Roe has several uses. It can be eaten to restore 300 life points, or used as bait to catch more fish at Barbarian Training. Lastly, it can transform 5 of the most basic types of potions into their respective Barbarian Potions.
Players either deposit the roe in the bank chest in the Barbarian Assault lobby for later use, or use the roe along with the offcuts as baits for more Barbarian fishing. Unlike most other edible foods, eating roe can only be accessed by right clicking.