Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

Goldfish showed no avoidance of carbofuran up to a concentration of 10 mg/L, but at the onset
of the contaminated flow goldfish showed increased and immediate burst swimming responses
relative to unexposed fish (Saglio, Trijasse et al. 1996). In the same study, olfactometric tests
were performed to assess the influence of 1, 10, and 100 μg/L carbofuran on a suite of behavioral
responses to a food extract (a chironomid–containing solution). Sheltering, grouping, nipping,
burst swimming, and attraction behaviors were assessed for ten minutes at 4, 8, and 12 h time
points. Significant effects to goldfish behavior in the presence of food stimuli were observed as
low as 1 μg/L carbofuran. Sheltering activity increased, while attraction decreased in a dose-
dependent manner at 4 h across treatment range (1-100 μg/L) relative to unexposed fish. At 10
and 100 μg/L, goldfish nipped more, relative to controls; which may be representative of
increased aggression and stress. The authors concluded that olfactory-mediated behaviors in
goldfish were adversely affected by sublethal concentrations of carbofuran. We ranked this
study as relevant to the assessment endpoint of olfaction, as ecologically relevant olfactorymediated
behaviors were tested with sublethal concentrations of carbofuran. We note that
concentrations were not analytically verified and direct correlation of olfactory-affected goldfish
behaviors to salmonid behaviors remains uncertain.
The olfactory ability of male Atlantic salmon to detect a female priming hormone was measured
following 5 d exposures to carbofuran (1.1, 2.7, 6.5, 13.9, 22.7 μg/L ) (Waring and Moore 1997).
The response to the female pheromone prostaglandin F2α, by male olfactory epithelium was
reduced at carbofuran concentrations as low as 1.0 μg/L., while the threshold for detection was
reduced 10-fold. Furthermore, at 2.7 μg/L carbofuran, male fish completely lost priming ability
induced by the female pheromone resulting in no increase in milt or plasma steroids at 2.7 μg/L.
These results suggest that Atlantic salmon exposed to these concentrations would have difficulty
preparing for spawning due to their impaired priming. Reductions in productivity are possible if
male fish miss spawning opportunities. We ranked this study as highly relevant to the effects of
carbofuran on olfactory–mediated behaviors such as spawning synchronization.
Mixtures containing carbaryl, carbofuran, and methomyl
We located no experiments that tested mixtures of the three a.i.s, nor did we find mixture studies
with other N-methyl carbamates. Therefore, the potential for mixture toxicity to olfactory
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