Taizee is going to be afraid of the dark. Which is along with her hunger and very active metabolism (compared to her more slow going kin of the deep) the reason why she ventured towards the light. There is a faaair amount more food to find higher up in the water, and following that logic, together with the desire to discover, both places and people (in both aspects), is how she decided to go up on land to and explore the world she previously could only see from the surface and hear from the sailors and harbourworkers.