I hadn't played water nations much until recently, except for some subbing, and I think I've been pretty inefficient in my site searching.
From Edit's DB it looks like sites are pretty sparse in the oceans.  No blood of course, and:
In Sea: 
Code:
Path    Highest level
----    -------------
B       None
HF      1
DN      2
AWES    3
In Deep Sea: 
Code:
Path    Highest level
----    -------------
BHA     None
FDN     1 *
W       2
ES      3
* According to DB, should be "none", but is at least 1.
I really should have done this about 20 turns ago 

.
Edit: Took a look at my game, and I think there are more deep sea sites than the DB suggests.  Update coming soon...