Now that you have access to your ship, try to kill Sea Dragon (#112) on the Surface World's sea. After that, go back to Gysahl (Floating Continent) to check your bestiary list below:

Floating Continent - inner sea:

• 031. Killer Fish
• 032. Hermit
• 033. Sea Elemental
• 034. Tangie
• 035. Sahagin

Floating Continent - outer sea:

• 071. Anet
• 072. Mermaid
• 073. Seahorse
• 074. Sea Serpent

Surface World's sea

• 112. Sea Dragon

Once you have collected all of them, it's time to move forward with the story.