Here are a few games for you, they all have a bit of a Marine Biology theme to them.

Dodge Fishy - Mind you don't get eaten!

Octopus Pong - Like regular pong but with more arms.

Ice Slide - How far can you make your character slide?

Seascape - Explore the ocean bottom as a SCUBA diver

Printable Word Searches -

                        Easy - to get you started

                                  Medium - to make you think

                                  Hard - to test your knowledge