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Neori, A.; Guttman, L.; Israel, A., and Shpigel, M., 2019. Israeli-developed models of marine integrated multi trophic aquaculture (IMTA). In: Jithendran, K.P.; Saraswathy, R.; Balasubramanian, C.P.; Kumaraguru Vasagam, K.P.; Jayasankar, V.; Raghavan, R.; Alavandi, S.V., and Vijayan, K.K. (eds.), BRAQCON 2019: World Brackishwater Aquaculture Conference. Journal of Coastal Research, Special Issue No. 86, pp. 11–20. Coconut Creek (Florida), ISSN 0749-0208. Modern Israeli integrated multi-trophic aquaculture (IMTA) has emerged from the Israeli freshwater polyculture, with carps, tilapia and grey mullet that started in the 1940-1950s. The dynamics, processes, environment and management of semi-intensive (several tons ha-1 y-1) mariculture IMTA started in the early 1970s, at the National Center for Mariculture (NCM) in Eilat, with several models that combined flow-through and recirculation features between primary (fed) and secondary (extractive) species. The seawater fishponds differed from freshwater ponds mainly in the continuous exchange with water from the open sea, to stabilize salinity and other water quality features. The primary (fed) fish was mostly the seabream (Sparus aurata), seabass (Dicentrarchus labrax), shrimp (Penaeus semisulcatus) and mullets (Mugil cephalus and Liza ramada). At first, the extractive component included microalgae, oysters (Crassostrea gigas) and clams (Ruditapes philippnmarum). In more progressive models, plastic-lined double drain ponds and tanks are used. Several other species, for example: clams, seaweed (the macroalgae Ulva spp. and Gracilaria spp.), abalone (Haliotis tuberculata and H. discus hannai), sea urchins (Paracentrotus lividus and Tripneustes gratilla elatensis), shrimp, brine shrimp (Artemia salina) are used. Wetlands planted with the halophytes Salicornia sp. and Sarcocrnia sp. have been integrated as IMTA. Recently, periphyton and drip-irrigated algal biofilters were examined and found to be practical. The research contributed to the enhancement of the sustainability, flexibility and potential for profitability of the aquaculture operation, based on the accumulated understanding about the functioning of the different units and the interactions between them. The principles developed in this research are relevant to brackishwater aquaculture, and have been applied for shrimp culture, mainly in China. [ABSTRACT FROM AUTHOR]

Periphyton-based biofilters for aquaculture effluent possess multiple advantages, in water oxygenation, CO 2 reduction and production of useful biomass. The performance of a marine periphyton biofilter, in terms of uptake rate and efficiency in removing different forms of nitrogen, was investigated. A periphyton biofilter was paired with an upstream macroalgae biofilter stocked with Ulva to expose the periphyton to ammonia-depleted but nitrate-rich effluent. Three trials compared the removal of total ammonia-N (TAN), nitrate (NO 3 -N), total N and phosphorus. The biofiltration and growth performance of (1) the periphyton downstream to the Ulva tank, (2) periphyton alone and (3) Ulva alone were compared. Biofiltration performance was evaluated at different areal loads of TAN and NO 3 -N. Periphyton growth performance did not depend on the effluent nutrient composition or on N loads, and yielded between 7.3 and 10.6 g dry weight m −2  d −1 . While the Ulva preferred uptake of TAN over NO 3 -N, the periphyton showed no preference between them , demonstrating flexible shifts between TAN and NO 3 -N uptake. TAN uptake rate by the periphyton was not influenced by the effluent composition. However, periphyton NO 3 -N uptake rate and efficiency rose about fivefold, up to 1.4 g NO 3 -N m −2  d −1 and 63%, respectively, upon depletion of TAN areal load below 0.18 g N m −2  d −1 (<0.3 mg L −1 ) by the Ulva pre-treatment. Normalizing nutrient uptake rate to biomass revealed similar uptake rate of TAN and phosphorus by periphyton and Ulva , while the periphyton took up nitrate much faster. By removing up to 76% of the total nitrogen, with specific removal efficiency of 97% of the TAN and of 67% of the NO 3 -N, the novel dual Ulva -periphyton biofilter revealed a synergistic potential in treatment of nutrient-rich mariculture effluents. [ABSTRACT FROM AUTHOR]

A periphyton biofiltration system of mariculture effluents was studied to identify ecological processes and management procedures that strongly affect the biofilter functioning, in order to attain optimal biomass production and nutrient removal. The multivariate statistical technique of factor analysis allowed reducing the large amount of data available into three main factors. The first factor, which accounted for 49% of the overall data variability, was herein called "biological activity" as it represents the joint effects on the variables measured of photosynthesis, N and P uptake, respiration and decomposition of organic matter. The second and third factors were "autotrophic biomass density" and "nitrite and phosphate uptake/release balance", which, respectively, accounted for further 20% and 14% of the data variability. A conceptual model, describing the functioning of the periphyton biofilters, revealed a delicate equilibrium among the different processes, whose understanding help to manage the biofilters towards optimal production of periphytic biomass and nutrient removal. Raising flow rate raised the overall nutrient uptake rate but reduced uptake efficiency and diluted nitrifying particles. A reduced flow rate led to sedimentation of organic particles, decomposition and nutrients re-mineralization. Apparently, control of water flow and nutrient content, periphyton substrate area and the cleaning of the effluent supply system are key management elements for the operation of a periphyton-based biofilter system that maximizes both periphyton biomass production and nutrient removal. [ABSTRACT FROM AUTHOR]

The seaweed Ulva lactuca L. was spray cultured by mariculture effluents in a mattress-like layer, held in air on slanted boards by plastic netting. Air-agitated seaweed suspension tanks were the reference. Growth rate, yield, and ammonia-N removal rate were 11.8% · d−1, 171 g fresh weight (fwt) · m−2 · d−1, and 5 g N · m−2 · d−1, respectively, by the spray-cultured U. lactuca, and 16.9% · d−1, 283 g fwt · m−2 · d−1, and 7 g N · m−2 · d−1, respectively, by the tank U. lactuca. Biomass protein content was similar in both treatments. Dissolved oxygen in the fishpond effluent water was raised by >3 mg · L−1 and pH by up to half a unit, upon passage through both culture systems. The data suggest that spray-irrigation culture of U. lactuca in this simple green-mattress-like system supplies the seaweed all it needs to grow and biofilter at rates close to those in standard air-agitated tank culture. [ABSTRACT FROM AUTHOR]

Biofilters made of Ulva and periphyton differ in their effectiveness in removing ammonia and nitrate from mariculture effluents. Our research evaluated the practicality of a combination of these two biofilters in improving the overall removal of dissolved N, where efficient removal of ammonia by the seaweed is followed by efficient removal of nitrate by periphyton. A paired Ulva -periphyton biofilter was exposed to various areal loads of ammonia and nitrate, the primary nitrogen forms in fishpond effluents. A first upstream macroalgae biofilter stocked with Ulva was fed with fishpond effluents at different areal loads of ammonia and nitrate, while a second downstream periphyton biofilter was paired for further nitrogen removal from the effluent. Ulva removed ammonia at a rate of 0.7–5.4 g TAN m−2 d−1, in correlation with the TAN areal load, with V max of 5.1 and K m of 4.4 g TAN m−2 d−1. Downstream periphyton was exposed to a lower TAN, but nitrate-rich effluent, and revealed similar capacities for the removal of both N forms, at removal rates of up to 1.7 and 1.8 g N m−2 d−1, respectively. Compared to nitrate, areal load of TAN had a greater impact on the removal dynamics of both N forms by periphyton. Overall, the paired biofilter resulted in a nearly total depletion of ammonia (97%) and efficient nitrate removal (67%), when areal loads in fishpond effluents were below 2 and 4 g N m−2 d−1 of TAN and NO 3 -N, respectively. • Ulva- periphyton biofilter removed 97% of TAN & 67% of NO 3 -N in fishponds effluent. • <2 g TAN and 4 g NO 3 -N (m−2 d−1) in effluent resulted with maximal removal. • Ulva removed TAN in correlation with areal load of this nutrient. • Periphyton revealed similar capacities for the removal of TAN and NO 3 -N. • Areal load of TAN had great impact on periphyton removal dynamics of TAN & NO 3 -N. [ABSTRACT FROM AUTHOR]