Sri Lanka Journal of Aquatic Sciences最新文献_第9页

Multi-mesh gillnet selectivity of Oreochromis mossambicus and O. niloticus (Cichlidae) in the fishery of three large perennial reservoirs in Sri Lanka 斯里兰卡3个大型多年生水库渔业中，莫sambicis和niloticus的多目刺网选择性

Sri Lanka Journal of Aquatic Sciences Pub Date : 2017-03-01 DOI: 10.4038/SLJAS.V22I1.7517

R. Jayasinghe, Upali Sarath Amarasinghe, J. Moreau

{"title":"Multi-mesh gillnet selectivity of Oreochromis mossambicus and O. niloticus (Cichlidae) in the fishery of three large perennial reservoirs in Sri Lanka","authors":"R. Jayasinghe, Upali Sarath Amarasinghe, J. Moreau","doi":"10.4038/SLJAS.V22I1.7517","DOIUrl":"https://doi.org/10.4038/SLJAS.V22I1.7517","url":null,"abstract":"As in many tropical reservoir fisheries, the major fishing gear in the reservoirs of Sri Lanka is gillnet. Gillnets of a wide range of stretched mesh sizes (6.9 - 11.4 cm) are used in individual boats in Sri Lankan reservoirs targeting mainly two exotic cichlid species, Oreochromis mossambicus and O. niloticus , which dominate the fisheries accounting for over 80% of the landings. Although the filament characteristics and dimensions of gillnets of different mesh sizes are uniform, their mesh composition varies from boat to boat making catch samples in individual boats are under the influence of different selectivity patterns. As such, an approach is presented for constructing the overall selection curves in the sampled boats during different sampling occasions for the two cichlid fish species in the three reservoirs. For this purpose, gillnet selectivity of each mesh size was determined using Baranov-Holt method. Probabilities of capture of mesh-wise gillnet selection curves were then summed up giving weight to the contribution of each mesh size to the total number of net pieces in the sampled boat, to determine the overall gillnet selection from gillnets of all mesh sizes. The importance of the findings of the present study for length-based stock assessment methods and for imposing mesh regulations to the gillnet fisheries in reservoirs of Sri Lanka is discussed.","PeriodicalId":21784,"journal":{"name":"Sri Lanka Journal of Aquatic Sciences","volume":"1 1","pages":"141"},"PeriodicalIF":0.0,"publicationDate":"2017-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86922133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Assessment of water quality and trophic state in Sooriyawewa reservoir in the Southern province of Sri Lanka 斯里兰卡南部省Sooriyawewa水库水质及营养状况评价

Sri Lanka Journal of Aquatic Sciences Pub Date : 2017-03-01 DOI: 10.4038/SLJAS.V22I1.7512

L. Wijewardene, H. Asanthi, S. Rajapaksha

{"title":"Assessment of water quality and trophic state in Sooriyawewa reservoir in the Southern province of Sri Lanka","authors":"L. Wijewardene, H. Asanthi, S. Rajapaksha","doi":"10.4038/SLJAS.V22I1.7512","DOIUrl":"https://doi.org/10.4038/SLJAS.V22I1.7512","url":null,"abstract":"Trophic state of a reservoir is one of the important factors in limnological perspective in order to understand its healthiness. This study was focused to understand the dynamics of trophic state and water quality in Sooriyawewa reservoir in the Southern province of Sri Lanka. Water quality was evaluated in six sampling sites from August 2014 to March 2015 using standard methods. Significant temporal variation (p -1 ), NO 3 - (2.77±1.4 mg L -1 ), PO 4 3- (0.21±0.1 mg L -1 ), total suspended solids (15.24±10 mgL -1 ), conductivity (253.75±86.2 µScm -1 ) and temperature (29.90±0.5°C). PO 4 3- , NO 3 - and chlorophyll-a concentrations showed their highest levels in September, October and November respectively. Water Quality Index (WQI) values ranged from 11.62 (December) to 22.78 (November, January, February, March) indicating very poor water quality. The Trophic State Index (TSI) changed from slightly eutrophic to hyper-eutrophic status in October and November respectively coinciding higher chlorophyll-a concentration. Results showed that Sooriyawewa reservoir is not suitable to be used as a drinking water source under conventional treatment and continuous monitoring of water quality parameters should be carried out.","PeriodicalId":21784,"journal":{"name":"Sri Lanka Journal of Aquatic Sciences","volume":"4 1","pages":"9"},"PeriodicalIF":0.0,"publicationDate":"2017-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89311956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Survival and cholinesterase activity of Asian common toad (Duttaphrynus melanostictus) tadpoles following short term exposure to a carbosulfan-based pesticide 短期暴露于一种以碳硫胺为基础的杀虫剂后亚洲蟾蜍(Duttaphrynus melanotictus)蝌蚪的存活率和胆碱酯酶活性

Sri Lanka Journal of Aquatic Sciences Pub Date : 2017-03-01 DOI: 10.4038/SLJAS.V22I1.7514

H. Samarakoon, A. Pathiratne

{"title":"Survival and cholinesterase activity of Asian common toad (Duttaphrynus melanostictus) tadpoles following short term exposure to a carbosulfan-based pesticide","authors":"H. Samarakoon, A. Pathiratne","doi":"10.4038/SLJAS.V22I1.7514","DOIUrl":"https://doi.org/10.4038/SLJAS.V22I1.7514","url":null,"abstract":"Carbosulfan, a carbamate pesticide widely used in agriculture especially in the Asian region has received less attention in ecological impact assessments particularly to non-target amphibians. In this study, short term effects of a carbosulfan-based pesticide (Marshal ® ) on survival and cholinesterase (ChE) activity of tadpoles of Duttaphrynus melanostictus , a non-target amphibian in tropical Asia were evaluated. Based on the concentration-toxicity response patterns, estimated median lethal concentration (LC 50 ) and median ChE inhibitory concentration (IC 50 ) for 96 h were 24 and 2.1 mg/L carbosulfan respectively. For the ChE inhibition for 96 h, the lowest observable effect concentration and no observable effect concentrations of carbosulfan were 0.6 and 0.3 mg/L respectively. Upon transfer to pesticide-free water by 14 days, ChE activities of the tadpoles were restored to normal levels. Since the tadpoles exposed to 0.3 mg/L carbosulfan have not exhibited lethality, morphological deformities, abnormal behavior or statistically significant ChE depression, it is unlikely that the carbosulfan-based pesticide could induce neurotoxic effects for D. melanostictus tadpoles at the concentration of ≤ 0.3 mg/L of active ingredient under short term exposure.","PeriodicalId":21784,"journal":{"name":"Sri Lanka Journal of Aquatic Sciences","volume":"65 1","pages":"29"},"PeriodicalIF":0.0,"publicationDate":"2017-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88104559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

First record of plerocercoid larvae belong to the order Trypanorhyncha (Diesing 1863) isolated from swordfish (Xiphias gladius, Linnaeus 1758) captured off Sri Lanka 从斯里兰卡捕获的剑鱼(Xiphias gladius, Linnaeus 1758)中分离到的首个记录为锥虫目(Trypanorhyncha)

Sri Lanka Journal of Aquatic Sciences Pub Date : 2017-03-01 DOI: 10.4038/SLJAS.V22I1.7518

D. Silva, H. Fernando, R. Ranatunga, B. Silva

{"title":"First record of plerocercoid larvae belong to the order Trypanorhyncha (Diesing 1863) isolated from swordfish (Xiphias gladius, Linnaeus 1758) captured off Sri Lanka","authors":"D. Silva, H. Fernando, R. Ranatunga, B. Silva","doi":"10.4038/SLJAS.V22I1.7518","DOIUrl":"https://doi.org/10.4038/SLJAS.V22I1.7518","url":null,"abstract":"Parasitism leads to severe economic losses to marine fish exports in Sri Lanka. Swordfish is a seasonal species with high demand both locally and internationally. Presence of a parasite in their flesh confuses the suppliers with zoonotic Anisarkis spp. This study is aimed to identify the plerecercoid parasitic larvae found in swordfish and establish a feasible method of diagnosis at fish processing factories. Parasites buried in frozen swordfish ( Xiphias gladius ) muscles were isolated and stored in cold sea water. Samples were washed with normal saline water and observed under bright field light microscope at 40x and 100x magnifications, and the parasites were identified based on their morphological features. For further confirmation, confocalmicroscope was used to record scolex parameters. Total length of the parasites was 1.7 cm– 3.5 cm (2.27 cm). Presence of the elongated, acraspidote scolex (length 6.23 mm, width at pars bothridialis 2.4 mm) with four tentacular armature and curved, apically inverted, thick edged bothridia confirmed the parasitic larvae belonged to the Order Trypanorhyncha. Corona of falciform hooks in the basal armature and the heteromorphous hooks in a half spiral arrangement at metabasal armature are characteristics of the genus Molicola . This is the first record of the Trypanorhynch plerocercoid larvae (genus: Molicola ) isolated in swordfishes from Sri Lanka. This study emphasizes that morphological examination of the parasite scolex using bright field microscopy will be helpful to distinguish the parasitic genera and feasible to use in the fish processing factories.","PeriodicalId":21784,"journal":{"name":"Sri Lanka Journal of Aquatic Sciences","volume":"108 1","pages":"67"},"PeriodicalIF":0.0,"publicationDate":"2017-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81638888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Selection of the most suitable crustacean exoskeleton waste from fish processing industry to isolate chitosan 从鱼类加工业中选择最合适的甲壳类动物外骨骼废弃物分离壳聚糖

Sri Lanka Journal of Aquatic Sciences Pub Date : 2017-03-01 DOI: 10.4038/SLJAS.V22I1.7516

R. G. Sanuja, N. Kalutharage, P. Cumaranatunga

{"title":"Selection of the most suitable crustacean exoskeleton waste from fish processing industry to isolate chitosan","authors":"R. G. Sanuja, N. Kalutharage, P. Cumaranatunga","doi":"10.4038/SLJAS.V22I1.7516","DOIUrl":"https://doi.org/10.4038/SLJAS.V22I1.7516","url":null,"abstract":"Shell waste produced by the sea food industry is one of the most significant problems contributing for environmental and health hazards. The most frequent method employed for disposal of these waste is burning which is environmentally costly due to low burning capacity of shells. In such a scenario, conversion of shrimp shell waste to chitosan, a commercially valuable product with a myriad of uses, could serve as an effective mode of shell remediation. Chitosan was obtained from shellfish waste by deproteination, demineralization, discoloration and deacetylation processes. It was characterized using Fourier Transformed Infra-Red (FT-IR) spectroscopy. The physico-chemical parameters such as moisture content, ash content, solubility, N-content, water binding capacity (WBC), fat binding capacity (FBC) and degree of deacetylation (DD) were analysed to compare the extracted six chitosan samples from Penaeus monodon , Portunus pelagicus , Portunus sanguinolentus , Scylla serrata , Panulirus homarus and Panulirus versicolor. The ranges for percentage yield, moisture content, ash content, N-content, percentage solubility, and WBC were 14.53±0.47%-34.13±3.72%, 3.16±1.77%-7.52±1.11%, 0.65±0.23%-53.52±5.65%, 2.02±0.03% - 6.16±0.10%, 15.28±0.62% - 47.91±5.15%, and 262.94±20.88% - 600.61±58.11% respectively. FBC varied approximately from 250% to 650% in coconut oil, sunflower oil and soybean oil. Among the six chitosan samples, P. monodon was the most suitable crustacean exoskeleton waste from fish processing industry to isolate chitosan due to the fact that in the processing of shrimps for human consumption, 40 - 50 % of the total mass is discarded as waste and high quality of chitosan extracted. Therefore, there is a high possibility of extracting good quality chitosan using exoskeleton waste of Penaeus monodon .","PeriodicalId":21784,"journal":{"name":"Sri Lanka Journal of Aquatic Sciences","volume":"3 1","pages":"45"},"PeriodicalIF":0.0,"publicationDate":"2017-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88471180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Shedding of gill epithelia by grey mullets (Family Mugilidae) in Negombo Estuary, Sri Lanka 斯里兰卡尼甘布河口灰鲻鱼鳃上皮脱落

Sri Lanka Journal of Aquatic Sciences Pub Date : 2016-06-24 DOI: 10.4038/SLJAS.V21I2.7509

M. Gammanpila, M. Wijeyaratne, Upali Sarath Amarasinghe

引用次数: 1

Impaired growth and erythrocyte nuclear lesions of immature Oreochromis niloticus exposed to waterborne crude oil: Persistent responses 暴露于水性原油的未成熟尼罗鱼的生长受损和红细胞核损伤:持续性反应

Sri Lanka Journal of Aquatic Sciences Pub Date : 2016-06-24 DOI: 10.4038/SLJAS.V21I2.7507

S. Gunawickrama, P. Panawala, K. Gunawickrama

引用次数: 0

Community based fish nurseries at Kirawana and Rajawewa in the Ampara district, Sri Lanka: A success story 斯里兰卡安帕拉地区基拉瓦纳和拉贾韦瓦的社区养鱼场:一个成功的故事

Sri Lanka Journal of Aquatic Sciences Pub Date : 2016-06-24 DOI: 10.4038/sljas.v21i2.7510

W. Fernando, K. Pushpalatha, J. Chandrasoma

{"title":"Community based fish nurseries at Kirawana and Rajawewa in the Ampara district, Sri Lanka: A success story","authors":"W. Fernando, K. Pushpalatha, J. Chandrasoma","doi":"10.4038/sljas.v21i2.7510","DOIUrl":"https://doi.org/10.4038/sljas.v21i2.7510","url":null,"abstract":"Under the Aquatic Resource Development and Quality Improvement project (ARDQIP) of the Ministry of Fisheries and Aquatic Resources Development of Sri Lanka, 25 community-based mini-nurseries involving community groups were established in 10 districts of Sri Lanka. Of these, two were established at Kirawana and Rajawewa in the Ampara district in 2006. Each fish nursery established on lands with an extent of 0.8 ha, consisted of 10 mud ponds with water area of around 4,500 m 2 . Fish fry of Nile tilapia, catla, rohu, mrigal and common carp were reared upto fingerling stage in these mini-nurseries. In general, 3 culture cycles (range from 45-70 days) have been carried-out per annum. Average number of fish fingerlings produced per culture cycle during 2013-2014 were 242,301 (Kirawana) and 262,935 (Rajawewa). Average survival rates from fry to fingerling stage achieved in Kirawana and Rajawewa mini-nurseries were 71.8% and 79.2% respectively. Production cost per fingerling was Rs. 0.69 and Rs. 0.76 respectively for Kirawana and Rajawewa. Net profit obtained per annum was Rs. 953,085.00 in Kirawana and Rs. 974,643.00 in Rajawewa [In May 2016, 1 USD ≈ Rs. 146.9]. Net profits earned by operating mini-nurseries were seven times higher, when compared with the profits generated through paddy cultivation on a land of similar extent. During 2009-2014 period, these mini-nurseries collectively made a contribution of 20.3% to the total fish fingerlings stocked in the Ampara district. Rearing of fish fry to fingerling stage is a very profitable enterprise for rural communities and well-managed fish nurseries can play an important role in meeting the fingerling requirement to develop culture-based fisheries in inland reservoirs of the country.","PeriodicalId":21784,"journal":{"name":"Sri Lanka Journal of Aquatic Sciences","volume":"14 1","pages":"157"},"PeriodicalIF":0.0,"publicationDate":"2016-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85133704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Water quality of Nilwala River, Sri Lanka in relation to land use practices 斯里兰卡尼尔瓦拉河水质与土地利用的关系

Sri Lanka Journal of Aquatic Sciences Pub Date : 2016-06-24 DOI: 10.4038/SLJAS.V21I2.7504

J. Jayawardana, T. Jayathunga, E. Edirisinghe

{"title":"Water quality of Nilwala River, Sri Lanka in relation to land use practices","authors":"J. Jayawardana, T. Jayathunga, E. Edirisinghe","doi":"10.4038/SLJAS.V21I2.7504","DOIUrl":"https://doi.org/10.4038/SLJAS.V21I2.7504","url":null,"abstract":"The Nilwala River is the third largest in the southern province of Sri Lanka which runs through 72 km along its cause. Conversion of forest lands to agricultural lands, expansion of urban areas and clearing of land for construction purposes in the catchment are major issues affecting water quality in Nilwala River. The water quality of the Nilwala River lower basin at 16 locations was estimated for 4 months from September2010 to December 2010 in two-week intervals. Water quality parameters pH, Electrical conductivity(EC), Dissolved oxygen (DO), Biochemical Oxygen demand (BOD 5 ), turbidity, colour, Total Dissolved Solids (TDS), total hardness, alkalinity, Nitrite-N (NO 2 - -N), Nitrate -N (NO 3 - -N), Phosphate (PO 4 3- -P), Sulphate (SO 4 3- ), Total Fe, Ca 2+ , F - and Cl - were evaluated in the sampling locations. The spatial and temporal variation of water quality associated with different land use categories were analyzed using Two-way ANOVA. Principal Component Analysis (PCA) and Cluster Analysis (CA) were also conducted to determine the association between water quality variation and land use impacts of the catchment. A significant (p +2 among sites were observed to be associated with different land use categories. No significant (p >0.05) temporal variability in water quality parameters except Nitrite and hardness was detected. PCA and CA also indicated a strong association between the water quality variables and the land use types of the river basin. Urban impacts, land clearance in the catchment and sand mining activities of the river bed were found to be the most significant impacts to the water quality of the river and areas with forest cover having positive impact to the water quality. These findings emphasize the need of better catchment management approaches and remediation of urban impacts on river water quality.","PeriodicalId":21784,"journal":{"name":"Sri Lanka Journal of Aquatic Sciences","volume":"3 1","pages":"77"},"PeriodicalIF":0.0,"publicationDate":"2016-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90080815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Capturing local knowledge of beach seine fishers in the north-western province of Sri Lanka 捕捉斯里兰卡西北省海滩围网渔民的当地知识

Sri Lanka Journal of Aquatic Sciences Pub Date : 2016-06-24 DOI: 10.4038/SLJAS.V21I2.7508

N. D. Gunawardena, Upali Sarath Amarasinghe

{"title":"Capturing local knowledge of beach seine fishers in the north-western province of Sri Lanka","authors":"N. D. Gunawardena, Upali Sarath Amarasinghe","doi":"10.4038/SLJAS.V21I2.7508","DOIUrl":"https://doi.org/10.4038/SLJAS.V21I2.7508","url":null,"abstract":"Local knowledge of fishers is considered to be useful in establishing effective dialogue between fishers and fishery managers to foster the sharing of power and responsibility between the government and local resource users. However, fishers’ local knowledge is often considered anecdotal and consequently, these knowledge bases are largely underutilized for small-scale fisheries management. This study was an attempt to investigate whether local knowledge of beach seine fishers of the north western province of Sri Lanka could be used to assist in optimizing their harvests, to scientifically validate anecdotal local knowledge and to recognize this knowledge base as an important means for defining fisheries co-management strategies. The beach seine fishers in nine fishing communities use their local knowledge to predict the occurrence of fish schools based on some indicators such as sea surface colour due to the presence of fish schools, turbulence of surface water in the presence of schools of larger fish species and behaviour of sea birds. Fishers were also aware that local weather conditions influence the occurrence of certain fish species. Accordingly, fishers select the appropriate cod end type to catch predicted species. Spatial and temporal variations of species composition were found to be in accordance with the fishers’ local knowledge. Level of accuracy of fishers in all nine beach-seine fisher communities under the present study in selecting the appropriate cod end to be fixed to catch target species was high (64.9% - 82.9%). Psychometric approach adopted has shown that the mean harvest and mean daily income of fishing communities had significant positive correlations with fishers’ knowledge about management-related aspects. Results of this study have shown that fishers’ local knowledge is reasonably consistent and should therefore be incorporated for defining effective fisheries co-management.","PeriodicalId":21784,"journal":{"name":"Sri Lanka Journal of Aquatic Sciences","volume":"30 1","pages":"125"},"PeriodicalIF":0.0,"publicationDate":"2016-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78891492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3