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

Abstract

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.

Observations on Metal Concentrations in Tilapia (Oreochromis mossambicus) in Reservoirs of South Sri Lanka

“…Ch, chena (shifting cultivation land); Fc, forest cover; Gl, grassland; Hg, home gardens; Pl, paddy land; Pn, plantations (coconut, rubber, and tea); R, rock; Sl, shrub land; Wb, water bodies. (data used with permission from De Silva et al (2001). Use of geographical information systems as a tool for predicting "sh yield in tropical reservoirs: case study of Sri Lankan reservoirs.…”

“…The present study included reservoirs of a diverse nature, with respect to age of impoundment, size capacity, surface area, etc., from catchments with varying land-use patterns (Table 4). For the three catchments for which data have been collected, the major land types were shrub land, forest cover, shifting cultivation (slash-and-burn shifting cultivation, known locally as chena), and homesteads, with signi"-cant di!erences in predominant land use between reservoirs; e.g., Badagiriya is predominantly shrub land and forest, while Chandrikewewa in predominantly chena and homesteads (De Silva et al, 2001). Although Bodaly et al (1993) suggest that for temperate lakes remote from direct anthropogenic in#uences, mercury concentrations in "sh are related to lake temperature, not catchment characteristics, our GIS and PCA hint at a correlation between land-use patterns and "sh metal concentrations in these anthropogenically impacted, tropical lakes.…”

Food potential of continental aquatic ecosystems in China

“…It can be foreseen that the assessment of fishery productivity based on GIS should be a new hotspot in future fishery researches [17,18] .…”

Advance application of geospatial technology for fisheries perspective in Tarai region of Himalayan state of Uttarakhand

“…De Silva et al (2001) used GIS to integrate fishery yield data, fishing intensity, and landing size together with selected limnological data, such as conductivity and chlorophyll for nine tropical reservoirs in Sri Lanka. They established relations of fish yield to environmental parameters.…”