A bit down the board RST posed a question about Thai crab roe paste, which is included in the list of ingredients for a recipe in the David Thompson book. RST, is it the Crab Roe Relish, nam phrik kai bpuu?
I have never seen canned or bottled crab roe paste in Bangkok, though that doesn't mean it doesn't exist. Though lobster tomalley *is* available fresh in the market if you inquire with a lobster seller. When I'm stumped, my primary source of information on all things Thai culinary is our maid Wan, a truly adventurous chowhound and homestyle cook not to be equalled anywhere, I think. She's also from Issaan. Wan claims not to know of canned or jarred crab roe in Thailand, and says that it is rarely sold at market because it's such a tiny amount per crab (unlike tomalley, a lot for the same amount of effort). People wanting to make naam phrik like that described in Thompson's book just buy their own (female) crabs and use the roe byproduct, after steaming, to make the relish.
I would think since it has garlic and possibly fish sauce added, that the taba ng tlangka would not be a reasonable substitute. Maybe in a pinch. But I think you'd have to make the fresh roe relish first to know what sort of taste you are shooting for.
According to Wan, tomalley naamphrik is soooo much tastier than the crab roe stuff. I'm gonna have to try some.