|Straus, David - Dave|
Submitted to: North American Journal of Aquaculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/1/2010
Publication Date: 4/8/2011
Publication URL: http://handle.nal.usda.gov/10113/55588
Citation: Ogunsanya, T., Durborow, R.M., Webster, C.D., Tidwell, J.H., Thompson, K., Coyle, S., Jarboe, H.H., Huang, L., Straus, D.L., Wang, C. 2011. Toxicity of rotenone to giant river freshwater prawn Macrobrachium rosenbergii. North American Journal of Aquaculture. 73:159-163. Interpretive Summary: Freshwater shrimp (Macrobrachium rosenbergii) are increasingly being raised in ponds for niche food markets by fish farmers in the United States. When stocking ponds with juvenile freshwater shrimp, any fish present in the ponds will eat the juveniles, so the fish must be eliminated. Rotenone is a compound extracted from the roots and bark of some plants and is extremely toxic to fish, but, no research had been done on the toxicity of rotenone to freshwater shrimp. We designed an experiment to determine this toxicity and found that juveniles should be able to tolerate the concentrations of rotenone required to kill unwanted fish. As an example, the acute toxicity of rotenone to most unwanted fish in culture ponds is about 0.2 ppm; the acute toxicity of rotenone to freshwater shrimp in this study was 6.2 – 7.5 ppm.
Technical Abstract: Aquaculturists have often suffered predation losses in the production of freshwater giant river prawn Macrobrachium rosenbergii due to the presence of wild fish species in culture ponds. The piscicide rotenone is widely used to remove undesirable fish species from ponds. Although evidence in the technical literature suggests that crustaceans generally have a higher tolerance to rotenone than fish, there are currently no data on the acute or chronic toxicity of rotenone to juvenile freshwater prawns. In this study, two static acute-toxicity bioassays (96 h) were conducted using Prentox Prenfish (5% active ingredient) rotenone to determine the median lethal concentration (LC50) for juvenile freshwater prawns (average weight = 0.55 g, SD = 0.25; length = 41.43 mm, SD = 6.45). In bioassay 1, prawns were exposed to rotenone concentrations of 1.0, 3.0, 5.0, and 10.0 mg/L. In bioassay 2, prawns were exposed to rotenone concentrations of 2.2, 3.6, 6.0, 10.0, and 16.7 mg/L. All rotenone concentrations used in the study were based on the total product of the commercial rotenone formulation. The LC50 calculated in bioassay 1 was 6.2 mg/L, and the LC50 calculated in bioassay 2 was 7.5 mg/L. Freshwater prawns were able to tolerate 3.0 to 3.6 mg/L of rotenone with no mortality or apparent adverse effects during the study. Prawns held at the end of each bioassay for 5 d showed no signs of delayed effects from rotenone exposure. Data from this study indicate that juvenile prawns should be able to tolerate the concentrations of rotenone required to eradicate certain problematic wild fish species.