Operation Orca, by Ron Roy (A-Z Mysteries #7)

Thar she blows! Dink, Josh, and Ruth Rose are on an Alaskan whale watching adventure. On their first day, they see a mother orca and her calf. But the next day, the baby orca is missing! The calf needs its mother’s milk. Can the kids solve this whale of a mystery? (Some stressful parts/chapters were skipped over because my 3 year old listens to this with my 5 year old.)