In which situation might coral species not spawn in large numbers?

For brooding species, coral polyps reproduce through a method that does not rely on mass spawning events. Unlike broadcast spawning species, which release eggs and sperm into the water for external fertilization, brooding species internally fertilize their eggs and typically release fully developed larvae instead of gametes. This strategy is adapted to their environments, allowing them to ensure offspring survival in a more controlled manner and avoid the risks associated with large-scale spawning, such as predation or unfavorable environmental conditions. Therefore, brooding species would not produce large numbers of gametes at any one time, distinguishing their reproductive behavior from that of mass spawning corals.

In contrast, the other options generally relate to conditions that might promote spawning in broadcast spawning coral species. Stable temperatures, nutrient levels, and high light conditions could enhance the spawning process in those species, leading to larger spawn events.