Evaluation of Water Quality Parameters, Growth and Proximate Composition of Juvenile Crab, Portunus pelagicus Cultured in RAS and Non RAS System

Abstract

Juvenile blue swimming crab, Portunus pelagicus were reared over 31 days in two different systems namely recirculating aquaculture system (RAS) and conventional aquaculture system (CAS) to evaluate the water quality parameters, growth, and its body composition. The juvenile crab, weighing of 0.95 ± 0.18 g and stocking was at 40 crabs m -2 and fed twice per day with a commercial shrimp pellet. During the experimental time, significantly (P <0.05) increment in dissolved oxygen (DO) (6.42 ± 0.13), low level of ammonia-nitrogen (0.04 ± 0.10) and nitrite-nitrogen (0.04 ± 0.10) were recorded in RAS than conventional aquaculture system (CAS) (DO: 5.99 ± 0.24;. The carapace width, weight gain and specific growth rate (SGR) were significantly (P <0.05) higher in RAS. Protein content (22.65 ± 0.11%) in crab also were significantly (P <0.05) higher in RAS compared with crab protein (21.41 ± 0.12%) cultured in CAS. Although the survival rate was slightly higher in the juveniles reared at CAS, however it was not significantly different comparing with the individuals reared at RAS. The results strongly suggested that the use of RAS may improve the growth performance and maintain the better water quality for the crabs in captivity. ABSTRAKKetam juvenil renang biru, Portunus pelagicus telah dipelihara selama 31 hari dalam dua sistem berbeza iaitu sistem akuakultur udara berulang (RAS) dan sistem akuakultur konvensional (CAS) untuk menilai parameter kualiti air, tumbesaran dan komposisi badan. Ketam juvenil seberat 0.95 ± 0.18 g dan penstokan adalah pada 40 ketam m -2 dan diberi makan dua kali sehari dengan pelet udang komersial. Semasa masa uji kaji percubaan, peningkatan (P < 0.05) dengan ketara oksigen terlarut (DO) (6.42 ± 0.13), tahap rendah ammonia-nitrogen (0.04 ± 0.10) dan nitrit-nitrogen (0.02 ± 0.07) direkodkan dalam RAS daripada konvensional sistem akuakultur (CAS) (DO: 5.99 ± 0.24;. Lebar karapas, pertambahan berat dan kadar pertumbuhan khusus (SGR) adalah ketara (P < 0.05) lebih tinggi dalam RAS. Kandungan protein (22.65 ± 0.11%) pada ketam juga adalah ketara (P < 0.05) lebih tinggi pada RAS berbanding dengan protein ketam (21.41 ± 0.12%) yang dikultur dalam CAS. Walaupun kadar kemandirian adalah lebih tinggi dalam juvenil yang dipelihara dalam CAS, walau bagaimanapun, ia tidak berbeza dengan ketara berbanding dengan individu yang dipelihara dalam RAS. Keputusan menyarankan bahawa penggunaan RAS boleh meningkatkan prestasi tumbesaran dan mengekalkan kualiti air yang lebih baik untuk ketam dalam kurungan. Kata kunci: Kemandirian; pertumbuhan; Portunus pelagicus; sistem akuakultur konvensional (CAS); sistem akuakultur udara berulang (RAS)

A review of influencing factors on a recirculating aquaculture system: Environmental conditions, feeding strategies, and disinfection methods

“…Furthermore, the proportion of operational taxonomic units of nitrifying bacteria in the bioreactor decreases significantly when the DO content decreases, especially the growth of heterotrophic nitrifying bacteria that is severely inhibited (Wei, Bi, et al, 2019), while the increase in the DO content (above 5 mg/L) is beneficial to the removal of ammonia, nitrate, and total nitrogen (Luo et al, 2014; Wei, Bi, et al, 2019). Kohinoor et al (2019) compared the growth performance of crabs, Portunus pelagicus , in RAS and non‐RAS systems, and the results showed that the crabs had a higher growth rate in RAS aquaculture ponds because of higher DO and lower ammonia and nitrite content. Meanwhile, the DO content should not be too high: excessive DO at a long time will lead to fish bubble disease whose symptoms include dyspnea, bulging eyes, anemia, and even death, especially causing severe harm to eggs and young fish (Wei, Jiao, et al, 2019).…”

The Composition of Portunus pelagicus on the Fishing Ground Area of Danasari Waters, Pemalang Regency

“…The pressure on blue swimming crab resources must be resolved, considering the dependence on natural stocks in the wild. Kohinoor et al (2019) showed that the survival rate for crab hatcheries was still shallow, with a proportion of only 40.10%. The efforts to manage fishing activities are an alternative that is usually applied by the local government, such as regulations on minimum carapace width, prohibition on catching female swimming crabs, and recommendations for using environmentally friendly fishing gear (Ernawati et al, 2015).…”