Broad Niche Overlap between Invasive Nile Tilapia Oreochromis niloticus and Indigenous Congenerics in Southern Africa: Should We be Concerned?

Entropy

Tsungai A. Zengeya²  Anthony J. Booth³  Christian T. Chimimba¹ 

[1] DST-NRF Centre of Excellence for Invasion Biology (CIB), Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa; E-Mail:;South African National Biodiversity Institute, Pretoria National Botanical Gardens, 2 Cussonia Avenue, Brummeria, Private Bag x101, Pretoria, 0184, South Africa;Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa; E-Mail:

关键词: ecological niche modelling;    invasion;    indigenous fishes;    Nile tilapia;    conservation;    southern Africa;   

DOI  :  10.3390/e17074959

来源: mdpi

【 摘 要 】

This study developed niche models for the native ranges of Oreochromis andersonii, O. mortimeri, and O. mossambicus, and assessed how much of their range is climatically suitable for the establishment of O. niloticus, and then reviewed the conservation implications for indigenous congenerics as a result of overlap with O. niloticus based on documented congeneric interactions. The predicted potential geographical range of O. niloticus reveals a broad climatic suitability over most of southern Africa and overlaps with all the endemic congenerics. This is of major conservation concern because six of the eight river systems predicted to be suitable for O. niloticus have already been invaded and now support established populations. Oreochromis niloticus has been implicated in reducing the abundance of indigenous species through competitive exclusion and hybridisation. Despite these well-documented adverse ecological effects, O. niloticus remains one of the most widely cultured and propagated fish species in aquaculture and stock enhancements in the southern Africa sub-region. Aquaculture is perceived as a means of protein security, poverty alleviation, and economic development and, as such, any future decisions on its introduction will be based on the trade-off between socio-economic benefits and potential adverse ecological effects.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland