Diel activity of newly metamorphosed juvenile sea lamprey (Petromyzon marinus)

Abstract

Timing of activity, especially for juvenile anadromous fishes undertaking long migrations can be critical for survival. River-resident larval sea lamprey metamorphose into juveniles and migrate from their larval stream habitats in fall through spring, but diel timing of this migratory behavior is not well understood. Diel activity was determined for newly metamorphosed sea lamprey using day/night net sampling and passive integrated transponder (PIT) telemetry in two natural streams and PIT telemetry in an artificial stream. Downstream migration was primarily nocturnal in all studies. All but one of 372 sea lamprey were captured during night sampling in the day/night net collections and all detections (N = 56) for the in-stream PIT telemetry occurred within a few hours after sunset. Most (81% of 48) tagged lamprey moved downstream during the first night following release and moved at speeds consistent with observed water velocities. During long-term observation of behavior in the artificial stream most sea lamprey movement occurred during the night with limited occurrence of movement during daylight hours. Understanding seasonal and diel timing of downstream migration behavior may allow more effective management of sea lamprey for both conservation and control.

Survival, healing, and swim performance of juvenile migratory sea lamprey (Petromyzon marinus) implanted with a new acoustic microtransmitter designed for small eel-like fishes

“…Understanding consistent individual differences in tag effects on swim performance is likely an important metric to understanding whether and how the effects of the transmitter on swimming will manifest in studies designed to measure movement rates and survival in the wild [73]. Further, out-migrating juvenile lampreys exhibit strong nocturnal patterning in downstream movements, burrowing into sediment or seeking shelter during daylight hours [12,47,54]. In a study with smaller (means of < 120 mm) larval sea lamprey implanted with 8 or 9 mm PIT tags, the tag significantly increased both the time (2.3 × longer) and effort (defined as number of "stops" while burrowing, 1 additional stop on average) necessary for the animal to successfully burrow (vs. untagged fish; [13]).…”

“…PIT tags lack an internal power source, requiring tagged fishes to move within 1-2 m of the antenna to be detected [3,53]. The proportion of PIT-tagged larval and outmigrating lamprey detected by PIT antennas is relatively low, with reported detection rates ranging from 5 to 14% [13,47]. Internally powered telemetry tags (acoustic and radio transmitters) offer an alternative that substantially increases the detection range (tens to hundreds of meters) and detection probability (as high as 80-100% on a well-designed array covering the entirety of the stream channel) at a single receiver [45].…”