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NEW DESIGN FOR AIRLIFT PUMP USED IN FISH CULTURE TANKS WITH THE ENDANGERED RIO GRANDE SILVERY MINNOW (Hybognathus amarus)
Douglas Tave
; Los Lunas Silvery Minnow Refugium, New Mexico Interstate Stream Commission, 1000 Main St. NW, Building H, Los Lunas, NM 87031 USA
Lawrence Valenzuela
; 2439 Trujillo St., Los Lunas, NM 87031 USA
Louie Toya
; Los Lunas Silvery Minnow Refugium, New Mexico Interstate Stream Commission, 1000 Main St. NW, Building H, Los Lunas, NM 87031 USA
Alison M. Hutson
; Los Lunas Silvery Minnow Refugium, New Mexico Interstate Stream Commission, 1000 Main St. NW, Building H, Los Lunas, NM 87031 USA
Sažetak
This article describes an airlift pump used to produce a circular flow in a fish culture tank that does not attach to the tank. The design produces an airlift pump that does not swing back and forth or float upwards while in use. It is easy to build, inexpensive, and can be quickly installed and removed so that it does not interfere with sampling or harvest. The airlift pump was evaluated during a 30-d survival trial with the endangered Rio Grande silvery minnow (Hybognathus amarus) in 2.44-m-diameter circular tanks (3,666 l). Because the fish is endangered, all new culture units must be evaluated in a survival trial. To be able to use a new 15-tank system, survival had to be evaluated in a random representation of three tanks. U.S. Fish and Wildlife Service, which regulates all activities with this endangered species, decided that permitted take (maximum permitted mortality) was 60% for the survival trial; consequently, survival >40% in each tank would be considered successful. Two airlift pumps were placed in each tank. The two airlift pumps moved a mean±SD of 33.697±5.563 l/min; this produced total tank turnovers through the airlift pumps of 110.65±16.93 min. Water velocities were measured at nine locations in the tanks. Water velocities were 0.0-0.04 m/sec. Dissolved oxygen concentration never went below 6.30 mg/l. The airlift pumps operated flawlessly and required no maintenance. They produced water velocities preferred by the fish and helped keep dissolved oxygen concentration above the permitted minimum (5 mg/l). The airlift pumps will be used in future fish culture activities in these and other tanks. Survival in the three tanks was 78%, 94% and 96%; overall survival was 89.3%. Because take (10.7%) was under the permitted level (60%), the trial was successful.
Ključne riječi
Airlift pump; Rio Grande silvery minnow; Hybognathus amarus
Hrčak ID:
93505
URI
Datum izdavanja:
3.10.2012.
Posjeta: 3.359 *