Acute and Sublethal Toxicities of Rotenone in Juvenile Rainbow Trout (Oncorhynchus mykiss): Swimming Performance and Oxygen Consumption

Abstract

Rotenone, a natural insecticide and piscicide, was shown to have an extremely small margin between no lethality (5.0 microg/L) and 100% mortality (6.6 microg/L) for static-renewal 96-hour toxicity tests with juvenile rainbow trout (Oncorhynchus mykiss). Dissolved organic carbon (DOC) at concentrations of 3.0 and 4.0 mg/L significantly increased the rotenone 96-hour LC(50) (median lethal concentration) from 5.80 microg/L (confidence interval (CI) 5.51 to 6.10) to 6.55 microg/L (CI 6.28 to 6.83) and 7.75 microg/L (CI 7.29 to 8.24), respectively, probably as a result of rotenone adsorption onto DOC, which decreased its bioavailability. Using concentrations of 0, 3.0, 4.0, and 5.0 microg/L rotenone and exposure periods of 2, 4, 6, 12, 16, 24, and 48 hours, the threshold concentration of rotenone for impairment of critical swimming performance (Ucrit) was 3.0 microg/L (P = 0.029), with no further impairment at higher concentrations and no time-dependent effect on Ucrit. Using continuous measures of oxygen uptake for 48 hours before and 48 hours during rotenone exposure (0, 1.5, 2.5, 3.0, and 3.5 microg/L), rotenone significantly decreased peak active oxygen uptake at all rotenone concentrations tested without affecting routine oxygen uptake. Fish were individually chased and then placed in rotenone concentrations of 0, 1.0, 3.0, 4.0, 5.0, and 6.0 microg/L to monitor initial postexercise oxygen uptake (Mo2Max) and excess postexercise oxygen consumption (EPOC) during a 40-minute recovery period. Rotenone significantly decreased Mo2Max (P = 0.002) after exposures to 4.0 and 5.0 microg/L, but not 6.0 microg/L, without affecting EPOC.

Physiological Responses of Free-Swimming Adult Coho Salmon to Simulated Predator and Fisheries Encounters

“…In severe cases, delayed mortality is possible (Wood et al 1983). During recovery, metabolic rate may increase to maximum levels (Reidy et al 2000;Cheng and Farrell 2007), supported by increased cardiac output, heart rate (f H ), and cardiac stroke volume. Until routine cardiac output is restored, the circulatory capacity to respond to future encounters is likely compromised.…”

The use of spontaneous behavior, swimming performances and metabolic rate to evaluate toxicity of PFOS on topmouth gudgeon Pseudorasbora parva

“…In contrast to FSP, the Ucrit, which is widely used as an important parameter for the evaluation of the aerobic swimming ability [5,7], was significantly decreased by PFOS exposure (Fig. 3).…”

“…Fast-start swimming is a kind of burst swimming, which is usually used by fish when trying to capture prey or to avoid a predator attack, as well as in any other situation disturbance [2]. By contrast, the Ucrit is the water speed at which a fish can no longer maintain its position or its maximum prolonged swimming speed [7]; it is frequently used to assess the ecological effects of environmental factors on fish in their habitat [4,5,8]. The Ucrit depends largely upon aerobic capacity, whereas the FSP is a kind of anaerobic swimming.…”

Effect of Rainbow Trout Size on Response to Rotenone and Antimycin

“…Gill uptake rate could be affected by some anatomical characteristics, such as the ratio of gill surface area to weight or the distance between gill lamellae (Sijm and Linde 1995;Arnot and Gobas 2006;Cheng and Farrell 2007). For example, the gill surface area : weight ratio varies among strains of rainbow trout (Palzenberger and Pohla 1992), and variation in such characteristics could therefore cause the uptake rate to vary among strains.…”

“…Physiological characteristics that would affect uptake rate are ventilation rate and metabolic rate (Sijm and Linde 1995;Arnot and Gobas 2006;Cheng and Farrell 2007). Variation in the uptake of piscicides was probably not attributable to differences in ventilation rate among fish.…”