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Thesis
Salinity Effect on Urea and Tmao Levels in Blood Plasma of Atlantic Stingray, Dasyatis Sabina
University of West Florida Libraries
Master of Science (MS), University of West Florida
2007
Abstract
The range of osmolyte adjustment tolerated by euryhaline species such as the Atlantic stingray has never been quantified. The purpose of my experiments was to determine how salinity affects osmolytes involved in osmoregulation of Atlantic stingray. Plasma osmolality and TMAO and urea concentrations were measured for 50 Atlantic stingrays acclimated at five salinity treatments between 5 and 60‰. Although Atlantic stingrays in my experiments stopped eating above 50‰, fish showed the typical hyperosmotic pattern at salinities up to 60‰. Osmolality remained constant (721 mOsm) at salinities below 20‰ but increased more slowly than ambient salinity above 20‰. Urea concentrations in my study were consistent with reports for Atlantic stingray and other elasmobranchs. Euryhaline elasmobranch species seem to exhibit a greater capacity for urea retention. Concentrations of TMAO were nearly 45% lower than levels in other elasmobranchs. Although other osmolytes are shown to be important in some elasmobranchs, it is unclear what role they may play for Atlantic stingray. Steady increases in TMAO levels even after fish stopped eating, indicate that TMAO levels are likely controlled by physiology and not diet. Low TMAO values in spite of high urea and osmolality leave open the question of how Atlantic stingrays fill the osmotic deficit.
Details
- Title
- Salinity Effect on Urea and Tmao Levels in Blood Plasma of Atlantic Stingray, Dasyatis Sabina
- Resource Type
- Thesis
- Publisher
- University of West Florida Libraries
- Format
- pdf
- Number of pages
- 41
- Copyright
- Permission granted to the University of West Florida Libraries to digitize and/or display this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires the permission of the copyright holder.
- Identifiers
- 99380090719006600
- Academic Unit
- Biology
- Language
- English
- Awarding Institution
- University of West Florida; Master of Science (MS)
- Theses and Dissertations
- Master of Science (MS), University of West Florida