Growth Of Aquaculture Research Articles

The role of the gut microbiome in sustainable teleost aquaculture.

As the most diverse vertebrate group and a major component of a growing global aquaculture industry, teleosts continue to attract significant scientific attention. The growth in global aquaculture, driven by declines in wild stocks, has provided additional empirical demand, and thus opportunities, to explore teleost diversity. Among key developments is the recent growth in microbiome exploration, facilitated by advances in high-throughput sequencing technologies. Here, we consider studies on teleost gut microbiomes in the context of sustainable aquaculture, which we have discussed in four themes: diet, immunity, artificial selection and closed-loop systems. We demonstrate the influence aquaculture has had on gut microbiome research, while also providing a road map for the main deterministic forces that influence the gut microbiome, with topical applications to aquaculture. Functional significance is considered within an aquaculture context with reference to impacts on nutrition and immunity. Finally, we identify key knowledge gaps, both methodological and conceptual, and propose promising applications of gut microbiome manipulation to aquaculture, and future priorities in microbiome research. These include insect-based feeds, vaccination, mechanism of pro- and prebiotics, artificial selection on the hologenome, in-water bacteriophages in recirculating aquaculture systems (RAS), physiochemical properties of water and dysbiosis as a biomarker.

Mind the gap between ICES nations’ future seafood consumption and aquaculture production

Abstract As the human population grows and climate change threatens the stability of seafood sources, we face the key question of how we will meet increasing demand, and do so sustainably. Many of the 20 International Council for the Exploration of the Sea (ICES) member nations have been global leaders in the protection and management of wild fisheries, but to date, most of these nations have not developed robust aquaculture industries. Using existing data and documentation of aquaculture targets from government and industry, we compiled and analysed past trends in farmed and wild seafood production and consumption in ICES nations, as well as the potential and need to increase aquaculture production by 2050. We found that the majority of ICES nations lacks long-term strategies for aquaculture growth, with an increasing gap between future domestic production and consumption—resulting in a potential 7 million tonne domestic seafood deficit by 2050, which would be supplemented by imports from other countries (e.g. China). We also found recognition of climate change as a concern for aquaculture growth, but little on what that means for meeting production goals. Our findings highlight the need to prioritize aquaculture policy to set more ambitious domestic production goals and/or improve sustainable sourcing of seafood from other parts of the world, with explicit recognition and strategic planning for climate change affecting such decisions. In short, there is a need for greater concerted effort by ICES member nations to address aquaculture’s long-term future prospects.

Effects of wave forces on knotless polyethylene and chain-link wire netting panels for marine aquaculture cages

The growth of offshore marine aquaculture requires improvements in the engineering and materials used for cage netting in order to better withstand wave forces. To clarify the hydrodynamic characteristics of knotless polyethylene (PE) and chain-link wire netting panels in non-uniform currents, we measured the wave forces acting on netting panels with varying solidity ratios and other parameters under regular wave conditions in a wave tank. The drag and added mass coefficients (CD, CM) were obtained using the Morison equation, and the behavioral trends in CD and CM for the netting panels were determined based on the Reynolds number (Re) and the Keulegan-Carpenter (KC) number. The experimentally derived coefficients were then incorporated into numerical simulations with the same conditions, and then were used to model the dynamic behavior of the netting panels. The normal CD of PE netting was similar to that in a uniform current and was positively associated with the solidity ratio, decreasing as Re increased. When the KC number was > 30, the normal CM of both the PE and chain-link wire netting remained unchanged, averaging 4.3 and 2.8, respectively. Large differences in displacement were observed for varying values of CD, suggesting that the effects of marine fouling should be considered during the design stage. Overall, these results provide a basis for further research toward a comprehensive hydrodynamic model for netting panels that can inform improved engineering for modern aquaculture.

Global adoption of novel aquaculture feeds could substantially reduce forage fish demand by 2030

With the global supply of forage fish at a plateau, fed aquaculture must continue to reduce dependence on fishmeal and oil in feeds to ensure sustainable sector growth. The use of novel aquaculture feed ingredients is growing, but their contributions to scalable and sustainable aquafeed solutions are unclear. Here, we show that global adoption of novel aquafeeds could substantially reduce aquaculture’s forage fish demand by 2030, maintaining feed efficiencies and omega-3 fatty acid profiles. We combine production data, scenario modelling and a decade of experimental data on forage fish replacement using microalgae, macroalgae, bacteria, yeast and insects to illustrate how reducing future fish oil demand, particularly in high-value species such as salmonids, will be key for the sustainability of fed aquaculture. However, considerable uncertainties remain surrounding novel feed efficacy across different life-cycle stages and taxa, and various social, environmental, economic and regulatory challenges will dictate their widespread use. Yet, we demonstrate how even limited adoption of novel feeds could aid sustainable aquaculture growth, which will become increasingly important for food security. Novel aquaculture feeds are rapidly developing, but their contributions to sustainable industry growth are unknown. Cottrell et al. model feed efficiency and fatty acid profiles, showing that replacing forage fish with novel feed ingredients could strengthen aquaculture’s role in global food security.

Are aquaculture growth policies in high-income countries due diligence or illusionary dreams? Foreseeing policy implications on seafood production in Singapore

In the beginning of 2019, the Singaporean government announced its desire to increase domestic food production and, in particular, aquaculture to reach 30% of self-sufficiency by 2030. Similar policies aiming at encouraging aquaculture growth abound in high-income countries in recent years, but have had limited success. Hence, this paper investigates the potential implications of such policies to foresee consequences beforehand and improve the policy’s chances of success. Three scenarios of aquaculture development are built for Singapore until 2040, among which a business-as-usual scenario and two explorative scenarios aiming at increasing aquaculture production, the first emphasizing existing technologies and the second giving priority to novel and innovative ones, like recirculating aquaculture systems. These scenarios are assessed using an adapted version of the supply-demand partial equilibrium model Asiafish to challenge their viability in the socioeconomic context of Singapore. Only the two explorative scenarios are found to allow the Singaporean government to reach its goal in terms of seafood self-sufficiency by 2030, one of which appears to have strong advantages. In this scenario, imports decrease by 28% by 2040, seafood self-sufficiency reaches 69% and 90% of all aquaculture originates from innovative technologies, which would make Singapore an aquaculture tech-hub. It also has higher benefits within Singapore environmental, social and economic constraints such as land and aquafeed scarcity.

Global stakeholder vision for ecosystem‐based marine aquaculture expansion from coastal to offshore areas

AbstractMarine aquaculture is the most promising industry for ensuring future provision of seafood. Yet, the worldwide growth and expansion of this industry have been slower than expected, calling for the identification of environmentally suitable sites while accounting for all factors that could constrain or benefit its establishment. Here, we determine the main obstacles and risks hindering the growth and expansion of marine aquaculture, as well as the needs and recommendations to overcome such constraints. Our analysis is based on results obtained from a consultation process held in 16 study sites located around the world with the participation of 614 stakeholders representing the research community, aquaculture industry, government, conservation groups, and education and fishermen associations. A high level of commonality exists in the main issues hindering aquaculture growth and expansion in coastal, off‐the‐coast and offshore aquaculture with most being attributed to interactions with other maritime activities, including conflicts with other users and administrative procedures, including licensing. Critical needs for improved management and expansion of the aquaculture industry are related to planning and management of developments and technological advances, with economic and market needs featuring to a lesser extent. Key procedures recommended to assist further aquaculture growth are the standardisation and simplification of regulatory frameworks, improvement of governance, and the adoption of participatory processes to facilitate meaningful and productive stakeholder engagement. We strongly recommend stakeholder participation to enhance insights on the full environmental and human dimensions of marine management and for implementation of ecosystem‐based marine spatial planning.

Improved performance of a rainbow trout selected strain is associated with protein digestion rates and synchronization of amino acid absorption

Replacement of fishmeal in feeds is critical for sustainable aquaculture growth. However, replacement with plant protein concentrates reduces fish performance. A rainbow trout strain selected for high performance on a plant protein diet was compared to a non-selected strain to identify physiological mechanisms associated with improved performance. Nutrient digestibility in fishmeal and plant protein diets was assessed and no strain differences were found. Levels of amino acids in the hepatic portal vein and caudal vein were measured at intervals after a single force-feeding of fishmeal, four plant protein concentrates, and a mixture of the concentrates with or without supplementation of three limiting amino acids. Each ingredient affected plasma amino acid levels in a singular manner when fed individually but without predictable additive effects when fed as a mixture. Amino acid supplementation altered uptake and plasma concentrations of all the essential amino acids. The selected trout strain fed the plant protein mixture with amino acids showed a synchronous and homogenous pattern for essential amino acids over time in the hepatic portal vein in contrast to that of the non-selected strain. The results demonstrate that selection favorably altered temporal dynamics of plant protein digestion.

Detecting spatiotemporal changes of large-scale aquaculture ponds regions over 1988–2018 in Jiangsu Province, China using Google Earth Engine

Although the aquaculture industry is a major supplier of aquatic products used as protein sources for humans, the rapid expansion of aquaculture in recent decades has led to numerous environmental problems in coastal and lakeside areas. Nonetheless, the spatiotemporal understanding of aquaculture ponds is limited, despite playing a crucial role in the management, planning, and development within the aquaculture industry. Remote sensing images can be used to acquire information pertaining to aquaculture; however, the automatic identification of aquaculture ponds remains an important challenge due to their complex spectral and spatial characteristics. This study utilized a decision-tree classifier using Landsat data derived from the Google Earth Engine (GEE) cloud platform to automatically identify large-scale aquaculture ponds in Jiangsu Province through seven time slices between 1988 and 2018. The results showed that the area allocated to aquaculture ponds in Jiangsu Provinces has continually increased from 660.29 km2 in 1988 to 4097.95 km2 in 2018, and three regions with dense aquaculture pond distributions have developed in the coastal zone, as well as in the south and center of Jiangsu Province. The area devoted to aquaculture ponds grew exponentially from 1988 to 2003 and later experienced a slower growth rate. Moreover, inland aquaculture pond areas began to decrease since 2013; however, a rapid expansion endures in the coastal area. Socio-economic development and industry policies are the main drivers of aquaculture growth; however, the strengthening of national environmental protection policies in the 21st century has contributed to a slowdown in these trends.

Hybrid grouper in Vietnamese aquaculture: Production approaches and profitability of a promising new crop

Grouper aquaculture is a rapidly growing and dynamic industry within Vietnamese aquaculture and an important source of local employment and income generation. Information on the state of current production practices and profitability for specific crops across different geographic locations and stages of production is difficult to obtain. This research contributes to wider efforts to address this knowledge gap by providing indicative findings on current market characteristics, production practice, and profitability of a ‘new’ aquaculture crop in Vietnam: Hybrid grouper (E. lanceolatus X E. fuscoguttatus). Participants in the study identified Hybrid grouper as the most important crop for grow out farms and the second most important crop for nursery farms due to strong market demand and sales prices, fast growth rate, and higher survival compared to other grouper crops. Research utilised a survey of 12 grouper farms in the Northern (Hai Phong) and Central (Khanh Hoa) provinces of Vietnam in mid-2018 to determine indicative financial production characteristics and gross margins (annual net sales revenue minus cost of goods sold) of nursery, cage, and pond enterprises that currently culture Hybrid grouper. Farmers indicated that the Hybrid grouper industry was segmented into three distinct phases of production: spawning, larval rearing and grow out. Few grouper farmers specialise in more than one area. Farmers in both study regions reported that Hybrid grouper were desirable due to the strong market demand and high sale prices, fast growth rate, and higher survival compared to other grouper crops. Farms had different economic characteristics between region and type, major differences were seen in the species cultured, number of people employed and age of farms. All farms interviewed generated annual net sales revenue exceeded the cost of goods sold. Earthen pond farms in Central Vietnam generated a median gross margin of US$ 8741 per year, Central region nurseries US$ 8059, and Northern Sea cage farms US$ 4562. Relative importance, calculated by contribution to total farm income, indicated that Hybrid grouper is the most important crop for grow out farms in both regions and second most important for nursery farms. Central region grow out farms generate higher gross margins than Northern Sea cage farms, which is a result of Central region grouper growing faster, having higher survival rates, and selling for more per kg than those grown out in the Northern region. The main changes to the industry since 2010 have been the introduction of Hybrid grouper as a new crop, the increase in average grouper sale price, and the move to full life-cycle aquaculture. Average sale price for grouper has increased from US$ 7.7–9.6/kg (adjusted to 2019 US$) to US$ 9–15/kg. The findings indicate that the most significant constraints to the growth and diversification of the grouper aquaculture industry in Vietnam are the limited availability of Hybrid fingerlings due to difficulties in larval rearing, and increases in feed costs due to a lack of domestic feed suppliers. Notwithstanding these constraints, the higher gross margins of Hybrid grouper relative to other financially viable grouper crops suggests continued, albeit moderated, growth of grouper aquaculture in Vietnam.

Selective breeding trait preferences for farmed tilapia among low-income women and men consumers in Egypt: Implications for pro-poor and gender-responsive fish breeding programmes

A number of studies have highlighted the promising growth of Egyptian tilapia aquaculture and the role of genetically improved strains in this development, such as the Abbassa Nile tilapia (Oreochromis niloticus, Linneaus, 1758). However, few studies have explored the link between aquaculture development and changes in fish demand among low-income consumers. This study combines household budgeting questionnaires and morphometric tilapia trait rankings conducted in the peak market season of 2017 to examine patterns of tilapia consumption and preferences among low-income women and men consumers across Egypt. Analysis of variance tests and a hierarchical logistic regression model were employed to determine effects of sex, age, educational status, household size, presence of children, food dependency ratio and location on tilapia consumption and trait preferences. Results showed significant differences in tilapia consumption between Lower and Upper Egypt. Greatest heterogeneity in tilapia trait rankings was found in preferences for total body weight, as well as for body width, body length and tilapia head traits. Models predicted that younger women consumers with children in Lower Egypt were more likely to consume smaller tilapia sizes and prefer larger tilapia head traits. This study offers the first evidence base of tilapia trait preferences of low-income consumers to genetic selection programmes considering the adoption of pro-poor and gender-responsive breeding objectives.

The successes of the reinvigoration and the vision for the next four years

The successes of the reinvigoration and the vision for the next four years

Applications of Spatial Autocorrelation Analyses for Marine Aquaculture Siting

Interest and growth in marine aquaculture is increasing around the world, and with it, advanced spatial planning approaches are needed to find suitable locations in an increasingly crowded ocean. Standard spatial planning approaches, such as a Multi-Criteria Decision Analysis (MCDA), may be challenging and time consuming to interpret in heavily utilized ocean spaces. Spatial autocorrelation, a statistical measure of spatial dependence, may be incorporated into the planning framework, which provides objectivity and assistance with the interpretation of spatial analysis results. Here, two case studies highlighting applications of spatial autocorrelation analyses in the northeast region of the United States of America are presented. The first case study demonstrates the use of a Local Indicator of Spatial Association (LISA) analysis within a relative site suitability analysis—a variant of a MCDA—for siting a mussel longline farm. This case study statistically identified 17% of the area as highly suitable for a mussel longline farm, relative to other locations in the area of interest. Use of a clear, objective, and efficient analysis provides improved confidence for industry, coastal managers, and stakeholders planning marine aquaculture. The second case study presents an incremental spatial autocorrelation analysis with Moran’s I that is performed on modeled and remotely sensed oceanographic data sets (e.g., chlorophyll a, sea surface temperature, and current speed). The results are used to establish a maximum area threshold for each oceanographic variable within the online decision support tool, OceanReports, which performs automated spatial analysis for a user-selected area (i.e., drawn polygon) of ocean space. These thresholds provide users guidance and summary statistics of relevant oceanographic information for aquaculture planning. These two case studies highlight practical uses and the value of spatial autocorrelation analyses to improve the siting process for marine aquaculture.

Seagrass debris as potential food source to enhanceHolothuria arguinensis' growth in aquaculture

Holothuria arguinensis aquaculture started to be developed in 2014, being the first sea cucumber species from Europe. However, some aspects of its aquaculture biotechnology, such diets, need to be assessed. This work aimed to evaluate seagrass debris of Zostera noltii and Cymodocea nodosa as food source for broodstock maintenance in tanks, during breeding periods. The given feed rations per tank were calculated as the 30% of the total sea cucumber biomass in each tank and reviewed each week. Then, feed rations of seagrass and sediment were calculated from this value, according to the following percentages: 40% sediment, 15% Z. noltii, 40% Z. noltii, 15% C. nodosa and 40% C. nodosa. H. arguinensis growth, feeding rate and nutritional value were assessed under these diets. H. arguinensis fed with 40% of Z. noltii showed the highest growth (specific growth rate = 0.09 ± 0.06%/day, absolute growth rate = 0.11 ± 0.07 g/day) increasing their final weight in 5.86 ± 3.57% in 57 days. However, the individuals fed with C. nodosa showed a negative growth. H. arguinensis showed a reduction in its feeding rate as the organic matter content in the diets increased. H. arguinensis did not show any important change on proximate composition, protein, lipid, mineral contents and fatty acids profile among the feeding groups, or in comparison with the individuals collected from wild habitat. Therefore, H. arguinensis could be fed with Z. noltii debris during tanks maintenance along breeding period, ensuring its growth and maintaining its nutritional profile.

Challenges and opportunities with aquaculture growth

This special issue of Aquaculture Economics and Management features five articles based on contributions to the International Association of Aquaculture Economics and Management (IAAEM) sponsored s...

Biofloc technology: principles focused on potential species and the case study of Chilean river shrimp Cryphiops caementarius

AbstractThe accelerated growth of aquaculture has caused environmental impacts in many countries. Examples include the use of large volumes of water, discharge of effluents with high nutrient content, the occupation of large areas, natural habitat alternation and the escape of exotic species. Biofloc technology (BFT) is an aquaculture tool that requires minimal water exchange, promotes the nutrient recycling optimizing resources and produces natural food in situ by forming suspended microbial aggregates in the water (bioflocs). These microorganisms provide multiple benefits such as water quality control, pathogen resistance and nutritional supplementation. Species such as Litopenaeus vannamei and tilapia have been successfully applied in BFT. In addition, there are also an increasing number of studies focused on alternative species with promising results. This paper describes essential aspects of biofloc technology, its application in aquaculture and the potential to extend its benefits to new aquaculture species such as Chilean river shrimp Cryphiops caementarius. This paper describes the future challenges of this technology as well as opportunities for its application.

Food Safety and Fish Farming: Serious Issues for Brazil

Fish farming in Brazil has been growing, and a new branch that has been taking up space and evolving, every year, as a source of leisure, is fish-pay. Despite being a leisure practice, this type of fish farming has contributed to the development of Brazilian aquaculture. With the growth of aquaculture in the country, concerns about the quality of the product arise, both financially and microbiologically. Aquaculture has caused some environmental problems, such as the increase in the population growth of bacteria specific to the aquatic environment and the possible proliferation of microorganisms resistant to antibiotics due to the indiscriminate use of these drugs in nurseries. Inadequate water quality conditions can contaminate fish and favor the development of diarrheal infections due to the microbiological load present in the fish. This article aims to review the literature covering the general characteristics of fish, including aspects of nutritional importance, and mechanisms of deterioration and analysis of freshness.

Exploring community-based marine aquaculture as a coastal resource management opportunity in Nova Scotia, Canada

Aquaculture is one of the world’s fastest growing food production sectors and presents an opportunity for rural community development that can support coastal livelihoods. An ecosystem approach to aquaculture (EAA) has been recommended to facilitate socially and environmentally sustainable development, yet there remains a need to better involve people in planning and operational aspects. Community-based management may help to implement principles of the EAA; however, context-specific research is needed to understand its potential application and suitability. This research explores opportunities for community-based marine aquaculture (CBMA) for nonfinfish in the context of Nova Scotia, Canada, through a series of stakeholder interviews. Results suggest that all stakeholder groups interviewed were positive about the potential for CBMA to support sustainable aquaculture growth in the province; however, key questions around operationalizing CBMA remain. The aquaculture industry is on a continual path for growth worldwide and, therefore, it becomes increasingly important to proactively examine strategies such as CBMA that can help to facilitate EAA in a way that genuinely puts people at the centre of aquaculture development and governance.

Biofloc Technology: Emerging Microbial Biotechnology for the Improvement of Aquaculture Productivity.

With the significant increases in the human population, global aquaculture has undergone a great increase during the last decade. The management of optimum conditions for fish production, which are entirely based on the physicochemical and biological qualities of water, plays a vital role in the prompt aquaculture growth. Therefore, focusing on research that highlights the understanding of water quality and breeding systems’ stability is very important. The biofloc technology (BFT) is a system that maximizes aquaculture productivity by using microbial biotechnology to increase the efficacy and utilization of fish feeds, where toxic materials such as nitrogen components are treated and converted to a useful product, like a protein for using as supplementary feeds to the fish and crustaceans. Thus, biofloc is an excellent technology used to develop the aquaculture system under limited or zero water exchange with high fish stocking density, strong aeration, and biota. This review is highlighted on biofloc composition and mechanism of system work, especially the optimization of water quality and treatment of ammonium wastes. In addition, the advantages and disadvantages of the BFT system have been explained. Finally, the importance of contemporary research on biofloc systems as a figure of microbial biotechnology has been emphasized with arguments for developing this system for better production of aquaculture with limited natural resources of water.

Legal regulations and consumer attitudes regarding the use of products obtained from aquaculture.

Aquaculture is an industrial activity that not only aims to be a source of quality food, but also is a way to restock fish populations and to conserve the biodiversity of our oceans. On the other hand, the production system can influence the consumer perceptions about what is purchased and consumed, as well as the subsequent environmental and social effects. Fish feeding production is affected by the growth of aquaculture and the increasing demand that have let to deficit, high prices, and low ecological safety of fish meal and oil. In this regard, the use of microbial biomass obtained from a variety of microorganisms has been reported as a potential substitute for plant- and animal-derived ingredients, satisfying the requirements in protein and energy and even adding functional properties. In addition, microalgae can increase the nutritional value of animal feed, play a key role in the physiological growth and external appearance of aquatic animals. Finally, politicians, industry and society in general should be careful with the numerous uncertainties still present in the sector that can weaken its sustainability from environmental, social and economic perspectives.

Evaluation of Filamentous Fungal Biomass Cultivated on Vinasse as an Alternative Nutrient Source of Fish Feed: Protein, Lipid, and Mineral Composition

The rapid growth of aquaculture and scarcity of conventional fish feed supplements has prompted the introduction of new sustainable supplementation sources. In this study, the potential of five strains of fungal biomass of Ascomycetes and Zygomycetes edible filamentous fungi, Aspergillus oryzae, Neurospora intermedia, Rizhopus oryzae, Monascus purpureus, and Fusarium venenatum, cultivated on vinasse, a by-product of the bioethanol industry, as alternative protein sources for fishmeal in the fish diet was evaluated. It was observed that 5% vinasse with an initial pH of 5–6.5 can support fungal biomass yields of 34.3 ± 2.4–118.5 ± 3.9 g DM/L for A. Oryzae, N. intermedia, and R. oryzae. High protein contents of about 44.7%, 57.6%, and 50.9% (w/w), and fat contents of 7.0%, 3.5%, and 5.5% (w/w) were obtained for A. oryzae, N. intermedia, and R. oryzae, respectively. The latter three fungi species contained noticeable amino acid contents, including promising profiles of amino acids that are highly compatible with those of fishmeal. These findings provide evidence that fungal biomasses, with their relatively high protein content, good amino acid profiles, and other essential nutrients, are a promising supplementation alternative that can be produced from low-value by-products and organic-rich waste streams like vinasse to meet the dietary protein requirements in fish feed.