Rhinichthys gabrielino

The Santa Ana Speckled Dace has long been recognized as distinct (Swift et al. 1993, Moyle 2002, Oakey et al. 2004) and was formerly described as a full species in 2023 (Moyle et al. 2023). Su et al. (2022) showed that the Santa Ana Speckled Dace is the most distinct genetically of all other dace populations in California, indicating a long history without gene flow from other dace populations. It was previously called Rhinichthys osculus ssp. 8 in this database.

The Santa Aa speckled dace has a very limited range and its populations remain depressed from a variety of anthropogenic threats.

This species was once widespread in the upland areas of three river systems of the Los Angeles Region in southern California: the Los Angeles, San Gabriel, and Santa Ana rivers. The current distribution is restricted to the headwaters of the Santa Ana and San Gabriel rivers and in Big Tujunga Creek (Los Angeles River drainage) (Moyle et al. 1995, Moyle et al. 2015, 2023). Attempts to establish additional populations of Santa Ana speckled dace have been made through introductions into the Santa Clara and Cuyama rivers and into River Springs, Mono County (Moyle et al. 2015)

Based on analysis of Element Occurrences in the California Natural Diversity Database and distribution descriptions in Moyle et al (2015) and Miller (2020), there are likely 4 occurrences of the Santa Ana speckled dace.

Remaining Santa Ana Speckled Dace habitat is in rivers adjacent to heavily populated areas resulting relatively high pollution loads and recreational uses. Historical dams continue to prevent access to suitable habitat for the taxon. Concentrated recreational use continue to have negative impacts on speckled dace in the West, East, and North Forks of the San Gabriel River, Santa Ana River, Lytle Creek, Mill Creek, and Big Tujunga Creek (Miller 2020; Moyle et al. 2015). Recreational uses introduce pollutants and often result in small impoundments used for swimming and fishing that reduce or eliminate down stream flows the impacts of which have been documented in occupied Santa Ana speckled dace streams (Miller 2020). Surface water diversions and impoundments are the primary threat to the Santa Ana speckled dace. Diversions and dams eliminate or modify in-stream flows, degrade former wetland and in-stream habitat quality and availability, and can eliminate access to upstream habitat. Over half of the historical habitat of the Santa Ana speckled dace has been eliminated because of diversions and dams (Miller 2020; Moyle et al 2015). Conversion of lands adjacent to streams occupied by Santa Ana speckled dace to agriculture and urban uses is a serious threat to this taxon. Agricultural operations introduce pesticides and fertilizers into streams that can create toxic conditions fish and aquatic life. Urban uses introduce pollutants from run-off from housing developments and roads resulting in decreased water quality rendering habitat in some areas unsuitable.