Follow the waterfall from the snow cave by Viking bay it should have a waterfall from inside the cave coming out and just follow that all the way down to where the waterfall has a entered pools of water there are around 2-3 pools of water check them one of those shoiuld have a pair of otters, if you wait you will start to see more show up as their population has barely started , unless people in your server take them then they will stay rare