I kind of figured as much. Interestingly, with EMF it probably should be the other way around since there are a number of marine animals that use electric fields to survive. But according to this 2009 report, the impacts of underwater cables are still unknown:

Therefore at this point it is known that the sub-sea cable emissions can be detected by the sensory organs of several marine organisms although very little can be predicted about what kind of interaction this may trigger. It is very hard, with current data, to estimate if there can be a species or an ecological impact from EMF.