Freshwater crab Freshwater crab There are around 1,300 species of freshwater crabs, distributed throughout the tropics and subtropics, divided among eight families. They show direct development and maternal care of a small number of offspring, in contrast to marine crabs which release thousands of planktonic larvae. This limits the dispersal abilities of freshwater crabs, so they tend to be endemic to small areas. As a result, a large proportion are threatened with extinction. There are more than 1,300 described species of freshwater crabs, out of a total of 6,700 species of crabs across all environments. The total number of species of freshwater
Arctic National Wildlife Refuge Wildlife Refuge is the only refuge that regularly dens polar bears in that local region, and contains the most consistent amount polar bears in the area. The Arctic basin is the shallowest ocean basin on Earth. It is the least salty, because of low evaporation and large current of freshwater from rivers and glaciers. River mouths and calving glaciers, are continually moving ocean currents contribute to a unique marine ecosystem in the Arctic. The cold, circulating water is rich in minerals, as well as the microscopic organisms (such as phytoplankton and algae) that need them to grow. Marine animals thrive