Conservation of endemic rain forest fishes of Sri Lanka : results of a translocation experiment

Four potentially endangered species of rain forest fishes, Barbus cumingi, Barbus nigrofasciatus, Barbus titteya, and Rasbora vateraoris, endemic to streams of southwestern Sri Lanka, were translocated in 1981 into a depauperate stream system in the central hills. By 1985 all four species had established self-perpetuating populations in these streams, and had extended their ranges into adjacent stream Barbus nigrofasciatus, a generalist, was one of the most abundant species in these stream It was widely dis- tributed throughout the stream system and in the slower sections of the Mabaveli Ganga (=Mabaveli River), and oc- cupied a wide range of macro- and microhabitat types. The other three species were more specialized in their habitat and diet, and were thus patchily distributed. The microhabitats occupied by B. cumingi, B. titteya, and R. vateritloris resem- bled the specialized microhabitats they occupy in their na- tive stream Presumably because of their specializations, these three species were not as abundant as B. nigrofasciatus. Overall, the biology and distribution of the four species will enable them to survive spatially small-scale environmental perturbations The results suggest that translocations are a feasible means of conserving other endemic fishes of Sri Lanka theatened with extinction. However, such transloca- tions must be carefully planne4 with consideration for the indigenous community as well as the ecological require- ments and genetic integrity of the target species. Resumen Cuutro especies de peces, potencialmente en pe- ligro de extinci6n de zonas de selvapluvial, Barbus cumingi, Barbus nigrofasciatus, Barbus titteya y Rasbora vaterifloris, que son endemicas a 10s rios del sudoeste de Sri Lanka, fumn reubicadas, en 1981, a un sistema empobrecido y deterio- rado de n'os, en las colinas centrales de esepais. En 1985 las cuatro especies habian establecido poblaciones auto- petpetuuntes en estos n'os, y habian expandido su rango a n'os adyacentes. Barbus nigrofasciatus, un generalist4 era unu de las especies truiS abundantes en estos ri'os Esta espe- cie se distribuio extensamente por todo el sistema de n,os y en las secciones truiS lentas del Mabaveli Ganga (el do Ma- haveli), y ocupo un amplio rango de tipos de macro- y mi- cro-habitats. Las otras tres especies son mciS especializadas en su habitat y dieta, y, por ello, se distn'buymn en foma irregulat: Los microhabitats ocupadospor B. cumingi, B. tit- teya, y R. vateriiloris se parecian a 10s microhabitats espe- cializados que ocupaban en sus ri'os nutivos. Sepresume de quepor su especialiazacioq estas tres especies no eran tan abundantes como B. nigrofasciatus. En general, la biologia y distribucion de las cuatro especies posibilitara su sobre- vivencia a perturbaciones ambientales de pequetia escala en lo espaciai Los resultados sugieren que la reubicacion es unu forma viablepara conservar a otrospeces endhicm de Sri Lanka amenazados de extinci6n. Sin embargo, las reubi- caciones deben ser cuidadmarnente planificados tanto en consideracion a la comunidad autoctoria, como, a las necesidades ecologicos y la integridad genetica de las espe- cies en consideraci6n.