Effects of the fish species choice on vegetables in aquaponics under spring-summer conditions in northern Germany (Mecklenburg Western Pomerania)

Autor: Knaus, U.; Palm, H.W. 2017b
In:

Aquaculture

Bandangabe: 473
ISBN: 0044-8486
DOI: doi:10.1016/j.aquaculture.2017.01.020
Seite: 62 - 73
Jahr: 2017

Einordung:
Institut: Professur Aquakultur und Sea-Ranching

Abstract:
The effect of juvenile Nile tilapia (Oreochromis niloticus, in unit I) and Common carp (Cyprinus carpio, in unit II) on plant growth (cucumber - Cucumis sativus, tomato - Solanum lycopersicum and lettuce - Lactuca sativa in co-cultivation)
was investigated in two identical gravel substrate ebb-and-flood coupled aquaponic units (I, II) with 3.81 m3 total water volume and without addition of fertiliser for 70 days. The daily extruded floating feed input of 1.2% (200 g) of initial fish biomass (16.7 kg) per unit equalled 12.0 g feed per kg fish or 52.5 g m−3.
Growth of O. niloticus (unit I) was better (p b 0.05) in final weight (57.4 g ± 27.9), final biomass (27,683.3 g ± 160.7), specific growth rate (0.70% d−1 ± 0.01) and feed conversion ratio (1.31 ± 0.02) in comparison to C. carpio (unit II, 42.7 g±22.2, 21,866.7 g±568.6, 0.39% d−1±0.02, 2.69±0.20). Tomato gross biomass
was two times higher in combination with O. niloticus and tomato fruit weight was slightly higher. Plant growth in cucumber showed higher total fresh biomass in the C. carpio unit. Lettuce yieldwas near zero as a result
of inter-specific competition. The Aquaponic Growth Factor (AGF), describing the growth performance of fish and plant combinations, was highest in tomato (1.12) combined with O. niloticus compared with C. Carpio (0.53). However, the AGF of cucumber was slightly higher in combination with C. carpio (0.14) compared with
O. niloticus (0.12). This study demonstrates best plant growth for the combination of O. niloticus with tomato and C. carpio with cucumber. The unit stocked with C. carpio had higher levels of oxygen (6.3 mg L−1 ± 0.8)and oxygen saturation (78.6% ± 8.4) in contrast to O. niloticus (5.8 mg L−1 ± 0.8, 73.2% ± 8.9). The long steady
state of dissolved oxygen inside both units allowed a higher daily feed input of 0.3% of fish initial biomass during spring and summer seasons, 25% above the optimal feed input estimated for the same units during winter time (0.9% = 150 g). C. carpio extended the equilibrium phase during plant production before a significant oxygen
drop occurred, beneficial for coupled aquaponics. Different growth performance of fish and plant combinations suggest multiple fish species use or polyponics (polyculture + aquaponics) in coupled aquaponics to increase plant yield.

Ansprechpartner

Weitere Information im WWW

Zur Publikation: Mitarbeiter, Projekte
Weitere Publikationen im Forschungsteilschwerpunkt