CHALLENGES IN AQUATIC SCIENCES Does hatchery-reared Siniperca chuatsi (Actinopterygii, Perciformes) compete significantly with two wild Siniperca populations for diets in a shallow lake? Wei Li • Brendan J. Hicks • Chuanbo Guo • Zhongjie Li • Jiashou Liu • Tanglin Zhang Received: 31 July 2013 / Accepted: 17 March 2014 / Published online: 8 April 2014 Ó Springer International Publishing Switzerland 2014 Abstract This study aimed to evaluate whether hatchery-reared Siniperca chuatsi (HSC) competes significantly with wild Siniperca populations in a shallow lake. Two wild Siniperca fishes, S. chuatsi and Siniperca kneri, along with HSC, were collected in the shallow Biandantang Lake, and their diets were determined using both stomach contents and stable isotope analyses. The stomach contents showed that shrimps and fish were the major food items of HSC and wild Siniperca fishes, but their dietary composi- tion and percentage contribution revealed significant differences. Isotopic mixing model analysis suggested similar conclusions that contribution proportions of end members were significantly different. The niche overlap index on the basis of prey importance from stomach content analysis indicated that there was not significant diet overlap between hatchery-reared and wild Siniperca populations in winter and summer. Similar results were found in winter based on the prey contributions from isotopic mixing model outputs, but meaningful diet overlap was observed in summer. Our findings demonstrated that HSC did not have apparent feeding competition with wild Siniperca fishes during the critical periods of the early stocking stages, suggesting that moderate stocking of HSC may not have a negative effect on the variability of wild Siniperca populations. Keywords Diet  Siniperca fishes  Hatchery reared  Stable isotopes  Stomach contents  Trophic interaction Introduction Stock enhancement is a fisheries management approach involving the release of cultured organisms to increase abundance and yield of natural fish or invertebrate stocks (Lorenzen, 2005). Stocking of hatchery fish has been practised on a large scale since the mid-nineteenth century. By 2010, there are 94 countries around the world to develop stock enhancement, involving more than 180 different species (FAO, 2010). In general, successful stock enhancement can improve socioeco- nomic outcomes by (1) creating new economic Guest editors: Jiang-Shiou Hwang & Koen Martens / Challenges in Aquatic Sciences W. Li  C. Guo  Z. Li  J. Liu  T. Zhang (&) State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072, China e-mail: tlzhang@ihb.ac.cn B. J. Hicks Environmental Research Institute, Faculty of Science and Engineering, The University of Waikato, Hamilton, New Zealand C. Guo University of the Chinese Academy of Sciences, Beijing 100049, China 123 Hydrobiologia (2014) 741:125–138 DOI 10.1007/s10750-014-1866-9