Fish

Temporal dynamics of fish assemblage on artificial reefs with varying distances from a coral reef ecosystem

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.

Date
2016
Data type
Other resources
Theme
Research and monitoring
Geographic location
Bonaire
Author

Research Note: Fish Records from the Saba Bank Commercial Fishery

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.

Date
2007
Data type
Other resources
Theme
Research and monitoring
Geographic location
Saba bank
Author

High prevalence of dermal parasites among coral reef fishes of Curaçao

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. 

Date
2015
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Curacao

Life in the unthinking depths: energetic constraints on encephalization in marine fishes

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.

 

Date
2015
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Curacao

‘Quick scan’ to assess the prevalence of dermal parasites among coral reef fishes of Bonaire.

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”. 

 

Date
2015
Data type
Research report
Theme
Research and monitoring
Report number
C055/15
Geographic location
Bonaire
Image

Fishbase

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).

Date
2015
Data type
Portal
Theme
Research and monitoring
Tags
Geographic location
Aruba
Bonaire
Curacao
Saba
Saba bank
St. Eustatius
St. Maarten
Image
Fishbase

Preliminary list of fishes from the Smithsonian Tropical Research Institute expedition to Curaçao with comparison to previously formulated lists

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.

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

Fish assemblages on the Saba bank (Dutch Caribbean): the effect of habitat, depth and fisheries

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.

Date
2014
Data type
Research report
Theme
Research and monitoring
Report number
T 1940 THESIS
Geographic location
Saba bank
Author

Saba Bank Research Expedition 2013 - Progress Report

The Saba Bank is the largest submerged carbonate platform of 2,200 km2 in the Caribbean Sea, which lies partially within the Exclusive Economic Zone of the Netherlands and partially within the territorial waters of Saba and St. Eustatius. The Saba Bank houses an expansive coral reef ecosystem with a rich diversity of species and as such is also an important source of commercial fish for the nearby islands.

The Saba Bank furthermore forms the largest protected area of the Kingdom of the Netherlands, after the Dutch part of the Wadden Sea in Europe. It was declared a protected area by the Dutch Government in 2010 and has been registered as such in the Specially Protected Areas and Wildlife (SPAW) protocol of the Cartagena Convention for the Protection and Development of the Marine Environment of the Wider Caribbean. In 2012 it was internationally declared a Particularly Sensitive Sea Area (PSSA) by the International Maritime Organization (IMO) and an Ecological or Biological Significant Area (EBSA) by the Convention on Biological Diversity (CBD). As there are no large land masses nearby, the Saba Bank can be considered as relatively pristine and remote from human influences. Anthropogenic threats such as fisheries and environmental threats such as climate change, sea surface temperature increase and acidification, however, also threaten the Bank’s coral reefs.

As part of the Saba Bank research program 2011-2016, commissioned by the Dutch Ministry of Economic Affairs (EZ), expeditions to the Saba Bank were conducted in October 2011 and from 19 to 26 October 2013. The Saba Bank research program aims to obtain information on the biodiversity, ecological functioning and carrying capacity for commercial fisheries to facilitate sustainable management of the area. The expedition was funded by the Dutch Ministry of Economic Affairs and the World Wildlife Fund in the Netherlands.

The primary objectives of the 2011 and 2013 research expeditions were to collect data on benthic and reef fish communities, and on sponges and nutritional sources of the sponge community. Studies added to the 2013 expedition were research into the structural complexity of the reef; coral-algal interactions; and connectivity between populations. An international, multidisciplinary team of marine biologists investigated the coral reef structure as well as the spatial variation in species assemblages and population genetic connectivity of corals, algae, fish and sponges during eleven SCUBA dives at 20-30m depth.

During the expedition thirty-three 50m long transects resulted in more than 2000 images of the reef, and over 5000 fish counts of almost 100 fish species. A preliminary comparison with the data from 2011 gives the impression of a reduction in snappers, groupers and grunts, while there were noticeably more sharks. There were fewer algae on the Saba Bank than in 2011, possibly indicating a healthier reef, although there appeared to be a gradient of increasing algal cover towards the island of Saba. It seems unlikely that this is related to anthropogenic activities on the island, but more likely to natural causes.

An overview of collected data and preliminary results is given in this progress report. Further comparative analysis between the data collected in the 2011 and 2013 and further analysis between research components, e.g. between algal biomass, herbivorous fish biomass and nutrient levels, will be performed in 2014. This may give more information on the potential causes of the observed south-north algal gradient.

The expedition elicited large public interest and media coverage in both Dutch and Caribbean media (details provided in Appendix F). The work of the researchers, both above and under water, was also recorded on film as part of the documentary series Marine Life for Discovery Channel.

Date
2014
Data type
Research report
Theme
Research and monitoring
Report number
C086/14
Geographic location
Saba bank