Trouble with pearls

First of all im sorry if this is wrong sub forum because my question is about MHFU, not MH2G. Also, my english is very bad, hope its still readable.

So, there is trouble with rare (G rank) resource.
Name of item - Giant Blk Pearl (Black i think =) )
Only way to get them which i know is to wait while G rank daimyo or shogun
will finish eating, but there is small chance for Giant pearl.

I wouldnt ask where to get whem if there wasnt 3 of this pearls in my box!
There are they from? Im sure that I wasnt waiting while lobsters finish there
dinner also I wasnt able to crack G rank shogun shell.
So there is other way to get them?

Those 3 pearls are now consumed, I need 2 more.
Wasting time while monster is eating is a bit time wasting because
killing him (if he didnt drop pearl) is a bit hard (it takes 40-49min, maybe because i have old weapon from previous rank).

Im exactly on G:

Just killed daymio hermitaur on G* and carved needable pearl.
And wow, with new weapon it was about 16 mins to kill it without any traps.