Reef fish

Video (in Portuguese)

https://repositorio.ufsc.br/handle/123456789/251105

Abstract

Os recifes são ambientes muito importantes para os oceanos e os peixes que vivem neles são partes importantes na modulação desses ambientes. Neste estudo buscamos entender sobre como e quanto os peixes exercem uma pressão seletiva no ambiente recifal através da sua alimentação. Utiliamos o método de filmagem remota para comparar 3 ilhas (Bali- Indonésia; Curaçao - Caribe e Atol das Rocas - Brasil) e entender como os peixes exploram e repartem o ambiente e se nesses 3 locais com um gradiente de riqueza de espécie, sendo Bali o local mais rico e Atol o menos rico. Para isto contamos o número de mordidas que foram gravada, além de separar as espécies por grupo trófico-funcional para entender a exploração exercida por eles.

Reefs are very important environments for the oceans and the fish that live in them are important parts in modulating these environments. In this study we seek to understand how and how much fish exert selective pressure on the reef environment through their diet. We used the remote filming method to compare 3 islands (Bali - Indonesia; Curaçao - Caribbean and Atol das Rocas - Brazil) and understand how fish explore and share the environment and whether in these 3 places with a gradient of species richness, Bali being the richest place and Atoll the least rich. To do this, we counted the number of bites that were recorded, in addition to separating the species by trophic-functional group to understand the exploitation carried out by them.

Dutch below

A collaborative study, led by the University of Texas at Austin, deployed 102 specialized fish monitoring structures across six locations, including the deep reefs of Curacao.  The goal of this study was to identify a standardized simple and effective way to survey small, bottom-dwelling fish populations.

From shallow tide pools to the deep sea, unique evolutionary traits allow fish to occupy every corner of the ocean. Historically, fish populations have been tracked using visual surveys, which can often overlook small or bottom-associated (cryptobenthic) species. A collaborative study, led by the University of Texas at Austin, explored a new technique to quantify these difficult to find species by utilizing a Fish-specific Autonomous Reef Monitoring Structures (FARMS).

FARMS

These FARMS are specifically created using easily accessible and affordable materials. Through a combination of stacked PVC pipes and mesh baskets, FARMS can be deployed in a wide variety of locations to investigate these cryptobenthic populations.  Although FARMS may not fully replicate the surrounding environment, especially in habitats with no solid structures, this study did find these structures to be an efficient technique for sampling local diversity, capturing a higher number of species per unit area compared to other methods.

Curacao

During this study, FARMS were deployed across six locations (Hawaii, Texas, Panama, Saudi Arabia, Brazil and Curacao). The FARMS deployed off Curacao were used to explore deeper areas of reef, placed at 60m, 146m and 223m depth. Due to the limitations for SCUBA-based research, deep reefs are some of the least explored ecosystems and the vast majority of deep reef research has relied on visual counts. Accordingly, one of the FARMS captured a species of goby (Psilotris laurae) which has never before been documented on Curacao. This highlights the ability of these systems to provide a new, improved way of sampling populations, particularly in deep or hard to reach locations.

Fish species found using FARMS. Photo credit: Simon Brandl

Impacts

Overall, FARMS are considered a simple, standardized, and cost-effective technique for studying cryptobenthic fish communities in habitats where other sampling methods are considered impractical or restricted. The study highlighted the potential of FARMS for exploring under sampled habitats, such as deep reefs, where they could contribute to the discovery of new species and enhance our understanding of cryptobenthic fish diversity and distribution patterns.

DCNA

The Dutch Caribbean Nature Alliance (DCNA) supports science communication and outreach in the Dutch Caribbean region by making nature-related scientific information more widely available through amongst others the Dutch Caribbean Biodiversity Database, DCNA’s news platform BioNews and the press. This article contains the results from several scientific studies but the studies themselves are not DCNA studies. No rights can be derived from the content. DCNA is not liable for the content and the (in) direct impacts resulting from publishing this article.

Een collaboratieve studie, geleid door de University of Texas in Austin, heeft 102 gespecialiseerde structuren voor het monitoren van vissen ingezet op zes locaties, waaronder de diepe riffen van Curaçao. Het doel van deze studie was om een gestandaardiseerde, eenvoudige en effectieve manier te vinden om kleine, op de bodem levende vispopulaties te onderzoeken.

Van ondiepe getijdenpoelen tot de diepzee, dankzij unieke evolutionaire eigenschappen kunnen vissen elke hoek van de oceaan bezetten. Historisch gezien zijn vispopulaties gevolgd met behulp van visuele onderzoeken, die vaak kleine of met de bodem geassocieerde (cryptobenthische) soorten over het hoofd kunnen zien. Een gezamenlijke studie, geleid door de University of Texas in Austin, onderzocht een nieuwe techniek om deze moeilijk te vinden soorten te kwantificeren door gebruik te maken van een visspecifieke autonome rif monitor structuur (FARMS).

FARMS

Deze FARMS zijn speciaal gemaakt met behulp van gemakkelijk toegankelijke en betaalbare materialen. Door een combinatie van gestapelde PVC-buizen en gaasmanden kan FARMS op een groot aantal verschillende locaties worden ingezet om deze cryptobenthische populaties te onderzoeken. Hoewel FARMS de omgeving mogelijk niet volledig nabootsen, vooral in habitats zonder vaste structuren, vond deze studie deze structuren een efficiënte techniek voor het bemonsteren van lokale diversiteit, waarbij een groter aantal soorten per oppervlakte-eenheid werd gevangen in vergelijking met andere methoden.

Curaçao

Tijdens dit onderzoek werden FARMS ingezet op zes locaties (Hawaii, Texas, Panama, Saoedi-Arabië, Brazilië en Curaçao). De FARMS die buiten Curaçao werden ingezet, werden gebruikt om diepere delen van het rif te verkennen, geplaatst op 60 meter, 146 meter en 223 meter diepte. Vanwege de beperkingen van SCUBA-gebaseerd onderzoek, zijn diepe riffen een van de minst onderzochte ecosystemen en de overgrote meerderheid van diep rifonderzoek is gebaseerd op visuele tellingen. Niet geheel onverwachts ving een van de FARMS dan ook een soort grondel (Psilotris laurae) die nog nooit eerder op Curaçao was gedocumenteerd. Dit benadrukt de capaciteit van deze systemen om een nieuwe, verbeterde manier te bieden om populaties te bemonsteren, met name op diepe of moeilijk bereikbare locaties.

Vissoorten gevonden met FARMS. Foto: Simon Brandl

Effecten

Over het algemeen worden FARMS beschouwd als een eenvoudige, gestandaardiseerde en kosteneffectieve techniek voor het bestuderen van cryptobenthische visgemeenschappen in habitats waar andere bemonsteringsmethoden als onpraktisch of beperkt worden beschouwd. De studie benadrukte het potentieel van FARMS voor het verkennen van onder bemonsterde habitats, zoals diepe riffen, waar ze kunnen bijdragen aan de ontdekking van nieuwe soorten en ons begrip van de diversiteit en verspreidingspatronen van cryptobenthische vissen kunnen vergroten.

DCNA

De Dutch Caribbean Nature Alliance (DCNA) ondersteunt wetenschapscommunicatie en outreach in de Nederlandse Caribische regio door natuurgerelateerde wetenschappelijke informatie breder beschikbaar te maken via onder meer de Dutch Caribbean Biodiversity Database, DCNA’s nieuwsplatform BioNews en de pers. Dit artikel bevat de resultaten van verschillende wetenschappelijke onderzoeken, maar de onderzoeken zelf zijn geen DCNA-onderzoeken. Aan de inhoud kunnen geen rechten worden ontleend. DCNA is niet aansprakelijk voor de inhoud en de (in)directe gevolgen die voortvloeien uit het publiceren van dit artikel.

Published in BioNews 67

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 student research was retrieved from Physis: Journal of Marine Science II (Fall 2007)19: 32-36 from CIEE Bonaire.

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.

This student research was retrieved from Physis: Journal of Marine Science II (Fall 2007)19: 15-19 from CIEE Bonaire.

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.

This student research was retrieved from Physis: Journal of Marine Science X (Fall 2011)19: 46-52 from CIEE Bonaire.

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.

This student research was retrieved from Physis: Journal of Marine Science XII (Fall 2012)19: 64-72 from CIEE Bonaire.

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.