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Piscicides, Toxicants, and Explosives

Piscicides, Toxicants, and Explosives. Reasons for using toxicants:. Control undesirable fish in favor of sport species; e.g. suckers or carp Eradicate exotic species; e.g., snakehead Eradicate competitors Control fish diseases Restoration of endangered species. Toxicants for fish sampling

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Piscicides, Toxicants, and Explosives

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  1. Piscicides, Toxicants, and Explosives

  2. Reasons for using toxicants: • Control undesirable fish in favor of sport species; e.g. suckers or carp • Eradicate exotic species; e.g., snakehead • Eradicate competitors • Control fish diseases • Restoration of endangered species

  3. Toxicants for fish sampling • Piscicides: fish poisons • Only four registered with EPA: • Rotenone • Antimycin • Two lampricides • TFM (3-trifluromethyl-4nitrophenol) • Bayer 73 (2-aminoethanol salt of 2',5-dichloro-4'-nitrosalicylanilide) • Must be applied by a certified pesticide applicator.

  4. Rotenone • • Most common; derived from root of derris plant (a legume) • • Blocks oxygen uptake across gills -> suffocation • • 1 gal/acre-ft = 3 ppm • • 2.5-5% liquid • • Powder form: difficult to get into suspension; shelf life is limited • • Toxic ~10 days at 70-75ºF (longer at colder temperatures) • Effectiveness is function of species, size, water temperature, pH, O2, suspended matter

  5. Samples entire community Low selectivity Works well in shallow areas Immediate detoxification with potassium permanganate (KMnO4) Most fish are ‘sacrificed’ Negative public perception Non-target species: swine, zooplankton, many invertebrates Drinking water concerns Potassium permanganate toxicity Pros and Cons of Rotenone

  6. Cove rotenone sampling-most common in SE U.S. Administration of rotenone-mixing with prop wash.

  7. Protocol for rotenone cove sampling: • determine cove volume • set block net (typically 3/8" mesh w/ 1/4" mesh float collar) pre-dawn or previous day • apply dilute solution w/pump at net and deep areas first; hand-spray littoral zone • Three day pickupand data collection schedule: • day 1: species, length, weight • day 2: species, length • day 3: species

  8. Block seine contains floating dead fish.

  9. Collecting poisoned fish.

  10. Evaluation of Cove Rotenoning • Pro: allows estimation of standing crop (lb/acre or kg/ha) • Biases: typically conducted in late summer, so may not get true species composition or true size structure for populations • Scuba shows that 75% of total number and 95% of biomass will surface in 3 days • Use is declining because of concerns over fish mortality

  11. Stream Rotenoning • Primarily in warm water streams • Use block nets • Determine velocity and make calculations • Use potassium permanganate, KMnO4, drip at lower end to detoxify

  12. Antimycin • Antibiotic from the fungus Streptomyces • Sold as Fintrol • Inhibits respiration at cytochrome level • Toxicity decreased by high alkalinity, temperature, sunlight • Detoxified with potassium permanganate • Affects fish selectively: can be used to ‘clean out’ catfish ponds, as it will eliminate cyprinids, catostomids, percids and centrarchids

  13. Lampricides

  14. Lampreys ascend streams to spawn

  15. Injecting lampricide into sediments to reach ammocoetes.

  16. Explosives

  17. Sampling with Explosives • • Detonating cord (PrimaCord), dynamite • • Typically used only when any other technique is difficult to apply • – e.g., too much debris, timber, etc., cannot use seines, gill nets, or hoop/trap nets • – low conductivity--cannot use electrofishing • – remote area limits amount of gear • • Safety!! Likely will be quite a few requirements

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