WANG Jun-na 1, LI Chong 2, DUAN Xin-bin 3, LIAO Wen-gen 4

(1. China Institute of Water Resources and Hydropower Research, Beijing 100038, China; 2 . China Three Gorges Corporation, Beijing 100038, China; 3. Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China; 4. General Institute of Water Resources and Hydropower Planning and Design, Ministry of Water Resources, Beijing 100120, China)

Abstract: Environmental factors affecting larval abundance of the four major Chinese carps in the middle and upper reaches of the Yangtze River can be classified into four categories: meteorology, hydrology, water temperature, and sediment concentration. Out of total 15 environmental factors, the authors, by using genetic programming, identified the two most significant factors: the duration (Tdur) and the average daily rate (Qrtav) of flow increase. With a non-linear correlation, the larval abundance increases significantly with Tdur when Tdur is within 5 to 8 days. With an approximately linear correlation, the larval abundance increases with Qrtav when Qrtav <2 000 (m 3 /s) /d. Field data are not sufficient to support any conclusion when Qrtav >2 000 (m 3 /s) /d. Compared to other quantitative correlation analyses such as multiple linear regression and artificial neutral network, genetic programming has advantages in dealing with a large number of nonlinear factors especially when their affecting mechanisms are not clear.

Key words: genetic programming; fish abundance; significant environmental factors; the four major Chinese carps; duration of flow increase; average daily rate of flow increase

Published in: Journal of Hydraulic Engineering, Vol. 43, No. 7, 2012