3.1 The significance of using chemical fish toxicants is that more complete population analyses or total eradication, or both, can be accomplished. Target species can be selectively eradicated by varying concentrations. This provides a very effective tool in fisheries investigations and management programs. Water conditions (that is, pH, temperature, alkalinity, and so forth) and morphology can be limiting factors.
3.2 Rotenone—Rotenone used as a fish toxicant is highly versatile and can be used effectively to collect fish samples; to eradicate fish; and to selectively remove certain fish species.
3.2.1 Its effectiveness is reduced in cold <20°C, and dosage required increases with alkalinities. It may also eliminate food web organisms. Fish may be repulsed from treated areas.