Perennial Reservoirs Research Articles

Livelihood status of the fishing community of Mahakanadarawa reservoir in Anuradhapura, Sri Lanka

Mahakanadarawa reservoir located in Anuradhapura is one of the major, perennial reservoirs in Sri Lanka, extending over 1,457 ha. It provides livelihood opportunities through fisheries, irrigation for agriculture, and fostering economic growth in the surrounding region. Yet the fisheries-based livelihoods of the Mahakanadarawa reservoir have not been fully assessed. Hence, this study investigated the fishery and fisher profile of the reservoir. Primary data were collected from eight landing sites. A pre-tested questionnaire was used to interview 72 fishermen using a mixed method. Main variables including social, human, physical, natural, and financial capitals, fishery profile, fish and fisheries-based post-harvesting techniques, market chain analysis, and fisheries management practices, catch per unit effort for the gillnet fishery were calculated. Secondary data including stocking fish fingerlings and species-wise harvesting data for the past 10 years were collected from the district aquaculture extension office (Anuradhapura) of the NAQDA. A secondary study on the length-weight relationship of Oreochromis niloticus along with its condition factor value was performed. It was revealed that O. niloticus had negative allometric fish growth (b = 2.6667) with a condition factor value of 1.9092. The female fish had a higher mean total length compared to the male fish. In the fishing community, 95.83% of males and 4.17% of females were engaged in fishery activities. Mainly gill nets and non-mechanized fiberglass canoes were used for fishing. The average CPUE was 0.000339 kgm-2day-1. A strong positive (r =0.841) correlation was reported for fish stocking and fish production. Fish smoking and sun drying were the common fish processing techniques. The fish supply chain targeted the regional market. A cooperative level co-management system was identified among the reservoir fishing community. The current study discloses the livelihood capitals of the fishing community along with the existing supply chain which can be utilized for the sustainable management strategy of the Mahakanadarawa reservoir in the long run.

The trophic state of the reservoir influences the allometric coefficient and condition factor of Giant Freshwater Prawn (Macrobrachium rosenbergii) cultured in perennial reservoirs of Sri Lanka

Giant Freshwater Prawn (Macrobrachium rosenbergii) is an essential crustacean species in culture-based fisheries of Sri Lanka. Studying the morphometric characteristics and empirical models in fishing and aquaculture is highly beneficial; thus, it is the most accurate way of analyzing growth patterns. The present study aimed to establish the length-weight relationship and compute the relative condition factor for the M. rosenbergii cultured in trophically different perennial reservoirs in Sri Lanka, considering the trophic status of the reservoirs. The allometric coefficient and condition factor of M. rosenbergii concerning the trophic state of the reservoir were empirically ascertained from the samples collected from twenty-five dry-zone perennial reservoirs of Sri Lanka. Carlson's Trophic State Index (TSI) was calculated based on the chlorophyll-a content. The allometric coefficient and relative condition factor were computed using the total length and weight of the M. rosenbergii. The TSI ranging between 44.09±0.47 and 65.15±0.24 differed significantly (p<0.05). Sexual dimorphism in the growth of males over the female M. rosenbergii was ascertained with the aid of allometric coefficient (b value) 3.2306 (positive allometric growth) and 2.9534 (negative allometric growth), respectively. In eutrophic perennial reservoirs, Giant Freshwater Prawns showed the highest allometric coefficient in both sexes. There was a positive correlation between the allometric coefficient and TSI among males, r(23)=0.7210, p<0.001, and combined sexes, r(23)=0.7900, p<0.001, respectively. The results of the present study revealed that the trophic state of the reservoir influences the allometric coefficient and condition factor of M. rosenbergii cultured in perennial reservoirs of Sri Lanka.

Hydro-climatic consequences on zooplankton diversity and abundance in perennial Vavuniya reservoir and seasonal Thandikulam reservoir in Vavuniya, Sri Lanka

BackgroundZooplankton exhibit strong responses for minute changes in their habitat. Therefore, this study intended to investigate the impacts of hydro-climatic factors and related water quality variables on zooplankton abundance and diversity in the perennial Vavuniya reservoir (VR) and seasonal Thandikulam reservoir (TR), Vavuniya, Sri Lanka.ResultsZooplankton diversity and abundance showed some peculiarities between seasonal and perennial reservoirs under varying hydro-climatic factors and water quality parameters during wet and dry seasons (July 2018–February 2019). There were 14 Rotifera, 4 Cladocera and 5 Copepod species in VR, and in TR, 12 Rotifera, 2 Cladocera and 5 Copepod species were identified. Although these reservoirs are located at proximity (2.48 km), the responses via zooplankton community structure toward environmental factors have been shown uniqueness to some extent. Significant negative correlation was observed for increasing {text{NO}}_{{3}}^{ - } (p = 0.044) and {text{PO}}_{{4}}^{{{3} - }} (p = 0.010) concentrations with zooplankton diversity in perennial VR; however, only {text{PO}}_{{4}}^{{{3} - }} concentration showed a significantly (p = 0.042) negative correlation in seasonal TR. Interestingly, total zooplankton abundance showed significant negative correlations with {text{NO}}_{{3}}^{ - } (p = 0.013) and {text{PO}}_{{4}}^{3 - } (p = 0.038) in perennial VR; however, insignificant negative correlation was observed in seasonal TR. Copepods make up the majority of total zooplankton abundance in both reservoirs and were significantly affected by increased atmospheric temperature. Cladocera abundance in VR was highly sensitive (p = 0.032; r = − 0.856) to changes in water level. Increasing water level significantly favors the total zooplankton abundance in the seasonal reservoir but not in perennial.ConclusionsSensitivity of zooplankton community structure varies between seasonal and perennial reservoirs in different magnitudes. This is due to the increasing temperatures, increasing phosphate levels and decreasing water levels with the combination of other factors resulting in specific responses of zooplankton diversity and abundance. Therefore, it would not be surprised to use zooplankton community structure to sense the vibrant responses of different freshwater habitats.

The Impact of the Surrounding Land Uses on Water Quality of Some Selected Cascade and Perennial Tanks in Anuradhapura District, Sri Lanka

The present study was conducted to evaluate the water quality of the inlet, irrigation outlet, and edges linked to Nuwarawewa reservoir, Mahakanadarawa reservoir, Hurulu wewa reservoir, Sangilikandarawa reservoir, and Nachchaduwa perennial reservoir in Anuradhapura, Sri Lanka. Water samples were taken from a designated position of each inlet, irrigation output, and edges in the second inter-monsoon, northeast monsoon, and first inter-monsoon seasons. Water quality indicators such as pH, electrical conductivity (EC), total dissolved solids (TDS), Na, K, Ca, Mg, Sodium Adsorption Ratio (SAR), NO3- -N, NH4+-N, dissolved reactive phosphorus (DRP), and heavy metals (Cd, As, Pb, and Hg) concentrations were measured in each water sample. Data was analyzed using SPSS statistica software. Considerable temporal fluctuations in water quality indicators were detected in inlets, irrigation outflows, and edges over the research period. The findings revealed that NO3- -N, NH4+-N, and DRP in Sangilikandarawa reservoir during the northeast monsoon were close but not above the FAO (1985) maximum levels guidelines for irrigation water. pH, EC, TDS, and heavy metals (Cd, As, Pb, and Hg) in all the other tanks were within permitted values according to WHO drinking water quality standards and FAO (1985) guidelines for irrigation water. This finding further demonstrated that the consequences of surrounding land use on water pollution in inlet water canals linked to Sangilikandarawa and Nuwarawewa are greater. It could be concluded that a pollution management plan needs to be implemented in order to stop further pollution.

Constraints in culture-based fisheries of Sri Lanka and strategies for future development

In the fisheries sector, fisheries enhancement through culture-based fisheries (CBF) has been recognized as an environmentally friendly approach, which is bound to contribute to increasing food fish production, especially in developing countries. Through concerted efforts, Sri Lanka achieved considerable success in CBF development in small village reservoirs in the country. However, there are some constraints to achieve the full potential in the development of CBF in Sri Lankan inland waters, which require certain interventions. Despite the availability of a magnitude of small village reservoirs in the country, the full potential of utilization of these water bodies is not achieved mainly due to the inadequacy of stocking material at the correct time under the present strategy of fish fingerling production for stocking reservoirs. It is therefore imperative that effective intervention be in place for the establishment of backyard hatcheries using simple technologies to the self-help community groups in the rural areas. The CBF strategies in non-perennial reservoirs of the country are essentially dependent on the water availability in reservoirs following monsoonal rainfall patterns. Due to anomalies in monsoonal rainfall patterns under climate change scenarios, water availability in non-perennial reservoirs in the dry zone of Sri Lanka for CBF development is rather unpredictable. As such, there is a potential risk that the rural groups engaged in fry-to-fingerling production face the difficulty of selling fish fingerlings to CBF farming groups when the non-perennial reservoirs are not filled due to insufficient monsoonal rains. An alternative strategy to link fingerling-producing community groups with the agricultural farming communities in minor perennial reservoirs should be in place to prevent such potential financial losses of fingerling producers.

A GLM copula approach for multisite annual streamflow generation

The research presents a multisite annual streamflow generation model that combines the Generalized Linear Model (GLM), for determining the temporal structure, with copulas, for modelling the spatial dependence joint distributions. The performance of the GLM-Copula model was verified by comparing its ability to preserve historical features and simulate drought events with the multivariate auto regressive moving average (ARMA) model and the copula autoregressive (COPAR) model. The statistical measures adopted for the models’ performance evaluation include summary statistics (mean, standard deviation, maximum, minimum and skewness coefficient), temporal and spatial correlation, simulation of drought conditions (maximum number of years under drought condition) and copula entropy as a nonlinear measure of total association. The combined GLM-Copula model’s main advantages are that (i) it does not require data normalization; ii) it allows the modelling of the dependence structures with different probability functions; and (iii) it is capable of representing non-conventional parsimonious autocorrelation functions. The ability of the GLM-Copula approach to preserve the summary statistics from the historical data was similar to both benchmark models. However, the GLM-Copula was considerably better in reproducing the longest drought duration that was underestimated by the ARMA model and was better in reproducing the copula entropy than both benchmark models. The approach is proposed in its simplest form but can be easily upgraded by combining GLMs with numerical data or extended to predict future streamflow with the incorporation of exogenous climate variables that affect streamflow. The proposed model may be useful in future studies/applications where data normalization jeopardizes the replication of data or/and in drought dependent stochastic applications, like the definition of optimal operation rules of a perennial reservoir system or long-term hydropower dispatch.

Role of giant freshwater prawn (Macrobrachium rosenbergii) in livelihoods of the rural fishers of Northern Province of Sri Lanka

The overall objective of this study was to assess to what extent Macrobrachium rosenbergii culture in reservoir is sustainable and whether it has the potential to provide a livelihood option for reservoir fishers. Fisheries and socio-economic data collection were conducted from 2016 January to 2018 December in five perennial reservoirs in the Northern Province of Sri Lanka. Results revealed that culture-based fisheries and the introduction of M. rosenbergii in the five selected reservoirs have achieved considerable success and resulted in significant increases in fish production, income of fishers, availability of fresh fish for the rural communities and livelihood opportunities for fishing families. Socio-economic factors such as, age, fisheries experience, fish catch of the previous day, market value, household status and livelihood diversification influenced reservoir fishing. Low rainfall, strong wind, high temperature, over-growth of aquatic plants and algal blooms wildlife attacks and theft of fishing gear were identified as key stressors.

Diversity and Distribution of Fin-fish and Prawn Species Assemblages of the Catch in Five Perennial Reservoirs in Northern Province, Sri Lanka

Present study was carried out to assess the abundance and diversity of fin-fish and prawn species in the selected five reservoirs in the Northern Province, Sri Lanka. Fin-fish and prawns caught by multi-mesh gillnets, and rod and hooks, were sampled from January to December 2017. Relative abundance and diversity indices were calculated and, differences and similarities among reservoirs in different months were assessed. The hierarchical clustering was used in constructing dendrogram. Of the 27 finfish species and two freshwater prawn species identified in total, the highest number of species were observed in Muthayankattu reservoir (26 species) while Puthumurippu reservoir had the lowest (14 species). Oreochromis niloticus was the dominant species in all the reservoirs. Small reservoirs (Puthumurippu, Kalmadu and Muhathankulam) showed high Shannon-Weiner diversity index and evenness, though low in dominance index, compared to large reservoirs (Vavunikulam and Muthayankattu). Selective harvest methods, number of fishers and seasonal variation of hydro-climatic factors such as rainfall, strong wind and water level significantly influenced the diversity of fish species. Increasing fishing pressure and use of destructive fishing methods during low water level were the main contributors for diversity loss in the five perennial reservoirs studied.

Institutional Robustness of Culture-based Fisheries in Perennial Reservoirs of Sri Lanka

Institutional Robustness of Culture-based Fisheries in Perennial Reservoirs of Sri Lanka

Performance of <em>Macrobrachium rosenbergii</em> in perennial reservoirs: a comparative assessment of fisheries in five perennial reservoirs in the Northern Province of Sri Lanka

The giant freshwater prawn (Macrobrachium rosenbergii), was first introduced to the reservoirs in the Northern Province of Sri Lanka. Studies on the performances of introduced species in reservoirs are essential for development of fisheries and management. The objective of the present study was to evaluate and compare the performance of M. rosenbergii production in five selected perennial reservoirs. Primary data relating to the fisheries of the reservoirs and relevant socio-economic data were gathered through field data collection and questionnaire survey conducted in 2016 and 2017. Unit production of M. rosenbergii in 2017 in the Vavunikulam, Muthayankattu, Puthumurippu, Kalmadu and Muhathankulam reservoirs was 5.3 kg/ha, 3.2 kg/ha, 13.6 kg/ha, 21.8 kg/ha, 12.9 kg/ha, respectively with a farm-gate values of 6.84, 4.39, 2.1, 1.59, and 2.85 million Sri Lankan rupees, respectively. Relative abundance, economic (total farm-gate price) contribution and recapture rate of M. rosenbergii in the catch, ranged between 2.3%-20%, 13.5%-72.3% and 1.44%-6.49%, respectively across the reservoirs. Even though the recapture rate was low, catching of M. rosenbergii improved the livelihood of fishers while increasing their interest in fisheries. Size of the reservoir, stocking density, fishing intensity and gear specification, rainfall, wind and socio-economic factors significantly influenced the catch of M. rosenbergii in the selected reservoirs. The results showed that the introduction of M. rosenbergii as culture-based fisheries in the selected five reservoirs has achieved considerable success, particularly in terms of economic benefits.

First Report of Prunus domestica as the Host of a Phytoplasma Belonging to Group 16SrI, Subgroup B/L

HomePlant DiseaseVol. 103, No. 1First Report of Prunus domestica as the Host of a Phytoplasma Belonging to Group 16SrI, Subgroup B/L PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Prunus domestica as the Host of a Phytoplasma Belonging to Group 16SrI, Subgroup B/LA. Zwolińska, N. Borodynko-Filas, D. Nowaczyk, and B. Hasiów-JaroszewskaA. Zwolińska†Corresponding author: A. Zwolińska; E-mail: E-mail Address: a.zwolinska@iorpib.poznan.plhttp://orcid.org/0000-0003-2681-2915Search for more papers by this author, N. Borodynko-FilasSearch for more papers by this author, D. NowaczykSearch for more papers by this author, and B. Hasiów-JaroszewskaSearch for more papers by this authorAffiliationsAuthors and Affiliations A. Zwolińska † N. Borodynko-Filas D. Nowaczyk B. Hasiów-Jaroszewska , Institute of Plant Protection – National Research Institute, Virology and Bacteriology Department, Poznań, Poland. Published Online:31 Oct 2018https://doi.org/10.1094/PDIS-06-18-0963-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat In July 2016 and 2017, diseased plum trees (Prunus domestica L.) were observed in the orchard localized in the Wielkopolska region of Poland. The symptoms of witches’ brooms with internode shortening, axillary bud growth, and reduced leaf size indicated a potential phytoplasma infection. Samples of shortened shoots were collected from five symptomatic and five asymptomatic plants, respectively. DNA samples were extracted from 2 g of leaf tissues using a modified cetyltrimethylammonium bromide procedure (Maixner et al. 1995) and subsequently used as templates in nested polymerase chain reaction (PCR) for the amplification of genes encoding 16S rRNA; ribosomal proteins (rp) S19, L22, and S3 and elongation factor Tu (tuf) with primers P1/P7 followed by R16F2n/R16R2; rpF1/rpR1 followed by rp(I)F1A/rp(I)R1A and fTuf1/rTuf1 followed by fTufAY/rTufAY, respectively (Duduk et al. 2013; Martini et al. 2007; Schneider et al. 1997). Amplicons of correct sizes (1.2, 1.2, and 0.9 kb) were obtained from all the diseased plants tested (samples Plum1 to Plum5), respectively. No PCR products were obtained from the asymptomatic samples. All PCR products were ligated into pGEM-T Easy Vector Systems (Promega), and plasmid DNA was sequenced by an external company (Genomed, Warsaw, Poland). The 16S rDNA, tuf, and rp genes coding sequences from Plum1 to Plum5 were identical, and therefore one representative sequence of each region was deposited in GenBank under accession numbers MH061193, MH061368, and MH061366, respectively. The R16F2n/R16R2 (MH061193) primed fragment was subjected to in silico restriction digestion using iPhyClassifier, the online tool for phytoplasma classification (https://plantpathology.ba.ars.usda.gov/cgi-bin/resource/iphyclassifier.cgi). The collective restriction fragment length polymorphism patterns indicated that diseased plants were infected by ‘Candidatus Phytoplasma asteris’ of subgroup 16SrI-L. Next, the 385-bp barcode fragments of the EF-Tu gene from representatives of different phytoplasma groups were retrieved from the GenBank database. The phylogenetic analysis was performed based on those sequences and the tuf sequence obtained in this study using the neighbor joining algorithm of MEGA 7 software (https://www.megasoftware.net/). The 1.2-kbp DNA segment containing rp genes was also analyzed. In the phylogenetic trees, the Polish isolate of plum witches’ broom phytoplasma clustered together with ‘Ca. P. asteris’ representatives of ribosomal subgroup 16SrI-B and 16SrI-B/L. Based on all the performed analyses, the plum witches’ broom phytoplasma (PlumWB) was classified as a member of group 16SrI, subgroup B/L, which consists of two heterogeneous 16Sr RNA genes (Jomantiene et al. 2010). To our knowledge, this is the first report of plums infected with ‘Ca. P. asteris’ representing subgroup I-B/L in Poland, suggesting that fruit trees can be perennial reservoirs of the phytoplasma, which has great significance in the pathogen’s epidemiology.

Factors associated with illegal fishing practices in three perennial reservoirs in Sri Lanka

A study was conducted to investigate the socioeconomic and management factors affecting illegal fishing practices that cause an irreparable damage to the fish resources in Victoria, Sorabora and Ulhitiya reservoirs. A total of 368 fishers were surveyed representing all landing sites of the three reservoirs on their socioeconomic status and fishing practices. Illegal fishing gear confiscated and incidences of illegal fishing were quantified using records of relevant government authorities. Chi-square analysis was conducted to determine the association between involvement in illegal fishing and each of the socioeconomic and management factors. Linear logistic model analysis was performed to determine the odds and relative risk of factors affecting illegal fishing. Characteristics of fishers such as frequent consumption of alcohol, non-willingness to organize into a fisheries society and noncompliance with fisheries regulations were significantly associated with the engagement in illegal fishing in all the three reservoirs (p<0.05). In addition, in Victoria reservoir, those fishers holding positions in the Fisheries Society and voluntarily participating in official raids were found to be significantly less prone to engage in illegal fishing activities (p<0.05). In Ulhitiya, factors such as obtaining license and registration of boats and gear and fishing (full/part time) were significantly associated with illegal fishing (p<0.05). Tendency to be involved in illegal fishing was lesser among those who achieved better education (primary or higher) in Sorabora and Ulhitiya (p<0.05). Training programs were effective in reducing tendency for illegal fishing only in Sorabora fishing community (p<0.05). This study confirmed that a reservoir-specific co-management strategy is required as an effective management procedure to minimize illegal fishing practices in these reservoirs.

A comparison of the larvivorous habits of exotic Poecilia reticulata and native Aplocheilus parvus

BackgroundThe exotic fish Poecilia reticulata is promoted in the tropics as a biological control agent for aquatic pathogenic carriers, such as mosquitoes. Such control measures are often adopted blindly, ignoring the potential of native species and the adverse effects of introduced species. The present study was conducted to assess the diet composition of two species of fish, the native Aplocheilus parvus and exotic P. reticulata, and to assess the availability of food items in their natural environment in four types of aquatic systems. Diet composition was estimated using 24 h gut contents analysis, in a clay quarry pit and a perennial reservoir for A. parvus, and in a man-made canal and a second-order natural stream for P. reticulata. Food items in these environments were quantified by analyzing water samples collected every 2 h.ResultsThe diet of A. parvus in the clay quarry pit and reservoir consisted of adult or larval stages of Insecta, Maxillopoda and Malacostraca. In both habitats, A. parvus selectively fed on insect parts and insect larvae. The diet of P. reticulata consisted of filamentous algae, diatoms and detritus. The diet of A. parvus showed active selection of insectivore food items against their low availability. In contrast, the diet of P. reticulata showed consumption of food items in accordance with their availability in the environment. The highest mean number of food items in the gut for A. parvus was recorded around mid-day in the clay quarry pit, but no peak feeding time was identified in the perennial reservoir. For P. reticulata, peak feeding was recorded around mid-day in both the habitats.ConclusionIrrespective of the type of environment and rate of occurrence, A. parvus preferred insect and insect larvae, whereas P. reticulata consumed the most readily available food items. The active selection of insects by A. parvus suggests they may have value as a biological control agent.

Fisheries enhancements in inland waters in Sri Lanka with special reference to culture based fisheries: current status and impacts

Sri Lanka is endowed with more than 12,000 reservoirs. Depending on their hydrological regimes, they are broadly categorized into perennial and seasonal reservoirs and are secondarily used for the development of inland fisheries. This paper discusses the importance and status of culture-based fisheries (CBF) in reservoirs of Sri Lanka and assess the impacts of introduction of CBF. The CBF in seasonal reservoirs was initiated in the 1980s and it is well documented. There are around 200,000 ha of perennial reservoirs in Sri Lanka and CBF in perennial reservoirs is a recent development. Introduction of CBF into perennial reservoirs has resulted in significant increases in fish production, increased availability of fresh fish to rural communities, enhanced livelihood opportunities and income for fishers and strengthening the rural economy. Progress achieved so far in respect of seasonal reservoirs has not reached the envisaged levels.Nile tilapia, catla, rohu and mrigal are the main contributory species for fish production through CBF in perennial reservoirs. Although the contribution to fish catches is low, stocking of freshwater prawn (Macrobrachium rosenbergii) is financially feasible. Adequate stocking with suitable species, the existence of active Community Based Organizations (CBOs) and their involvement in planning and implementation of CBF, and the existence of a legal framework which facilitate implementation of activities pertaining to CBF are the key factors for successful implementation and sustainability of CBF in perennial reservoirs.

Climate Variability Adaptation Strategies: Challenges to Livestock Mobility in South-Eastern Burkina Faso

This research work aims to study the perceptions of pastoralists and agro- pastoralists on climate change impacts on mobile herding and the effectiveness of herders’ adaptive strategies within Kompienga Province, south-eastern region of Burkina Faso. In order to achieve this aim, survey data were retrieved from 271 respondents and analysed. From respondents’ perceptions, climate change is real and is negatively affecting forage availability (in quality and quantity); livestock production and reproduction performances; herders’ practices, their livelihoods and the cohabitation of herding and crop farming. To overcome the increasing constraints the pastoral herding is facing, sound and urgent actions need to be undertaken by Burkina Faso government. These actions include: 1) providing the grazing reserves with necessary facilities such as perennial reservoirs; 2) conducting research to improve breeds that would adapt to current climatic conditions; 3) encouraging and supporting gradual shift of herders from mobile herding to the sedentary breeding; 4) supporting and organizing forage production by farmers. At short term an effective cross-border framework could be created to seek for sound solutions to secure the mobility of herds within ECOWAS territory.

Salinity tolerant Aedes aegypti and Ae. albopictus-Infection with dengue virus and contribution to dengue transmission in a coastal peninsula.

Aedes aegypti and Ae. albopictus are major arboviral vectors that are considered to lay eggs, and undergo preimaginal development only in fresh water collections. However, recently they have been also shown to develop in coastal brackish water habitats. The ability of the biologically variant salinity-tolerant Aedes vectors to transmit arboviral diseases is unknown. We therefore, investigated the infection of salinity-tolerant Aedes mosquitoes with dengue virus (DENV) and analysed dengue incidence and rainfall data to assess the contribution of salinity-tolerant Aedes vectors to dengue transmission in the coastal Jaffna peninsula in Sri Lanka. Brackish and fresh water developing female Ae. aegypti and Ae. albopictus were tested for their ability to become infected with DENV through in vitro blood feeding and then transmit DENV vertically to their progeny. An immunochromatographic test for the NS1 antigen was used to detect DENV. Temporal variation in dengue incidence in relation to rainfall was analysed for the peninsula and other parts of Sri Lanka. Aedes aegypti and Ae. albopictus developing in brackish water, became infected with DENV through in vitro blood feeding and the infected mosquitoes were able to vertically transmit DENV to their progeny. Monsoonal rainfall was the discernible factor responsible for the seasonal increase in dengue incidence in the peninsula and elsewhere in Sri Lanka. Fresh water Aedes vectors are main contributors to the increased dengue incidence that typically follows monsoons in the Jaffna peninsula and elsewhere in Sri Lanka. It is possible however, that brackish water-developing Aedes constitute a perennial reservoir for DENV to maintain a basal level of dengue transmission in coastal areas of the peninsula during the dry season, and this supports increased transmission when monsoonal rains expand populations of fresh water Aedes.

Cost-benefit Analysis on Introduction of &lt;i&gt;Macrobrachium rosenbergii&lt;/i&gt; (De Man, 1879) in Puthumurippu medium perennial reservoir in Sri Lanka

Macrobrachium rosenbergii, a giant freshwater prawn, was newly introduced to Puthumurippu medium perennial reservoir in Kilinochchi district in June 2016 with the stocking of 100,000 post larvae (PL15) with the aim of improving livelihood of the fishermen by diversifying species in the reservoir. Return of M. rosenbergii was found to be high with a recapture rate of 2.5 % and return on investment of 360.6 % within one year study period. Income from harvesting M. rosenbergii improved the livelihood of fishers by increasing their income and interest in fisheries. Furthermore, the total yield increased with the increase in fishing effort during the study period. In addition, it was observed that male M. rosenbergii had a significantly high mass and growth rate compared to females on average. The results of this study indicated that M. rosenbergii stocking program was a cost effective and a successful venture in the development of livelihood of fishing community and fisheries production of the Puthumurippu reservoir.

In Situ and Satellite Observation of CDOM and Chlorophyll-a Dynamics in Small Water Surface Reservoirs in the Brazilian Semiarid Region

We analyzed chlorophyll-a and Colored Dissolved Organic Matter (CDOM) dynamics from field measurements and assessed the potential of multispectral satellite data for retrieving water-quality parameters in three small surface reservoirs in the Brazilian semiarid region. More specifically, this work is comprised of: (i) analysis of Chl-a and trophic dynamics; (ii) characterization of CDOM; (iii) estimation of Chl-a and CDOM from OLI/Landsat-8 and RapidEye imagery. The monitoring lasted 20 months within a multi-year drought, which contributed to water-quality deterioration. Chl-a and trophic state analysis showed a highly eutrophic status for the perennial reservoir during the entire study period, while the non-perennial reservoirs ranged from oligotrophic to eutrophic, with changes associated with the first events of the rainy season. CDOM characterization suggests that the perennial reservoir is mostly influenced by autochthonous sources, while allochthonous sources dominate the non-perennial ones. Spectral-group classification assigned the perennial reservoir as a CDOM-moderate and highly eutrophic reservoir, whereas the non-perennial ones were assigned as CDOM-rich and oligotrophic-dystrophic reservoirs. The remote sensing initiative was partially successful: the Chl-a was best modelled using RapidEye for the perennial one; whereas CDOM performed best with Landsat-8 for non-perennial reservoirs. This investigation showed potential for retrieving water quality parameters in dry areas with small reservoirs.

FIRST REPORT OF TOMATO INFECTIOUS CHLOROSIS VIRUS IN GLOBE ARTICHOKE ECOTYPES IN APULIA, SOUTHERN ITALY

Apulia (southern Italy) hosts a rich variety of globe artichoke ecotypes of high interest for breeding programs and industrial production. Most of the ecotypes are at risk of genetic erosion because of the high incidence of plant pathogens, which include infections from taxonomically different viruses. In the early autumn of 2014 and 2016 five samples were collected from each of the early-flowering ecotypes, Brindisino, Carciofo di Lucera, Francesina di Brindisi, Francesina di Trinitapoli, Locale di Mola, Nero di Ostuni, Tricasino, Troianella, Verde di Putignano, Violetto di Putignano and the late-flowering ecotypes Bianco di Taranto and Locale di Mola tardivo, and tested for viral infections by dot blot hybridization with Dig-labeled DNA probes and RT-PCR (Minutillo et al., 2012). In the five samples of the ecotypes Verde di Putignano, Violetto di Putignano, Nero di Ostuni and Troianella the hybridization signal revealed the presence of tomato infectious chlorosis virus (TICV) that in the ecotype Troianella was in mixed infection with artichoke Italian latent virus and turnip mosaic virus. TICV infection was confirmed by RT-PCR with TICV-specific primer pair for 5'- TCAGTGCGTACGTTAATGGG-3' and rev 5'-CACAGTATACAGCAGCGGCAG-3' (Minutillo et al. 2012). Amplicons from the ecotypes Verde di Putignano and Troianella were sequenced. Nucleotide sequence analyses revealed 99% identity with a TICV isolate from USA (accession No. FJ542306). Previous surveys detected TICV in globe artichoke in Liguria, Sardinia, Latium, Campania and Sicily but this is the first report of TICV in artichoke in Apulia and in the ecotypes Verde di Putignano, Violetto di Putignano, Nero di Ostuni and Troianella. Artichoke plants infected by TICV did not show symptoms and thus may act as perennial TICV reservoirs.

Impacts and Importance of Introduction of Culture-based Fisheries in Three Medium Sized Perennial Reservoirs in Sri Lanka

Impacts and Importance of Introduction of Culture-based Fisheries in Three Medium Sized Perennial Reservoirs in Sri Lanka