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India is the world's second largest producer of farmed fish, and the state of Andhra Pradesh (AP) is by far the most important producer of farmed fish in India. Freshwater aquaculture has boomed in AP since the late 1970s, first with carps, then pangasius catfish. Over this period fish pond area and farmed fish production grew from nothing to reach 142,000 ha and 1.5 million tons, respectively. Despite its scale and dramatic consequences, the boom has received little attention in the international literature. The present paper addresses this gap by analyzing changes in the structure and conduct of each segment of AP's freshwater aquaculture value chain during four distinct phases of development (incubation, take-off, maturation and modernization). This analysis reveals that aquaculture development in AP shares many characteristics with agricultural commodity booms elsewhere in Asia. The paper contributes to the literature on crop booms by: 1) characterizing Southern domestic demand for agricultural products as an important but overlooked driver of agrarian development, and; 2) identifying interlinked processes of innovation and transformation in off-farm segments of the supply chain as a central feature of crop booms.

This paper provides the first continuous assessment of behavioural quiescence in Eastern oysters (Crassostrea virginica) overwintered at their northernmost (48°N) distribution range. The paper also describes how quiescent oysters respond to sediment burial, which may occur inadvertently when cultured stocks are lowered onto soft-sediment seabeds. Long term monitoring of valve opening indicated that quiescence persisted for 164.9 ± 1.8 days (mean ± SE, n = 14 oysters) in 2014–2015. Quiescence was initiated in mid-November 2014 when the water temperature fell to 2.7 ± 0.2 °C and ended in early May 2015 when the water temperature rose to 4.4 ± 0.4 °C. The low mortality rate (3.4 ± 1.9%) of the control groups indicated that this species is well-adapted to such overwintering conditions. When buried in late October, oysters initially exhibited low-amplitude and sporadic shell movements, possibly in an attempt to clear the sediment covering their valve margins. Following a period of quiescence, behavioural morbidity ensued, with lethargic opening of valves beginning 153.3 ± 9.9 days after burial (n = 16 oysters). Death occurred 186.5 ± 3.6 days following burial (n = 16 oysters). Removing buried quiescent oysters from the sediment in late winter accelerated the depletion of energy reserves, particularly lipids and proteins, thereby advancing death. In conclusion, detrimental health effects associated with the burial of oysters in autumn cannot be mitigated through winter or spring desiltation. Thus, reducing the risk of burial by avoiding soft estuarine sediment whenever possible remains the best husbandry practice.

The enteric septicemia of channel catfish, caused by Edwardsiella ictaluri, is one of the most severe diseases in channel catfish worldwide. Currently, a safe and highly effective vaccine is urgently needed for the control of this disease. In this study, E. ictaluri ghosts (EIGs) were first generated by PhiX174 lysis gene E, and the hematological indices and relative percent of survival (RPS) were examined in channel catfish (Ictalurus punctatus) after immunization. Generation of ghosts in the transformant of E. ictaluri carrying the plasmid pBV-lysisE was enhanced by increasing the incubation temperature up to 42 °C. Lysis of E. ictaluri occurred 2 h after induction and the process was complete in 6 h. The efficiency of ghost induction in non-lyophilized E. ictaluri was 99.997%. Additionally, no bacterial growth was detected by culture on BHI plates after lyophilization of the ghosts. The immune response of channel catfish immunized with the E. ictaluri ghosts indicated that the number of erythrocytes and leucocytes reached a maximum value of 3.53 × 106 and 5.25 × 105 cell/ml, at day 4 post-immunization, respectively, which were both significantly higher than in the control group inoculated with PBS only (P Statement of relevance In the paper, we illustrated the generation method of Edwardsiella ictaluri ghosts and the immunological responses and protection in channel catfish after being immunized with E. ictaluri ghosts. The result of this paper indicated that E. ictaluri ghosts would be an effective approach for preventing ESC in channel catfish in the future.

Feeding is a major factor that determines the production costs and water quality of aquaculture. Analysis of fish feeding behavior forms an important part of the feeding optimization. Fish feeding has generally been performed with automatic feeding machines which can lead to excessive or insufficient feeding. Recognition of fish feeding behavior can provide valuable input for optimizing feeding quantity. Due to the complexity of the environment and the uncertainty of fish behavior, the correlation and accuracy of behavior recognition are generally low. The accurate identification of fish feeding behavior till faces substantial challenges. This paper reviews the technical methods that have been used to identify fish feeding behavior in aquaculture over the past 30 years. The advantages and disadvantages of each method under different experimental conditions and applications are analyzed. Many methods are effective at evaluating and quantifying fish feeding intensity, but the recognition accuracy still needs further improvement. It is proposed by this paper that technologies such as data fusion and deep learning has great potential for improving the recognition of fish feeding behavior.

The implementation of gamete cryobanking in aquaculture may improve hatchery practices such as assisted reproduction and genetic selection of desired strains. This paper preliminarily investigated the technical feasibility of cryobanking semen of the common pandora Pagellus erythrinus, an important fishery resource in the Mediterranean area and a promising species for the diversification of productions. Post-thawing motility was evaluated in common pandora semen samples cryopreserved according to eight previously selected protocols and stored in liquid nitrogen for eight years. In order to mimic the practical use of long-term cryostored semen samples, the proportion of living sperm in which motility could be activated was evaluated, by computer-assisted analysis, on thawing and after 3 h of post-thawing incubation at 18 °C as biomarker of sperm viability. The assessed parameters were percentage of motile spermatozoa (TM), curvilinear velocity (VCL), lateral head displacement (ALH), beat-cross frequency (BCF) and dance (DNC). The cryostored sperm of the common pandora proved to have promising features. In fact, percentages of motile sperm higher than 40% were always obtained on thawing; moreover, the semen retained its activation ability in the times after thawing, showing no or slight alterations in the motility profile also when activated after 3 h of post-thawing incubation. The best post-thawing performances were recorded with the EG5%-based extender under the F1 curve (equilibration at 2 °C; freezing from +2 °C to −70 °C at 3.8 °C/min), that showed the highest percentages of motile cells (80 ± 3) and no significant alterations in any of the evaluated motility parameters, followed by the EG10% based extender under the F2 curve (equilibration/cooling from 20 °C to 2 °C at 1 °C/min; freezing from +2 °C to −150 °C at 23.3 °C/min). Such a post-thawing resistance of long-term cryostored samples, encourages further studies for the inclusion of the semen of the common pandora in cryobanks aimed at use in reproductive biotechnologies for aquaculture applications and as a model in laboratory research. Therefore, the present paper contributes to the implementation of semen cryobanking as a technological tool in support to aquaculture, using as a model a species of potential aquaculture interest. In addition, the creation of germplasm cryobanks for aquatic species comply with the EU ARRIVE (Animal Research: Reporting of in Vivo Experiments) guidelines that promotes a coordinate use and sharing of biological samples from animal models in laboratory research.

High incidence of cancer and other diseases have boosted the interest in herbal products to be used as alternatives to synthetic drugs worldwide. Plants that present biological activity are frequently processed, and their extracts are marketed as over-the-counter natural medicines. Such a trend is also observed in the aquaculture sector. The number of studies investigating the potential activity of plant-based products to substitute synthetic fish anesthetics has increased substantially over recent years. This paper summarizes the current data available and knowledge about the use of essential oils and active substances for fish sedation and anesthesia. Clove oil is the most commonly used plant-based anesthetic in aquaculture and several other studies have been conducted on the use of essential oils of basil, thyme, mint, rosemary, lavender, citronella, verbena and camphor for the different fish species. In recent years, active substances such as eugenol, menthol, myrcene, 1,8-cineole, linalool, limonene, citronellal, thymol, carvacrol, spathulenol, α- and β-pinene, 4-allylphenyl acetate and globulol, found as constituents of essential oils have also been investigated for sedation and anesthesia purposes in fish. This paper describes some of the sedative and anesthetic effects of essential oils and their active substances on the modulation of fish behavior, physiology and biochemistry. Such structured information could be useful for the aquaculture industry as natural anesthetics could be potentially more environmentally friendly, cost-effective and safer products than synthetic drugs for the management and welfare of aquatic organisms.

White spot syndrome virus (WSSV) is one of the most devastating pathogens, which inflicted huge losses to the shrimp farming sector in India and the world. The current study maps the WSSV research output during 1998–2017 using Web of Science (WoS) database. A total of 1786 tags were subjected to the present analysis which covers various parameters viz., growth, rank and global publications share, research collaborations and other bibliometric indicators like total citation counts, average citations per paper, and h-Index. India accounted for 17.24% of the global WSSV publications, and stood second among the 15 most productive countries in terms of number of publications in this period. The Indian researchers had networked with 23 collaborating partners across the world, of which USA, the lead collaborating country accounted for 18.51% of the total papers with international collaboration. The study showed a positive correlation between the grants awarded to the research laboratories and their research productivity. The paper provides quantitative analysis on the leading institutions and individual researchers, significantly contributing to the WSSV research in India. The journal Aquaculture carried the maximum number of research papers on WSSV from India (53 papers), followed by Fish and Shellfish Immunology (32 papers) and Diseases of Aquatic Organisms (25 papers). The analytical results of the present study provide insights into the trends of WSSV research in India and calls for concerted efforts to enhance focussed research on this significant threat to the 4.8 billion USD worth shrimp farming sector, which has the potential to reverse the fortunes of the farmers.

Rainbow trout is one of the promising cultivable fish species in coldwater and has enormous scope for its expansion in the Himalayan region. Being a low volume high value commodity, the trout has good potential for domestic consumptions as well as foreign export. In spite of having excellent positive traits and prosperity, the development and expansion of trout farming in Himalayas has yet to be intensified for large-scale productions. There are enormous aquatic resources in the form of river, reservoirs and lakes in the Himalayan region yet agricultural production of trout is very limited. This paper presents the available trout production system, available infrastructure and production trend highlighting the need of improved feed, infrastructure, improved strain, application of triploid trout production for stocking in cages and pens and also the possibilities of organic trout farming so as to clinch the production intensification, environmental management and trout promotion objectives. Based on 15 years experience of trout culture in India, potential success in trout production could be acquired through technological modernization, better governance and significant improvement in the management practices. The knowledge needed to form a comprehensive trout-farming ecosystem beyond farm activities has been suggested in this paper which will be useful not only to the country but also to the transboundary Himalayan region where trout farming is still rudimentary.

The Nan'ao Golden Scallop discussed in this paper is a new breed of noble scallop, Chlamys nobilis, produced by four generations of genetic breeding selections and two generations of culture demonstrations. Performed for the first time at Shantou University, the genetic breeding program was motivated by the need to reduce vulnerability and improve the adaptive capacity of noble scallops to the dynamic environment. This paper reviews the scientific evidences on aquaculture advantages of Nan'ao Golden Scallop, and identifies gaps in knowledge that require further research. From the analysis of published data, it is obvious that Nan'ao Golden Scallop is more nutritious and less susceptible to stress than common brown scallops. The high TCC of Nan'ao Golden Scallop up-regulate the expression of various immune related genes under stressful conditions. Since molluscs do not possess specific immunity, the information in this paper is very useful for improving the aquaculture performance of molluscs by selective breeding techniques.

The aim of the present study was to investigate the effect of dry salting, cold smoking and 14 days refrigerated storage at 4 °C on the stability of carotenoids, color and fatty acids in commercially reared organic Atlantic salmon (Salmo salar L.). As reference, conventionally reared Atlantic salmon was used. Pigment sources in feeds for the organic and conventional salmon were Panaferd-AX® (PAN) and Carophyll Pink® (CP), respectively. The dry salting process was found to be the main cause for losses of carotenoids throughout salting, smoking and storage, whereas no differences were found in stability of the different flesh carotenoids. The diverse composition of flesh carotenoids in organic salmon seems however to have minor influence on the color of the cold smoked product. Colorimetric characteristics of the fillet surface and liquid loss during storage of cold smoke fillets were found to be mostly affected by the fatty acid composition of the flesh which differed between the organic and conventional raw material. Moreover, dry salting and cold smoking were found to alter colorimetric differences between raw organically and conventionally reared salmon, resulting in an equal colorimetric perception of cold smoked organic and conventional salmon fillets after 14 days refrigerated vacuum storage. Statement of relevance: •This paper investigates the stability of carotenoids, color and fatty acids throughout processing and storage of cold smoked organic farmed Atlantic salmon. •This paper focuses on the diversity of carotenoids presented in organic salmon fed a feed containing Panaferd-AX and how these carotenoids affect the color of the smoked product. •This paper investigates the suitability of the presented organic salmon as raw material for the smoking industry. This is a submitted manuscript of an article published by Elsevier Ltd in Aquaculture, 9 October 2015.

The aim of the present study was to investigate retention of pigments and composition of fatty acids (FA) in farmed organic- and conventional Atlantic salmon fed commercial feed adapted to organic and conventional salmon farming, respectively. Moreover, stability of pigments, FAs and color was investigated throughout the fillet shelf life. No significant differences were observed in fish weight between organic- and conventional salmon (5.44 and 5.40 kg, respectively). However, the average condition factor (Cf) was significantly lower in organic (1.00) as compared to conventional salmon (1.15). The fillet characteristics of the organic salmon investigated were; similar total content of muscle carotenoids, lower content of astaxanthin, more diverse composition of muscle carotenoids, higher contents of SFAs and PUFAs, lower contents of MUFAs and significantly darker appearance as compared to a conventional salmon. Only small differences were however found regarding stability of carotenoids, Vitamin E, FAs and color during 22 day ice storage. Hence, the pigment stability for both groups was regarded as good. Statement of relevance: • The paper compare today's production of organic- versus conventional farmed Atlantic salmon. • The paper investigates the retention and stability of carotenoids from the pigment source Panaferd-AX in Atlantic salmon and in salmon flesh during ice storage. • The paper investigates the effects of different carotenoid compositions and fatty acid profiles on the flesh color throughout the fillet shelf life. This is a submitted manuscript of an article published by Elsevier Ltd in Aquaculture, 12 September 2015.

The environmental effects of fish culture operations are important issues in Michigan as well as many other parts of the world. The State of Michigan Department of Natural Resources operates the Platte River State Fish Hatchery (PRSFH) located near Honor, Michigan (USA). This facility has a restrictive discharge permit that limits the input of phosphorus into the Platte River that subsequently drains into a downstream oligotrophic lake (Platte Lake). The permit has been violated on occasion in recent years. Hatchery managers and operators need to understand the cause of these violations and prevent them in the future; and at the same time meet production goals to satisfy fishery management objectives. This paper describes the development and application of models designed to quantitatively analyze these issues. First, a bioenergetic growth and consumption model is developed for juvenile coho ( Oncorhynchus kisutch ) and Chinook ( Oncorhynchus tshawytscha ) salmon to quantify the relationship between fish production and by-product phosphorus loads. Next, phosphorus mass balance equations are used to calculate the phosphorus discharge from the facility as a function of the by-product phosphorus load and the efficiency of various phosphorus removal equipment and processes. The accuracy and consistency of the energy and mass balance equations are verified using extensive measurements. The ability of the model to successfully match various aspects of system performance supports the contention that the bioenergetic modeling approach developed here can provide reliable estimates of salmonid growth and feed requirements for a variety of food compositions, rations, and temperatures. This capability, along with knowledge of the effectiveness of phosphorus removal equipment, forms the basis of a practical operational and management tool. An example of model utility is presented that analyzes the PRSFH phosphorus discharge and provides insights into why permit violations occurred in 2009 but not in 2010. The model demonstrates how to avoid food waste caused by over feeding, lower the food conversion ratio, and evaluate the effectiveness of phosphorus removal treatment processes. A steady-state version of the model can be used by managers to establish production goals that avoid future violations of the phosphorus discharge limits. Statement of relevance The environmental effects of fish culture operations are important issues in many parts of the world. This paper describes the development and application of models designed to quantitatively analyze the relationships among fish production, by-product phosphorus loads, and the phosphorus concentration of the discharge following treatment. The ability of the model to successfully match various aspects of system performance supports the contention that the bioenergetic modeling approach developed here can provide reliable estimates of salmonid growth and feed requirements for a variety of food compositions, rations, and temperatures. This capability, along with knowledge of the effectiveness of phosphorus removal equipment, forms the basis of a practical operational and management tool. The model demonstrates how to avoid food waste caused by over feeding, lower the food conversion ratio, and evaluate the effectiveness of phosphorus removal treatment processes. A steady-state version of the model can be used by managers to establish production goals that avoid future violations of the phosphorus discharge limits.

This paper reports on successful hatchery production of the winged pearl oyster, Pteria penguin, without the use of live micro-algae. Larval nutrition was provided by commercially available micro-algae concentrates, Instant Algae® (“Isochrysis 1800®” and “Pavlova 1800®”, Reed Mariculture Inc., San Jose, CA, USA). Larvae were first transferred to settlement tanks on day 17 when their mean antero-posterior measurement (APM) was 240.2 ± 8.6 μm. Approximately 6.4% of larvae survived to day 17 and more than 700,000 eyed pediveligers were transferred to settlement tanks between day 17 and day 25. Approximately 33,000 spat were harvested from spat collectors on day 105, representing a survival rate of 4.7% from the eyed pediveliger stage. Growth and development of larvae in this study were superior to those reported in a prior study that used a ternary live micro-algae diet to feed P. penguin larvae. Our results indicate that the products used in this study proved nutritious for P. penguin larvae and supported normal growth and development through settlement. The use of commercially available micro-algae concentrates as a replacement for live micro-algae in pearl oyster hatcheries supports development of simplified larval rearing protocols, without live micro-algae culture, that are more appropriate to Pacific island nations. Statement of relevance This paper reports for the first time on successful hatchery production of pearl oysters without the use of live micro-algae. Successful replacement of live micro-algae with commercially available micro-algae concentrates as a larval food source supports development of simpler, cheaper hatchery facilities, and larval rearing protocols that are more appropriate to Pacific island nations.

Social interactions among individuals may affect individual productivity and welfare in aquaculture. Since social effects may have a genetic component, known as an indirect genetic effect (IGE), genetic selection may be a promising tool to simultaneously improve welfare and productivity in aquaculture. Here we compare two experimental designs that have been previously proposed for the genetic improvement of socially affected traits. We used stochastic simulations to compare a design where each group consisted of members of two families (2-FAM) with a design where each group consisted of members of three families (3-FAM). The 2-FAM and 3-FAM designs were compared using an equal number of groups (96 groups). The group size, i.e., number of individuals within each group, was either 30 or 60 individuals. Both designs were compared for the precision of estimated direct and social genetic parameters and for response to selection, either with or without a restriction on the rate of inbreeding. Four different schemes with a low variance (heritability for social effects or h S 2 = 0.1), a moderate variance ( h S 2 = 0.3), or a high variance ( h S 2 = 0.5) of the social genetic effects, and a negative correlation between direct and social genetic effects ( r A D , S = − 0.6) were compared. The negative r A D , S indicates competition between group mates. Differences in precision of estimated genetic parameters between both designs were small. At low h S 2 and group size of 30, the 2-FAM design was superior with respect to precision of social additive genetic variance. When the social genetic variance was small, a larger group size, e.g. 60 is recommended. The 2-FAM design resulted in a higher accuracy of selection for social and total genetic effects, but also in a higher rate of inbreeding compared to the 3-FAM design. When the rate of inbreeding was restricted to ~ 2%, the total response to selection was significantly higher for the 3-FAM design. In conclusion, the 2-FAM and 3-FAM designs differ little in accuracy of the direct and social genetic parameter estimates, while the 3-FAM design is superior with respect to the response to selection at a fixed rate of inbreeding. This study is particularly important for making decisions regarding experimental design when breeding for social genetic effects in aquaculture. Statement of relevance Communal or family rearing with a large number of animals in a group is common practice in aquaculture. Large variation in body size, which may inflate competition for feed, is generally observed in the communal rearing tank. In addition, cannibalistic or aggressive behaviour is frequently observed in a large variety of fish species. So far, the issue is addressed by management measures, such as size grading, which may be labour intensive. Sustainable solutions through selective breeding have not been tested. Previous studies compared two experimental designs for social interaction traits; groups composed of two families (2-FAM) and three families (3-FAM) with groups composed at random and found that the 2-FAM and 3-FAM designs were better with respect to genetic parameter estimates than designs with groups composed at random. It is however still unknown whether the 2-FAM or the 3-FAM design is better. Previous studies did not consider the rate of inbreeding when studying the designs. This paper describes the results from a comparison of the two experimental designs for estimating genetic parameters and obtaining response to selection, taking into account the rate of inbreeding. As such, this paper should be of interest to a broad readership including those interested in aquaculture genetics.

In order to understand the effect of low temperature shock to Apostichopus japonicus , we measured the concentration of soluble proteins, soluble sugars and five ions (Ca 2 + , Mg 2 + , Na + , Cl − and NO) derived from different organs to evaluate the adaptive capacities and stress responses to mild temperature decrease (MTD, initial temperature was set at 14 °C and decreased from 8 °C to − 2 °C by step changes of 2 °C, temperature was decreased to each temperature through 24 h) and to rapid temperature decrease (ATD, step changes of 2 °C over 1.5 h) in the laboratory. Two commercial strains of A. japonicus , hybrid Shuiyuan No. 1 sea cucumbers (Ss) and Dalian local sea cucumbers (Ls), were used as test animals. In the MTD treatments, concentrations of soluble proteins and soluble sugars on the whole showed similar trends of an initial increase, a subsequent decrease and then an increase to a level similar to or higher than the initial level. Ca 2 + concentration increased to the maximum level at 4 °C and did not return to the original concentration. The concentrations of Mg 2 + and Cl − increased significantly to a higher level, which was maintained until the end of the experiment. However, the concentrations of Na + and NO showed an opposite trend: an initial decrease in concentration to a low concentration that was maintained until the end of the experiment. In contrast, in the ATD experiment, the concentration of soluble proteins, soluble sugars, Mg 2 + , NO and Na + showed a tendency for fluctuation or decrease. Only Ca 2 + and Cl − concentrations showed a rising trend. Earlier responses and faster homeostatic ability were observed for Ss individuals than for Ls individuals, indicating a greater cold tolerance. Such findings provide the basis for improving aquaculture techniques for A. japonicus , particularly for providing a new stress-resistant sea cucumber variety for A. japonicus culture in farm ponds. Statement of relevance The manuscript titled “Stress responses to mild and acute temperature decrease for two strains of sea cucumber Apostichopus japonicus ” was finished by Junhao Ning, Yaqing Chang, Wei Liu, Jian Song, Weijie Zhang and Jun Ding, we all made contribution to this manuscript and agreed with the authors' sorting order. This paper is first submitted in your journal. Neither the entire paper nor any part of its content has been published or has been accepted elsewhere. It is not being submitted to any other journal. We believe the paper may be of particular interest to the readers of your journal because the study reports that: (1) a preliminary relationship between the changes of soluble proteins, soluble sugars and five biogenic ions in A. japonicus and cold stress is established in the study; (2) the turning point of stress reaction in A. japonicus when suffering low-temperature was found at 0 °C or at 2 °C; and (3) we provide a new stress-resistant sea cucumber variety for A. japonicus culture in farm ponds.

In the pioneering period (1970s) of Norwegian salmon and trout aquaculture, the biological knowledge underlying this industry evolved in an institutional world of open science. Universities developed novel breeding techniques, and small grow out mom-and-pop farms implemented them. Eyed eggs were generic and standardized products, and traded at the lowest possible cost. As an eyed egg, the fry and in particular the eyes are visible through the membrane. The interplay between the regimes of open science and proprietary science has changed significantly in salmon aquaculture over the last two decades. One aspect of this change is that husbandry breeding has become more industrialized and subsequently more controlled by large, specialized and capital intensive breeding corporations. This paper explores this development from the perspectives of process-oriented institutional theory. We identify critical junctures in the coevolution of the breeding and grow-out sectors, and analyze how these junctures structure and change the direction of industrial and economic development. Ultimately, the generic, standardized and undervalued eyed eggs were subject to revaluation by the novel dominant international actors in the Atlantic salmon industry. We primarily draw data from interviews with core actors and informants at relevant universities, breeding companies and governmental agencies, as well as from white papers and other secondary material.

Spiny lobster farming is a feasible strategy to address increasing export demand currently not met by the capture fishery. However, farming currently relies on natural lobster seed availability, which in turn is limited by the fishers' lack of skill in catching and handling pueruli as well as applying suitable grow-out practises. In Indonesia, particularly on Lombok, a viable puerulus fishery has been established supporting a local grow-out industry. Anecdotal evidence suggests water depth may be an important factor for the effectiveness of collecting equipment. This paper reports on an experiment that examined the effect of depth and trap type on the effectiveness of puerulus collectors at the end of the wet season, when pueruli abundance is greatest. Four trap types were deployed at 5 depths: i) 1 m below surface; ii) 2 m below surface; iii) middle of the water column; iv) 1 m above the sea floor; and v) touching the sea floor, with 6 replicates of each. The data were analysed to identify the effect of depth and trap type using a two-way ANOVA. Significant differences for depth and trap type were found for the primary species caught, Panulirus homarus and Panulirus ornatus . The greatest catch of P. homarus was on the sea floor using a cement paper trap. For P. ornatus catch rate was less strongly correlated with a specific depth or trap type, although catch was highest at or near the sea floor in cement paper traps.

The rapid growth of the aquaculture sector over the past forty years can be closely linked to advances in science and technology. Some innovations in biotechnology have proven more controversial than others, and none more so than proposals for transgenic fish. Such innovations introduce concerns for the responsible governance of research and innovation for aquaculture, particularly in recognition of the significant uncertainties and high stakes characterising these technologies. This paper argues in favour of a participatory approach to the governance of contentious aquaculture technologies that includes an ‘upstream’ regard for their ethical and social implications. From this point of departure, the paper presents empirical research that employed one particular approach to engage aquaculture stakeholders from Northern Europe in deliberation over the ethical and social considerations of transgenic growth-enhanced salmon, using the ‘ethical matrix’ tool. This research explores the complexity of considerations raised by these small groups of diverse and knowledgeable stakeholders across workshops in Germany, Norway and the United Kingdom, and links them with wider ethical discussions in the bioethics literature. The dual ambitions of the paper are to first provide insights into an applied approach for incorporating ethical reasoning in processes for responsible aquaculture techno-innovation, and second to provide an appreciation for the plurality of considerations that decision-makers need to navigate and carefully weigh when reaching a decision on the appropriateness of the particular transgenic growth-enhanced salmon.

Despite fish being a rich source of animal nutrients and having numerous associated health benefits, it is an extremely perishable food, prone to a wide range of hazards. The bacterial load associated with shelf-whole-fish organs (e.g. digestive tracts and skin) or mishandling of fish may be a vehicle of infection and become a risk to public health. The objective of this paper is to evaluate the microbiological quality of whole ungutted and filleted shelf-tilapia, as well as assess the safety for human consumption. For this purpose, in order to investigate the distribution and occurrence of bacterial populations, the count of total and thermotolerant coliforms, coagulase-positive Staphylococcus and presence of Salmonella spp. was determined. This paper shows that all fish organs were contaminated with thermotolerant coliform. Skin and fillet show higher populations and occurrence of all microorganisms analyzed. Lower bacterial populations were recovered from the gut and muscles of whole tilapia. Two samples of fillet were contaminated with coagulase-positive Staphylococcus. It can be concluded that the skin and filleted tilapia are important carriers of food-borne pathogens. In addition, fish might become an important cross and self-contamination source.

Vertical mixing is an important aspect of the sea-cage hydrodynamic since it is directly related to the reduction of the potential environmental risks of sea-cage farms. Previous studies have focused on the enhancement of vertical mixing due to the water blockage of the sea cage through numerical simulations and laboratory experiments. However, these experimental settings inevitably deviated from the field hydrodynamic environments where vertical mixing was contributed by not only the water blockage of the sea cage but also some natural dynamic processes. This paper investigated the vertical mixing in a sea-cage farm located in a strong tide system through an in-situ method. The results indicate that the mixing could be divided into three regimes, namely, the bottom-boundary-layer regime (BBL regime), the regime generated by the baroclinic process during the currents reversal (CR regime), and the regime mainly located under the cage bottom (CB regime). The first two regimes were generated by natural dynamic processes, while the latter one was caused by the water blockage of the sea cage as illustrated in previous studies. Highlight of this paper was the identification of the interaction between the BBL and CB regimes, i.e., the interaction between mixing driven by natural dynamic processes and the artificial sea cage. The mixing in the bottom layer was significantly enhanced by this interaction and can maintain strong for a longer duration than that generated by natural dynamic processes alone. The nutrients concentration and the size distribution of the suspended particulate matter (SPM) were chosen to illustrate the environmental influences of the vertical mixing in the sea-cage farm. The nutrient release from the sea bottom was enhanced by the local vertical mixing, and the concentrations of NO2−, PO43−, and SiO32− increased when the mixing was strong. The principal variation in the NO3− concentration was independent of vertical mixing but was controlled by the alternation of the water masses. The size variation of the SPM was negatively correlated with the intensity of the vertical mixing. The results in this paper inspire us to create a suitable vertical-mixing environment in future sea-cage farms by taking advantage of the interaction between the mixing generated by the artificial sea cage and natural dynamic processes, thereby reducing the potential environmental risk and guaranteeing the sustainable development of the sea-cage farming.

Population increase, food security, employment, stresses on the fresh water resources and uncertainty associated with wild fish stocks are key parameters driving the demand for aquaculture expansion. Limitation in adequate waters in the coastal and near-shore sites for aquaculture development and the interactions within and from other coastal services forces the fish farming industry to move further offshore. Impact on the environment is an increasing concern that has to be considered in any aquaculture system designing. Moving further offshore could provide a better return on investment through various factors such as reduced mortality, better growth rates, less diseases and net fouling. However, moving offshore comes with a new set of challenges in withstanding severe weather conditions and safe and economic functioning of the aquaculture systems. Currently, the offshore fish cage design concepts are in their infancy and there is a race towards an optimum cage design for the offshore environment. Hence, in the aim of deriving an optimum cage design concept, this paper attempts to apply a holistic and theoretical approach to fish cage designing. By the application of theory of design, but different from the traditional engineering designing process, the paper proposes a conceptual framework and a cage design concept for offshore fish cage designing.

Gracilaria lemaneiformis , as an agarophyte, is an economically important marine alga in China. Breeding varieties of heat-tolerance may prolong the cultivation period for G. lemaneiformis and extend cultivation area. The mechanism of response of G. lemaneiformis to heat stress has become a topic of concern and subsequently initiated investigative research. In this paper, heat shock protein 70 genes ( hsp70-1 and hsp70-2 ) were cloned from G. lemaneiformis by RACE and Genome Walking. The open reading frame of hsp70-1 was 1977 bp, encoding 658 amino acids. The DNA of hsp70-1 had only one exon and the obtained 5′-flanking region was of 484 bp. The open reading frame of hsp70-2 was 2001 bp, encoding 666 amino acids. The DNA of hsp70-2 had only one exon as well and the obtained 5′-flanking region was of 730 bp. Hsp70-1 and hsp70-2 were found to be 69% ‘similar’ by the NCBI BLASTN program. An endoplasmic reticulum targeting sequence – HDEL – was found in HSP70-2. Homology analysis showed that the highest percentage of similarity (92%) between G. lemaneiformis and Porphyra yezoensis was in HSP70-1. The highest percentage similarity for HSP70-2 between G. lemaneiformis and Monosiga brevicollis was 77%. After heat shock, transcription levels in hsp70-1 increased sharply. Transcription levels of hsp70-2 were lower than hsp70-1 . With extended heat shock time, a similar trend was found between the two genes. It is supposed that hsp70-1 and hsp70-2 both are inducible, and at high temperatures, HSP70-1 is most active while HSP70-2 plays more of a supportive role. The results also showed that the transcription levels of the two genes in heat tolerant cultivar 981 were markedly higher than those of wild strain. This paper confirms that HSP70 plays an important role in the heat resistance of G. lemaneiformis , and that it may act as an indicator for breeding of the heat-resistant strain.

The digestive tract of fish is essentially a muscular tube lined by a mucous membrane of columnar epithelial cells that exhibit regional variation in structure and function. In the last two decades, our understanding of translocation of bacteria in the fish gut has increased, and electron microscopy has contributed to this knowledge. Translocation is the movement of viable and non-viable bacteria and bacterial products (such as endotoxin) from the intestinal lumen through the epithelial mucosa to infect otherwise sterile tissues. This paper provides an overview of the gastrointestinal tract of larvae and fry from an electron microscopical perspective focussing on factors (mucus, interactions between probiotics and pathogens, and stress) affecting translocation of bacteria (transcellular and paracellular), cellular damage (specific attack on tight junctions and desmosomes caused by pathogenic bacteria) and pathogenesis. Furthermore, the paper will present information on the occurrence and translocation of pathogenic bacteria in the gastrointestinal tract of larvae, fry and adult fish. Currently, it is generally accepted that the major routes of infection in fish are through the skin, gills and gastrointestinal tract. As the gastrointestinal tract is a potential port of entry for pathogens, the use of electron microscopy in studies on microbiota in fish digestive tract is a valuable method for increasing our understanding of the mechanisms involved in entry of the pathogens. Possible mechanisms involved in translocation of bacteria in fish gastrointestinal tract, autochthonous (indigenous) and pathogenic, are discussed.

Mulloway is an Indo‐West Pacific sciaenid fish with a short history of commercial culture in Australia. In January 2005, a harvest sample of these fish cultured off South Australia was observed macroscopically with large numbers of a blood‐feeding polyopisthocotylean. Epizootics of this parasite may pose a threat to the economics of farming this species, since it appears to be associated with anemia, as indicated by pale gills. Based on morphological characters, we identify the monogenean as Sciaenacotyle sciaenicola [Murray, F.V., 1932. Correction: note on a microcotylid from Sciaena antarctica. Parasitology 24, 448.] Mamaev [Mamaev, Yu.L., 1989. On species composition and morphological features of theMicrocotyle genus (Microcotylidae,Monogenoidea). In: Lebedev, B.I. (Ed.), Investigations in Parasitology. Collection of Papers. DBNTs AN SSSR: Vladivostok, pp. 32–38 [In Russian].]. Maximum likelihood analysis of ITS2 rDNA confirms that the genus Sciaenacotyle is not closely related to two other microcotylid genera also known from sciaenid fishes: Diplostamenides (represented by D. sciaenae (Goto, 1894) Mamaev [Mamaev, Yu.L., 1989. On species composition and morphological features of the Microcotyle genus (Microcotylidae, Monogenoidea). In: Lebedev, B.I. (Ed.), Investigations in Parasitology. Collection of Papers. DBNTs AN SSSR: Vladivostok, pp. 32–38 [In Russian].] from white croaker, Pennahia argentata, in Japan) and Anchoromicrocotyle (represented by A. guaymensis [Bravo‐Hollis, M., 1981. Helminths of fish of the Mexican Pacific. XXXVI. A new genus and subfamily of the familyMicrocotylidae Taschenberg, 1879 emended. An. Inst. Cienc. Mar Limnol. Univ. Nac. Auton. Mex. 8, 305–313.] from white seabass, Atractoscion nobilis, in California). In more intensive sampling of gills, we detected two other species of metazoan parasites, the monopisthocotylean Calceostoma glandulosum Johnston et Tiegs, 1922; and a copepod we identify as Caligus cf. elongatus, a sea louse very similar to C. elongatus Nordmann (1832), which affects farmed salmonids in the North Atlantic. Praziquantel bath treatment at an initial concentration that removed S. sciaenicola from mulloway gills did not remove C. glandulosum.

A survey of the methods being employed to determine antimicrobial susceptibility of bacteria associated with aquaculture was performed on behalf of the Permanent Advisory Network for Diseases in Aquaculture. Thirty-two laboratories in 18 countries responded and 25 reported the breakpoints they used for disc diffusion assays applied to Group 1, non-fastidious organisms isolated from finfish. A total of 117 breakpoints were reported for assays in which the disc contents were those specified by the current standard protocols. Data on the source of these breakpoints and the confidence the laboratories had in them are presented. Overall there was a considerable variation in the breakpoints employed by different laboratories and this variation is discussed in terms of the inter-laboratory precision that can be expected from the application of disc diffusion protocols. This paper discusses the possible clinical significance of the variations in the breakpoints and, where there are available data, the extent to which those in use are consistent with breakpoints suggested by other approaches. The data presented in this paper represent a starting point for the movement towards harmonising breakpoints used in association with the standard disc diffusion protocols that have been proposed for susceptibility testing of bacteria associated with fish diseases.

There are large differences between countries in the rate of growth and development of marine aquaculture, and also in the sophistication and complexity of its regulation, control and monitoring procedures. The potentially deleterious impacts of aquaculture are widely documented in the literature [J. Appl. Ichthyol. 17 (2001) 181; Fernandes, T.F., Eleftheriou, A., Ackefors, H., Eleftheriou, M., Ervik, A., Sanchez-Mata, A., Scanlon, T., White, P., Cochrane, S., Pearson, T.H., Miller, K.L., Read, P.A., 2002. The Management of the Environmental Impacts of Aquaculture. Scottish Executive, Aberdeen, UK, 88 pp.]. It is widely accepted that such impacts would be minimised or negated by the adoption of appropriate culturing procedures and environmental safeguards including regulatory, control and monitoring procedures [Nature Conservancy Council (NCC), 1989. Fish Farming and the Safeguard of the Natural Marine Environment of Scotland. Nature Conservancy Council, Peterborough, England, 136 pp.; Codling, I.D., Doughty, R., Henderson, A., Naismith, I., 1995. Strategies for Monitoring Sediments and Fauna Around Cage Fish Farms. Marlow, UK: Scotland and Northern Ireland Forum for Environmental Research (SNIFFER), Report No. SR 4018, 78 pp.; GESAMP (IMO/FAO/UNESCO-IOC/WMO/WHO/IAEA/UN/UNEP Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection), 1996. Monitoring the ecological effects of coastal aquaculture wastes. Scientific aspects of marine environmental protection. Rome, Italy: Rep. Stud. GESAMP No. 57, 38 pp.; GESAMP (IMO/FAO/UNESCO-IOC/WMO/WHO/IAEA/UN/UNEP Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection), 2001. Planning and management for sustainable coastal aquaculture development. Rome, Italy: Rep. Stud. GESAMP No. 68, 90 pp.]. It is essential that such safeguards are formulated from the best available science and technology and from the best available experience and expertise. In this context, there are lessons to be learned from the strategy and regulatory framework for the regulation, control and monitoring of environmental impacts of marine aquaculture within the European Union (EU). This paper identifies some of the main issues relevant to the management of environmental impacts of marine aquaculture; reviews EU and international policy and regulations in this context and provides one example of a strategy for the management of the environmental impacts of marine aquaculture by reference to the marine aquaculture industry in Scotland. In conclusion, it examines a number of current, key environmental concerns pertaining to the impact and regulation of marine aquaculture, which whilst being the subject of divergent views, are pivotal to the development of the industry. Recommendations for systems, procedures and research to address these concerns are identified. The paper is primarily concerned with marine finfish culture, although brief reference is made to shellfish culture. The control of diseases of finfish and shellfish is outside the scope of the paper, although brief consideration is given to current concerns relating to sea lice (predominantly Lepeophtheirus salmonis) infestations in salmonids.

Studies on the nutritional requirements of fingerlings and juvenile fish (a few grams to 50 g of body weight) were initiated in the 1960s. The main nutritional requirements of certain freshwater fish were clarified during the first half of the 1980s. Since the early 1990s, the focus has been on marine fish larvae. It has been thought that the definite nutritional requirements of the young and adult stages of fish could be directly applied to the larvae. Many differences, however, have been observed in the nutritional requirements of larval marine finfish (less than 1 g) using live foods. In this paper, the characteristics of nutritional requirements during the early life stage of marine finfish are presented together with the development of live food in Japan. The following aspects are covered in this paper: 1. Taurine requirements of juvenile Japanese flounder, Paralichthys olivaceus; 2. Negative effects of vitamins A and D and their related compounds on larval Japanese flounder, P. olivaceus; 3. Nutritional effects of docosahexaenoic and eicosapentaenoic acids on behavior of larval yellowtail, Seriola quinqueradiata; 4. Enrichment material developed for certain live foods; 5. New types of a microparticle diet developed for larval red sea bream, Pagrus major.

In order to make decisions regarding when to harvest cultured shrimp, short-term forecasts of future growth must be compared with expected future costs and changes in the value of the shrimp harvested. As with most agricultural products, researchers and business professionals collect and maintain data on the various factors that influence growth. Though many general fixed relationships between, say salinity, temperature, time and turbidity are known, exactly how these affect a particular crop changes from year to year. Vitality of the stock, unmeasured characteristics of the pond, and other factors which vary over time have a significant affect on the yield of a harvest. Consequently, to make reasonable short-term forecasts, forecasting models must include both the general factors gathered from past experience and crop specific variations from these overall effects. This paper presents a method of obtaining such a forecasting equation using a general mixed model setup currently available in many computer packages. These general formulas are illustrated with a real life example. SAS code necessary to implement the analysis is also included. The paper concludes by presenting a general equation for short-term forecasts using the estimates obtained from a SAS analysis.

Paper chromatography was used to determine the capacity of wild Penaeus indicus digestive gland homogenates to hydrolyse 27 carbohydrates containing a variety of bond types. Whereas all α-1 → 4 and α-1 → 1 bond oligosaccharides (including disaccharides and Schardinger β-dextrin) and α-D-glucans like starch, glycogen and pullulan were hydrolysed to a great extent, the same bond in the α-D-galacturonan pectin only underwent limited hydrolysis while that in the heteroglycan alginic acid was not broken down at all. β-type glycosidic bonds tended to be resistant to enzymatic degradation. The β-2 → 1 bond in inulin and the β-2 → 6 bond in levan as well as the β-1 → 4 bond in β-D glucans like cellulose, xylan, chitin and agar were not hydrolysed. However, β-D-glucans with β-1 → 3 linear bonds like laminarin and laminaritol were hydrolysed. There was also some breakdown of salacin. Among simple carbohydrates, chitin building units (β-1 → 4 bonds) were not hydrolysed indicating the absence of endogenous and exogenous (microbial) chitobiase. In contrast, the same bond type in cellobiose and lactose as well as the β-2 → 1 bond in sucrose were hydrolysed. These results indicate the absence of β-1 → 4 glucanases but the presence of significant activities of β-disaccharases except chitobiase. The carbohydrate component of any diet formulation for shrimp should therefore be assessed in light of these findings. The simple paper chromatography procedure employed requires minimum investment and can be used by any small scale shrimp feed manufacturing unit or shrimp farm.

Four-month-old juvenile Tridacna gigas were placed in plastic bags and exposed to pure oxygen in combination with four treatments: seawater, seawater+antibiotic, wet paper toweling (below clams), wet paper toweling (above and below clams). The only treatment which had high survival (98.5%) after 30 h application was seawater+antibiotic (streptomycin sulphate, 25 ppm). Desiccation as a cause of death was apparent, especially in smaller size classes in other treatments. A shipment of 5000 5.5-month T. gigas juveniles was sent to Fiji Fisheries. Despite a 40-h period from packing to reimmersing clams, survival was 64% after 4 days of reimmersion in the quarantine system in Fiji.

The paper was prepared as background material for a symposium discussion of breeding plans for aquaculture production. Although there is an extensive literature on the theory of breeding plans and their application to livestock and plant production, the question has received little attention among aquacultural geneticists. The paper summarizes the basic theory underlying the development of breeding plans, discusses the genetic basis for evaluating selection response, considers the selection response expected for a limited set of alternative breeding plans, and briefly examines the relative effects of each type of plan on rates of inbreeding.

appears to be stable and hardly influenced by management factors, such as types of fish stocked, total stocking rate (until a certain threshold is reached), proportion of different fish or type of manure used.” Given this consistency, we might expect that the variance about the mean of his replicates (not published) was small. In that case, our results, which were quite variable, but which included yields significantly higher than his published mean, as well as an analysis of causes of the variation, would be of interest. From such variation and analysis come the potential of increased yield, the subject of our paper and reflected in the title. We do concede that our data were from tanks, not ponds, and were for 2-month, rather than 6-month trials. The scope of the study was explained clearly in the paper. Incidentally, the 2 tank results in question were from whole experiments, not from selected portions. The fastest 2-week interval of growth from any tank was 8.8 g/m’/d.

The intensification of Scottish salmon farming has been associated with increasing demands for the monitoring and safeguarding of farmed salmon welfare. Continued growth of farm productivity, while avoiding adverse effects on salmon welfare, will require the development of effective welfare assessment tools.This paper reports on a survey of the Scottish salmon farming industry, which was conducted to understand current salmon welfare concerns and priorities for research. As part of a broader aim for further developing tools for on-farm salmon welfare assessment, a total of 61 individuals working in the Scottish salmon farming industry took part. This survey intentionally focused on industry stakeholders to provide insights into current practices and challenges associated with monitoring and assessing salmon welfare. Participants were recruited through authors’ industry contacts, online advertisements, and searches of company websites. In terms of production stages, survey participants believed that the seawater rearing stage is a major area of concern, largely due to thechallenges presented by sea lice. Gill health and environmental challenges, mainly relating to water quality, were two other highly ranked welfare concerns. Methods to monitor salmon welfare during husbandry practices, where disturbances and contact with the salmon is unavoidable (particularly during crowding, grading, andinterventions), were emphasised as a priority. Although these were identified as the major concerns, the survey indicated that there are other significant welfare concerns specific to each production stage that also require consideration.Participants highlighted non-invasive, remote, and animal-based welfare measures as important areas for further development for on-farm welfare assessments. Behavioural measures were identified as having the potential to make a major contribution in this context. This survey presents the first collection of opinions from professionals employed across the Scottish salmon farming industry regarding the current overall state of farmed salmon welfare. This study upholds the importance of using an integrated approach to welfare assessments, and that behavioural measures could play an important role in ensuring these assessments benefit both salmon welfare and farm productivity.

Fishery and aquaculture sectors use blockchains to enhance traceability and transparency in value chains and to fight illegal, unreported, and unregulated fishing. The aim of this paper is to provide the current status and future prospects of blockchain application in worldwide fisheries and aquaculture. A literature review was conducted using blockchain and global value chain frameworks. Results indicate that generally, the use of blockchain is vertically driven by the requirements of markets and business competitiveness. The majority of the blockchain use cases are for traceability and storytelling, and to a lesser extent for payments or incentives. Moreover, there has been limited use cases of blockchain at horizontal level, such as decentralized finance (de-fi), enabling fishers to gain capital access and entering global markets. Overall, enhancing the adoption of blockchain should address suitability, incentives, and trust factors in using blockchain. As future prospects, projects in fishery and aquaculture could better utilize the full potential of blockchains by (1) incorporating financing, capital, and insurance through de-fi solutions, (2) providing tangible incentives, and (3) using automation such as Internet-of-Things (IoT) in data collection to improve quality and trust in data.

A marine parasite on an anadromous host has a unique transmission challenge. It must infect a subsequent generation (or an alternate host species) prior to its current host's entry into freshwater, where the parasite (and often its host) will die. The salmon louse, a salmonidspecific parasite, faces just such a problem, and we would expect this species to have evolved a strategy to maximize transmission during the limited window of opportunity when incoming adults and outmigrating juveniles (or alternate hosts) are present in an area simultaneously. In their 2007paper “A proposed life historystrategy for the salmon louse, Lepeophtheirus salmonis in the subarctic Pacific”, Beamish et al. (hereafter BEA) hypothesize a strategy enabling sea lice to solve this problem. The data in this paper are interesting in showing that adult Pacific salmon carry salmon lice into the coastal environment during their migration and overlap with juveniles in the late summer (August). Although these data confirm anecdotal evidence of the presence of sea lice on adult salmon in the marine coastal environment, something known to all fishermen, we argue that BEA's hypothesis is fundamentally flawed and their paper invites misleading citation. BEA use incorrect terminology and vague definitions, and omit important literature while arriving at highly speculative and, in our opinion, inappropriate conclusions.

The archeospore is an asexual reproduction strategy for some red algae, including Pyropia. Since cultivation of Pyropia yields important economic returns, whether or not it forms archeospores that can reseed nets becomes a key feature for this commercial seaweed. In this paper, desiccation, diurnal temperature changes and irradiance were tested for their effects on archeospore production by Pyropia yezoensis Ueda. Our results first showed that 2–3 h of daily, rhythmic desiccation and diurnal temperature changes strongly induced archeospore production, especially for the group with an increased temperature during the light period and a decreased temperature during the dark. The results also confirmed that a short photoperiod and a relatively higher light intensity benefitted the production of archeospores.

Aquaculture farms' efficiency may be different across regions due to spatial variation in their production environment. Thus, if efficiency is measured and compared without accounting for regional differences in the production environment, it may lead to a biased evaluation of efficiency and correspondingly erroneous policy suggestions. This paper uses the meta-frontier approach to compare efficiency among a sample of 625 farms producing pangas and tilapia located in different regions of Bangladesh and exposed to different production environments. Furthermore, Spearman correlation is employed to identify factors, such as sources of water supply, water and soil quality that influence efficiency. The results suggest that efficiency varies significantly across regions due to variation in the production environment, the individual producers' ability to manage inputs and selection of species depending on local environmental conditions. This study implies that policymakers should take into account variation of the production environment between regions and the performance of specific species within these environments when making plans for future expansion of aquaculture production to use the resources most efficiently.

Certification and third party accreditation schemes are examples of private-social partnerships that make up a form of hybrid governance. We argue that hybrid governance is changing the way traditional governance is being utilised. In this paper we examine the rise of third party certification and the challenges these governance arrangements bring to traditional governance. We examine this through analysis of the Aquaculture Stewardship Council (ASC) and the application of the ASC standard in salmonid aquaculture in Tasmania, Australia. This example emphasises that market and consumer engagement is challenging government policies and posing key questions over the role of traditional state practice in the evaluation of sustainable aquaculture. A key factor, however, underpinning such engagement is trust. Thus ASC certification is likely to be a necessary, but not a sufficient, condition supporting the granting of social licence to operate.

Control of reproduction is one of the key issues to extend tilapia aquaculture. In most fish species, reproduction is a rhythmic process which ensures that reproduction timing matches the most favorable environmental conditions to maximize the survival of offspring. Although the existence of daily spawning rhythms has been reported for a number of fish species, the daily rhythms in neuroendocrine factors along the BPG (brain-pituitary-gonadal) axis remains mostly unknown. The objective of this paper was to investigate the existence of daily rhythms in BPG gene expression and plasma sex steroids in tilapia (Oreochromis niloticus). To this end, 36 males and 36 females were kept in separate tanks at 29 ± 0.5 °C and in a 12 h:12 h light/dark cycle. After 4 weeks of acclimation, male and female tilapia were mixed into six groups at a female:male ratio of 6:6. Two weeks later, fish were anesthetized and sampled every 4 h during a 24-hour cycle, and blood, brain, pituitary, gonad and eggs were collected for later analyses. The expression levels of the genes from the brain (gnrh1, gnrh2, gnrh3, kiss2, gnih), pituitary (fshβ and lhβ), gonad (star, cyp11a, cyp17, cyp19a1a and amh) and eggs (zp3b and fyna) were analyzed by qPCR. ELISA was used to analyze testosterone and estradiol in male and female plasma, respectively, and maturation-inducing hormone (MIH) in plasma in both sexes. The results revealed timely-coordinated daily rhythms along the BPG axis of tilapia. The expression of the brain genes showed that their acrophase was distributed throughout the LD cycle. However, a coordinated and harmonious pattern of daily rhythms appeared on the following levels of the BPG axis. The peaks in expression of the pituitary genes were reached at night, while the gonadal genes and plasma sex steroids peaked in the light phase. These findings can be useful for improving breeding protocols for tilapia aquaculture and for defining optimum timing for reproduction in captivity.

Monitoring an aquatic environment in aquaculture is usually carried out by controlling its physicochemical and biological parameters. The global state of the process is evaluated though the individual conditions shown in each parameter. However, the correlation structure in the data, caused by interdependence between these parameters, provides relevant information which must be controlled. Thus, the complex structure of the data requires a multivariate control method to explore both the individual and interactive effects of the environmental parameters. To achieve this goal, this paper presents a statistical method based on a Multivariate Exponentially Moving Average (MEWMA) chart to monitor the multivariate structure of an aquatic environment in aquaculture, especially in a crop of tilapia in Mozambique. The results show that the adjusted MEWMA chart is more consistent when controlling the conformity and stability of environmental parameters. Therefore, it can be considered an efficient statistical method to monitor an aquatic environment in aquaculture.

Recently, Vibrio harveyi has emerged as an important pathogenic disease with a high mortality rate (50%–70%) in Chinese tongue sole. The aim of this study was to estimate genetic parameters for resistance to V. harveyi in Chinese tongue sole and to evaluate the genetic correlation between resistance and growth traits (i.e. body weight and total length) (involving 50 full-sib families and 8547 individuals). Longitudinal linear models and cross-sectional threshold models were fitted by using different trait definitions (binary and categorical). After a 14-day test, the overall challenge test survival was 57.86% (ranging from 9.30% to 94.30% in families). The heritabilities of survival were ranging from 0.11 to 0.28, estimates obtained by linear models were higher than threshold models. The genetic correlations between resistance (binary and categorical traits) and two growth traits were moderately positive (0.27–0.51). Very high Pearson and Spearman correlations (0.99 to 1) of full-sib family EBVs between different models were all close to unity which might reveal the similar predictive ability of the four models. The favourable heritabilities and moderate positive genetic correlations indicate that joint genetic improvement of vibriosis resistance and growth performance would be feasible. Statement of relevance This paper offers guidelines to disease-resistance selective breeding strategies in Chinese tongue sole.

The EU aquaculture industry is a politically prioritized industry as shown in the EU's Farm to Fork Strategy. The political objectives include biological, economic and social sustainability of the industry. However, while a lot of attention has been paid to the economic importance and environmental impact from the aquaculture sector, there has been less focus on the social dimension. This paper contributes to the development of the social dimension by providing a baseline of the employment structure in the EU aquaculture sector. This is done by producing the first coherent overview of the employment in the sector presenting demographic information on gender, age, education and nationality. Data are further provided by country, by production technology, and by sector (marine, fresh water, shellfish). The results show that the sector is dominated by employees that are citizens of the same country as they are employed, are male, are between 40 and 64 years old, and have a low to medium level of education.

Feed is the most main expenditure in outdoor intensive culture system. The improvement of feeding efficiency has great significance for increasing production and reducing costs. Presently, with the development of precision agriculture, automatic adjustments of the feeding amount according to the demands of the fish has become a developing trend. The objective of this paper was to develop an automatic feeding decision-making system based on the water quality parameters to solve the problem of inefficiency in artificial feeding control. In this study, we proposed an effective control method using adaptive neural fuzzy inference system (ANFIS) to achieve this purpose. First, two input variables (dissolved oxygen saturation [DO]; temperature [T]) and one output variable (feeding percent [FP]) were selected and defined. Second, the model of the linguistic variables and the optimal fuzzy rule base were obtained by the training and learning by utilization of hybrid learning methods. Finally, an ANFIS controller for on-demand feeding was developed and the performance was compared with Fuzzy logic control (FLC) and artificial control (AC) by the Nash-Sutcliffe efficiency coefficient (NS), the root mean squared error (RMSE), and fish growth parameters. The results indicated that the NS and RMSE of the ANFIS model were 0.8539 and 0.0541, respectively, and were better for forecasting feeding decisions compared with the FLC and AC methods. Compared with the AC, there was no significant differences in promoting fish growth (P > 0.05), whereas the feed conversion rate (FCR) was reduced by14.35%. In addition, the mean of ammonia nitrogen concentration decreased by 22.59%, and the mean of turbidity increased 5.5 cm to 28.9 cm, reducing eutrophication and pollution of water in pond. Therefore, applying those approaches based on ANFIS control to the feeding decision system in outdoor intensive culturing is flexible and effective, and has potential for the design of fine feeding equipment and to guide this practice for other species.

Sustainable food products have become significantly more important over the last decades. One example is the constant growth in the market for organic food. However, market shares for sustainable aquaculture products remain small. Parallel to emerging markets for sustainable foods, consumers' interest in the geographical origin, in particular domestic and local food production evolved. The aim of this paper was to elicit target groups for fish from sustainable aquaculture and their preferences for different countries of origin. Choice experiments and structured interviews were conducted with 447 German consumers of fish to analyze heterogeneous consumer groups. The results of latent class modelling yielded five target groups. One consumer segment (19%) was predominantly considering sustainability labels and claims on production criteria, i.e. ‘production in natural ponds’ and ‘sustainably produced’. The largest consumer segment (39%) placed highest importance on the COO while sustainability labels and claims had a positive but much weaker impact. Yet, another consumer segment (20%) gave the country of origin priority over all other attributes. Two more classes based their choice primarily on price, with one class preferring premium prices and the other class low prices. Marketers of sustainable aquaculture products are advised to source products from countries of origin that consumers prefer, and prominently declare the country of origin. For reaching new target groups, certified sustainable producers should not only rely on their label. It is recommended to focus on production criteria of consumer interest, for example the production in natural ponds, and state these on the product package.

Acute hepatopancreatic necrosis disease (AHPND) is an emerging disease that has caused mass mortality in shrimp in many countries in Asia and South America. A new strain of Vibrio parahaemolyticus (VpAHPND), carrying one or more extrachromosomal ~70 kbp plasmids that encode homologues of the Photorhabdus insect-related (Pir) binary toxins (PirAvp and PirBvp) is the causative agent of AHPND. Bioassay challenges using immersion, reverse gavage and per os (feeding) treatments have been shown to induce the pathology characteristics of AHPND in experimentally infected shrimp. Moreover, a number of polymerase chain reaction (PCR) methods have been found to facilitate early detection of the disease. However, non-V. parahaemolyticus species close to Vibrio harveyi, Vibrio owensii and Vibrio campbellii have recently been identified as carrying pVA1-like plasmids, signifying that these plasmids are capable of being transmitted to different Vibrio species. AHPND is thus a threat and a serious concern for the aquaculture industry. Against this background, this paper presents an overview of experimental methodologies and diagnostic procedures for AHPND. It also includes fundamental findings related to the disease as guidelines which may be useful for further experimental work on AHPND and other similar shrimp diseases.

Red sea bream iridovirus (RSIV) is an emerging viral pathogen having significant socio-economic and environmental impacts on marine and brackish aquaculture systems. The study documents certain interesting findings of an RSIV disease outbreak that caused 50% cumulative mortality among cage farmed Asian sea bass in India. The confirmatory diagnosis was made based on internationally approved protocols. The affected fish showed splenomegaly, anaemia, and abnormally enlarged cells within the spleen, liver, kidney, and brain. The consistent presence of two fish pathogens, viz., Vibrio alginolyticus and Vibrio fluvialis, in the liver, along with characteristic vibrio-induced pathologies were noted, indicating the possible role of these bacterial pathogens in RSIV pathogenesis during the outbreak. More strikingly, the surviving fish were found to carry the virus even after two months post-outbreak, warranting future investigations on the carrier status of RSIV survivors. Transmission electron microscopy in the survivors demonstrated atypical virus particles within the degenerated cells of the vital organs, suggesting the role of host immune response in preventing the maturation of RSIV particles in the survivors. Phylogram based on MCP and ATPase genes demonstrated the spread of the same RSIV clone across different countries, regardless of the fish species. Results also revealed the presence of two RSIV subtypes. Both subtypes were mainly distributed in marine demersal fishes of Asian countries. Presently, subtype 2 is the most frequently reported one. Subtype 1 revealed higher genetic diversity with a wider geographical spread and host range. Molecular analyses revealed that MCP and ATPase genes could be targeted in RSIV subtyping, with MCP as a better candidate. A purifying selection was observed on the MCP gene that can be applied for diagnostic protocols. In short, the study generates certain thought-provoking insights on RSIV through the analyses of a recent outbreak along with the genetic and epizootiological data of global strains. Further, the paper also forms the first report on the presence of RSIV in surviving fish post-disease outbreak in the absence of clinical signs. Altogether, the results highlight the necessity of strengthening quarantine and RSIV diagnostic measures to have sustainable aquaculture practices.

9 pages, 8 figures, Marine aquaculture takes advantage of marine ecosystem services to produce goods that can be relevant from a food security point of view. However, this activity is subject to multiple stressors as the ones exerted by global climate change. Local stressed conditions due to environmental drivers may be exacerbated by the COVID19 pandemic crisis. In this paper we analyze the pre-COVID-19 situation in two Spanish regions with the highest aquaculture production, Galicia and the Valencian Community. The incidence of storms, heat waves and mussel farming closure were analyzed, and surveys were used to define the perception of producers in terms of economic problems derived from COVID-19 and synergistic environmental concerns. Also the temporal trend of mussel production was analyzed. Spanish marine aquaculture has been intensively subjected to climatic stressors that made it more vulnerable to COVID-19, showing some weakness in terms of production as can be seen in mussel production and fresh consumption. Anyway, extensive aquaculture and aquaculture developed by Integrated Multi-Trophic Aquaculture (IMTA) was reported as somewhat more resilient to the impact of COVID-19. In order to ensure the environmental and economic sustainability of marine aquaculture - under a future uncertain pandemic scenario – our outcomes underline the need for more resilient adaptation programs and recovery plans taking into account the climate change effects, M.C.M.’s research activity was supported by the European Union’s Horizon 2020 Research and Innovation pro- gramme under the Marie Skłodowska-Curie Action (Grant agreement no. 835589, MIRROR Project)

This paper reports the first benchmarking of smallholder tilapia farming practices in rural northern Zambia, measuring fish growth, feed utilization and water quality parameters, using a participatory action research approach. The effects of three different feeding regimes that are currently used in smallholder farming systems in northern Zambia on the growth of the native tilapia, Oreochromis macrochir, were tested with 15 farmers (40% female), each having three ponds (one pond per feed treatment per farmer = 45 in total), over eight months in 2016–2017. The three feed treatments included: (1) formulated feed only comprising maize and soybean; (2) goat manure only; and (3) formulated feed and manure together. Three hundred (300) O. macrochir mixed-sex fingerlings, 0.5 ± 0.1 g average weight, were stocked in each pond. Water quality (pH, dissolved oxygen, and water temperature and transparency) was measured monthly, as was fish growth in each pond by randomly sampling thirty (30) fish and taking individual weights and lengths. Results showed that the water quality parameters were broadly similar in the different feed treatments over the eight-month experiment period, except for the water transparency values that were higher in the feed only treatment when compared to the other two treatments at months four through eight. Means for survival rate, weight gain, specific growth rate, total amount of fish harvested, and yield were all higher for the feed and manure together treatment than the other two feed treatments at the end of the experiment. A linear mixed-effects regression analysis that controlled for several fixed effects and included pond as a random effect found that the feed and manure together treatment increased fish growth by 10.8 ± 3.7 g at month eight compared to the manure only treatment. The analysis also found a negative effect on fish growth (−9.4 ± 3.8 g) in ponds that used the feed only treatment. The pond effect accounted for 10.1% of the total variance in the data at month eight. Future research and development efforts in Zambia should examine more closely the factors that influence fish growth and that make up the pond effect to determine which innovations and better management practices could help smallholder farmers increase the productivity of their ponds.

This paper analyses the antioxidant enzymes response of Mytilus galloprovincialis exposed to a tar mixture during a laboratory assay. These tar mixtures are generally used in the cleaning and waterproofing of the wooden rafts used in mussel culture, and are characterized by their high content in PAHs and transition metals. The punctual spillage of these mixtures around the rafts could cause mussel stress, affecting culture sustainability and product quality for human consumption. The analysis of kinetic parameters and specific activity of the enzymes analysed revealed important tissue differences, which can be summarized as high affinity for reactive species in gills, and high antioxidant efficiency in digestive gland and mantle tissue. Furthermore, the analysis of variance demonstrates dose- and time-dependent response of most enzymes to tar exposure, as well as influence of the dose-time interaction. Antioxidative metabolism of gills constitutes an early response against pollution-stimulated ROS production and is mainly mediated by SOD and CAT activities. While antioxidant defence of digestive gland and mantle is carried out mainly by peroxidases and glyoxalases. These results suggest the necessity of taking into account the integrated antioxidant response of different organs from bioindicator species in toxicological studies. Multivariate analysis of all data obtained corroborates the antioxidant tissular differences, and highlights the activities SOD of gills, GST of digestive gland and Se-GPX of mantle from mussels as suitable biomarkers of PAHs pollution. In the natural environment, the relationship of these enzyme activities, independently of their seasonal or physiologic variation, discriminates between different PAHs and Pb concentrations accumulated in mussels, validating their utility in the assessment of aquaculture areas quality. Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG

Several papers have reported on the development of antibiotic resistance and implications for human medicine but fewer deal with environmental impacts of antibiotic use. Marine sea cage aquaculture ...