Abstract
Over 56 days of starvation, spiny dogfish Squalus acanthias lost c. 0.3% body mass per day and condition factor and hepato-somatic index declined, but plasma osmolality levels remained higher than seawater levels for the entire period; major osmolytes in the plasma, such as urea, trimethylamine oxide and inorganic ions did not change appreciably. Urea was always the dominant nitrogen waste and was excreted at a constant rate over the 56 day starvation period, suggesting that a minimum rate of urea loss to the environment is unavoidable. Significant amounts of unknown-nitrogen compounds were also excreted at rates higher than that of ammonia. The dogfish can maintain its osmolytes constant despite losing large amounts of nitrogen-rich urea, and therefore maintains plasma hyperosmotic regulation over long-term starvation.
Original language | English (US) |
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Pages (from-to) | 656-670 |
Number of pages | 15 |
Journal | Journal of Fish Biology |
Volume | 72 |
Issue number | 3 |
DOIs | |
State | Published - Feb 2008 |
Externally published | Yes |
Keywords
- Elasmobranch
- Nitrogen excretion
- Osmotic balance
- Starvation
- Urea
ASJC Scopus subject areas
- Aquatic Science