Red-jointed fiddler crabs range into the upper Bay, while marsh and sand fiddler crabs are generally restricted to the middle and lower Bay. Fiddler crabs are small crustaceans with a distinctive enlarged claw. They live on beaches, mud flats and marshes throughout the Chesapeake Bay. Three species of fiddler crabs can be found in the Chesapeake Bay region: the red-jointed fiddler crab, Uca minax , the marsh fiddler crab, Uca pugnax , and the sand fiddler crab, Uca pugilator.
Fiddler crabs vary in color from tan to brown. Sand fiddler crabs are lighter than the other two species. Males have one enlarged claw that can grow to 1. The carapace shell is squared with rounded rear edges. Male marsh fiddler crabs have a royal blue spot on the center of the carapace, while male sand fiddler crabs have a blue or purplish carapace.
Carapace varies in size from less than an inch wide to 1. The marsh fiddler crab is the smallest fiddler crab in the Bay region and the red-jointed fiddler crab is the largest. Fiddler crabs have four pairs of walking legs. Fiddler crabs eat algae, bacteria and decaying marsh plants.
Fiddler crabs Genus Uca , are sexually dimorphic — the males have one large and one small front claw while the females have two small claws.
The males use their small claw for feeding and the large one to attract females for mating, threaten other males and as a weapon when fighting.
Crabs commonly have the ability to regenerate lost limbs after a period of time, and thus declawing is viewed as a potentially more sustainable method of fishing. Common North American species include the marsh fiddler crab Uca pugnax , the china-back fiddler U. These species, which range in body size from about 2. Both claws in the female are relatively small. In males, claws can be regenerated if they are lost. Markus Nolf www. The waving display is also thought to indicate to females the overall healthiness of the male; a more vigorous display is more difficult to do and thus requires the male to be in prime health condition, which suggests that the male will help produce viable offspring.
Male versus male competition also occurs as fighting with the major claws. However, the largest population of these little creatures can be seen in South Carolina. When the juveniles are big enough, they become sexually mature and go on to have their own young. Depending on the type of crab this can take anywhere from several weeks to several months.
Female fiddler crabs that are ready to mate are the ones that choose male crabs to mate with, walking by many claw-waving males before selecting one for mating. Fiddler crabs are one of the most conspicuous inhabitants of the intertidal zone, and they often can be seen foraging in large groups along creek banks when the tide is out.
They thrive in marsh habitats where the substrate is stable enough to allow for the construction of burrows, which can be up to 60 cm 23 in deep. Mud fiddlers range from Massachusetts to Florida and are common along the South Carolina coast. This species has no directly quantifiable commercial value but constitutes an important food source for estuarine animals such as clapper rails, other marsh birds, blue crabs and many other species. As are other estuarine-dependent animals, fiddler crabs are under continuously increasing threat of habitat loss due to land use practices that alter or destroy suitable habitat.
Ruppert, E. Seashore animals of the southeast. Williams, A. Wildlife - Species. Fiddler Crab Uca pugnax Description Fiddler crabs are easily recognized by their square body and marked difference in size between the right and left claws of males.
0コメント