Aquaculture Production and Value Chains in the COVID-19 Pandemic.

PURPOSE OF REVIEW: The purpose of this review is to summarize the impacts of the coronavirus disease 2019 (COVID-19) pandemic on aquaculture input supply, production, distribution, and consumption. RECENT FINDINGS: The COVID-19 pandemic-related lockdowns, social distancing, supply chain disruptions, and transport restrictions affect seafood production, distribution, marketing, and consumption. Recommendations are suggested to overcome these challenges. The COVID-19 has led to disruption of aquaculture practices worldwide. The pandemic has adversely affected the aquaculture input supply of fish stocking and feeding, which, in turn, has impacted aquaculture production. Moreover, the COVID-19 crisis has had adverse effects on value addition to aquaculture products, through the restrictions of seafood marketing and exporting. Aquatic food production is vulnerable to the effects of COVID-19 outbreak; hence, adaptation strategies must be developed to cope with the challenges. There is an urgent need for collaboration among key stakeholders to rebuild the supply chain of inputs and fish marketing for sustainable aquaculture practices. International agencies, donors, government and non-governmental organizations, researchers, and policymakers need to develop policies to support aquaculture production and supply chains.

Trends and developments in thermal tolerance: A scientometric research study.

Climate action was among one of the main targets for the United Nation Sustainable Development Goals (i.e. UN SDG: 13), which is to "take urgent action to combat climate change and its impacts". The United Nations Framework Convention on Climate Change (UNFCCC) is also concurred to improve climate change's mitigation and adaptation strategies along with the SDG's goals. Thermal tolerance has been proposed as one of the possible adaptation strategies for animals affected by anthropogenic effects and excess heat from climate change. However, no scientometrics analysis of thermal tolerance research has been conducted to date. As a result, the goal of this study was to gather information from the literature to determine the current state of thermal tolerance, development trends, and current research. Researchers will be able to better understand the trends and development of the thematic research area of thermal tolerance by using scientometric analysis to generate data on thermal tolerance. For frequency, co-occurrence, co-citation, clustering, and burst analysis, CiteSpace software was used. The scientometric review of thermal tolerance studies from 1970 to 2021 (5243 studies) reveals significant increases in the size of the literature, the frequency of citations, and the hotspots investigated. Susan Lindquist and the Journal of Thermal Biology are the most influential authors and journals, respectively. The most common clusters related to the thematic area of thermal tolerance are oxygen consumption and heat shock protein, with climate change and temperature being one of the most popular keywords. We concluded that, along with the thriving field and climate change issues, thermal tolerance is becoming one of the future research interests. In addition, knowing the current trends and developments of thermal tolerance in aquatic species is important for various stakeholders.

Use of Pelleted Diets in Commercially Farmed Decapods during Juvenile Stages: A Review.

The increasing market demand for decapods has led to a considerable interest in cultivating decapod species at a larger scale. Following the development of hatchery technologies, most research has focused on the development of formulated feeds for commercially farmed decapods once they enter the juvenile stages. The use of formulated feed for decapods at a commercial scale is still in the early stages. This is probably because of the unique feeding behavior that decapods possess: being robust, slow feeders and bottom dwellers, their feeding preferences change during the transition from pelagic larvae to benthic juveniles as their digestive systems develop and become more complex. The current practice of decapod aquaculture involves the provision of juveniles with food such as natural diet, live feed, and formulated feed. Knowledge of nutrient requirements enables diets to be better formulated. By manipulating the levels of proteins and lipids, a formulated feed can be expected to lead to optimal growth in decapods. At the same time, the pellet's physical characteristics are important factors to be considered upon formulating commercially farmed decapod feeds, considering the unique feeding behavior of the decapod. However, most published studies on decapod nutrition lack data on the physical characteristics of the feed types. Thus, it is difficult to establish a standard feed formulation that focuses on the physical pellet properties. Moreover, careful consideration must be given to the feeding behavior of species, as decapods are known as bottom feeders and are robust in terms of handling feed. Information on the pellet forms, diet composition, and unique feeding behaviors in commercially farmed decapods is gathered to suggest potential better formulated diets that can optimize growth and reproduction. Thus, the purpose of this review is to summarize the information that has been published to date and to come up with suggestions on ways to improve the feed formulation in decapods that comply with their feeding behavior and nutrient requirements. Further research is needed to explore the potential of the pelleted feed at the adult stage so the decapod can take full advantage of the nutrients present in the pellets.

Dataset on body weight, carapace width increment and growth band count of mud crabs, Scylla olivacea.

The present paper contains two datasets; i) the growth band count (GBC) of mud crab, Scylla olivacea collected from Setiu Wetlands, Terengganu coastal water, East coast of Peninsular Malaysia and ii) the increment sizes of body weight (BW) and carapace width (CW) of immature S. olivace after molting. The datasets presented here were associated with the research articles entitled i) "Study on carapace width growth band counts relationship of orange mud crab, S. olivacea (Herbst, 1796) from Terengganu Coastal Waters, Malaysia" (Hasyima-Ismail et al. 2017) [1] and ii) "Relationship between the carapace width and body weight increments and the confirmation of Stage 1 ovary after the molting of immature orange mud crabs, S. olivacea (Herbst, 1796), in captivity" (Amin-Safwan et al. 2019-2020) [2], and provided here as raw data of Supplementary materials. Raw datasets for GBC in the wild were generated by examination of the thin cross sectioning process of the gastric mill of S. olivacea. The GBC were measured for each individual crab wherein band counts ranged from 1 to 3. The analysis provides evidence that the GBC of the crabs can be determined through both mesocardiac and zygocardiac ossicles. This data is of importance to researchers for estimation of stock assessment and improvement of fisheries management to further improve policy. For the BW-CW increment data, a total of 135 immature crabs were sampled from Setiu Wetlands, Terengganu, Malaysia, and were introduced to limb autotomy technique in order to induced molt. Crabs were reared until successful molting and immediately prior to hardened shell, before final measurement of body weight and carapace width determination. Recorded data was analyzed by calculating the increment sizes, along with correlation and regression analysis between body weight and carapace width of mud crabs.

Data on the molting duration and time of hardening of instar crab at different culture temperatures.

This data article includes raw and analyze data for molting duration and time of hardening of blue swimming crab, Portunus pelagicus instar at three different temperatures of 24 °C, 28 °C, and 32 °C. Two sets of experimental data are included: first, the recorded on time-lapse video of duration of successful molted crabs (from emergence of swimming legs to chelae); and second, the time interval of shell hardening up to before molting occurred. Shell hardening were calculated in 1 h interval with a unit of x hour molting crab-1, meanwhile the molting duration of the crabs were calculated in x second molting crab-1. Video files were then analyzed using the latest version of Solomon Coder software developed by A. Peter. Relationship between culture temperature and the time of molting and carapace hardening are also included in this article. The dataset is made publicly available to enable critical or extended analyzes.

Behavioural data on instar crab movement at different thermal acclimation.

This article investigated how crabs responded to different culture temperatures especially dislocation before molting using a combination of large recording files and computer software. In this novel approach of video recording portunid crab behavioral data, crab culture was recorded at five different acclimation temperatures of 20, 24, 28, 32 and 36 °C. Crabs were reared until the instar stage before being acclimatized for video recording. Large video files (MPEG-TS) were then analyzed using the latest version of Solomon Coder software developed by A. Peter and programmed with Embarcadero® Delphi® XE [1]. Recorded data was analyzed by calculating and marking movements of crabs using the time sequence tool. Additionally, a total movement was counted 30 min before crabs molted from instar stage 8 to instar stage 9. Part of the data is associated with the research article "Thermal tolerance and locomotor activity of blue swimmer crab Portunus pelagicus instar reared at different temperatures" (Azra et al., 2018) [2] and provided here as raw data of Supplementary materials.

Thermal tolerance and locomotor activity of blue swimmer crab Portunus pelagicus instar reared at different temperatures.

Owing to its potential market value, the blue swimmer crab Portunus pelagicus is of great economic importance. The temperature of water significantly affects the physiological function and production efficiency of these crabs. The aim of the present study was therefore to examine the critical thermal minimum (CTMin), critical thermal maximum (CTMax), acclimation response ratio (ARR), escaping temperature (Tesc), and locomotor behavior of P. pelagicus instars at 20 °C, 24 °C, 28 °C, 32 °C, and 36 °C. The CTMax ranged from 39.05 °C to 44.38 °C, while the CTMin ranged from 13.05 °C to 19.30 °C, and both increased directly with temperature. The ARR ranged from 0.25 to 0.51. The movement of crabs (walking before molting) correlated positively with the acclimation temperature. These results indicate that the parameters evaluated varied with temperature. Furthermore, the high CTMax indicates the potential of this species to adapt to a wide range of temperatures. In addition, the implications of these findings for portunid crabs behavior and distribution in their natural habitat are also discussed.

A review of maturation diets for mud crab genus Scylla broodstock: Present research, problems and future perspective.

Study of broodstock maturation diets is important in order to increase the quality of berried females, which indirectly improve the larval quantity in the hatchery production of cultured species. This paper reviewed the studies on the maturation diets for mud crab broodstock, genus Scylla and compared independently to identify their effect on reproductive performance and larval quality. The broodstock is usually caught from the wild and held in the spawning or maturation tank for further use of hatchery seed production. Mud crab broodstock was fed either natural diet, artificial diet or mixed diet. Trash fishes were commonly used as a natural feed for mud crab broodstock; meanwhile artificial diets are from formulated fish meal and various kinds of feed. The results indicated that mud crab broodstock has a high dietary requirement for lipids, fatty acids and protein which are to be used during the maturation and breeding processes. However, the natural diet produce better larval quality compared to the artificial diet. The mixed diet is the better diet which resulted in better reproductive performances such as growth, survival, fecundity and maturation processes. This review also discusses the problems in the previous studies for the potential future research to develop very high quality and cost-effective formulated diet for the enhancement of broodstock and seed production technology. Information from this review can be useful in developing a better quality of crustacean broodstock's diet for commercial hatchery production.