[note: although Paraderris elliptica has more recently become the preferred binomial of some botanists, e.g., see Lichvar et al. (2016), here we recognize Derris elliptica as a widely spread, species that sometimes becomes invasive and has been used in many areas as a source of fish poison and pesticide]

Micronesian Names by Islands or Island Groups: Dub, Duub or Deris (Palau), Yuub or Yub (Yap), Bagin or Tuba (Mariana Islands), Uup, Wúúp or Wúún (Chuuk), Uup (Namoluk), Up (Namonuito), Peinuhp, Einuhp, Uhp, Upanai, Upanyap or Upkesetik (Pohnpei), Op, Oop or Up (Kosrae), Te obu (Banaba)

Description: Derris is a genus of many species of woody vines or lianas and trees that are native to Old World (e.g., see Bailey and Bailey 1976; Sirichamorn et al. 2012). Derris elliptica, here assumed to be an alien species in Micronesia, is a close botanical relative of D. trifoliata, anative species in parts of Micronesia with traditional uses in this region (see below); both D. elliptica and D. trifoliata belong to Fabaceae, the bean or legume family. D. elliptica is often confused with Derris malaccensis, commonly known as the New Guinea Creeper; D. malacensis is also widely cultivated and occasionally naturalized in the Pacific (see PIER 2002). D. elliptica is a large sprawling, climber or liana (woody vine) that can reach over 10 m (30 ft) in length. Its branches are densely covered with brown hairs, and its compound leaves are about 15 cm (6 in) long with 4-6 pairs of leaflets that are obovate-oblong (i.e., they have an elongated form but are teardrop-shaped with the stem attached to the tapering point). The undersides of the leaves are brownish and silky. The flowers are borne in stalked clusters of three racemes up to about 30 cm (~1 ft) long with pinkish to bright red petals (racemes are flower clusters with “separate flowers attached by short equal stalks at equal distances along a central stem”). The fruits (pods) of D. elliptica are oblong or oblong-elliptical and up to about 7.5 cm (3 in) long with narrow “wings.” Each pod contains 1 to 3 olive, brown or black seeds that are flat and reniform. As an aggressive woody vine, D. elliptica is capable of reproducing both vegetatively and by seeds. The roots of D. elliptica plants contain the insecticide Rotenone which is used widely as a fish poison and cultivated in some areas for the horticulture industry (see below for more detail).

Distribution: Apparently from early times, the root of Derris elliptica has been used as fish poison in much of mainland and insular Southeast Asia. Indeed, D. elliptica is believed to be native to some areas in the eastern part of South Asia, and much of mainland and insular Southeast Asia. For example, Merrill (1923:299) reported it growing abundantly as a rambling climber amongst “thickets along streams, secondary forests, etc., at low and medium altitudes” in the Philippines (also see Sirichamorn et al. 2012, Bailey and Bailey 1976). In all of Micronesia, D. elliptica is most probably an alien or introduced sprawling, woody plant species, and as it has in many other tropical areas, it was brought into the region by humans, especially during the period of Japanese government control. D. elliptica is found growing wild near wetlands, as well as in forested areas inland, and can be an aggressive vine that smothers other plants and other objects as it spreads. For example, as an invasive species it has been reportedly “observed climbing over small trees and shrubs on Rota,” and it has been recorded as a problematic weedy species from many other islands in the Marianas and other Micronesian Islands, especially on the higher islands (e.g., see http://www.hear.org/pier/species/derris_elliptica.htm).

Uses by Island and Island Group: This Derris species is cultivated or collected as a wild growing plant in some tropical regions for its production of “fish poison.” Some fishermen have practiced a form of fishing in which they crush the roots of D. elliptica and throw them into the water; and subsequently fish that are stunned or dead float to the surface where they can be easily reached and harvested. Rotenone is the toxic pesticide which is found in the roots of the D. elliptica vine and whose content varies from 1.6–10.0% (e.g., Thothathri 1982:17). These roots are commonly known as “derris or tuba root of commerce” (e.g., see Sirichamorn et al. 2012:432). Rotenone is a respiratory inhibitor which kills fish by depriving them of oxygen exchange (e.g., Eldredge 1987). Although Rotenone affects most species of fin fish, many aquatic invertebrates (e.g., shell fish) appear to be unaffected by it (e.g., Des Rochers 1992:11). Derris roots have been used as a fish poison traditionally and in modern situations over a wide geographical range; the white milky exuded sap from the pounded roots is the raw material for stunning and catching fish, but today it is not allowed in many areas because all, or at least most of the fish in areas where it is applied are disabled and harvested in mass, and thus it has often been exploited widely for commercial fishing purposes. On the other hand, the native people in parts of Southeast Asia have also traditionally used the exuded sap from the roots of D. elliptica as an arrow-poison for hunting terrestrial animals, as well as for fish poison (see Iwasa 1975, Etoh 2001; also see http://www.stuartxchange.com/Tubli.html). Generally in Micronesia, the use of D. elliptica root extracts have been strongly condemned due to their impact on viable fishing; for example, “Destructive and unsustainable fishing methods – e.g. dynamite, chlorine, fish poisoning plant (Derris elliptica), and small mesh gillnets” are listed as a key threat in the “Over Exploitation and Unsustainable Harvesting Methods and Practices” for governmentally protected natural areas of the Federated States of Micronesia (see the FSM National Action Plan for PoWPA, the Programme of Work on Protected Areas; http://www.cbd.int/protected/implementation/actionplans/).

Uses in Palau: Yasuhei Ashizawa (1958:95), who had been the director of the Tropical Industries Research Institute on Palau from 1936-1944, indicated that Derris elliptica was “planted at Koror Experiment Station and Babelthuap Forestry Experiment Station.” Thus we may assume that these introductions of D. elliptica thus took place in the first half of the 20th century on both Palau by the Japanese Administration. According to Barnett (1960:29), Derris elliptica was employed to poison (actually stun) and harvest reef fish in Palau, but was used more commonly for fun and amusement rather than as “man’s work.”  Barnett indicated that normally two or three people cooperated in the collection of the vine’s leaves, which were then mashed in sand and subsequently the mixture thrown out over pools of still water, and as a result, “The lifeless fish soon begin to float to the surface and can be landed with a flick of a paddle.” The Palauan name for the D. elliptica plantand the fish poison extracted from its leaves and/or roots is Dub, which is also now the name of dynamite or other explosives used illegally to kill or stun many fish at one time in the ocean surrounding the islands of Palau (e.g., see http://www.trussel2.com/pal/pal-d.htm). According to Johannes (1981:66), citing Abe (1938), reportedly, there were four species of fish poison plants used in Palau (these include D. elliptica, Callicarpa cana, Pangium edule and Barringtonia asiatica); however, as far as Johannes “could determine only one, Derris elliptica, is still used occasionally today.” Johannes (1981:13) indicated that the “Japanese imported [D. elliptica], a more potent variety than the indigenous Derris trifoliata, and raised it commercially in Palau for the manufacture of insecticides,” and that they “also encouraged its use by Palauans to secure fish for them” (also see Ashizawa 1954 & 1958). Although “Derris root [dub] and other poisonous plants were used to poison reef fish,” it was also known among the Palauans “that too much dub applied in the vicinity of corals would kill them — and that when the corals were dead the number of fish in the vicinity would often diminish.” As a result, traditionally “young fishermen were taught not to tuck their bundles of dub under coral heads” This and other information was provided to Johannes (1981: xiii, 66), by one of his major informants, Ngiraklang, “second chief of Ngeremlengui and one of Micronesia's finest native scholars.” On the other hand, Johannes, citing (Kramer 1929), indicated that “Hundreds of bundles of dub were used occasionally to collect fish for feasts…and that this larger-scaled poisoning kills all sizes of fish and therefore undoubtedly took a large toll of juveniles.” Johannes (1981:30) also described the more modern, and devastating fabrication of dangerous powder explosives such as dynamite, that are also referred to as “dub” in Palau:

“A fish bomb is made by packing a beer can about two-thirds full with powder. The fuse is made from match head shavings that are tamped down firmly into a thin bamboo rod using a thin stick. The fuse is stuck into the powder and the can is then sealed with a layer of mangrove mud. The length of the fuse is adjusted so that the bomb will explode at a depth appropriate for the school of fish being sought. Over the years, according to Ngiraklang, at least eight men have been killed by premature explosions when making or using fish bombs. Others have lost extremities or eyes.”

Furthermore, Johannes (1981:31) pointed out that unlike excessive use of Derris fish poison preparations, dynamite “fish bombs” not only kill target fish, AND many juveniles, but also is very destructive to the reef habitat upon which fish and other marine organisms depend for their sustenance and shelter.

“As a consequence of [their] wartime use, fish stocks declined drastically [in Palau] according to Ngiraklang and other old men who were among those who used dynamite. Its use was made illegal (with the blessings of most of these men) after the war. But abandoned ammunition caches and unexploded bombs provided dynamite for some less principled fishermen for many years. Palauans said that in the early 1970s there were still caches of wartime dynamite carefully hoarded for dynamite fishing. Other sources, such as the Public Works Department, are also now available and the practice continues, albeit less often than in the past. Public opinion is increasingly against dynamite fishing and so it is restricted mainly to the districts of Koror and Peleliu where numerous islands and bays enable fishermen to use it unobserved and unheard” (for more detail on the use of D. elliptica in Palau, see Takeda and Mad 1996).

An additional damaging and unlawful technique for catching relatively large amounts of fish quickly that has been used widely in tropical regions “involves pouring bottles of hypochlorite bleach into coral heads and caves, thereby not only killing the fish therein but everything else in the vicinity.” However, according to Johannes (1981:31) “this method seems only rarely to be used in Palau today.” From a more positive perspective, in addition to its use as a fishpoison or inspiration for use of modern explosives, D. elliptica also has been used for medicinal purposes in Palau. According to Okabe (see Defillips et al. 1988), root decoctions of D. elliptica mixed with coconut oil were spread onto skin that had developed very itchy lumps (“prurigo-affected skin”) in order to relieve burning sensations as well to treat ringworm; furthermore, the juice extracted from crushed D. elliptica root has been used reportedly to eliminate “crab-lice” by applying it to the affected hair which was “then washed in sea water.”

Uses in Yap: Swamp forest species growing along streams on Yap do not generally cover extensive areas, but among the woody species characteristic of these riverine areas in wet inland depres­sions include the alien Derris elliptica (Falanruw et al. 1987:6). The roots of Yuub or Yub plants (D. elliptica) in Yap are pounded on the rocks, and then the squeezed plant parts are put in a place where fish are found; subsequently, all the fish in the vicinity become paralyzed and are  are caught easily by hand or speared (e.g., see Takeda 2001). Today, it is against the law for the public in Yap to use D. elliptica for poison, but a few villages can use it because of tradition. Although all parts of the Yuub plant may be used in medicine, the poisonous roots are not used to make those kinds of medicine that will be drunk or eaten. Stems of D. elliptica are said to have been used to make a strong cold medicine; and according to Okabe (see Defillips et al. 1988), “Young leaves are crushed, and the juice is spread on a cut.” Yuub (D. elliptica) is a close botanical relative of Derris trifoliata, known in Yapese as Gabatior Gabach; both of these species belong to the botanical genus Derris in the bean family, Fabaceae.

Uses in the Mariana Islands: Derris elliptica, known as Bagin or Tuba on Guam and sometimes referred to as Deris in the northern Marianas, is an introduced species in these islands; Although D. elliptica is illegal to cultivate or to engage in fish poisoning on Guam, Stone (1970:330-331) referred to it as cultivated but only rarely. As an invasive species in the Mariana Islands, D. elliptica has been reportedly “observed climbing over small trees and shrubs on Rota” and recorded from other islands in the northern Marianas (see http://www.hear.org/pier/species/derris_elliptica.htm).

Uses in Chuuk: The roots and stems of Derris elliptica, known as Wúúp in Chuuk, are reportedly used for fish poison by islanders living in this “almost atoll.” In addition, the long stems (wúpen) of the D. elliptica vine are utilized “as rope to haul logs” (Goodenough and Sugita 1980:389). In a review of “Forest Highlights 2011” (April 2012:3), published by the Pacific Region of the USDA Forest Service, it was reported thatan extract of D. elliptica, a “a local pesticide,” was being used to help control a “Citrus fungus disease has been impacting vegetation on Chuuk,” and that this Derris-based pesticide had been tested by the Development of Sustainable Agriculture in the Pacific (DSAP), formerly under the Secretariat of the Pacific Community (SPC)” (see
https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5366605.pdf). More recently, Manner (2013:236) reported that pounded roots of D. elliptica “are used as a fish poison” on Romonum Island in the Chuuk Lagoon.

Uses on Namoluk Atoll: The D. elliptica vine, known as Up on Namoluk Atoll, is found only in deeply shaded, overgrown areas near the center of the islets of this atoll. Formerly, the roots of D. elliptica were pounded and used to stun fish in tide pools so that they could be easily gathered (Girschner 1921:153). According to Marshall (1975:36), the stems of Up reportedly“have medicinal properties” that are recognized by people on Namoluk Atoll.

Uses in Pohnpei: Ragone et al. (2001: see Appendix 1) listed D. elliptica as one of those introduced plants that was brought to Pohnpei Island before the Japanese administrative takeover in 1914, but that the exact date of introduction is not known; these authors also listed the use of this plant as an “ornamental.” Today, there are a number of reported local names for D. elliptica in Pohnpei (see above). As in several other Micronesian island areas, the roots of this vine have been used as a source of effective, but potentially destructive fish poison.  

Uses in Kosrae: Derris elliptica is one of several woody vine species in the forests of Kosrae; for example, Hosokawa (1954:356), based on his intermittent field work in Micronesia from1933-1941, listed D. elliptica as one of “about 7 species” of lianas in the Campnosperma dominated rain forests of Kosrae. According to Hosokawa, the predominant liana in these Kosraean forests is Freycinetia ponapensis Martelli, a root-climber, that grows mainly by attaching its stems along trunks of large trees, along with several other subordinate climbing liana species, including D. elliptica, or which most of the individuals usually climb up to the canopy. The roots of the alien D. elliptica liana, known as “op”on Kosrae, are also sometimes used as a source of fish poison in Kosrae: “Nga opkihn op lom ah” (poison or kill with sap from the root of op; see Lee 1987:92). In addition, the stem of the sprawling, D. elliptica is occasionally used as cordage to fasten bundles of Nipa palm (Nypa fruticans) fronds, or to bind mangrove crabs when the common Hibiscus (Hibiscus tiliaceus)fiber is not available on this island.