Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). Atlantic Marsh Fiddler.

摘要

The Atlantic marsh fiddler is the only endemic species of Uca in the Mid-Atlantic region. Males display a series of visual and acoustical displays during mating, with a weak waving and bleaching of the larger claw. Egg clutch size in female varies. Larvae are released in phase with the nocturnal high tides. The 5 zoeal and 1 megalops stages compose much of the estuarine plankton. First and second crab stages are weak and unable to burrow. Adult lifespan is 1 - 1.5 years with 1 - 2 molts per year. Molting is temperature dependent and ceases below 20 C. Crabs feed by scrubbing the preferred muddy substratum for diatoms, fungi, vascular plants, and debris, bioturbating and recycling the marsh surface. This crab is eaten regularly by estuarine birds, fish, crabs, and some mammals. This fiddler can acclimate to lower temperatures, but dies below 2-3 C. or above 40 C. It prefers seawater, lacking freshwater tolerance. Oxygen uptake correlates with activity. Preferred habitats are muddy substrata and short smooth cordgrass. Burrow density decreases from low to high marsh. The Atlantic marsh fiddler has the highest radiation LD-50 of sympatric species of fiddler crabs. Insecticides Temefos, DDT, DDE, Aldrin, and Dieldrin, and contaminant PCB's, mercury, and cadmium reduce populations of fiddlers, some being concentrated in their tissues. Keywords: Uca pugnax, Atlantic marsh fiddler, Endemic species, Salt marsh, Predation, Ecology. (sdw)