It seems this research is being carried out in order to eventually
allow surrogate breeding of tuna, which are now endangered by
overfishing. The idea being to implant tuna eggs in mackerel, and farm
the result. Nobody has as yet addressed the matter of what these fish
will be fed on. More massive quantities of wild marine protein in the
form of fishmeal, which is already causing severe environmental
problems.

One suggestion I heard is that dead human bodies might be used as
feed, as they do contain a lot of the required material, although
there are problems with this. Many fish can not assimilate some things
very well, or even at all.

One is also bound to wonder what PSE ( Piscine spongiform
encephalopathy) will eventually look like? Or even consider the
pleasant pastel shades of Soylent Green waiting for the remains of the
human race.

TL
MC