Effects of Fish Stocking Density on Water Quality, Growth Performance of Tilapia (Oreochromis niloticus) and Yield of Butterhead Lettuce (Lactuca sativa) Grown in Decoupled Recirculation Aquaponic Systems

Abstract

This study was conducted over a period of 52 days to determine the effects of fish stocking density on the water quality, growth performance of tilapia and yield of butterhead lettuce cultivated in decoupled recirculation aquaponic systems (DRAPS). In this study, three respective tilapia stocking densities (treatments) of 8 kg•m-3 , 10 kg•m-3 , and 12 kg•m-3 were used to evaluate the butterhead lettuce in the DRAPS, which consist of two independent loops. All treatments were done in triplicates. The results showed with increased stocking density, the electrical conductivity, total dissolved substances and salinity increased and dissolved oxygen decline. The results showed that the highest stocking density produced the highest nutrients accumulation of ammonia-nitrogen (NH 3-N), ammonium (NH 4), nitrite-nitrogen (NO 2-N) and nitrate-nitrogen (NO 3-N) and potassium (K) except for phosphorus (P). Nevertheless, based on the conversion of fish feed to NO 3-N and P per kilogram of feeds, the lowest stocking density provided the highest concentration of NO 3-N and P. It was documented that DRAPS relied solely on the fish waste produced an insufficient concentration of N, P, K and iron. The average survival rate of tilapia in all treatments was above 94% and was not a significant difference among the treatments.

Aquaponics as a Promising Strategy to Mitigate Impacts of Climate Change on Rainbow Trout Culture

“…Stocking density and fish species are key factors in aquaponics systems that can significantly affect plant yield and quality, aspects that both farmers and consumers need to be aware of [ 178 ]. According to several studies, different plants and fish will have different optimal ratios and largely depend on factors, such as fish stocking density, aquaponics type, plant species, planting density, hydroponic or soil crop production system type, water flow rate, and external factors [ 179 ]. Therefore, the density of plants that will be grown in a system of aquaponics depends on the species and the density of the fish [ 180 ].…”

Yield and Nutrients Leaf Content of Butterhead Lettuce <i>(Lactuca Sativa)</i> in Response to Fish Nutrient Solution in a Small Scale of Aquaponic Systems

“…Aquaponics system (APS) plays an influential and significant role in improving sustainable food production in the future (Goddek et al, 2016) by providing sufficient plant and fish products (Rakocy et al, 2006) for human consumption, which has a direct impact on the future of global food security. Aquaponics combines RAS with soilless culture systems through the nitrification process to produce a non-toxic form of nitrate (NO 3 -N) as the final product of nitrogen (N) (Rakocy et al, 2006;Al Tawaha et al, 2021). This system was one of the fastestgrowing agricultural food production systems (Rakocy et al, 2006; Graber and Junge 2009; Rakocy 2012; Somerville et al, 2014).…”

“…Stocking density (SD) is a crucial factor in DRAPS with a high planting density. It affects the productivity of macronutrients through the biological process such as NO 3 -N, P and K, which is required for plant growth and development (Al- Tawaha et al, 2021). Furthermore, a high stocking density affects the water quality parameters of a small-scale APS by reducing the DO and increasing the NH 3 -N, NO 3 -N, total suspended solids, salinity, and EC (Al- Tawaha et al, 2021).…”

“…It affects the productivity of macronutrients through the biological process such as NO 3 -N, P and K, which is required for plant growth and development (Al- Tawaha et al, 2021). Furthermore, a high stocking density affects the water quality parameters of a small-scale APS by reducing the DO and increasing the NH 3 -N, NO 3 -N, total suspended solids, salinity, and EC (Al- Tawaha et al, 2021). Hence, if the stocking density of a DRAPS is high, the conditions such as the surface area of biofilter materials, size ratio of the rearing tank Yield and Nutrients Leaf Content of Butterhead Lettuce (Lactuca Sativa) in Response to Fish Nutrient Solution in a Small Scale of Aquaponic Systems to biological tank, and the efficiency of the mechanical filter need to be optimized to have a high amount of nitrifying bacteria in the system.…”

“…As a result, tilapia culture has been practiced widely to reduce the rising worldwide demands for protein sources and its high economic value (Diver, 2006). Therefore, the success of the symbiotic integration of tilapia and lettuce in APS has a significant role in sustaining the agriculture production system (Tyson et al, 2011;Effendi et al, 2017;Al Tawaha et al, 2021). In APS, SD is a vital factor in maintaining water quality for growth and yield for fish and plants.…”