The development of a saline tolerant tilapia strain able to grow fast is of importance in the Philippines, where 240 000 ha of brackish water ponds are available. To this end, founder hybridization between Oreochromis niloticus (with favorable growth traits) and O. mossambicus (with favorable salinity tolerance traits) was performed and followed by backcrossing with O. mossambicus to develop a strain highly tolerant to saline environments. Genetic selection for growth performance was subsequently conducted.
Spatial and temporal variations of the demersal fisheries resources of Malaysia were studied using multivariate analysis of their abundance (biomass) from research trawl surveys in relation to geographical and environmental parameters. TWINSPAN results indicate that the demersal resources of Malaysia can be geographically divided into five major species assemblages. Two assemblages are in Peninsular Malaysia and three assemblages are in Sabah and Sarawak waters.
The rural populations of southern Bangladesh are some of the most vulnerable communities in the world to the future impacts of climate change. They are particularly at risk from floods, waterlogged soils, and increasing salinity of both land and water. The objective of this project was to analyze the vulnerability of people in four villages that are experiencing different levels of soil salinity.
A summary is presented of studies undertaken regarding the salinity tolerance of tilapias. The implications of thefindings to the culture of tilapias in Taiwan are considered.
The Mekong River delta of Vietnam supports a thriving aquaculture industry but is exposed to the impacts of climate change. In particular, sea level rise and attendant increased flooding (both coastal and riverine) and coastal salinity intrusion threaten the long-term viability of this important industry. This working paper summarizes an analysis of the economics of aquaculture adaptation in the delta, focusing on the grow-out of two exported aquaculture species—the freshwater striped catfish and the brackish-water tiger shrimp.
The feasibility of semi-intensive culture of Penaeus monodon in low saline environment was investigated by comparing the growth and production in low (0.16-6.52 ppt) and high (4.60-19.42 ppt) saline areas at two stocking densities (10.5 and 16 individuals/m super(2)). After 135 days of culture, yield of shrimp in low and high stocking densities was 1563.37 kg/ha and 2274 kg/ha, respectively, in low saline ponds, and 1173.00 and 1974.00 kg/ha, respectively in high saline ponds.
Based on on-farm surveys implemented in the Ganges Delta in Bangladesh and the Mekong Delta in Vietnam, the dynamics of shrimp aquaculture in salinity-influenced coastal areas were analysed. Qualitative data were collected through interviewing both individual and group farmers in 2005 and 2006, as well as key informants and value chain stakeholders, to obtain an overview of the dynamics of salinity-influenced aquaculture in these two deltas.
Oreochromis niloticus was subjected to transportation stress to investigate hepatic glycogen levels and mortality as indices of stress. Mortalities lasted up to three days after transportation, except in highly aerated samples. Heptic glycogen levels in transported fish were significantly lower in the controls. Stress appeared to be more intense when fish were transported at a high density and in a high salinity medium.
The success of induced spawning for the production of fish seed depends on many factors which affect hatchery conditions. This paper discusses the results of an investigation on the effects of six different levels of salinity on the fertilization and hatching of Heterobranchus bidorsalis eggs. The results indicate that spermatozoa of H. bidorsalis can survive under a wide range of saline concentrations, with survival increasing with an increase in salinity from 0 to 0.4% and then decreasing as the level of salinity increases. Survival was optimum of 0.4% saline concentration.
The aims of this project were to develop large scale breeding and rearing methods for sandfish (Holothuria scabra) for commercial culture and/or restocking. Wild collected sea cucumbers were initially difficult to spawn, but after a period in earthen ponds or seabed pens could be induced year-round, using temperature changes, emersion, treatment of water with UV light, and addition of dry phytoplankton. Numerous batches of larvae were reared to settlement and to larger sizes using simple hatchery methods.