The parrotfish Sparisoma viride is an abundant and ecologically important member of the tropical NW Atlantic reef fish fauna. Sagittal otoliths of 417 individuals were analysed to estimate age-based demographic variables at 4 localities (Lee Stocking Island, Barbados, Los Roques Archipelago and the San Blas Archipelago) spanning 14° of latitude. The sampling localities ranged from an area protected from trap- and net-based reef fisheries (Los Roques) to an area supporting a dense human population and sustained trapping and spearing for reef fishes including S. viride (Barbados). Examination of sectioned sagittal otoliths from each locality revealed regular increments in the sagittal matrix. A preliminary validation at San Blas was consistent with these increments being annual check marks. These increments provided estimates of age structure, maximum longevities and mortality rates for the 4 study populations of S. viride. Von Bertalanffy growth functions fitted to each size-at-age plot generated similar growth curves from 3 of these 4 localities. The exception was Lee Stocking, where fish grew faster and reached a substantially larger size than those from the other 3 localities. Further analysis of the growth curves demonstrated that the differences between Lee Stocking and the other localities were attributable to more rapid growth over the first 4 yr of life. Age-based growth curves derived from the Los Roques population were very similar to a size-based curve generated by an independent study on S. viride carried out in Bonaire, adjacent to Los Roques. Maximum longevities for all 4 of our populations varied from 7 to 9 yr. Mortality rates generated from catch curve analysis were also similar among localities and suggest that maximum life spans do not exceed 12 yr. This result differs from that obtained at Bonaire, where repeated censuses of tagged fish suggest 30 yr maximum longevity. Abundances of S. viride varied 3-fold among localities, being highest at Los Roques (protected from reef fishing), lowest at Barbados (high fishing) and Lee Stocking (low fishing). Thus our age-based study suggests that S. viride is a relatively short-lived fish with consistent demographic parameters over a range of localities, latitudes and fishing intensities.
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.
The aim of the present project–commissioned by the management of the Washington-Slagbaai Park (WSP)- was to set-up a more strategic management of the natural elements of this protected area.
The results are presented in three sections: I. Rare plant species; II. Exclosures and III. Monitoring. The survey of the rare plants resulted in the discovery of three plant species not previously known for Bonaire: Capparis linearis (a tree), Adiantum capillus-veneris (a fern) and a yet undetermined Thelypteris sp.( (a fern). Occurrences were also documented for rare species already known to occur in the WSP. The survey also led to the rediscovery of Capparis tenuisiliqua for the WSPand Bonaire. Brassavola nodosa is reported for the first time for the WSP.
The search for rare plants took place on a number of the higher hills in the WSP. The ‘Matadó di Pasku’ was the hill with the most rare plant species (15). Most of the higher hills in the WSP have a number of denuded areas or areas with scanty vegetation. This is the result of vegetation and soil degradation caused mainly by goat grazing. The negative impact of these animals is also reflected in the almost complete absence of seedlings or other stages of rejuvenation of the rare plants and the exclusive occurrence of the orchid Brassavola nodosa on rock boulders at inaccessible heights for goats.
Isolation of vegetation results in reduction of its dispersal capabilities. As a way to counteract this it is recommended to fence off small areas around the rare tree species identified during the survey. A number of indigenous plant species have been identified that should receive priority in a monitoring and recovery plan: Capparis tenuisiliqua, C. linearis, Schoepfia schreberi, Maytenus tetragona, Eugenia procera, Myrcia curassavica, Psidium sartorianum and Celtis iguanaea. A monitoring protocol is presented to aid in the collection of the data. It has also been recommended to start a propagation program for the orchid species B. nodosa and Schomburgkia humboldtii. The latter was reported in a botanical study in 1994 and must occur in small numbers but could not be relocated. While Sideroxylon obovatum, Guapira fragans and G. pacurero were considered rare in a botanical study done in the WSP in 1994 we did not consider these species rare because they occur quite frequently on the hills visited and are also found in other areas of the island. The results of the present study indicate that it would be valuable to have a botanical survey done of the higher hills of the WSP that could not be visited in the present study.
Three exclosures (9 x 9 m) and three adjacent control plots of the same size (accessible to goats, donkeys and pigs) have been established in the dominant Casearia-Prosopis vegetation type of the D3 landscape type of the WSP. Data collection took place in nine sub-plots of 3 x 3 for both the exclosures and adjacent control sites. The control site was the area of which the vegetation most resembled the vegetation inside the exclosure.
TL7 was the second landscape type in which exclosures and control sites were established. TL7 was chosen above the second most frequent landscape type (D2) of the WSP because its exclosures will provide insight into the development of limestone vegetations and effects of introduced animals (mammals) on them. Limestone vegetations are characterized by dominance of (semi-)evergreen plant species. The sample plots surveyed are characterized by a low number of plant species and high incidence of goat dung pellets.
It is recommended to repeat the data sampling of the exclosures and control sites in two years order to gain insight in the short-term changes in the different vegetation types. Longer-term changes will be seen over a number of years.
To gain a broader insight in natural vegetation development (which will also help to understand development in animal communities) it is necessary to establish several 50 x 50 m permanent plots in (at least) the two most dominant vegegation types in the WSP: Casearia-Prosopis type (D3) and Croton-Haematoxylon type (D2). Because the Slagbaai area will be the first part of the WSP where the goats will be removed, these plots should be placed in this part of the WSP. A data sheet to aid in the data collection (developed by ITC) is presented. A total understanding of the natural development of the vegetation of the whole WSP will be possible through the making of a detailed vegetation map (scale 1:10,000-1:25,000) and repeating it after 20 -30 yrs.
Only one bat species (Glossophaga elongata) is found in the two caves and a well in the WSP. A monthly monitoring program of especially the cave on Seru Grandi is needed in order to determine its significance for G. elongata and possibly other bat species occurring on Bonaire. The easily accessible small cave at Slagbaai should be fenced off to prevent unnecessary disturbance of the bats roosting there by visitors of the WSP.
The monitoring top priorities for bird species are: Buteo albicaudatus, Amazona barbadensis, Sterna hirundo, S. antillarum and Phoenicopterus ruber. Monitoring methods are presented for these species.
No data is available on the impact of exotic plant species in the WSP, but it must be low because invasives were not recorded in any of the sample plots from the park used for the production of the vegetation map of the island and Cryptostegia grandiflora was only seen on the Juwa. In order to be able to control the impact of these species (Cryptostegia grandiflora, Leucaena leucocephala, Azadirachta indica and Jasminum fluminense) they should be monitored. Deleterious exotic animals causing damage in the park at present include goats, donkeys, pigs, cats and dogs. These should be controlled and monitored also. It is therefore recommended to make it a duty of the WSP rangers to report on plant or animal exotic species seen during their patrols and fieldwork. A design for a simple monitoring protocol to record and monitor exotic species is presented. A quick assessment by a biologist of the level of presence of exotic plant species in the WSP will help form the basis of such a program for the exotic plant species and determine the necessary level of interventions by park management. At present there is a trapping program for goats in place using a number of fenced off areas in Slagbaai.
Among the group of remaining animal species three species have been indicated as indicator species for monitoring: Poecilia vandepolii (euryhaline fish), Gecarcinus ruricola (land crab) and Phoebis agarithe (butterfly).
Six habitat types have been distinguished in the WSP: Cave systems, salina habitat, freshwater habitat, vegetation types of Washikemba formation, vegetation types of limestone formations and beach landscape. Their characteristics, occurrences in the WSP, importance for the survival of native fauna and flora species and management and monitoring options are given for these habitat types.
A preliminary inventory is given of key terrestrial nature values of Bonaire in order to determine their occurrence in relation to areas designated as “nature” and “open landscape”, according to the Spatial development plan of Bonaire. This was based on a literature study and supplemented by expert advice.
In 2010 a spatial development plan was written in order to determine the spatial policy and regulation for the future development of Bonaire. The island was partitioned into areas for different uses such as agriculture and recreation. Two specific designations are “nature” and “open landscape”. The occurrence of nature values within these areas remained unclear. This makes implementation of protective measures based on international treaties and island legislation problematic. An inventory of the occurrence of these values should help facilitate more effective implementation of these protective measures. In the present study key nature values are determined, both in terms of protected species and essential habitat (e.g. caves).
From the literature study it became apparent that data on the occurrence of most of the priority species of flora and fauna, is limited and scattered, especially with respect to “open landscape” and “nature” outside parks. Therefore, only a preliminary inventory is provided showing the general distribution of nature values across the entire island, as linked to various habitat types. An exact distribution of the different nature values was not possible at this time, but extrapolation from areas of known occurrence into other areas of similar habitat type was used to show the occurrence of overlapping distributions of nature values within the designated areas of “nature” and “open landscape”. The number of overlapping distributions of nature values may contribute to setting conservation priorities.
From the results it can be concluded that the areas of “open landscape” and “nature” (outside the national parks) seem to harbour unique and critical nature values. These areas are not actively managed or protected as national parks. The “open landscape” of Bolivia possibly harbours a few rare plant species (unique), an important population of critical key columnar cacti and at least two columnar cactus-pollinating bat species. The “open landscape” of Washikemba/Bakuna harbours key mangrove species that only have another main location at Lac Bay (national park). The “nature” area of Terrace Landscape Middle Bonaire seems to harbour a concentration of unique (e.g. Tillandsia balbisiana) and rare plant species (e.g. Krugiodendron ferreum etc.) and four bat species. The same is the case for Lima (e.g. Sabal palm, Maytenus versluysii and three bat species) while in Southern Bonaire key mangrove species also still occur. Table 1 shows which nature values are found or expected to occur within each “open landscape” and “nature” (outside national parks) area.
It can be concluded that outside the current parks, the main regions that harbour a concentration of key nature values are Terrace Landscape Middle Bonaire/Sta. Barbara, Bolivia, Washikemba/Bakuna and Lima. Terrace Landscape Middle Bonaire is designated as “nature” area, while Washikemba/Bakuna and Bolivia are in part designated as “open landscape”. Lima has both “nature” and “open landscape” designations. Sta. Barbara is designated for other uses, but the present review shows that the occurrence of several significant nature values is likely within this area.
Additionally, based on the preliminary inventory, the combination of apparent concentrations of rare plants, occurrence of critical bat species and the high probability of corridor values show that the areas of Terrace Landscape Middle Bonaire/Sta. Barbara and Lima are important areas concerning conservation and further research. The areas of Bolivia and Washikemba/Bakuna follow closely.
To be able to implement the necessary protective measures within these areas, it is recommended that more extensive research through fieldwork is done, in order to obtain a complete inventory of the different nature values found on Bonaire, not only in the areas of “nature” and “open landscape” but also in areas with other designations. Additionally, it is recommended to assess the list of vulnerable and endangered species (‘Informatieblad beschermde dier- en plantensoorten Bonaire’) as certain species that may be of importance to Bonaire are not included.
When executing a complete and extensive inventory of Bonaire it would be of value to also determine the ecological conditions needed for the different species to survive. Based on the ecological conditions necessary for their life functions, it may be possible to pinpoint those areas of main ecological importance per species. A complete inventory of the nature values on the island can contribute to better management of nature values (e.g. determining the distribution of caves and the distribution, health status and diversity of keystone cacti species for better management of bat populations). It is also recommended to determine areas with high potential for the occurrence of rare or relict species and which areas harbour high corridor values.
For future research it is recommended to execute a complete and extensive inventory of Bonaire, through fieldwork, in order to implement the necessary protective measures to ensure the conservation of these nature values. The present study shows that the areas of WNSP/Brasil, Terrace Landscape Middle Bonaire, Lima and Bolivia may be of priority as these areas seem to harbour a concentration of unique and critical plants.
Present studies shows that key nature values may occur in areas with a different designation than “nature” or “open landscape”. For future research it is recommended not to limit inventory research to the areas of “nature” and “open landscape”, but to include other areas with different designations.
In the present study the nature values chosen were based on the list of vulnerable and endangered species (Informatieblad beschermde dier- en plantensoorten Bonaire). During the study several species were added based on expert knowledge. The list used therefore seems to be limited. For future research it is recommended to assess if there are other nature values that are important to Bonaire that should be included on the list (e.g. Clusia sp, Ammodramus savannarum).
A complete inventory of the nature values on the island can contribute to the better management of nature values. A good example is the management of Bonaire’s bat population. In order to define the priority areas to maintain for the management of the different bats on Bonaire it is essential to obtain a detailed inventory of the different caves that these species use as habitat.
Additionally for the nectar-feeding bats it is crucial to map the occurrence of the different candle cacti on which they feed. The nectar-feeding bats are the critical pollinators of the three candle cacti (Petit, 2001). As already mentioned these cacti are key species on the island as they provide food for several species of animals during the dry season, when many other plant species are non-productive (Petit, 2001). Research on the distribution, health status and diversity of candle cacti on Bonaire is recommended in order to pinpoint priority areas for nectar- feeding bats. The cactus populations are threatened severely by feral livestock (goats, donkeys) which remove the bark of the mature trees, thereby threatening the food supply for frugivores and nectarivores. From our analysis open land areas of Bolivia would seem to possess large cactus populations of vital interest to conservation of endangered bird species on an island-wide scale.
When executing a complete and extensive inventory of Bonaire it would be of value to determine the ecological conditions and various habitats needed for the different species to survive. Based on the ecological conditions necessary for their life functions it may be possible to pinpoint those areas of principal ecological importance per species.
It is necessary to identify those areas with a high potential for the concentration of nature values rare species or relict vegetation species in order to secure the survival of these species and to be able to implement the necessary protective measurements. Such areas for instance are the open land and nature sections of Lima, Terrace Landscape Middle Bonaire (nature) and Bolivia (open). For future research it is recommended to determine those areas with high corridor values for the implementation of ecological corridors and buffer zones on Bonaire.
The invasion by lionfish Pterois volitans and P. miles throughout the western Atlantic and Caribbean is emerging as a serious ecological problem. While lionfish have been identified on coral reefs and in other marine systems, additional ecosystems may be affected as the invasion spreads. Here we identify the first estuarine intrusion by lionfish in their invasive range. Lionfish (n = 211) were captured in the Loxahatchee River estuary (Florida, USA) between August 2010 and April 2011, with some individuals located as far as ~5.5 km from the ocean. Multiple size classes were documented (standard lengths ranged from 23 to 185 mm), and post-settlement juveniles were present throughout the sampling period. All individuals were found in close association with anthropogenically created habitats (e.g. docks, sea walls, submerged debris), suggesting that humandriven changes in habitat availability may facilitate estuarine invasion. Fifteen prey taxa were found in lionfish stomachs, with diets dominated by small shrimp. Since estuaries are already highly threatened by human impacts, and provide critical habitat for numerous commercially, recreationally, and ecologically important species, establishment of lionfish in these ecosystems is of particular concern
In October 2011 an expedition took place to the Saba Bank, on board of the ship the Caribbean Explorer II. Main aim of the expedition was collecting data on underwater fauna and coral reefs. Apart from that data were collected on nutrients, water flow, sponges and seabirds and marine mammals. Data on the last group were collected by deploying acoustic data loggers, and by means of visual surveys. These visual surveys were conducted whenever the other activities permitted it. This cruise report presents an brief overview of the results obtained during the October 2011 survey. It contains a short day to day report, a full list of all birds, mammals and particular pieces of floating matter seen, and a brief presentation of the results. Furthermore the report contains a brief account of observed birds on Sint Maarten, since published accounts on the birdlife of the island are scarce.
- The seabirds most often spotted were the Brown Booby and the Magnificent Frigatebird.
- No marine mammals were observed.
- Red-Billed Tropicbirds were primarily spotted near the shore of Saba.
Birds on Sint Maarten
The first ever records of the following birds were made during this expedition:
- Cinnamon Teal (possibility of a hybrid cannot be excluded).
- Marbled Godwit (flying over the Great Salt Pond).
- A Merlin was seen hunting amongst Cliff Swallows and Barn Swallows.
- Three Ospreys were recorded.
- Breeding Caribbean Coots or adults with chicks were seen at several small ponds and in the salines.
Most Common (sighted>10)
- Cattle Egret (Bubulcus ibis)
- Snowy Egret (Egretta thula)
- Magnificent Frigatebird (Fregata magnificens)
- Brown Pelican (Pelecanus occidentalis)
- Black-necked Stilt (Himantopus mexicanus)
- Spotted Sandpiper (Actitis macularius)
- Carib Grackle (Quiscalus lugubris)
- Bananaquit (Coereba flaveola)
Least Common (sighted<2)
- Merlin (Falco columbarius)
- American Oystercatcher (Haematopus palliatus)
- Wilson's Plover (Charadrius wilsonia)
- Short-billed (Dowitcher Limnodromus griseus)
- Wilson's Snipe (Gallinago delicata)
- Marbled Godwit (Limosa fedoa)
- Whimbrel (Numenius phaeopus)
- Solitary Sandpiper (Tringa solitaria)
- Lesser Black-backed Gull (Larus fuscus)
- Cabot's Tern (Thalasseus acuflavidus)
- Eurasian Collared Dove (Streptopelia decaocto)
- Rose-ringed Parakeet (Psittacula krameri)
- Yellow-billed Cuckoo (Coccyzus americanus)
- Green-throated Carib (Eulampis holosericeus)
- Antillean Crested Hummingbird (Orthorhyncus cristatus)
- Northern Parula (Parula americana)
- Caribbean Elaenia (Elaenia martinica)
- Pearly-eyed Thrasher (Margarops fuscatus)
- House Sparrow (Passer domesticus)
- Northern Parula (Parula americana)
- Blackpoll Warbler (Dendroica striata)
- Prothonotary Warbler (Protonotaria citrea)
The vessel that was used during this survey was not well suited for dedicated seabird and cetacean surveys. However, the gathered data fits in well with the seasonal pattern in observed seabird species and densities described for Guadeloupe for the same time period (distinct dip from August to October). According to Debrot et al, there are few records of cetaceans in October.
Six species of sea turtle nest in the Wider Caribbean Region (WCR). In partnership with more than 120 Data Providers, the spatial database of nesting habitat herein assembled is the most comprehensive for any region of the world, with 1,311 nesting beaches identified in 43 WCR nations and territories, inclusive of Bermuda to the north and Brazil to the south. Because some sites host nesting by multiple species, 2,535 species-specific sites are named. Of these, 77% are categorized in terms of abundance: <25, 25-100, 100-500, 500-1,000, or >1,000 nesting crawls per year. Hawksbill and green turtles are the least known, with 33% and 24%, respecttively, of all known nesting sites associated with unknown crawl abundances.
Large nesting colonies are rare. Nesting grounds receiving more than 1,000 crawls per year range from 0.4% (hawksbill) to 7.0% (Kemp’s ridley) of all known species-specific sites. For any species, roughly half of all known nesting sites support fewer than 25 crawls (fewer than 10 reproductively active females) per year. While some nations are making exemplary progress in identifying and monitoring nesting stocks, consistent sea turtle population monitoring effort is still lacking in most areas and recent data are scarce in some jurisdictions; two archipelagic States (Bahamas, St. Vincent and the Grenadines) and Hispaniola (Dominican Republic, Haiti) have never been completely assessed.
The regulatory landscape is fragmented. Thirty (69.8%) nations and territories prohibit sea turtle exploitation year-around: 29 of 43 jurisdictions mandate indefinite protection (eight of these allow exemptions for ‘traditional’ exploitation), while Anguilla has adopted a moratorium set to expire in 2020. With the exception of the Cayman Islands, legal sea turtle fisheries are based on minimum size limits (by weight or shell length), targeting large juveniles and adults in contradistinction to the best available science on management and recovery.
Threats matrices characterizing a range of risk factors, including those that result in the loss or degradation of critical habitat, reveal that beach erosion, nest loss to predators or physical factors, artificial beachfront lighting, direct exploitation of turtles and eggs, and pollution threaten the survival of sea turtles at their nesting grounds in more than 75% of all WCR nations and territories. With regard to factors potentially hindering population recovery at foraging grounds, more than 75% of Caribbean nations and territories cite pollution, fisheries bycatch, entanglement, coral reef and/or seagrass degradation, and losses to hunters, poachers and natural predators as threatening the survival of sea turtles at sea.
The data collected and assembled will allow for further research and analysis of sea turtle abundance (including population trends at index sites) and habitat use; for example, in conjunction with other datasets to determine areas of high biodiversity or areas in need of urgent protection. The database, archived and displayed online by OBIS-SEAMAP (http://seamap.env.duke.edu/), will be updated regularly and used to establish conservation and management priorities, and to inform and improve policy at national and regional levels. Future goals of the project are to research and incorporate seagrass and coral reef data to determine nationally and regionally significant foraging areas, thus identifying marine areas in need of management attention and contributing to the development of a network of population monitoring programs, including juvenile and adult age classes, at index sites.
Saba Bank is a 2,200 km2 submerged carbonate platform in the northeastern Caribbean Sea off Saba Island, Netherlands Antilles. The presence of reef-like geomorphic features and significant shelf edge coral development on Saba Bank have led to the conclusion that it is an actively growing, though wholly submerged, coral reef atoll. However, little information exists on the composition of benthic communities or associated reef fish assemblages of Saba Bank. We selected a 40 km2 area of the bank for an exploratory study. Habitat and reef fish assemblages were investigated in five shallow-water benthic habitat types that form a gradient from Saba Bank shelf edge to lagoon. Significant coral cover was restricted to fore reef habitat (average cover 11.5%) and outer reef flat habitat (2.4%) and declined to near zero in habitats of the central lagoon zone. Macroalgae dominated benthic cover in all habitats (average cover: 32.5 – 48.1%) but dominant algal genera differed among habitats. A total of 97 fish species were recorded. The composition of Saba Bank fish assemblages differed among habitat types. Highest fish density and diversity occurred in the outer reef flat, fore reef and inner reef flat habitats. Biomass estimates for commercially valued species in the reef zone (fore reef and reef flat habitats) ranged between 52 and 83 g/m2 . The composition of Saba Bank fish assemblages reflects the absence of important nursery habitats, as well as the effects of past fishing. The relatively high abundance of large predatory fish (i.e. groupers and sharks), which is generally considered an indicator of good ecosystem health for tropical reef systems, shows that an intact trophic network is still present on Saba Bank
We report the presence of the invasive Indo-Pacific red lionfish (Pterois volitans) in 23 localities of the Venezuelan coast, southeastern Caribbean Sea. This finding is based on ten specimens collected at Parque Nacional Archipiélago de Los Roques (PNAR, Dependencias Federales), Playa Cal, Caraballeda and Puerto Carayaca (Estado Vargas) and 30 specimens observed in 18 localities of PNAR, Parque Nacional Morrocoy (Estado Falcón), Bahía de Cata, Ensenada de Cepe (Estado Aragua), Puerto Cruz, Chichiriviche de La Costa, Mamo, Catia La Mar, La Guaira, Macuto, Caraballeda (Estado Vargas) and Farallón Centinela (Dependencias Federales). The specimens were collected and observed from November 2009 to June 2010. This is the first published report documenting their occurrence in Venezuela.