A Tale of Tui Chubs

Today Joy, our other wildlife biologist, took me out to Mule Spring at the base of the Inyo Mountains outside of Big Pine and told me a tale of the tui chub there.

The Owens tui chub (Gila bicolor snyderi) is a Federally endangered fish only found in the Owens Basin. It is threatened by habitat degradation, non-native fish, and introgression with the Lahontan tui chub (Gila bicolor obesa), introduced as baitfish. In the early 90s, BLM and DFG biologists wanted to locate sites to establish new populations of Owens tui chub. A granite mining company with Mule Spring on their claim agreed to cooperate, and an artificial pond was created from the spring's outflow. Tui chub were introduced from a pool at Cabin Bar Ranch near Olancha and owned by Budweiser to provide water to their Van Nuys brewery.

The tui chub did well in their new man-made home, and the biologists decided to double down on endangered fish and introduced Owens Valley pupfish as well. On a later visit, the pool was teeming with pupfish, but tui chub were nowhere to be found. The pond was drained and three tui chub were rescued. Apparently the much smaller pupfish (2-3") were so fiesty that they outcompeted the 10-13" tui chubs ! A second pool was created for the pupfish, and the surviving tui chub were allowed to remain in the refilled upper pool. A visit to Cabin Bar Ranch was made to collect more fish to augment the decimated population, but the pools were dry and no fish remained.

As tenacious as the pupfish were, the introduction into Mule Spring turned out to be a good thing. A number of bass were introduced into Fish Slough by well-meaning but uneducated fishermen, and that population of Owens Valley pupfish was virtually eliminated. The bass were removed and pupfish were moved from Mule Spring back into Fish Slough. Talk about managed species !

As if this story wasn't convoluted enough, recent genetic work on the tui chub of Owens Valley determined that the fish of Mule Spring and (formerly) Cabin Bar are actually a genetically distinct subspecies, dubbed toikona tui chub (from the Paiute name for tui chub, ‘‘toikonanishu,’’ which means ‘‘standing in the cat-tails"). Whew ! This is why I prefer birds to fish. Then again, birds can often fly away from adversity, but there's something so desperate about fish only found in rapidly disappearing pools...

tui chub pool reflecting the Inyos

tarantula hawk on Asclepias fascicularis narrow-leaf milkweed

Want excruciating detail on the recent genetic work? Check out:

Chen, Y., S. Parmenter, and B. May. 2007. Introgression between Lahontan and endangered Owens tui chubs, and apparent discovery of a new tui chub in the Owens Valley, California. Conservation Genetics 8:221-238.