Publication

Rio Grande Silvery Minnow Augmentation in the Middle Rio Grande, New Mexico Annual Report 2021

URL: https://webapps.usgs.gov/mrgescp/documents/Archdeacon_2022_RGSM-Augmentation-in-the-MRG-2021-Annual-Report.pdf

Date: 2022/03/08

Author(s): Archdeacon T.P.

Publication: Prepared by U.S. Fish and Wildlife Service, New Mexico Fish and Wildlife Conservation Office. Prepared for U.S. Bureau of Reclamation, 28 p. DOI:10.13140/RG.2.2.11148.59520.

Abstract:

• This report covers New Mexico Fish and Wildlife Conservation Office (NMFWCO) Rio Grande Silvery Minnow (RGSM) augmentation activities for the 2021 cohort.
• Spring runoff in early 2021 was moderately low, resulting in a request of 240,000 hatchery-reared age-0 fish to supplement the wild 2021 cohort and an additional 12,000 for a movement study.
• The colors of visible implant elastomer (VIE) tags used for identifying RGSM released in 2021 were yellow right dorsal for the Albuquerque BioPark Aquatic Conservation Facility (BioPark), red right dorsal for the Southwestern Native Aquatic Resources and Recovery Center (Southwestern ARRC), and green right dorsal for the Los Lunas Silvery Minnow Refugium (LLSMR). Additionally, RGSM tagged with passive integrated transponders (PIT) for a fish movement study were tagged with blue VIE on the right dorsal. Fish were tagged to the extent possible within constraints during the COVID-19 pandemic.
• Based on September 2021 population monitoring, the Middle Rio Grande valley had less than 1.0 RGSM per 100m2 and greater than 50% occupied sites in the Angostura and Isleta reaches, leading to a final request of 124,000 RGSM. The San Acacia reach required no augmentation based on September 2021 monitoring; however, subsequent drying occurred and 41,000 additional RGSM were requested for release in the San Acacia reach in anticipation of the effects of drying on the wild population.
• Approximately 194,511 hatchery-reared age-0 Rio Grande Silvery Minnows were released in November and December 2021. Of these, 94,222 were given a VIE tag prior to release.
• 4,873 PIT tagged fish were released in March and another 9,338 were released in December 2021 in support of a fish movement study.
• 337 VIE-marked fish were recaptured between January and December 2021, with 1 from the 2019 cohort, 272 from the 2020 cohort, 53 from the 2021 cohort, and 11 PIT-tagged RGSM. The majority of recaptures (N = 271) were during fish rescue activities, including the single fish from the 2019 cohort.