I would say none of the options. This evidence does not support the hypothesis, but it doesn't contradict it, however it is related to the hypothesis. I guess what I'm trying to say is that the evidence isn't sufficient enough to make any definitive comments about the hypothesis. I don't think that you can just decide on whether to accept or reject your hypothesis based on observation alone and moreover, an observation that was made once. You need to make many observations, at certain points every day, in the same area of reef and the same area of open sea for a certain amount of time to gain a good amount of data (you could split up areas of reef and open sea on a particular coast into square meters or what ever unit you want and dedicate 3 days to each area you've split up) then you can perform a statistical test that suits the model of your data. I hope this helps in some way and I'm sorry it's so long. I couldn't think of a shorter way to say this.
