4 research outputs found
Underwater Weight Estimation of Three Sea Cucumber Species in Culture Tanks Using Image Analysis and ArUco Markers
No full textSea cucumbers play a vital role in marine and coastal ecosystems, with some species holding significant economic value. Accurate growth assessment, particularly weight estimation, is crucial for their management and conservation. However, direct measurement poses challenges, as sea cucumbers expel internal fluids when handled, altering their body size and weight. This study evaluates the effectiveness of image analysis combined with ArUco markers to estimate the weight of three economically and ecologically important sea cucumber species found in Thailand: black sea cucumber (Holothuria leucospilota), pink warty sea cucumber (Cercodemas anceps), and sandfish (Holothuria scabra). The proposed method demonstrated high accuracy, with R2 values of 0.9699, 0.9774, and 0.9882, respectively. Furthermore, no significant differences (p > 0.05) were observed between traditional hand measurements and image-based assessments, with relative errors of 7.71 ± 4.30% for black sea cucumber, 5.06 ± 3.37% for pink warty sea cucumber, and 4.50 ± 3.23% for sandfish. Unlike deep learning, which requires large datasets and high computation, this simple, cost-effective, and adaptable method highlights the potential of image analysis combined with ArUco markers as a non-invasive and accurate tool for estimating sea cucumber weight. This approach minimizes stress on the animals and can be extended to other aquatic species. However, challenges such as shadows, water turbidity, and the presence of similarly shaped objects near sea cucumbers should be considered when applying this technique in field conditions
Nitrogen Budget and the Effects of Sea Grape (Caulerpa lentillifera) Density on the Water Quality and Growth Performance of Asian Seabass (Lates calcarifer) in a Polyculture System
No full textThe nitrogen budget and the effects of varying densities of sea grape (Caulerpa lentillifera) on water quality and the growth performance of Asian seabass (Lates calcarifer) in a polyculture system were evaluated. Four treatments were tested, each stocked with 20 fish (average weight: ~20 g; density: 2.66 kg/m3). Treatment 1 (control) contained no sea grapes, while treatments 2, 3, and 4 included 100, 200, and 400 g of sea grapes, corresponding to 0, 667 g/m3, 1333 g/m3, and 2666 g/m3, respectively. Significant (p < 0.05) reductions in total ammonia nitrogen (TAN), total suspended solids (TSS), and turbidity were observed with increasing sea grape density; however, no significant differences (p > 0.05) were found among the three sea grape treatments. Higher sea grape densities increased nitrite (NO2–N) and nitrate (NO3–N) concentrations due to enhanced nitrification. Approximately 65% of the nitrogen input originated from feed, but only 47.78–48.96% was assimilated into fish biomass. Nitrogen losses included 1.17–1.46% via water exchange and final drainage, while 45.27–50.76% was likely retained in sediments, volatilized, or lost through denitrification. Sea grapes effectively absorbed total nitrogen (TN), demonstrating their potential as biofilters for improving water quality without compromising fish growth performance. The optimal density was 100 g of sea grapes per 2.66 kg/m3 of seabass biomass, offering a sustainable strategy to enhance productivity while mitigating environmental impacts
Influencia del clima en la calidad del agua de mar y la producción de mejillón verde
No full textThis study aimed to investigate the relationships between atmospheric parameters, seawater quality and green mussel production which were cultured in pond, estuary and coastal areas. Seawater and mussel samples were collected from mussel farms in the inner Gulf of Thailand from January to December 2019. Climate data were obtained from the Thai Meteorological Department. The correlations between selected atmospheric and seawater parameters were developed using linear and non-linear models. The influence of seawater quality on mussel production was evaluated using principal component analysis and stepwise multiple linear regression. The effects of atmospheric variation on green mussel productivity were simulated. The results showed that high air temperature and rainfall caused an increase in seawater temperature and a decrease in salinity, respectively. It was observed that the most influential factors affecting mussel production were nutrients and dissolved oxygen in ponds, temperature and salinity in estuaries, and nutrients and pH in coastal areas. The simulation indicated that mussel production can deteriorate when air temperature reaches 34°C and rainfall is higher than 200 mm per month. Our results suggest that under climate change events, locations with less riverine influence can provide higher mussel productivity. These results can be used as a guideline for farmers during a climate change event.Esta investigación tuvo como objetivo investigar las relaciones entre los parámetros atmosféricos, la calidad del agua de mar y la producción de mejillones verdes que se cultivaron en estanques, estuarios y áreas costeras. Se recolectaron muestras de agua de mar y mejillones de granjas de mejillones en el interior del Golfo de Tailandia de enero a diciembre de 2019. Los datos climáticos se obtuvieron del Departamento Meteorológico de Tailandia. Las correlaciones entre parámetros atmosféricos y de agua de mar seleccionados se desarrollaron utilizando modelos lineales y no lineales. La influencia de la calidad del agua de mar en la producción de mejillones se evaluó mediante análisis de componentes principales y regresión lineal múltiple paso a paso. Se simularon los efectos de la variación atmosférica sobre la productividad del mejillón verde. Los resultados mostraron que la alta temperatura del aire y las precipitaciones provocaron un aumento de la temperatura del agua de mar y una disminución de la salinidad, respectivamente. Se observó que los factores más influyentes que afectaron la producción de mejillón fueron los nutrientes y el oxígeno disuelto (OD) en los estanques; temperatura y salinidad en estuarios; y nutrientes y pH en zonas costeras. La simulación indicó que la producción de mejillón puede deteriorarse cuando la temperatura del aire alcanza los 34°C y la precipitación supera los 200 mm por mes. Nuestros resultados sugieren que, bajo eventos de cambio climático, los lugares con menos influencia fluvial pueden proporcionar una mayor productividad de mejillón. Estos resultados se pueden utilizar como guía para los agricultores durante un evento de cambio climático
Aquaculture Asia, vol. 12, no. 2, pp.1-50, April-June 2007
No full textAquaculture Asia is a magazine for farmers and aquaculture-related service industries. Articles cover all aspects of aquaculture and the related processing, marketing, economic, environmental and social issues that surround the industry, with regular sections on sustainable aquaculture, marine finfish aquaculture, aquatic animal health, research and farming techniques and the NACA Newsletter. Emphasis is placed on the practical outcomes of research that are of direct benefit to the industry, in particular to small-scale farmers. Articles in this issue include:
Towards sustainability of black tiger shrimp Penaeus monodon farming in Sri Lanka, by D.E.M. Weerakoon.
An economic analysis of stock enhancement of Persian sturgeon Acipenser persicus in Iran, by Hassan Salehi.
Aquaculture and environmental sustainability in Thailand: Food or financial security? By Jamie Stewart and Ram C. Bhujel.
Cage fish culture - successful income generation in manmade reservoir Kulekhani, Markhu, Nepal, by Ash Kumar Rai and Suresh Kumar Wagle.
Diversification of rice farming alleviates poverty in a Bangladesh village, by Peter Edwards.
Aquaculture of sea-pineapple, Halocynthia roretzi in Japan, by TTT. Nguyen, N. Taniguchi, M. Nakajima, U. Na-Nakorn, N. Sukumasavin, K. Yamamoto.
Development of green mussel cultivation in Thailand: Sriracha Bay, Chonburi Province, by Suriyan Tunkijjanukij and Alongot Intarachart.
Selective breeding for growth and fillet yield of river catfish Pangasianodon hypophthalmus in the Mekong Delta, Vietnam, by Nguyen Van Sang, Nguyen Van Hao, Dinh Hung, Pham Dinh Khoi, Bui Thi Lien Ha, Vu Hai Dinh, Nguyen Dien.
Fish for life: Producing high quality fish seed in rural areas of Asia, by David C. Little, Benoy K. Barman and Corinne Critchlow-Watton.
Utilisation of local feed ingredients in tiger grouper grow out moist diets, by Usman, Rachmansyah, Neltje N. Palinggi and Taufi k Ahmad.
Optimal nutrition for marine fish, by Arjen Roem.
SEAFDEC tests its feed formulations for marine fishes.
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