Caribbean coral reefs are in decline and the deployment of artificial reefs, structures on the sea bottom that mimic one or more characteristics of a natural reef, is increasingly often considered to sustain ecosystem services. Independent of their specific purposes, it is essential that artificial reefs do not negatively affect the already stressed surrounding habitat. To evaluate the ecological effects of artificial reefs in the Caribbean, an analysis was performed on 212 artificial reefs that were deployed in the Greater Caribbean between 1960 and 2018, based on cases documented in grey (n = 158) and scientific (n = 54) literature. Depending on the availability of data, reef type and purpose were linked to ecological effects and fisheries management practices around the artificial reefs. The three most common purposes to deploy artificial reefs were to create new dive sites (41%), toperform research (22%) and to support ecosystem restoration (18%), mainly by stimulating diversity. Ship wrecks (44%), reef balls© (13%) and piles of concrete construction blocks (11%) were the most-often deployed artificial reef structures and metal and concrete were the most-used materials. The ecological development onartificial reefs in the Caribbean appeared to be severely understudied. Research and monitoring has mostly been done on small experimental reefs that had been specifically designed for science, whereas the most commonly deployed artificial reef types have hardly been evaluated. Studies that systematically compare the ecological functioning of different artificial reef types are virtually non-existent in the Caribbean and should be a research priority, including the efficacy of new designs and materials. Comparisons with natural reef ecosystems are scarce. Artificial reefs can harbor high fish densities and species richness, but both fish and benthos assemblages often remain distinct from natural ecosystems. Studies from other parts of the world show that artificial reefs can influence the surrounding ecosystem by introducing non-indigenous species and by leaking iron. As artificial reefs attract part of their marine organisms from surrounding habitats, intensive exploitation by fishers, without clear management, can adversely affect the fish stocks in the surrounding area and thus counteract any potential ecosystem benefits. This study shows that over 80% of artificial reefs in the Caribbean remain accessible tofishers and are a risk to the surrounding habitat. To ensure artificial reefs and their fisheries do not negatively affect the surrounding ecosystem, it is imperative to include artificial reefs, their fisheries and the surrounding ecosystem in monitoring programs and management plans and to create no-take zones around artificial reefs that are not monitored.
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The purpose of this study was to identify predictors of oral hygiene behaviour (OHB) based on the Theory of Planned Behaviour (TPB) among dental care seekers in two cultural different regions: the Caribbean (Aruba/Bonaire) and Nepal. In addition, measures of oral health knowledge (OHK) and the expected social outcomes of having healthy teeth (ESO) were investigated. The main effects of the predictors as well as their interactions with region (Caribbean vs. Nepal) were examined. The interaction term contributed significantly to the amount of explained variance. In the Caribbean, OHB was determined by Attitude and Social Norms, and in Nepal by Perceived Behaviour Control and ESO. On the basis of these findings, quite different oral health care interventions are called for in developing and underdeveloped countries.
DOCUMENT
That coral reefs are in decline worldwide, particularly in the Caribbean, will come as no surprise. This decades-long decline has reached a potential tipping point as the weight of the effects of climate change have come decidedly to bear on the planet’s most diverse marine ecosystem. Whether coral reefs can persist without restorative intervention is debatable, which has prompted a surge in coral reef restoration projects focusing primarily on the cultivation and transplantation of coral fragments onto degraded reefs. But that widespread approach does little to address the underlying causes of coral loss, one of which is the proliferation of macroalgae that are deleterious to corals. An emerging solution to this problem is the enhancement of herbivory on coral reefs through improved management of herbivores, artificial enhancement of herbivore settlement, or their mariculture and subsequent stocking. This review explores the nuances of the biology of well-studied Caribbean coral reef herbivores (fishes, sea urchins, and crabs) as it relates to their mariculture and investigates the promise of herbivore stocking onto coral reefs as a restoration strategy.
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Worldwide, coral reefs are rapidly declining due to increased sea water temperatures and other environmental stresses (Figure 1). To counter the extinction of major coral reef building species on the island of Bonaire, the non-profit organization Reef Renewal Foundation Bonaire is restoring degraded reef sites using corals that are grown in local nurseries. In these nurseries, corals are propagated on artificial trees using fragmentation. After 6-8 months of growth in the nursery, the corals are transplanted to degraded reef sites around the island. Over the years more than 21.000 corals have been outplanted to reef restoration sites in this way. These corals show high survivorship under natural reef conditions but remain under threat by environmental disturbances, such as increased water temperatures, diseases, and competition with macroalgae. A promising intervention to increase reef persistence and resilience is to manipulate the coral-associated microbiome. At present, the composition of the microbiome in nursery-reared and outplanted corals on Bonaire is unknown. The aim of the current project is to identify and isolate naturally occurring beneficial bacteria that may stimulate the resilience of these corals. Our key objectives are: 1) to assess the presence of functionally beneficial bacteria in corals in nursery and restoration sites on Bonaire using metagenomic screening. 2) to design culture strategies to isolate these functionally beneficial bacteria. In the future, a selection of these beneficial bacteria can be applied to the corals to increase their resilience against environmental disturbances.
De koraalriffen van de Caribisch Nederlandse eilanden St. Eustatius en Saba zijn van groot ecologisch en economisch belang. Door een opeenstapeling van bedreigingen is de hoeveelheid driedimensionale structuur op het rif afgenomen en zijn herbivore sleutelsoorten verdwenen. Het rif wordt overwoekerd met algen, die nieuwe koraalaanwas bemoeilijken. Lokale natuurbeheerorganisaties STENAPA en SCF willen artificiële riffen inzetten, om het ecosysteem door middel van “Building with Nature” te herstellen. Artificiële riffen worden wereldwijd in toenemende mate gebruikt, maar de doeltreffendheid hangt in sterke mate af van hoe er rekening is gehouden met de lokale omstandigheden en doelstellingen. Als de riffen goed functioneren kunnen sleutelsoorten herstellen en kan koraal zich weer vestigen. De natuurbeheerorganisaties willen weten hoe artificiële riffen optimaal bij kunnen dragen aan het herstel van het koraalrif ecosysteem bij St. Eustatius en op de Saba bank. Van Hall Larenstein, STENAPA, SCF, IMARES, CNSI en Golden Rock Dive Centre werken samen in het AROSSTA (Artificial Reefs on Saba and Statia) project om deze vraag te beantwoorden. Hiervoor worden verschillende soorten artificiële riffen gebouwd van lokaal natuursteen en van veelgebruikte “reef balls”. De functionaliteit van de verschillende soorten artificiële riffen wordt bepaald door gedurende 1,5 jaar de vestiging van zee-egels, vissen en koraal te onderzoeken. Na afloop van dit project zal duidelijk zijn welk type artificieel rif het meest geschikt is voor beide onderzoeklocaties. Daarnaast is bekend wat het effect is van het gebruikte materiaal en het aanbrengen van extra schuilplaatsen op de functie van artificiële riffen. Tenslotte wordt inzicht gegeven in hoeverre artificiële riffen een bijdrage leveren aan het herstel van aangrenzende gebieden. Omdat het onderzoek uitgevoerd wordt op twee locaties, met contrasterende omstandigheden, zullen de resultaten van regionaal belang zijn om bestaande en toekomstige artificiële riffen optimaal te laten functioneren.
Many Caribbean reefs have shifted from coral-dominated to algal-dominated ecosystems. The high algae cover reduces coral recruitment, making the reef unable to recover from other disturbances and resulting in flatter reefs with lower biodiversity. One of the reasons for the proliferation of algae is a mass die-off of the herbivorous sea urchin Diadema antillarum in the early 1980s. Natural recovery of Diadema populations is slow to non-existent, making active restoration of this important grazer a top priority in Caribbean coral reef management, especially since Diadema densities were reduced by another mass mortality event in 2022. The marine park organizations of Saba and St. Eustatius want to restore Diadema populations by restocking cultured individuals. However, important knowledge gaps need to be addressed before large numbers of Diadema can be restocked on the reef. Current culture methods can only produce a limited number of competent larvae. In addition, only 8% of the settlers survive and after restocking, survival on the reef is low as well. In the RAAK PRO Diadema II project, the bottlenecks in Diadema culture will be addressed by comparing larval survival across multiple culture methods and investigating the relation between larval size and post-settlement survival. Growing-out juveniles at sea is likely to help prepare them for life in the wild, while restocking at an optimal size might also increase survival. Finally, a thorough restocking site selection based on high shelter availability and settlement rates will increase the long-term Diadema densities. The acquired knowledge and developed practices will be verified in a larger scale restocking experiment involving at least 5000 Diadema urchins. By restoring Diadema populations through restocking, macroalgae will be more intensively removed and corals will have a chance to settle and to survive, increasing the ability of the reef to cope with other stressors.
