The Uplift Saga #2: Startide Rising by David Brin

The Terran exploration vessel Streaker, crewed by 150 uplifted dolphins, 7 humans, and one uplifted chimpazee, discovers a derelict fleet of spaceships — each the size of a small moon. They appear to belong to the Progenitors, the fabled First Race who seeded wisdom throughout the stars.
Bearing one of the most important discoveries in galactic history, Streaker crashes on the uncharted world of Kithrup. Above, in space, armadas of alien races desperate to possess the knowledge of the Progenitors clash in a titanic struggle to claim the right to capture the prize. Below, Streaker’s crew battles armed rebellion and a hostile planet to safeguard her secret — the fate of the Progenitors.

The second book in the Uplift series, Startide Rising (The Uplift Saga, Book 2), was WINNER: 1983 Nebula, Hugo, and LOCUS Awards for Best Novel.