I know what an elasmobranch is:
a cartilaginous fish of a group that comprises the sharks, rays, and skates. Compare with selachian .
Subclass Elasmobranchii, class Chondrichthyes.ORIGIN late 19th cent.: from modern Latin Elasmobranchii (plural), from Greek elasmos ‘beaten metal’ + brankhia ‘gills.’
It was an elasmobranch that killed the Australian naturalist last week.
I guess that to be destructuralized the fish would need to be rotten.

A rather clever diver's joke!
Andrew
ps I did toy with the idea that the destructuralization may have been due to the fish being dismembered and presented on a fishmonger's slab, but I dismissed this notion because destructuralization by decomposition was a far funnier prosepct and less prosaic than a fishmonger weilding a filleting knife.