Use of geographical information systems as a tool for predicting fish yield in tropical reservoirs: case study on Sri Lankan reservoirs

Use of geographical information systems (GIS) in inland fisheries has hitherto been essentially restricted to site evaluation for aquaculture development and assessment of limnological changes in time and space in individual water bodies. The present GIS study was conducted on the land-use pattern of the catchments of nine reservoirs in Sri Lanka, for which detailed fishery data, viz. yield, fishing intensity, landing size of major constituent species, together with selected limnological data such as conductivity and chlorophyll- a , were available. Potential statistical relationships (linear, curvilinear, exponential and second-order polynomial) of fish yield ( FY , in kg ha⁻¹ yr⁻¹) to different land-use patterns, such as forest cover ( FC , in km²) and shrub-land ( SL , in km²), either singly, or in combination, and/or the ratio of each land type to reservoir area ( RA in km²) and reservoir capacity ( RC in km³), were explored. Highly significant relationships were evident between FY to the ratio of SL and/or FC + SL to RA and/or RC . Similarly, the above land-use types to RA and RC ratios were significantly related to limnological features of the reservoirs. The relationships of FY to various parameters obtained in this study were much better correlated than those relationships of FY to limnological and biological parameters used in yield prediction in tropical and temperate lacustrine waters previously.     

无细胞分裂素培养基上高效的大豆下胚轴外植体器官再生

虽然已经有大豆下胚轴再生植株的很多报道，但再生率总是很低并且不定芽的再生都是在添加细胞分裂素的培养基上取得的。这种培养基使外植体形成大量愈伤组织且阻碍了再生芽的进一步生长。为此本实验将表面灭菌的成熟种子置2种培养基上萌发，一种添加2 mg/L苄基腺嘌呤（BA）而另一种不添加；6 d后将小苗的下胚轴切下作为外植体培养到两种诱导不定芽再生的培养基上，同样一种添加2 mg/L BA而另一种不添加。在9个当地、2个美国和1个巴西共12个供试品系中，最好的培养结果是在含2 mg/L BA的培养基上萌发、长 苗、切取下胚轴并在不含BA的再生培养基诱导不定芽。以此程序，不定芽的再生率和质量都得到了显著提高，其中一个当地品种“广大粒”的再生率达到了72%。     

Distribution,habitat associations and conservation implications of Sri Lankan freshwater terrapins outside the protected area network

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Sri Lankan reservoir fishery: a case for introduction of a co-management strategy

The inland fisheries of Sri Lanka are essentially artisanal on most of the reservoirs in the country. The annual inland fish production declined dramatically after 1990, when state patronage for the development of the inland fisheries was discontinued for 4 years. This decline was shown to be a result of growth overfishing of the two dominant cichlid species which accounted for over 90% of landings. This was a result of using small mesh ( < 6.9 cm) gillnets in the absence of the State-sponsored monitoring procedure in the fishery after 1990. This indicates that it is necessary to monitor inland fisheries management in Sri Lanka through a centralized authority in the current situation. However, in some Sri Lankan reservoirs, fishing communities can be categorized as 'organized' because they collectively make decisions to define procedures for the rational exploitation of the fishery resources. In reservoirs with 'organized' fishing, the communities themselves have developed mechanisms to regulate the landing sizes of dominant cichlid fish species through community-based fisheries management strategies. In such reservoirs, over-exploitation of fish stocks was not evident, even after 1990, when state-sponsored monitoring procedures were suspended. Based on these observations, an alternative approach is recommended for the management of Sri Lankan reservoir capture fisheries in which the Government and resource-users have equal responsibilities in the management of the resources.     

Traditional ‘maavee’ rice production in Sri Lanka: environmental,economic and social pressures revealed through stakeholder interviews

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An evaluation of the role and impacts of alien finfish in Asian inland aquaculture

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ABSTRACT

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