Effect of Different Salinities Gradient on Fatty Acid Composition, Growth, Survival and Reproductive Performance of Moina macrocopa (Straus 1820) (Crustacea, Cladocera)

Abstract

Salinity is a known factor which shapes population dynamics and community structure through direct and indirect effects towards aquatic ecosystems. The responses of Moina macrocopa (Cladocera) collected from Setiu Wetland lagoon (Terengganu) were evaluated through manipulative laboratory experiments to understand the ability of M. macrocopa to tolerate under high salinity stress. Specifically, the fatty acid composition, growth, survival and reproduction of this cladocerans species were examined. Sodium chloride (NaCl) were used in the treatments water with the concentration 0, 4, 6, 8, 12, and 15psu. Fatty acid levels were determined using Gas Chromatography and Mass Spectrophotometry (GC-MS). Results clearly indicate that normal conditions give the highest content of fatty acid, especially the polyunsaturated fatty acid content like EPA (eicosapentaenoic acid), ALA (alpha-linoleic acid), ARA (arachidonic acid) and DHA (docosahexaenoic acid). Furthermore, M. macrocopa survival also was best at 0psu, with percentage reached 98%, whereas the opposite occurred at 15psu, with approximately 9% of viable animals survived. On other aspects, M. macrocopa also showed the highest reproduction rate at 0psu (e.g. average initial age of reproduction, 4.33±0.58 days) compared with other salinities level. Interestingly, the difference in terms of growth at different salinities was unapparent, an unexpected outcome when adverse effects such as osmoregulation pressure on the organism are considered. Based on the results, we conclude that M. macrocopa can only tolerate salinity below 8psu and, is unable to withstand stressful environmental condition engendered with salinities above 8psu.

Thành phần loài và mật độ giáp xác râu ngành (Cladocera) và giáp xác chân chèo (Copepoda) trong ao nuôi tôm nước lợ thâm canh

“…Ngoài ra, Cladocera là nhóm quan trọng trong quần xã ĐVPS với hầu hết các loài phân bố trong môi trường nước ngọt ở độ mặn dưới 1‰ (Ghazy et al, 2009). Tốc độ tăng trưởng của M. macrocopa tăng lên trong điều kiện môi trường nước có độ mặn 0-6%, nhưng khi độ mặn tăng từ 8‰ đến 15‰ thì tốc độ tăng trưởng của chúng giảm thấp hơn (Rasdi et al, 2019).…”

A review on the improvement of cladocera (Moina) nutrition as live food for aquaculture: using valuable plankton fisheries resources

“…Moina species may also be considered a promising species for feeding fish larvae and fingerlings as they have a short lifespan, abundant energy storage, small size, and short embryonic stage (Sipauba-Tavares et al, 2014;Samuel, 2014). Moina macroocopa is a cladoceran mostly found in water bodies and plays a role in food chains in the aquatic environment (Iannacone and Alvarino, 2000;Vignatti et al, 2013) and, has economic importance arising from its use in aquaculture as live food for fish larval stages (Vignatti et al, 2013;Rasdi et al, 2019). Tawaratmanikul (1988) reported that Clarius batrachus, Ompok bimaculatus, Lates calcarifer and Channa striatus fish larvae show improved growth and survival for cladorans as live feed (Amornsakun et al, 2001;Budhin et al, 2016).…”