2019 - Applied

Pre-imaginal development of Aedes aegypti in drains containing polluted water in urban cities in Sri Lanka

2022-09-20T10:16:57Z

Pre-imaginal development of Aedes aegypti in drains containing polluted water in urban cities in Sri Lanka Chandrasiri, P.K.G.K.; Fernando, H.S.D.; De Silva, B.G.D.N.K Dengue control in Sri Lanka targets the removal or treatment of fresh water bearing containers that provide breeding sites for Ae. aegypti. Health authorities have raised concern that the incidence level of dengue remains high in urban settings due to ignorance of dengue mosquito larval surveillance on polluted water drains. The present study was designed to evaluate the presence of Ae. aegypti in the polluted water drains in some urban areas in the country. A preliminary entomological survey was carried out in urban areas from Chilaw to Galle and further studies were carried out in the drainswith pollutedwater that marked the presence of Ae. aegypti larvae. Presence of Ae. aegypti was recorded in drains containing polluted water in Galle city for the first time in Sri Lanka. The most commonly observed species in the preliminary survey was Cx. quinquefasciatus (97.5%) followed by Cx. gelidus (0.99%), Ae. albopictus (0.62%) and Ae. aegypti (0.42%). Water quality characteristics revealed low dissolved oxygen and high conductivity with visible organic pollutants. Constant insecticide pressure and the destruction of the breeding sites through source reduction in vector control campaigns compel the mosquito to adapt to new ecological niches. Therefore, appropriate surveillance and control measures should be implemented by health authorities to control vector mosquitoes and lower the disease burden.

Effects of culture conditions on growth and survival of Poecilia sphenops and Poecilia reticulata

2022-09-20T09:51:43Z

Effects of culture conditions on growth and survival of Poecilia sphenops and Poecilia reticulata Sirimanna, S. R.; Dissanayake, C. Poecilia sphenops and P. reticulata are considered as two most popular and high demanding freshwater ornamental fish species globally. The effects of feeding frequency, feed protein level, photoperiod and salinity on growth and survival of these species and the effect of sex ratio on fecundity were studied under laboratory conditions from January to December 2016. Although there was no any significant impact of feeding frequency on growth and survival of these species, feed protein content affected significantly on their growth. Fry fed with newly hatched Artemia, commercial larval feeds and Chlorella sp. showed no significant impact on growth. Poecilia sphenops and P. reticulata could tolerate salinity up to 10 and 25 ppt, respectively. Fish exposed to 8 hrs photoperiod reported significantly lower growth than those who were exposed to 12 and 24 hrs photoperiods. The ideal female: male sex ratio for commercial stocking of P. sphenops and P. reticulata was 3:2.

Sea cucumber fishing pattern and the socio-economic characteristics of fisher communities in Sri Lanka

2022-09-20T09:24:04Z

Sea cucumber fishing pattern and the socio-economic characteristics of fisher communities in Sri Lanka Nishanthan, G.; Kumara, A.; Prasada, P.; Dissanayake, C. Sea cucumber fishing pattern and the social and economic characteristics of sea cucumber fisher communities in the north, north-west and north-east regions of Sri Lanka were assessed using the data collected from November 2015 to January 2017. A total of 9 sea cucumber species is landed in these areas using three fishing methods; diving (SCUBA and breath-hold), gleaning and surrounding nets. SCUBA diving is the dominant fishing method and SCUBA divers do both day and night fishing reporting the highest catch rates (CPUE ± SD in numbers/person/day) than the other fishers (p<0.05; ANOVA). Gleaning is entirely carried out by fisherwomen in the northern region whereas 28 surrounding nets are used targeting low-value Stichopus naso. CPUE found to be varied with respect to species, region and fishing method (p<0.05; ANOVA). Bohadschia vitiensis made the highest percentage contribution (61.3%) to the total sea cucumber landings during the study period. Among all fishers, SCUBA divers reported the highest average net monthly income. Men play a dominant role in sea cucumber fishing (98%), processing (99%) and marketing (100%). Fishermen in the age range of 25–67 yr, having only primary education mainly involved in the sea cucumber industry. The sea cucumber value chain consists of fishers (∼2000), middlemen (12), processors (16) and exporters (7). A significant increase in overall price development from fishers to the exporters was reported for all 9 species (p<0.05; ANOVA). Fishers received a proportionally higher share of the end-market price mainly for low-value Bohadschia spp. Although fishers receive disproportionately low returns compared to other value chain players, 47.8% of fishers showed high satisfaction towards the prices they received from buyers. However, 83.6% of fishers are not satisfied with existing management measures. Apart from strengthening the existing management measures, this information is important to update the regional and global sea cucumber statistics.

Role of CuAIO2 as an absorber layer for solar energy converter

2022-09-20T05:39:46Z

Role of CuAIO2 as an absorber layer for solar energy converter Som, N. S.; Sharma, V.; Mankad, V.; Attygalle, M. L. C.