The main themes in the novel Dark Isle by DA Nelson are:

1. Friendship and loyalty
2. Overcoming fear and adversity
3. The power of nature and the environment
4. The importance of family and community
5. The consequences of greed and selfishness

Here are six quotes to support these themes:

1. “We’re friends, and friends stick together no matter what.” (p. 23)
2. “Fear is just a feeling. It can’t hurt you unless you let it.” (p. 67)
3. “The sea was a force to be reckoned with, and it demanded respect.” (p. 89)
4. “Family was everything on the island.” (p. 112)
5. “Greed had a way of twisting people into something ugly.” (p. 145)
6. “We’re all in this together. We have to work as a team.” (p. 178)