Pachypanchax varatraza
Pachypanchax varatraza ( madagass. Varatraza - East Wind ) is a threatened fish in Madagascar. Its name alludes to the unexpected presence of the species on the eastern slopes of the Tsaratanana massif.
Distribution and habitat
The freshwater fish inhabited by rainforest shaded, plants low in the river basins of the rivers Menambery, Fanambana and Ampanobe in the northeast of Madagascar. His native waters mildly acidic, relatively soft and have only a small conductance.
Appearance
The robust fish can reach a standard length of eight inches, making it one of the larger members of the genus Pachypanchax. His appearance corresponds to the typical habitus of this group. The standing far behind dorsal fin begins on the approach of the ninth and tenth ray of the anal fin. She's wearing in the rear third, a pattern of small dots. Starting from fin base to show the first two thirds of the tail fin is also a pattern of fine dark spots. The pectoral fins are with some 13.4 per cent of standard length, the relative smallest of the Pachypanchax species. The first gill arch bears ten to twelve gills Reuse extensions. There exist only on the males pronounced, a green and a red color form. The scales of the green variant show in the posterior half of the body rusty to chestnut brown corners with their size and intensity is population dependent. The drawing female individuals is less pronounced than that of their male counterparts. P. varatraza contributes 30 to 32 scales along the lateral line (SL).
Fins formula:
- Dorsal II-IV/8-11
- Anal II-III/14-17
- Pectoral 14-16
- Ventral I / 5
Way of life
P. varatraza finds its food both at the surface and on the seabed. It feeds mostly on approach food and aquatic insects and insect larvae. He himself probably represent the Madagascar Kingfisher (Alcedo vintsioides ) and a large goby, Glossogobius giuris after. The reproductive phase is probably quite extensive and lasts the entire rainy season.
Status
In several parts of its original area, the stocks of P. varatraza have now expired. A big threat is the introduced in 1978 in Madagascar snakehead Channa maculata. This neozoon has been eradicated in the lower reaches of Menambery, Fanambana and Ampanobe the native species. Significant problems caused the destruction of the rainforest, due to the associated disturbance of the water balance lead many tributaries of the Menambery not more water throughout the year and thus fall out as suitable habitat. The water catchment area of the Fanambana is not affected to the same extent of deforestation, which is why the loss of habitat is here less pronounced. The water supply of the Ampanobe is stable due to less seasonal fluctuations in rainfall and a relatively intact forest cover. An introduced Gambusenart, Gambusia holbrooki, in its middle and upper reaches, however, is cause for concern because it carries a high grazing pressure on fish fry. The IUCN leads P. varatraza as endangered ( " endangered ").