coral reef

This thesis focuses on understanding the connectivity patterns of coral larvae in the area around Aruba, Bonaire and Curacao and their implications for population dynamics and conservation efforts. The study aims to analyze the spatio-temporal variability of larval dispersal and identify key factors influencing larval connectivity among different reef systems. Connectivity is studied by simulating currents with the 2D version of the Second generation Louvain-la-Neuve Ice-Ocean Model SLIM coupled with a Lagrangian Particle Tracker (LPT). Using a combination of field observations, numerical modeling, and graph theory analysis, we investigated the larval dispersal patterns of four coral species during their respective spawning seasons, the behavior of another species during 6 different months and the connectivity of a fictional species with low mortality rate and no competency loss. The results revealed distinct species-specific differences in larval connectivity, with some species exhibiting higher levels of connectivity within a short distance from their spawning sites, while others displayed broader dispersal capabilities. We also highlighted a strong seasonal variability in the area. Inter-island connectivity have been found for the fictional species and intra-island pattern have been focused on. Furthermore, using other tools from graph theory, the analysis of connectivity matrices and computation of connectivity indicators helped identifying zones of high interest for protection and restoration measures. The research outcomes contribute to the understanding of larval connectivity dynamics in the South-Eastern Caribbean Sea and provide insights for coral reef management and conservation. The results highlight the need for targeted conservation efforts to protect critical larval dispersal pathways and promote genetic exchange among reef systems.

http://hdl.handle.net/2078.1/thesis:40210
 

Coral reefs in the Caribbean are degrading rapidly with a loss of ~50% in just 4 decades. The cause of this degradation is a combination of natural and human impacts (Wilkinson 2000). If present rates of decline continue, researchers project that 60% of Caribbean coral reefs will be lost over the next 30 years. The cumulative impacts from runoff, pol- lution, tourism overuse, destructive fishing and cli- mate change contribute synergistically to these re- gion wide trends. This Assessment finds the same is true for Curacao

The following five indicators were used to assess the health and condition of reef communities at each site: (1) the abundance of reef building organ- isms and their dominant competitors to determine if reefs at a location were growing or declining, (2) the abundance of coral recruits (juvenile corals) to assess the ability of a reef to renew itself, (3) the diversity, abundance, and biomass of all reef as- sociated fishes to assess the state of economically and ecologically important fish species around the island, (4) the abundance of mobile invertebrates such as lobsters and conch (not yet reported in this Assessment), and (5) water measurements to assess water quality for marine life and ocean users. Researchers conducted marine surveys at 148 nearshore sites around Curaçao

Dutch below

Many divers have promoted feeding lionfish to eels and sharks as a way to entice these species to start hunting for these fish independently.  Unfortunately, training these species to look at divers for an easy snack could have some serious unintended consequences. 

The relationship between humans and the marine environment is complex and multifaceted. As our activities expand, we continue to have a significant impact on the behavior of aquatic organisms, including fish. By understanding these interactions, we can better appreciate the delicate balance of marine ecosystems and the importance of responsible recreational practices.

Predatory Fish

(Green moray eel. Photo credit: Rudy Van Geldere)

Predatory fish play a crucial role in maintaining the ecological equilibrium of marine environments. They regulate prey populations and contribute to the overall health of coral reefs and other habitats. Human activities can disrupt their natural feeding patterns, leading to potential consequences for both the predators and their ecosystems. An example of this includes feeding fish.  This not only alters the fishes’ diet but teaches predatory fish to approach humans hoping for a tasty snack.

One prime example of this includes lionfish hunters feeding nurse sharks or eels directly.  Although they have the best intentions, hoping to stimulate these species to eat the lionfish, the end result is that these fish associate divers with an easy meal.  This could mean these fish are more likely to approach divers on the reef. When lionfish hunting, the best practice is to take the lionfish out of the water and dispose of them properly on land.

(Photo credit: Manfred Richter)

Altered Diets

While the practice of feeding fish may seem harmless or even exciting for tourists, it can have detrimental effects on the natural behavior and ecological dynamics on the reef.  This unnaturally brings fish to small areas, making them more vulnerable to other threats (such as fishing) but also alters their diet and pollutes the reef.  Fish that would normally graze algae off the reef may now be tempted to eat whatever food has been placed in the water.

Sustainable Use

Recognizing the potential consequences of human interactions with marine life is essential for promoting responsible behavior and minimizing human impact on the reef.  Promoting sustainable tourism practices that prioritize the preservation of natural environments and wildlife is essential. Encouraging visitors to observe marine life without actively interfering in their feeding behavior can help protect the delicate balance of the ecosystem.

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 through the press. This article is part of a series of articles on ‘Invasive Alien Species in the Dutch Caribbean”. 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.

Veel duikers hebben het voeren van koraalduivels aan murenen en haaien gepromoot als een manier om deze soorten te verleiden zelfstandig op deze vissen te gaan jagen. Helaas kan het trainen van deze soorten om naar duikers te kijken voor een gemakkelijke snack enkele ernstige onbedoelde gevolgen hebben.

De relatie tussen de mens en het mariene milieu is complex en veelzijdig. Naarmate onze activiteiten uitbreiden, blijven we een aanzienlijke invloed uitoefenen op het gedrag van waterorganismen, waaronder vissen. Door deze interacties te begrijpen, kunnen we het delicate evenwicht van mariene ecosystemen en het belang van verantwoorde recreatiepraktijken beter waarderen.

Roofzuchtige vissen

(Groene murene. Photo credit: Rudy Van Geldere)

Roofvissen spelen een cruciale rol bij het handhaven van het ecologisch evenwicht van het mariene milieu. Ze reguleren prooipopulaties en dragen bij aan de algehele gezondheid van koraalriffen en andere leefgebieden. Menselijke activiteiten kunnen hun natuurlijke voedingspatronen verstoren, wat kan leiden tot mogelijke gevolgen voor zowel de roofdieren als hun ecosystemen. Een voorbeeld hiervan is het voeren van vissen. Dit verandert niet alleen het dieet van de vissen, maar leert roofvissen ook om mensen te benaderen in de hoop op een lekker tussendoortje.

Een goed voorbeeld hiervan zijn duikers die op koraalduivels jagen en verpleegsterhaaien of murenen rechtstreeks voeren. Hoewel ze de beste bedoelingen hebben, in de hoop deze soorten te stimuleren om de koraalduivel te eten, is het eindresultaat dat deze vissen duikers associëren met een gemakkelijke maaltijd. Dit zou kunnen betekenen dat deze vissen eerder geneigd zijn om duikers op het rif te benaderen. Bij het jagen op koraalduivels is het het beste om de koraalduivels uit het water te halen en op de juiste manier op het land af te voeren.

(Photo credit: Manfred Richter)

Veranderde diëten

Hoewel het voeren van vissen voor toeristen misschien onschuldig of zelfs opwindend lijkt, kan het nadelige gevolgen hebben voor het natuurlijke gedrag en de ecologische dynamiek op het rif. Dit brengt vissen op onnatuurlijke wijze naar kleine gebieden, waardoor ze kwetsbaarder worden voor andere bedreigingen (zoals vissers), maar verandert ook hun dieet en vervuilt het rif. Vissen die normaal algen van het rif zouden grazen, kunnen nu in de verleiding komen om al het voedsel dat in het water is gekomen  te eten.

Duurzaam gebruik

Het erkennen van de mogelijke gevolgen van menselijke interacties met het zeeleven is essentieel voor het bevorderen van verantwoord gedrag en het minimaliseren van de menselijke impact op het rif. Het bevorderen van duurzame toerismepraktijken die prioriteit geven aan het behoud van natuurlijke omgevingen en dieren in het wild is essentieel. Door bezoekers aan te moedigen het zeeleven te observeren zonder zich actief te bemoeien met hun voedingsgedrag, kan het delicate evenwicht van het ecosysteem worden beschermd.

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 andere de Dutch Caribbean Biodiversity Database, DCNA’s nieuwsplatform BioNews en via de pers. Dit artikel maakt deel uit van een serie artikelen over ‘Invasive Alien Species in the Dutch Caribbean’. 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 indirecte gevolgen die voortvloeien uit het publiceren van dit artikel.

Published in BioNews 66

Coral reefs thrive and provide maximal ecosystem services when they support a multilevel trophic structure and grow in favorable water quality conditions that include high light levels, rapid water flow, and low nutrient levels. Poor water quality and other anthropogenic stressors have caused coral mortality in recent decades, leading to trophic downgrading and the loss of biological complexity on many reefs. Solutions to reverse the causes of trophic downgrading remain elusive, in part because efforts to restore reefs are often attempted in the same diminished conditions that caused coral mortality in the first place. Coral Arks, positively buoyant, midwater structures, are designed to provide improved water quality conditions and supportive cryptic biodiversity for translocated and naturally recruited corals to assemble healthy reef mesocosms for use as longterm research platforms. Autonomous Reef Monitoring Structures (ARMS), passive settlement devices, are used to translocate the cryptic reef biodiversity to the Coral Arks, thereby providing a "boost" to natural recruitment and contributing ecological support to the coral health. We modeled and experimentally tested two designs of Arks to evaluate the drag characteristics of the structures and assess their long-term stability in the midwater based on their response to hydrodynamic forces. We then installed two designs of Arks structures at two Caribbean reef sites and measured several water quality metrics associated with the Arks environment over time. At deployment and 6 months after, the Coral Arks displayed enhanced metrics of reef function, including higher flow, light, and dissolved oxygen, higher survival of translocated corals, and reduced sedimentation and microbialization relative to nearby seafloor sites at the same depth. This method provides researchers with an adaptable, long-term platform for building reef communities where local water quality conditions can be adjusted by altering deployment parameters such as the depth and site.

Dutch, Papiamentu and Papiamento below

Parrotfish are more than just a pretty face. The average parrotfish spends up to 90% of its day cleaning the coral reefs. Their sharp beaks allow them to easily scrape algae off corals and rocks, essential for keeping the reefs healthy and thriving. They are especially important to reef health now given the increase in major stressors such as coral bleaching events and Stony Coral Tissue Loss Disease (SCTLD). Increased protection in the Caribbean region will be considered in the next Conference of parties for the Cartagena Convention (COPS) meeting later this year on Aruba. 

(Princess Parrotfish (Scarus taeniopterus). Photo credit: Marion Haarsma)

Coral reefs provide valuable habitat for fish and other animals. People also benefit from the many ecosystem services coral reefs provide including coastal protection, food and income from tourism and fisheries. In fact, coral reefs are one of the most important sources of income for the Dutch Caribbean islands.  

Important grazers 

(Photo credit: Marion Haarsma)

Herbivores like parrotfish play a critical role in maintaining healthy coral reefs. They help sustain the delicate balance within the reef by grazing on (macro)algae, which are the main competitors for corals for space and light. The average parrotfish spends up to 90% of its day cleaning the reef. Not only does this fish species keep the algae in check, but these herbivores also create new space for baby corals to attach and grow.  

Besides removing macroalgae and promoting coral settlement and growth, parrotfish are also natural bioeroders producing sediment by grazing on rocks, calcareous algae and corals (less than 10% of their food). Hereby they help recycle nutrients and produce “sand” for (eroded) coastal areas.  

The Global Coral Reef Monitoring Network (GCRMN) report entitled “Status and Trends of Caribbean Coral Reefs: 1970-2012″ by Jackson et al. (2014) documented quantitative trends on coral reef health over 43 years in the wider Caribbean. The report identifies that one of the major drivers of coral reef decline in the Caribbean is the overfishing of herbivores, particularly parrotfish. 

Threats 

(Parrotfish on Bonaire’s reef. Photo credit: Steph Wear)

Parrotfish thrive best in healthy coral reefs ecosystems. Therefore, these fish are subjected to the same threats as corals. This includes the negative effects of climate change, ocean acidification, pollution and diseases such as the Stony coral tissue loss disease (SCTLD). In addition, overfishing can quickly wipe out local parrotfish populations. Studies show that reefs are healthier and have a higher recovery resilience capability in locations where parrotfish are protected. This highlights the importance of parrotfish for reefs to be able recover and regrow from these threats. 

Protecting Parrotfish 

In the Dutch Caribbean- on Aruba and Bonaire- there are local rules and regulations to protect all parrotfish. On these islands it is prohibited to catch, kill, wound, or disturb them. Luckily for the other islands in the (Dutch) Caribbean, the Kingdom of Netherlands, along with the Republic of France, have formally submitted a proposal to include all parrotfish in Annex III of the Specially Protected Areas and Wildlife (SPAW) Protocol, a regional agreement for the protection and sustainable use of coastal and marine biodiversity in the Wider Caribbean Region. If approved during the next Conference of parties for the Cartagena Convention (COPS) later this year on Aruba, this measure provides a legal framework for the conservation of the parrotfish to ensure and maintain population at an optimal level in the Wider Caribbean. 

Want to learn more about local parrotfish populations? Check out the following related articles: 

Fish poop: an underappreciated food source for coral reef fishes?, 

Recovery of Orbicella annularis corals from parrotfish predation, 

Parrotfish key to reef survival,

https://www.gefcrew.org/carrcu/SPAWSTAC10/SPAW_STAC10_WG.43-INF.17_EN_Parrotfish_Inclusion.pdf\ 

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. 

Papegaaivissen zijn meer dan alleen een mooi gezicht. De gemiddelde papegaaivis besteedt tot 90% van zijn dag aan het schoonmaken van de koraalriffen. Met hun scherpe bek kunnen ze gemakkelijk algen van koralen en rotsen schrapen, essentieel om de riffen gezond te houden. Vooral nu met grote stressfactoren zoals koraalverbleking en Stoney Coral Tissue Loss Disease (SCTLD), zijn ze belangrijk om koraalriffen te helpen herstellen en opnieuw te laten groeien. Verhoogde bescherming in het Caribisch gebied zal worden overwogen tijdens de volgende Conference of parties for the Cartagena Convention (COPS) die later dit jaar op Aruba plaatsvindt.

(Prinses Papegaaivis (Scarus taeniopterus). Photo credit: Marion Haarsma)

Koraalriffen vormen een waardevol leefgebied voor vissen en andere dieren. Mensen profiteren ook van de vele ecosysteemdiensten die koraalriffen bieden, waaronder kustbescherming, voedsel en inkomsten uit toerisme en visserij. Koraalriffen zijn zelfs een van de belangrijkste bronnen van inkomsten voor de Nederlands Caribische eilanden.

Belangrijke grazers

(Foto: Marion Haarsma)

Herbivoren zoals papegaaivissen spelen een cruciale rol bij het behoud van gezonde koraalriffen. Ze helpen het delicate evenwicht binnen het rif in stand te houden door te grazen op (macro)algen, die de belangrijkste concurrenten zijn voor koralen om ruimte en licht. De gemiddelde papegaaivis besteedt tot 90% van zijn dag aan het schoonmaken van het rif. Deze vissoort houdt niet alleen de algen onder controle, maar deze herbivoren creëren ook nieuwe ruimte voor babykoralen om zich te hechten en te groeien.

Naast het verwijderen van macroalgen en het bevorderen van de vestiging en groei van koralen, zijn papegaaivissen ook natuurlijke bioeroders die sediment produceren door te grazen op rotsen, kalkalgen en koralen (minder dan 10% van hun voedsel). Hiermee helpen ze bij het recyclen van nutriënten en het produceren van “zand” voor (geërodeerde) kustgebieden.

Het rapport van het Global Coral Reef Monitoring Network (GCRMN) getiteld “Status and Trends of Caribbean Coral Reefs: 1970-2012” door Jackson et al. (2014) documenteerde kwantitatieve trends over de gezondheid van koraalriffen gedurende 43 jaar in het bredere Caribisch gebied. Het rapport identificeert dat een van de belangrijkste oorzaken van de achteruitgang van koraalriffen in het Caribisch gebied de overbevissing van herbivoren, met name papegaaivissen, is.

Gevaren

(Papegaaivissen op Bonaire. Foto: Steph Wear)

Papegaaivissen gedijen het best in gezonde ecosystemen van koraalriffen. Daarom worden deze vissen blootgesteld aan dezelfde bedreigingen als koralen. Denk hierbij aan de negatieve effecten van klimaatverandering, verzuring van de oceaan, vervuiling en ziektes zoals de Stoney Coral Tissue Loss Disease (SCTLD). Bovendien kan overbevissing lokale papegaaivispopulaties snel uitroeien. Studies tonen aan dat riffen gezonder zijn en een hoger herstelvermogen hebben op locaties waar papegaaivissen worden beschermd. Dit benadrukt het belang van papegaaivissen voor riffen om te kunnen herstellen en teruggroeien van deze bedreigingen.

Papegaaivissen beschermen

In de Nederlandse Cariben – op Aruba en Bonaire – zijn er lokale regels en voorschriften om alle papegaaivissen te beschermen. Op deze eilanden is het verboden ze te vangen, te doden, te verwonden of te storen. Gelukkig voor de andere eilanden in de (Nederlandse) Cariben heeft het Koninkrijk der Nederlanden, samen met de Republiek Frankrijk, formeel een voorstel ingediend om alle papegaaivissen op te nemen in bijlage III van het Specially Protected Areas and Wildlife (SPAW) Protocol, een regionaal overeenkomst voor de bescherming en het duurzame gebruik van de kust- en mariene biodiversiteit in de ruimere Caribische regio. Indien goedgekeurd tijdens de volgende Conference of parties for the Cartagena Convention (COPS) later dit jaar op Aruba, biedt deze maatregel een wettelijk kader voor de instandhouding van de papegaaivis om de populatie op een optimaal niveau in de wijdere Cariben te verzekeren en te behouden.

Wilt u meer weten over de lokale papegaaivispopulaties? Bekijk de volgende gerelateerde artikelen:

Fish poop: an underappreciated food source for coral reef fishes?,

Recovery of Orbicella annularis corals from parrotfish predation,

Parrotfish key to reef survival,

https://www.gefcrew.org/carrcu/SPAWSTAC10/SPAW_STAC10_WG.43-INF.17_EN_Parrotfish_Inclusion.pdf\

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 indirecte gevolgen die voortvloeien uit het publiceren van dit artikel.

Gutu ta un piská ku ta bal mas ku djis unu ku nèchi kara so. E gutu averahe ta traha 90% di su bida riba tene ref di koral limpi. Ku nan boka skèrpi fásilmente nan ta raspa alga for di koral i baranka, loke ta esensial pa tene e refnan sano i salvo. Espesialmente aworakí ku tin faktornan importante manera evento di blikiamentu di koral i e malesa ‘Stony coral tissue loss disease (SCTLD)’ nan ta importante pa yuda ref di koral pa rekuperá i sigui krese. Ta bai konsiderá e aspekto di alsamentu di protekshon den region di Karibe den e siguiente Konferensia di Partido den e reunion di ‘Cartagena Convention (COPS)’ mas den kurso di e aña akí na Aruba. 

(Foto: Marion Haarsma)

Ref di Koral ta duna habitat importante na piská i otro animal. Hende tambe tin benefisio di e hopi servisionan di e ekosistema ku ref di koral ta krea, inkluso protekshon di kosta, kuminda i entrada for di turismo i peska. En realidat, ref di koral ta un di e fuentenan mas importante di entrada pa e islanan di Hulanda Karibense. 

Komedó di yerba important 

(Foto: Marion Haarsma)

Hèrbivor manera gutu tin un papel importante den mantenshon di ref di koral sano. Nan ta yuda pa mantené e balansa delikado denter di e ref dor di kome e (makro) alga, ku ta e kompetidor mas grandi pa espasio i lus. E gutu averahe ta pasa te ku 90% di su dia hasiendo ref limpi. No solamente e espesie di piská akí ta mantené e alga bou di kontrol, pero e hèrbivornan akí ta krea tambe espasio nobo pa yu di koral por ankra i krese. 

Ademas eliminando makro alga i promoviendo ankramentu i kresementu di koral, gutu ta un outor di eroshon biológiko ku ta produsí sedimento dor di raspa baranka pa kome alga i koral (ménos ku 10% di nan kuminda). Asina nan ta yuda resiklá nutriente i produsí “santu” pa áreanan (ku eroshon) na kosta. 

E rapòrt di ‘Global Coral Reef Monitoring Network (GCRMN)’ titulá “Status and Trends of Caribbean Coral Reefs / Status i Kurso di desaroyo di Ref di Koralnan Karibense: 1970-2012″ pa Jackson et al. (2014) a dokumentá tendensia di desaroyo kuantitativo di salubridat di ref di koral durante 43 aña den e region di Karibe amplio. E rapòrt ta mustra ku un di e faktornan mas grandi di dekadensia di ref di koral den Karibe ta e peska eksesivo di hèrbivor, partikularmente di gutu. 

Menasa 

(Foto: Steph Wear)

Gutu ta prosperá mas tantu den ekosistemanan di ref di koral saludabel. Pa e motibu ei e piská akí tin e mesun enemigunan ku ta krea menasa ku e enemigunnan di koral. Esakinan ta inkluí e efektonan negativo di kambio di klima, oumento di ásido (zür) den osean, polushon i malesa manera e ‘Stony coral tissue loss disease (SCTLD)’. Ademas, peska eksesivo por kaba ku populashonnan lokal di gutu. Investigashonnan ta mustra ku refnan ta mas saludabel i tin un kapasidat di resiliensia mas haltu kaminda ku gutu ta protehá. Esaki ta enfatisá e importansia di gutu pa refnan por rekuperá i krese di nobo despues di e menasanan akí. 

Protekshon di Gutu 

Na Hulanda Karibense – ta na Aruba ku Boneiru – tin lei i regulashon lokal pa protekshon di gutu. Na e islanan akí ta prohibí pa kohe, mata, heridá òf stroba nan. Afortunadamente pa e otro islanan na Karibe (Hulandes), Reino Hulandes, huntu Repúblika di Fransia, a entregá formalmente un proposishon pa inkluí tur gutu den e Anekso III di e protokòl ‘Specially Protected Areas and Wildlife (SPAW) Protocol’, un akuerdo regional pa protekshon i uso duradero di e biodiversidat marino den e Region di Karibe Amplio. Si akordá esaki durante e próksimo konferensia di partido pa e konvenshon ‘Cartagena Convention (COPS) IGM20/COP17’ mas den kurso di e aña akí na Aruba, e medida akí ta krea un kuadro legal pa konservashon di gutu pa sigurá i mantené e populashon di gutu na un nivel optimal den Karibe Amplio. 

Bo ke haña mas konosementu tokante populashonnan lokal di gutu? Chèk e siguiente artíkulonan ku laso: 

Fish poop: an underappreciated food source for coral reef fishes?, 

Recovery of Orbicella annularis corals from parrotfish predation, 

Parrotfish key to reef survival,

https://www.gefcrew.org/carrcu/SPAWSTAC10/SPAW_STAC10_WG.43-INF.17_EN_Parrotfish_Inclusion.pdf\  

DCNA 

Dutch Caribbean Nature Alliance (DCNA) ta sostené komunikashon sientífiko i presentashon na públiko den region Karibe Hulandes dor di hasi informashon sientífiko relashoná ku naturalesa mas ampliamente disponibel pa medio di entre otro e Dutch Caribbean Biodiversity Database, DCNA su plataforma di notisia BioNews i prensa. E kontenido akí ta kontené e resultadonan di diferente estudio sientífiko pero e estudionan mes no ta di DCNA. No por saka ningun derecho for di e kontenido. DCNA ku e publikashon no ta legalmente responsabel pa e kontenido i e impaktonan direkto/indirekto di e artíkulo akí. 

Gutu ta mas cu djis un cara bunita. E gutu promedio ta pasa te 90% di su dia limpiando e rifnan di coral. Su piknan afila ta permitie raspa kita e alganan  facilmente di e coralnan y e barancanan, loke ta esencial pa mantene e rifnan saludabel y prospero. Specialmente awor cu e principal factornan di stress, manera e eventonan di blankia coral y malesa di perdida di tehido di piedra di coral  SCTLD (Stony coral tissue loss disease), ta importante pa yuda e rifnan di coral recupera y bolbe crece. Lo considera un mayor proteccion den e region di Caribe durante e proximo Conferencia di e partinan pa e reunion di e Convencion di Cartagena (COPS) mas despues durante e aña aki na Aruba. 

(Foto: Marion Haarsma)

E rifnan di coral ta proporciona un habitat valioso pa pisca y otro bestia. Hende tambe ta beneficia di e hopi servicionan ecosistemico cu e rifnan di coral ta brinda, incluyendo proteccion di costa, alimento y e ingresonan di turismo y pesca. De facto, e rifnan di coral ta un di e fuentenan di ingreso mas importante pa e islanan di Caribe Hulandes. 

Comedo di yerba important 

(Foto: Marion Haarsma)

Herbivoro manera gutu ta hunga un papel fundamental den mantencion saludabel di e rifnan di coral. Nan ta yuda mantene e ekilibrio delicado dentro di e rifnan door di come alga (macro), cu ta e principal competido di e coralnan pa espacio y luz. E gutu promedio ta pasa hasta 90% di su dia limpiando rif. No solamente e especienan di pisca ta mantene e alganan bou di control, sino cu tambe e herbivoronan aki ta crea espacio nobo pa e coralnan baby pega y crece. 

Ademas di elimina e macroalganan y promove asentamento y crecemento di e coralnan, e gutunan tambe ta bioerosionado natural cu ta produci sedimento door di come yerba riba e barancanan, alga calcarea y coral (menos di 10 % di su alimento). Di e manera aki nan ta yuda recicla e nutrientenan y nan ta produci “santo” pa e zonanan di costa (erosiona). 

Global Coral Reef Monitoring Network (GCRMN) nan raport titula “Status and Trends of Caribbean Coral Reefs: 1970-2012″ pa Jackson et al. (2014) a documenta tendencia cuantitativa tocante salud di e rifnan di coral durante 43 aña den Caribe Mayor. E informe ta identifica cu un di e principal impulsornan di rechaso di e rifnan di coral den Caribe ta pesca excesivo di herbivoro, particularmente di gutu. 

Menasa 

(Foto: Steph Wear)

Gutu ta prospera miho den ecosistema di rif di coral saludabel. Por lo tanto, e piscanan ey ta suheto na e mesun menasanan cu e coralnan. Esaki ta inclui e efectonan negativo di cambio climatico, e acidificacion di ocean, e contaminacion y malesa manera e malesa di perdida di tehido di coral duro. Ademas, sobrepesca por caba hopi lihe cu poblacionnan local di gutu. Estudionan ta mustra cu e rifnan ta mas saludabel y tin un mayor capacidad di resiliencia di recuperacion na luganan unda e gutunan ta proteha. Esaki ta e importancia di gutu pa cu e rifnan por recupera y bolbe crece di e menasanan aki. 

Proteccion di gutu 

Den Caribe Hulandes -na Aruba y Boneiro- ta existi norma y reglamento local pa proteha tur gutu. Na e islanan aki ta prohibi pa gara, mata, herida of molestia e gutunan. Afortunadamente pa e demas islanan di Caribe (Hulandes), Reino Hulandes, hunto cu Republica di Francia a presenta formalmente un proposicion pa inclui tur e gutunan den Anexo III di Specially Protected Areas and Wildlife (SPAW) Protocol, (Protocol di Area y Bida Silvestre specialmente Proteha), un acuerdo regional acuerdo pa proteccion y uzo sostenibel di e biodiversidad costera y marino den e Region di Gran Caribe. Si  aproba esaki durante e proximo Conferencia di e Partinan pa e Convencion di Cartagena (COPS) IGM20/COP17 mas despues durante e aña aki  na Aruba, e medida aki ta proporciona un marco legal pa conservacion di gutu pa sigura y mantene e poblacion den un nivel optimo den Caribe Mayor. 

Bo kier siña mas tocante e poblacionnan local di gutu? Consulta e siguiente articulonan relaciona cu esaki: 

Fish poop: an underappreciated food source for coral reef fishes?, 

Recovery of Orbicella annularis corals from parrotfish predation, 

Parrotfish key to reef survival,

https://www.gefcrew.org/carrcu/SPAWSTAC10/SPAW_STAC10_WG.43-INF.17_EN_Parrotfish_Inclusion.pdf\  

 DCNA

Dutch Caribbean Nature Alliance (DCNA) (Aliansa pa Naturalesa di Caribe Hulandes) ta sostene comunicacion cientifico y divulgacion den region di Caribe Hulandes door di haci cu e informacion cientifico relaciona cu naturalesa ta mas disponibel a traves di, entre otro, Dutch Caribbean Biodiversity Database, (Base di Dato di Biodiversidad di Caribe Hulandes), plataforma di noticia BioNews di DCNA y prensa. E articulo aki ta contene resultado di varios estudio cientifico, pero e estudionan riba nan mes no ta estudionan di DCNA. Ningun derecho no por wordo deriva di e contenido. DCNA no ta responsabel pa e contenido y e impacto indirecto cu resulta di publicacion di e articulo aki. 

Published in BioNews 63

Summary
The health of coral reefs is threatened by anthropogenic land-based input, which is a global problem. High nutrient conditions make corals less resilient to environmental stresses like climate change and intense weather. Poor water quality is likely for the island of St. Eustatius due to the lack of sewage treatment and its erodible coastline. However, there are no data on this island’s long-term water quality monitoring. Chlorophyll-a concentrations, used to indicate water quality, were monitored at 13 locations around St. Eustatius twice a month from May to November 2022 (n=13). Additionally, images of the ocean floor at 10m were made using a remotely operated vehicle (ROV) to monitor benthic species communities and their habitat. The main conclusion of this research shows that the reefs are primarily in an algal-dominant state. This may be explained by the frequent, chronic exceedances of the 0.2 g/l chlorophyll-a threshold. Chlorophyll -a thresholds were surpassed more frequently and with higher amounts on the sites with a larger anthropogenic influence. The lower threshold for chlorophyll-a was surpassed at 5 out of the 11 sites by more than 30% of the measurements. This would point to a more pervasive low-level eutrophic condition at all sites. On many of the sand-based substrate areas, seagrass has covered it.

For full report or more information,  please contact erik.meesters@wur.nl or gulsah.dogruer@wur.nl

Abstract

This project uses geospatial data to generate custom polygons in an interactive setting to represent the size and location of coral reefs to extract insights from coral reef-centered data sets. Historically, the data used by the Reef Restoration Group Bonaire exists in disparate sources, making it difficult to track and analyze the outcomes of their restoration work. Additionally, this information is not available in a digestible format for other audiences who would be interested in this data, such as citizen scientists seeking coral reef health statistics, the general public wanting to better understand the coral reefs surrounding Bonaire or recreational scuba divers interested in learning more about potential dive sites. Numerous data points were extracted for each reef in scope, largely from two data sources to highlight the efforts of the Reef Restoration Group Bonaire and biodiversity of each reef. These data elements were visualized using Tableau, an interactive data visualization software, which provided the vehicle for the exploration and interaction with the data. The development of the custom Tableau interface and geospatial polygons representing the coral reefs, allowed for an interactive user experience for exploration and analysis of the health and biodiversity of each reef by plotting these polygons on a world map. The outcome gave the precise location and size for each reef allowing for the identification of reef boundaries using latitude and longitude coordinates as the polygon vertices. These outcomes indicate there is a tangible benefit possible by representing geospatial data in an interactive environment for data analysis and extraction of insights.

Abstract
The concurrent rise in the prevalence of conspicuous benthic cyanobacterial mats and the incidence of coral diseases independently markmajor axes of degradation of coral reefs globally. Recent advances have uncovered the potential for the existence of interactions between the expanding cover of cyanobacterial mats and coral disease, especially black band disease (BBD), and this intersection represents both an urgent conservation concern and a critical challenge for future research. Here, we propose links between the transmission of BBD and benthic cyanobacterial mats. We provide molecular and ecophysiological evidence suggesting that cyanobacterial mats may create and maintain physically favorable benthic refugia for BBD pathogens while directly harboring BBD precursor assemblages, and discuss how mats may serve as direct (mediated via contact) and indirect (mediated via predator–prey–pathogen relationships) vectors for BBD pathogens. Finally, we identify and outline future priority research directions that are aligned with actionable management practices and priorities to support evidence-based coral conservation practices.

MSc internship report

The project Restoration of resilience of nature and society in the Caribbean Netherlands aims to improve the resilience of the coral reefs in the BES (Bonaire, Sint Eustatius, Saba) islands, by mitigating the local stressors. One of the methodologies used is water quality monitoring. For this research, the focus was on chlorophyll a and turbidity temporal and spatial variability in Saba, and on how this could be related to anthropogenic and natural land-based local stressors. Chlorophyll a is a key water quality parameter which can give an insight on the eutrophic state of an area, while turbidity can be used as an indicator for coastal erosion and run-offs. These parameters were measured in 13 sampling sites, bi-weekly from May to August 2022, using two CTDs, a sensitive sensor technology. The land-based stressors were mapped as a result of qualitative analysis. Chlorophyll a values were highly variable, and often exceeded the safety threshold (0.2 μg/L) previously chosen, suggesting that the area was in a chronic state of eutrophication. Turbidity instead remained more stable and nearly always below the 3 NTU threshold. On one hand, spatial variability was not always directly linked to land-based stressors, and might be better interpreted including the action of sea currents. Temporal fluctuations, on the other hand, can be only partly explained by the amount of rainfall increasing run-offs from land to sea. Moreover, further research is needed to quantify local stressors, and long-term monitoring is necessary to fully understand the amplitude and nature of their influence on water quality.

For full report or more information,  please contact erik.meesters@wur.nl or gulsah.dogruer@wur.nl

MSc internship report

The health of coral reefs is threatened by anthropogenic land-based input, which is a global problem. High nutrient conditions make corals less resilient to environmental stresses like climate change and intense weather. Poor water quality is likely for the island of St. Eustatius due to the lack of sewage treatment and its erodible coastline. However, there are no data on this island’s long-term water quality monitoring. Chlorophyll-a concentrations, used to indicate water quality, were monitored at 13 locations around St. Eustatius twice a month from May to November 2022 (n=13). Additionally, images of the ocean floor at 10m were made using a remotely operated vehicle (ROV) to monitor benthic species communities and their habitat. The main conclusion of this research shows that the reefs are primarily in an algal-dominant state. This may be explained by the frequent, chronic exceedances of the 0.2 g/l chlorophyll-a threshold. Chlorophyll -a thresholds were surpassed more frequently and with higher amounts on the sites with a larger anthropogenic influence. The lower threshold for chlorophyll-a was surpassed at 5 out of the 11 sites by more than 30% of the measurements. This would point to a more pervasive low-level eutrophic condition at all sites. On many of the sand-based substrate areas, seagrass has covered it.

For full report or more information,  please contact erik.meesters@wur.nl or gulsah.dogruer@wur.nl