Meesters, E.H.W.G.

Observations on the whale shark (Rhincodon typus) in the Dutch Caribbean

Abstract:

Records of whale sharks in the Caribbean are relatively sparse. Here we document 24 records of whale sharks (Rhincodon typus Smith 1882) for the Dutch Caribbean, four for the windward islands of Saba, St. Eustatius and St. Maarten, and twenty for the southern Caribbean leeward islands of Aruba, Curaçao and Bonaire. The results suggest a higher abundance of whale sharks in the southern, leeward part of the Dutch Caribbean, likely associated with seasonal upwelling-driven productivity known for the southeastern Caribbean area. A bimodal seasonal pattern as documented for Venezuela was not as pronounced in our findings for the Leeward Dutch Caribbean and whale sharks were recorded in 9 months of the year. In the Windward Dutch Caribbean all (4) records so far were for the winter months of December-February. Most records involved large and solitary animals in contrast to areas elsewhere suspected of being nursery habitat. According to local sources, whale sharks were most often associated with feeding tunas and sea surface swarms of crab megalopae. 

Date
2013
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
Saba
Saba bank
St. Eustatius
St. Maarten

Use of satellite data for the monitoring of species on Saba and St. Eustatius.

Abstract:

On 10 October 2010 Bonaire, Saba and St. Eustatius became ‘special municipalities’ of the Netherlands, making the Dutch government responsible for the implementation and adherence to several international conventions that apply to these islands (e.g. Convention of Biological Diversity, Ramsar convention), including the protection of nature.

Knowledge on the whereabouts of endangered and key species or habitats is essential to ensure their protection against the negative effects of activities such as uncontrolled socio-economic developments (e.g. construction works, harbour expansion, expansion of residential areas) and natural phenomena (e.g. hurricanes, Sea Level Rise). This necessitates early identification of risk locations where future expected activities may collide with species/habitat presence. To determine these whereabouts, monitoring is necessary. Monitoring in the field, however, is often costly and time-consuming. A more effective and quicker approach is desired to obtain a realistic overview of key habitat distributions and associated key species.

At the request of the Dutch Ministry of Economic Affairs the present study examines the possibility to identify the different land cover types (natural and artificial) on Very High Resolution1 satellite images of the Caribbean islands Bonaire, Saba and St. Eustatius, using remote sensing1 analysis. In addition, the possibility to link key species with specific land cover types was assessed by identifying the species’ habitat requirements. Linking species habitat requirements with associated land cover types allows for the identification of their potential occurrence on the islands. It was expected that with niche-modelling potential distribution maps could be developed for different species and habitats. Such maps are valuable to determine risk locations where species/habitat occurrence and planned activities may conflict in the future. This would allow for the proper and early implementation of protective measures.

Worldview-2 satellite images of Saba and St. Eustatius (acquired on 3 December 2010 and 18 February 2011, respectively) were analysed. Analysis of the satellite image of Bonaire was not possible, due to time constraints. From the results of Saba and St. Eustatius it can be concluded that identification of land cover types using satellite images is possible. At present, the results are limited due to a) heterogeneous land cover types and b) the lack of ecological knowledge (e.g. baseline studies).

The identification of artificial features1 (e.g. infrastructure) is not a problem. The challenges encountered are mainly related to the largely mixed heterogeneous vegetation found on Saba and St. Eustatius. Due to the high level of mixing, spectral overlap between different vegetation types is high. Consequently, separating the different vegetation types is difficult. Corrections can be made based on visual interpretation and expertise in the field. This requires time and expert knowledge of the different vegetation types. In addition, both Saba and St. Eustatius exhibit strong differences in altitude, resulting in numerous shadowed areas that impede the identification of the land cover types underneath. Such terrain effect can be corrected using a Digital Elevation Model (DEM). Unfortunately, a sufficiently good DEM (with a high spatial accuracy of around 1 meter) was not yet available2.

Analysis of satellite images resulted in land cover maps with good fit to the distribution of the different land cover types on Saba and St. Eustatius. The produced land cover maps (Figures 4 to 7) give a coarse representation of the distribution of Forest, Shrub, Pasture and Artificial surface on the islands. In addition, it was possible to identify the extent and location of invasive vegetation (e.g. Corallita and other species), although identification to species-level was not possible. At present, these maps provide insufficient detail for biodiversity monitoring, because of the lack of connection with species. They could, however, be used to monitor different land cover development (e.g. forestation, artificial surfaces, shrub and pastures) on the long term (e.g. in years) or to gain a quick overview on the location of invasive vegetation. A distinctive land cover classification based on the available satellite images during the present study, however, was only achieved for the coarser vegetation types.

Ecoprofiles were developed for various species and habitats, describing their habitat requirements. With sufficient detail, these requirements link the species to habitats and thereby allow for the creation of species specific maps. The level of available data on habitat requirements varies per species. Overall knowledge on habitat requirements is generally not sufficient, associating species with multiple habitat types, and making it difficult to pinpoint essential habitat types. The amount of knowledge on habitat requirements has direct influence on the success of niche modelling. This illustrates the necessity of detailed knowledge on species biology, ecology and life history characteristics even when using advanced techniques such as remote sensing.

The production of maps through niche-modelling meant to show the expected geographical distribution of species was not possible due to the limited level of detail within the identified land cover types, and the restricted data on the habitat requirements of the species occurring on Saba and St. Eustatius, in combination with time constraints. Before such maps can be developed several issues need to be solved first. These include specific knowledge on species biology, ecology and life history characteristics of the target species (baseline studies); the collection of more training samples (ground truthing data) in the field; a high quality DEM of Saba and St. Eustatius (and Bonaire as well). This will lead to further adaptation of the chosen classification scheme and aid in separating spectral overlap between the different vegetation types.

This research is part of the Wageningen University BO research program (BO-11-011.05-019) and was financed by the Dutch Ministry of Economic Affairs (EZ) under project number 4308701012. 

Date
2013
Data type
Research report
Theme
Research and monitoring
Report number
C124/13
Geographic location
Saba
St. Eustatius

Saba Bank research expedition 2011 – Progress Report

Abstract:

The Saba Bank is a large submerged carbonate platform of approximately 2,200 km2 in the Caribbean Sea which lies partially within the Exclusive Economic Zone of the Netherlands and partially within the territorial waters of Saba and St. Eustatius. It was declared a protected area by the Dutch Government on 15 December 2010 and has been registered as such in the Specially Protected Areas and Wildlife (SPAW) protocol of the Cartagena Convention for the Protection and Development of the Marine Environment of the Wider Caribbean. Applications for a Particularly Sensitive Sea Area (PSSA) at IMO and Ecological or Biological Significant Area (EBSA) at CBD are pending.

As part of the Saba Bank research program 2011-2016, commissioned by the Dutch Ministry of Economic Affairs (EZ), an expedition to the Saba Bank was conducted from 22 to 29 October 2011. The Saba Bank research program aims to obtain information on the biodiversity, key ecological processes and carrying capacity for commercial fisheries to facilitate sustainable management of the area. The primary objectives of the 2011 research expedition were to collect data on benthic and reef fish communities; sponges and nutritional sources of the sponge community; seabirds and marine mammals; water quality, water velocity and other physical parameters. A multidisciplinary team conducted video and visual surveys on benthos, fish and sponges during 10 SCUBA dives at 20-30m depth, while sea birds and marine mammals were surveyed by means of on-board visual surveys and acoustic data loggers. Water velocity and water quality were also measured on-board using an Acoustic Doppler Current Profiler (ADCP) and Conductivity, Temperature and Depth (CTD) device.

During the expedition 8 sponge species were collected and 37 scleractinian coral species and 85 fish species were identified.Fish biomass varied per site between 1.3 kg to 4.4 kg.
Part of the measurements on water velocity, water quality and benthic cover are still in the process of being analysed. Data collected will also be used as baseline for future monitoring and analyses of biodiversity and key ecological processes within the framework of the 2011-2016 research program. 

Date
2013
Data type
Research report
Theme
Research and monitoring
Report number
C018/13
Geographic location
Saba bank

Towards a predictive model supporting coral reef management of Bonaire’s coral reef. Progress report 2012.

Date
2013
Data type
Research report
Theme
Governance
Research and monitoring
Report number
C070/13
Geographic location
Bonaire

A status report of nature policy development and implementation in the Dutch Caribbean

The National Nature Policy Plan 2001-2005 (NPP-5) and its current status of implementation was assessed as a first step towards a new Nature Policy Plan for the Caribbean Netherlands (Bonaire, Saba, St. Eustatius). The purpose of this exercise is to determine which action points of NPP-5 are still relevant, and to identify key new developments to be aware of when setting goals and strategies for the new Nature Policy Plan for the Caribbean Netherlands. The NPP-5 was the first formal nature policy plan of the Netherlands Antilles. It lists a total of 47 policy goals and projects in the text for the period 2001-2005. Based on these, 61 action points were listed in an Action Matrix for the period 2001-2005. Of these 31 were achieved to a high degree of completion between 2001 and 2010, notwithstanding the serious and chronic lack of both funds and manpower (NEPP-7). Based on this assessment, a total of 40 action points may be brought forward based on the NPP-5. These not only include most “one-time” action points not yet achieved but also several action points that were achieved but which are of an on-going nature.

While much has been achieved in terms of policy development and legal frameworks over the last 10 years, climate change implies that future nature management will be confronted with an increasingly rapid succession of major ecological problems such as coral bleaching, hurricane impacts, and invading species.

Our quick-scan assessment showed that policy development over the last 10 years has suffered significantly from challenges in terms of both capacity and funding, as well as in decision-making in reaching its goals. Controversial topics regarding “rules and regulations”, “cooperation”, and “financial instruments” largely failed to be achieved due to problems in the decision making process, whereas less controversial action points such as “reporting”, drawing up “plans”, doing “research” and “education”, especially suffered from a lack of capacity and funding.

Several main topics are identified that will need attention in the new nature management plan. The new nature policy will have to meet standard and basic policy needs, information and management needs, and also have to accommodate the latest conceptual developments and the pressing realities of global climate change and alien species invasions. Notable is that a large number of new and serious threats have come to the forefront since the NPP-5 was set 10 years ago.

Because the diverse, colourful and unique natural ecosystems of the Caribbean Netherlands also represent the single most important local economic resource on which to build long-term prosperity of the inhabitants of these islands, the nature policy plan needs to be recognized as much more than simply a way to protect nature and avert ecological crisis. It is in fact a key policy tool by which to actively safeguard and create economic well-being and opportunity for these islands.

Date
2011
Data type
Research report
Theme
Governance
Report number
C065/11
Geographic location
Saba

A status report of nature policy development and implementation in the Dutch Caribbean over the last 10 years and recommendations towards the Nature Policy Plan 2012-2017

The National Nature Policy Plan 2001-2005 (NPP-5) and its current status of implementation was assessed as a first step towards a new Nature Policy Plan for the Caribbean Netherlands (Bonaire, Saba, St. Eustatius). The purpose of this exercise is to determine which action points of NPP-5 are still relevant, and to identify key new developments to be aware of when setting goals and strategies for the new Nature Policy Plan for the Caribbean Netherlands. The NPP-5 was the first formal nature policy plan of the Netherlands Antilles. It lists a total of 47 policy goals and projects in the text for the period 2001- 2005. Based on these, 61 action points were listed in an Action Matrix for the period 2001-2005. Of these 31 were achieved to a high degree of completion between 2001 and 2010, notwithstanding the serious and chronic lack of both funds and manpower (NEPP-7). Based on this assessment, a total of 40 action points may be brought forward based on the NPP-5. These not only include most “one-time” action points not yet achieved but also several action points that were achieved but which are of an on-going nature.

While much has been achieved in terms of policy development and legal frameworks over the last 10 years, climate change implies that future nature management will be confronted with an increasingly rapid succession of major ecological problems such as coral bleaching, hurricane impacts, and invading species.

Our quick-scan assessment showed that policy development over the last 10 years has suffered significantly from challenges in terms of both capacity and funding, as well as in decision-making in reaching its goals. Controversial topics regarding “rules and regulations”, “cooperation”, and “financial instruments” largely failed to be achieved due to problems in the decision making process, whereas less controversial action points such as “reporting”, drawing up “plans”, doing “research” and “education”, especially suffered from a lack of capacity and funding.

Several main topics are identified that will need attention in the new nature management plan. The new nature policy will have to meet standard and basic policy needs, information and management needs, and also have to accommodate the latest conceptual developments and the pressing realities of global climate change and alien species invasions. Notable is that a large number of new and serious threats have come to the forefront since the NPP-5 was set 10 years ago.

Because the diverse, colourful and unique natural ecosystems of the Caribbean Netherlands also represent the single most important local economic resource on which to build long-term prosperity of the inhabitants of these islands, the nature policy plan needs to be recognized as much more than simply a way to protect nature and avert ecological crisis. It is in fact a key policy tool by which to actively safeguard and create economic well-being and opportunity for these islands. 

Date
2011
Data type
Research report
Theme
Governance
Report number
C065/11
Geographic location
Bonaire
Saba
St. Eustatius

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

Lac Bonaire - Restoration Action Spear Points, September 2010

Lac Bay, Bonaire is the most important mangrove and seagrass area of Bonaire and has been undergoing steady ecological decline in the last decades. Based on an initial assessment of conservation management issue and potential solutions, as, conducted by IMARES in June 2010, the Dutch Ministry of Agriculture, Nature and Food Quality (LNV) asked IMARES to return to Bonaire to work with Stinapa Bonaire to choose narrower priorities and jointly make a short-list of topics as a working document for cooperation and action. In the beginning of September, site visits and discussions were held in Bonaire with the manager of Lac Bay and various stakeholders to identify and agree on priority issues for action. This working report gives the results of that visit.

Four action spear point projects were identified, based on urgency and feasibility based on local Bonaire and Dutch IMARES expertise. The projects are as follows:

1. Mangrove restoration demonstration pilot study
The basic objective is to reestablish water depth and tidal connection in high marsh salt areas that have resulted from infilling with sediment, and restore them as effective mangrove and low marsh fish nursery habitats. By collecting baseline data before the restoration activities take place, it will be possible to monitor and compare and assess changes in fauna and flora at the restoration sites and hence evaluate the effectiveness of the measures implemented.

2. Baseline ecological study of the zonation of aquatic communities
The goal is to complete a scientific description of Lac’s aquatic community zonation as it exists at landscape level today. This will provide the framework against which large-scale community change and effectiveness of mitigation measures can be monitored and evaluated.

3. Recreational and land use survey for Lac Bay and its catchment area
The goal is to identify user problems and potential solutions by mapping and assessing user density and pressures in Lac

4. Study of avifaunal habitat use of Lac Bay
The goal is to identify bird habitat use problems and potential solutions by assessing habitat use of Lac by birds during the migratory season.

(A fifth project for implementation by Stinapa and Dienst LVV was identified)
5. Lac mangrove channel clearing project
Re-establish water flow from the Bakuna dam to Lac using a pipe system.

The Lac mangrove channel clearing project of Stinapa was reviewed and judged to be valuable and important. The baseline study of zonation of aquatic communities (project 2) is urgently needed in this respect to allow short and long-term evaluation of this project which need to become a structural part of Lac Bay management. Routine mangrove channel maintenance was identified as ideal work for involvement of Bonaire youths and volunteers, to rekindle public involvement in caring for Lac and its rich natural and cultural-historical heritage. 

Management Recommendations:

A project plan is presented by which all four projects can be delivered by December 2012. These projects can count on government and broad community support. In this all, Stinapa indicated to be willing to provide basic free lodging to interns and scientists at their science accommodations at the entrance of Washington-Slagbaai National Park. The ability and willingness of IMARES to recruit and guide students and interns for these projects was an important selection criterion to help restrain total project costs. The action spear points will, nevertheless, require funding as well as permits from the Island Government of Bonaire. With LNV various funding options were reviewed and discussed, and the need for permits was discussed with DROB (Dienst Ruimtelijke Ontwikkeling en Beheer) Bonaire. DROB envisioned few problems with the required permits. The visit was concluded by the joint resolve to work out ways to maintain momentum and proceed towards the implementation phase.

Date
2010
Data type
Research report
Theme
Governance
Education and outreach
Research and monitoring
Report number
C131/10
Geographic location
Bonaire

Towards sustainable management of the Saba Bank

Findings:

The main conclusion from this study is that the Saba Bank is particularly important for several reasons:

  • It is an important and unique ecosystem in relatively pristine condition.
  • The coral reefs of the Saba Bank are relatively remote from intense human impact and may not only provide important scientific information on the status of reefs in relatively unspoiled condition, but are also a reserve of biodiversity for the region.
  • It has potential for increase in economic importance: the reefs of the Saba Bank are potentially a resource for dive-tourism and an essential resource for fishing.
  • It is of considerable economic and social importance.

Some important findings of the study are listed below:

Biodiversity

  • The total surface area of the Saba Bank is about 2200 km2.
  • Extensive coral reefs can be found along large parts of the edge of the Saba Bank. The reefs appear healthy and support a rich biological community.
  • Saba Bank constitutes the largest actively growing atoll in the Caribbean and possibly the third largest atoll in the world.
  • Saba Bank forms a regionally unique ecosystem that is relatively pristine, characterized by high biological diversity and productivity.
  • The Saba Bank is likely a source of fish and coral larvae, supporting the coral reefs of islands in the region.

Use

  • The primary users of the Saba Bank are the fishermen from Saba. Fishermen from neighboring Caribbean islands also fish on the Saba Bank. The waters over the bank are also used for passage by oil tankers, freighters, cruise ships. Some tankers anchor on the bank while waiting for permission to enter St. Eustatius' harbour.
  • Overfishing and anchoring were distinguished as having (potentially) the most severe effects on the Saba Bank and its resources
  • Presently, economic benefits are only derived from fisheries. Additional benefits could be generated through diving and sport-fishing on the Bank.

Legislation

  • New regulations (e.g. National Law Nature Conservation and Protection, National Law on Environmental Management, National Law Maritime Management) are in the process of becoming legislation. Combined with an effective coast guard, these laws should enable the Netherlands Antilles to manage the sustainable use of the natural resources of the Saba Bank.

Management Recommendations:

  • Develop a management plan to preserve this unique marine habitat.
  • The creation of an exclusive fishery zone that completely encloses the Saba Bank would offer the Netherlands Antilles ample opportunity to regulate harvesting of the Saba Bank's natural resources.
  • The installation of an Exclusive Economic Zone (EEZ) would further increase the opportunities for management.
  • Fill in the main gaps in knowledge, which include information on reef and species distributions, data on major ecological processes, ship anchoring and traversing frequency, use of the bank by other islands and most importantly stock and catch data of commercially used species.
  • An integrated management approach of Saba Bank is recommended because it better addresses the problems inherent to a multi-use area.
Date
1996
Data type
Research report
Theme
Research and monitoring
Report number
KNAP Project 96-03
Geographic location
Saba bank

Biodiversiteit voor de BES-eilanden: Bonaire, St. Eustatius en Saba: onderzoeksvragen en verplichtingen

Date
2010
Data type
Research report
Theme
Governance
Research and monitoring
Report number
C117/10
Geographic location
Bonaire
Saba
St. Eustatius