Technical Report

Progress Report - 2003 Contributions to Delisting Rio Grande Silvery Minnow: Egg Habitat Identification

URL: https://webapps.usgs.gov/mrgescp/documents/Reclamation_2003_Contributions%20to%20Delisting%20RGSM%20Egg%20Habitat%20Identification.pdf

Date: 2003/09/01

Author(s): Porter M.D., Massong T.M.

Publication: U.S. Bureau of Reclamation Report, 12 p.

Abstract:

The Rio Grande silvery minnow (Hybognathus amarus) (silvery minnow) was listed as an endangered species in 1994 (U.S. Department of the Interior 1994). The declining silvery minnow population in the Rio Grande and Pecos River is thought to be due to loss of habitat following dam construction (Bestgen and Platania 1991). The current Biological Opinion (U.S. Fish and Wildlife Service, 2003) and the Middle Rio Grande Collaborative Program recognize the importance of habitat restoration in achieving, stabilizing, and recovery of the species. Knowledge of how geomorphology and hydrology affect egg retention will improve our ability to design and construct useful habitat restoration projects. The project goal is to identify simple, effective habitat features that can be applied economically at numerous sites. Fiscal year 2003 goals included: 1) using artificial eggs to examine existing channel features where egg retention is believed to occur, and 2) determine the effectiveness of creating silvery minnow egg retention habitat (nursery habitat) at two ongoing habitat restoration projects.

In fiscal year 2003, potential nursery habitats at one existing channel (North AMAFCA Channel) and two habitat restoration locations (Los Lunas and Bosque Del Apache) were sampled (Figure 1). The Los Lunas site is a habitat restoration project funded under the ESA Collaborative Program. The Bosque del Apache (BDA) site is a habitat restoration project built as mitigation for river maintenance activities in the headwaters of Elephant Butte Reservoir. The two habitat restoration sites were visited in mid-May 2003 when the silvery minnows were spawning. The third site, North AMAFCA Channel (AMAFCA), is the north storm diversion channel for the City of Albuquerque located on Sandia Pueblo. The outfall area within 100 m of the mouth was visited in July 2003, outside the normal spawning period for silvery minnows.