Mentaiko is very popular in Japan and Korea. It's basically roe from pollock, usually Alaskan pollock. Mentaiko is typically marinated with spicy seasonings.
The Mentaiko Spaghetti is a popular Japanese pasta dish. I prepared mine with butter and garlic, and topped it with nori for garnish. In keeping with the roe theme, I also garnished the dish with wasabi caviar.