Technical Report
Rio Grande Silvery Minnow Rescue and Salvage - 2010
Date: 2011/09/07
Author(s): Remshardt W.J., Archdeacon T.P.
Publication: Prepared for U.S. Bureau of Reclamation, 51 p.
Abstract:
Between 28 June and 17 October 2010, 28.2 miles of the main channel of the Middle Rio Grande became intermittent, in the Isleta (8.5) and San Acacia (19.7) reaches. An estimated total of 9,667 Rio Grande silvery minnow were salvaged from isolated pools, transported, and released alive at a location upstream within the same reach as they were salvaged. The take of 95 Rio Grande silvery minnow was attributed to water operations in the Middle Rio Grande during the 2010 irrigation season and assigned as incidental take. This level of observed incidental take was well below the limits established under the determination of incidental take number of 255,390 individuals. The loss of 1,966 Rio Grande silvery minnow was attributed to U.S. Fish and Wildlife Service permit activities. Going into the 2010 salvage season, higher pre-salvage catch rates meant that the allowed Incidental Take number was set higher in 2010 than 2009. This information, along with the fact that we salvaged nearly twice as much in effort (both in river miles and days salvaged) in 2010 compared to 2009 would have suggested that the number of fish observed both alive and dead might have been higher in 2010, but in fact there were nearly half as many RGSM observed in 2010 compared with 2009. Spawning and early recruitment conditions in 2009 were slightly better as a result of higher peak flows and longer duration compared with 2010.