Here is the full list of all 23 Sea of Solitude trophies - there are 6 bronze, 9 silver, 7 gold and 1 platinum.
You have collected all of the other trophies.
Swam a very long distance
Shooed all Seagulls
Collected all bottles
Swam long distance while whale was around
Respawned on couch in Skyscraper
Jumped headfirst into the water from a high point
Got grabbed by waterhands 10 times
Finished the game
Finished Level 3
Finished Level 2
Reached top of the Skyscraper
Eaten by Whale 20 times
Travelled a long distance by boat
Finished Level 1
Travelled very far by foot
Made it through school
Opened a path through water
Shooed your first Seagull
Fired 30 flares
Collected your first Message in a bottle
Connect with mirror Kay for the first time
Fired the first flare