Changes in Water Quality and Soil Property in the Rice–Freshwater Animal Co-Culturing System

This study investigated the effects of integrating various fish species in a rice field co-culture system on water quality and soil properties. The species included common carp (Cyprinus carpio), Nile tilapia (Oreochromis niloticus), silver barb (Barbonymus gonionotus), snakeskin gourami (Trichopodus pectoralis), and giant freshwater prawn (Macrobrachium rosenbergii). The key water quality parameters measured included water temperature, dissolved oxygen, pH, transparency, ammonia, and nitrite. Soil properties were evaluated through pH, electrical conductivity, organic matter, nitrogen, phosphorus, and potassium. All the selected aquatic animals showed high adaptability in co-culture systems, with survival rates exceeding 80%. Additionally, rice yields increased by approximately 16%, with the highest yield observed in plots stocked with prawns. The results indicated that the presence of aquatic animals enhanced nutrient cycling, leading to significant improvements in both water quality and soil fertility. Differences in water quality and soil properties throughout the culture period were specific to the species present. These findings suggest that rice-fish co-culture systems serve as an effective nature-based solution for enhancing productivity, sustainability, and food security

Biologies des deux principales espèces de poissons et des modèles assemblage de poissons et d'approches de modélisation dans les régions tropicales des bassins fluviaux (le cas de la rivière Ping bassin, de la Thaïlande)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Yield, growth and mortality rate of the Thai river sprat, Clupeichthys aesarnensis, in Sirinthorn Reservoir, Thailand

The Thai river sprat, Clupeichthys aesarnensis Wongratana, is a clupeid with a short life span, and supports artisanal fisheries in a number of reservoirs in the Mekong Basin. The growth parameters, mortality rates and the status of the Thai river sprat in Sirinthorn Reservoir (28 800 ha), NE Thailand (15&deg;N; 105&deg;E), are presented. The fishery is based on lured lift-nets, operated 7&ndash;14 days in the new moon period, September to April each year. It was shown that the von Bertalanffy growth function (VBGF) model was Lt (mm) = 78.43[1 &minus; exp{&minus;0.211[t &minus; (&minus;0.7996)]}] and its growth conformed to an isometric pattern. Natural mortality rate (month&minus;1) was 0.13 month&minus;1. Total mortality rates ranged from 0.69 to 1.53 month&minus;1 depending on the weather and the fishing season. Recruitment was continuous throughout the year but peaked in June and July. The yield per recruit model indicated that the exploitation rate of this fishery is probably too high.<br /

Chronicle of marine fisheries in the Gulf of Thailand: variations, trends and patterns

1302-1309A comprehensive picture of marine fisheries in the Gulf of Thailand (GoT), within Thailand’s boundary, has been described by using fish landing data for 26 years, between 1984 and 2009. Thirty-five (35) species/groups of fish landings were used in analysis. Rastrelliger brachysoma showed the lowest long-term variation (CV) in fish landings at 15.53% and the highest CV was observed in Lates calcarifer at 146.16%. The relationship between CV and fish landings showed a negative trend with a high correlation (r = 0.62) and was associated with species life-history strategies. For short-term variations, the means of the relative variation (28%) were higher than the absolute variation (25%), indicating a higher uncertainty when catches are low. Three trends in fish landings were analyzed by Spearman’s rank correlation. Seven (7) and 3 species/groups trended to decrease and increase, respectively, over the studied period. Meanwhile, 15 species/groups showed a trend of inversion, i.e. increased then decreased. The self-organizing map was used to cluster patterns of fish landings, which indicated temporal trends of chronological order, i.e. 1985-1990, 1992-1998, 1999-2007 and 2008-2009