Integrated Multi-trophic Aquaculture Research Articles

Nutrients removal from integrated multi-trophic aquaculture (IMTA) water using waste stabilization ponds (WSP)

Nutrients enrichment due to waste from Keramba Jaring Apung (KJA) aquaculture is one of the main causes of eutrophication in Indonesian Lakes and Reservoirs. Integrated multi-trophic aquaculture (IMTA) is one of environmentally friendly aquaculture that currently being developed at the Research Center (RC) for Limnology - National Research and Innovation Agency (BRIN). This aquaculture would re-use its water, along with fish waste and leftover fish pellets, to grow Duckweed (Lemna sp.) in its ponds system as additional feed. However, due to closed water recirculation in IMTA ponds system, the water quality would eventually deteriorate which would be marked with high turbidity of organic solid waste and low dissolved oxygen (DO). This study aims to improve water quality from aquacultures activity, especially in nutrients (nitrogen and phosphorus) reduction, using a constructed wetland (CW) system. This system consists of waste stabilization ponds (WSP) and compartments of CW and adsorbent. During this initial stage, IMTA water was treated in the WSP for then observed for its improvements in the nutrients and other water quality parameters. This research was conducted from July to September 2019 in the Prototype Laboratory of RC for Limnology-BRIN. Parameters of DO, conductivity, pH, oxidation reduction potential (ORP), and salinity were observed using a calibrated water quality checker (WQC) Horriba©, while nutrients parameters in the form of N-NH4, N-NO2, N-NO3, P-PO4, and dissolved organic matters (DOM) were measured in the laboratory referring to the standard method of the American Public Health Association (APHA). Results showed that average values of turbidity and electrical conductivity parameters were reduced from 102 to 76 NTU and 0.21 to 0.14 mS/cm, respectively. Average nutrients reductions were also found from N-NO2, N-NO3 and P-PO4 parameters of 85.5%, 44.3% and 37%, respectively. Significant changes were observed in parameters of DO and N-NH4. DO was increased from 4.63 mg/L to 7.44 mg/L, while N-NH4 were reduced for 81%. Even though the experiments were not conducted during low DO conditions of water from IMTA ponds, improvements from the vital water quality parameters after treatment in the WSP were observed.

Metagenomic Insights into the Structure of Microbial Communities Involved in Nitrogen Cycling in Two Integrated Multitrophic Aquaculture (IMTA) Ponds

The microbial structure and metabolic potential, particularly with regard to nitrogen (N) cycling, in integrated multitrophic aquaculture (IMTA) ponds with shrimp remain unclear. In this study, an analysis of microbial community taxonomic diversity and a metagenomic analysis of N-related genes were performed in a shrimp-crab pond (Penaeus japonicus-Portunus trituberculatus, SC) and a shrimp-crab-clam pond (P. japonicus-P. trituberculatus-Sinonovacula constricta, SCC) to evaluate microbial structure and N transformation capacities in these two shrimp IMTA ponds. The composition of the microbial communities was similar between SC and SCC, but the water and sediments shared few common members in either pond. The relative abundances of N cycling genes were significantly higher in sediment than in water in both SC and SCC, except for assimilatory nitrate reduction genes. The main drivers of the differences in the relative abundances of N cycling genes in SC and SCC were salinity and pH in water and the NO2− and NH4+ contents of pore water in sediment. These results indicate that the coculture of S. constricta in a shrimp-crab pond may result in decreased N cycling in sediment. The reduced N flux in the shrimp IMTA ponds primarily originates within the sediment, except for assimilatory nitrate reduction.

Effects of climate and environmental variance on the performance of a novel peatland-based integrated multi-trophic aquaculture (IMTA) system: Implications and opportunities for advancing research and disruptive innovation post COVID-19 era

Advancing wet peatland ‘paludiculture’ innovation present enormous potential to sustain carbon-cycles, reduce greenhouse-gas (GHG) gas emissions and to transition communities to low-carbon economies; however, there is limited scientific-evidence to support and enable direct commercial viability of eco-friendly products and services. This timely study reports on a novel, paludiculture-based, integrated-multi-trophic-aquaculture (IMTA) system for sustainable food production in the Irish midlands. This freshwater IMTA process relies on a naturally occurring ecosystem of microalgae, bacteria and duckweed in ponds for managing waste and water quality that is powered by wind turbines; however, as it is recirculating, it does not rely upon end-of-pipe solutions and does not discharge effluent to receiving waters. This constitutes the first report on the effects of extreme weather events on the performance of this IMTA system that produces European perch (Perca fluviatilis), rainbow trout (Oncorhynchus mykiis) during Spring 2020. Sampling coincided with lockdown periods of worker mobility restriction due to COVID-19 pandemic. Observations revealed that the frequency and intensity of storms generated high levels of rainfall that disrupted the algal and bacterial ecosystem in the IMTA leading to the emergence and predominance of toxic cyanobacteria that caused fish mortality. There is a pressing need for international agreement on standardized set of environmental indicators to advance paludiculture innovation that addresses climate-change and sustainability. This study describes important technical parameters for advancing freshwater aquaculture (IMTA), which can be future refined using real-time monitoring-tools at farm level to inform management decision-making based on evaluating environmental indicators and weather data. The relevance of these findings to informing global sustaining and disruptive research and innovation in paludiculture is presented, along with alignment with UN Sustainable Development goals. This study also addresses global challenges and opportunities highlighting a commensurate need for international agreement on resilient indicators encompassing linked ecological, societal, cultural, economic and cultural domains.

The growth of tiger shrimp (Penaeus monodon) and its dynamics of water quality in integrated culture

Abstract. Amalia R, Rejeki S, Widowati LL, Ariyati RW. 2021. The growth of tiger shrimp (Penaeus monodon) and its dynamics of water quality in integrated culture. Biodiversitas 23: 593-600. Intensive shrimp culture with high density will have an impact on environmental problems. One of them is the accumulation of organic materials. Integrated Multi-trophic Aquaculture (IMTA) is an alternative effort to reduce the environmental impact of aquaculture activities, which can help maintain the balance of the ecosystem. Seaweed and shellfish in the culture system can improve environmental quality. Therefore, it can assist in optimizing friendly environmental shrimp culture. This study aimed to find out the growth of tiger shrimp and the role of seaweed and blood cockles and its dynamics of water quality. Twelve fiberglass tanks containing 800 L of brackish water and filled with ± 10 cm of clay sediment were arranged randomly. This study used 4 treatments and 3 replications, including treatment A (tiger shrimp), B (tiger shrimp+seaweed), C (tiger shrimp+blood cockle), and D (tiger shrimp+seaweed+blood cockle). The data of tiger shrimp growth was monitored weekly, while the growth of blood cockle and seaweed was collected at the end of the study. The water quality parameters such as DO, pH, temperature, and salinity were monitored daily. Meanwhile, the data of Total organic matter (TOM), total ammonia nitrogen (TAN), NO2, and NO3 were measured weekly. The result of the research showed that the highest specific growth rate (SGR) was treatment D (5.75±0.03% day-1). While the highest SR value was treatment B 90.33±0.58%. However, survival rate (SR) on treatment B did not have a significant difference (p<0.05) with treatment C and D. In general, there was significant interaction (p<0.01) in organic waste parameters (TOM, TAN, NO2, and NO3) for all treatments. In removal rate (RR), treatment D was more effective in reducing TOM (19,20%). Meanwhile, the highest level of TAN reduction was achieved by treatment C (50%). In addition, the highest reduction in nitrite and nitrate variables was in treatment D (40% and 33,33%). In contrast, treatment A got a negative removal rate in all parameters.

Integration of multitrophic aquaculture approach with marine energy projects for management and restoration of coastal ecosystems of India

Coastal areas of India have a big potential for establishing renewable energy projects, which are generally regarded as green energy sources. However, such projects' construction work may cause a negative environmental impact on the surrounding waters. Aquaculture projects based on seaweed and fisheries, commonly referred to as integrated multitrophic aquaculture (IMTA), can help to mitigate these impacts. Although the purpose of any IMTA is to recirculate the waste products from cultivated species and not to mitigate the environmental impacts of energy projects, IMTA may serve as a complementary activity to compensate for the environmental impacts of marine energy projects. In return, marine energy projects can provide a few facilities to IMTA projects in their areas. IMTA projects are already practised in some parts of the world; however, rare examples are available with marine energy projects. This study aims to put an idea of potential IMTA projects in the areas of the proposed first offshore wind farm in India. This study also recommends the possible utilisation of the potential tidal energy plant in the estuary as a nursery for a few species in IMTA on the western coast of India. In addition, the current study discussed some major challenges, such as seasonal variations, ecological risks, selection of IMTA components, legal, economic and regulatory and social acceptance. Overcoming these challenges can promote further development of IMTA projects in Indian coastal waters.

Culturing the sea cucumber Holothuria poli in open-water integrated multi-trophic aquaculture at a coastal Mediterranean fish farm

The survival and growth of the sea cucumber Holothuria poli were assessed during a 12-month field study when cultured at a commercial fish farm in Malta as part of an integrated multi-trophic aquaculture (IMTA) system. Sea cucumbers were cultured directly below a fish cage at 0 m, E0, at 10 m (E10) and 25 m (E25) distances from the cage and at two reference sites (R1 and R2) located over 800 m away from the fish farm. Mass mortalities were recorded at E0 within the first month of the study due to smothering by settled wastes. All individuals died at one of the reference sites, R1, by the end of the study. After deducting missing sea cucumbers, survival rates at E10 (23%) and E25 (33%) from the fish cage were similar to the remaining reference site (R2) (27%). Stocking density and physical disturbances to the sea cucumber cage setup were also probable cause for the low survival rates. The relative weight gain (RWG) and specific growth rates (SGR) of H. poli varied significantly between sites close to the fish farm and the reference site. The SGR of H. poli at E10 (0.18 ± 0.02% day−1) and E25 (0.20 ± 0.01% day−1) was positive over the whole study period while no average growth was recorded at the reference site (−0.04 ± 0.07% day−1) over the same period. Differences in RWG and SGR were recorded throughout the study. The overall growth observed in H. poli by January was followed by a drop in growth rate across all sites and an increase in SGR at E25 in July. Slower growth rates were observed as water temperature approached 15 °C. The results indicated that the sediments near the commercial fish cage provided an enriched source of food that supported significantly better growth in H. poli. This suggests that H. poli in IMTA might have the potential to uptake organic farm waste and increase aquaculture production, albeit with important considerations for setup design and stocking density.

Diversity and fluctuation of cultivable Vibrio bacteria populations in an integrated multi-trophic aquaculture (IMTA) system of Holothuria scabra, Chanos chanos and Gracillaria sp

Sea cucumber is one of the vital aquaculture commodities in the global market. Progressive demand and limiting the supply of sea cucumber from natural sources drove sea cucumber aquaculture development. An integrated multi-trophic aquaculture system (IMTA) was a polyculture system in aquaculture to improve production by promoting nutrient utilisation through different tropical levels. This system combined sea cucumber (Holothuria scabra), milkfish (Chanos chanos), and seaweed (Gracillaria sp.) in a rearing tank system. Several factors affect the success of IMTA processes, including microorganisms. Microorganisms in the aquaculture environment play a crucial role in elements cycling, energy flow and farmed-species health. Diseases caused by the bacteria, mainly from the Vibrionaceae family, were often chronic than acute and may cause a high mortality percentage. This study aimed to investigate the Vibrio bacterial diversity and fluctuation in the water of IMTA rearing tanks. The result indicated that the Vibrio bacterial diversity from the polyculture system (IMTA) was generally higher than the monoculture system. Vibrio bacteria populations from different culture systems have been found to consist of varied bacterial species. However, the predominant species was the same. The polyculture system is suggested as a sustainable and eco-friendly culture system.

Mariculture Development in India: Status and Way Forward

Mariculture has immense potential in India in the context of fast-growing demand for seafood, which cannot be met by capture fisheries sector alone. Mariculture can also play an important role in increasing fish production from the coastal and offshore waters by involving local fishers and entrepreneurs to take up the activity. The pioneering attempts for mariculture development in the country by ICAR-Central Marine Fisheries Research Institute (CMFRI) on seed production and farming of finfishes such as cobia, silver pompano, Indian pompano, sea bass, groupers, snappers, breams and ornamental fishes, shell fishes such as molluscs, marine pearl production and seaweed farming, sea-cage farming, Integrated Multitrophic Aquaculture (IMTA). Recirculating Aquaculture System (RAS) and aquatic animal health management are highlighted and suggested strategies for way forward.

Widening the Horizon of Asian Mariculture with IMTA

Integrated multi-trophic aquaculture (IMTA) expands the benefits from farming the coastal and marine waters. The benefits, achieved and enhanced by synergy among the farmed species, are environmentally sustainable, economically stable and socially acceptable. To broadly illustrate, environmental sustainability is achieved through the bio-mitigation effect of the extractive species in the mix, economic stability through product diversification and the reduction of production and market risks from such diversification, and social acceptability through environmentally and socially responsible practices. A likely outcome is better market access and price of the products enabled by the favorable attitude of consumers towards the practices of IMTA and their willingness to pay a premium price for its products. The specific benefits are described in greater detail in the review of several IMTA systems in marine and coastal environments that have been tried in a number of Asian countries, namely, China, India, Indonesia, The Philippines, Thailand and Vietnam. The challenges to their adoption are identified and policies suggested to facilitate their diffusion and adoption.

Effective and Low-Maintenance IMTA System as Effluent Treatment Unit for Promoting Sustainability in Coastal Aquaculture

Integrated multitrophic aquaculture (IMTA) is a versatile technology emerging as an ecological and sustainable solution for traditional monoculture aquacultures in terms of effluent treatment. Nevertheless, IMTA is still poorly applied in aquaculture industry due to, among other reasons, the lack of effective, low-investment and low-maintenance solutions. In this study, one has developed a practical and low maintenance IMTA-pilot system, settled in a semi-intensive coastal aquaculture. The optimisation and performance of the system was validated using Ulva spp., a macroalgae that naturally grows in the fishponds of the local aquaculture. Several cultivation experiments were performed at lab-scale and in the IMTA-pilot system, in static mode. The specific growth rate (SGR), yield, nutrient removal, N and C enrichment, protein and pigment content were monitored. Ulva spp. successfully thrived in effluent from the fish species sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) production tanks and significantly reduced inorganic nutrient load in the effluent, particularly, NH4+, PO43− and NO3−. The enrichment of nitrogen in Ulva spp.’s tissues indicated nitrogen assimilation by the algae, though, the cultivated Ulva spp. showed lower amounts of protein and pigments in comparison to the wild type. This study indicates that the designed IMTA-pilot system is an efficient solution for fish effluent treatment and Ulva spp., a suitable effluent remediator.

Growth and Absorption Response of Perna viridis (Lin, 1758) To Fish Farm Water Quality in Valladolid

The extractive species, Perna viridis has been integrated into the existing commercial finfish culture of Chanos chanos and Trachinotus blochii in Valladolid, Carcar Bay, Eastern Cebu, Philippines, following the Integrated Multitrophic Aquaculture (IMTA) concept.

Environmental Management of Fish Cage Aquaculture

Most modern fish culture involves the intensive input of nutrients in the form of feed, yet only a small proportion of these nutrients is converted into the target product; they can be largely lost to bacterial degradation. However, when compared with other livestock production systems, aquaculture has better feed conversion efficiency and feed conversion ratios (FCRs) are continuing to improve. High levels of nutrients from fish cages may cause eutrophication and thus may affect fisheries adversely, but on the contrary, the additional nutrients from the feed may have a beneficial effect, boosting natural productivity including fisheries. The important components of fish farming waste comprise nutrients (dissolved and particulate) resulting from the metabolism of fish food, uneaten food, escapees of farmed fish affecting the genetic diversity of wild fish populations and chemical residues of disease or parasitic therapeutant treatments. Potential management measures to mitigate environmental impacts include public and private sector approaches. The public sector approaches include appropriate and specific aquaculture policies, strategies, regulations, legislation, and management plans, adoption and implementation of the FAO Code of Conduct for Responsible Fisheries (CCRF) and Ecosystem Approach to Aquaculture (EAA) strategies for planning, management, monitoring, and control. Zoning for aquaculture space is to be based on the allocation of aquafarms on suitable areas, appropriate evaluation of carrying capacity of the ecosystem, planning and management for disease prevention and treatment and environmental control. Appropriate control of farm permits, licences, and registration by the state is necessary to monitor and control aquaculture development. The private sector approaches include improved feed formulation and feeding strategies to reduce the feed conversion ratio and nutrient losses, the use of Integrated Multi-trophic Aquaculture (IMTA) to utilise nutrient outputs from intensive aquaculture and thus regular environmental monitoring is the key to ensure that impacts remain within acceptable limits.

Growth, nitrate uptake kinetics, and biofiltration potential of eucheumatoids with different thallus morphologies.

The declining production of commercially important eucheumatoids related to serious problems, like increasing susceptibility to ice-ice disease and epiphytism, may be ameliorated by nutrition. This ushered an increasing interest in incorporating seaweeds into an integrated multi-trophic aquaculture (IMTA) setup to take up excess inorganic nutrients produced by fish farms for their nourishment. In this regard, it is important to understand the nutrient uptake capacity of candidate seaweeds for incorporation into an IMTA system. Here, we examined the growth, nitrate ( ) uptake kinetics, and biofiltration potential of Eucheuma denticulatum and three strains of Kappaphycus alvarezii (G-O2, TR-C16, and SW-13) with distinct thallus morphologies. The uptake rates of the samples were determined under a range of concentrations (1-48 µM) and uptake rates were fitted to the Michaelis-Menten saturation equation. Among the examined eucheumatoids, only SW-13 had a linear response to concentration while other strains had uptake rates that followed the Michaelis-Menten saturation equation. Eucheuma denticulatum had the lowest Km (9.78 ± 1.48 µM) while G-O2 had the highest Vmax (307 ± 79.3 µmol · g-1 · min-1 ). The efficiency in uptake (highest Vmax /Km and α) was translated into the highest growth rate (3.41 ± 0.58% · d-1 ) measured in E. denticulatum. Our study provided evidence that eucheumatoids could potentially take up large amount of and fix CO2 when cultivated proximate to a fish farm as one component of an IMTA system. During a 45 -d cultivation period of eucheumatoids, as much as 370 g can be sequestered by every 1 kg initial biomass of E. denticulatum growing at 3% · d-1 . Furthermore, based on our unpublished photosynthetic measurements, the congeneric K. striatus can fix 27.5 g C · kg-1 DW during a 12 h daylight period.

A Multi-Species Investigation of Sponges' Filtering Activity towards Marine Microalgae.

Chronic discharge of surplus organic matter is a typical side effect of fish aquaculture, occasionally leading to coastal eutrophication and excessive phytoplankton growth. Owing to their innate filter-feeding capacity, marine sponges could mitigate environmental impact under integrated multitrophic aquaculture (IMTA) scenarios. Herein, we investigated the clearance capacity of four ubiquitous Mediterranean sponges (Agelas oroides, Axinella cannabina, Chondrosia reniformis and Sarcotragus foetidus) against three microalgal substrates with different size/motility characteristics: the nanophytoplankton Nannochloropsis sp. (~3.2 μm, nonmotile) and Isochrysis sp. (~3.8 μm, motile), as well as the diatom Phaeodactylum tricornutum (~21.7 μm, nonmotile). In vitro cleaning experiments were conducted using sponge explants in 1 L of natural seawater and applying different microalgal cell concentrations under light/dark conditions. The investigated sponges exhibited a wide range of retention efficiencies for the different phytoplankton cells, with the lowest average values found for A. cannabina (37%) and the highest for A. oroides (70%). The latter could filter up to 14.1 mL seawater per hour and gram of sponge wet weight, by retaining 100% of Isochrysis at a density of 105 cells mL−1, under darkness. Our results highlight differences in filtering capacity among sponge species and preferences for microalgal substrates with distinct size and motility traits.

Nutrient retention efficiencies in integrated multi‐trophic aquaculture

AbstractOne of the bottlenecks for commercial implementation of integrated multi‐trophic aquaculture (IMTA) is the difficulty in quantifying its environmental performance. We reviewed a large body of literature to determine the variability in nutrient dynamics within different IMTA systems (open sea‐cages, land‐based flow‐through and recirculating aquaculture systems), with the aim to provide a generic framework to quantify nutrient retention efficiencies in integrated aquaculture systems. Based on the eco‐physiological requirements of the cultured species, as well as the response of “extractive” species to waste from “fed” species, the maximum retention efficiency was defined for a conceptual four‐species marine IMTA system (fish–seaweed–bivalve–deposit feeder). This demonstrated that 79%–94% of nitrogen, phosphorus and carbon supplied with fish feed could theoretically be retained. In practice, however, various biological and environmental factors may limit retention efficiencies and thereby influence the bioremediation of IMTA systems. These biological (waste production, stoichiometry in nutrient requirements) and environmental (temporal and spatial connectivity) factors were therefore evaluated against the theoretical reference frame and showed that efficiencies of 45%–75% for closed systems and 40%–50% for open systems are more realistic. This study is thereby the first to provide quantitative estimates for nutrient retention across IMTA systems, demonstrating that a substantial fraction of nutrients released from fish culture units can be retained by extractive species and subsequently harvested. Furthermore, by adapting this framework to the design and the condition prevailing for a specific IMTA system, it becomes a generic tool to analyse the system's bioremediation potential and explore options for further improvement.

Co-cultivation with blue mussels increases yield and biomass quality of kelp

Integrated multi-trophic aquaculture (IMTA) has to date largely centred on a fed species, often finfish or shrimps, alongside which extractive species, such as bivalves or seaweeds, have been placed. In comparison, IMTA systems excluding a fed component have received little research. Here we report a field study of an IMTA cultivation of the sugar kelp, Saccharina latissima, and the blue mussel, Mytilus edulis, on the Swedish west coast. Kelp were cultivated at two depths, 1-2 m and 3-4 m, either 10 m downstream of commercial scale blue mussel farms, or at control (monoculture) sites at least 500 m from the nearest farm. Significant enhancement of kelp yields in terms of both blade length and biomass was observed in IMTA treatments compared to monoculture, with a mean increase in length of 22% and biomass of 38%. Moreover, kelps co-cultivated with mussels displayed an epiphyte reduction of more than half compared to kelps grown in monoculture, with a 15% coverage in monoculture compared to 6% in co-culture. Significant increases in pigment content were also detected, with higher levels of chlorophyll a, fucoxanthin and phaeophytin in IMTA treatment kelps in comparison to monoculture. This study provides evidence for the potential of IMTA systems containing solely extractive species and presents factors beyond nutrient enrichment as drivers for enhanced growth in these systems.

Halophyte Plants Cultured in Aquaponics Hold the Same Potential for Valorization as Wild Conspecifics from Donor Sites

Halophytes have gradually been introduced in marine integrated multi-trophic aquaculture (IMTA) systems due to their capacity to bioremediate nutrient-rich marine effluents and their potential use for human consumption due to their content of omega-3 and omega-6 fatty acids (FA). To foster the valorization of halophytes produced using an IMTA framework for human consumption, it is important that culture conditions keep or enhance their FA profile, when compared to that displayed by conspecifics in the wild. The main objective of the present study was to compare the FA profiles of three halophyte species (Halimione portulacoides, Salicornia ramosissima and Sarcocornia perennis) cultured in aquaponics coupled to an IMTA system with that of wild conspecifics retrieved from donor sites. The FA profiles were compared considering different plant organs (edible parts and roots) and sampling dates (spring, summer and autumn). Results show that the FA profiles of specimens cultured in aquaponics were significantly different from that of wild conspecifics, displaying a high content of omega-3 FAs in edible parts, particularly during summer, and mostly in the form of α-linolenic acid (ALA, 18:3n-3). In more detail, for the specimens cultured in aquaponics, ALA concentration in the edible parts of each species ranged from 5.10 to 7.11 μg mg−1 DW in H. portulacoides, from 5.66 to 9.19 μg mg−1 DW in S. ramosissima and from 5.49 to 7.20 μg mg−1 DW in S. perennis. Concerning the omega-6 linoleic acid (LA, 18:2n-6) identified in edible parts, the concentrations ranged from 2.25 to 2.46 μg mg−1 DW in H. portulacoides, from 3.26 to 4.84 μg mg−1 DW in S. ramosissima, and from 2.17 to 3.06 μg mg−1 DW in S. perennis. The nutritional quality was assessed through the ratio of PUFA/SFA, for both wild and cultured plants, and revealed values well above the threshold (0.45), the threshold value indicative of good nutritional quality. Overall, the culture conditions tested in the present work reinforce the potential of aquaponics coupled to marine IMTA to produce high-quality halophytes suitable for human consumption.

Sustainable aquafeed and aquaculture production systems as impacted by challenges of global food security and climate change

Sustainable aquafeed and aquaculture production systems as impacted by challenges of global food security and climate change

Cumulative climatic stressors strangles marine aquaculture: Ancillary effects of COVID 19 on Spanish mariculture

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.

The application of integrated multi-trophic aquaculture (IMTA) using floating net cages on Tilapia fish with native fish (Peres, Lemeduk, and Depik)

Environmental problems due to aquaculture occur along with the increase in aquaculture production. IMTA is one system used as a solution in dealing with environmental problems. The objective of this study was to analyze the growth performance, survival rate, and production of the main commodity (tilapia) and the supporting commodities (Peres, Lemeduk, and Depik) which are applied through the application of integrated multi-trophic aquaculture (IMTA) using floating net cages. This research was conducted at the Lukup Badak Fish Seed Center, Central Aceh from July to August 2020. The experimental design used was a completely randomized design (CRD) with 4 treatments and 3 replications, namely: A (tilapia), B (tilapia and peres), C (tilapia and lemeduk), and D (tilapia and depik). ANOVA test results showed that the IMTA system had a significant effect on absolute length growth, absolute weight growth, specific growth rate (SGR), survival rate, and biomass production of tilapia (P0.05). The results showed that maintenance for 42 days produced the highest value in treatment B with the increase in absolute length growth (4.26cm±0.24); absolute weight growth (5.47g±0.45), specific daily growth rate (2.28%/day±0.13) and the highest tilapia biomass production (480g/0.5m2±19.25). The highest survival rate was found in treatment C (82.42%±2.28). It was concluded that the treatment using the IMTA system was better than without the IMTA system.Keywords:IMTAWater qualityGrowth performanceTrophic interactionBiomass production