If you can't tell looking at in the flesh, I certainly can't from a photo.

Given the direction of the crack, try removing the wheel and gently flexing the blades apart like a wishbone, while watching the crack. Any movement, or spreading and the fork is toast.

If this were any other part of the frame, I'd probably say ride it and monitor it daily for any change. However, I'm much more conservative about forks, since there's no redundancy, and any failure will have sever consequences. For that reason, I wouldn't ride it until the maker certified that it's safe. In all likelihood they won't want to take the financial risk an injury would involve and rather than certify it safe, would replace it and get it off the road.