Exotic fish species in a global biodiversity hotspot: observations from River Chalakudy, part of Western Ghats, Kerala, India

• Published in: Biological invasions 2008-01, Vol.10 (1), p.37-40
• Main Authors: Raghavan, Rajeev, Prasad, Gopalan, Anvar-Ali, P. H, Pereira, Benno
• Format: Article
• Language: English
• Subjects: Altitude; Biodiversity; Biodiversity hot spots; Biomedical and Life Sciences; Conservation biology; Developmental Biology; Downstream; ecological invasion; Ecology; Fish; Freshwater; Freshwater & Marine Ecology; Gambusia affinis; Introduced species; Life Sciences; Nonnative species; Oreochromis mossambicus; Original Paper; Osphronemidae; Osphronemus; Osphronemus goramy; Plant Sciences; Poecilia reticulata; Rivers; Shoals; Xiphophorus; Xiphophorus maculatus
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-007-9104-2

We record here the occurrence of five exotic fish species viz Oreochromis mossambicus, Gambusia affinis, Osphronemus goramy, Xiphophorus maculatus and Poecilia reticulata in the Chalakudy River, part of the Western Ghats, a global biodiversity hotspot in Kerala, India. O. mossambicus was ubiquitous in occurrence with large shoals being encountered at all sampling sites spread along the downstream-upstream gradient of the river, including at an altitude of 1050 m ASL. Osphronemus goramy was recorded from the downstream region of the river while Gambusia affinis was recorded from three sampling sites located downstream as well as midstream. Xiphophorus maculatus was collected from a second order stream flowing through a tea plantation at an altitude of 1050 m ASL. Samples of brooders and early fry of Poecilia reticulata indicate that the fish has already established a breeding population in the river. Possible threats to the indigenous fish fauna of the Chalakudy River as a result of the invasion and proliferation of these exotics is discussed.