Science
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/1
Browse
2 results
Search Results
Item Feeding Ecology and Length-weight Relationship of Indian Glass Barb, Laubuka laubuca (Hamilton 1822) at Maguru Oya Stream (Deduru Oya River Tributary), Sri Lanka.(Asian Fisheries Society, 2016) Epa, U.P.K.; Narayana, N.M.A.J.Laubuka laubuca (Hamilton 1822) is a poorly studied freshwater fish found in South and Southeast Asia. This study was conducted to investigate the feeding habit and length-weight relationship of L. laubuca at Maguru Oya Stream, Sri Lanka. Gut contents of 180 fish were analysed, and food particles identified were categorised into 15 broad taxonomic groups. Relative abundance of each food category was calculated for 1-3, 3-5 and >5 cm length classes. Trophic niche breadth, food electivity index and Fulton’s condition factor of L. laubuca were calculated. Length-weight relationship was determined using the expression, W = aLb. Laubuka laubuca was a euryphagous-planktivorous fish and it showed a size dependent feeding pattern. Young fish had significantly broader (P<0.05) trophic niche breadth than that of adults. According to food electivity indices L. laubuca preferred euglenoids, rotifers, insect larvae, crustacean larvae, arachnid larvae and macrozoobenthos which were highly abundant in stream habitat. Laubuka laubuca showed a positive allometric growth pattern with length-weight relationship of log W = -2.3684 + 3.3528 log TL. Due to high availability of preferred food items in its habitat and positive allometiric growth L. laubuca could be categorised under least concern category in the IUCN Red List.Item Comparative feeding ecology of two fish species bluestripe herring, Herklotsichthys quadrimaculatus Ruppel (Clupeidae) and big eye scad, Selar crumenophthalmus Bloch (Clupeidae) caught in the stilt fishery in southern Sri Lanka(2016) Zoysa, M.C.L.; Epa, U.P.K.The dietary habits and food resources partitioning of H. quadrimaculatus and S. crumenophthalmus caught by stilt fishing in southern Sri Lanka were studied. Food particles found in the gut contents of 112 specimens of H. quadrimaculatus and 166 specimens of S. crumenophthalmus were identified. Different food categories were sorted by taxonomic groups to calculate food electivity, overlap, trophic niche breadth and food preference of each fish species. H. quadrimaculatus fed on both phytoplankton and zooplankton while S. crumenophthalmus solely fed on zooplankton. Gut content of H. quadrimaculatus consisted of 46 food items and it preferred diatoms, dinoflagellates and calanoid copepods. S. crumenophthalmus preferred calanoid copepods, cyclopoid copepods and crustacean larvae (protozoea and nauplii) and it consumed 41 food items. Two fish species had low dietary overlap (16%) and their niche breadth was significantly different (p< 0.05). Therefore, these two fish species can aggregate with minimum competition for food and that may be one of the reasons for their seasonal congregation on shallow reef areas in the Southern coast of Sri Lanka.