What's up with the baltic dry?

The baltic dry index has shed about 35% from its autumn peak, and is still about 70% off its all time peak of 2008. Compare this with copper, which, amid stories of speculative hoarding by private chinese "investors", is within a few percents of reaching records!

Considering the long-time love story between the two, a long baltic dry/short copper trade seems like an interesting bet at a six months horizon: