Which claim is stronger?

Sea turtles are most important to the health of coral reefs.
I think that sea turtles are the most fascinating animals.
Many interesting types of sea turtles live in the ocean.
Only sea turtles can excite children and adults alike.

The claim "Sea turtles are most important to the health of coral reefs" is stronger. This claim is more specific and has a clear impact on the ecosystem. The other claims are more subjective and do not have a significant impact on the environment or other organisms.