Reproductive biology and spawning habitat supplementation of the relict darter, Etheostoma chienense, a federally endangered species

We investigated the reproductive biology of Etheostoma chienense in the Bay ou du Chien drainage of western Kentucky. Etheostoma chienense is similar i n its ecology and reproductive biology to other members of the E. squamicep s complex. However, E. chienense is opportunistic in its choice of egg depo sition substrates, as nests were found on a variety of natural and anthropo genic items. Due to an apparent lack of suitable spawning substrates, we ad ded half-cylindrical ceramic tiles to several stretches of stream to increa se potential nest productivity. Egg-clutches attached to artificial substra tes were twice the size of egg clutches attached to naturally occurring mat erials. Laboratory experiments were conducted to determine nest rock size a nd mate choice preferences. Both the size of the male and of the nest rock appeared to be important parameters to spawning females. The life history i nformation gathered here has significant management implications. Artificia l spawning substrates should be placed in appropriate microhabitats (i.e., shallow, low-flow reaches in headwaters). Nest cavity vertical height shoul d be about 3.0 cm and tiles should be spaced at least 0.5 m apart. We feel the use of surrogates (e.g., E. oophlyax) to investigate other ty pes of sp awning cover, and restoration of riparian buffer zones among other actions, would particularly benefit recovery efforts for this endangered species.