Multitrophic Systems Research Articles

Enhanced Growth Potential of Tilapia (Oreochromis niloticus) Through Maggot-Based Feeding in Multi-Trophic Systems

Highly nutritious insects, such as black soldier fly (BSF) larvae, also referred toas maggot, have been evaluated as feed in monoculture systems, but their use in multi-trophic systems has not been previously investigated. This study used maggot-based feed in a multi-trophic system on a laboratory scale to evaluate the survival and growth performance of tilapia (Oreochromis niloticus). Tilapia were cocultured with freshwater lobster, freshwater clams, and paddy. Four experimental diets were used including a commercial pellet as a control (CP), live maggots (LM), dried maggots (DM), and supplemented maggots (SM). Tilapia (initial weight, 4.1 ± 0.2 g) and other organisms were reared in plastic tanks (water volume 50 L) and randomly distributed into 12 tanks, each containing 20 individual tilapia. The experimental diets were given four times a day at a feeding rate of 10% tilapia biomass. After 28 days of feeding, the survival and growth of tilapia on the CP diet were 90.0% and 2.8% day-1, LM 93.3% and 2.7% day-1, DM 93.3% and 3.3% day-1, and SM 90.0% and 3.1% day-1, respectively. There was no significant effect (P > 0.05) on the survival performance among the experimental diets. However, the growth confirmed by Specific Growth Rate (SGR) showed a significant effect (P < 0.05). SGR values were found to be significantly higher in the DM and SM diets than in the CP diet. An important finding of this research is the potential of maggot-based feed to increase the growth of tilapia in multi-trophic systems without impairing their survival.

A multitrophic culture system for the production of black soldier fly larvae (Hermetia illucens)

Goals number 2, 11 and 12 of the 17 sustainable development goals, enacted by the United Nations as part of the 2030 Agenda for sustainable development, aim to end hunger as a priority, create sustainable cities and above all encourage responsible consumption and production. With increasing world population and higher demand for food, we need to find ways of producing cheap sources of protein and lipid that may in turn be used as animal or aquaculture feed. A multitrophic system involving mealworm larvae (MWL, Tenebrio molitor) and black soldier fly larvae (BSFL, Hermetia illucens) was developed to transform fruit and vegetable kitchen waste into usable biomass. MWL, fed mainly on kitchen waste, reached an average prepupal length of 2.4 cm, fresh weight of 0.12 g and dry matter protein and lipid contents of 44.2% and 16.5% respectively, with an average specific growth rate (SGR) of 2.2%/day and a feed conversion ratio (FCR) of 7.9. Conversely, BSFL fed on a variety of feeds, including MWL frass, kitchen waste and oats, had an average prepupal length of 1.3 cm, fresh weight of 0.16 g and dry matter protein and lipid contents of 41.4% and 26.3% respectively, with an average SGR and FCR of 4.3%/day and 8.9 respectively. The BSFL fed MWL frass obtained some of highest SGR and lowest FCR values, with one group achieving 7.5%/day and 2.9 respectively. This investigation has demonstrated the feasibility of a multi-trophic production system using kitchen waste to feed MWL whose frass was in turn used to feed BSFL thereby producing protein- and lipid-rich biomass that can serve as animal or aquaculture feed.

Effects of nanoplastic exposure routes on leaf decomposition in streams

Polystyrene nanoparticles (PS NPs) released from plastic products have been demonstrated to pose a threat to leaf litter decomposition in streams. Given the multitrophic systems of species interactions, the effects of PS NPs through different exposure routes on ecosystem functioning remain unclear. Especially dietary exposure, a frequently overlooked pathway leading to toxicity, deserves more attention. A microcosm experiment was conducted in this study to assess the effects of waterborne and dietary exposure to PS NPs on the litter-based food chain involving leaves, microbial decomposers, and detritivores (river snails). Compared to waterborne contamination, dietary contamination resulted in lower microbial enzyme activities and a significantly higher decrease in the lipid content of leaves. For river snails, their antioxidant activity was significantly increased by 20.21%–69.93%, and their leaf consumption rate was significantly reduced by 16.60% through the dietary route due to the lower lipid content of leaves. Besides, the significantly decreased nutritional quality of river snails would negatively influence their palatability to predators. The findings of this study indicate that dietary exposure to PS NPs significantly impacts microbial and detritivore activities, thus affecting their functions in the detritus food chain as well as nutrient cycling.

Urban intensity gradients shape community structure, life‐history traits and performance in a multitrophic system

Abstract Urban ecosystems are formed by pronounced socio‐ecological gradients, which are distinct from other ecosystems and can simultaneously filter and promote taxa, ultimately affecting their interactions. However, the strength of the effect of filtering and facilitation across the different trophic levels could vary among biotic and abiotic factors. Here, we investigate the effects of habitat amount, temperature and host‐enemy biotic interactions in shaping communities of cavity‐nesting bees and wasps and their natural enemies. We installed trap‐nests in 80 sites distributed along urban intensity gradients in five European cities (Antwerp, Paris, Poznan, Tartu and Zurich). We quantified the species richness and abundance of hosts and their natural enemies, as well as two performance traits (survival and parasitism) and two life‐history traits (sex ratio and number of offspring per nest for the hosts). We analysed the importance of the abiotic and biotic variables using generalised linear models and multi‐model inference. We found that habitat amount was the main driver of multiple host responses, with larger habitat amounts resulting in higher species richness and abundance for hosts and natural enemies, as well as a larger probability of survival and a larger number of brood cells for hosts. Local resources proxies shaped both bees and wasps and indicate different uses of existing vegetation between bees and wasps. Temperature proxies had a minor role in shaping host and natural enemies. Biotic interactions were a main driver of host and enemy community structure, with natural enemies being strongly affected by host availability, that is, with direct density‐dependence between hosts and their natural enemies. Overall, our study highlights the importance of habitat amount and temperature in shaping urban food webs, as well as on biotic interactions through direct effects on hosts responses and the subsequent consequences for their natural enemies. As cities prepare to tackle the consequences of global change, strategies that make it possible to maintain habitat and mitigate urban overheating emerge as a key urban adaptation for biodiversity conservation.

Greenhouse melon crop protection and production through the compatible use of a parasitoid with endophytic entomopathogenic ascomycetes

This study delves into the compatible use of a parasitoid with multifunctional endophytic Entomopathogenic Ascomycetes (EA) in IPM under greenhouse conditions. The parasitoid Hyposoter didymator was evaluated against Spodoptera littoralis in a multitrophic system with melon plants that were endophytically colonized by one of three EA strains (Metarhizium brunneum [one] or Beauveria bassiana [two]). In the first scenario, plants were inoculated by three different methods, and after infestation with noctuid larvae, the parasitoid was released at a 1:20 ratio. Microbiological and molecular techniques allowed the identification of progressive colonization throughout the whole plant life cycle, and for B. bassiana, approximately 20% of seeds from new fruits were colonized. The parasitoid was shown to be compatible with all strains and application methods, with total mortality rates ranging from 11.1 to 77.8%. Significant lethal and sublethal effects, a decrease in pupal weight and mortality of pupae showing abnormalities and an extension of the immature developmental times were observed for different strain–application method combinations. Additionally, the fungal treatments improved crop growth, as revealed by the significant gains in plant weight. In a second scenario (by inoculating plants with the fungi only by leaf spraying), and after infestation with noctuid larvae, the parasitoid was released at a 1:10 ratio, which revealed the remote fungal effect from the inoculation point and confirmed the compatibility of the parasitoid-EA-based strategy. These findings underscore the compatible use of a parasitoid with endophytic EA for S. littoralis control that can additionally exploit their multifunctionality for sustainable crop production.

The method of complex biological water treatment in aquaponic recirculation systems

The article discusses the results of experimental research work on the development of technical solutions aimed at creating an integrated innovative biotechnology for recycled water treatment in recirculating aquaculture systems. Schemes and descriptions of experimental units using the multitrophic approach when creating water treatment systems are given. The system is completed according to the principle of integration into a single multitrophic system of spatially delimited biomodules with various types of hydrobionts, where particular types of organisms serve as a food base for subsequent trophic levels. As a result of trophic chains, phytoplankton and zooplankton are cultivated and used as starter live food when rearing juvenile fish. Natural food base contributes to the production of high-quality viable fish stock, which is essential for commercial fish farming. The use of tiered units can significantly reduce the need for production space. Polyculture cultivation of various species of fish, crustaceans, and mollusks together with hydroponic plants allows to diversify production for obtaining additional profit and reducing the risks. Cultivation of high-value fish species (e.g. sturgeon) or crustaceans (Australian red claw) together with less valuable cyprinids, tilapia or African catfish allows to promote products in different market segments.

Combine effects of multiple environmental factors on growth and nutrient uptake of euryhaline seaweed growth in integrated multitrophic aquaculture systems

Macroalgae are biofilters that increase the ability of the environment to assimilate nutrients and whose biomass finds different uses in the industrial sector. The growth of Ulva sp. and Gracilaria lemaneiformis and their ability to remove nutrients from enriched water was assessed in a series of laboratory experiments. This study tested their growth performance under: a) three different salinities (15, 20 and 25 psu), b) three different initial densities (low(1 g/l), medium (2 g/l) and high(3 g/l)) and c) four light intensities (1000, 2000, 3000 and 4000 lx). The best results regarding the specific growth rate were achieved for Ulva and Gracilaria (SGR 11 % and 6 %) under light intensity of 3000 lx, salinity of 25 psu, and density of 2 g/l. After four days >80 % of NH4-N and 95 % of PO4-P had been removed from the tanks by Ulva sp. The growth and production performance were tested among: 1) three different depths (10, 20 and 30 cm) in multitrophic system (Fishes + Macroalgae). Finally, based on the best combination obtained from the first phase of the experiment, it was set up the last experiment where the nutrient uptake performances of Ulva were tested among three multitrophic systems (IMTA (Fishes +mussel + Ulva), “Fishes + Ulva”, “Fishes + mussel”). Although the best cultivation depth was 10 cm for both Ulva and Gracilaria, there were significant differences between the WBP (Wet Biomass Production) of the two species (Ulva WBP =46 ± 8.02 g m−2d−1; Gracilaria WBP = 8.5 ± 0.51 g m−2d−1) (p < 0.05). Finally, after the 8th-day experiments, the concentrations of NH4–N were lower in the “Fishes+Ulva” (44.32 %) system and IMTA (27.36 %) system compared with the “Fishes+mussel” system. Moreover, phosphates (PO4-P) concentration decreased by 51.75 % and 57.58 % in the aquaria with “Fishes+Ulva” system and IMTA system, respectively. The results obtained in this study show that Ulva sp. and G. lemaneiformis can grow satisfactorily and absorb nutrients from water efficiently, proving to be suitable candidates for wastewater treatment of aquaculture facilities.

Biological Responses of Oyster Crassostrea gasar Exposed to Different Concentrations of Biofloc

Oysters have the potential to be a part of more sustainable farming systems, such as multitrophic systems integrated into biofloc systems, due to their filtration activity, which enables them to act as organic consumers. However, the stress experienced by animals in a system with a high organic load can compromise their productive performance. The objective of this study was to evaluate the biological responses of Crassostrea gasar oysters when exposed to different concentrations of total suspended solids in biofloc systems. The oysters were exposed to four different concentrations of solids for 28 days. Hall effect sensors were installed on the outside of the shells to detect the movement of the oyster valves. Also, biochemical and histological analyses were conducted to assess the biological responses of the oysters to exposure to varying levels of solids. A difference in valve opening detected by the Hall sensors was observed from the second week of culture, indicating a relationship between shell closure and higher concentrations of suspended solids present in the system. In terms of biochemical analysis, a significant increase in lipid damage was observed in treatments with medium and high levels of total suspended solids compared with the control group. Conversely, no changes were observed in the gill structure of the oysters caused by the concentrations of suspended solids in the system when compared with the control. According to the analyses of gill activity and biochemistry, it is suggested that C. gasar should be cultured with total suspended solids at less than 200 mg/L. Oysters cultivated in a biofloc system keep their shells closed when subjected to high concentrations of total suspended solids; concentrations of total suspended solids below 200 mg/L do not induce oxidative stress, changes in behavior or histological alterations in C. gasar oysters cultivated in a biofloc system.

Further evidences of an emerging stingless bee-yeast symbiosis.

Symbiotic interactions between microorganisms and social insects have been described as crucial for the maintenance of these multitrophic systems, as observed for the stingless bee Scaptotrigona depilis and the yeast Zygosaccharomyces sp. SDBC30G1. The larvae of S. depilis ingest fungal filaments of Zygosaccharomyces sp. SDBC30G1 to obtain ergosterol, which is the precursor for the biosynthesis of ecdysteroids that modulate insect metamorphosis. In this work, we find a similar insect-microbe interaction in other species of stingless bees. We analyzed brood cell samples from 19 species of stingless bees collected in Brazil. The osmophilic yeast Zygosaccharomyces spp. was isolated from eight bee species, namely Scaptotrigona bipunctata, S. postica, S. tubiba, Tetragona clavipes, Melipona quadrifasciata, M. fasciculata, M. bicolor, and Partamona helleri. These yeasts form pseudohyphae and also accumulate ergosterol in lipid droplets, similar to the pattern observed for S. depilis. The phylogenetic analyses including various Zygosaccharomyces revealed that strains isolated from the brood cells formed a branch separated from the previously described Zygosaccharomyces species, suggesting that they are new species of this genus and reinforcing the symbiotic interaction with the host insects.

Reciprocal influence of soil, phyllosphere, and aphid microbiomes

BackgroundThe effect of soil on the plant microbiome is well-studied. However, less is known about the impact of the soil microbiome in multitrophic systems. Here we examined the effect of soil on plant and aphid microbiomes, and the reciprocal effect of aphid herbivory on the plant and soil microbiomes. We designed microcosms, which separate below and aboveground compartments, to grow oak seedlings with and without aphid herbivory in soils with three different microbiomes. We used amplicon sequencing and qPCR to characterize the bacterial and fungal communities in soils, phyllospheres, and aphids.ResultsSoil microbiomes significantly affected the microbial communities of phyllospheres and, to a lesser extent, aphid microbiomes, indicating plant-mediated assembly processes from soil to aphids. While aphid herbivory significantly decreased microbial diversity in phyllospheres independent of soil microbiomes, the effect of aphid herbivory on the community composition in soil varied among the three soils.ConclusionsThis study provides experimental evidence for the reciprocal influence of soil, plant, and aphid microbiomes, with the potential for the development of new microbiome-based pest management strategies.

Does agricultural intensification impact pest regulation service by frogs in a natural multi-trophic system?

Agricultural intensification is a major driver of biodiversity loss. However, the exact impacts of such loss of key ecosystem service (ES) provisions in agriculture require more scrutiny. We assessed the population loss impacts of a key ES-providing species in an agricultural landscape. We tested the hypothesis that intensive agriculture causes density reduction of frogs known as pest regulators and that negatively affects pest regulation. Different frog densities (high and low) observed in a previous study in low and high agricultural intensification areas were used as treatments in a semi-controlled field experiment. Functional response of the frog species was also studied. Neither high nor low frog density had any significant effect on respective pest populations. Limited feeding rate of the frog species might have contributed to reduced predation pressure on pests. Surprisingly, at low density, frogs significantly reduced the arthropod natural enemies, probably their preferred prey due to the latter’s agility. Unlike in low frog density treatment, increased intraspecific competition at high frog density made them seek out pests as alternative prey to the preferred arthropod pest enemies, whose populations were not affected by frog density. This study for the first time links the population loss of frogs, a potential bio-control agent to ES provision in a multi-trophic system.

Community context mediates effects of pollinator loss on seed production

AbstractA critical goal for ecologists is understanding how ongoing local and global species losses will affect ecosystem functions and services. Diversity–functioning relationships, which are well‐characterized in primary producer communities, are much less consistently predictable for ecosystem functions involving two or more trophic levels, particularly in situations where multiple species in one trophic level impact functional outcomes at another trophic level. This is particularly relevant to pollination functioning, given ongoing pollinator declines and the value of understanding pollination functioning for single plant species like crops or threatened plants. We used spatially replicated, controlled single‐pollinator‐species removal experiments to assess how changes in bumble bee species richness impacted the production of fertilized seeds in a perennial herb—Delphinium barbeyi—in the Rocky Mountains of Colorado, USA. To improve predictability, we also assessed how traits and abundances in the plant and bumble bee communities were related to D. barbeyi reproductive success. We hypothesized that trait‐matching between pollinator proboscis length and D. barbeyi's nectar spurs would produce a greater number of fertilized seeds, while morphological similarity within the floral community would dilute pollination services. We found that the effects of pollinator removal differed depending on the behavioral patterns of pollinators and compositional features of the plant and pollinator communities. While pollinator floral fidelity generally increased D. barbeyi seed production, that positive effect was primarily evident when more than half of the Bombus community was experimentally removed. Similarly, communities comprising primarily long‐tongued bees were most beneficial to D. barbeyi seed production in tandem with a strong removal. Finally, we observed contrasting effects of morphological similarity in the plant community, with evidence of both competition and facilitation among plants. These results offer an example of the complex dynamics underlying ecosystem function in multitrophic systems and demonstrate that community context can impact diversity–functioning relationships between trophic levels.

Functional diversity increases the resistance of a tritrophic food web to environmental changes

In the light of global climate change and biodiversity loss, understanding the role of functional diversity in the response of food webs to environmental change is growing ever more important. Using a tritrophic food web model, with a variable degree of functional diversity at each trophic level, we studied the role of functional diversity on the resistance of a system against press perturbations. Perturbations affected either nutrient availability or the mortality of the species, which can be interpreted as effects of eutrophication and warming, respectively. We compared food webs with different levels of functional diversity by investigating the species trait and biomass dynamics, the overall changes in the species’ standing biomass as measured by the warping distance, and the duration of the system transients after the onset of a press perturbation (transition time). We found that higher functional diversity increased resistance since it buffered trophic cascading effects and delayed the onset of oscillatory behaviour caused by either bottom-up forcing via perturbations to nutrient concentration or top-down forcing via perturbations to mortality rate. This increased resistance emerged from a higher top-down control of the intermediate species on the basal species. Functional diversity also promoted a higher top biomass, in particular via a higher proportion of top selective species undergoing high mortality rates. Additionally, functional diversity had context-dependent effects on warping distances, and increased transition times. Overall, this study encourages accounting for functional diversity in future investigations about the response of multitrophic systems to global change and in management strategies.

Environmental quality improvement of a mariculture plant after its conversion into a multi-trophic system

Integrated Multitrophic Aquaculture (IMTA) seems to be one of the best solutions for sustainable aquaculture. Within the Remedia LIFE Project, an experimental IMTA plant was put in place in the Mar Grande of Taranto (Mediterranean Sea, Southern Italy). The polyculture of several bioremediating organisms, such as mussels, tubeworms, sponges, and seaweeds, was combined with a coastal cage fish farm, in order to remove organic and inorganic wastes coming from the fish’s metabolism. To verify the effectiveness of the system, the ex ante measurement of chemical-physical variables, trophic status, microbial contamination, and zoobenthos community health was compared with the results of the same measurement performed one year and two years after the implementation of the experimental IMTA plant. The results were encouraging, since a reduction in total nitrogen concentration in the seawater (from 43.4 ± 8.9 to 5.6 ± 3.7 μM/l), a reduction in microbial pollution indicators in the seawater (total coliforms: from 280 ± 18 MPN/100 mL to 0; E. coli: from 33 ± 1.3 MPN/100 mL to 0) and in the sediments (total coliforms: from 230 ± 6.2 MPN/100 g to 170 ± 9; E. coli: from 40 ± 9.4 MPN/100 g to 0), an enhancement of the trophic status (TRIX: from 4.45 ± 1.29 to 3.84 ± 0.18), and an increase in the zoobenthic quality indices and biodiversity were recorded (AMBI: from 4.8 to 2.4; M-AMBI: from 0.14 to 0.7). These results prove that the Remedia LIFE project's purpose was achieved. The selected bioremediators worked synergistically, improving water and sediments quality within the fish farm area. Moreover, bioremediating organisms increased their weight as a result of wastes uptake, producing, as co-products, large amounts of additional biomass. This could be commercially exploited, thus being an added value of the IMTA plant. Based on our findings, the promotion of eco-friendly practices to ameliorate ecosystem health should be encouraged.

Integrated multitrophic aquaculture system applied to shrimp, tilapia, and seaweed (Ulva ohnoi) using biofloc technology

Integrated multitrophic aquaculture (IMTA) is a model that integrates organisms from different trophic levels, all sharing the same production system and, consequently, the nutrients. This study adopted shrimp (Penaeus vannamei) as the main species, tilapia (Oreochromis niloticus) as an organic consumer, and the seaweed (Ulva ohnoi) at different densities as an inorganic consumer in a biofloc production system. The study consisted of an experiment with three treatments and four replicates each: 1) No seaweed; 2) Seaweed 1 g L−1 (density of 1 g L−1 of U. ohnoi), and 3) Seaweed 2 g L−1 (density of 2 g L−1 of U. ohnoi). Shrimp (3.82 ± 0.05 g) were stocked in 800 L tanks at a density of 275 shrimp m−3, fish (14.44 ± 0.57 g) in 90 L tanks at a density of 267 tilapia m−3, and 50 and 100 g of seaweed stocked in 50 L tanks, corresponding to treatments with 1 and 2 g L−1, respectively. The integration of U. ohnoi at densities of 1 g L−1 and 2 g L−1 with P. vannamei and O. niloticus benefited the system through higher nitrogen (13,22 and 13,10% higher in the treatments 1 g L−1 and 2 g L−1 respectively) and phosphorus recovery (25,57 and 34% respectively) and an increase in total productivity (15,32 and 19,22% respectively), generating an ecological gain. Considering the similar final biomass of seaweed in a multitrophic system with shrimp and tilapia, the use of U. ohnoi at a density of 2 g L−1 is recommended since nutrient recovery by fish and shrimp was higher at this density.

Life-cycle traits in the demosponge Hymeniacidon perlevis in a land-based fish farm.

The demosponge Hymeniacidon perlevis is characterized by wide geographic distribution and great adaptability to numerous and highly variable climatic and hydrological conditions. Indeed, the species can colonize many different environments, including several unusual ones, such as concrete drainage conduits of a marine land-based fish farm plant. This research aimed to enhance existing knowledge on the reproductive cycle and growth performance of H. perlevis while also evaluating the impact of a controlled supply of trophic resources, wastewater flow and constant water temperature on these biological traits. Specimens included in this one-year study inhabited drainage conduits of a land-based fish farm. The approach included measurements of sponge biomass and occurrence and abundance of reproductive elements across different seasons and environmental parameters, such as fish biomass, trophic resources, and wastewater flow. Sponge growth and reproductive elements, including oocytes, spermatic cysts, and embryos, were measured monthly in sponges positioned in the drainage conduit, thus with different trophic resources but with constant water temperature. Finally, we used generalized additive models to describe variables that contribute the most to the growth of sponges. Growth performance showed marked variations during the study period. The highest increase in sponge volume was observed from August/September to January/March. The volume of sponges was principally determined by the reduction of reared fish biomass and the increase of pellet amount and wastewater flow. Sponge specimens exhibited an active state during the entire study, as proven by the occurrence of recruits. However, sexual elements were only sporadically observed, thus not permitting the recognition of a true sexual cycle. The results of the present study confirmed that H. perlevis exhibits high flexibility and adaptability to the differential, and somewhat extreme, environmental conditions. Indeed, this species can live, grow and reproduce in the drainage conduits of the fish farm, where the species face constant darkness, water temperature and continuous nutritional supply. In such conditions, H. perlevis display an active state during the entire year, while avoiding stages of decline and long dormancy usually observed in wild populations. It seems plausible that stable environmental conditions induce an almost continuous sexual phase, probably under the control of endogenous factors. No asexual elements were detected, although it was impossible to exclude the contribution of asexual reproduction in the origin of the newly settled sponges, which were repeatedly detected throughout the study. The growth performance seemed linked to the fish farm conditions, thus providing useful indications on the best maintenance conditions for H. perlevis in land-based integrated multitrophic systems, where the species could be used for wastewater treatment.

Polyculture of Pacific White Shrimp Litopenaeus vannamei (Boone) and Red Seaweed Gracilaria birdiae (Greville) under Different Densities

The present study evaluated a polyculture system with Pacific white shrimp (Litopenaeus vannamei) and the macroalga Gracilaria birdiae and its potential to remove nutrients. The experimental design consisted of a shrimp monoculture of 100 animals/m2 (T0) and three multitrophic cultures with L. vannamei (100 animals/m2) and with G. birdiae at densities of 500 (T500), 1000 (T1000), and 2000 (T2000) g/m2. Nitrogen and phosphorus concentrations decreased at the beginning of the experiment in the treatments with macroalgae, but this reduction was not maintained throughout the cultivation period. The stable values of G. birdiae biomass were perhaps related to the high turbidity of the water. There was an increase in shrimp biomass during cultivation, which reached the final individual averages of 7.5 g (T0), 7.6 g (T500), 5.9 g (T1000), and 7.5 g (T2000), with no significant differences between treatments. Nevertheless, the absence of macroalgae growth provides no added profit for the producer. Thus, there is no economic advantage in using G. birdiae in an integrated multitrophic system with L. vannamei at a high density and conditions of high water turbidity.

The method of complex biological water treatment in aquaponic recirculation systems

The article discusses the results of experimental research work on the development of technical solutions aimed at creating an integrated innovative biotechnology for recycled water treatment in recirculating aquaculture systems. Schemes and descriptions of experimental units using the multitrophic approach when creating water treatment systems are given. The system is completed according to the principle of integration into a single multitrophic system of spatially delimited biomodules with various types of hydrobionts, where particular types of organisms serve as a food base for subsequent trophic levels. As a result of trophic chains, phytoplankton and zooplankton are cultivated and used as starter live food when rearing juvenile fish. Natural food base contributes to the production of high-quality viable fish stock, which is essential for commercial fish farming. The use of tiered units can significantly reduce the need for production space. Polyculture cultivation of various species of fish, crustaceans, and mollusks together with hydroponic plants allows to diversify production for obtaining additional profit and reducing the risks. Cultivation of high-value fish species (e.g. sturgeon) or crustaceans (Australian red claw) together with less valuable cyprinids, tilapia or African catfish allows to promote products in different market segments.

Sıfır atığa doğru: Su ürünleri yetiştiriciliğinde sürdürülebilir atık yönetimi

Increases in aquaculture production due to higher demand for aquatic foods result in an increase in the amount of aquaculture wastewater. This situation highlights the need for the effective treatment of wastewater in sustainable aquaculture. Today, instead of traditional physical and chemical methods in the treatment of wastewater originating from aquaculture, ecosystem-sensitive and by-product-oriented systems have begun to be adopted. The main principle of the zero-waste approach is the recycling of the nutrients in the wastewater to produce another food. In this new innovative approach, the production of other organisms from the different trophic levels using the wastewater of aquaculture in the integrated multi-trophic systems (such as aquaponics) is possible to recycle the nutrients. It has been considered the integrated multi-trophic systems (IMTA) more valuable as these systems can be used both in environment-friendly wastewater treatment and in the conversion of nutrients in wastewater to biomass. The nutrients such as nitrogen and phosphorus in aquaculture wastewater can be utilized to produce two organisms (i.e. fish+mussel) or three organisms (i.e. fish+mussel+seaweed) through IMTA. Aquaculture wastewater can be used to reduce the nutrients in constructed wetlands and plant lagoons representing the reasonable approach for sustainable aquaculture and wastewater treatment. Here, the innovative approach to sustainable aquaculture wastewater treatment was reviewed for the current and innovative technologies. It was emphasized that the need for environment-friendly wastewater treatment Technologies such as aquaponics, enlargement of constructed wetlands, or increase in using the integrated multi-trophic production systems (IMTA) in practice are recommended for sustainable aquaculture.

Genomic characterization of viruses associated with the parasitoid Anagyrus vladimiri (Hymenoptera: Encyrtidae).

Knowledge on symbiotic microorganisms of insects has increased dramatically in recent years, yet relatively little data are available regarding non-pathogenic viruses. Here we studied the virome of the parasitoid wasp Anagyrus vladimiri Triapitsyn (Hymenoptera: Encyrtidae), a biocontrol agent of mealybugs. By high-throughput sequencing of viral nucleic acids, we revealed three novel viruses, belonging to the families Reoviridae [provisionally termed AnvRV (Anagyrus vladimiri reovirus)], Iflaviridae (AnvIFV) and Dicistroviridae (AnvDV). Phylogenetic analysis further classified AnvRV in the genus Idnoreovirus, and AnvDV in the genus Triatovirus. The genome of AnvRV comprises 10 distinct genomic segments ranging in length from 1.5 to 4.2 kb, but only two out of the 10 ORFs have a known function. AnvIFV and AnvDV each have one polypeptide ORF, which is typical of iflaviruses but very un-common among dicistroviruses. Five conserved domains were found along both the ORFs of those two viruses. AnvRV was found to be fixed in an A. vladimiri population that was obtained from a mass rearing facility, whereas its prevalence in field-collected A. vladimiri was ~15 %. Similarly, the prevalence of AnvIFV and AnvDV was much higher in the mass rearing population than in the field population. The presence of AnvDV was positively correlated with the presence of Wolbachia in the same individuals. Transmission electron micrographs of females' ovaries revealed clusters and viroplasms of reovirus-like particles in follicle cells, suggesting that AnvRV is vertically transmitted from mother to offspring. AnvRV was not detected in the mealybugs, supporting the assumption that this virus is truly associated with the wasps. The possible effects of these viruses on A. vladimiri's biology, and on biocontrol agents in general, are discussed. Our findings identify RNA viruses as potentially involved in the multitrophic system of mealybugs, their parasitoids and other members of the holobiont.