If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

Oxygen as a constraining factor in egg size evolution in salmonids

$50.00 plus tax (Refund Policy)

Buy Article:

Abstract:

Differential survival at low oxygen levels has been proposed as a mechanism for maintaining high within-population variability in egg size in fish. Whether low oxygen levels favour large or small eggs, however, is not clear. To address this question, the effects of egg size on metabolic rates, critical dissolved oxygen levels (Pc), and P50 oxygen levels of Chinook salmon (Oncorhynchus tshawytscha) embryos and alevins were determined. Embryonic metabolic rate expanded at a slower rate with increasing egg mass (allometric constant (b) = 0.30) than did capsule surface area (b = 0.67), indicating that larger eggs have larger surface areas relative to their metabolic demand for oxygen. A relatively larger area, however, did not translate into significant differences in Pc or P50 values at the egg stage. After hatch, metabolic rate expanded at a rate proportional to (egg mass)0.62. Pc levels were significantly higher for alevins from larger eggs for the first but not second half of the alevin stage. Egg size had no significant effect on P50 values at any time during the alevin stage. The modest impact of egg size on hypoxic tolerance of developing Chinook suggests that factors other than oxygen are involved in maintaining high within-population variability in egg size.

On a proposé la survie différentielle aux faibles concentrations d'oxygène comme mécanisme explicatif du maintien dans la population d'une forte variabilité de la taille des oeufs chez les poissons. Il n'est pas clair, cependant, si les concentrations basses d'oxygène favorisent les gros ou les petits oeufs. Pour répondre à cette question, les effets de la taille des oeufs sur le taux métabolique, les concentrations critiques d'oxygène dissous (Pc) et les concentrations P50 ont été déterminés chez des embryons et des alevins du saumon chinook (Oncorhynchus tshawytscha). Le taux métabolique des embryons croît à un rythme plus lent en fonction de la masse des oeufs (constante d'allométrie, b = 0,30) que la surface de la capsule ( b = 0,67), ce qui indique que les oeufs plus gros ont des surfaces plus grandes relativement à leur demande métabolique en oxygène. Cependant, la surface relativement plus grande ne se reflète pas dans des valeurs de Pc ou de P50 significativement différentes au stade de l'oeuf. Après l'éclosion, le taux métabolique croît à un rythme proportionnel à la (masse de l'oeuf)0,62. Les valeurs de Pc sont significativement plus élevées pour les alevins provenant de gros oeufs durant la première, mais non la seconde, partie du stade de l'alevin. La taille de l'oeuf n'a aucun effet significatif sur les valeurs de P50 en aucun moment du stade de l'alevin. Le faible impact de la taille de l'oeuf sur la tolérance à l'hypoxie chez les saumons chinook en développement laisse croire que ce sont des facteurs autres que l'oxygène qui sont impliqués dans le maintien de l'importante variation de taille des oeufs dans les populations.[Traduit par la Rédaction]

Document Type: Research Article

Publication date: April 1, 2007

More about this publication?
  • Published continuously since 1901 (under various titles), this monthly journal is the primary publishing vehicle for the multidisciplinary field of aquatic sciences. It publishes perspectives (syntheses, critiques, and re-evaluations), discussions (comments and replies), articles, and rapid communications, relating to current research on cells, organisms, populations, ecosystems, or processes that affect aquatic systems. The journal seeks to amplify, modify, question, or redirect accumulated knowledge in the field of fisheries and aquatic science. Occasional supplements are dedicated to single topics or to proceedings of international symposia.
  • Information for Authors
  • Submit a Paper
  • Subscribe to this Title
  • Terms & Conditions
  • Sample Issue
  • Reprints & Permissions
  • ingentaconnect is not responsible for the content or availability of external websites
Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more