Survival and condition of striped bass, steelhead, delta smelt, and wakasagi passed through a Hidrostal pump at the Tracy Fish Collection Facility

Publication Date



bass, BODY, California, collection, collection facility, control, delta smelt, density, descaling, Fins, Fish, fish density, fish facility, fish passage, hidrostal pump, injuries, intake, Morone, morone saxatilis, mortalities, mortality, Oncorhynchus, Oncorhynchus mykiss, operation, passage, pumps, scale, smelt, species, speed, steelhead, striped bass, survival, Tracy, transport

Publication place

Springfield, VA


National Technical Information Service

Series Title

Tracy Fish Facility Studies Vol. 24


A 41 cm diameter Wemco-Hidrostal pump was evaluated for fish passage as part of research to improve salvage operations at the Bureau of Reclamation's Tracy Fish Collection Facility, Tracy, California. Immediate and 96-hour mortality, descaling, and injury rates were evaluated for striped bass, Morone saxatilis, steelhead, Oncorhynchus mykiss, wakasagi, Hypomesus nipponensis, and delta smelt, Hypomesus transpacificus. Test fish inserted into the intake of the Hidrostal pump were compared to control fish that were inserted into the exit. The pump had to significant effect on immediate or 96-h mortality for all species tested, with immediate and 96-h mortality below 3 percent for all trials. Averaged scale loss was below 2.6 percent for all species. Some non-lethal injuries to the head, eyes, skin, and fins of pumped fish occurred; however, these injuries were not significantly different among quality control, control, and treatment fish. No statistically significant relationships were detected between fish motility and pump speed, injected fish density, or debris load. Wakasagi appeared to be more tolerant to pump passage than delta smelt and may not be an appropriate surrogate species for delta smelt. Our results suggest that large Hidrostal pumps have the capacity to transport live fish with low mortality and minimal body injury.

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