Natural science today

After maths Daniel learned about the following sea creatures:
http://de.wikipedia.org/wiki/Walhai (Whaleshark)
http://de.wikipedia.org/wiki/Mantarochen (Mantaray)
http://de.wikipedia.org/wiki/Blaupunktrochen (Bluedot Stingray

These stingrays get sold at the market like fresh sliced bread,maybe nice to know some more about them.:)