DOJF (Hosking)

Ref says it has to be sliced, so raw whole oysters and chunks of fish are not really sashimi. All the JEs (GG5, etc.)just say "raw sliced fish."

@@ -21,1 +21,1 @@
-<gloss>sashimi (sliced raw fish fillet)</gloss>
+<gloss>sashimi (raw sliced fish, shellfish or crustaceans)</gloss>

Yeah, the definition only approximates the most common aspects of sashimi. 
I would certainly like the explanation to be more detailed, if possible.
First, about the "slices": on Yonaguni Island (there may be other places, but i 
haven't traveled enough to know), sashimi does not come in "slices" but in 
"chunks" (resembling cubes). And if the ingredient animals are sufficiently 
small they may not be cut at all.
Next, about the ingredients: fish is definitely the most common ingredient, 
but octopus is pretty well standard, as well. In addition, a variety of other 
creatures, as you mentioned, may be used, too (and all this depends on the 
region, the season, and the preferences of producers and consumers). To 
make the explanation comprehensive but not too long, it could perhaps be 
written along those lines: "slices or small pieces of raw seafood - 
predominantly fish fillet but also octopus, shrimp, shellfish, etc." :-)
What do you think? ( I  think in cases like this it is quite appropriate that the 
"dictionary" acts - in parentheses - as "encyclopedia". BTW, i think the cases 
of small whole fish being sliced can safely be left to the "etc.", since there is 
actually other vocabulary at hand for that: see, for example, 
http://en.bab.la/dictionary/english-japanese/whole-fish-sashimi :-)

i'm not sure about that, but it also applies to shellfish, etc. so "fish" isn't even 
really correct...  and you can't "fillet" a shrimp, i wouldn't think.

Aren't there some forms of sashimi using soft-boned fish where the whole fish is used in cross-cuts?