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Food‐web patterns and diversity in tropical fish communities
Author(s) -
Amarasinghe Upali S.,
Vijverberg Jacobus,
Weliange Wasantha S.,
Vos Matthijs
Publication year - 2014
Publication title -
lakes and reservoirs: research and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.296
H-Index - 39
eISSN - 1440-1770
pISSN - 1320-5331
DOI - 10.1111/lre.12056
Subject(s) - food web , trophic level , species richness , detritus , macrophyte , biology , ecology , abundance (ecology) , fishery
The food webs for three S ri L ankan reservoirs, M inneriya (ancient and shallow), U dawalawe (young and shallow) and V ictoria (young and deep), were compared. The species richness of the fish communities was highest in M inneriya (30 species), intermediate in U dawalawe (21 species) and lowest in V ictoria (18 species). The fish species belonged to 11 families, with C yprinidae dominating the community in terms of both abundance and species richness. The daily quantity of food consumed per fish species was used to distinguish weak from strong trophic interactions in these food webs. The fish community consumption pattern was characterized by a few strong interactions and many weak ones. The number of major consumers (i.e. contributing >5% of the total fish community consumption) for each reservoir was small and similar for all three reservoirs. D awkinsia singhala and A mblypharyngodon melettinus were the two major consumers in all three reservoir food webs. P untius chola was a major consumer in M inneriya and Victoria, although not in Udawalawe, where it fed less on detritus than for the other two food webs. The fish community fed mainly at the bottom of the food web, primarily on algae, macrophytes and detritus in all three reservoirs, with very little piscivory occurring. The average food‐web length was measured as the mean trophic index weighted for the consumption rates of the various fish populations that together comprised the fish community. The average food‐web length in these three S ri L ankan reservoirs relatively short, compared with most other tropical lake/reservoir food webs in A sia and A frica for which relevant data were available. Furthermore, traditionally unexploited species ( O reochromis mossambicu s; O . niloticus ), in contrast to species of commercial fisheries interest, are major role players in the trophic dynamics of reservoir ecosystems. Thus, based on this study, the potential of their exploitation should be considered in the management of reservoir fisheries.