Marine Aquaculture Production Research Articles

Mapping the Global Carbon Emissions of Marine Sectors.

The ocean serves as a vital ecosystem for sustaining life on earth and ensuring human well-being. Presently, there is a significant surge in global demand for various ocean-based economic activities, including fishing, shipping, offshore wind energy production, maritime tourism, and so on. However, this growth has also resulted in an increase in emissions from marine sectors, which have not been thoroughly evaluated or analyzed. It is therefore necessary to conduct comprehensive evaluations of the current emissions, covering marine sectors. To address this need, through this Perspective, we have globally analyzed and discussed carbon emissions linked to maritime transportation, marine capture fisheries, marine aquaculture, offshore wind, ocean renewables, and crude oil production. Additionally, we explored country-specific scales for these emissions and discussed points for future research to address the existing gaps. By gaining a better understanding of emissions over the oceans, policymakers could prioritize policy measures for achieving emission reduction goals and promote sustainable ocean development.

A Thorough Insight into the Biofilm Properties of Potential Fish Pathogen Tenacibaculum discolor Strain FMCC B487

Tenacibaculum discolor develops biofilm in marine aquaculture production tanks and is identified as one of the causative agents of tenacibaculosis, a bacterial disease that causes significant losses in marine aquaculture production. In this study, the biofilm characteristics of T. discolor strain FMCC B487 were evaluated. Cell growth and biofilm formation and development were studied in miniaturized assays to assess the effect of different levels of environmental factors temperature and salinity, as well as the presence of monosaccharides potentially found in aquaculture hatcheries. The ability of the strain to grow and develop strong biofilms in ambient to high temperatures and at salinities above 20 g/L was shown. Mannose was the monosaccharide with the most prominent impact on the T. discolor strain FMCC B487 biofilm. The composition of planktonic cell extract, biofilm extracts, and extracellular polymeric substances (EPS) produced by T. discolor strain FMCC B487 were investigated by means of colorimetric and fluorometric assays as well as analyses by electrophoresis, gas chromatography, and high-performance size-exclusion chromatography coupled with a multiangle light scattering detector, revealing the dominance of proteins and lipids and the absence of high-molecular-weight polysaccharides. This information may serve as a basis for considering anti-biofilm strategies against the pathogen T. discolor.

Antioxidant activity of crude fucoidan extract from brown seaweeds (Phaeophyceae), Sargassum sp. and Turbinaria sp.

Seaweed is one of the highly commercial aquatic commodities, accounting for 51.3% of total marine and coastal aquaculture production. As much as 99.5% of seaweed production is concentrated in Asia, especially in East and Southeast Asian countries, one of which is Indonesia. The wide diversity of seaweeds has not been fully optimizing their potential to provide maximum economic benefits. This study aimed to determine the characteristics of crude extracts of fucoidan using two different solvents and to analyze the antioxidant activity of crude extracts of fucoidan using different solvents. The research method included the preparation of raw materials, extraction with distilled water and 2% CaCl2 at 85 °C for 4 h, followed by quality analyses. Total sugar using the phenol-sulphate method obtained higher results in distilled water (67.88%). The total sulphate analysis showed higher results with 2% CaCl2 (19.60%). The total phenol analysis yielded higher results with 2% CaCl2 (978.20%). The antioxidant activity of the crude fucoidan were 312.01 ppm (distilled water), 193.52 ppm (distilled water), 54.653 μg/mL ascorbic acid/g extract (CaCl2 2%, 128.38 mol Fe2+/g (CaCl2 2%).

The role of marine aquaculture in contributing to the diversity and stability of U.S. seafood production

Seafood systems are likely to face increasing environmental, economic, and political stressors, leading to disruptions to marine ecosystems and to the communities that depend on harvest of marine resources. Drawing from portfolio theory, we suggest that a more diverse industry might be more stable and resilient in the face of these stressors; and one important source of diversification could be from increasing and broadening marine aquaculture production. This is one argument for encouraging development of marine aquaculture within the United States, where the industry currently accounts for < 10% of domestic seafood value. Using regional production data, we explore the evidence that marine aquaculture development helps diversify the seafood system in the United States and make it less vulnerable to outside stressors, while also highlighting data limitations that hinder a more rigorous analysis. Our results suggest that a seafood strategy that focuses on diversity – both within marine aquaculture and by increasing the sector’s contribution to U.S. seafood production – may help achieve a more stable and resilient national seafood industry.

Hydrodynamic coefficients of mussel dropper lines derived from large-scale experiments and structural dynamics

The expansion of marine aquaculture production is driven by a high market demand for marine proteins and a stagnation of wild catch of fish. Bivalve farming, i.e., the cultivation of oysters, mussels and scallops, is an important part of the ongoing market dynamics and production expansion. As marine spatial planning is considering various use purposes, available space for near-shore aquaculture is already becoming scarce; this has fueled research and development initiatives to enable production installations further offshore. The highly energetic conditions at more exposed offshore marine sites lead to increased loads on aquaculture systems and their components and it is still not sufficiently understood how the load transfer from oceanic environmental conditions onto shellfish-encrusted surfaces attached to elastic ropes may be appropriately quantified. This study data gathered large-scale data sets in a wave tank facility, which are used to validate a novel, numerical model, building on the dynamics of rope structures which allows for the determination of the hydrodynamic loads transferred to the dropper lines. The forces and hydrodynamic parameters are measured and numerically analyzed. Based on the results, drag and inertia coefficients are determined. A drag coefficient of CD=1.1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$C_\ extrm{D} = 1.1$$\\end{document} and an inertia coefficient of CM=1.7\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$C_\ extrm{M} = 1.7$$\\end{document} are recommended to model shellfish-encrusted dropper lines exposed to oscillatory flows with KC =\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$=$$\\end{document} 40–90. The numerical model for the determination of wave-induced forces on mussel dropper lines is developed and validated using the experimental data. It employs a modified Morison equation, which takes into account the displacement of the mussel dropper line. The influence of varying aquaculture-related parameters is discussed by applying the numerical model. Based on the gathered insights, recommendations can be given from an engineering point of view concerning the optimal placement of mussel aquaculture within the water column.

The Present Situation of the Fisheries Sector in Iraq: A Critical Review

In this review, the status of fisheries in Iraq is described. Iraq has two main water resources, the Tigris and Euphrates Rivers, forming a water area of approximately 700,000 hectares. Surface waters are distributed as natural lakes (39%), dam lakes (13.3%), and rivers and their tributaries (3.7%). On the other hand, marshes constitute 44% of the water sources in Iraq. The Iraqi government began recording fish production from wild and aquaculture in 1986. Total fish production from freshwaters in Iraq in 1991 and 1998 were 18,800 and 30,000 tons, respectively. In 2020, the total fish production in Iraq reached to 241,848 tons (Anonymous, 2022a). The bulk of fish production belonged to carps followed by barbs (genus Barbus) and trouts. With respect to capture fishing in Iraq, a variety of trawl nets (single-bag and multi-bag) and gillnets have commonly been used. The 1970s and 1980s were characterized by low consumption of fish meat (i.e., 4.3 kg in 1979), but it has gradually increased over the last years and has reached a remarkable 10 kg per capita in 2020. In this review, freshwater and marine fish species, aquaculture production and wild catch, institutions and centers specialized in researching and developing fisheries, fish meat consumption, problems of the fishing industry and potential solutions to develop the fishing industry in Iraq are outlined. This is the first study on the present status of fisheries in Iraq.

Reciprocal hybrids of Atlantic salmon (Salmo salar) x brown trout (S. trutta) confirm a heterotic response to experimentally induced amoebic gill disease (AGD)

Amoebic gill disease (AGD) affects global marine aquaculture production of Atlantic salmon, requiring costly reiterative treatment and negatively impacting fish performance and welfare. Although there has been gradual and ongoing progress in genetic selection to improve host resistance to the causative agent (Neoparamoeba perurans) there has been little focus on the response of interspecific hybrids to AGD challenge. Previous research has demonstrated that Atlantic salmon x brown trout hybrids had reduced requirement for freshwater bathing (based on gross gill signs) during chronic natural AGD exposure, yet there has been no histological or molecular evidence confirming differential host response or parasite abundance. In this study we exposed Atlantic salmon (SS), brown trout (TT) and their reciprocal interspecific hybrids (TS and ST) to a single laboratory challenge (∼700 amoebae.l−1 for 18 days) and compared the resultant infection and disease signs characteristic of AGD. Gill score was significantly higher in SS than in TT and hybrids. Copy number quantification of amoebae on gills was higher in salmon than in hybrids or trout but did not differ between hybrids and trout. Gill histopathology confirmed both an increased amoebae abundance and higher expression of host tissue reaction in SS with significantly higher percentages of lesions harboring hyperplastic lesions. Mid-parent and best-parent heterosis of resistance to N. perurans and host response (gill lesions) was confirmed but did not differ between hybrid crosses. Although limited to a single laboratory infection event, our results support previously reported observations (from natural infection/reinfection) of reduced AGD signs in trout and interspecies hybrids. We conclude that interspecies hybrids have potential to improve our understanding of salmonid resistance to amoebic branchitis and support future gene-based research toward fish disease management.

Acute hydrogen sulfide exposure in post-smolt Atlantic salmon (Salmo salar): Critical levels and recovery

Despite the importance of Atlantic salmon in marine aquaculture production systems, remarkably little is known about the effects of hydrogen sulfide (H2S) on the physiology of the species. In recent years, mass mortalities of Atlantic salmon have been reported in recirculating aquaculture systems (RAS) due to acute H2S exposure. This highlights the importance of obtaining a better understanding of tolerance thresholds and metabolic responses to this toxic gas. The toxicity of H2S is exerted at the level of the mitochondria, where impairment of the enzyme cytochrome c oxidase inhibits cellular respiration. Because H2S depresses oxygen uptake (MO2), intermittent flow-through respirometry, a common method for assessing the metabolic response to various stressors in fishes, is a suitable method to determine concentration thresholds for when H2S affects the metabolism of Atlantic salmon. During exposure trials, 3 size groups (range ⁓100-500 g) of fish were acclimated to control conditions to obtain baseline measurements, whereafter they were exposed to progressively increasing H2S concentrations (0.53 ± 0.14 μM h−1) until MO2 decreased below the standard metabolic rate or loss of equilibrium occurred, which we considered to be the critical H2S concentration (H2Scrit). Fish were then allowed to recover in H2S free water to determine the excess oxygen consumption (EOC) following H2S exposure. The results show that Atlantic salmon have a lower tolerance to H2S than previously estimated, with a mean H2Scrit of 1.78 ± 0.39 μM H2S, which was independent of size. During recovery, the estimated EOC greatly exceeded the accumulated oxygen deficit (DO2) in all groups, and the small salmon had a significantly larger EOC. While the magnitude of the EOC was greater for small salmon, it did not differ in duration (recovery time) among the different sizes of fish. The larger EOC showed that H2S exposure had a greater effect on the recovery phase of the small salmon, and exposure to H2S may leave the fish more vulnerable to other stressors post-exposure. This study provides specific values that underline the sensitivity of Atlantic salmon to acute H2S exposure and emphasizes the importance of the aquaculture industry to implement mitigating strategies for the occurrence of H2S at production facilities.

The Application and Research of New Digital Technology in Marine Aquaculture

Marine aquaculture has become an important strategy to enable the ecological and sustainable development of fishery due to the decreasing natural fishery resources. To solve farming pain points, improve farming efficiency and modernize fisheries, new digital technologies, such as the Internet of Things, big data, cloud computing, artificial intelligence and blockchain, are increasingly being widely applied in aquaculture. This paper introduces the interrelationship of new digital technologies and the framework of their application in marine aquaculture. The results of the application of each new digital technology in marine aquaculture are highlighted, and the advantages or problems of each new digital technology in marine aquaculture are pointed out. Further, the application of new digital technologies in deep-sea aquaculture facilities is enumerated. Finally, the main problems faced by new digital technologies in the process of marine aquaculture production and the future development trend are sorted out and summarized to provide scientific reference for promoting the wide application of new digital technology in marine aquaculture.

Ecological carrying capacity in mariculture: Consideration and application in geographic strategies and policy

Governance and management strategies for aquaculture development were examined for a select number of jurisdictions covering a range of marine aquaculture production to better understand the degree to which concepts of “Ecological Carrying Capacity” (ECC) are incorporated into management tools or permitting requirements for aquaculture development. Policies, regulations, and strategic plans were sought through professional knowledge and, at times, using web-based searches. Aquaculture ECC, defined here as, “the magnitude of aquaculture production that can be supported without leading to unacceptable changes in ecological process, species, populations, or communities in the environment,” was not strictly applied in any jurisdiction’s aquaculture policy documentation. A broadened search to consider the concept of aquaculture carrying capacity (CC) more generally was conducted. Of the ten nations examined, CC concepts could be found in policy documentation of several nations. The inclusion of CC concepts in policy and strategic planning can be used as part of a suite of management tools to promote sustainable aquaculture within FAO’s Ecological Approach to Aquaculture.

Planning and licensing for marine aquaculture.

Marine aquaculture has the potential to increase its contribution to the global food system and provide valuable ecosystem services, but appropriate planning, licensing and regulation systems must be in place to enable sustainable development. At present, approaches vary considerably throughout the world, and several national and regional investigations have highlighted the need for reforms if marine aquaculture is to fulfil its potential. This article aims to map and evaluate the challenges of planning and licensing for growth of sustainable marine aquaculture. Despite the range of species, production systems and circumstances, this study found a number of common themes in the literature; complicated and fragmented approaches to planning and licensing, property rights and the licence to operate, competition for space and marine spatial planning, emerging species and diversifying marine aquaculture production (seaweed production, Integrated Multi-Trophic Aquaculture [IMTA], nutrient and carbon offsetting with aquaculture, offshore aquaculture and co-location and multiuse platforms), and the need to address knowledge gaps and use of decision-support tools. Planning and licensing can be highly complicated, so the UK is used as a case study to show more detailed examples that highlight the range of challenges and uncertainty that industry, regulators and policymakers face across interacting jurisdictions. There are many complexities, but this study shows that many countries have undergone, or are undergoing, similar challenges, suggesting that lessons can be learned by sharing knowledge and experiences, even across different species and production systems, rather than having a more insular focus.

Assessment of greenhouse gases emissions and intensity from Chinese marine aquaculture in the past three decades

Marine aquaculture is increasingly gaining importance as a source of food with high nutritional value. However, the expansion of aquaculture could be responsible for water contamination that influences the environmental quality of coastal ecosystems, and emissions of greenhouse gases (GHG) that affect global climate. China is the world's largest producer of marine aquaculture protein, which demands robust studies to assess the corresponding GHG emissions and intensity. To fill in this knowledge gap, the current study quantifies and analyzes GHG emissions and intensity (emission intensity is defined as GHG emissions per unit of production) from Chinese marine aquaculture (marine aquaculture production) over the past 30 years (1991–2020). The production of marine aquaculture comes from the China Fisheries Statistical Yearbooks. And the GHG emissions and intensity were calculated based on five sectors (commercial feed, trash fish, N2O, CH4, and energy) by Emission-Factor Approach. The results suggest that, excluding shellfish and algae, GHG emissions of ten coastal provinces (excluding Shanghai, Hong Kong, Taiwan, and Macau) increased from 2 Mt (109 kg) CO2-eq in 1991 to 25 Mt CO2-eq in 2020. In contrast, GHG emission intensity decreased in the same period from 7.33 (t CO2-eq/t production) to 6.34 (t CO2-eq/t production), indicating a progressive mitigation in GHG emissions per unit of product, hence sustainably satisfying a growing demand for food. As a result, China's marine aquaculture seems to be paving a promising way towards the neutrality of GHG emissions. In most provinces, GHG is on the rise, and only in Tianjin is on the decline in recent years. For the emissions intensity, the values of more than half provinces showed the downtrends. In addition, by considering the ratio of shellfish and algae, Chinese marine aquaculture can improve the net zero goal for GHG emissions of the sector. Finally, results also reveal for the first time the changes in taxonomic composition and spatial GHG emissions and intensity, providing new understanding and scientific bases to elaborate consistent mitigation strategies for an expanding global marine aquaculture.

Seasonal energetic physiology in the ark shell Anadara kagoshimensis in response to rising temperature

Knowledge of physiological responses of important shellfish species to rising temperatures is crucial in assessing the impacts of climate change on marine aquaculture production. The physiological components of energy balance that support growth performance were measured seasonally at different exposure temperatures in the ark clams (Anadara kagoshimensis) cultured in the shallow muddy bottom sediment in Yeoja Bay, Korea. We tested the effects of winter minimum (3–8°C) and summer maximum (23–28°C) temperature elevations on individual physiological processes (ingestion, respiration, egestion, and excretion) and the combined energetic physiology (scope for growth [SFG] and net growth efficiency [K2] measures). The seasonal cycle of dry flesh tissue weight (DW) was also investigated from January 2016 to November 2018, to compare its variation at contrasting cold vs. warm regimes. The rates of physiological components were related to DW, generating significant allometric equations. The weight exponents of the equations for ingestion rate and respiration rate were low at the winter minimum compared with the remaining season temperatures, indicating a higher thermal sensitivity in larger individuals. The physiological rates that were re-calculated for individual components based on estimates of the slope and intercept of the equations increased with increasing temperature, revealing an incapability of thermal acclimation and a temperature effect at seasonally different endogenous conditions. The thermal sensitivity (Q10) of the ingestion rate and respiration rate was reversed between the winter minimum and the summer maximum temperature elevations, yielding negative SFG and K2 values at 3 and 28°C. Furthermore, the interannual difference in the seasonal cycle of clam DW displayed variations in the period of increment prior to spawning and the post-spawning loss/recovery in association with its energy balance status in the winter and summer temperature conditions. Overall, these results indicate that warming is projected to affect physiological performance and the seasonal DW cycle of clams in different manners between winter and summer: physiological benefits and advanced weight gain vs. heat stress and progressive weight loss, respectively. The mechanistic adjustment of the clam energy balance across thermal conditions seems to explain the recent advancement in its seasonal biological cycle, as well as the failure in spat collection and the mass summer mortality observed at this culturing site.

Thermal tolerance, safety margins and acclimation capacity assessments reveal the climate vulnerability of large yellow croaker aquaculture

With the ongoing climate change, marine aquaculture and other food production sectors will face new significant challenges in the next century. Despite the importance of these new challenges, understanding the dynamic thermal tolerance and thermal safety status of some major culture species remains scarce, including large yellow croaker (Larimichthys crocea), the most productive mariculture fish in China. Here, we conducted a relatively complete thermal biology assessment of cultured large yellow croaker using long-term acclimation experiments, critical thermal testing and the collected habitat sea surface temperature (SST) data. Changes in body size, oxidative stress and metabolic biomarkers during acclimation were also measured to evaluate the effects of prolonged thermal stress on performance. Results showed that the critical thermal limits of large yellow croaker acclimated at 11–30 °C ranged from 5.27 °C to 36.64 °C, and the total thermal tolerance zone was 444.74 °C2. Thermal limits increased as acclimation temperature rise, and the estimated acclimation response ratios ranged from 0.32 to 0.63, showing obvious thermal plasticity. The estimated post-acclimation thermal sensitivity values (0.80–1.28) for large yellow croaker acclimated at 11–30 °C were close to 1, and the heat- (5.78 °C) and cold-thermal safety margins (6.33 °C) were both high, showing sufficient thermal tolerance to cope with current observed highest SST and the predicted SST caused by climate change. However, performance results showed that long-term exposure to 30 °C would induce energy redistribution and tradeoffs between health/growth and heat tolerance, leading to significantly decreased body weight and increased superoxide dismutase activity in the gill. This result indicates a potential disadvantage of growing large yellow croaker in floating sea-cages, because the shallow culture depth, high density and limited moving spaces in this farming mode make the fish susceptible to fluctuations in SSTs, constrain their ability in behavioral thermoregulation, and increase the risks of hypoxia and disease infections. Thus, these tradeoffs may make the current floating sea-cage farming more vulnerable to elevated temperatures on production. Finally, since our recorded highest in situ SST and warming rate (in summer) have reached up to 30.1 °C and 1.2 °C/d, we propose that the large yellow croaker farms currently operating in the main producing area of China are already at the risk of summer heatwaves. In the future, more efforts should be made to the selection of heat-resilient strains or the exploration of alternative farming systems in large yellow croaker aquaculture industry to avoid or mitigate potential production decline.

Myxozoan Research Forum 2021 - the ‘MyxoMixer’: Advances, methods, and problems yet to be solved in myxozoan research

Myxozoans are morphologically reduced and genetically derived cnidarian parasites that have acquired annelids and bryozoans as their primary hosts, and vertebrates, predominantly fish, as their secondary hosts. Several myxozoans are known pathogens impacting freshwater and marine aquaculture production systems, with some species classified as emerging pathogens promoted by climate change processes. Despite the obvious need, there is currently no general legalized treatment or vaccine for myxozoans. Solutions are delayed due to quirks in the biological and molecular characteristics of myxozoans, and by the lack of tools and consensus in research approaches used to tackle the most economically impactful myxozoans.

CLUSTERING PRODUKSI PERIKANAN BUDIDAYA LAUT BERDASARKAN PROVINSI MENGGUNAKAN ALGORITMA K-MEANS

Indonesia is a large maritime country, and most of its territorial waters are larger than its land area. Due to the vastness of the oceans, the large number of large and small islands makes Indonesia a potential area for marine cultivation. In general, the existing data based on the Central Statistics Agency (BPS) of Marine Aquaculture Production for each province in Indonesia only applies to production data which only produces detailed data on total marine aquaculture production in tonnes per year, and takes a long time. To classify very large data, a method is needed that can use the K-Means algorithm to classify the highest, middle, and lowest opportunities in the field of marine aquaculture from 2004 to 2018. The results implemented in python consisted of 26 provinces in klaster 1 (C1), 3 provinces in klaster 2 (C2), and 5 provinces in klaster 3 (C3).

The Impact of Pollution on China Marine Fishery Culture: An Econometric Analysis of Heterogeneous Growth

The damage caused by pollution is not equal across individuals within a given population, due to the differences in pollution level and coping ability. Identifying the different impacts of environmental pollution on agricultural economic growth and the source of the pollution is of great reference significance for realizing the organic integration of ecological protection and relative poverty alleviation. This study takes marine fishery culture as an example, with the cultured products data of 53 coastal cities in China from 1994 to 2018 and empirically captures the heterogeneous effects of environmental pollution on mariculture growth by constructing a theoretical analysis framework of heterogeneity in pollution damage. Results show that the deepening of marine environmental pollution will reduce the growth rate of marine cultured output, emerging significant regional differences. Nevertheless, under the background of the complex environmental situation currently, further damages mainly derive from the difference in the ability to deal with environmental pollution rather than the difference in pollution degree. In terms of different wastewater sources, the impact of industrial wastewater discharge on marine aquaculture production is not very significant. In contrast, the adverse shocks of urban domestic sewage are more prominent. Notably, the environmental pollution has a significant cumulative effect, which is not reversed. Therefore, a pollution shock in one period may leave the region permanently further behind. Based on this, in the follow-up process of pollution control, we should fully consider the heterogeneity in coping ability of individuals. While promoting industrial wastewater emission reduction, we should emphasize strengthening of the urban domestic sewage treatment strategies and give overall consideration to the ecological environment treatment and regional coordinated development.

Developing an Ensembled Machine Learning Prediction Model for Marine Fish and Aquaculture Production

The fishing industry is identified as a strategic sector to raise domestic protein production and supply in Malaysia. Global changes in climatic variables have impacted and continue to impact marine fish and aquaculture production, where machine learning (ML) methods are yet to be extensively used to study aquatic systems in Malaysia. ML-based algorithms could be paired with feature importance, i.e., (features that have the most predictive power) to achieve better prediction accuracy and can provide new insights on fish production. This research aims to develop an ML-based prediction of marine fish and aquaculture production. Based on the feature importance scores, we select the group of climatic variables for three different ML models: linear, gradient boosting, and random forest regression. The past 20 years (2000–2019) of climatic variables and fish production data were used to train and test the ML models. Finally, an ensemble approach named voting regression combines those three ML models. Performance matrices are generated and the results showed that the ensembled ML model obtains R2 values of 0.75, 0.81, and 0.55 for marine water, freshwater, and brackish water, respectively, which outperforms the single ML model in predicting all three types of fish production (in tons) in Malaysia.

The potential study of marine aquaculture location in Eastern Bintan Island

Bintan is one of Indonesia’s islands, consisting of nearly 2408 small islands and directly adjacent to Singapore and Malaysia. The strategic geographic location and many small islands and supported by 95% of the sea area give Bintan Island an advantage in developing the marine aquaculture sector. This study aims to apply remote sensing analysis to collect comprehensive information on the strategic Marine Aquaculture Zone (MAZ) in the eastern part of Bintan Island. The data used in this study were the concentration of chlorophyll-a (Chl-a) and Sea Surface Temperature (SST) from MODIS level-3 with a resolution of 4 km from January to December 2019. The pre-processing data analysis on SST and Chl-a concentrations was used SeaDas software to ensure the results of the data projections in the form of the World Geodetic System 84 (WGS84) format. The data processing stage uses ER Mapper software to project the SST distribution and Chl-a concentration into a contour. Post-processing data analysis was used ArcGIS software to determine the results of crossing the SST contour and Chl-a combination to obtain the optimal potential location for the Marine Aquaculture Zone (MAZ). Image data processing shows the lowest potential marine aquaculture location was in Bintan Island in West Season with 202 MAZ. The highest potential location for marine aquaculture on Bintan Island in North Season with 584 MAZ. The results showed the potential location for marine aquaculture locations in Bintan Island was widely distributed, and most of the locations far from the coastline of eastern Bintan Island. This study indicates that the east part of Bintan Island has the potential to be implemented for marine aquaculture areas to develop sustainable marine aquaculture production.

Sarcocornia neei: A novel halophyte species for bioremediation of marine aquaculture wastewater and production diversification in integrated systems

The integration of bioremediation systems is one of the most promising techniques to mitigate the environmental impact of aquaculture effluents. Also, it allows nutrient recycling, production diversification, and the creation of high-value by-products. In marine aquaculture, where the implementation of salt-tolerant extractive species is essential, halophyte plants have demonstrated to be optimal candidates for bioremediation of saline aquaculture wastewater.This study aimed to evaluate for the first time the efficiency of Sarcocornia neei (Lag.), a halophyte plant with high adaptability, salinity tolerance and growth potential when irrigated with seawater, in removing nutrients from marine fish aquaculture wastewater and artificial effluents. Two experiments were carried out. In the first one, the growth rate, removal of inorganic nutrients, and accumulation of organic compounds in deep-water hydroponics and sand-substrate systems were evaluated in artificial effluents with different nitrogen and phosphate loads during 70 days. In the second, due to the better performance achieved by S. neei in deep-water systems, its nitrogen removal efficiency and productivity rates were evaluated in deep-water aquaponics with marine aquaculture wastewater and artificial effluents at higher nitrogen loads during 61 days.The highest productivity rates achieved by S. neei (14.41 ± 0.78 kg m−2) were obtained in deep-water culture units, reaching 100% plant survival, suggesting that this species is more suitable for its implementation in this type of system. Significant total ammonia nitrogen removal rates were obtained by the plants, achieving a maximum in sand-substrate systems (0.68 ± 0.41 g m−2 day−1). The results of nitrate removal rates obtained by S. neei (11.25 ± 31.38 g m−2 day−1) make this species an ideal potential candidate for the removal of this compound present in marine RAS effluents. Accumulation of organic compounds was corroborated by obtaining a significant increase (p < 0.05) in organic N (31.2 ± 0.1 mg g dry weight−1) and organic P (4.0 ± 0.6 mg g dry weight−1) content in plant biomass at the end of the trials.These results indicated that S. neei is a good candidate for its use as a biofilter for marine aquaculture wastewater. Further investigations should be done to analyze possible influences on growth rates and nutrient removal efficiency by adding essential micronutrients, adjusting effluent salinity, and implementing different plant densities. Also, further studies could be interesting to determine the feasibility of long-term integration of a bioremediation system with S. neei associated with marine aquaculture effluents, approaching its application to industrial-scale production systems.