GUIDING OUT‐MIGRATING JUVENILE SEA LAMPREY (PETROMYZON MARINUS) WITH PULSED DIRECT CURRENT

Abstract

Non‐physical stimuli can deter or guide fish without affecting water flow or navigation and therefore have been investigated to improve fish passage at anthropogenic barriers and to control movement of invasive fish. Upstream fish migration can be blocked or guided without physical structure by electrifying the water, but directional downstream fish guidance with electricity has received little attention. We tested two non‐uniform pulsed direct current electric systems, each having different electrode orientations (vertical versus horizontal), to determine their ability to guide out‐migrating juvenile sea lamprey (Petromyzon marinus) and rainbow trout (Oncorhynchus mykiss). Both systems guided significantly more juvenile sea lamprey to a specific location in our experimental raceway when activated than when deactivated, but guidance efficiency decreased at the highest water velocities tested. At the electric field setting that effectively guided sea lamprey, rainbow trout were guided by the vertical electrode system, but most were blocked by the horizontal electrode system. Additional research should characterize the response of other species to non‐uniform fields of pulsed DC and develop electrode configurations that guide fish over a range of water velocity. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Effects of Electric Barrier on Passage and Physical Condition of Juvenile and Adult Rainbow Trout

“…The effects of electrical current on freshwater fishes have been well studied (Reynolds and Kolz 2012). However, the relationship between fish sizes, barrier configurations, and passage rates through electric barriers has received less attention, and little information exists on the implications of electrical barriers to fish in various life stages (but see Johnson and Miehls 2013;Johnson et al 2014). The deterrence efficiency of an electric barrier is an interaction among multiple factors, including the electrical intensity (voltage gradient) of the field, waveform characteristics, type of barrier configuration (e.g., vertical electrodes [VEs] versus horizontal electrodes), fish size, physiology, and environmental conditions.…”

Electrical Guidance Efficiency of Downstream‐Migrating Juvenile Sea Lampreys Decreases with Increasing Water Velocity

“…Our finding that Sea Lampreys can be guided with pulsed DC at low water velocities is consistent with previous research on electrical guidance of juvenile Sea Lampreys. Johnson and Miehls (2013) found that the electric field increased bypass success by 71% at 10-cm/s water velocity and by 43% at 19 cm/s. We also observed increased bypass success, albeit smaller increases of 8% at 10 cm/s and 12% at 17 cm/s.…”

“…Positive electrodes were spaced at 0.5 m along each line, and negative electrodes were spaced at 0.7 m. The electrode lines were separated by 0.5 m in the upstream array and 0.7 m in the downstream array, producing average voltage gradients of 0.53 V/cm (power density = 30.0 µW/cm 3 ) for the upstream array and 0.42 V/cm (power density = 19.4 µW/cm 3 ) for the downstream array (Figure 2A), as measured at the midpoint between the positive and negative lines every 1 m along the length of each array. The electrode arrays were powered with a NEMO DC pulsator (Procom System S.A., Wroclaw, Poland) that delivered pulsed DC in five-pulse packets; individual pulses lasted 1.8 ms, the interval between pulses within packets was 8.2 ms, and the interval between packets was 250.0 ms (Johnson and Miehls 2013). The goal of the angled installation was to create a vertical electric field of pulsed direct current (VEPDC) in the flume that would guide downstream-moving juveniles from right to left (looking upstream) toward a 1.2-m-wide bypass channel along the left wall at the downstream end of the flume.…”

“…We recently documented that downstream-migrating juvenile Sea Lampreys (hereafter, "juveniles") could be deflected by using pulsed direct current (DC; Johnson and Miehls 2013). In a small laboratory flume (2 m wide × 10-12 cm deep) with a range of low water velocities, significant proportions of downstream-moving juveniles were laterally guided into a 0.5-m-wide section of the flume.…”

“…Second, in the smaller flume, guidance was most effective at 0.78 V/cm (53 µW/cm 3 ), whereas a lower-intensity electric field (0.43 V/cm) increased bypass success by only 7%, which is comparable to the results of the current study. The same pulsator and same pulse settings were used in the Johnson and Miehls (2013) study and in the present experiments; thus, we assume that two factors limited the electric field intensity we were able to achieve. The size of the larger array and the electric field being spread through a larger volume of water may have exceeded the capabilities of our pulsator, and the reinforcing steel within the walls of the large flume may have produced considerable grounding despite our efforts to insulate with plastic sheeting.…”