Technical Report

Los Lunas Habitat Restoration Fisheries Monitoring

URL: https://webapps.usgs.gov/mrgescp/documents/Hatch%20and%20Gonzales_2008_Los%20Lunas%20Habitat%20Restoration%20Fisheries%20Monitoring.pdf

Date: 2008/10/16

Author(s): Hatch M.D., Gonzales E.

Publication: Report prepared for the U.S. Bureau of Reclamation, 32 p.

Abstract:

The Los Lunas Habitat Restoration Project was designed in part to recouple a portion of the Middle Rio Grande with its floodplain to enhance Rio Grande silvery minnow (silvery minnow; Hybognathus amarus) reproduction and recruitment. The Los Lunas Habitat Restoration Project site is located approximately 5.0 km (3.1 miles) south of Los Lunas along the west bank of the Rio Grande. The Los Lunas Habitat Restoration Project site and the river adjacent to the restoration site are only intermittently inundated.

Results of synoptic fish surveys of river and floodplain habitats and environmental characteristics of these habitats are examined to elucidate how faunal assemblages at this site are structured by underlying physical, chemical, and hydrologic features of the environment. This study documents the occupancy of the Los Lunas Habitat Restoration Project site and the adjacent segment of the main channel by reproductively mature silvery minnow. This information is used to support inferences about silvery minnow reproductive biology and processes such as dispersal and habitat selection.

Occupancy of the floodplain at the Los Lunas Habitat Restoration Project site by reproductively mature silvery minnow was documented over the duration of sampling (May 20 to June 6, 2008). Reproductively mature males and females were most commonly found at sample sites where low velocity flows predominated. A heightened level of floodplain occupation by reproductively mature males and females occurred with a rise in river flow over the period of May 21 to May 23, 2008. Spent females, i.e., females that had obviously spawned, were not observed until calendar week 22 (May 25–May 31).