Science Cafe: What Lives in Potholes and How?

 Presented by Randy Van Haverbeke, USFWS Senior Fish Biologist

Scattered atop the sandstone formations of northern Arizona and Utah are small windblown depressions called rock pools. They range in size from small teacups to massive cylindrical pits with vertical walls. Bathtub size is common, and there are thousands surrounding the Lake Powell region. Most pools dry periodically, but fill with water during the summer monsoon seasons. Inside these remote habitats live fascinating but seldom seen animal communities. Each rock pool is nearly a world unto its own. Among the most interesting members of these communities are the Branchiopods (the “gilled feet” animals). These small shrimp-like animals have evolved for life in ephemeral aquatic habitats, their eggs capable of withstanding desiccation and freezing for unknown periods of time, perhaps decades or longer. Among the gilled feet community members are graceful swimming filter feeders (fairy shrimp), bumbling but protected clam shrimps, and predacious cannibalistic miniature monsters called tadpole shrimp. Each species is uniquely adapted for survival in their often unforgiving and harsh environments.

Randy works on collaborative fish monitoring efforts in Grand Canyon with other Federal, State, Tribal, and private partners. Specifically, he is responsible for stock assessment activities on humpback chub (Gila cypha), including study design, data collection, data analyses, interpretation of results, and writing interim and final reports. In addition, Randy has worked extensively on native fish issues in the lower Colorado, Verde, and Salt river ecosystems. Randy’s areas of expertise include: limnology, fisheries management, stock assessment, genetics, statistics, chemistry, and technical writing and editing. Randy_Vanhaverbeke@fws.gov