Integrated Multi-trophic Aquaculture Research Articles

THE TECHNOLOGICAL WATER NITROGEN COMPOUNDS DYNAMICS IN THE EXPERIMENTAL PONDS, INLET AND OUTLET CHANNELS

This study aims to identify proper solutions that can improve the sustainability of cyprinids pond aquaculture in terms of nitrogen releases to the environment. Therefore, two experimental variants, based on polyculture, respectively integrated multi-trophic aquaculture (IMTA) concept were tested, as follows: PCP – polyculture of common carp (CC) + grass carp (GC) + bighead carp (BC) + silver carp (SC); CP-PP – net divided pond with CC monoculture in CP part and CC+GC+BC+SC polyculture in PP part. In order to determine the nitrogen accumulation at the pond level, samples of water, sediments, fish meat and reed were analyzed. The results indicate that the highest nitrogen compounds concentrations in pond water were registered at CP part of CP-PP pond. However, the nitrogen concentration in pond effluents was significant higher in case of CP-PP pond, compared with PCP pond. The nitrogen compounds concentration of sediments registered the highest values in the ponds outlet area. Also, CP-PP pond recorded higher nitrogen concentration in sediments, compared with PCP pond. The CC registered the highest nitrogen compounds concentration in case of PP pond area, followed by CP pond area and PCP pond. Not significant correlation was found between reed and pond water/ fish meat/ sediments in terms of nitrogen compounds concentration. It can be concluded that the CP-PP pond feeding management, together with the tested technical solution (pond dividing) generated better water conditioning performances.

A New Look for the Red Macroalga Palmaria palmata: A Seafood with Polar Lipids Rich in EPA and with Antioxidant Properties.

Palmaria palmata is an edible red macroalga widely used for human consumption and valued for its high protein value. Despite its low total lipid content, it is rich in eicosapentaenoic acid (EPA). This seaweed has been scarcely explored with regard to its lipid composition. The polar lipids of seaweeds are nowadays recognized as important phytochemicals contributing to their add value valorization and providing support for claims of potential health benefits. The present study aimed to disclose the polar lipid profile of P. palmata, farmed in an integrated multi-trophic aquaculture (IMTA) through modern lipidomic approaches using high-resolution LC-MS and MS/MS and to screen for the antioxidant properties of this red macroalga. A total of 143 molecular species of lipids were identified, belonging to several classes of polar lipids, such as glycolipids, phospholipids, and betaine lipids. It is noteworthy that the most abundant lipid species in each class were esterified with eicosapentaenoic acid (EPA), accounting for more than 50% of the lipid content. The polar lipid extract rich in EPA showed antioxidant activity with an inhibition concentration (IC) of IC30 = 171 ± 19.8 µg/mL for α,α-diphenyl-β-picrylhydrazyl radical (DPPH●) and IC50 = 26.2 ± 0.1 µg/mL for 2,20-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS●+). Overall, this study highlights that P. palmata farmed in an IMTA framework can be a sustainable source of beneficial lipids with antioxidant activity. Moreover, this red macroalga can be exploited for future applications as a source of lipids rich in EPA for food and feed, nutraceuticals, and cosmetics.

The budget of nitrogen in the grow‐out of the Amazon river prawn ( Macrobrachium amazonicum Heller) and tambaqui ( Colossoma macropomum Cuvier) farmed in monoculture and in integrated multitrophic aquaculture systems

This work determined the nitrogen inputs, outputs and accumulation in compartments of stagnant earthen ponds for the monoculture and integrated multi-trophic aquaculture (IMTA) of the Amazon river prawn (Macrobrachium amazonicum) and tambaqui (Colossoma macropomum), using recycled hypereutrophic water. A completely randomized experiment was designed with four treatments and three replications: PM–monoculture with 30 prawns/m2, FM - monoculture with 3 fish/m2, IMTA - polyculture with 30 prawns/m2 and 30 fish/m2 free, POLY-CAGE - polyculture with 30 prawns/m2 free and 40 fish/m3 in net-cages. Animals, rain, water, feed, soil, gas, accumulated sludge, and suspended sediments were collected throughout the experiment to determine their nitrogen contents and to calculate the nitrogen budget. Results showed that much of the nitrogen available escapes to atmosphere as N2 (~40%–56%) after denitrification or accumulated within bottom sludge (~14%–42%). The remaining nitrogen was converted in animal biomass (~5%–21%) or was discharged to receiving waterbodies in the outlet water (~11%–13%). Feed management appeared to influence the major biological processes in the aquatic nitrogen cycle, such as photosynthesis and denitrification. The fish-prawn IMTA systems converted approximately 53%–75% of feed nitrogen into harvestable products, which is more efficient than the 19%–46% of feed nitrogen converted in the monocultures. However, a large amount of nitrogen is accumulated in the pond bottom in all systems. An increased prawn density or the addition of a mud-feeder species to the culture may enhance the incorporation of this material in harvested biomass, improving the efficiency of the systems.

A discounted cash-flow analysis of salmon monoculture and Integrated Multi-Trophic Aquaculture in eastern Canada

We assess the financial performance of an Atlantic salmon (Salmo salar) monoculture versus an Atlantic salmon, blue mussel (Mytilus edulis), and sugar kelp (Saccharina latissima) Integrated Multi-Trophic Aquaculture (IMTA) operation. Using updated methods and models, we improve on earlier studies of IMTA economics. A discounted cash-flow analysis was used to assess the profitability of hypothetical monoculture and IMTA operations over a 10-year period in the Bay of Fundy, New Brunswick, Canada. The IMTA operation was more profitable, even when no price premium was included for its products. A 10% price premium for IMTA salmon and mussels resulted in a substantially higher net present value for the IMTA operation than for salmon monoculture. However, uncertainty related to IMTA’s financial and environmental performance, as well as IMTA’s increased operational complexity, may be barriers to IMTA adoption in Canada at present. As a result, it is likely that IMTA must generate substantially greater profits than salmon monoculture to stimulate investment. Alternatively, declining salmon production in recent years may encourage IMTA adoption in the future since it can provide crop diversification and economic stability benefits. IMTA research may benefit from alternative assessment methods such as the real options approach that explicitly incorporate uncertainty.

Cumulative impact of long-term intensive mariculture on total and active bacterial communities in the core sediments of the Ailian Bay, North China.

The exponential growth of off-shore mariculture worldwide over the last 20 years has had significant impact on coastal sediment biogeochemistry. However, there are no long-term records of the cumulative impacts of mariculture on the benthic bacterial community. Here, total (DNA) and active (RNA) bacterial community compositions were characterized using MiSeq sequencing of 16S rRNA gene in four core sediments of the Ailian Bay, one of the typical intensive mariculture areas in China with more than fifty-year history of kelp and scallop cultivation. The γ-Proteobacteria, δ-Proteobacteria, Acidobacteria and Acitinobacteria were more abundant in the total bacterial communities, while β-Proteobacteria, Anaerolineae, Clostridia, Spirochaetes and Cyanobacteria were enriched in the active bacterial communities. Significant differences were observed between total and active benthic bacterial communities. The influences of different mariculture modes on the total bacterial communities were more significant than those on the active bacterial communities. Only limited groups of the total bacterial communities were significant influenced by the cumulative effects of the long-term mariculture. The bacterial genera with the function in the sulfide cycling and organic consumption were enriched in the total bacterial population of the integrated multi-trophic aquaculture (IMTA) areas. The variations of both total and active bacterial communities were significantly influenced by grain sizes, total organic carbon and nutrients. Both total and active bacterial communities exhibited a slightly stronger response to environmental factors than to spatial (distance) factors. The effects of mutualism might dominate the total and active bacterial networks in the Ailian Bay. The present study demonstrated that the cumulative influences of the long-term and intensive IMTA mariculture on total benthic bacterial communities in the sub-surface sediments of the Ailian Bay were stronger than those on the active benthic bacterial communities, which provided some insights into the potential ecological roles of specific taxa in the sediments of the IMTA ecosystems.

Understanding the individual role of fish, oyster, phytoplankton and macroalgae in the ecology of integrated production in earthen ponds

In order to demonstrate that IMTA can be profitable and a good alternative to regular semi-intensive fish mariculture production in earthen ponds three different production treatments with distinct combinations of trophic levels were designed: (i) a combination of fish, filter feeders, phytoplankton and macroalgae, (ii) fish, filter feeders and phytoplankton and (iii) fish, phytoplankton and macroalgae, to evaluate the role of each trophic level within an Integrated Multi-Trophic Aquaculture system (IMTA). Each treatment was carried out under semi-intensive conditions with two replicates, in a total of 6 earthen ponds of 500 m2 surface and depth of 1.5 m. The results showed that fish, oyster, phytoplankton and macroalgae integrated aquaculture is a healthy sustainable production system for mariculture in earthen ponds, providing much more fish supply compared with the other two treatments. Ponds with filter feeders had significantly lower turbidity (Nephelometric Formazin unit (FNU) of 13 in the morning and 17 in the afternoon) when compared to ponds without filter feeders (16 FNU in the morning and 20 FNU in the afternoon) with increased light penetration throughout water column (61 and 55 cm transparency in ponds with filter feeders compared to 51 cm in ponds without filter feeders) and consequently higher photosynthetic activity with significantly higher dissolved oxygen (5.4 mg L−1 in the morning and 6.7 mg L−1 in the afternoon in ponds with filter feeders compared to 5.3 mg L−1 in the morning and 6.4 mg L−1 in the afternoon in ponds without filter feeders) and carbon sequestration (0.50 and 0.53 mg L−1 8 h−1 in ponds with filter feeders and 0.43 mg L−1 8 h−1 in ponds without filter feeders). In the fish, filter feeder, phytoplanton and macroalgae IMTA treatment, phytoplankton played a crucial role because they increased DO levels, removed the excess of nutrients from animal excretion, and was used as food by the filter feeders. Almost as important is the presence of filter feeders since they control the density of the microalgae and particulate matter in the ponds contributing to a more constant level of DO and higher transparency of the water column. The increased transparency and pond fertilization by oyster excretion, resulted in higher proliferation of phytoplankton (chlorophyll a concentrations of 16.5 μg L−1 and 20.2 μg L−1 in ponds with filter feeder and 13.3 μg L−1 in ponds without filter feeder) with benefits not only for filter feeders themselves but also for the macroalgae. At the end there was higher water quality and higher savings (14% day−1) in the energy costs for pond aeration. Meagre, white seabream and flathead grey mullet enhance their performance in IMTA systems with the presence of filter feeders with food conversion rates (FCR) of 1.52 when compared with 2.46 in the regular semi-intensive system composed by fish, phytoplankton and macroalgae. Meagre grew significantly more in IMTA systems with controlled macroalgae while white seabream and flathead grey mullet enhance their performance in the presence of macroalgae. The results show that the fish, oyster, phytoplankton and macroalgae integrated production in earthen ponds is an improved system compared to the regular semi-intensive fish production. The enhanced water quality in these systems leads to improved fish performance and higher biomass production, and to reduction in the energy power used, contributing to greater profitability.

Integrated multitrophic aquaculture applied to shrimp rearing in a biofloc system

This study aimed to evaluate the performance of an integrated multitrophic aquaculture (IMTA) system applied to shrimp rearing in biofloc technology (BFT). The IMTA system consisted of shrimp (Litopenaeus vannamei) in a rearing tank (800 L), a tilapia (Oreochromis niloticus) rearing tank (90 L), and a hydroponic bench with 0.33 m2 of planting space for Sarcocornia ambigua culture. A submerged pump constantly pumped water from the shrimp tank to the tilapia tank. Then, by gravity, water flowed through the sarcocornia hydroponic bench and returned to the shrimp tank. The hydroponic bench had enough capacity for 32 plants. Shrimp, tilapia and sarcocornia stock densities were 312 shrimp m−3 (250 shrimps per 800 L tank), 445 tilapia m−3 (40 tilapias per 90 L tank), and 97 sarcocornia plants m−2 (32 plant per system), respectively. The same experimental units were used in the control system which only differed by the absence of sarcocornia. The initial weight was 4.09 ± 0.025 g, 1.16 ± 0.02 g and 1.17 ± 0.175 g for shrimp, fish and sarcocornia, respectively. Shrimps were fed according to the feed table, and the fishes were fed with 1% of fish biomass, stimulating tilapia to use biofloc as a food source. Results show no difference between shrimp and tilapia performance in either treatment. Only IMTA total yield (4.83 ± 0.19 kg m−3) was significantly higher than that in the control system (3.99 ± 0.045 kg m−3). Nitrate was higher in the control system (12.28 ± 1.27 mg L−1) compared to the IMTA system (9.38 ± 1.09 mg L−1).These results demonstrate a yield increase of up to 21.5% by multitrophic integration of L. vannamei, O. niloticus and S. ambigua in a biofloc system.

Testing the digestibility of seabream wastes in three candidates for integrated multi-trophic aquaculture: Grey mullet, sea urchin and sea cucumber

In this study the Integrated Multi-Trophic Aquaculture (IMTA) approach was examined at a gilthead seabream, Sparus aurata, farm located in the Eastern Mediterranean Sea. To achieve this, digestibility trials were conducted with three species representing different trophic levels, the grey mullet, Mugil cephalus, the sea urchin, Paracentrotus lividus, and the sea cucumber, Actinopyga bannwarthi using the particulate farm effluents as feed. To prepare the feeds, seabream faecal waste was collected by means of a large conical bag attached below a fish cage. The farm wastes were dried and pelleted after adding chromic oxide (indigestible marker) and alginate (binder). In the ensuing trials, the pellets were offered to the mullets, sea urchins and sea cucumbers. The faecal matter of the grey mullets was collected by stripping the fish, whereas for the sea urchins and sea cucumbers trials, faecal matter was collected by siphoning the faeces from the bottom of the tanks. The farm-waste feed and faeces of each of the tested species were analysed for chromic oxide, organic matter, protein, phosphorus, lipid, ash and energy content, and the apparent digestibility coefficient was calculated for each. The digestibility trial showed that mullets do not benefit nutritionally from the freshly deposited gilthead seabream wastes. However, both the sea urchins and sea cucumbers were able to obtain energy and nutrients from the gilthead seabream wastes, emphasising their potential as IMTA species. The sea cucumber expressed higher digestibility of the farm-waste feed than the sea urchin (11.7–45.9% and 3.8–16.3% respectively), which might be sufficient for productive growth based solely on a diet of “waste” material. These results demonstrate that IMTA systems based on detritivores in warm water locations allow to extract particulate wastes from commercial aquaculture farms and convert this to valuable biomass in the process.

Screening of Chaetomorpha linum Lipidic Extract as A New Potential Source of Bioactive Compounds.

Recent studies have shown that marine algae represent a great source of natural compounds with several properties. The lipidic extract of the seaweed Chaetomorpha linum (Chlorophyta, Cladophorales), one of the dominant species in the Mar Piccolo of Taranto (Mediterranean, Ionian Sea), revealed an antibacterial activity against Vibrio ordalii and Vibrio vulnificus, common pathogens in aquaculture, suggesting its potential employment to control fish and shellfish diseases due to vibriosis and to reduce the public health hazards related to antibiotic use in aquaculture. This extract showed also an antioxidant activity, corresponding to 170.960 ± 16. mmol Trolox equivalent/g (oxygen radical absorbance capacity assay—ORAC) and to 30.554 ± 2.30 mmol Trolox equivalent/g (Trolox equivalent antioxidant capacity assay—TEAC). The chemical characterization of the extract, performed by 1D and 2D NMR spectroscopy, highlighted the presence of free, saturated (SAFAs), unsaturated (UFAs) and polyunsaturated (PUFAs) fatty acids. The high content of ω-6 and ω-3 PUFAs confirmed also by gas chromatography indicates the potentiality of this algal species in the production of fortified food. The antibacterial activity seems related to the presence of linolenic acid present at high density, while the antioxidant activity could be likely ascribable to molecules such as carotenoids and chlorophylls (characterized also by thin-layer chromatography), known for this property. The presence of polyhydroxybutyrate, a biopolymer with potentiality in the field of biodegradable bioplastics was also detected. The exploitation of C. linum for a future biotechnological application is also encouraged by the results from a first attempt of cultivating this species in an integrated multi-trophic aquaculture (IMTA) system.

Application of polychaetes in (de)coupled integrated aquaculture: production of a high-quality marine resource

Capitella sp. and Ophryotrocha craigsmithi received a diet of salmon feces to evaluatetheir potential to convert fish waste into valuable marine products, e.g. ingredients for fishfeed formulation. Production rate and body composition (focusing on fatty acid [FA] profiles)were determined for polychaetes fed fresh, acid-preserved or oven-dried salmon feces to evaluatetheir application in (de)coupled integrated multi-trophic aquaculture (IMTA) systems. Coupledproduction refers to direct integration of fish and polychaetes within the same (eco)system,while in decoupled production, units can be spatially or functionally separated. For decoupledproduction, preservation of fish waste is recommended. Although diets contained relatively lowpolyunsaturated FA (PUFA) levels (5−9% of total FAs), both species were rich in PUFAs (>30%of total FAs) and contained the essential FAs for fish. Feeding Capitella sp. the acid-preserveddiet enriched its FA profile. Accumulation of PUFAs, de novo synthesis and/or transfer via bacterialbiomass could have played a role in the upregulation of PUFA content. Amino acid profilesindicated that these polychaetes contained the amino acids essential for fish. Highest growth forboth species was observed when fed fresh feces, whereas preserved diets resulted in negativegrowth rates for O. craigsmithi, suggesting an important role of microbes in polychaete diets.Our results indicate that both species are potential valuable marine products. Given growth rateswith different diets, O. craigsmithi seems more suitable for integration in coupled systems, whileCapitella sp. is interesting for both coupled and decoupled integrated systems

Stress tolerance and photoadaptation to solar radiation in Rhodymenia pseudopalmata (Rhodophyta) through mycosporine-like amino acids, phenolic compounds, and pigments in an Integrated Multi-Trophic Aquaculture system

Rhodymenia pseudopalmata lives in the intertidal zone receiving high doses of solar radiation, including the potentially harmful UVR. Previous studies proved it ability to adapt to different artificial light intensities and salinity concentrations. The aim of this study was to describe the differences on the Mycosporine-like amino acids (MAAs), phenolic compounds, and pigments of R. pseudopalmata due to exposure to high solar radiation. Vegetative thalli were exposed to solar radiation using a Solar Exposure Chambers System (SECS) under an Integrated Multi-Trophic Aquaculture (IMTA) approach with marine fish culture. Samples from natural populations in Playa de Carmen, Mexico were included as reference. The biosynthesis of MAAs, and phenolic compounds were stimulated as a response to the stress caused by the exposure to high solar irradiation. Liquid Chromatography-Mass Spectrometry (LC-MS) revealed seven MAAs and their precursor deoxygadusol. Five MAAs were partially characterized through MS2 and fragmentation patterns suggested a common fragmentation pattern pathway. After seven days (D7), the MAAs total content was significant five-fold higher compared to wild populations (0.26 ± 0.1 mg g−1 DW). The Individual composition increased from four MAAs at D0, up to eight at D7, including deoxygadusol, palythene and usujirene, MAAs with high antioxidant activity. At D7, phenolic compounds increased up to 20%, and the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity reduced the IC50 to 4.0 ± 0.6 mg mL−1. The pigment content, Phycoerythrin (PE):Chl-a, and MAAs:Chl-a ratios might confer a unique photoprotection role from PE and MAAs to Chl-a. Similarly, Fv/Fm which was adapted to the variations of Photosynthetic Active Radiation (PAR) indicated a process of dynamic photoinhibition. Overall, our results evidenced the ability of this species to tolerate the stress to high solar irradiance and suggested the photoadaptation of the thalli. Farming possibilities, expected MAAs productivity, potential applications of MAAs and ecological considerations are also discussed.

Bio mitigation based on integrated multi trophic aquaculture in temperate coastal waters: practice, assessment, and challenges

In general, aquaculture wastes from traditional aquatic organism cultivation rapidly deteriorate the water quality of the surrounding ecosystems, endangering animals living in the area. The integrated multi-trophic aquaculture (IMTA) system is a bio-mitigation strategy to alleviate the adverse impacts caused by aquafarming pollutants on the environment and aquatic species. This study provides an overview of the IMTA system, explains the interactive processes among the different trophic levels, summarizes the major practices being followed around the temperate coastal waters with a field case study in Japan, and discusses the assessment of IMTA bio-mitigation efficiency through experimental greatly dependent on the customs and market values in the local IMTA practice. Bio-mitigation efficiency acquired in a land-based experiment exhibits its limitation in approach and conducts a comprehensive analysis on the possibility of applying numerical models to evaluate IMTA effectiveness. The selection of a suitable candidate organism is estimating that in the same or different culture conditions with various biomasses of extractive species. However, in open water experiments, it is difficult to evaluate the bio-mitigation effect of extractive species because the initial biomass ratio (IBR) of the extractive to target species is too small. Alternatively, the possibility of applying existing numerical models to assess IMTA is relatively low. In conclusion, an optimally designed large-scale IMTA experiment is required, in which the IBR of the extractive to target species is adequately considered, and a full-scale IMTA model should be further improved with a database of individual-based submodels for IMTA candidate organisms. Normal 0 7.8 磅 0 2 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:普通表格; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Times New Roman; mso-bidi-theme-font:minor-bidi;}

Antioxidant and antitumor potential of wild and IMTA-cultivated Osmundea pinnatifida

Osmundea pinnatifida is a red edible seaweed known as pepper dulse. O. pinnatifida was cultivated in the farm of ALGAplus (Ilhavo, Portugal). This farm is integrated with a seabream and seabass commercial aquaculture and uses the nutrient-enriched water resultant from the fish production as its cultivation medium in the integrated multi-trophic aquaculture (IMTA) manner. Wild and IMTA-cultivated samples of O. pinnatifida were screened for antioxidant and antitumor activities. The antioxidant capacity of solvent extracts from wild and IMTA cultivated samples was assessed in two methods (2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC)), and their total phenolic contents (TPC) were estimated. Antitumor activity was evaluated in three different tumor cell lines (HepG-2, MCF-7, and SH-SY5Y) through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Among the solvents used for extraction, dichloromethane was the most effective to extract phenolic compounds and presented higher ORAC. A significant correlation was found between TPC and ORAC, which was also sustained by the principal components analysis (PCA). Dichloromethane extracts induced a cytostatic effect on MCF-7 cells and showed weak cytotoxicity to SH-SY5Y cells and weak impact on cell proliferation. Overall, there were no statistically significant differences in the biological activities shown by the wild and IMTA-cultivated samples. Hence, O. pinnatifida can be obtained in an economical and environmentally sustainable way through IMTA, maintaining bioactive properties in a high potential for further nutraceutical purposes.

Implementation of lyapunov method to analyze the stability of pompano, cantang growth and nutrition dynamical systems

This study aims to determine the analysis stability of dynamical model of pompano, cantang growth, and nutrition on the Integrated Multi-Trophic Aquaculture (IMTA) systems by using the Lyapunov method. The analytical analysis was given to discuss the dynamic behavior of this model. Global stability analysis was performed based on the Lyapunov theory, i.e., construction the function V (x) that is a definite positive scalar function and the derivative of V (x) is defa inite negative. As a verification of the Lyapunov method, we conducted numerical simulations with data taken from IMTA systems in Sea Farming region, Kepulauan Seribu, Indonesia.

The comparison of distribution patterns of macrobenthic assemblages adjacent floating net cage areas at Karang Lebar Island, Jakarta: a multivariate approach

Water and sediment ecosystems are often influenced by fish farming activities especially organic matter that lead to organic enrichment. The macrobenthic community is one of the benthic organisms that can be used as bioindicator to detect disturbances in aquatic environments. The purpose of this study was to compare the distribution patterns of macrobenthic assemblages adjacent to floating net cages situated at Karang Lebar Island, Jakarta using a multivariate approach. Three sampling locations were assessed, each with three stations and three replicates. Each location consisted of a floating net cage of monoculture, a floating net cage of IMTA (Integrated Multi-Trophic Aquaculture), and a reference site at Karang Lebar Island, Kepulauan Seribu, DKI Jakarta. All data concerning macrobenthic presence was expressed using diversity (H’), evenness (e) and dominance (C) indices.Further analysis done using multivariate analysis was presented as 2D-ordination by Nonmetric Multi-Dimensional Scaling (NMDS). The composition of macrobenthic assemblages was dominated by gastropods (18 species), bivalves (9 species) and Polychaeta (7 species). Based on NMDS ordination, there was a tendency of grouping stations by sampling time. It is particularly so between sampling times II and III, and between sampling times I and III. However, this grouping did not occur between sampling times I and II. It may indicate that the macrobenthic assemblages were influenced by certain annual seasons.Meanwhile, depending on sampling locations, the assemblages were influenced by environmental variability. The stations were grouped by the aquacultural areas and reference area on the ordination with some overlapping stations positioned among them. However, the tendency of grouping the stations between IMTA and monocultural sites did not occur, implying both farming practices have a relatively similar impact on the structure of macrobenthic assemblages.

Investigation of a Farm-scale Multitrophic Recirculating Aquaculture System with the Addition of Rhodovulum sulfidophilum for Milkfish (Chanos chanos) Coastal Aquaculture

Globally, coastal aquaculture is growing due to the large demand for marine products. Specific impacts caused by coastal aquaculture on the environment include the discharge of culture farm effluents, stress on ground water (the absence of recycling), nutrient pollution, and diseases of cultured animals. Three methods, integrated multitrophic aquaculture (IMTA), recirculating aquaculture system (RAS), and beneficial bacteria for aquaculture, have been developed to solve these problems. In this study, the advantages of IMTA and RAS were integrated to develop a novel multitrophic recirculating aquaculture system (MRAS) to adapt to the farm-scale culturing of milkfish (Chanos chanos). The photosynthetic bacteria Rhodovulum sulfidophilum was added to enhance the performance of the farm-scale milkfish MRAS. This setting could promote growth of beneficial bacteria, such as the nitrogen cycle-associated microbial community and the anoxygenic phototrophic Acidobacteria community. The ammonia level was reduced, and the total phosphorous level was stable in the water recycled in the MRAS. The cyanobacteria, algae, Vibrio, Escherichia, and other potential pathogenic bacteria communities were inhibited in the MRAS. This study provides an effective design of a water recycling aquaculture system. Milkfish, Asian tiger shrimp (Penaeus monodon), Asian hard clam (Meretrix lusoria), and seaweed (Gracilaria sp.) can be cultured and simultaneously produced in the system.

Oxytetracycline accumulation in the macroalgae Ulva: Potential risks for IMTA systems

Oxytetracycline (OTC) is one of the most used antibiotics in aquaculture. With the development of Integrated Multitrophic Aquaculture (IMTA) systems in order to mitigate some aquacultures' adverse effects, attention needs to be shifted to other co-cultured species that can also accumulate such pharmaceuticals and pose a risk to human consumption. Therefore, the present work evaluated the exposure of the seaweed Ulva to OTC at two realistic concentrations (0.040 and 0.120 mg L−1). Oxytetracycline degradation rates in seawater were dependent on the initial concentration but were not influenced by the presence of Ulva. The macroalgae presented good assimilation rates of OTC, with internal concentrations reaching 40.9934 ng g−1 WW for the lowest concentration tested and 108.6787 ng g−1 WW for the highest, with a steep decrease after 48 and 24 h, respectively. Nonetheless, concentrations were still half of the Maximum Residue Limit set for fish (100 μg kg−1) 48 h after C2 treatment. The highest dosage tested stimulated growth 96 h after the beginning of the trial, although some signs of decay could also be found in Ulva's fronds.

Conceptualizing future scenarios of integrated multi-trophic aquaculture (IMTA) in the Norwegian salmon industry

Norway is the largest global producer and exporter of farmed salmon, however the growth of the industry has coincided with environmental impacts to the marine ecosystem and negative perceptions of salmon farming. Integrated multi-trophic aquaculture (IMTA) is one solution, and scientists in Norway have researched salmon-driven IMTA for over a decade. Their research suggests that IMTA can mitigate some of the negative environmental impacts of salmon farming through waste recycling, however regulations in Norway do not allow IMTA. A participatory workshop was conducted to assess the future of IMTA in Norway, and participants were experts with a comprehensive understanding of the biological and technological processes of IMTA or salmon farming. Two group exercises gave participants the opportunity to conceptualize IMTA in the Norwegian salmon industry, and results indicate that IMTA would improve perceptions of the industry, create skilled jobs in coastal communities, and provide the industry with new sustainable sources of marine ingredients for feed. Participants identified that advocates of IMTA have a difficult task in advancing their agenda because of other stakeholders, such as policymakers and the public concerned with the environmental impacts from salmon farming, communities that regulate access to their coastal zone, and a powerful industry focused on producing salmon. This article explores how advocates could advance IMTA regulations in Norway using agenda building to influence policymakers and agenda setting to sway public opinion. This is the first interdisciplinary article on IMTA in the Norwegian salmon industry using a social science approach.

Is Ulva sp. able to be an efficient biofilter for mariculture effluents?

Nitrogenous compounds such as ammonia, nitrate, and dissolved organic nitrogen (DON) are the main waste components of marine fish pond effluents. These compounds are also regarded as the primary nitrogen sources for seaweed. Aiming at designing an efficient and cost-effective extractive biofilter for fishpond effluents, Ulva lactuca performance and the dynamics of dissolved inorganic (DIN) and DON uptake by this alga grown in the effluents of a land-based integrated multi-trophic aquaculture (IMTA) system were studied. Stocking densities of 1 and 3 kg m−2 were found to be optimal for yield along with specific growth rate (SGR) and protein content, respectively. The presence of ammonia inhibited nitrate uptake by U. lactuca and carbon limitation reduced SGR and yield. However, protein levels of U. lactuca tissue in a carbon-limited situation were higher than when unlimited carbon was made available. When compared with 3 kg m−2 stocking densities, the high C/N ratio in U. lactuca tissue cultured at 1 kg m−2 likely indicated carbon limitation. Ammonia assimilation rate was density dependent. At 1 kg m−2, ammonia uptake was relatively fast, at 4.31 μmole N h−1, and nitrate uptake started only 24 h after ammonia depletion, suggesting this period to be the time required for nitrate reductase (NR) synthesis in the algae tissue. At 2 kg m−2, ammonia uptake was 2.51 μmole N h−1 and nitrate uptake started 24 h after that observed in 1 kg m−2, suggesting that the lower ammonia threshold for uptake by the U. lactuca is around 1.4 μmole L−1. Contrary to 1 and 2 kg m−2 stocking densities, in the 3 kg m−2 stocking density, ammonia uptake was as low as 1.51 μmole N h−1 and no uptake of nitrate appeared to have taken place due to the presence of ammonia in the water. The additional ammonia in the water was found to be due to DON-ammonifying bacteria on the surface of U. lactuca thalli. In the 1ow stocking density, the additional ammonia was relatively low compared to that measured at the high algae density. In the light of the better understanding of the system dynamics achieved in our study, we hypothesize that a set of similar bioreactors using U. lactuca can intensify the system purification efficiency manifold.

Bioremediation of fishpond effluent and production of microalgae for an oyster farm in an innovative recirculating integrated multi-trophic aquaculture system

Integrated multi-trophic aquaculture (IMTA) systems are a promising solution for sustainable aquaculture combining nutrient recycling with increased biomass production. An innovative land-based recirculating aquaculture system (RAS) was studied in France for a 60-day experiment. It combined a European sea bass (Dicentrarchus labrax) RAS with two other production systems: high rate algal ponds (HRAP) with natural marine polyspecific algal assemblages, and oysters in separate open tanks. The objective was the assessment of: 1) the efficiency and the stability of the microalgae bioremediation of the effluent from a fish RAS in spring and summer, 2) the abundance and the diversity patterns of the microalgae biomass for consumption in the oyster compartment of the IMTA. Silicate was added every week after the beginning of the experiment for maintaining a Si:N:P molar ratio of 10:5:1 in the HRAP to encourage the growth of diatoms. The HRAP have an overall removal efficiency of 98.6 ± 0.2% for NO3-N, 98.0 ± 0.4% for NO2-N, 97.3 ± 0.7% for NH4-N and 96.1 ± 0.6% for PO4-P, with removal rates of 335.8 ± 0.8, 23.6 ± 0.2, 30.9 ± 0.2, and 22.3 ± 0.2 mg m−2 d−1, respectively. The concentration of total suspended solid (TSS) and chlorophyll a (chl a) increased during the experiment and reached maximum values on day 46 (135.3 ± 34.7 mg TSS l−1 and 0.42 ± 0.03 mg chl a l−1) after which the microalgae collapsed due to a CO2 limitation (pH ca. 10). Sequencing analysis revealed that the microalgae community was dominated by Tetraselmis sp. from day 1 to day 16 (45.7% to 73.8% relative abundance). From day 30 to day 43 the culture was dominated by diatoms, Phaeodactylum sp. (83.4% to 98.1% relative abundance). Although the stable carbon isotope signatures confirmed that the microalgae were consumed, oysters' growth was limited in the RAS-IMTA, suggesting that oysters were under stress or not fed enough.