Plasma Cortisol and Chloride Stress Responses in Juvenile Walleyes during Capture, Transport, and Stocking Procedures

Abstract

Extensively reared juvenile walleyes Stizostedion vitreum subjected to capture and transport stressors associated with stocking procedures in South Dakota and Minnesota displayed acute increases in plasma cortisol and extended declines in concentrations of plasma chloride. In four separate South Dakota transport hauls, mean plasma cortisol in walleyes rose from 12–49 ng/mL at the time of trap‐net capture to 138–174 ng/mL after 1 h of transport; these concentrations remained increased at 3 h. Plasma chloride decreased by about 19% during this period; by 3 h, mean values had dropped about 30%, to 53–61 meq/L. Similarly, in Minnesota mean plasma cortisol in captured and transported walleyes increased from 13–26 ng/mL during trap‐net capture to 154–214 ng/mL by 1 h after transport in three separate trials and remained at the higher values at 3 h posttransport. Mean plasma chloride concentrations dropped about 28%, to 65–72 meq/L, by 3 h after transport and remained significantly decreased at 68–82 meq/L 24 h later, even though plasma cortisol, an acute stress indicator, had returned to near pretransport values. Results from these experimental transport hauls indicate that the juvenile walleyes experienced considerable physiological stress when captured and transported to lakes for stocking. This stress was reflected by an appreciable decrease in plasma chloride that failed to recover to pretransport values after 24 h, which suggests a possible mechanism for poststocking mortality.

Stress responses of juvenile matrinxã (Brycon amazonicus) after transport in a closed system under different loading densities

“…The highest values of osmolality were verified 24h AT and may be related to the feeding that was normalized at that time. Similar ionic response was reported in other transported fish (CARMICHAEL 1984;BARTON et al, 2003), but a simulation of high-density transport did not cause any serious osmoregulatory disturbance in Atlantic cod (Gadus morhua) until 24h after the stressor (STAURNES et al, 1994).…”

Transport of jundiá Rhamdia quelen juveniles at different loading densities: water quality and blood parameters

“…Plasma chloride levels were within the range normally found for this species under minimized stress conditions (118-132 mEq L -1 ); whereas hematocrit exhibited lower values (range for jundiá under minimum stress: 37-51%), according to Borges et al (2004). In contrast to what was observed by Gomes et al (2006) with pirarucu (Arapaima gigas), by Barton et al (2003) with walleye (Stizostedion vitreum) and by Carneiro & Urbinati (2001) and with matrinxã (Brycon cephalus), the plasma chloride and hematocrit analyses did not show results that permitted evaluation of the physiological state of jundiá under the acute stress caused by loading density or transport itself.…”

Capture, adaptation and artificial control of reproduction of Lophiosilurus alexandri: A carnivorous freshwater species

“…However, the task of adapting wild broodstock to laboratory conditions involves many processes, ranging from capture, transport, acclimation and maintenance of the animals in captivity (Moorhead and Zeng, 2010;Maricchiolo et al, 2014). Improper management of these actions may result in gonadal atresia and even lead to mortality of captured animals as a result of the stress response (Barton et al, 2003;Ashley, 2007;Murchie et al, 2009). Breeding in captivity also requires the study of reproductive biology of the species and the development of strategies for maintaining animals in confined conditions (Hunting Ford, 2004;Pankhurst and Fitzgibbon, 2006;Moorhead and Zeng, 2011).…”