Browsing by Author "Athukorala, D.A."

Filter results by typing the first few letters
Now showing 1 - 5 of 5
  • No Thumbnail Available
    Item
    Emerging boost in Sri Lankan reservoir fish production: a case of adoption of past research findings
    (Network of Aquaculture Centers in Asia-Pacific, 2009) Amarasinghe, U.S.; Weerakoon, D.E.M.; Athukorala, D.A.
  • No Thumbnail Available
    Item
    Emerging boost in Sri Lankan reservoir fish production: a case of adoption of past research findings
    (Journal of Yojana, 2002) Amarasinghe, U.S.; Weerakoon, D.E.M.; Athukorala, D.A.
  • No Thumbnail Available
    Item
  • No Thumbnail Available
    Item
    Gillnetting for small indigenous cyprinids in a Sri Lankan reservoir where culture-based fisheries are practiced
    (Sri Lanka Journal of Aquatic Sciences, 2020) Athukorala, D.A.; Amarasinbghe, U.S.
    In Sri Lankan reservoirs, small, indigenous fish species (SIS) are abundant and can be differentially exploited using small mesh (15-38 mm stretched mesh sizes) gillnets without any detrimental effects on the cichlid fisheries. However, in the recent past a paradigm shift in the reservoir fisheries of Sri Lanka is observed from total dependence on exotic cichlids to exploitation of exotic carps, stocked in reservoirs for the development of culture-based fisheries (CBF). As fingerlings of Chinese and Indian major carps and common carp are regularly stocked in reservoirs for the development of CBF, it is essential to investigate the potential impact of the use of small mesh gillnets to catch SIS on stocked fish fingerlings on CBF. In the present study, small mesh gillnets were used to exploit SIS during September 2011 to March 2013 when carp fingerlings were stocked in Chandrika wewa, Sri Lanka. The results revealed that no carp fingerlings (except 2 specimens of Indian carp species) were caught in any of the fishing trials with small mesh gillnets. As juvenile fish and stocked fish fingerlings occur in shallow littoral areas of reservoir, and as small mesh gillnets are laid at the depths ≥ 1.5 m, there is a habitat segregation of these two categories of fish. It is therefore possible to introduce a subsidiary fishery with small mesh gillnets to exploit SIS, which can co-exist with CBF in reservoirs of Sri Lanka.
  • No Thumbnail Available
    Item
    Population dynamics of commercially important fish species in two reservoirs of the Walawe river basin, Sri Lanka
    (Asian Fisheries Society, 2010) Athukorala, D.A.; Amarasingha, U.S.
    Population dynamics of dominant fish species in two lowland reservoirs of Sri Lanka were studied based on length-based stock assessment methodologies, as implemented in FiSAT II software. The estimated growth parameters of Oreochromis mossambicus in Udawalawe and Chandrikawewa reservoirs and those of O. niloticus and Labeo dussumieri in Udawalawe reservoir fall within the growth space of auximetric plots of cichlids and cyprinids indicating reliability of estimates. In the Chandrikawewa reservoir where O. mossambicus exhibited faster growth, increased fishing pressure might lead to push the population towards the extreme of ‘rselected’ life strategy so that continuation of the fishery at the present exploitation level is advisable. Relative yield-per-recruit (Y’/R) analyses indicate that for O. niloticus and L. dussumieri in Udawalawe reservoir, exploitation levels can be increased to optimize Y’/R. However, since these two species and O. mossambicus are caught in the same fishing gear, exploitation rate for O. niloticus and L. dussumieri has to be increased to a level that would not lead to over-exploitation of O. mossambicus stock.