Theoretical Ecology

, Volume 5, Issue 2, pp 283–296 | Cite as

Stocking of captive-bred fish can cause long-term population decline and gene pool replacement: predictions from a population dynamics model incorporating density-dependent mortality

  • Akiko SatakeEmail author
  • Hitoshi Araki
Original paper


Releasing captive-bred fish into natural environments (stocking) is common in fisheries worldwide. Although stocking is believed to have a positive effect on fish abundance over the short term, little is known about the long-term consequences of recurrent stocking and its influence on natural populations. In fact, there are growing concerns that genetically maladapted captive-bred fish can eventually reduce the abundance of natural population. In this study, we develop a simple model to quantitatively investigate the condition under which recurrent stocking has long-term effects on the natural population. Using a population dynamics model that takes into account a density-dependent recruitment, a gene responsible for the fitness difference between wild and captive-bred fish, and hybridization between them, we show that there is little or no contribution of recurrent stocking to the stock enhancement without a replacement of the wild gene pool by the captive-bred gene pool. The model further predicted that stocking of an intermediate level causes a reduction, rather than enhancement, of population size over the long term. The population decline due to stocking was attributed to the fitness disadvantage of captive-bred fish and strong overcompensation at recruitment stage. These results suggest that it would be difficult to simultaneously attain population size recovery and conservation of the local gene pool when captive-bred fish have fitness disadvantage in the wild, although caution is needed when applying the predictions from the simplified model to a specific species or population.


Stocking Fish Supplementation Population dynamics Genetic effect Harvest 



This work was supported by the 2007 special coordination funds for promoting science and technology of MEXT and PRESTO to A.S. and the Swiss National Science Foundation (No. 31003A_125213) to H.A. We thank Haertel-Borer S. and R. Arlinghaus for many useful comments.

Supplementary material

12080_2011_128_MOESM1_ESM.doc (3.6 mb)
ESM 1 (DOC 3674 kb)


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Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.Creative Research Initiative “Sousei”Hokkaido UniversitySapporoJapan
  2. 2.PRESTO, Japan Science and Technology AgencySaitamaJapan
  3. 3.Department of Fish Ecology and EvolutionSwiss Federal Institute of Aquatic Science and Technology (EAWAG), Center of Ecology, Evolution and BiogeochemistryKastanienbaumSwitzerland

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