Humpbacks working on shifts?

During the weekend, we saw the humpback whales again on all 4 tours:  
On both trips on Saturday as well as on both trips on Sunday we saw one humpback whale per trip.
All sightings occurred in the same area, but there was something really strange about it:
It might have also been just a coincidence, but the humpbacks seemed to have certain “shifts” during the weekend:
There was one humpback that we saw only on both of the morning trips
(10:00) on Saturday and Sunday, whereas the other humpback was only seen during the afternoon trips (13:30) on Saturday and Sunday.

It is possible to identify humpback whales individually by comparing pictures of their flukes.
Before going down for a dive, they often lift their fluke and on the underside of the fluke, each humpback whale has a very distinctive black and white pattern. It is like a human fingerprint, there are no two humpback whales that have exactly the same black and white pattern on their fluke.
If you take a good look at the following pictures, you will be able to see that it were in fact two different humpback whales that we saw during the weekend.

This humpback whale was seen during both morning trips (on Saturday and Sunday)….

….and this humpback whale was seen during both afternoon trips. It is the same whale that has been seen on many trips since last Saturday, so he (or she?) has been in the area for more than a week now.

Christian, guide