Evaluation of the acute toxicity of the seeds of Anamirta cocculus (Linn.) and its piscicidal effect on three species of freshwater fish
N Jothivel, V Paul
acute toxicity, piscicide
N Jothivel, V Paul. Evaluation of the acute toxicity of the seeds of Anamirta cocculus (Linn.) and its piscicidal effect on three species of freshwater fish. The Internet Journal of Toxicology. 2007 Volume 5 Number 1.
Seeds of the Indian fish berry Anamirta cocculus (Linn.) are a potential piscicidal agent used for catching fish from the wild by native people. In the present study, laboratory evaluation of the acute toxicity of the seeds of A. cocculus was done at various time intervals on three species of freshwater predatory fishes viz., Clarias batrachus (Linn.), Channa striatus (Bloch.) and Mystus vitattus (Bloch.). The piscicidal agent was administered as a stomach poison in two different modes viz., after deep-frying and without heating. The LC50(s) and LC99(s) at different durations were calculated in both the modes of administration on all the three species tested. For C. batrachus, the LC50(s) at 1, 2, 24, 48, 72 and 96 hours (h) of piscicidal administration in the heated mode was 203.8463, 170.5797, 137.785, 100.5709, 85.4432 and 62.7660 mg/kg body weight and in the without heated mode 167.2705, 101.2334, 68.4538, 63.9773, 51.6782 and 50.2421 mg/kg body weight respectively. For C. striatus, the LC50(s) at 1, 2, 24, 48, 72 and 96 h in the heated mode was 109.2334, 77.4538, 57.9773, 44.2705, 34.6782 and 24.2421 mg/kg body weight and in the without heated mode 90.7660, 55.4433, 34.5709, 28.7685, 20.5798 and 15.3158 mg/kg body weight respectively. For M. vitattus the LC50(s) at the corresponding durations in the heated mode was 32.2706, 22.4433, 19.7686, 15.2883, 7.2517 and 3.4484 mg/kg body weight and in the without heated mode 26.8463, 17.2705, 10.0193, 7.9773, 4.9850 and 1.9082 mg/kg body weight respectively. LC99(s) in both the modes of administration in the respective exposure periods for all the three species tested were also calculated. The results reveals that of all the species tested, C. batrachus is the most resistant one towards the toxicity of A. cocculus followed by C. striatus and M. vitattus. The present study has also shown that these seeds may be used as a potent aquaculture management tool to eradicate unwanted wild fish from culture ponds before stocking.
Since prehistoric times, cultures throughout the world have used piscicidal plants for fishing. According to ( 1 ), plants are virtually inexhaustible sources of structurally diverse and biologically active substances. Fossil records dates back the use of plants by human beings for various purposes including medical use at least to the middle Paleolithic age, some 60,000 years ago ( 2 ). Plants with insecticidial, piscicidal and molluscicidal properties have also been used widely by human beings ( 3 ). Fisher folks of various African countries extensively use many plants and plant products for capturing fish ( 4,5 ). Barbascos of ethanobotanical origin and their application in capturing fish have also been reported from other regions of the world such as South America ( 6 ), Nepal ( 7 ), India ( 8,9 ), etc. In addition to their use as traditional piscicidal agents for catching wild fish, plant derived fish toxicants are also used in aquaculture management for controlling the predatory and weed fishes. The eradication of these wild fishes form the culture ponds before the stocking of desired species is an important step in pond management as the former compete and/or prey upon the latter. In this aspect, the air-breathing predatory fish species are of particular importance as they are highly resistant to toxicants ( 10 ) and may survive in moist borrows and mud even when ponds are drained. The use of plant origin ichthyotoxicant as a fisheries management tool has been practiced in at least 30 countries ( 11,12,13 ). As the control and eradication of unwanted fishes in the pond require effective piscicides which are usually not easily accessible, farmers even use synthetic compounds including malachite green, sodium cyanide, antimycin, etc. and even pesticides ( 14,15,16,17 ). However, use of these compounds in culture ponds is seldom appreciated especially due to their long-term persistence in the ecosystem as well as in the cultured species. Therefore alternative piscicides such as botanicals, which are biologically degradable, and having piscicidal activities with shorter residual effects are being appreciated.
The seeds of the Indian fish berry
Materials and methods
Fishes and their maintenance
Healthy specimens of
Food and feeding
The fishes were liberally fed with minced earthworm meatballs. While
Preparation of the toxicant
The hard shells of the dried fruits of
Calculation of lethal concentrations and statistics
The mortality rates observed during the stipulated exposure periods were recorded and using this data various LC50(s) and LC99(s) were calculated by following Finney's ( 19 ) method along with the slope values. The heterogeneity of the data (if any) in each set was also checked using chi-square (χ 2 ) test.
In both the modes of administration of
Mortality rate (Figs. 1 to 6)
The average percentages of mortality of all the three species at various stages of toxicant administration in both the modes are given in Figures 1 to 6. Using these mortality rates, the LC50(s) and LC99(s) were calculated.
Lethal concentrations (Tables 1 to 6)
The respective LC50(s) of
From time immemorial, humans explored ways and means to divert poisons of biological origin to their own advantage. The pandemic need to find plants that work well as soap has been pursued by most native cultures and this experience of using various plants for their soap like properties might have lead to the universal discovery that chemicals released from some plants would also stun fish when used in a specific circumstance ( 21 ).
On the other hand, predatory and weed fishes pose serious threats to the cultured species and therefore their control is an essential part of the pond management. The problem becomes more aggravated in the case of the predatory fishes like
Usually, for harvesting fish from the wild using plant origin piscicides, the plant part to be used as piscicide is thoroughly pounded and the macerated material is thrown into the water body from which the fishes are to be harvested. In such situations, the toxicants act as contact poisons and therefore are more active in standing water bodies. However, in case of
According to Cagauan
Authors thank Annamalai University authorities for providing lab facilities and Dr. K.K. Nair, Senior Scientist, KFRI, Kerala, India for plant identification.