Tip: When hunting the frigid currents and turbulences - turn your shaders OFF. With the shaders on these buggers will blend in to the surrounding making them really hard to spot. You will find yourself getting jumped by the aggressive turbulences more than you want and it's a looong run back from the docks if you die.
Turning the shaders off will make them visible from a lot longer distance and it will make your life a whole lot easier when you do this part of the quest.