OSHAWA, Ontario — For many in Canada, the rise of the Canadian dollar to parity with its American counterpart is more a source of anxiety than pride.

Prominent among those concerned are the 20,600 Canadian Auto Workers union members employed by the Detroit Three. Contract talks for the industry open here on Tuesday. But the dollar’s high value, which most economists anticipate will continue, has more than obliterated the traditional cost advantage Canadian auto plants once enjoyed.

In 2009, when contracts were renegotiated after the rescue of General Motors and Chrysler, the Canadian dollar was worth about 78 American cents. Last week, it traded briefly at just over $1.

Regardless of the outcome of those talks, the strong currency, and higher wages for Canadian workers, seem likely to continue the shrinking of the Canadian auto industry since its peak in 1999. The underlying issue is how much that decline will continue.