Abstract
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.
Highlights
Live fish transportation is a routine practice in fish farming that allows fish to be moved between production chain links
As pirarucu had increased blood glucose and lactate levels in all our treatments, but without high cortisol levels in most treatments, a secondary stress response was observed after transportation
The blood glucose levels returned to the initial values by 96 h, and the lower cortisol and lactate levels demonstrated how fast pirarucu can recover from a stressful situation
Summary
Live fish transportation is a routine practice in fish farming that allows fish to be moved between production chain links. Fish are simultaneously subject to several stressors, mainly long exposure to poor water quality and inappropriate stocking densities, and to poor handling, confinement and acclimation (Harmon 2009). These stressors, in conjunction with fish health status and the level of blood chemical changes, are the main factors to affect post-transportation survival (Berka 1986; Portz et al 2006). As closed systems offer no air or water exchanges, loading capacity is an important determinant for fish safety during transportation. There is pressure from the production sector for higher stocking densities to improve economic viability (Portz et al 2006; Carneiro et al 2009)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
