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Mckenzie, David; Blasco, Felipe R.; Belao, Thiago C.; Killen, Shaun S.; Martins, Nathan D.; Taylor, Edwin W.; Tadeu Rantin, F.. |
Individual variation in sub-lethal sensitivity to the organophosphate pesticide trichlorfon was investigated in Nile tilapia, using critical swimming speed (U-crit) as an indicator. Tilapia exposed for 96 h to 500 mu g l-1 trichlorfon at 26 degrees C (Tcfn group, n = 27) showed a significant decline in mean U-crit, compared to their own control (pre-exposure) performance in clean water (-14.5 +/- 2.3%, mean +/- SEM), but also compared to a Sham group (n = 10) maintained for 96 h in clean water. Individuals varied in their relative sensitivity to the pesticide, with the decline in U-crit after exposure varying from 1 to 41%. The U-crit of the Tcfn group did not recover completely after 96 h in clean water, remaining 9.4 +/- 3.2% below their own control... |
Tipo: Text |
Palavras-chave: Trichlorfon; Critical swimming speed; Metabolic rate; Respirometry; Nile tilapia; Individual variation. |
Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00625/73705/74889.pdf |
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Mckenzie, David; Belao, Thiago C.; Killen, Shaun S.; Rantin, F. Tadeu. |
The African sharptooth catfish Clarias gariepinus has bimodal respiration, it has a suprabranchial air-breathing organ alongside substantial gills. We used automated bimodal respirometry to reveal that undisturbed juvenile catfish (N=29) breathed air continuously in normoxia, with a marked diurnal cycle. Air breathing and routine metabolic rate (RMR) increased in darkness when, in the wild, this nocturnal predator forages. Aquatic hypoxia (20% air saturation) greatly increased overall reliance on air breathing. We investigated whether two measures of risk taking to breathe air, namely absolute rates of aerial O-2 uptake ((M) over dotO(2), air) and the percentage of RMR obtained from air (% (M) over dotO(2), air), were influenced by individual standard... |
Tipo: Text |
Palavras-chave: Bimodal respiration; Energy metabolism; Hypoxia; Personality; Respiratory partitioning; Risk-taking. |
Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00626/73822/73663.pdf |
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