Conservation Physiology

28 February 2015 - By: Natalie Sopinka

Efficacy of a sensory deterrent and pipe modifications in decreasing entrainment of juvenile green sturgeon at unscreened water diversions

Sturgeon. Photo: Zeb Hogan

By Natalie Sopinka

Poletto, J.B., Cocherell, D.E., Mussen, T.D., Ercan, A., Bandeh, H., Kavvas, M.L., Cech, J.J. Jr., and Fangue, N.A. (2014). Efficacy of a sensory deterrent and pipe modifications in decreasing entrainment of juvenile green sturgeon (Acipenser medirostris) at unscreened water diversions. Conservation Physiology 2, doi:10.1093/conphys/cou056.

Sturgeon have survived the tests of evolutionary and geologic time, but man-made water diversion pipes may be one their most significant threats to date.  

When unscreened, diversion pipes, which re-direct water from rivers and levees for agriculture, draw in small fishes that may be killed by irrigation pumps or stranded in irrigated channels. Interactions with diversion pipes may be contributing to the “Threatened” status of green sturgeon (Acipenser medirostris) living in California’s Sacramento–San Joaquin watershed. The watershed has over 3000 diversion pipes. Likely due to low burst swimming capacity, 50% of juvenile green sturgeon passing diversion pipes are predicted to be entrained. Modifications to pipe design could reduce entrainment.

Screens on diversion pipes, though an obvious solution, remain inadequate deterrents. Screen installation and maintenance is particularly costly, and fish are still injured when impinged against screens. Graduate student Jamilynn Poletto and colleagues at the University of California at Davis tested how a visual deterrent (a strobe light) and structural changes to diversion pipes (a partially open cap at the end of the pipe or an upturned pipe end) affected entrainment of juvenile green sturgeon. The strobe light was not found to be an effective deterrent;  the proportion of juvenile green sturgeon entrained was similar to that of controls (~60%). The partially-open cap and upturned pipe end did successfully reduce entrainment. Only 4% of migrating juveniles were entrained when the pipe ends were upturned, and 16% were entrained by pipes with partially-open caps.

These structural adjustments did not change water intake, suggesting that mitigating entrainment without compromising agricultural needs is possible in this system. Using a whole animal approach (sensory physiology, ecology, behaviour, life history) when developing strategies to solve conservation problems continues to be an informative strategy. 

Category: Animal Biology
Natalie Sopinka

Natalie Sopinka

Natalie is a postdoctoral research fellow at the Great Lakes Institute for Environmental Research (Windsor, Canada). In collaboration with Yellow Island Aquaculture Ltd., Natalie is studying the interactive effects of maternal stress and rearing enrichment on the performance of Chinook salmon. When she isn’t doing science, Natalie is communicating it; from SEB journal summaries to poems about flatfish. You can find her on Twitter as @phishdoc and at