Freshwater

Geographic variation in Poecilia Bloch and Schneider, 1801 (Teleostei: Poeciliidae), with descriptions of three new species and lectotypes for P. dovii Günther, 1866 and for P. vandepolli van Lidth de Jeude, 1887

Abstract:

The South American species with the vernacular name "mollies" are analyzed and three new species of the genus Poecilia are described and figured, viz., P. boesemani n. sp. from Trinidad, P. koperi n. sp. from Venezuela and Colombia, and P. wandae n. sp. from Lake Maracaibo. Thirteen species of Poecilia are presently recognized from the northeastern part of South America and adjacent islands, viz., six mollies (including P. vivipara and P. caucana), five micropoeciliids, P. heterandria and the guppy (P. reticulata). Two different populations in both P. koperi and P. wandae are recognized, based on variation in pigmentation. From the type series of P. dovii Günther, 1866 and P. vandepolli Van Lidth de Jeude, 1887 lectotypes are selected. Four subspecies of P. gillii are defined as morphologically distinct and geographically correlated populations.

Poecilia reticulata, P. heterandria, and the micropoeciliids P. bifurca, P. parae, P. picta, P. branneri and P. minima are not considered, whereas P. laurae remains a species inquirendae. A geocline in characters of the species of Poecilia is recorded and a possible evolution is discussed. 

Date
2003
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
Author

A Review of the Freshwater Fishes of Curaçao, with Comments on those of Aruba and Bonaire

Abstract:

Based on a field survey and review of published records, I report the occurrence of 13 species of fishes in fresh waters of Curaçao. Seven species are new or previously unpublished freshwater records for the island.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 Curaçao and prevent migration of native amphidromous fish. The introduced tilapia has apparently reduced the abundance of native species. 

Date
2003
Data type
Scientific article
Theme
Research and monitoring
Geographic location
Aruba
Bonaire
Curacao
Author

Exotic and invasive terrestrial and freshwater animal species in the Dutch Caribbean

We here provide an overview of 72 invasive animals of the terrestrial and freshwater environments of the Dutch Caribbean, eleven of which are no longer present. All invasive animals that are principally agricultural pests and or animal and plant diseases (46 species) are excluded as these are discussed separately elsewhere. The 61 species documented and discussed here as presently living in the wild or semi-wild state on one or more of the Dutch Caribbean islands, amount to 12 exotic mammals, 16 birds, 13 reptiles, 5 amphibians, 2 freshwater fishes, 3 insects, 2 mollusks and 8 exotic earthworms. For most species, the ecology, distribution, status and current impact remains poorly known as few invasive species have been object of directed studies. Some of the most deleterious animal introductions have been mammals, particularly the grazers and the predators, most of which have been introduced in the historical past. Among these, the four key species are grazing goats, the mongoose the cat and the black rat. In most cases, such species cannot be eradicated because they are widespread and firmly established or even kept as livestock. Nevertheless, these species must urgently be controlled in sensitive areas where possible. Our review also shows that many introduced mammals and reptiles are still present in relatively small populations, making eradication still very feasible. Seven species have the status of being native in parts of the Dutch Caribbean but introduced to other parts where they are not native. The most threatening of this last category is the green iguana, as introduced to St. Maarten where it outcompetes and hybridizes with the weaker Lesser Antillean iguana.

The key priorities for successful action against invasive exotic animals are:

  • the control of goats;
  • control of introduced predators (rats and cats) near seabird breeding colonies;
  • eradication of several small populations of exotic mammal predators and reptiles as long as this is possible before the get a strong foothold and spread; 
  • eradication of introduced species from small satellite islands which serve (or served) as seabird breeding habitat.

In addition to such on-island action against species already present, it is critical to prevent further introductions. The most important pathways to focus control on are the container transport of goods, the international trade in pets and the trade in ornamental plants. Two key action points are urgently needed: a) develop the existing legislation and b) invasive species management teams (ISMTs) empowered for action. It is essential that these initiatives be firmly imbedded in a policy framework. The first step ahead in these respects should be to outline an Invasive Species Strategy and Action Plan (ISSAP). However, in the interim, the lack of an ISSAP should not hinder directed critical action at the local level (eg. against goats in the national parks and cats at seabird breeding sites).

This research is part of the Wageningen University BO research program (BO-11-011.05-004) and has been financed by the Ministry of Economic Affairs, Agriculture and Innovation (EL&I) under project number 4308202004. 

Date
2012
Data type
Research report
Theme
Research and monitoring
Report number
C001/12
Geographic location
Aruba
Bonaire
Curacao
Saba
St. Eustatius
St. Maarten