A Suite of Adaptations for Intertidal Spawning1

• Main Author: Malcolm H. Taylor
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Tive; Vae; Newfoundland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.632.254; http://icb.oxfordjournals.org/content/39/2/313.full.pdf

SYNOPSIS. Salt marshes and similar tide-dominated habitats present an unusual challenge for reproduction of resident aquatic organisms. Strong currents, siltation and hypoxia can potentially contribute to reproductive failure through mortality of the eggs or flushing of the eggs and larvae from the habitat. Fundulus hetero-clitus, a small brackish water killifish, is a common resident of tidal marshes along the east coast of North America from Newfoundland to Florida. The reproductive strategy of this and related species is based on aerial incubation of eggs in the high intertidal zone. The eggs are resistant to desiccation and, when fully developed, hatch on immersion. Copulatory behavior and anatomy of accessory reproductive structures are adapted to placement of eggs in protected incubation sites. The gonads of both males and females mature rhythmically with an endogenous cir-casemilunar period, which is synchronized with the "spring " tides of new and full moons. Spawning occurs on high tides. Embryos develop in 9—15 days, and usually hatch on the succeeding spring tide series. Reproductive cyclicity in F. heteroclitus and related fishes ensures that spawning fish will have access to the high intertidal zone, thereby permitting aerial incubation of eggs. High intertidal spawning in fishes in-volves a complex reproductive strategy re-quiring adaptations in adults, eggs and lar-vae. The adults typically display reproduc-tive cyclicity that ensures sexual maturity at the times of most complete immersion of the intertidal zone, when spawning sites are accessible. In addition, eggs of intertidal spawners are adapted to resist desiccation and hatch only when immersed in water. Larval development is completed and the embryos are ready to hatch before a suc-ceeding spring tide series inundates the spawning sites. The fry are immediately free-swimming and able to survive in tide-marsh and shore-zone environments. Many high intertidal spawners belong to the order Atheriniformes. The California