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    California Natural Diversity Database (CNDDB) updates to the California roach complex
    • January 12, 2022

    side view of a California roach (fish)
    California roach (Hesperoleucus symmetricus) photographed by © Robin Gwen Agarwal

    Roach are a small (~4 inch), stout bodied minnow in the family Cyprinidae and are distributed throughout much of central California. Various populations of roach have been recognized as California fish Species of Special Concern since the first edition of that project (Moyle et al. 1989) and all naturally occurring populations continue to be recognized as Fish Species of Special Concern (Moyle et al. 2015).

    The taxonomy and nomenclature of roach (and closely related hitch) has been unsettled and complicated over the past 30+ years with various subspecies suggested but not formally described, as well as the genus being lumped or separated with hitch (Hesperoleucus or Lavinia?). Complicating this for CNDDB subscribers is that CNDDB had not updated their species concepts (elements) since about 2010 and they have not aligned with the species profiles presented in the most recent Fish Species of Special Concern (Moyle et al. 2015). The 2015 Fish Species of Special Concern acknowledged that “…a thorough analysis needs to be published in the peer-reviewed literature in order to solidify this taxonomy” (Moyle et al. 2015 page 3 of Central California Roach species account). Subsequent to the 2015 Fish Species of Special Concern, genetic analysis of roach were published in 2017 (Baumsteiger et al. 2017) and in 2019 a formal nomenclature article was published providing names and descriptions supported by the genetic analysis (Baumsteiger & Moyle 2019).

    In reviewing the best available information to update our nomenclature, CNDDB opted to adopt the entity concepts presented by Baumsteiger & Moyle (2019) that builds on and clarifies the previous concepts presented in the 2015 Fish Species of Special Concern. Additionally, CNDDB recognizes that the species accounts in the 2015 report are some of the most detailed accounts for the various roach populations. Generally, across the landscape, the distribution of roach has not changed; what has changed is the names applied to all of those previously known populations. The 2015 Fish Species of Special Concern recognized 3 roach species with 3 named subspecies and 4 undescribed subspecies. This new arrangement recognizes 4 roach species with 4 named subspecies.

    Please reference the enclosed table (PDF) cross walking the roach entity concepts between CNDDB circa 2010, the 2015 Fish Species of Special Concern, Baumsteiger & Moyle 2019, and the updated CNDDB elements as of November 2021. Further, the enclosed figure (PDF) shows the distribution of roach with the different entity concepts over the same time period.

    4 maps that crosswalk the changes in California roach complex over time

    References and resources

    Individual species accounts:

    1. Central California Roach (PDF)
    2. Red Hills Roach (PDF)
    3. Russian River Roach (PDF)
    4. Clear Lake Roach (PDF)
    5. Monterey Roach (PDF)
    6. Navarro Roach (PDF)
    7. Tomales Roach (PDF)
    8. Gualala Roach (PDF)
    9. Northern Roach (PDF)
    Categories: General

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