Marine

Although coral reefs are well developed in the Leeward islands of the Netherlands Antilles, they are poorly developed in the Windward group. Coral communities are common in the Dutch Windward islands, but no structural reefs have been observed. Flat, sandy bottoms there seem to prevent reef development, as is also the case on large parts of the southwest coast of Aruba.

The zonation of corals on the reefs, with respect to depth, distance from shore, and conformation to the bottom, resembles that of other Caribbean reefs. Density of living-coral cover ranges in the several zones from nearly zero to almost 100%. Below 20 to 25 m on the forereef slope the corals are areally less abundant than crustose coralline algae. Generic diversity of hermatypic corals is comparable in the Leeward and Windward groups of the Dutch islands, with 24 and 23 genera present, respectively. These numbers are comparable to those of other highly diverse reefs in the Caribbean. The number of species in the Windward group, however, is relatively low. The differences in abundance of coral genera (and species) throughout the Caribbean needs more thorough investigation.

Linear extension of branches in the same Acropora palmata (Lamarck, 1816) population in Curaçao was measured, employing exactly the same methods, in 1971–1973 and in 2002–2004, and the resulting coral growth rates are compared. Linear growth shows the same pattern over seasons in both periods with growth being significantly higher in summer than in winter. Growth in the 2002–2004 time interval was significantly slower than in 1971–1973. Mean monthly growth ranged from 0.69 cm (winter) to 0.81 cm (summer) in 1971–1973 and from 0.62 cm (winter) to 0.75 cm (summer) in 2002–2004. This means that linear growth rates in 2002–2004 were 7.2% lower in summer and 10.7% lower in winter compared with 1971–1973. Considering possible causative environmental factors relating to these decreases in growth rate, we cannot preclude the possibility that a change in ocean pH could be responsible for the drop in extension rate.

Abstract:

Lionfish are venomous, predatory reef fish native to the Indo-Pacific region, but have become widely distributed due to its popularity as an aquarium fish. Due to high fecundity, adaptability to non-native habitats and tolerance to large temperature and depth ranges, the lionfish invasion has the potential to become the most detrimental in history. Lionfish were first confirmed in Bonaire on 26th October, 2009. Since then, despite active eradication attempts, they have increased in abundance, occupying habitats at a range of depths. Trinidad and Tobago however have yet to be invaded by lionfish, but the presence of lionfish in aquariums in Trinidad and the availability of suitable prey and habitat, together with confirmed lionfish sightings in neighbouring territories make the lionfish invasion imminent. Questionnaires were conducted with target groups (lionfish-hunters, divers, dive- shops, fishermen and pet-shop owners) in Bonaire and Trinidad and Tobago. These revealed that there was a significant difference in the level of opinions and awareness between the invaded territory (Bonaire) and the un-invaded territory (Trinidad and Tobago). The current lionfish management strategies in Bonaire and the Caribbean were also appraised to suggest the best approach for Trinidad and Tobago in dealing with the future threat of lionfish. 

Findings

The main conclusion from this study is that the Saba Bank has little modern material/ sediment deposited in relation to present sea level. This contradicts with previous beliefs such as Spencer’s claim that the bank surface “has been leveled by coral growth and sands derived from them”.

The study found the following:

• Minimal reef development.
  • Limited data from the survey revealed a sparse coral cover but   abundant crustose coralline algae and sponges.
  • The Saba community showed no sign of forming an interlocking reef framework.
• Sediments rich in residual material derived from late Cenozoic limestone bedrock.
• Most samples from this area had relatively large quantities of calcite, which suggests erosion of bedrock on Saba Bank.
• The internal structure of Saba Bank remains unknown; the surveys lacked sufficient sub-bottom penetration to disclose information about internal structure.

The St. Maarten Nature Foundation conducted an Economic Valuation of St. Maarten’s coral reef ecosystems in the fall of 2010. This attempted to put a monetary estimate on the coral reefs surrounding the island. Coral Reefs are one of the island’s most valuable resources; they provide a livelihood through dive tourism and fishery and provide protection from large, damaging waves caused by hurricanes. In order to properly manage the coral reef ecosystem, an economic valuation is a useful tool to determine what exactly the monetary value of a coral reef is. With an attached value, better management decisions can be made to adequately protect this most precious of resources.

In order to complete the study four questionnaires were distributed. Two dealt specifically with fisheries, one with hotel accommodations, and one with dive tourism. Data was also provided through independent research and stakeholder analysis. Coral reefs have direct and indirect influences on a wide range of economic factors, and the generation of data was crucial to the successful completion of this study. Data was inputted into a computer program created by the United Nations Environment Program and the World Resource Institute (WRI) and which was adjusted by the St. Maarten Nature Foundation to reflect St. Maarten’s unique ecological and economic situation.

The findings of this study have outlined that St. Maarten’s coral reef resources provide important goods and services to the economy of the island. The revenue that the resource is able to generate through coral reef associated tourism and fishery is approximately USD $57,586,976. Although this number is high, and highlights the importance of coral reefs to the island, it also suggests that there is an increased need for conservation in order for this value not to diminish. It is therefore in the best interest of St. Maarten to incorporate environmental economic data to: (1) Establish Marine Protected Area, (2) Incorporate economic valuation into EIAs, (3) Include economic impacts in assessing fines for damages to coral reefs from activities such as anchoring in the reserves, oil spills etc, (4) Weigh revenues from a growing tourism industry against long-term economic losses from environmental impacts, (5) Evaluate distributional effects (“winners” and “losers”) of proposed coastal development projects, (6) Invest in Scientific Research, (7) Increase support from the private and public sector in the proposed Marine Park Management Authority, St. Maarten Nature Foundation. 

In this report we review and assess possible consequences of climate change for the biodiversity of the Dutch BES islands (Bonaire, Saba and St. Eustatius), and present various options for adaptation. From our review it is quite clear that climate change not only poses a severe threat to the ecosystems of the BES islands, but also to the totality of benefits and services the inhabitants of these islands derive from those ecosystems. Key changes in climate expected this century include increases in air and sea surface temperature, an increase in sea level and ocean acidity, an increase in the frequency and intensity of storms and hurricanes, general aridification and greater overall unpredictability in weather. The consequences for both terrestrial and marine biodiversity are predicted to be far-reaching. The principal effects will likely include further losses to the coral reef systems, erosion of coasts and beaches, salinification of ground water sources, losses in hilltop vegetation and flora, soil humus losses and erosion, increases in various disease vectors, changes in ocean currents, fish recruitment and migration, and a stronger foothold for invasive species.

The main areas of environmental policy involving the management of biodiversity are those of land-use planning and zoning, forestry and terrestrial conservation, and marine conservation. As for land-use planning and zoning, main issues of concern will be the introduction of the 'set back' policy for coastal development, the preservation of the full range of key habitats, and sufficient habitat surface area to sustain minimum viable populations for native species. In addition these habitats must be ecologically connected to allow free movement of animals across the habitats they need throughout the different seasons of the year and phases of their life cycle. In terms of forestry and terrestrial conservation policy, the focus will especially need to be on solving the problem of uncontrolled grazing of livestock, and the implementation of reforestation and groundwater conservation. Key issues in marine conservation policy will be to tackle the technically and financially challenging problem of eutrophication and the socially controversial limits to the harvest of reef organisms.

While it is the large industrialized countries that drive man-induced climate change, it is the small island developing states (SIDS) and small coastal states that will suffer the most from climate change. In this respect it may be especially valuable for the BES islands to develop and participate in larger efforts to convince (pressure, lobby) the large industrialized nations to adopt those changes needed in their industrial and energy policies by which to avert the most disastrous scales of global climate change. As the stakes are obviously very high, the BES islands should seek to actively develop and/or participate in such efforts. However, to do this credibly and convincingly will require the islands to develop their own vision and policy and to implement important measures of their own. While the topic of climate change has recently come to the attention of government, preparation and readiness for climate change lags behind.

The main options for local adaptation measures as outlined all come down to just one principle: to 'manage for resilience' of the ecosystems as much as possible by reducing the stress induced by local anthropogenic pressures. This will require proper data and knowledge as well as a proper monitoring of impacts and results. In this, investment in baseline inventories, dedicated research and a monitoring system is essential.

If international resolve falters and precipitous global climatic change cannot ultimately be avoided, large ecological regime shifts may cause ecosystems and species in any given area to become ecologically untenable, and introduced species to become firmly established and impossible to eradicate. If so, it will be important to make hard choices and not waste valuable time and resources fighting lost causes. Therefore, in the future successful management of natural resources will often require managers and decisions makers to think differently than in the past, to abandon old paradigms and objectives, and to focus more on general ecosystem services than on specific details. Hence our ability and willingness to adaptively 'manage for change' will be critical, as will be the need for effective decision making under conditions of complexity, uncertainty and imperfect knowledge.

Doel en achtergrond werkbezoek

Sinds 10 oktober 2010 maken Bonaire, Sint Eustatius en Saba deel uit van Nederland. Rijkswaterstaat heeft wettelijke verantwoordelijkheden voor deze eilanden. Hieronder valt het opzetten van een operationele maritieme incidentenorganisatie. Gezien de enorme olie-overlagbedrijven op Sint Eustatius en Bonaire, de economische afhankelijkheid van de eilanden van duik toerisme en gezien de biodiversiteit in (de zeeën rond) Caribisch Nederland is dit geen overbodige luxe. RWS Noordzee zet de incidentenorganisatie op. De landelijke coördinatiecommissie milieuincidenten (LCM) ondersteunt hierbij. Doel van de reis naar Caraïbisch Nederland (CN) was om te komen tot een advies over de olie-bestrijdingsmogelijkheden, waaronder mechanisch opruimen en het gebruik van detergenten.

Mechanisch opruimen

Bij oliebestrijding is de keuze voor de wijze van bestrijding belangrijk. Het standaard uitgangspunt van de oliebestrijding is het verwijderen van de gemorste olie uit het milieu (mechanisch opruimen). Gedurende de reis is geïnventariseerd welke middelen beschikbaar zijn en wat noodzakelijk is om de opruimcapaciteit op het afgesproken niveau te brengen (tier 1, 16 m3).

Gebruik detergenten

Er zijn situaties waarbij de inzet van detergenten kwetsbare kustzones kan beschermen. Om het gebruik van detergenten te ondersteunen is een beslisboom detergenten beschikbaar. Voor het Caraïbisch beheergebied moet deze beslisboom worden aangepast. Voor het toepassen van detergenten is het van belang inzicht te hebben in de verspreiding van olie op zee. In Europees Nederland wordt gebruik gemaakt van het operationele model oilmap. Voor CN is het van belang dat dit model ook ingezet kan worden.

Adviezen

Het advies is gericht op het beperken van de belangrijkste risico’s en op maatregelen die op korte termijn gerealiseerd kunnen worden.

Reefs of the windward Netherlands Antilles (Saba, Saba Bank, St. Eustatius, St. Maarten) were assessed at 24 sites in the late 1999. The Atlantic and Gulf Rapid Reef Assessment (AGGRA) protocol was used with modifications to detect recent hurricane impacts. Live coral cover averaged 18%. The assemblage of >10 cm stony corals was primarily composed of small-sized colonies (mean diameter = 37 cm) of which the Montastraea annularis complex was the most abundant (30% of colonies). Overall, =1% of the individually surveyed colonies had been physically damaged by Hurricane Lenny but injury levels were higher in Saba (2.6%). Bleaching was noted in 23% of colonies at the time of the assessment with the greatest percentage occurring on St. Maarten (44%) and the lowest on Saba Bank (9%). Total (recent + old) partial mortality of reef-building corals averaged less than 18% although levels were higher (26%) in Colpophyllia natans. Coral recruitment densities were relatively consistent (mean = 5 recruits/m2) across sites. Commercially significant fish species (i.e. serranids, lutjanids, haemulids >5 cm) were present with mean densities of 4.5 individuals/100 m2. High biomass (mean = 5.8 kg/100 m2) of grazing, herbivorous fishes (acanthurids, scarids >5 cm, Microspathodon chrysurus) partially explains the relatively low macroalgal cover (mean = 7%) throughout this area. Saba’s fish community had a greater total biomass than those in the other three geographic areas (mean = 11 kg/100 m2 versus 7 kg/100 m2). While the coral reefs of St. Maarten show signs of disturbance (i.e., increased bleaching and sedimentation), those of Saba, Saba Bank, and southern St. Eustatius have been relatively little disturbed by coastal development and remain potential sources of marine life. Nevertheless, reef development in the windward Netherlands Antilles is limited by frequent hurricanes.

Abstract:

Although Bonaire’s coral reefs remain among the healthiest and most resilient in the Caribbean, this IUCN report based on the IUCN Resilience Assessment of Coral Reefs highlights some of the threats that exist to Bonaire’s coral reefs, and which could have serious implications for resilience to future climate change and other threats. The report identified recommendations for addressing the current threats, as well as high and low resilience sites.

The threats and recommendations identified include:

Coastal development and artificial beaches.
Recommendation: All coastal construction on Bonaire should be strictly regulated and follow the construction guidelines. The guidelines should become law in order to be enforced appropriately.

Leaching from septic tanks.
Recommendation: It is strongly recommended that Bonaire invest in appropriate sewage treatment facilities to improve water quality and increase the resilience of its valuable coral reefs. It is also recommended that a water quality monitoring program be set up and sustained.

Increasing damselfish populations.
Recommendation: It is recommended that the fishing of predatory fish species on Bonaire’s coral reefs be controlled and managed to a sustainable level to prevent population explosions of prey fish capable of modifying the reef habitat.

Trididemnum and Lobophora.
Recommendation: It is recommended that the populations of Trididemnum and Lobophora are closely monitored and the factors contributing to the unnatural abun- dance of these coral-overgrowing organisms should be studied and then eliminated.

Due to a variety of factors affecting resilience which were assessed using the IUCN methodology, sites were also ranked according to their overall resilience: 

It is noteworthy that sites with lowest resilience ratings (e.g. Chachácha) are those most impacted by coastal development, while sites with highest resilience ratings (e.g. Marine Reserve North, Playa Frans, Karpata, Margate Bay, Vista Blue and South Bay) are those furthest away and least impacted by coastal development.