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Published online: 1 July 2009 | doi:10.1038/nchina.2009.137

Environmental sciences: Dying sturgeons

Ai Lin Chun

Introduction

© (2009) istockphoto.com/Cezar Serbanescu

The Chinese sturgeon, which spawns only in the upper reaches of the Yangtze River, has in the past been harvested extensively as a prized source of caviar and is now classed as an endangered species. The construction of the Three Gorges and Gezhouba dams, however, has also destroyed much of its spawning habitat, and the sturgeon now faces extinction. Jianying Hu at Peking University in Beijing and co-workers¹ have discovered yet another problem that is contributing to the sturgeon's decline — chemical pollution.

The researchers found various organotin compounds (chemicals commonly used in ship paints) in tissues of wild Chinese sturgeons. Triphenyltin (TPT) in particular was found to be present at high concentrations (31–128 nanograms per gram, wet weight) in the liver. High concentrations of TPT were also identified in wild sturgeon eggs, suggesting that sturgeons can transfer TPT to their offspring.

The researchers studied the effect of TPT on Siberian sturgeons in place of the endangered Chinese variety. The injection of TPT into sturgeon eggs at concentrations similar to those found in the wild caused the embryos to develop deformities in a dose-dependent manner. Although other contaminants, such as polychlorinated biphenyls, might also contribute to malformations in the wild, the adverse effect of TPT was clearly reproduced in the laboratory.

The findings suggest that TPT might be contributing to the continued decline in the Chinese sturgeon, although the effects of TPT under field conditions require further investigation. Nevertheless, firmer environmental management policies and the regulation of waste disposal practices should be implemented in order to protect the endangered Chinese sturgeon.

The authors of this work are from:
College of Urban and Environmental Sciences, Peking University, Beijing, China; Key Laboratory of Freshwater Biodiversity Conservation and Utilization, Yangtze River Fisheries Research Institute and Ministry of Agriculture, Chinese Academy of Fisheries Science, Jingzhou, China; Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada; Department of Zoology, Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA; Department of Biology and Chemistry, Research Centre for Coastal Pollution and Conservation, City University of Hong Kong, Hong Kong, China; Key Laboratory of Cell Proliferation and Differentiation, Center of Developmental Biology and Genetics, College of Life Sciences, Peking University, Beijing, China.

Reference

1. Hu, J. et al. Malformations of the endangered Chinese sturgeons, Acipenser sinensis, and its causal agent. Proc. Natl Acad. Sci. USA 23, 9339–9344 (2009).
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