Per:

https://answers.atlassian.com/questions/9874256/why-does-fisheye-show-my-last-commit-date-as-31-dec-69

When indexing a subversion repository from a recent revision, fisheye creates a fake initial commit. However, that commit has the date of 1970. See the pics attached to the issue on answers.

This was observed when importing repository with tag and branch information.