Kava: NOT the plant used in poison fishing.
Derris elliptica - The plant with a similar name, but not so similar function.
This one is mildly strange and a little specific, but it has been suggested on several occasions that kava was formerly employed for paralyzing fish in streams, traps, and ponds. However, this notion appears suspect as kava, even the wild or tudei variety, lacks the water-soluble toxins required for this purpose. Research has indicated that administering kavalactones to fish via water does not result in paralysis or mortality, even at considerably high dosages [1].
So, I fired up my research catalog this morning and began to read. Turns out it is not kava, but certainly makes sense why some may have thought it was. The name is similar, and the process of preparing the toxin is similar to that of kava preparation.
The original source of this misinterpretation is found in Dr. Lebot’s technical paper titled “Kavas of Vanuatu - Cultivars of Piper Methysticum Forst.” In this document Dr. Lebot states “Furthermore, it should be noted that these reputations form a coherent group, whereas the use of kava as a poison for fish (Hillebrand 1888) was noted only once, as pointed out by Stokes (1921)[9].”
If we go back to Stokes’ 1921 work we find that they speak about Hillebrand specifically, and first thing. Stokes said “Hillebrand mentioned awa as a fish poison, but no confirmation of such use is obtainable from natives today. They say that awa was used by fisherman, but ridicule the idea of wasting it on fish”. Now, if we also go back and look at Hillebrand 1888, we can see them state “Like many other plants of this order, the Hawaiian Akeas contain an acrid-narcotic principle, and are employed by the natives, in common with Awa and Auhuhu for narcotizing fish. [10]” It has been long known that Auhuhu and AKIA were used for poison fishing, and it seems this author has accidentally referenced the wrong botanical.
The plant in question, known as “Kava'Aukava” or more commonly referred to as 'Aukava, "duva," "derris powder," or "tuba root," possesses the scientific name Derris elliptica. Although two other plants, Tephrosia purpurea and Barringtonia asiatica, were used in the absence of 'Aukava [2] [3], we will focus our discussion on 'Aukava. The primary active ingredient in 'Aukava responsible for its paralytic effects on fish is the chemical rotenone [4], which is also employed as a pesticide and delousing agent [5]. The process for obtaining this chemical involves pounding the roots on a solid surface or wooden box, squeezing the roots into a bucket of water, and then releasing the contents into the river or stream [6]. The toxic impact of this chemical is exerted via the destruction of dopaminergic neurons [7].
It is good to finally put this bit of myth to rest about kava. If kava were anywhere near as potent as this rotenone compound, you would only need a drop of it in your drink. They poison entire streams and ponds with the roots of this plant. It was found that a concentration of 1 part powdered derris root to 2 million parts of water was sufficient to kill all species of fish tested [8]. This sounds nothing like the safe and gentle kava we know and love.
[1] Wang, Dongmei, Longen Yang, Jingtao Wang, Guojun Hu, Ziyuan Liu, Dongni Yan, Nazar Serikuly, et al. 2020. “Behavioral and Physiological Effects of Acute and Chronic Kava Exposure in Adult Zebrafish.” Neurotoxicology and Teratology 79 (May): 106881. https://doi.org/10.1016/j.ntt.2020.106881.
[2] Kirch, P. V., and T. S. Dye. 1979. “ETHNO-ARCHAEOLOGY AND THE DEVELOPMENT OF POLYNESIAN FISHING STRATEGIES.” The Journal of the Polynesian Society. Polynesian Society 88 (1): 53–76. http://www.jstor.org/stable/20705394.
[3] Tavana, Gaugau, Patricia Stewart, Diane Ragone, Krisa Fredrickson, Paul Cox, and Joan Borel. 2003. “Lack of Evidence of Kava-Related Hepatotoxicity in Native Populations in Savaii, Samoa.” The Journal of the American Botanical Council 2003 (59): 28–32. https://www.herbalgram.org/media/12000/issue59.pdf.
[4] Zubairi, Saiful Irwan, Zetty Shafiqa Othman, Mohamad Roji Sarmidi, and Ramlan Abdul Aziz. 2016. “Environmental Friendly Bio-Pesticide Rotenone Extracted from Derris Sp.: A Review on the Extraction Method, Toxicity and Field Effectiveness.” Jurnal Teknologi 78 (8). https://journals.utm.my/jurnalteknologi/article/view/5942
[5] Wood, David Michael, Hadi Alsahaf, Peter Streete, Paul Ivor Dargan, and Alison Linda Jones. 2005. “Fatality after Deliberate Ingestion of the Pesticide Rotenone: A Case Report.” Critical Care / the Society of Critical Care Medicine 9 (3): R280–84. https://doi.org/10.1186/cc3528.
[6] II. milkfish farming practices. Potential of milkfish farming development in fiji. (n.d.). Retrieved March 2, 2022, from https://www.fao.org/3/ac893e/AC893E03.htm
[7] Alam, M., and W. J. Schmidt. 2002. “Rotenone Destroys Dopaminergic Neurons and Induces Parkinsonian Symptoms in Rats.” Behavioural Brain Research 136 (1): 317–24. https://doi.org/10.1016/s0166-4328(02)00180-8.
[8] Leonard, J. W. (n.d.). Notes on the use of Derris as a fish poison. (fisheries research report: 479). Retrieved March 2, 2022, from https://quod.lib.umich.edu/f/fishery/AAG2862.0479.001
[9] Stokes, John F. G. 1921. “Fish Poisoning in the Hawaiian Islands.” Bishop Museum Press.
[10] Hillebrand, W. F. 1888. Flora of Hawaiian Islands.