Mink Release Study

26/11/09

A recent paper published April 2009 studies the survival rate of captive-bred mink. The study tracked the survival of captive-bred mink over eight years.

The study set out to answer the following questions:

1. What is the survival rate of released mink and how does it
change with time since release?
2. Do age, sex of an individual, and the conditions in which it is
kept prior to release, affect its subsequent survival in the wild?
3. What are causes of mortality?

A few of the factors which could mitigate the relevance of this study are:
*The study was done with endangered European mink, not the commonly farmed North American mink.
*The study did not specify how many generations the mink had been bred in captivity (though, as reprinted below, it concluded this was not relevant to survival).

A few highlights:

*"There was no evidence that the number of generations for which the lineage of the released individuals had been bred in captivity had any effect on survival."

*Released mink survived for "up to 39 months"

*"The main cause of death was other carnivores and raptors, although this broad categorization may conceal a diversity of fatal scenarios."

*(Only)"...three deaths were caused by humans: one was shot, the second was hit by a car and the third was beaten to death when venturing into a farmyard."

*A quarter of the released European mink died within the first ten days. Survival decreased by half in 38 days and then stabilised....Overall, we conclude that mink adapt to the wild c. 1–1.5 months after release."

*No mink were found to have died (directly) due to lack of survival skills. However, "although predators are the proximate cause of death, the ultimate causes may be a syndrome of mal-adaptations."

*"The results show that genetically managed, long-term breeding programs within the zoo community can be a source of individuals for re-introductions".

The study cites past studies on the release of captive-bred ferrets, otters, weasels, and fox, which may be of interest to people on this list.

The study includes graphs charting survival rates and more.

PDF of the study here: http://www.scribd.com/full/23185897?access_key=key-3dw3eoopk5rogy7zvyt

 

Similar Study:

Survival rates of free-ranging farm mink suggest quick behavioural adaptation to natural conditions. M. Hammershøj & M.C. Forchhammer

pdf: http://www2.dmu.dk/1_viden/2_Publikationer/3_Ovrige/rapporter/Phd_MHA.pdf

 

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