Empirical Equations for Estimation of Transmission Losses Based on Field Measurements in Ephemeral Streams

The Second International Symposium on Flash Floods in Wadi Systems: 25-27 October 2016. Technische Universität Berlin, Campus El Gouna, Egypt

Highly Flexible Rainfall-Runoff Model Using Multiple Spreadsheets

The Second International Symposium on Flash Floods in Wadi Systems: 25-27 October 2016. Technische Universität Berlin, Campus El Gouna, Egypt

Time series analysis of remotely sensed water quality parameters in arid environments, Saudi Arabia

The monitoring of inland water resources in arid environments is an essential element due to their fragility. Reliable prediction of the water quality parameters helps to control and manage the water resources in arid regions. Water quality parameters were estimated using remote sensing data acquired from the beginning of 2017 until the end of 2018. The prediction of the water quality parameters was comprehended by using an adjusted autoregressive integrated moving average (ARIMA) and its extension seasonal ARIMA (S-ARIMA). Maximum Chlorophyll Index (MCI), Green Normalized Difference Vegetation Index (GNDVI) and Normalized Difference Turbidity Index (NDTI) were the tested water quality parameters using Sentinel-2 sensor on temporal resolution basis of the sensor. Results indicated that the implementation of the ARIMA model failed to sustain a reliable prediction longer than one-month time while S-ARIMA succeeded to maintain a robust prediction for the first 3 months with confidence level of 96%. MCI has its ARIMA at (1,2,2) and S-ARIMA at (1,2,2) (2,1,1)6, GNDVI has its ARIMA at (2,1,2) and S-ARIMA at (2,1,2) (2,2,2)6, and finally, NDTI has its ARIMA at (2,2,2) and S-ARIMA at (2,2,2) (1,1,2)6. The accuracy of S-ARIMA predictions reached 82% at 6-month prediction period. Meanwhile, there was no solid prediction model that lasted till 12 months. Each of the forecasted water quality parameters is unique in its prediction settings. S-ARIMA model is a more reliable model because the seasonality feature is inherited within the forecasted water quality parameters. © 2020, Springer Nature B.V

Lobster aquaculture development in Vietnam and Indonesia

Development of spiny (rock) lobster aquaculture is of special interest because market demand continues to increase while capture fisheries production remains static and with little likelihood of any increase. This chapter provides a synopsis of information about the history, development, status and future of tropical spiny lobster aquaculture with a particular focus on Vietnam and Indonesia, where considerable development has already occurred. Vietnam is the only country in the world where farming of lobsters is fully developed and commercially successful. The Vietnamese industry is based on a natural supply of seed lobsters – the puerulus stage, as hatchery supply is not yet available due to the difficult technical demands of rearing spiny lobster larvae in captivity. Vietnam currently produces around 1,600 tonnes of premium grade lobsters, primarily of the species Panulirus ornatus, that are exported to China where price is greatest. The industry is valued at over $US120 million. That success led to significant interest in Indonesia where a fishery for seed lobsters has become well developed, with a catch 10 to 20 times greater than that of Vietnam. However, growout of lobster in Indonesia remains insignificant due to adverse government policy and lack of farmer knowledge and skills. The seed lobsters available in Indonesia are primarily Panulirus homarus, a species with excellent production characteristics like P. ornatus, although with lesser value. Extraordinarily high abundance of naturally settling seed lobsters is apparent in selected areas due to a confluence of suitable conditions that create a high concentration of late stage larvae near the coast. These areas have been termed hotspots, as the availability of settling seed is much higher than other areas. Such hotspots are now recognized for the central northern coast of Vietnam – supplying their growout industry and the central southern coast of Indonesia. Natural mortality of the seed lobsters in these areas is correspondingly high due to insufficient settlement habitat and fish predation. Consequently, responsible fishing of these seed is sustainable, providing a valuable resource that can be on-grown for benefit of impoverished coastal communities. Innovative and inexpensive techniques have been developed to effectively catch the seed as they swim towards the coast seeking suitable habitat. In Vietnam, the seed are typically sold by fishers to dealers, who aggregate supplies and then on-sell to nursery farmers. Nursing consists of rearing the seed lobsters in small suspended or submerged cages, with a diet of fresh seafood – crabs, mollusc and fish. Advanced juvenile lobsters are produced that are in turn on-sold to growout farmers who stock them to larger floating cages, suspended from simple floating frames. The economics involve relatively low capital and operating costs, and production of high value product, that provides significant economic and social benefit to the communities involved. Although several health and disease issues have impacted spiny lobster farming, they can be effectively managed through good nutrition and husbandry. Market demand for spiny lobster from China is strong and growing, far exceeding supply. There appears to be great scope for much larger farm production of spiny lobsters with little impact on price. The future for tropical spiny lobster aquaculture appears to be very positive, particularly for developing countries in the Asian region, where seed are available, suitable growout locations are present and where costs of production are relatively low. It is expected that lobster aquaculture will continue to develop in the region, expanding beyond Vietnam and Indonesia