Showing papers in "Reviews in Aquaculture in 2016"

Mineral requirements of fish: a systematic review

Abstract: Meta-analysis of literature data on mineral and trace element requirements of fish was performed with the major objectives of identifying appropriate response criteria and the factors affecting the minimal dietary inclusion levels. The primary data set included 25 studies on available P, 20 on Ca, 24 on Mg, 5 on K, 37 for Zn, 23 for Se, 19 for Mn, 16 for Fe and 13 for Cu. Broken line regression analysis with linear plateau model (P, Ca, Mg and K) or two-linear line model (Zn, Cu, Fe, Mn and Se) was used for determining the minimal dietary inclusion levels. Vertebral mineral concentration (P, Ca, Zn and Mn), whole-body mineral levels (Mg, K and Fe) and hepatic enzyme activity (Se) were found to be the most appropriate criteria for the respective minerals analysed. In general, weight gain as the criterion resulted in a lower estimate (by 18–42%) than those obtained using whole-body or vertebral mineral concentrations as response criteria. The analysis also showed that different fish species do not show large variations in the mineral and trace element concentrations in the whole body and tissues. Factors such as species group and digestive physiology, type of experimental diet used and dietary interactions, type of mineral source and mineral concentration of water were found to affect the minimal dietary inclusion levels of certain minerals. Besides the meta-analysis, research needs in mineral nutrition of fish with reference to growing changes in dietary strategies and rearing systems are discussed.

Probiotic, prebiotic and synbiotic supplements in sturgeon aquaculture: a review

Abstract: This study addressed the issue of the dietary supplements; probiotic, prebiotic and synbiotics considered as functional food ingredients in sturgeon aquaculture. Developments of this strategy have been suggested and practiced as an alternative to antibiotic administration in aquaculture. Sturgeons are commercially valuable species due to their meet and roe, which is made into caviar. Aquaculture of sturgeons up to marketable size has increased during the last decade while disquieting decreases have been noticed of the natural populations. In line with the expand evaluations of microbial dietary supplements and prebiotics in finfish and shellfish aquaculture, the scientific community has also increased their interest in approaches to these issues in sturgeon aquaculture. The present review summarizes and discusses the results on intestinal microbiota of sturgeon species and the effects of probiotic, prebiotic or synbiotic administration on growth performance, gut physiology, intestinal microbiota, immune response and health. Furthermore, this study tries to cover the gaps of existing knowledge and suggest issues that merits further investigations.

Is integrated multitrophic aquaculture the solution to the sectors’ major challenges? – a review

Abstract: The growing demand for fish products and the dwindling productivity of marine fish stocks due to the overexploitation of fisheries place the aquaculture industry as a key contributor to the global fish supply. The intensive development of aquaculture has raised a range of environmental concerns such as effluent discharge, excessive use of resources and dependence on commercial feed. In this context, the development of sustainable aquaculture systems is becoming the cornerstone for long-term aquaculture expansion, and to achieve environmental sustainability. Integrated multitrophic aquaculture (IMTA) is regarded as a suitable approach to limit aquaculture nutrients and organic matter outputs through biomitigation. The cocultured species are used as biofilters, and each level has its own independent commercial value, providing both economic and environmental sustainability. Here, environmental issues of aquaculture and the current status of IMTA are reviewed and its future prospects discussed. Also, the opportunities to expand this systems’ complexity with increased added-value and trophic levels are introduced.

A review on fish growth calculation: multiple functions in fish production and their specific application

Abstract: Modern aquaculture recirculation systems (RASs) are a necessary tool to provide sustainable and continuous aquaculture production with low environmental impact. But, productivity and efficiency of such RAS still have to be optimized to ensure economic viability, putting growth performance into the focus. Growth is often reported as absolute (gain per day), relative (percentage increase in size) or specific growth rate (percentage increase in size per day), based on stocking and harvesting data. These functions describe growth very simplified and are inaccurate because intermediate growth data are not considered. In contrast, nonlinear growth models attempt to provide information of growth across different life stages. On the basis of an empirical RAS data set of 150 all-female turbot reared in an RAS during a period of 340 days of outgrowth, this paper reviews the most commonly used growth rates (relative, absolute, specific), the thermal-unit growth coefficient and five nonlinear growth functions (logistic, Gompertz, von Bertalanffy, Kanis and Schnute). Goodness of fit is expressed by R-2 and as mean percentage deviation. Nonlinear growth models are also compared by their residual standard error (RSE) and the Akaike information criterion. All processed functions are modelled to illustrate the shape of the generated curve and the possibility of the function to realistically predict growth. Further, the biological meaning of their regression parameters is discussed. This way we can point out differences in nonlinear growth models in contrast to purely descriptive growth rates and the specific advantages, disadvantages and possible applications of each function we review.

New developments and biological insights into the farming of Solea senegalensis reinforcing its aquaculture potential

Abstract: SM holds a Ramon y Cajal postdoctoral contract from the Spanish Ministry of Economy and Competitiveness (MINECO) and is supported by the European Commission Marie Curie Actions (FP7-PEOPLE-2010-RG, Project No. 274184). BC and SE are supported by Fundacao para a Ciencia e a Tecnologia, Portugal (SFRH/BPD/77210/2011 and SFRH/BPD/49051/2008, respectively).

Effects of environmental and farm stress on abalone physiology: perspectives for abalone aquaculture in the face of global climate change

Abstract: Many abalone farms are reliant on coastal water inputs which are subject to fluctuations in environmental variables such as temperature, oxygen, CO2 and salinity. Near future climate change scenarios predict that there will be more frequent extreme weather events which can exacerbate these fluctuations and potentially be deleterious to farmed abalone where these variables remain largely uncontrolled. In this review, we have taken an in depth examination of current literature on the effects of environmental stress on abalone physiology and metabolism and how this affects their health and growth. In conjunction, we have also reviewed the effects of farm-specific stressors such as ammonia, stocking density, handling, nutrition and disease and the synergistic effects of these and environmental stressors on abalone physiology. We have identified currents gaps in our knowledge of this under-studied species and have made predictions on the effects of climate change on future abalone production with suggestions for future research. In summary, it is expected that abalone will show reduced growth rates as more energy is invested in combating stresses rather than growth. Furthermore, disease outbreaks may become more frequent with greater fluctuations in temperature and salinity, both of which have large-scale effects on immunity. The current body of knowledge is mainly on whole animal effects of stresses, but we know very little of their mechanistic foundation. Research in this area as well as investments in infrastructure will be pivotal in identifying and implementing strategic interventions to maintain a sustainable abalone industry in Australia.

Transcriptional stress responses to environmental and husbandry stressors in aquaculture species

Abstract: Stress of aquatic animals occurs due to physical and physiological disturbances in the aquatic environment or system when transportation, crowding, handling or changes of physical and chemical factors take place. There are three regulatory systems having a vital role in stress response: the neural, endocrine and immune systems. Fish exhibit multiple genomic and physiological responses to adjust the compensatory or adaptive mechanism that allows them to mitigate the stressors, maintain their haemostasis and survive. In this review, we describe multiple important genes that are associated with responses to environmental and husbandry stressors and that could be used as biomarkers of environmental and husbandry stressors in fish. The described environmental and husbandry stressors include salinity, temperature, hypoxia and hyperoxia, confinement, density and handling. The main role of stress response in aquatic animals is to compensate or adapt their biological systems and arrange the metabolism to afford the energy required by the stressor and a wide array of metabolic processes and pathways are involved. We summarized and discussed highly significant genes in several organs and tissues that are involved and active during this adaption process. The traditional stress biomarkers in some circumstances have some difficulties in interpretation of results and lead to tricky diagnosis and searching and understanding alternative tools is critical for aquaculture, fisheries and fish welfare. Using genomic tools to study the candidate genes associated with stress responses are often unique signatures or imprints of specific stressors and could determine early signs of stressors.

Effectiveness of triploidy as a management tool for reproductive containment of farmed fish: Atlantic salmon (Salmo salar) as a case study

Abstract: Atlantic salmon (Salmo salar) dominates aquaculture production in its native North Atlantic range, raising concerns about the impacts of escaped farmed fish on wild populations. While physical confinement and operational management practices have improved steadily with the development of this industry, some escapes are inevitable. In the absence of effective measures for the rapid recapture of escaped fish, the only practical method currently available to minimize their impacts on wild populations is to ensure that they are female triploids and therefore reproductively sterile. The technology for producing all-female triploid populations of Atlantic salmon is simple and easily applied on a commercial scale, and routinely results in populations that are entirely female and >98% triploid. Aside from sterility, there are no population-wide phenotypic effects of triploidy, although triploids do tend to perform less well than diploids with respect to commercial culture characteristics and are also less likely than escaped diploids to outcompete or displace native salmon. Some uncertainties exist with respect to their disease resistance and their potential to become reservoirs for the spread of pathogens to wild populations. If the spawning potential of escaped farmed Atlantic salmon is deemed to pose an unacceptable risk to native populations, then all-female triploid populations could be used as an alternative to reduce risk. Research should continue to focus on improving triploid performance through breeding programmes and optimization of husbandry conditions (including nutrition, environmental conditions and fish health), with the goal of making triploids an attractive option for fish farmers.

A review of genotype-by-environment interaction and micro-environmental sensitivity in aquaculture species

Abstract: Generating breeding programmes that effectively improve farmed fish performance across multiple environments and make fish more uniform within production environments would aid farmers to produce food under diverse environments. We review genotype-by-environment interaction leading to re-ranking of genotypes across environments, that is non-unity genetic correlation between traits measured in different environments, and micro-environmental sensitivity leading to a change in environmental variance of a trait. A quantitative review across 38 species showed that (i) genotype-by-environment interaction studies are lacking for many economically important traits. (ii) Re-ranking is moderate for growth (average genetic correlation = 0.72) and survival (average genetic correlation = 0.54). Significant re-ranking is of concern because selection in a nucleus leads to lower genetic responses in commercial environments compared to a case when re-ranking does not exist. (iii) Re-ranking is weak for age-at-sexual-maturity and fish appearance (average genetic correlation = 0.86), implying that genetic improvement in one environment is expected to be effective in the other environments. Future research should provide guidelines for how to account for genotype-by-environment interaction when collecting data, estimating breeding values and optimising the structure of the breeding programme. (iv) Coefficient of genetic variation for sensitivity against unknown micro-environmental factors within a single environment for body weight is high. Hence, genetic improvement towards less sensitive fish, resulting in more uniform production, is possible, but a large number of relatives with phenotypes is needed for obtaining moderate accuracy of selection. This review elucidates needs for further research on genotype-by-environment interaction and micro-environmental sensitivity in economically important traits and species.

Coral aquaculture: applying scientific knowledge to ex situ production

Abstract: Coral aquaculture is an activity of growing interest due to the degradation of coral reefs worldwide and concomitant growing demand for corals by three industries: marine ornamental trade, pharmaceutical industry and reef restoration. Although captive breeding and propagation of corals is a well-known activity among aquarium hobbyists and public aquariums, the link between coral science and aquaculture is still poorly developed. Research on coral biology has increased in the past decades and resulted in abundant scientific information that is pivotal to further advance coral aquaculture. This review presents a holistic overview of coral aquaculture in relation to coral biology, with particular focus on ex situ aquaculture. Success factors for commercial coral aquaculture are outlined, which include qualitative aspects, such as shape, coloration and natural product content, and quantitative parameters such as growth and volumetric productivity. Manipulation of environmental factors to maximize coral quality and volumetric productivity is thoroughly discussed, and a comprehensive overview of current propagation techniques is provided. Knowledge gaps are pinpointed to indicate directions for future research.

Shrimp-based livelihoods in mangrove silvo-aquaculture farming systems

Abstract: The paper reviews the following three types of mangrove-shrimp systems: (i) integrated with canals between platforms planted with mangrove; (ii) associated having larger areas of water and a large mangrove area; and (iii) separated, with a dyke separating ponds from forest The variations in shrimp yield of integrated and associated systems, that is, mixed systems, are attributable to water exchange, % water surface, primary production, stocking of post-larvae, leaf litter fall and decomposition, species, cover and age of mangrove, and predators Leaf litter from all mangrove species except Nipa palm adversely affect water quality Leaf composition and decomposition rate vary between species; submersed leaves decompose faster Low concentrations of decomposing leaves of certain species temporarily boosted shrimp growth Shrimp yield has been found to be highest in ponds with 30–50% mangrove cover, but remained

Nutritional requirements and use of macroalgae as ingredients in abalone feed

Abstract: Temperate abalone species in aquaculture have a grow-out period of approximately 3 years because of their slow and heterogeneous growth rate. Abalone aquaculture is still a developing industry, and at least two major issues, nutrition and health, impede its development. Abalone are fed macroalgae on-farm in a number of countries, including China, Korea, South Africa and Chile. Formulated diets are crucial to the success of abalone aquaculture in countries where abalone do not grow readily when fed brown macroalgae or when access to macroalgae is insufficient for culture. Typically, the growth rate of abalone fed formulated diets is higher than abalone fed live macroalgae. However, due to a long production period, diets for abalone not only need to sustain high growth rates, but also maintain optimal health. Feeding live macroalgae improves the feeding activity, health and marketability of abalone. In this review, the nutritional requirements of abalone and dietary ingredients used in formulated diets will be discussed, together with the use of dried macroalgal meal as a dietary ingredient in formulated diets to improve the feeding activity, health and marketability of abalone in commercial production.

The quest for indigenous aquafeed ingredients: a review

Abstract: The growing demand for fish food products worldwide heightens the pressure on the current availability of feed ingredients, especially marine resources such as fishmeal and fish oil, for aquaculture feed production. To address this concern, the potential of novel ingredients for use in feed formulations needs to be tapped. This paper highlights recent researches undertaken concerning the dietary inclusion of various indigenous ingredients classified as seaweeds, leaf meals, oilseed meals, vegetable oils and medicinal herbs, and their effects on growth performance, feed intake, feed utilization efficiency, nutrient retention, disease resistance and other physiological activities among consumer species. Moreover, this paper presents information regarding their nutritive values, optimum inclusion levels and recommended protocols that can improve their potential as feed additives or fishmeal replacements.

Egg stickiness in artificial reproduction of sturgeon: an overview

Abstract: The egg structure of sturgeon is complex, with multiple micropyles and an envelope structure different from that of teleosts and other fish groups. In the sturgeon, an adhesive layer in the follicular epithelium is responsible for the egg adhesiveness. This is a problem for artificial reproduction of many fish species, including sturgeon, when a large number of eggs are incubated in hatchery conditions. Although several techniques for removing adhesiveness have been developed and successfully applied to eggs of common carp, tench, pikeperch and European catfish, de-sticking methods for sturgeon are limited. Proteolytic enzymes have been successfully applied to common carp, tench and African catfish eggs, leading to a hatching rate over 80% following 2-min treatment. In sturgeon, blue clay is the most commonly used de-sticking substance. The chemical reactions determining egg adhesiveness in sturgeon are poorly studied, and optimum methods for removing stickiness remain to be developed.

Disinfection of teleost eggs: a review

Abstract: In aquaculture hatcheries, egg disinfection is commonly employed as a mortality mitigation and disease management tool. In addition, disinfection protocols are utilized in research facilities, as a means to create axenic and gnotobiotic larval models. For the latter, a complete sterilization of the eggs is warranted. Multiple research groups have tested various disinfectants in fish eggs adopting different protocols and a range of parameters to evaluate their efficacy and safety. However, there is a clear lack of a critical review listing these different studies and stressing the advantages and shortcomings of the protocols and adopted disinfectants. This review provides a commented survey of the findings/experiments on the most frequently used and upcoming disinfecting products, the protocols in which they are included and their purposes with emphasis on decreasing bacterial and/or fungal load, underscoring the benefits and the limitations of each product. Supplemented with a critical note, this review assists both aquaculturists and researchers in making an informed choice. Moreover, it will help stakeholders to identify the gaps in knowledge where future research on egg disinfection is needed.

Review of the history, status and prospects of the black tiger shrimp (Penaeus monodon) hatchery sector in Bangladesh

Abstract: Culture of shrimp, mainly Penaeus monodon, makes an important contribution to Bangladesh’s aquaculture industry. Shrimp hatcheries are the foundation on which the shrimp industry is built. Hatchery performance and management therefore has extremely important implications for the long-term viability of the entire shrimp sector, especially given its vulnerability to diseases such as white spot syndrome virus (WSSV). This article provides a review of the history of shrimp hatchery development in Bangladesh and an overview of the current status of the shrimp hatchery sector and the challenges it faces. This article also provides a unique historical analysis of shrimp broodstock performance and rates of WSSV infection using data collected from hatcheries between 2007 and 2013. This reveals sharp declines in broodstock quality and performance over time, and high rates of WSSV infection, with potential major implications for the future sustainability of the sector.

Enhancing aquaculture development:mapping the tilapia aquaculture value chain in Ghana

Abstract: Fish is important in the diet of millions of Ghanaians supplying protein and micronutrients. Ghanaians have developed taste preferences for the consumption of Oreochromis niloticus (Nile tilapia), thereby booming the tilapia aquaculture industry. This paper looks comprehensively at the value chain of the tilapia aquaculture sector in Ghana to identify particular areas of intervention and development opportunities in achieving food security and nutrition needs, safety, quality and trade benefits. Mixed methods (including stakeholders’ workshop, interviews and document analysis from official sources) were employed in collecting data between January and December 2014. The analysis indicates that farmed tilapia products are currently not exported but locally consumed. In 2012, approximately 28 000 t of tilapia were supplied to the local market. The bulk of the supply came from cage culture (85%) with the remaining coming from ponds and dugouts. About 98% of tilapia coming from aquaculture is supplied directly to the local markets, whilst 2% is family consumed (subsistence). The marketing channel involves farmers selling to wholesalers/retailers and to consumers/restaurants in nearby villages or secondary towns. The processing technology is generally low (mainly sun drying, small size smokers). Currently, due to the growing middle-class Ghanaians, high domestic demand for fish and high levels of undernutrition among many poor Ghanaians, there is a good and readily available market for all sizes of tilapia produced locally. However, farmed tilapia has the potential for export to the international markets if it is processed as smoked and salted. To achieve this, there is the need to develop a practical guide for aquaculture exporters by the relevant stakeholders, strengthen capacity building of public institutions to deal with the export of aquaculture products and train more aquaculture personnel, and collate proper documentation of aquaculture products.

Estimating impact of white spot disease on economic risk in semi‐intensive shrimp farms in Mexico: the case of the State of Sinaloa

Abstract: We estimated the impact on economic risk associated with the prevalence of white spot disease in shrimp farms in the State of Sinaloa, Mexico. Farms located in the jurisdiction of Local Aquaculture Health Boards (LAHBs) were used for preparing estimates during 2008–2010. Probability distributions of economic losses were calculated by comparing net revenues obtained under normal operations and operations affected by the disease, using Monte Carlo simulation, to estimate the impact of prevalence on losses in absolute and relative terms, probability of losing and loss per unit risk at USD$484.27/ha, 28.9%, 72.9% and 0.20. Regression analysis allowed estimating that, by an increases of 1% in prevalence, there were increases in the estimators of risk of USD$11.49/ha, 0.96%, 0.47% and 0.005. Correlation analysis showed that there were significant differences in prevalence among LAHBs districts and years. The higher prevalence coincided with the districts and years that exhibited higher risk. The source of water and use of nursery systems were the main differences in operating conditions among the districts, possibly determining to a large extent the differences in economic risk calculated for the districts. Sensitivity analysis indicated that prevalence was the main factor determining risk. A significant inverse relationship was found between shrimp prices and prevalence, as a consequence of speculative market conditions. The possibility of using this relationship for syndromic surveillance is considered. We propose the use of the estimators employed in this study for assessment of economic risk associated with white spot disease (and possibly others) and standardization of results for future research.

Factors relevant to pre-veliger nutrition of Tridacnidae giant clams

Abstract: Tridacnid giant clams are of commercial interest for their nutritional, economic, and ecological significance throughout the Indo-Pacific and Oceania. A major impediment to culturing tridacnid giant clams is larval mortality, typically >96%. The effects of suspended and particulate nutrients on tridacnid veliger development have been examined, but factors relevant to the nutritional condition of oocytes and trochophore larvae are unknown. This is significant because the nutritional transition from trochophore to veliger coincides with rises in larval mortality. Our review examines culture techniques known to enhance gamete viability of several marine viable bivalves of commercial interest, and critically assesses whether such methods are applicable to tridacnids in culture conditions. Techniques for optimizing the nutritional requirements of pre-veliger tridacnids such as broodstock conditioning by supplemental feeding, monitoring the condition of oocytes ready for release, water temperature, egg attributes such as size and biochemical composition, and nutrient loads in culture water chemistry are examined. We include suggestions for optimizing nutritional conditions from gametogenesis through embryonic development, and conclude with a primer of research opportunities based on gaps in our understanding of tridacnid pre-veliger nutrition compared with other bivalves. A major conclusion is that culture protocols should include pre-veliger nutritional fitness as a critical factor in enhancing larval survival, growth and development.