Lakes have been facing a number of disadvantageous eco-environmental issues due to the aggravation of human activities and the global climate change.So

lake dynamic monitoring becomes more and more important.The extraction of lake enclosure culture area as an important content for lake dynamic monitoring has been highly valued.However

few researches on extracting lake enclosure culture area have been conducted

and little attention has been paid to the extraction method

and the extraction precisions using existed methods were unfavorable.In order to improve the extraction precision of lake enclosure culture area

a new method using correspondence analysis（CA） to extract lake enclosure culture area is proposed in this paper.The CA method relies on squared deviations between pixel values and their expected values（joint probabilities）

and it explores the relationship between not only the image bands but also the pixels.Although CA has routinely been an accepted technique among ecologists and statisticians

its application to remote sensing is still relatively new.It is the goal of this study to detail CA methodology as a means of achieving highly accurate and efficient lake enclosure culture extraction.The methodology mainly includes four steps as follows: Firstly

the data is preprocessing.Secondly

the preprocessed data is transformed using the CA algorithm.Thirdly

the texture analysis is applied to the CA first component.Finally

the enclosure culture area is extracted by decision tree according to the most superexcellent threshold value.In this study

the Gehu lake is selected as a case to validate this method based on the multi-spectral data of Landsat-7 ETM+ acquired on July 26

2001

which is obtained in a standardized orthorectified GeoTIFF format downloaded from internet.The Gehu Lake（31°29′—31°42′N

119°44′—119°53′E） is located in the middle and lower reaches of the Yangtze River

which is the second largest lake in Taihu basin

and its water area is 146.0 km2.It is one of the earliest lakes which utilized the enclosure culture to cultivate freshwater fish or shellfish.And the classification results are evaluated using the precision analysis function in ENVI4.2.The results are as follows:（1） the extraction accuracy of enclosure culture area is 95.59%

overall accuracy is 91.14%

with overall Kappa value of 0.86;and（2） the area of Gehu lake enclosure culture is 111.76km2

76.29% of total Gehu lake area.Then the results are compared with those with the other three methods

namely

the method based on principal component analysis（PCA）

the method combining the PCA first two components with band 4 and the method based on original bands without CA or PCA analysis.And the results of the comparison test showed that:（1） the overall accuracies for the three methods above mentioned are 82.17%、89.17% and 83.54% respectively;and（2） the classification accuracies are obvious less than that based on CA transformation.To sum up

the CA is proved to be a new powerful multivariate analysis technique for extracting enclosure culture area.But there is still some commission and omission phenomenon

such as the higher commission phenomenon in the classification of lake enclosure culture area with the commission error of 13.41%

as well as the higher omission phenomenon in the classification of the other category with omission of 21.43%.So it is necessary to improve the method to reduce the commission and omission error.And the further research should be done to test the CA method on other lakes for extraction of enclosure culture

and should also be focus on whether it can be suitable for application to high spatial resolution imagery

such as SPOT

IKONOS and QUICKBIRD.