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Theresa L. Martinelli

Publications and source records attributed to Theresa L. Martinelli.

4 recordsLinked to original sources
USGS1998

Growth and physiological responses to surgical and gastric radio transmitter implantation techniques in subyearling chinook salmon ( Oncorhynchus tshawytscha )

We examined the effects of surgical and gastric transmitter implantation techniques on the growth, general physiology and behavior of 230 subyearling chinook salmon (Oncorhynchus tshawytscha, Walbaum) (100 mm-154 mm fork length). The transmitter weighed 1.3 g in air (0.9 g in water) and comprised, on average, 6% of the body weight of the fish (in air). Individuals were randomly assigned to an experimental group (control, surgical or gastric) and a sampling period (day 5 or day 21). Relative growth rate was expressed as% body weight gained/day. General condition was assessed by necropsy. Physiological response variables included hematocrit, leucocrit and plasma protein concentration. The mean relative growth rates of control, surgical and gastric fish were not significantly different at day 5. By day 21, the gastric group had a significantly lower relative growth rate (1.3%) as compared to the surgical group (1.8%) and the control group (1.9%) (P = 0.0001). Mean hematocrit values were significantly lower in the surgical (41.8%) and gastric (42.2%) groups as compared to controls (47.3%) at day 5 (P = 0.01), but all were within normal range for salmonids. No significant differences in hematocrit values were detected at day 21. Leucocrit values for all groups were ??? 1% in 99% of the fish. Both tagged groups had significantly lower mean plasma protein levels as compared to controls at day 5 (P = 0.001) and day 21 (P = 0.0001). At day 21 the gastric group (64.4 g 100 m1-1) had significantly lower mean plasma protein levels than the surgical group (68.8 g 100 ml-1) (P = 0.0001). Necropsies showed decreasing condition of gastrically tagged fish over time, and increasing condition of surgical fish. Paired releases of surgically and gastrically implanted yearling chinook salmon in the lower Columbia River in spring, 1996 revealed few significant differences in migration behavior through two reservoirs. We conclude that gastrically implanted fish show decreased growth and condition over a 21 d period. We recommend a surgical implantation method for long-term studies of juvenile salmonids, however, gastric implantation may be suitable for short-term studies.

Hydrobiologia↗
USGS1997

Seasonal distribution, movements and habitat associations of northern squawfish in two Lower Columbia River reservoirs

We tracked 335 northern squawfish implanted with radio transmitters in the Columbia River in May–December 1993 and May–September 1994. Most fish were released near The Dalles and John Day dams, with the remaining fish released into reservoir areas away from dams. We used boats with mounted Yagi antennas, fixed site receiver stations near the dams and aerial surveys to track movements of tagged northern squawfish. Northern squawfish were commonly associated with water <5 m deep, water velocities <1 m/s and were <45 m from shore. The average movement from the release site was 19.5 km; fish released near dams remained closer to their release sites than fish released into reservoirs. Short‐term movements (successive observations within 24 h) comprised 75% of all detected movements, represented fish moving short distances (mean=0.96 km) between dams and down‐river areas and corresponded to increased passage of juvenile salmonids. Long‐term movements (successive observations exceeding 24 h) were mainly attributed to fish released into the reservoirs moving up‐river to a dam, and fish moving between the two dam tailrace areas. A strong up‐river movement trend terminating at John Day Dam tailrace in June suggested that spawning occurred nearby. Reduced numbers of observations of fish in the autumn suggested that northern squawfish moved away from dam areas and into deeper water for the winter.

Columbia River↗