1.6 Update It is now possible to obtain Squid and Midnight Squid Roe in normal gameplay

[Junk]

After reading the "Jewels of the Sea" book, you can obtain roe from squids by nabbing a treasure chest while catching a squid.

Pre 1.6 squid roe wasn't really attainable because squids produce ink instead of roe when put in a fish pond.
Squid Roe is worth 70g and Midnight Squid Roe is worth 80g. Not really worth selling but could be shown off to your friends as an oddity.

I just posted this cause I thought is was interesting and should be added to the wiki.

 

[FilthyGorilla]

You can also get roe from the legend fish and legend 2 fish. Either with treasure chests or turning them into bait.