Using native plants to provide natural ecosystem functions in a conservation fish hatchery

The Los Lunas Silvery Minnow Refugium is a conservation fish hatchery that produces the endangered Rio Grande silvery minnow (Hybognathus amarus Girard [Cyprinidae]). The major management goal of a conservation fish hatchery is to raise fish in a naturalized environment that is similar to their native ecosystem, including native vegetation. This is diametrically opposed to management at traditional fish hatcheries, where rooted plants in fish culture units are considered to be weeds because they can cause management problems; most notably, these plants interfere with fish harvest. Fifteen native wetland and 8 native upland species of plants were installed in the naturalized outdoor conservation fish-rearing facility. The plants were used to produce shade, shelter from predators, places for food to colonize, areas of low-velocity water, and to create riparian overbank areas that could be inundated in order to simulate floodplains along the Rio Grande. The plants have thrived at the facility. Continuous manual weeding is required from March to October to remove weeds and to keep sedges and rushes from filling the ponds. Observations indicate that the plants are achieving the intended purposes.