundances (0.20 sharks hour-1) were observed on the Saba bank compared with other Caribbean regions (The Bahamas: 0.14 sharks hour-1, Belize, 0.17 sharks hour-1). Shark abundance (CPUE) was positively correlated with habitat complexity, whereas depth exerted a negative influence on shark abundances. High shark numbers are a good sign for the health of the Saba Bank ecosystem, since sharks are apex predators, making them a prime indicator for ecosystem health.

Besides ‘traditional’ measures, ecomorphology was presented as an alternative measure in explaining variation in reef fish assemblages. For ecomorphological analysis insight in trophic morphology was obtained by using a Fish Food Model (FFM). The FFM in this study quantitatively related properties of 14 marine food types to morphological characterics of 15 common fish species on the Saba bank and predicted the capacity of utilizing these food types for each species. Strong differences in morphology and little overlap was observed for all different fish species in the FFM-analysis, which was mainly explained by two sets of variables involving predatory and herbivorous lifestyle. By multiplying each species’ capacity of using food types with its abundance an ecomorphological profile of each fish assemblage was calculated. On a functional level reef fish assemblages showed less variability than on species composition level, this possibly is an indication for high levels of robustness in niche differentiation in reef fish communities on the Saba bank.