Rectal gland morphology of freshwater and seawater acclimated bull sharks Carcharhinus leucas

Pillans, R. D., Good, J. P., Anderson, W. G., Hazon, N. and Franklin, C. E. (2008) Rectal gland morphology of freshwater and seawater acclimated bull sharks Carcharhinus leucas. Journal of Fish Biology, 72 7: 1559-1571. doi:10.1111/j.1095-8649.2008.01765.x


Author Pillans, R. D.
Good, J. P.
Anderson, W. G.
Hazon, N.
Franklin, C. E.
Title Rectal gland morphology of freshwater and seawater acclimated bull sharks Carcharhinus leucas
Formatted title
Rectal gland morphology of freshwater and seawater acclimated bull sharks Carcharhinus leucas
Journal name Journal of Fish Biology   Check publisher's open access policy
ISSN 0022-1112
1095-8649
Publication date 2008-05-01
Year available 2008
Sub-type Article (original research)
DOI 10.1111/j.1095-8649.2008.01765.x
Volume 72
Issue 7
Start page 1559
End page 1571
Total pages 13
Place of publication London
Publisher Blackwell
Language eng
Subject C1
970106 Expanding Knowledge in the Biological Sciences
0606 Physiology
0608 Zoology
0704 Fisheries Sciences
Abstract To compare rectal gland morphology of bull sharks Carcharhinus leucas, animals captured in the freshwater reaches of the Brisbane River, Australia, were acclimated to sea water over 17 days with 1 week in the final salinity. A control group was left in fresh water for 17 days. Animals in fresh water and sea water were strongly hyper- and hypo-ionic with respect to plasma Na+ and Cl–, respectively. This difference necessitates NaCl secretion by the rectal gland in sea water and conservation of NaCl in fresh water. Structural differences in the rectal gland of freshwater and seawater acclimated bull sharks were limited. There was no difference in rectal gland cross-sectional area, lumen area, rectal gland vein area, number of secretory tubules or secretory cells per secretory tubule in freshwater and seawater acclimated animals. At a cellular level, there was no difference between the degree of basolateral and lateral folding, number of mitochondria or number of desmosomes per tight junction. Tight junction width was significantly greater in seawater acclimated animals. The number of red blood cells in the interstitial tissue was also significantly higher in seawater acclimated animals, possibly as a result of increased blood perfusion of the secretory epithelia. The lack of major structural changes in the rectal glands of bull sharks acclimated to fresh water and sea water most likely represents the salinity gradient in the Brisbane River where animals are found throughout the river and can experience large fluctuations in salinity over short distances. Differences in rectal gland morphology of bull sharks in fresh water and sea water are discussed in terms of their relevance to osmoregulation in elasmobranchs.
Keyword elasmobranchs
euryhaline
morphology
osmoregulation
rectal gland
Q-Index Code C1
Q-Index Status Confirmed Code
Additional Notes doi:10.1111/j.1095-8649.2008.01765.x, available online at http://www.blackwell-synergy.com

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
School of Biological Sciences Publications
Ecology Centre Publications
 
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Created: Thu, 05 Jun 2008, 21:11:50 EST by Thelma Whitbourne on behalf of School of Biological Sciences