Effect of plant density in coupled aquaponics on the welfare status of African catfish, Clarias gariepinus. Issue 1 (4th November 2018)

• Record Type: Journal Article
• Authors: Baßmann, Björn; Harbach, Harvey; Weißbach, Stephan; Palm, Harry W.
• Is Part Of: Journal of the World Aquaculture Society. Volume 51:Issue 1(2020)
• Page Start: 183
• Page End: 199
• Publication Date: 2018-11-04
• Subjects: aquaponics -- basil -- behavior -- cortisol -- fish welfare -- induced stressor -- welfare evaluation (factor); Aquaculture -- Periodicals; 639.8
• DOI: 10.1111/jwas.12574
• Languages: English
• ISSNs: 0893-8849

Abstract

Abstract : We investigated the effects of plant density on the welfare of African catfish, Clarias gariepinus, in coupled aquaponics over 85 days. The moderate density (mpd) of basil, Ocimum basilicum, was compared with the high density (hpd) and control ( n = 0). The behavior was analyzed by visual and video observations, and after the application of induced stressors, skin injuries, blood glucose, lactate, and plasma cortisol responses were considered. The hpd fish showed the least activity (control: visual 77.8%, video 81.6%; mpd: 74.6%, 82.6%; hpd: 63.2% [ p < 0.05], 78.8%). High agonistic behavior (control: 5, 131; mpd: 4, 57; hpd: 1, 45) and the highest number of injuries (control: 3.9; mpd: 2.9; hpd: 3.4) were observed in the control. Glucose and lactate levels did not differ significantly (control: 5.5, 2.6 mmol/L; mpd: 5.6, 2.7 mmol/L; hpd: 5.3, 2.6 mmol/L); however, cortisol levels did (control: 18.8 ng/mL, mpd: 19.9 ng/mL, hpd: 25.8 ng/mL). pH adjustment led to additional stress, resulting in temporal cortisol alterations. While in the control and mpd, low cortisol levels were followed by acute responses and downregulation, the hpd fish showed prior elevation and lagged an acute response. However, comparing injuries and behavioral patterns with control, aquaponics with high basil density influenced African catfish positively.