Piscicidal activity of methanolic extract of Capparis stylosa on the freshwater fish Channa punctatus (Bloch.)
G Ambedkar, M Muniyan
methanolic extract, piscicidal activity
G Ambedkar, M Muniyan. Piscicidal activity of methanolic extract of Capparis stylosa on the freshwater fish Channa punctatus (Bloch.). The Internet Journal of Toxicology. 2008 Volume 6 Number 1.
Laboratory evaluations were made to asses the piscicidal activity of methanolic extract of
The presence of predatory and weed fishes in cultured pond is a serious problem for culturing edible freshwater fishes. These fishes adversely affect the cultured fish population in culture pond by sharing food and habitat of major cultivated carps.
A large number of plants belonging to different families  and their products  have been used for controlling unwanted fish population not only in India but also all over world . The toxicity of plant extract to the fresh waterfish have been studied by number of investigators . But the piscicidal activity of
Materials and methods
Collection and preparation of extract of Capparis stylosa root
Collection and storage of experimental animals
The toxicity experiments was performed by the standard method . The fishes were exposed for 24, 48, 72 and 96 hours at different concentration of methanolic root extract. Mortality was recorded at every 24 hr upto 96 hr exposure period. Fishes were considered dead if they failed to respond to stimulus provided with glass rod. The recorded mortality data was used to calculate the LC50 values, upper and lower confidence limits slope function and regression results according to probit log method . The presumable harmless concentration of the toxicant was calculated using the formula given by Sprague .
Acute toxicity studies of the Capparis stylosa root extract on Channa punctatus
The acute toxicity studies of root extract
The slope functions were 1.3423, 1.3139, 1.3217, 1.999 for 24, 48, 72, 96 hr respectively. The regression equations were Y = 0.0972 x + 0.0087; Y = 0.1004 x – 0.00174; Y = 0.0998 x + 0.001; Y = 0.0998 x – 0.00061 for 24, 48, 72 and 96 hr respectively. The chi-square values were 0.740, 3.498, 1.566 and 0.431 for 24, 48, 72 and 96 hr. These chi-square values denote that there was no significant different between observed and expected mortality during the acute toxicity study.
The toxicity study shows the overall picture of test progress and indicates that the rate of mortality increased with increasing concentration of plant extract in a linear fashion. The presumable harmless concentration of the plant extract to the fish,
Behaviour studies of the Capparis stylosa root extract on Channa punctatus
During acute toxicity studies of exposures to methanol root extract of
The toxicity data of the present study indicate that the significant positive correlation between dose and mortality. It may be due to increased concentration of extract in trough water and resulted in more intake or entry of active moieties in the fish body. This trend is also dependent on several factors such as, rate of penetration, nature of slope, variability of active moieties, etc. .
The steep slope values indicate that there is a large increase in the mortality of fishes with relatively small increase in the dose of different treatments. There is no significant different between observed and expected mortality. Since calculated chi-square values are less than the table chi-square value. Thus, it is expected that
Toxicity experiments showed that methanol extract of
The potential for using root extract of
The control and eradication of unwanted fishes in the pond requires the use of effective piscicides. Most of the fish farmers resort to the use of chemical piscicides that prove to be very effective although these chemicals are rather dangerous to the environment and can do more harm than good. Alternative piscicides that are not hazardous to the environment and have shorter residual effects must be used. The results of the study showed that locally available plants to be used as piscicide which can be an alternative to harmful chemical piscicides that can be widely used today to eradicate unwanted fishes in the ponds.
Further studies must be conducted to suitability of the extract on other species of the ecosystem. The use of other extraction methods and other predatory fishes must be considered in future investigations.
The authors are thankful to the Professor and Head, Department of Zoology, Annamalai University for providing necessary facilities, during the investigation.
Dr. M. Muniyan Lecturer (Senior Scale) Department of Zoology Annamalai University Annamalainagar 608 002 Tamilnadu, India e-mail: firstname.lastname@example.org Mobile: (0091) 9443922385