Zoology
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Item Studies on the biology of young grey mullet, Mugil cephalus L.(FAO of United Nations, Rome, Italy, 1976) de Silva, S.S.; Wijeyaratne, M.J.S.Item Selectivity patterns in the multi-net gillnet fishery for Cichlid species in Sri Lankan reservoir(Department of Zoology, National University of Singapore, 1992) Amarasinghe, U.S.; de Silva, S.S.Item A rationale for introducing a subsidiary fishery in tropical reservoirs and lakes to augment inland fish production: case study from Sri Lanka(2016) Amarasinghe, U.S.; Kumara, P.D.A.; de Silva, S.S.An extra 30–40 million tonnes of food fish will be required by 2050 to meet the increasing need for a growing population. In the wake of plateauing of the traditional food fish supplies from marine capture fisheries, the gap in the supplies will have to be met from aquaculture and other plau- sible strategies, including increased inland fish production. The existing fisheries in tropical reservoirs and lakes tradition- ally tend to target only table-sized fish, often exotics and/or translocated species, using a single type of gear, mostly gill nets. In such fisheries, many small indigenous species (SIS) are unexploited due to the prohibition of the use of suitable fishing gear. The status of fisheries for small, indigenous species of four Sri Lankan reservoirs was investigated with a view to identifying regulatory con- straints to the establishment of SIS fisheries without adversely impacting existing commercial fisheries. It is estimated that a potential of 7.5 t per fisher per annum of SIS through the introduction of a new fishery is obtainable. This study is significant as SIS are recog- nized as important sources of essential macro- and micronutrients which can play a crucial role in combating malnutrition and micronutrient deficiencies in rural popula- tions of many South and Southeast Asian countries.Item Application of a Multiple-criteria decision making approach for selecting non-perennial reservoirs for culture-based fishery development: Case study from Sri Lanka(Elsevier, 2016) Wijenayake, W.M.H.K.; Amarasinghe, U.S.; de Silva, S.S.In Sri Lanka, small non-perennial reservoirs (mostly < 50 ha) are numerous in the dry zone receiving less than 185 cm annual precipitation. These are irrigational and are not traditionally used for inland fisheries, due to inadequate natural recruitment, but have the potential for utilization for the development of culture-based fisheries (CBFs), a form of extensive aquaculture. However, the suitability of water bodies for CBF is wide ranging because of the seasonal water retention period and fingerling availability for stocking, variable biological productivity, and community willingness to adopt CBF. In such circumstances multi-criteria decision making (MCDM) approaches are useful for selection of water bodies for CBF. Analytic hierarchy process (AHP), a MCDM approach was employed in this study where, three main criteria (reservoir productivity, catchment characteristics and socio-economic factors) that influence CBF yield were considered. There were two, five and three sub-criteria under each, respectively. As most of the sub-criteria in the analysis are essentially spatial data, it was possible to quantify the influence of each of these on CBF yield using geographical information systems (GIS) and remote sensing (RS) techniques, which were subsequently weighted. Based on the total scores from the weighted linear combinations of the AHP for various sub-categories, the reservoirs were categorized for their suitability for CBF in to four levels as excellent, good, fair and poor. As there was a positive significant relationship between the total AHP score and CBF yield, it was concluded that use of AHP based weighted linear combination would be a feasible approach for selection for CBF development, and that this methodology would be applicable to comparable situations in the tropical region.Item Extent of the catchment of reservoirs of Sri Lanka: an important aspect in the management of their capture fisheries(Asian Fisheries Forum, 1998) Nissanka, C.; Amarasinghe, U.S.; de Silva, S.S.Item An appeal to redefine stunning in Oreochromis mossambicus (Cichlidae)(Asian Fisheries Forum, 1998) Amarasinghe, U.S.; de Silva, S.S.Item Fishes and fisheries of Asian inland lacustrine waters(John Wiley & Sons, Ltd, Chichester, UK., 2015) Amarasinghe, U.S.; de Silva, S.S.In tropical Asia, there is a general paucity of natural lakes that are mainly located in the island states of the Philippines and Indonesia. Reservoir construction is extensive in the region primarily for irrigation, flood control and hydroelectricity generation, and fish production is essentially a secondary use of these reservoirs. Although the degree of endemism can in no way be equated to those in the great lakes of rift valley region of East Africa, familial diversity of fishes in Asia, but not species diversity, is considerably higher than in African lakes. Asia has a significant contribution to the world inland capture fisheries production of 11.5 × 106 t that is c. 69%. In most countries in Asia, the bulk of inland fisheries for food fish production occur in lacustrine waters, albeit productive riverine fisheries occur in the Lower Mekong Basin. Nevertheless, fisheries in multipurpose reservoirs are not fully appreciated compared to their other economic uses. Fisheries enhancement in lacustrine waterbodies in Asia through culture-based fisheries (CBF) is considered environmentally friendly due to low external inputs such as provision of supplementary feeds. There is a great potential for food fish production through CBF development in many parts of Asia. Hitherto, deterioration of water quality due to anthropogenic activities is less frequent in Asia than in other regions as local authorities are active in maintaining water quality in reservoirs used for multiple purposes. As reservoir water levels range from highly stable systems to highly fluctuating systems, a combination of flood pulses and mean depth can be used as a fish yield predictor in lakes and reservoirs. Approaches directed towards addressing both human and ecological well-being, in the lake and reservoir fisheries development strategies, are useful to combine the important aspects that are of ecological and societal interest. There is a paucity of studies on climate change impacts on inland fisheries, although some isolated studies are reported on specific aspects. Hence, there is a need to step up research on climate change impacts on inland fisheries for enabling adoption of mitigation and adaptive measuresItem Some Chemical Characteristics of Fresh and Salt-Dried Tilapia mossambica Peters(National Science Council of Sri Lanka, 1979) de Silva, S.S.; Rangoda, M.Item Studies on the fish ponds at Pitipana, Negombo 1. Seasonal and diurnal variation of some hydrobiological factors(The Fisheries Research Station, 1979) de Silva, S.S.; Silva, E.I.L.Item Fish Fauna of a coastal lagoon in Sri Lanka: Distribution and seasonal variation(The Fisheries Research Station, 1979) de Silva, S.S.; Silva, E.I.L.