Coral reefs

Assessment of Ramsar site Lac Bonaire – June 2010

Findings

The main issues that Lac Bay faces were identified as follows:

  1. Filling-in of Lac and reduced water circulation. Over-grazing by extensive livestock husbandry as well as non-sustainable land-use practices (e.g. barren fields) has resulted in an accelerated infilling of the bay with sediment, which hampers water circulation and causes mangrove die-off. This has lead to a gradual reduction of the effective nursery and habitat surface of the bay over the last decades.
  2. Increase in uncontrolled recreational pressure. The Lac ecosystem has been modified or altered by construction of roads, the building of hotels, subterraneous nutrient enrichment by untreated sewage and more. Trampling is causing an important decrease in sea grass bed coverage in the bay. Endangered species such as turtles and nesting birds are vulnerable to human disturbance (Lac is intensively used for various kinds of recreation).
  3. Litter contamination. Marine litter washed in from the open ocean and abandoned fishing lines in the deeper parts of Lac are big issues.
  4. Algal blooms. While the outer reef is in very good health, many of the inner reef’s corals, gorgonians and sponges are being overgrown by the crustose calcareous alga Ramicrusta sp. This may cause a serious decline in living corals inside the bay.

Management Recommendations:

The highest priority is to start habitat restoration.

Direct enforcement of existing and new legislation is crucial as well as a permanent presence of one or more officials.

Filling-in of Lac and reduced water circulation

  • Tackle the livestock overgrazing problem in the whole watershed.
  • Regularly open up the former channels to the rear areas of the mangroves and re-establish circulation and water quality.
  • Remove filled-in sediments and reforest with red mangroves in the rear stagnant areas of Lac so as to re-establish mangrove and fish nursery habitat.

Address increase in uncontrolled recreational pressure

  • Set upper limits for the various users.
  • Strictly limit public access to seagrass areas using a combination of zoning, demarcation and enforcement.
  • Upgrade the visitor facilities designed to limit or steer user impact towards low sensitivity areas.
  • Monitor the human use of the bay.
  • Assess Lac’s current bird use and their vulnerability to disturbance.

Litter contamination

  • Conduct regular cleanups with volunteers and monitor litter densities.
  • Limit and regulate fishing inside of Lac.
  • Conduct PAH  (polyaromatic hydrocarbon) studies of the water in Lac.

Algal blooms

  • Periodic annual monitoring of enteric bacterial presence at high risk locations.
  • Install a monitoring program to assess the nutrient situation in Lac at several locations.
  • Continue monitoring of coral overgrowth by Ramicrusta sp. 
Date
2010
Data type
Research report
Theme
Research and monitoring
Report number
C066/10
Geographic location
Bonaire

Community Change within a Caribbean Coral Reef Marine Protected Area following Two Decades of Local Management

Structural change in both the habitat and reef-associated fish assemblages within spatially managed coral reefs can provide key insights into the benefits and limitations of Marine Protected Areas (MPAs). While MPA zoning effects on particular target species are well reported, we are yet to fully resolve the various affects of spatial management on the structure of coral reef communities over decadal time scales. Here, we document mixed affects of MPA zoning on fish density, biomass and species richness over the 21 years since establishment of the Saba Marine Park (SMP). Although we found significantly greater biomass and species richness of reef-associated fishes within shallow habitats (5 meters depth) closed to fishing, this did not hold for deeper (15 m) habitats, and there was a widespread decline (38% decrease) in live hard coral cover and a 68% loss of carnivorous reef fishes across all zones of the SMP from the 1990s to 2008. Given the importance of live coral for the maintenance and replenishment of reef fishes, and the likely role of chronic disturbance in driving coral decline across the region, we explore how local spatial management can help protect coral reef ecosystems within the context of large- scale environmental pressures and disturbances outside the purview of local MPA management. 

Date
2012
Data type
Scientific article
Theme
Governance
Research and monitoring
Journal

Attraction of settlement-stage coral reef fishes to reef noise

We compared catches of settlement-stage reef fishes in light traps attached to underwater speakers playing reef sounds with those of silent traps during a summer recruitment season at Lizard Island, Great Barrier Reef, Australia. Of the total 40191 reef fishes we collected, significantly more (67%; Wilcoxon and Binomial tests: p< 0.001) appeared in the traps with broadcast reef noise. Traps deployed with speakers consistently caught a greater diversity of species (Wilcoxon test: p< 0.001, total 81 vs 68) than did silent traps. This study provides a clear demonstration that the settlement-stages of a broad range of families of coral reef fishes are attracted to reef sounds

Date
2004
Data type
Scientific article
Theme
Research and monitoring

Rapid Assessment of Stony Coral Richness and Condition on Saba Bank, Netherlands Antilles

Findings:

Combining the findings of this study with that of other studies, the authors conclude that the coral assemblage on the Saba Bank is diverse and healthy; it is representative and typical of those found elsewhere in the Caribbean.

Coral Richness

  • A total of 43 species were documented.
  • There were no significant differences in coral composition amongst bottom types or depth classes.
  • There was a significant difference between sites near and far from the platform edge. The number of coral species observed ranged from 0 and 1 in algal dominated habitats to 23 at a reef habitat on the Bank’s southern edge.
  • Coral species richness was higher on reef dominated areas as opposed to algal dominated ones.

Coral Condition

  • Bleaching was evident at 82% of the sites assessed with 43 colonies bleached.
  • Only three coral colonies were observed to have disease.
  • Five reef sites had stands of Staghorn Coral (Acropora cervicornis), a critically endangered species on the IUCN Red List.
  • No physical damage consistent with anchor usage or sand scour from shipping activity was noted at any of the sites assessed.

Management Recommendations

  1. Immediate action is necessary to protect the diverse coral reef habitats documented.
  2. The five healthy stands of staghorn coral (A. cervicornis) and their surrounding should be given highest priority for full protection in the zoning use plan under development (in consultation with all stakeholders).
  3. More information is needed on the Saba Bank to create a comprehensive zone use plan. For example, more sites need to be studied so as to get a more comprehensive coverage of the bank’s coral composition.
Date
2010
Data type
Scientific article
Journal
Geographic location
Saba bank

Bonaire National Marine Park (BNMP) op weg naar werelderfgoed

Het Bonaire National Marine Park (BNMP) staat sinds 2011 op de Nederlandse Voorlopige lijst van het Werelderfgoed. Dit betekent dat een nominatie kan worden ingediend om als natuurlijk werelderfgoed erkend te worden. In dit rapport wordt beschreven welke stappen nodig zijn om tot een nominatie voor de status van werelderfgoed te komen.

De ‘Outstanding Universal Value’ (datgene wat het gebied wereldwijd uniek maakt) moet worden aangetoond. Hierbij zijn drie aspecten van belang:

  1. Het gebied moet voldoen aan minimaal één van de vier door UNESCO gestelde criteria voor natuurlijke werelderfgoederen;
  2. Het gebied moet voldoen aan condities voor integriteit;
  3. Het beheer van het gebied moet voldoende zijn om de kwaliteit van het ecosysteem van het BNMP veilig te stellen voor de komende generaties.

Verder moet het gebied en haar OUV worden vergeleken met vergelijkbare werelderfgoed gebieden en met vergelijkbare gebieden elders in de wereld door middel van een Comparative Analysis.

De hele procedure is in dit rapport samengevat in een schematisch stappenplan. Omdat er zware eisen gesteld worden aan de nominatie zijn in dit stappenplan ook beslismomenten aangegeven waarop aan bepaalde voorwaarden voldaan moet zijn om verder te gaan met de aanvraag (zogenaamde ‘go/no-go’ momenten).

Aangezien de hele procedure de nodige financiële middelen vraagt, moet min of meer zeker zijn dat de nominatie haalbaar lijkt voordat aan de verschillende onderdelen van de nominatie begonnen wordt. 

Date
2012
Data type
Research report
Theme
Research and monitoring
Report number
C140/12
Geographic location
Bonaire

Biodiversity Assessment of the Fishes of Saba Bank Atoll, Netherlands Antilles

Abstract:

Biodiversity surveys were conducted on Saba Bank, Netherlands Antilles, to assess ichthyofaunal richness and to compare with published surveys of other Caribbean localities. The primary objective was to estimate the total species richness of the Saba Bank ichthyofauna. A variety of sampling techniques was utilized to survey the fish species of both the visually accessible megafauna and the camouflaged and small-sized species comprising the cryptic ichthyofauna. Based on results presented herein, the number of species known on Saba Bank is increased from 42 previously known species to 270 species. Expected species-accumulation curves demonstrate that the current estimate of species richness of fishes for Saba Bank under represents the actual richness, and our knowledge of the ichthyofauna has not plateaued. The total expected fish species richness may be somewhere between 320 and 411 species. The Saba Bank ichthyofaunal assemblage is compared to fish assemblages found elsewhere in the Caribbean. Despite the absence of shallow or emergent shore habitats like mangroves, Saba Bank ranks as having the eighth highest ichthyofaunal richness of surveyed localities in the Greater Caribbean. Some degree of habitat heterogeneity was evident. Fore-reef, patch-reef, and lagoonal habitats were sampled. Fish assemblages were significantly different between habitats. Species richness was highest on the fore reef, but 11 species were found only at lagoonal sites. A comprehensive, annotated list of the fishes currently known to occur on Saba Bank, Netherland Antilles, is provided and color photographs of freshly collected specimens are presented for 165 of the listed species of Saba Bank fishes to facilitate identification and taxonomic comparison with similar taxa at other localities. Coloration of some species is shown for the first time. Preliminary analysis indicates that at least six undescribed new species were collected during the survey and these are indicated in the annotated list. 

Date
2010
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Saba bank

Unforeseen importance of historical collections as baselines to determine biotic change of coral reefs: the Saba Bank case

Botanical and zoological collections may serve as archives for historical ecologi- cal research on the effects of global change and human impact on coral reef biota. Museum collections may harbour old specimens of reef-dwelling species that have become locally extinct. Such collections also help to determine whether early records of invasive species can be obtained from times when they were not yet recognized as such. A case study (2006) involving Saba Bank, Caribbean Netherlands (former Netherlands Antilles), suggests that the coral reef fauna here may have become impoverished when compared with data obtained during an earlier expedition in 1972. However, the 1972 sampling may have been incomplete, as it was performed by professional divers who were not trained taxonomists, whereas the collecting in 2006 was done by expe- rienced marine biologists who knew the taxa they were sampling. As Saba Bank has been under stress due to the anchoring of large vessels, and invasive species have been a potential threat as well, future studies are needed to obtain more insights into the changing reef biota of Saba Bank. Using this Saba Bank exam- ple, we want to address the importance of natural history collections as reser- voirs of valuable data relevant to coral reef biodiversity studies in a time of global change. As such, these collections are still underexplored and underexploited. 

Date
2011
Data type
Scientific article
Theme
Research and monitoring
Journal
Geographic location
Saba bank

Multi-scale habitat occupancy of invasive lionfish (Pterois volitans) in coral reef environments of Roatan, Honduras

The Indo-Pacific lionfish species [Pterois volitans (Linnaeus, 1758) and P. miles (Bennett, 1828): Family Scorpaenidae] are the first nonnative marine fishes to establish in the Western North Atlantic and Caribbean Sea. Despite the continued documentation of its range expansion and highly publicized invasion (including public-driven removal efforts) there remains a paucity of basic information on lionfish ecology. This knowledge gap limits effective long-term management. In this study we conducted a multi-scale investigation of habitat occupancy of a newly established population of lionfish in Roatan, Honduras. Based on field surveys and citizen sightings in Roatan Marine Park we found that lionfish occurred more frequently on aggregate coral reef habitats (54% of sightings) compared to patch reef habitats (30%) and sea grass lagoons (16%). In general, these aggregate and patch reef habitats contained adults (mean total length =118.9 mm and 114.7mm, respectively) whereas sea grass habitats contained juveniles (mean total length=89.5 mm). At the micro-habitat scale lionfish occupied areas dominated by hard coral and overhanging structure; the same microhabitats containing native fishes of concern – grouper (Nassau grouper, Epinephelus striatus; yellow fin grouper, Mycteroperca venenosa) and snapper (dog snapper, Lutjanus jocu; mutton snapper, Lutjanus analis). Results from this study contribute information on basic habitat requirements of lionfish and inform current management removal efforts focused on containing spread and mitigating their impacts on native species

Date
2011
Data type
Scientific article
Theme
Research and monitoring