Impact of COVID-19 on aquaculture sector in Malaysia: Findings from the first national survey

Abstract Malaysian aquaculture sector consists of 391,000 t of cultivated organisms produced per year with an economic value for over USD 700 million as estimated in 2019. The COVID-19 pandemic caused a large global human pandemic and it is currently ongoing, affecting profoundly Malaysian aquaculture, which is vital for seafood provision and security assurance. Thus, to increase our understanding about how the pandemic affects aquaculture sectors is crucial to design possible management measures both at local and national level. To do it, we designed a survey, starting in May 2020, consisting of 25 online questions to collect information about the impact of COVID-19 on the aquaculture sectors in Malaysia. A total of 105 respondents (2625 answered questions) was captured within the Movement Control Order (MCO) period and later extended to the Conditional MCO (CMCO). Almost 90 % of respondents was unanimous in answering that, and COVID-19 had a heavy effect on aquaculture-related activities in Malaysia; 80 % of them indicated the market demand and logistic bottlenecks (72 %) as major constraints on their aquaculture activities. While the major option to solve aquaculture COVID-19 related issues was the use of online market or digital platforms (76 %), a large fraction of respondents requested for specific assistance to support aquaculture activities (e.g. financial support). Most respondents (93 %) was aware about the necessity of the Standard Operation Procedure (SOP) provided by the relevant agencies during the MCO / CMCO. Present data are crucial to develop policy measures both at national and international level to support seafood sectors under pandemic

Low water pH depressed growth and early development of giant freshwater prawn Macrobrachium rosenbergii larvae

Macrobrachium rosenbergii is one of the shellfish species with high aquaculture value due to its increasing market demand. However, the comparatively low production volume compared to demand coupled with the rapid decline of the natural environment, consequently, drives the potential depletion of the wild population. The decrease in water pH related to anthropogenic pollution is one of the most critical factors affecting the early life performances of M. rosenbergii. Therefore, this study was designed to examine the effect of low water pH on feeding, growth and development of M. rosenbergii early life stages. Experimental water pH was set as neutral (7.7 ± 0.4); mild-acidic (6.4 ± 0.5) and acidic (5.4 ± 0.2) with triplication at a stocking density of 2 larvae/L for 30 days. As expected, M. rosenbergii larvae were highly sensitive to acidic pH with no larvae survived beyond 48 h of exposure. Feeding, survival and growth of larvae were adversely affected by mild-acidic pH exposure as compared to neutral pH. Larvae exposed to mild-acidic water pH experienced a prolonged larval period and only metamorphosed to the post-larval stage at day-30. Whilst under neutral water pH, larval that metamorphosed to post-larval was first observed on day-23. The negative impact of decreased pH, even in mild-acidic pH exposure, on the feeding, survival, growth and development of M. rosenbergii larvae highlights the urgency of periodic pH monitoring during M. rosenbergii larviculture

Impact of face mask microplastics pollution on the aquatic environment and aquaculture organisms

Microplastic pollution in our environment, especially water bodies is an emerging threat to food security and human health. Inevitably, the outbreak of Covid-19 has necessitated the constant use of face masks made from polymers such as polypropylene, polyurethane, polyacrylonitrile, polystyrene, polycarbonate, polyethylene, or polyester which eventually will disintegrate into microplastic particles. They can be broken down into microplastics by the weathering action of UV radiation from the sun, heat, or ocean wave-current and precipitate in natural environments. The global adoption of face masks as a preventive measure to curb the spread of Covid-19 has made the safe management of wastes from it cumbersome. Microplastics gain access into aquaculture facilities through water sources and food including planktons. The negative impacts of microplastics on aquaculture cannot be overemphasized. The impacts includes low growth rates of animals, hindered reproductive functions, neurotoxicity, low feeding habit, oxidative stress, reduced metabolic rate, and increased mortality rate among aquatic organisms. With these, there is every tendency of microplastic pollution to negatively impact fish production through aquaculture if the menace is not curbed. It is therefore recommended that biodegradable materials rather than plastics to be considered in the production of face mask while recycle of already produced ones should be encouraged to reduce waste

Female tilapia, Oreochromis sp. mobilised energy differently for growth and reproduction according to living environment

Abstract This study was conducted to investigate the energy mobilisation preference and ionoregulation pattern of female tilapia, Oreochromis sp. living in different environments. Three different treatments of tilapia as physiology compromising model were compared; tilapia cultured in recirculating aquaculture system (RAS as Treatment I—RAS), tilapia cultured in open water cage (Treatment II—Cage) and tilapia transferred from cage and cultured in RAS (Treatment III—Compensation). Results revealed that tilapia from Treatment I and III mobilised lipid to support gonadogenesis, whilst Treatment II tilapia mobilised glycogen as primary energy for daily exercise activity and reserved protein for growth. The gills and kidney Na+/K+ ATPase (NKA) activities remained relatively stable to maintain homeostasis with a stable Na+ and K+ levels. As a remark, this study revealed that tilapia strategized their energy mobilisation preference in accessing glycogen as an easy energy to support exercise metabolism and protein somatogenesis in cage culture condition, while tilapia cultured in RAS mobilised lipid for gonadagenesis purposes