Korean immigrants introduced now-familiar "Korean-style carrots" (morkovcha), spicy marinated young fern shoots, and pickled burdock. Why? Because the island lacked their beloved napa cabbage for kimchi, so they adapted their signature pickling methods to locally available plants.
Interestingly, I only learned that fern is actually eaten in the Russian Far East a few years ago. Yet for Sakhalin residents, it's everyday food. It's harvested in spring when the young shoots first emerge, tender and flavorful. Three varieties are prized: the most famous and popular is bracken (orlyak), while osmunda and ostrich fern (fiddleheads) are used slightly less often.
Fern is first soaked for a long time, then boiled, and finally stewed with fried onions, red pepper, and soy sauce. Garlic and roasted sesame seeds are added at the end.