Hesperoleucus venustus

Based on morphological (Brown et al. 1992) and genetic analyses (Aguilar and Jones 2009; Baumsteiger et al. 2017), the Central Valley and coastal populations of Hesperoleucus symmetricus are recognized as distinct species. Hesperoleucus venustus applies to the populations in the coastal drainages and H. symmetricus to populations in the Central Valley drainages (Baumsteiger and Moyle 2019).

While there is still uncertainty about recognizing Lavinia and Hesperoleucus as distinct genera (e.g., Aguilar and Jones 2009, Schönhuth et al. 2012), genomic analyses by Baumsteiger et al. (2017) supported recognition of distinct lineages, despite occasional hybridization between them.

This species is restricted to coastal watersheds, largely west of the coastal mountain range in California, USA. The northernmost native population is in the Navarro River. Excluding the Gualala River, watersheds south of the Navarro River do not support any Roach populations until the Russian River. Populations are then found intermittently from the Russian River south to the Tomales Bay region. Scattered Coastal Roach are found in streams around San Francisco Bay absent from coastal watersheds to the south until the Salinas and Pajaro river watersheds of the Monterey region. The population in Soquel Creek (Santa Cruz Co.) is probably introduced from the Salinas River, while the origin of the population in the Cuyuma River (San Luis Obispo and Santa Barbara counties) is uncertain but may be native (Moyle 2002, Baumsteiger et al. 2019).

It is widespread in the Eel River, from an introduction in the early 1970s. This introduction was noted by Moyle (2002), confirmed by Baumsteiger et al. (2017). Studies show that Eel River fish originated from the Russian River mainstem and not the recently connected East Fork (Baumsteiger et al. 2019).