Debrot, D.

Vegetation maps are a primary and essential tool in biodiversity science, conservation, management, and monitoring as well as in land-use management planning. In this study a semi-detailed landscape-based vegetation map (scale: 1: 46,000) is presented for the 34 km2 Dutch half of Lesser Antillean island of St. Martin (St. Maarten). A vegetation map is especially critical in biodiversity context as St. Maarten lies in a key biodiversity hot spot and is habitat to more than 100 regional endemic animal and plant species of which 12 are island endemic species found only on St. Maarten. The map is based on a total of 56 vegetation plots that were sampled in 1999 using a stratified random sampling design and analysed using TWINSPAN cluster analysis. Two hundred and twenty (220) plant species, representing 40 % of the total known flora (544 species), were recorded in the sample plots.

A total of four main and eleven different sub-landscape types were distinguished based on geology, geomorphology and the eleven distinguished vegetation types. The most dominant landscape type was the hilly landscape type for which seven sub-landscapes were distinguished. The 11 vegetation units we describe represent an important decline from the 16 vegetation types distinguished by STOFFERS (1956). Large changes have clearly occurred in the coverage and composition of the vegetation types of the island. Between the early 1950s and 1999 the total coverage of vegetated areas in St. Maarten declined from 67% to 42% representing a loss of 25% of the total vegetated surface of St. Maarten. Five of the vegetation units of STOFFERS (1956) have disappeared beyond recognition. These are: Hippomane woodland, Vegetation of the salt flats, Strand scrub community, Littoral woodland and Vegetation of the rock pavement. While Hippomane woodland has in part likely been lost due to hurricane impacts, most vegetation loss and degradation has been due to massive urbanization and touristic development especially in the lower and coastal parts of the island. As a consequence the vegetation types of the higher and steeper sections of the island have remained among the least disturbed and degraded. Some vegetation units described by STOFFERS (1956) have also disappeared due to actual vegetation regeneration and succession to a more diverse state due to the decline in agriculture and livestock grazing. Goat grazing remains especially high in two of the eleven vegetation types we described (50 – 80 % presence of dung in the study plots). The highest goat presence was recorded in a “new” vegetation unit (type 6) that has developed based on the domination of the invasive plants Leucaena leucocephala (jumbie bean, lead tree) and Antigonon leptopus (coral vine). 

The main threats to the vegetation of St. Maarten we discern based on this mapping project are 1) the massive scale of urbanization and touristic development the island has undergone, 2) continued uncontrolled livestock grazing, 3) invasive plant species, and 4) hurricane impacts. Unless actions are taken to stem the loss of and help restore natural vegetations, we predict that the island will continue to lose its plant diversity, and along with it the fauna which depends on that vegetation. Continued loss of natural vegetation will further exacerbate erosion, loss of freshwater, soil quality and 5 environmental resilience to climate change, as well as sedimentation in the marine environment and the concomitant loss of shallow marine habitats like seagrass beds and coral reefs.

To help prevent this scenario from developing further, we recommend several practical measures: 1) implement land-use planning and designate protected areas to preserve the native flora and fauna, 2) limit and control roaming livestock, 3) legally protect endangered and ecologically critical plant species, 4) connect protected areas by means of ecological corridors, 5) implement measures to control and limit invasive species and 6) implement long-term vegetation monitoring

This report presents an overview of the trends in St Eustatius fisheries based on the fisheries data collected on the island during 2012-2018. The fishery on St Eustatius remains mostly conducted by small open boasts with outboard engines. The number of fishing trips carried out by the fleet increased over 2014 peaking in 2015 with roughly 100 trips per months, and subsequently decreased in the following years to an average of 25 trips per month in 2018. 

The main activity is a lobster fishery using traps, also catching a mix of reef fish. This fishery is responsible for nearly 70% of the lobster landings on St Eustatius. The trend in the annual landings in this fishery broadly follows the trends in the fishing effort, with landings reaching 30 tonnes in 2015 and decreasing to 9 tonnes in 2018. Landings of lobsters from the trap fishery show a strong seasonality with higher landings from September to March, and low landings during June-July. The abundance index (derived by modelling the landings per trip) indicates an overall increase in abundance from 2012 to 2017, and an apparent decrease in lobster abundance in 2018. The average carapace length (CL) shows interannual variations without any specific trend, but is on average 95 mm for females and 102.5 for males. This means that an average of 41% of the lobsters are landed below the legal size limit (95 mm). This problem is especially acute for females of which 56% of the landings are of sublegal size. 

The species composition of the bycatch of reef fish in the lobster traps is very diverse, and is dominated by Acanthuridae (Blue Tang, Doctorfish, Surgeonfish), Ostraciidae (Honeycomb and Scrawled Cowfish) and Serranidae (Coney and Red Hind). The trends in the reef fish bycatch in the lobster traps also followed the trend in effort, with values ranging from 1.7 to 9.9 tonnes caught per year. The biomass index calculated from the catch per trip suggests a decrease in fish abundance between 2014 and 2016 and a small increase thereafter. Length frequency data for the main fish species caught in the lobster traps do not show any notable changes over the period studied. 

The second most important fishing activities after trap fishing are scuba diving and free diving. Both activities catch lobster and fish, but while lobster and fish (mainly Coney, Red hind and Lionfish) are in equal proportion in the landings from scuba diving, landings from free diving are largely dominated by lobsters. The lobster abundance index calculated from the catches per trip in free and scuba diving shows an increase from 2012 to 2016, and a sharp decrease thereafter. This is overall the same pattern as seen in trap-caught lobsters. The difference with the trend in the abundance index calculated based on trap data might be explained by spatial and depth differences in the distribution of the fishing effort between those fisheries. Scuba divers also conduct a fishery targeted on conch, representing roughly 40% of the trips. Estimates of the annual conch landings are very variable, and likely to be fairly uncertain due to the lack of information from logbooks in some years. The mean length of the conch landed appears to be stable over time, at 24.5 cm and 23.7 cm for females and males respectively. 

Next to the traps and diving fisheries, different line fisheries are conducted on St Eustatius. A handline fishery on reef fish produced landings between 0.3 and 4.3 tonnes per year in the period 2014-2017, but with much lower estimates in 2018, mainly due to a drop in effort for this year. Large pelagic fish are also caught by trolling, with landings varying between 0.6 and 2.5 tonnes per year. 

Our main recommendations in terms of both management and research and monitoring are as follows: 

- Improve control of and compliance with lobster size-limit regulations. 

- Develop a FAD fishery management plan as part of a St. Eustatius fisheries development plan. 

- Improve port sampling monitoring and subsampling intensity to cover at least one third of the trips dedicated to each fishing metiér. 

- Conduct a closer study on both the Coney and the Red Hind. Do this by combining more intensive port sampling and fisheries independent studies on the distribution and abundance of these species around St. Eustatius. 

On February 16 2016, an invasive Green Iguana (Iguana iguana) was discovered in a residential area on the island of St Eustatius by STENAPA, the National Parks Foundation. It is not known whether the animal was brought to the island as a pet and escaped or was released, or whether it arrived via cargo ship or other means. However, the discovery of this adult female individual forms a great potential threat to the endangered Lesser Antillean Iguana (Iguana delicatissima), which is native to the island and endemic to the Lesser Antilles. The invasive Green iguana, is causing ecological havoc on other islands in the region as it hybridizes readily with the Lesser Antillean Iguana and is also a powerful competitor for the more docile Lesser Antillean species.

The Green Iguana is already responsible for the extirpation of the Lesser Antillean Iguana on St. Maarten and many other Caribbean islands. It can easily be distinguished from the Lesser Antillean Iguana by its black bands on the tail, longer spines along the back, markings on the body, and large scale below the ear (see photo). In contrast, the Lesser Antillean Iguana which may either be green (female) or grey (male), lacks bands on the tail.

While it is very difficult to eradicate invasive reptiles once they become established on islands, if the species is caught early enough it should be possible to prevent its spread and establishment on St. Eustatius. Thanks to decisive action by the Ministry of Economic Affairs of The Netherlands, local authorities and several collaborating parties have been able to develop and implement a rapid response plan. Most importantly this plan includes three week-long “search and destroy” missions, one of which has just been completed.

A newspaper article and radio and TV presentations were used to involve the public at an early stage. The first search mission targeted an area of 200 radius around the exact location where the Green Iguana specimen was found, as well as the harbor area. Fortunately, and notwithstanding broad support and several helpful tips by the island residents, no more Green Iguanas have yet been found. Two more missions are planned for later this year. All material collected will be sent to international experts for various supporting analyses.

For further information or questions or suggestions please contact: Dr. Adolphe Debrot, project leader, IMARES Wageningen University and Research, The Netherlands (dolfi.debrot@wur.nl)

This report presents an overview of the trends in St Eustatius fisheries based on the fisheries data collected on the island during 2012-2018. The fishery on St Eustatius remains mostly conducted by small open boasts with outboard engines. The number of fishing trips carried out by the fleet increased over 2014 peaking in 2015 with roughly 100 trips per months, and subsequently decreased in the following years to an average of 25 trips per month in 2018.

The main activity is a lobster fishery using traps, also catching a mix of reef fish. This fishery is responsible for nearly 70% of the lobster landings on St Eustatius. The trend in the annual landings in this fishery broadly follows the trends in the fishing effort, with landings reaching 30 tonnes in 2015 and decreasing to 11 tonnes in 2018. Landings of lobsters from the trap fishery show a strong seasonality with higher landings from September to March, and low landings during June-July. The abundance index (derived by modelling the landings per trip) indicates an overall increase in abundance from 2012 to 2017, and an apparent decrease in lobster abundance in 2018. The average carapace length (CL) shows interannual variations without any specific trend, but is on average 95 mm for females and 102.5 for males. This means that an average of 41% of the lobsters are landed below the legal size limit (95 mm). This problem is especially acute for females of which 56% of the landings are of sublegal size.

The species composition of the bycatch of reef fish in the lobster traps is very diverse, and is dominated by Acanthuridae (Blue Tang, Doctorfish, Surgeonfish), Ostraciidae (Honeycomb and Scrawled Cowfish) and Serranidae (Coney and Red Hind). The trends in the reef fish bycatch in the lobster traps also followed the trend in effort, with values ranging from 2.5 to 9.9 tonnes caught per year. The biomass index calculated from the catch per trip suggests a decrease in fish abundance between 2014 and 2016 and a small increase thereafter. Length frequency data for the main fish species caught in the lobster traps do not show any notable changes over the period studied.

The second most important fishing activities after trap fishing are scuba diving and free diving. Both activities catch lobster and fish, but while lobster and fish (mainly coney, red hind and lionfish) are in equal proportion in the landings from scuba diving, landings from free diving are largely dominated by lobsters. The lobster abundance index calculated from the catches per trip in free and scuba diving shows an increase from 2012 to 2016, and a sharp decrease thereafter. This is overall the same pattern as seen in trap-caught lobsters. The difference with the trend in the abundance index calculated based on trap data might be explained by spatial and depth differences in the distribution of the fishing effort between those fisheries. Scuba divers also conduct a fishery targeted on conch, representing roughly 40% of the trips. Estimates of the annual conch landings are very variable, and likely to be fairly uncertain due to the lack of information from logbooks in some years. The mean length of the conch landed appears to be stable over time, at 24.5 cm and 23.7 cm for females and males respectively.

Next to the traps and diving fisheries, different line fisheries are conducted on St Eustatius. A handline fishery on reef fish produced landings between 1.4 and 4.9 tonnes per year in the period 2014-2017, but with much lower estimates in 2018, mainly due to a drop in effort for this year. Large pelagic fish are also caught by trolling, with landings varying between 0.5 and 2.3 tonnes per year.
Our main recommendations in terms of both management and research and monitoring are as follows:
- Improve control of and compliance with lobster size-limit regulations.
- Develop a FAD fishery management plan as part of a St. Eustatius fisheries development plan.
- Improve port sampling monitoring and subsampling intensity to cover at least one third of the trips dedicated to each fishing metiér.
- Conduct a closer study on both the Coney and the Red Hind. Do this by combining more intensive port sampling and fisheries independent studies on the distribution and abundance of these species around St. Eustatius.

This book is intended as a popular picture guide to butterflies and moths of Curaçao, Aruba and Bonaire. It is not designed as a field guide for biologists but is primarily intended to stimulate the interest of young conservationists, amateur naturalists, and the general public. To this end, the text is presented both in English and the native Papiamentu. Papiamentu spelling and usage differs between the three islands. The Papiamentu in this book is based on: Dikshonario Papiamentu – Hulandes, 2nd revised edition, by S. M. Joubert, 1999, and Spèlchèk version 1.0, by Fundashon pa Planifikashon di Idioma, 2001.

The information and photos presented in this picture book are based on studies con- ducted by the authors during the period 1996-2000, two papers of which have already been published in the Caribbean Journal of Science. While this book presents some gen- eral information on butterfly biology, technical information and details have been kept to a minimum and should be sought elsewhere. Useful sources of supplemental informa- tion have been listed under ”Further Reading”. While the focus of this book is on the butterflies, a few striking or colorful moths are also featured. We present here general knowledge, including the current distribution of the species thus far recorded and wel- come additional information.

At present there are no words to distinguish butterflies from moths in the Papiamentu language. Both animals are simply called “barbulètè”. We here follow Simons (1868) and use the terms “barbulètè djanochi” and the term “mòt” to refer specifically to moths. Both are expressions derived from the Dutch language. In the text we use the word “barbulètè” to refer only to butterflies and not moths. For the striking group of moths known as “hawkmoths” in English, we here use the term “barbulètè gabilan”. In Dutch this group is known as the “arrow-tailed butterflies” based on the “horn” or “spine” found on the hind part of the abdomen of the caterpillars of these species.

Local names for butterflies and moths also do not exist in Papiamentu. However, previous studies have shown that assigning relevant common names is essential for butterflies to be recognized and appreciated by the general public. As an aid to the development of an awareness of butterflies in the ABC islands, relevant Papiamentu names have been coined for all species pictured, and are preceded in the text by one or more English common name(s). The Papiamentu names were based on either color or appearance of the butterfly, its (local) host plant or existing English common names. Many English com- mon names were adopted from one of the following sources: Carter (1992), Covell (1984), Gerberg and Arnett (1989), Haxaire (1995), Miller (1992) and Stiling (1986). Species for which no published English common names exist or could be found were given a common name based on the widespread practice of using the species name as a basis for the common name. These species have been indicated by an astrisk. Letters placed between parentheses behing each species’ Papiamentu common name indicate for which of the three islands each species can presently be confirmed by the authors.

Power Point

Vegetation Bonaire

Impact of goats on the original vegetation on Bonaire

Rapport van Wageningen UR waarin een zo onderbouwd mogelijk beeld van de geitenhouderij op Bonaire wordt gegeven

Based on a field survey and review of published records, I report the occurrence of 13 species of fishes in fresh waters of Curacao. Seven species are new or previously unpublished freshwater records for the island. New records are also provided for the adjacent islands of Aruba and Bonaire. Although the native freshwater fish fauna is dominated by predatory gobiid and eleotrid fishes, the most frequently encountered species was the endemic molly, Poecilia vandepolli. The next most frequent species was the native mountain mullet (Agonostomus monticola), followed by the exotic Mozambique tilapia (Oreochromis mossambicus) and the native emerald sleeper (Erotelis smaragdus). High dams block surface water flows in Curacao and prevent migration of native amphidromous fish. The introduced tilapia has apparently reduced the abun- dance of native species.

Report on the assessement of the population density goats on Bonaire