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The osmorespiratory compromise in sculpins: Impaired gas exchange is associated with freshwater tolerance

Henriksson, Patrik LU ; Mandic, Milica and Richards, Jeffrey G. (2008) In Physiological and Biochemical Zoology 81(3). p.310-319
Abstract
We acclimated two species of sculpin, the freshwater prickly sculpin (Cottus asper) and the closely related marine Pacific staghorn sculpin (Leptocottus armatus) to freshwater (similar to 0 g/L), brackish water (15 g/L), and seawater (30 g/L) for at least 4 wk and examined the relationships between respiration, ion regulation, gill morphology, and freshwater tolerance. The prickly sculpin successfully acclimated to all three salinities and did not experience appreciable changes in plasma osmolality, [Cl-], or mortality. Gill Na+/K+-ATPase activity was lowest in prickly sculpins acclimated to freshwater, their native salinity, and increased during acclimation to seawater. Furthermore, prickly sculpins acclimated to freshwater had a 30%... (More)
We acclimated two species of sculpin, the freshwater prickly sculpin (Cottus asper) and the closely related marine Pacific staghorn sculpin (Leptocottus armatus) to freshwater (similar to 0 g/L), brackish water (15 g/L), and seawater (30 g/L) for at least 4 wk and examined the relationships between respiration, ion regulation, gill morphology, and freshwater tolerance. The prickly sculpin successfully acclimated to all three salinities and did not experience appreciable changes in plasma osmolality, [Cl-], or mortality. Gill Na+/K+-ATPase activity was lowest in prickly sculpins acclimated to freshwater, their native salinity, and increased during acclimation to seawater. Furthermore, prickly sculpins acclimated to freshwater had a 30% higher P-crit than fish acclimated to brackish water or seawater; Pcrit is the environmental Po-2 below which an animal can no longer maintain a routine Mo-2, and an increase in P-crit represents a compromise of respiratory gas exchange. The higher Pcrit observed in prickly sculpins acclimated to freshwater is likely a consequence of their having small, relatively thick gills that increase in thickness (by similar to 1 mu m) during freshwater exposure. In contrast, the marine Pacific staghorn sculpin successfully acclimated to brackish water and seawater, but high mortality (25%) was observed after 3 wk of exposure to freshwater. Pacific staghorn sculpins exposed to freshwater suffered significant, 15%-20%, reductions in plasma osmolality and [Cl-], and these losses in plasma ions resulted in a 1.4-fold increase in gill Na+/K+-ATPase activity. Pacific staghorn sculpins have large, thin gills that are not modified in response to salinity acclimation, and as a result, these animals show no respiratory compromise during freshwater acclimation, as evidenced by the lack of change in Pcrit, but show significant ion regulatory disturbance. Overall, this study suggests that gill thickening and the resulting respiratory compromise are necessary for freshwater tolerance in sculpins. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physiological and Biochemical Zoology
volume
81
issue
3
pages
310 - 319
publisher
University of Chicago Press
external identifiers
  • wos:000254577000007
  • scopus:42649086164
ISSN
1522-2152
DOI
10.1086/587092
language
English
LU publication?
yes
id
be84887a-3772-41bf-8458-d65838b97a34 (old id 1207377)
date added to LUP
2008-08-28 12:47:06
date last changed
2017-01-22 03:21:37
@article{be84887a-3772-41bf-8458-d65838b97a34,
  abstract     = {We acclimated two species of sculpin, the freshwater prickly sculpin (Cottus asper) and the closely related marine Pacific staghorn sculpin (Leptocottus armatus) to freshwater (similar to 0 g/L), brackish water (15 g/L), and seawater (30 g/L) for at least 4 wk and examined the relationships between respiration, ion regulation, gill morphology, and freshwater tolerance. The prickly sculpin successfully acclimated to all three salinities and did not experience appreciable changes in plasma osmolality, [Cl-], or mortality. Gill Na+/K+-ATPase activity was lowest in prickly sculpins acclimated to freshwater, their native salinity, and increased during acclimation to seawater. Furthermore, prickly sculpins acclimated to freshwater had a 30% higher P-crit than fish acclimated to brackish water or seawater; Pcrit is the environmental Po-2 below which an animal can no longer maintain a routine Mo-2, and an increase in P-crit represents a compromise of respiratory gas exchange. The higher Pcrit observed in prickly sculpins acclimated to freshwater is likely a consequence of their having small, relatively thick gills that increase in thickness (by similar to 1 mu m) during freshwater exposure. In contrast, the marine Pacific staghorn sculpin successfully acclimated to brackish water and seawater, but high mortality (25%) was observed after 3 wk of exposure to freshwater. Pacific staghorn sculpins exposed to freshwater suffered significant, 15%-20%, reductions in plasma osmolality and [Cl-], and these losses in plasma ions resulted in a 1.4-fold increase in gill Na+/K+-ATPase activity. Pacific staghorn sculpins have large, thin gills that are not modified in response to salinity acclimation, and as a result, these animals show no respiratory compromise during freshwater acclimation, as evidenced by the lack of change in Pcrit, but show significant ion regulatory disturbance. Overall, this study suggests that gill thickening and the resulting respiratory compromise are necessary for freshwater tolerance in sculpins.},
  author       = {Henriksson, Patrik and Mandic, Milica and Richards, Jeffrey G.},
  issn         = {1522-2152},
  language     = {eng},
  number       = {3},
  pages        = {310--319},
  publisher    = {University of Chicago Press},
  series       = {Physiological and Biochemical Zoology},
  title        = {The osmorespiratory compromise in sculpins: Impaired gas exchange is associated with freshwater tolerance},
  url          = {http://dx.doi.org/10.1086/587092},
  volume       = {81},
  year         = {2008},
}