Why does egg size of salmonids increase with the mean size of population spawning gravels?
Abstract:Population mean egg size of salmonids increases with the mean size of gravels in which a population spawns. A long-standing hypothesis is that large larvae cannot navigate small-gravel interstices, so mothers must decrease per-offspring investment when spawning gravels are small. We manipulated the size of incubation gravels and egg size of Atlantic salmon (Salmo salar) to test whether size-related entombment of larvae occurs. We find little evidence of size-related entombment, but we find evidence that gravel size does not affect all larval sizes equally. Larger larvae emerge from small gravels before development is complete and with a visible yolk sac, possibly due to oxygen limitation in small gravels. Smaller larvae always complete development in the gravel and emerge without a yolk sac. Although growth and survival may increase with juvenile size following yolk-sac absorption, juveniles with yolk sacs may fare worse when depredation rates are high. The egg size – gravel size correlation may therefore reflect increased postemergence mortality among larger offspring in small-gravel environments. Alternatively, compaction stress in fine gravels coupled with size asymmetries in larval strength may have caused the patterns that we observed, in which case our data may not help explain the egg size – gravel size correlation.
Document Type: Research Article
Publication date: 2011-08-27
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
- Ingenta Connect is not responsible for the content or availability of external websites