Abstract
Oreochromis mossambicus (Peters, 1852) is a highly successful invader of aquatic ecosystems due to its adaptable life history, tropic flexibility, ability to tolerate extreme and often unfavourable environmental conditions, rapid reproduction and maternal care of offsprings. Upon introduction to areas outside its natural range, these characteristics ofte give O. mossambicus a competitive advantage over indigenous fishes. The present study investigated the population characteristics of non-indigenous Mossambique Tilapia, O. mossambicus, for a period of 12-months from August 2009 to July 2010 in the lower stretch of Yamuna River in India. The Mossambique Tilapia, O. mossambicus, formed the most abundant fish species in all the catches from the Yamuna River at all the sampling stations. The gonado-somatic index (GSI) and the presence of all six gonadal stages confirmed that O. mossambicus has established a breeding population. The GSI for females indicated year-round reproduction with increased spawning intensity in spring (March to April) and monsoon (July to August). Males ranged from 142-280.0 mm total length (TL) and females from 130-265.0 mm TL. Small juvenile fish were collected every month of the year and multiple size classes present in sampling catches suggest successful recruitment of young. Adult O. mossambicus consumed primarily detritus and vegetal matter, though the diet of juveniles, collected from the Yamuna River, was found to be carnivorous. We expected Mozambique tilapia to further invade the Yamuna River due to natural dispersal. There is a need for more detailed studies of tilapia abundance, recruitment and local environmental conditions across the country to fully understand the invasion potential and consequences for the endemic aquatic biodiversity. Key words: Exotic fish, Oreochromis mossambicus, invasion, colonization, Yamuna River, U.P.
Highlights
India is a vast country in terms of natural resources and considered one of the mega-biodiversity countries in the world (Lakra et al, 2011)
Over the last few decades riverine ecosystems of India has suffered from intense human intervention resulting in habitat loss and degradation and as a consequence, many fresh water fish species have become highly endangered, particular in Yamuna basin where heavy demand is placed on fresh waters
The characteristics that make O. mossambicus desirable as an aquaculture species predispose it for success as an invasive species (Canonico et al, 2005)
Summary
India is a vast country in terms of natural resources and considered one of the mega-biodiversity countries in the world (Lakra et al, 2011). The diverse river system in India harbour one of the richest fish germplasm resources in the world (Vass et al, 2009), characterized by many rare and endemic fish species. Ganie et al 311 and as much as 166 indigenous fish species have so far been recorded from the rivers of Central India (Sarkar and Lakra, 2007). A new and potentially serious threat to the indigenous fish faunais the invasion of alien fishes (Singh and Lakra, 2011). The negative effects of introduced species are widely recognized (Canonico et al, 2005; Lakra et al, 2008; Singh and Lakra 2006, 2011), many of them are still being released into the aquatic ecosystems of India for production enhancement, without consideration of their potential impact on native fish and fisheries
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
