Mud Fiddler Crab (Uca Pugnax)

Mud Fiddler Crab is found in the Brachyura infraorder, the most advanced of decapods (10 legged crustaceans) (Wenner, 1). Fiddler Crabs are easily recognizable for their large claw that only the males of their species possess. This large claw changes from 2% to 65% of their body weight as they grow from larvae to a mature adult (Wenner, 1). There is a 50/50% chance that either claw will be their notorious large claw (Wenner, 1). Mud Fiddler crabs can be found from Marshes to deep within the Subtidal Soft Bottom. Mud Fiddler Crab is easily distinguishable from other Fiddler Crabs by their long and thin eyestalks (usually blue) and an H-like depression in their carapace (Wenner, 2).

Geological Oceanography: Mud Fiddler Crabs are known for their extensive burrowing (Wenner, 1). This extensive burrowing is a common cause for the erosion of coast lines and marshes along the Eastern Seaboard (Wenner, 1). Fiddler Crabs are found extensively from Cape Cod in Massachusetts to the Florida Keys (Wenner, 1). Sediment of the Subtidal Soft Bottom is the perfect environment for them to thrive in because it’s muddy and has a lot of sediment for burrowing.

Chemical Oceanography: Fiddler Crabs are known to feed off of organic material extracted from mud (Wenner, 2). This makes the Fiddler Crab extremely sensitive to pesticides from runoff, because many pesticides sink to the bottom of Subtidal Soft Bottom floor, making them highly susceptible to consumption by them (Wenner, 2). This problem is very common within Sounds and Estuaries, the common location of the Subtidal Soft Bottom (Wenner, 2) Much like Oil sinking to the bottom of the Gulf following the Deep Water Horizon spill, pesticides can sink to the Sub-tidal Soft Bottom, contaminating the mud and silt that Mud Fiddler Crabs live in.

Physical Oceanography: Once again, Mud Fiddler Crabs LOVE to burrow! This has strongly influenced the erosion in the Mississippi River Delta and Chesapeake Bay.

All information including the picture is obtained from the following source:

Wenner, Elizabeth. "Fiddler Crabs." Http://www.dnr.sc.gov/. South Carolina Department of Natural Resources. Web. 5 May 2011. .