Management implications of the response of two tilapiine cichlids to long-term Changes in Lake level, allodiversity and exploitation in an equatorial lake
Date
2011Author
Oyugi, Dalmas Oyugi
Harper, David Matthew
Ntiba, Japheth Michemi
Kisia, Seth Marande
Britton, John Robert
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
The tilapiine cichlids Oreochromis leucostictus and Tilapia zillii were introduced into Lake Naivasha, Kenya, in 1956. Previous studies on data collected to 1987 revealed they were persistent following establishment, despite environmental variability and exploitation. Recent data, however, suggest this persistence is under threat as data indicate some significant declines in aspects of their abundance since 1999. The influence of changes in lake level, allodiversity and fishing effort on this decline was tested and showed that a decline in lake level was a significant causal factor. The recent change in allodiversity, with the establishment and dominance of Cyprinus carpio in the fishery, was not significant on the catch per unit effort of O. leucostictus but was on T. zillii. Since 1999, catches of tilapiines in the fishery have been independent of fishing effort, contrary to between 1975 and 1987, suggesting their management through application of fishery models may no longer be applicable. As it was anthropogenic-mediated lake level changes that were mainly responsible for their decline, then lake management should focus on sustainable water utilization that maximizes lake levels in accordance with the basin-wide water balance
URI
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3357815/http://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/15836
Citation
Ambio. 2011 July; 40(5): 469–478.Publisher
School of Biological Sciences