Piscicide

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A piscicide is a chemical substance that is poisonous for fish and that is used deliberately and specifically to poison them. The term is mostly used as a sub-category for a biocide directed against fish, but it is also used in connection with poisonous fish using toxins . The adjective piscizid is, exceptionally and very rarely, also used to characterize substances that are toxic to fish in general (more often: ichthyotoxic). In the biocide directive of the EU (see below) the expression fish control agent is used in the same sense .

Poison fishing

Catching fish by stunning using a, usually vegetable, toxin is now officially prohibited in industrialized countries, but it has traditionally been and is still practiced in numerous indigenous peoples around the world. From Africa alone, 325 plant species from 183 genera and 71 families have been identified for this purpose, with legumes s. l. and milkweed plants dominate. From India 112 species are given for this use. In addition to the Albizia species common in Africa (subfamily of the mimosa family in the legume family), the fruits of Diospyros lanceaefolia ( ebony family ), but also the walnut ( Juglans regia ), which is widespread in Europe , are used most frequently (effective only unripe fruits when fresh).

The secondary plant substances responsible for the effect are u. a. terpenoid saponins and Rotenoids , di-, tri- and sesquiterpenes , furocoumarins , phenylpropanoids and quinones . Plant substances are selected that are harmless to humans when they eat the fish. An exception is picrotoxin , which is obtained from the fruit of the pseudo myrtle ( Anamirta cocculus ).

Piscicides as biocides

Piscicides are used in the fishing industry to push back unwanted fish species that are in competition with economically important species or to exterminate them locally or to prevent sick fish escaping from infected stocks from spreading. Sometimes they are used to exterminate the resident predatory fish population before a pond is stocked. Another field of application is the control of introduced, neozoic fish species, when these are still rare and locally distributed, but a rapid spread is feared.

Although a variety of substances were tested, and also partly used, the most significant far piscicide commercially worldwide used is different from the roots of tropical Schmetterlingsblütler obtained rotenone . Rotenone is widespread in the family and can be obtained from both East Asian and South American plant species. In East Asia, for example, the roots of the tuba root ( Derris elliptica ), a native to Borneo , are used, in America Deguelia utilis as well as Lonchocarpus and Tephrosia species, all of which are called Barbasco here (after Verbascum , the mullein , whose seeds used to be served as fish poison in Europe). Rotenone works by obstructing breathing: it specifically inhibits complex I of the respiratory chain in mitochondria . Rotenone acts on fish species such as pike , perch or eel and trout in concentrations of 0.05 milligrams per liter of water. It is also poisonous to warm-blooded animals, but its toxicity is lower. The LD 50 for oral intake for birds such as Mallard is about 1 gram per kilogram in rabbits 1.5 grams, at domestic dog three grams. The toxicity for amphibians is in the same order of magnitude as for fish. Applied in water, Rotenone is broken down in about two weeks, depending on the temperature. The degradation can be accelerated by adding permanganates . Lethal doses of 300 to 500 mg / kg for adults and 143 mg / kg for children are given in humans. The main risk is for the user himself who accidentally inhales the active ingredient used as a powder or spray.

Another common piscicide is the later developed antimycin A, an antibiotic that is synthesized by fungi of the genus Streptomyces . The poisonous effect is very dependent on the type of fish, from 0.8 micrograms per liter z. B. in rainbow trout up to 100 micrograms per liter, z. B. goldfish .

Nothing is known with certainty about the effect of piscicides on the aquatic community, especially the aquatic invertebrates at the base of the food chains, and studies on the long-term effect are completely lacking. The available studies classify the effect in the entire spectrum between negligible to strong, significant effects.

Use of piscicides

United States

In the United States , Rotenone is widely used for fisheries management. In the last few decades, its use has been widely criticized and locally banned. In a survey carried out between 1988 and 1997, 48 out of 78 fishing agencies that took part indicated that they used Rotenone. Seven others had used it earlier, but stopped using it due to new laws or guidelines. In one reservoir alone, the Strawberry Reservoir in Utah, 20,000 kilograms of the active ingredient were used in one year (1990). Around half of the operations were in favor of sport fishing.

Europe

In the EU Biocide Directive (Directive 98/8 / EC of the European Parliament and of the Council of February 16, 1998 on the placing of biocidal products on the market), Appendix V (biocidal product types) under product type 17 lists "fish control agents". The guideline regulates the authorization and the placing on the market of biocides, and thus also piscicides. According to Article 4 of the Directive, the European Union can determine biocidal products that are to be approved in all member states after approval in one member state, but has not yet done this in the case of piscicides. The national approval is therefore still decisive for this.

In Germany, the relevant legal regulation is the Chemicals Act , Section IIa. According to § 4 of the ordinance on the approval of biocidal products and other chemical law processes for biocidal products and biocidal active substances (Biocide Approval Ordinance - ChemBiozidZulV) of July 4, 2002, approval for piscicides may not be granted in Germany. Their use in Germany is therefore generally prohibited.

In Switzerland, approval is regulated in the Chemicals Act. According to Article 4 of the Biocidal Products Ordinance, fish control products are neither authorized nor registered. Exceptions for research and development purposes are possible.

The relevant legal basis in Austria is the federal law for the implementation of the Biocidal Products Ordinance (Biocidal Products Act). According to Section 14 (4) of the Act, the approval of fish control agents is not permitted here.

See also

Individual evidence

  1. ^ HD Neuwinger (2004): Plants used for poison fishing in tropical Africa. Toxicon Volume 44, Issue 4: 417-430 doi : 10.1016 / j.toxicon.2004.05.014
  2. ↑ RN Chopra, IC Chopra, KL Handa, LD Kapur: Chopra's indigenous drugs of India. second edition. Dhur et Sons, Calcutta, 1958. p. 395.
  3. ^ R. Dominic & SN Ramanujam (2012): Traditional knowledge and ethnobotanical use of piscidal plants of Nagaland, North east India. Indian Journal of Natural Products and Resources Vol. 3 (4): 582-588.
  4. ↑ Jonathan G. Cannon, Robert A. Burton, Steven G. Wood, Noel L. Owen (2004): Naturally Occurring Fish Poisons from Plants. Journal of Chemical Education vol. 81, no. 10: 1457-1461.
  5. ↑ a b B.R. Morrison: Use and Effect of Piscicides. In: Angling an wildlife in fresh waters. ITE symposium no. 19. Proceedings of a symposium organized by the Scottish Freshwater Group and the British Ecological Society University of Stirling, October 30, 1985. edited by PS Maitland & AK Turner. Cambridge, 1987, pp. 47-52
  6. ↑ Rotenone as a piscicid (Eng.).
  7. ↑ Krithika Muthukumaran, Alyson J. Laframboise, Siyaram Pandey: Herbicides and the Risk of Neurodegenerative Disease. In: Herbicides - Mechanisms and Mode of Action. Edited by Mohammed Naguib Abd El-Ghany Hasaneen. InTech, Rijeka 2001, ISBN 978-953-307-744-4 .
  8. ↑ Rotenone, the fish killer, by Dana Sackett. The fisheries blog .
  9. ↑ Mark R. Vinson, Eric C. Dinger, Deanna K. Vinson (2010): Piscicides and Invertebrates: After 70 Years, Does Anyone Really Know? Fisheries Volume 35, Issue 2: 61-712. doi : 10.1577 / 1548-8446-35.2.61
  10. ↑ Rotenone Stewardship Program ( Memento of the original dated November 10, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / www.fisheries.org
  11. ↑ William McClay (2000): rotenone use in North America (1988-1997). Fisheries Volume 25, Issue 5: 15-21.
  12. ↑ Directive 98/8 / EC of the European Parliament and of the Council of February 16, 1998 on the placing of biocidal products on the market .
  13. ↑ Ordinance on the approval of biocidal products and other chemical law processes for biocidal products and active biocidal substances (Biocide Approval Ordinance - ChemBiozidZulV) .
  14. ↑ Ordinance on the placing on the market of and handling of biocidal products (Biocidal Products Ordinance, VBP) .