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Swim Speed (swim + speed)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Cholinesterase activity and behavior in chlorpyrifos-exposed Rana sphenocephala tadpoles

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2006
Pamela D. Widder
Abstract Recent studies have found a correlation between organophosphate (OP) pesticide exposure and declines in amphibian populations. We evaluated the hypothesis that this relationship is driven by behavioral changes in developing larvae. Specifically, we examined how exposure to a common OP pesticide, chlorpyrifos, influenced cholinesterase (ChE) activity, mass, and swim speed in Rana sphenocephala tadpoles. We also determined how the presence of natural pond sediments in exposure chambers influenced response to the pesticide and how mass and survival were affected when tadpoles were exposed to an invertebrate (odonate) predator in addition to the pesticide. Mass and swim speed were measured after 4- and 12-d laboratory exposures to 1, 10, 100, and 200 ,g/L of chlorpyrifos in test chambers that either did or did not contain pond sediments. These same parameters also were examined in mesocosms dosed with 200 ,g/L of chlorpyrifos to evaluate responses under more environmentally realistic conditions. The effect of the invertebrate predators on survival and/or growth of tadpoles was evaluated in the mesocosm study and in separate laboratory experiments. In laboratory tests, no pesticide-induced mortality was observed; however, tadpole ChE activity in the two highest concentrations was significantly lowered, with a longer exposure duration further decreasing activity (maximum inhibition, 43%). Mass also was lower at higher concentrations, but this effect was not enhanced with longer duration of exposure. Reductions in ChE activity of tadpoles exposed in mesocosms were similar to those observed in laboratory experiments for the first 4 d. Tadpole swim speed and survival in the presence of a predator were not affected, with the latter largely resulting from pesticide-induced predator mortality. [source]

Relationships between metabolic rate, muscle electromyograms and swim performance of adult chinook salmon

JOURNAL OF FISH BIOLOGY, Issue 4 2003
D. R. Geist
Oxygen consumption rates of adult spring chinook salmon Oncorhynchus tshawytscha increased with swim speed and, depending on temperature and fish mass, ranged from 609 mg O2 h,1 at 30 cm s,1 (c. 0·5 BL s,1) to 3347 mg O2 h,1 at 170 cm s,1 (c. 2·3 BL s,1). Corrected for fish mass, these values ranged from 122 to 670 mg O2 kg,1 h,1, and were similar to other Oncorhynchus species. At all temperatures (8, 12·5 and 17° C), maximum oxygen consumption values levelled off and slightly declined with increasing swim speed >170 cm s,1, and a third-order polynomial regression model fitted the data best. The upper critical swim speed (Ucrit) of fish tested at two laboratories averaged 155 cm s,1 (2·1 BL s,1), but Ucrit of fish tested at the Pacific Northwest National Laboratory were significantly higher (mean 165 cm s,1) than those from fish tested at the Columbia River Research Laboratory (mean 140 cm s,1). Swim trials using fish that had electromyogram (EMG) transmitters implanted in them suggested that at a swim speed of c. 135 cm s,1, red muscle EMG pulse rates slowed and white muscle EMG pulse rates increased. Although there was significant variation between individual fish, this swim speed was c. 80% of the Ucrit for the fish used in the EMG trials (mean Ucrit 168·2 cm s,1). Bioenergetic modelling of the upstream migration of adult chinook salmon should consider incorporating an anaerobic fraction of the energy budget when swim speeds are ,80% of the Ucrit. [source]

Swimming speed and foraging strategies of New Zealand sea lions (Phocarctos hookeri)

JOURNAL OF ZOOLOGY, Issue 2 2001
D. E. Crocker
Abstract Lactating New Zealand sea lions (Phocarctos hookeri) have recently been reported to be the longest and deepest-diving otariid. An unusually large proportion of dives exceeded a theoretical aerobic dive limit, predicted from estimated oxygen stores and measurements of diving metabolic rate. We investigated swimming speed, a key variable in both the management of oxygen stores and foraging strategies, and its relation to diving behaviour in New Zealand sea lions. Diving behaviour was nearly continuous with short inter-dive intervals. Mean diving swimming speeds ranged from 1.6 to 2.4 m/s. Mean surface swimming speeds ranged from 0.9 to 1.8 m/s and were significantly lower than diving speeds in all subjects. New Zealand sea lions spend significant but variable amounts of time resting at the surface. Diving and swimming speed patterns were consistent with foraging on the benthos. Time in the foraging zone was maintained in deeper dives by increasing dive duration. This increased duration cannot be accounted for by a decreased metabolic rate resulting from slower swimming speeds, as speeds increased with the maximum depth of dives. Patterns of swimming speed and acceleration suggest the use of a gliding phase during descent. For most females, the extended duration of deeper dives did not impact on surface times, suggesting the use of aerobic metabolism. Females exhibited significantly slower swim speeds during the bottom segments of foraging dives than during descent or ascent. These findings suggest that swimming behaviour should be considered a critical component when modelling energetic costs for diving animals. [source]