Growth,food efficiency,and biochemical composition of juvenile spotted babylon <Emphasis Type="Italic">Babylonia areolata</Emphasis> (Link) fed on conventional trash fish and a formulated moist diet

A 120-day feeding trial was conducted to determine growth, feeding efficiency, and biochemical composition of juvenile spotted babylon Babylonia areolata (initial mean weight of 1.48 ± 0.06 g) fed on conventional trash fish and a formulated moist diet in a flow-through grow-out system. The snails readily accepted the formulated moist diet and showed good growth and survival during the trial. There were no significant differences in specific growth rate, feeding efficiency, and survival between the snails fed on trash fish or the formulated moist diet. At the end of the experiment, biochemical analysis of the snail flesh showed significant differences in flesh quality, with the snails fed on trash fish having a significantly higher crude protein compared to those fed on the formulated diet, but there was little difference in crude lipid content. Whole body tissue of snails fed on trash fish had significantly higher total amino acid, essential amino acid, and non-essential amino acid levels compared to those fed the formulated diet. This study showed that the formulated moist diet can be readily used for B. areolata growout for maximizing growth, survival, and feeding efficiency; however, further research is needed to improve the flesh quality particularly amino acid and fatty acid levels before its suitability for B. areolata is assured.     

Distribution and diversity of benthic macroinvertebrate fauna in three repeated operating ages of the blood cockle Anadara granosa cultivation in Bandon Bay,Suratthani Province,Southern Thailand

The diversity, distribution and species richness of benthic macroinvertebrate fauna as well as benthic environments were examined in the blood cockle Anadara granosa cultivations at Ban Don Bay, Suratthani Province, Southern Thailand during the summer season of April and rainy season of October in 2017. The cockle cultivations of three repeated operating ages (<5 years: S1; 5–10 years: S2; more than 10 years: S3) were selected for the study, and the sampling sites were allocated at the centre of the farm. Results indicated that there were significant differences in species number, individual number and evenness index of benthic macroinvertebrate fauna found in the two sampling seasons (p < .05) and significant differences in individual number and evenness index were found among the sampling sites (p < .05). Significant differences in pH, total phosphorus levels, sulphide levels and organic matter of sediment were found between the sampling seasons (p < .05) and differences in total nitrogen level, organic matter and clay content were found among the sampling sites (p < .05). Among the independent variables analysed, correlation analysis showed no relationship between diversity index, species richness index and evenness index and the abiotic variables (p < .05). The results of the present study suggest that the distribution and diversity variations of the benthic macroinvertebrates community fauna are not affected by all sediment parameters in various repeated cultivation of the blood cockle Anadara granosa in Bandon Bay, Suratthani Province.     

Growth and water quality for growing-out of juvenile spotted Babylon, Babylonia areolata, at different water-exchange regimes in a large-scale operation of earthen ponds

Growth and water quality for growing-out of juvenile spotted Babylon, Babylonia areolata, were determined at three water-exchange regimes of 7-, 15- and 30-day intervals in large-scale operation of earthen ponds over a 5-month period. Results showed that growth was significantly different among the water-exchange treatments (P < 0.05). The higher body weight gains and shell length increments were observed in snails held at water exchange of 7- and 15-day intervals when compared with those held at water exchange of 30-day intervals. At the end of the experiment, average body weight gains were 4.22, 3.73 and 2.77 g for snails held in water-exchange treatments of 7-, 15- and 30-day intervals, respectively, and 16.63, 15.04 and 13.78 mm for those of shell length increments, respectively, The average final survivals were 83.60, 80.90 and 74.20% for snails held in water-exchange treatments of 7-, 15- and 30-day intervals, respectively. Seawater temperature, salinity, pH, dissolved oxygen, nitrite–nitrogen and ammonia–nitrogen had gradually changed throughout the culture period for all water-exchange treatments. With one exception, the total alkalinity showed the greatest changes during the culture period for all water-exchange treatments ranging from 58.67–97.50 mg/l.     

Effects of Water Depth and Water Flow Duration on Growth and Survival of Juvenile Spotted Babylon (Babylonia areolata) Cultured in a Flow-Through System

Eight growth trials of juvenile B. areolata at different water depths (20 and 50 cm) and water flow durations (6, 12, 18, and 24 h) were conducted in a flow-through culture system over 5 months. One-way ANOVA performed on each growth data set showed that there were significant differences among water depth (WD) and water flow duration (WFD) treatments (P < 0.05). The highest weight gain (6.29 g /snail) was found in snails reared in the treatment of WD₅₀ /WFD₂₄, followed by those from WD₅₀ /WFD₁₈ (6.15 g/snail), WD₅₀/WFD₁₂ (5.90 g/snail), WD₅₀ /WFD₆ (5.83 g/snail), WD₂₀ /WFD₂₄ (5.86 g/snail), and WD₂₀ /WFD₁₈ (5.87 g /snail), while the lowest one was found in WD₂₀ /WFD₆ (5.52 g/snail) and WD₂₀ /WFD₁₂ (5.57 g/snail). The relative weight gain (RWG) and individual weight gain (IWG) of the snails showed similar trends as the weight gain. Final survival exceeded 95% for all treatments. Based on all criteria, the best growth performances of juvenile spotted babylon were found in the WD₅₀ /WFD₁₈ and WD₅₀ /WFD₂₄ treatments, followed by the treatments of WD₅₀/WFD₁₂, WD₅₀ /WFD₆, WD₂₀ /WFD₂₄, and WD₂₀ /WFD₁₈; the lowest growth was found in WD₂₀ /WFD₆ and WD₂₀ /WFD₁₂.     

Combined effects of water exchange regimes and calcium carbonate additions on growth and survival of hatchery-reared juvenile spotted babylon (Babylonia areolata Link 1807) in recirculating grow-out system

To determine a suitable culture environment to maximize growth and survival, the hatchery‐reared juvenile spotted babylon, Babylonia areolata, were held in plastic rearing tanks at four calcium carbonate additions of 0, 100 and 300 g tonne^?1, and four water exchange regimes of 0‐, 15‐, 30‐ and 60‐day intervals in a recirculating grow‐out system for 120 days. The results clearly showed that growth was greatest between water exchange regimes of 15‐ and 30‐day intervals and all calcium carbonate additions, with water exchange regimes of 0‐ and 60‐day intervals resulting in poor growth. Final survival was highest between water exchange regimes of 15‐ and 30‐day intervals, and all calcium carbonate additions, with water exchange regimes of 0‐day intervals and all calcium carbonate additions resulting in high mortalities. This study showed that water exchange regimes had a stronger influence on the growth of juvenile B. areolata than calcium carbonate additions. It is recommended that B. areolata juveniles be maintained within the water exchange regimes range of 15–30‐day intervals and at calcium carbonate additions between 0 and 500 g tonne^?1, providing optimum conditions for production of this species in a recirculating grow‐out system.     

Economic analysis of a pilot commercial production for spotted babylon, Babylonia areolata (Link 1807), of marketable sizes using a flow-through culture system in Thailand

This article examines the economic considerations involved in the production of spotted babylon (Babylonia areolata) in Thailand. A financial analysis of the construction and operating costs of a pilot commercial production of spotted babylon of marketable sizes is provided, based upon proven practical techniques and production data for a flow‐through growout system. The investment required for a spotted babylon growout hatchery producing 990 kg per year is estimated to be US$4528.8. The annual cost of operating such a hatchery is estimated to be US$4624.1. The cost of producing 990 kg of marketable‐size spotted bablyon with a survival rate of 95% is estimated to be US$4.91 per kg of snails produced. Cash flow analysis showed that a constant selling price of US$5.8 kg^?1 results in positive cash flow by year 4. The proposed enterprise is marginally feasible if cost can be considerably reduced by targeting production and integrating hatchery and growout operations.     

Growth trials for polyculture of hatchery-reared juvenile spotted babylon (Babylonia areolata) and sea bass (Lates calcarifer) in a flow-through sea water system

Juvenile spotted babylon (Babylonia areolata) and sea bass (Lates calcarifer) were cultured in 11.5‐m³ indoor rearing tanks supplied with flow‐through of ambient natural sea water over a 120‐day experiment. Each species, stocked at the following densities for the following treatments, was tested with three replicates per treatment: 5000 B. areolata per tank (Treatment 1); 200 L. calcarifer per tank (Treatment 2); and 5000 B. areolata plus 200 L. calcarifer per tank (Treatment 3),. The average growth (length and weight), feed conversion ratio and total production of spotted babylon and sea bass from Treatment 3 were not significantly different from those of Treatment 1 and 2 (P > 0.05). Average survival rates for both spotted babylon and sea bass exceeded 95% for all treatments.     

Effects of extensive bottom cultivation of tropical oyster <Emphasis Type="Italic">Crassostrea belcheri</Emphasis> on benthic invertebrate community structure in Ban Don Bay,Suratthani Province,Southern Thailand

The diversity, distribution, and species richness of benthic invertebrates were examined under extensive bottom cultivation of the tropical oyster Crassostrea belcheri during the summer of 2015 at Ban Don Bay, Suratthani Province, Southern Thailand. Oyster farms that had been operating for 25 years were selected for the study, and four sampling sites were allocated along each transect as (i) at the center of the farm, (ii) inside the farm, (iii) at the farm boundary, and (iv) a reference site. Results indicated that a total of 23 families and 28 species of benthic invertebrate taxa were recorded from the four sampling sites, and the macrobenthic invertebrates inhabiting all study sites consisted mainly of gastropods (11 species), polychaetes (11 species), and bivalves (8 species). No significant differences in total density, diversity index, evenness index, and species richness index of benthic invertebrates were found among each sampling site (P?>?0.05). Significant differences in total nitrogen, nitrate, nitrite, total ammonia, sulfide, total phosphorus, organic matter, and grain sizes of sediment were found among each sampling site, but no significant differences in pH and total nitrogen were found. Among the independent variables analyzed, correlation analysis showed relationships between benthic diversity indices and abiotic variables. There were no clear patterns of differences in the detrimental environmental effects between sampling site locations, which indicated a minimal ecological impact of oyster cultivation.     

Pilot study on polyculture of juveniles spotted babylon, Babylonia areolata, with milkfish, Chanos chanos, to marketable sizes using large-scale operation of earthen ponds in Thailand

Growth, production and economic analysis was performed for the polyculture of juveniles spotted babylon, Babylonia areolata, and milkfish, Chanos chanos, to marketable sizes using a large‐scale production of earthen ponds in Thailand. The analysis was based on actual cost and production data from a pilot commercial‐scale farm. A total farm area of 0.8 ha was comprised of 0.3 ha grow‐out earthen ponds, a 0.4 ha seawater reservoir, and a 0.08 ha accommodation and office. Each pond was stocked with spotted babylon juveniles of 0.3 g initial body weight at a density of 200 snails m^?2, and they were harvested at a 7‐month period, at an average body weight of 4.6 g for a total yield per production cycle of spotted babylon and milkfish of 9875 and 6875 kg ha^?1 respectively. Based on farm data and harvest data used in this study, initial investment requirement was estimated to be $4837. The ownership cost and operating cost per production cycle were $2241 and $18 501 respectively. Total cost per production cycle was $20 742. The cost of producing spotted babylon marketable sizes in this grow‐out farm design was $6.56 kg^?1. The enterprise budgets based on the price of spotted babylon at a farm gate in 2003 of $9.00 kg^?1 results in gross return, net return, return to capital and management, and return on investment of $31 190, $10 448, $12 689 and 2.62 respectively. Milkfish was not calculated for any returns because they were less than marketable sizes.     

Effects of feeding rates on the growth, survival and feed utilization of hatchery-reared juvenile spotted babylon Babylonia areolata Link 1807 in a flowthrough seawater system

The effects of feeding levels on the growth, survival and feed utilization of hatchery-reared juvenile Babylonia areolata Link 1807 were assessed at four daily rations of 3%, 5%, 10% and 15% of body weight. Three duplicated groups of juveniles (mean initial body weight 0.26 ± 0.3 g) were stocked into indoor rearing tanks supplied with a flowthrough system of ambient natural seawater for 150 days. Growth in body weight differed significantly (P < 0.05) among the various feeding levels. Final body weight of individual snails increased with increased feeding ration at a particular ration level. Meanwhile, increasing the daily ration to 10% and 15% significantly improved growth and feed utilization efficiency. The food conversion ratios (FCRs) for the 3% and 5% feeding levels were significantly lower than those for the other feeding levels. Final survival was best at feeding levels of 10% and 15% of body weight, ranging between 96.9% and 97.3%, but was very poor at the 3% and 5% feeding levels, ranging from only 49.5% to 54.8%.