Effect of density of fingerling and juvenile pirarucu during transportation on water quality and physiological parameters

Abstract

We assessed the effect of stocking density on physiological parameters (blood lactate, glucose, cortisol, hematocrit), water quality (temperature, dissolved oxygen, pH, unionized ammonia, carbon dioxide), and survival during the transportation of fingerling (24.5 ± 4.7 g) and juvenile (615.8 ± 122.2 g) pirarucu (Arapaima gigas) for six hours in plastic bags. The tested densities were 65, 80, 95, 110 and 125 g L-1 for fingerlings, and 50, 80, 110, 140 and 170 g L-1 for juveniles (three replicates each). Parameters were measured prior to and immediately after transportation, and at 24 and 96 hours recovery after transportation. No mortality was observed, except for fingerlings (< 3%) at densities of 110 and 125 g L-1 during recovery. All the water quality parameters were significantly altered after the transportation of fingerlings and juveniles. Water temperature, dissolved oxygen, carbon dioxide and unionized ammonia increased, but pH decreased. Only carbon dioxide and unionized ammonia differed among densities. Cortisol levels did not increase over time, except for the juveniles at 170 g L-1, which still had high cortisol after 96 hours. Glucose significantly increased after transportation for all the treatments and returned to the initial values during the recovery period. Conversely, the lactate values were still high after 96 hours. Hematocrit was assessed only for juveniles and was significantly lower after transportation. We conclude that fingerling and juvenile pirarucu can be safely transported at densities up to 95 g L-1 and 140 g L-1, respectively.

Knowledge of, and Attitudes towards, Live Fish Transport among Aquaculture Industry Stakeholders in China: A Qualitative Study

“…Methods such as ice cooling are often used to reduce water temperature during live transport [ 45 ], and these are similarly noted in the current study - the reported addition of ice into water. Lower water temperatures can also help to maintain water quality during transport [ 9 ]. For example, in a previous study, ammonia nitrogen concentrations were lower when largemouth bronze gudgeons ( Coreius guichenoti ) were transported in cool water [ 32 ].…”

“…Live transport includes pre-transport procedures (grading, crowding, netting, fasting, handling, and loading/packing), during transport procedures, and post-transport processes (unloading and handling), which are potentially stressful to fish [ 6 , 7 ]. Common stressors associated with live transport are inappropriate handling, air exposure, food deprivation, poor water quality, inappropriate transport densities, sudden changes in water temperature, and rapid water movement [ 3 , 5 , 8 , 9 , 10 ]. It is challenging to maintain the health and well-being of live fish during transport, particularly because of the large numbers of animals in many varied transport situations.…”

Effect of stocking density in plastic boxes without oxygenation on the transport of pirarucu,Arapaima gigas (Schinz, 1822)

“…The plasma glucose of pirarucu was higher at the AT moment and followed by a reduction in the 24 h time, stabilizing in the 48 h time, suggesting the effect of secondary stress triggered at the moment AT. Lima et al (2020) also observed a significant increase in pirarucu glucose AT in all treatments, returning to baseline levels during the recovery period. Change in plasma glucose is a physiological response in many fish species and may increase or decrease, or remain constant after an increase in plasma cortisol (Mommsen et al, 1999).…”

“…In larger pirarucu (9 kg), as the stocking density increased during transport, the hematocrit increased with rising time (Lima & de Oliveira, 2017). In pirarucu juveniles (615.8 g), testing was done for transport in plastic bags and different densities, and the hematocrit was significantly lower AT at a density of up to 140 g L À1 (Lima et al, 2020), showing that this secondary stress indicator varies according to the intensity of the stress suffered (Sampaio & Freire, 2016), and adequate transport can minimize stress during this management, while high fish density is important to reduce costs (de Abreu et al, 2008).…”

“…Gomes et al (2006) evaluated the effects of adding salt on the transport of juveniles (32.8 g) in plastic bags; Brandão et al (2008) addressed this same theme for 1.0 kg juveniles transported in an open-and-closed system; Lima and de Oliveira (2017), transporting juvenile arapaima (9.2 kg) at three different densities in an open system, observed that 9 kg pirarucu recovered well from stress when transported for up to 6 h at a loading density of 160 kg/m 3 . Lima et al (2020) tested transporting arapaima with two different age groups (24.5 and 615.8 g) for 6 h in plastic bags with different densities and observed that ideal densities according to age improved recovery after transport (AT) stress.…”