maybe I can help u.
it depends where are u staying in Mauritius. If u stay close to Grand Baie, i know somebody who does nice fishing trips and boat trips to the islands . U can book the fishing boat for around 10000 rupees, around 230,00 € for a whole day. But u can book also a half day fishing trip. I stay myself from the 26.06 till the 30.07 close to Troux aux biches. If u want further informations u can call 7892052 (Ludovic) in Mauritius and ask for me, Claudia. Or u can call my mobile 01774881650. Maybe we can arrange something for u.