Unless I am mistaken, looks like your circle encompasses most of modern day French Polynesia, a territory of France which comprises 5 different archipelagos, some 120 islands, and covers an area comparable to Europe.

I’m not really sure how to answer your question aside from asking one of my own, what do you want to know? I have book shelves of volumes on the region; Douglas Oliver has three volumes alone on history and society in Tahiti from the beginning of time till ~1810 which can be found freely available from ANU’s ePress (Australia national Univeristy.)

As much as it pains me as it’s quality is so uneven in this area, you may want to start with a stroll through Wikipedia or another encyclopedia if you just want a general feel for the area.

You may want to consider posting a more specific question as a new thread if anything strikes you.