Hay's Spring Amphipod
Stygobromus hayi

The Hay’s spring amphipod is a tiny shrimp-like crustacean that is only found in Washington, D.C.

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A closeup of a yellowish Hay's spring amphipod showing a rough length of just over five millimeters.
(Photo courtesy of Michelle Brown/Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology)

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Appearance

This tiny, shrimp-like crustacean only grows to a centimeter in length. Since they live underground the Hay’s spring amphipod have no eyes or pigmentation. They are so hard to find that testing water quality samples for traces of the crustaceans DNA is a way to see if they are in a body of water rather than seeing the creature itself.

Feeding

This crustacean feeds on decaying plant and organic matter.

Predators

The Hay’s spring amphipod is extremely sensitive to water quality and water pollution. Increased stormwater runoff and habitat fragmentation are the main threat to this species.

Reproduction and life cycle

Not much is known about the Hay’s spring amphipod life cycle, but based on other stygobromus species it is presumed they hatch from eggs, have a juvenile stage and then become adults that live between four and six years.

Females in the species have a brood pouch and carry their eggs. It is unknown if the reproduction is completely sexual or asexual as well. Some stygobromus go through arthenogenesis which is a form of asexual reproduction.

Did you know?

  • The Hay’s spring amphipod is one of only two federally listed species within Washington, D.C., and is only found within a small range that includes Rock Creek Park and the National Zoological Park.
  • The species was first found in 1938 and declared endangered in 1982.
  • The species is only known to live in 2.5 miles of the Lower Rock Creek Watershed in Washington, D.C. There are seven known populations of the Hay’s Spring amphipod in seepage springs in the area.
  • In 2016 the creature was named Washington, D.C.’s official “state” amphipod to try and raise public awareness about the endangered species

Sources and additional information

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