Disponibilité du sperme au cours de la saison de la ponte de l'oursin vert, Strongylocentrotus droebachiensis, dans des populations de différentes tailles
|Advisor:||Himmelman, John; Wahle, Richard A.|
|Abstract:||Recent experimental studies with gamete-spawning organisms indicate sperm availability and in turn fertilization success may be sensitive to changes in population abundance. However, the occurrence of sperm limitation is controversial and few studies have measured fertilization rates during natural spawnings. During 2002 and 2003, we used fertilization assays to quantify sperm availability near urchin populations of different abundances. Extensive spawning and fertilization rates near 100% were observed near a large population, whereas smaller populations showed lower and less sustained fertilization rates and no drop in gonad size. Some increases in sperm availability occurred at the same time in different populations, suggesting spawning in response to a large-scale cue. We speculate that mass, synchronous spawning is more likely in large populations where gametes or pheromones from conspecifics reach concentrations that are high enough to trigger spawning in less responsive urchins.|
|Document Type:||Mémoire de maîtrise|
|Open Access Date:||11 April 2018|
|Collection:||Thèses et mémoires|
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