It seems to be just Surface Ship Models in particular.
Even using a Giant-rate/Material-rate boost with a Good Fishing Rod doesn't give any drops at all.
Compared to other area unique items, Surface Ship Models seem to have a ridiculously low rate.
I feel that this could be a bug.
I'm not saying this in rage or anything, it's just that as a player that gathers a lot, it's become apparent that there's something wrong about the rate. It's actually so low that it is the only material that I would skip on dailies.
(I own and manage 20 characters, so my data pool is quite large.)