Synchronous Mass Spawning In Siphonous Algae A Reproductive Strategy for Efficient Self Propagation

Siphonous seaweeds form an important constituent of the tropical coral reefs. The recent discovery of mass spawning by these seaweeds, comparable to the phenomenon earlier documented for corals, is a landmark contribution to the yet poorly understood coral reef ecology. Exhibiting an extreme sense of timing, a number of species belonging to different genera, inhabiting the tropical sea off the coast of Panama, produce anisogametes on a single day. The gametes are released early in the morning, within a short time span of 5 to 15 min. The extent of spawning is so much that the visibility in the water column is transiently reduced to less than a meter. The gametes are synchronously released at times that are species- and gender-specific. The diel timing of gamete release in distantly related species overlap, while those of the closely related ones are partitioned. However, the time difference is only a few minutes in the total time frame of 5 to 15 minutes. The male gametes of a species are released earlier than the female gametes. Unlike mass spawning behaviour of the corals, the phenomenon in these algae is not influenced by the lunar or tidal cycle. These findings add considerably to the understanding of the reproductive biology of the otherwise poorly understood but important components of coral reefs. The reproductive behaviour unveiled is considered to be a novel strategy for insuring the fertilization success by concentrating the sexual activity temporally and spatially.