Pacific lampreys (Lampetra tridentata) have declined in abundance in the
Columbia River Basin. Although, the reasons for the decline are unclear, we suggest that
development of hydroelectric dams and habitat alterations in tributaries as the main
causes. The available knowledge of life history of Pacific lampreys and status from dam
counts (trend data) in the Columbia River Basin and the Umpqua River along the Oregon
Coast shows that populations have been declining over the last 30 years. Even though
Pacific lampreys have been shown to have ecological importance both as predator and
prey, the declines in their populations have been largely ignored by fisheries agencies and
the public.
Recently, the National Marine Fisheries Service initiated studies on using radio-telemetry
of Pacific lampreys in order to study the impact of hydroelectric dams on
migration behavior. To address one of the fundamental assumptions of radio-telemetry,
namely, that tagged fish are "normal," one must be able to measure whether or not an
animal is stressed. We identified clinical indicators of stress in adult Pacific lampreys.
Plasma glucose became elevated soon after acute stress and remained elevated for one
week. Plasma lactate also became elevated by 30 minutes; however, it decreased to
resting levels by one hour after stessor. Muscle lactate was shown to have an inverse
relationship with glucose. Muscle lactate levels decreased by 4 hours and remained
depressed for two days. Plasma chloride ions decreased by one hour, then returned to
resting levels by 8 hours; by 24 hours, levels were again decreased with recovery
occurring by 48 hours. The steroid cortisol was not found in the plasma of Pacific
lampreys.
The swimming performance and physiological effects of surgical implantation of
three different sized dummy radio transmitters in Pacific lampreys were assessed.
Intraperitoneal implantations of 3.4 g transmitters had no significant effect on circulating
levels of glucose (an indicator of stress) 4 months after surgery, while 10 gram
transmitters showed a significant increase in plasma glucose. Lampreys implanted with
7.4 g transmitters recovered from surgery by day 4 based on levels of plasma glucose.
Lampreys implanted intraperitoneally with 7.4 g dummy transmitters showed no
significant differences in circulating glucose 30, 60, 90, and 180 days after surgery in
comparison to sham-implant controls. Ventilation rate decreased significantly by 30
minutes after surgery and was stable by 60 minutes; suggesting initial recovery from
surgery is rapid. Swimming performance was impaired immediately after surgery;
however, swimming was not compromised at 1 and 7 days after surgery.
Tagged fish showed a significant difference in oxygen consumption when tested
immediately after surgery; however, oxygen consumption was at control levels at 1 and 7
days after surgery. / Graduation date: 2001
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32781 |
| Date | 19 January 2001 |
| Creators | Close, David A. |
| Contributors | Fitzpatrick, Martin S., Li, Hiram W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
Page generated in 0.002 seconds