Shipwreck (Panther science fiction)

Galactic Crusoe.

When an atomic explosion destroys a huge expedition ship, Tansis becomes the sole survivor. A skilled space pilot, he manages to land his scout craft on the nearest planet. The alien world in which he finds himself is not hostile but has no means of supporting human life. Desperate for intelligent contact, Tansis establishes a telepathic relationship with the extraordinary seal-like creatures who live in the planet's oceans. But just as things seem to be going smoothly, the craft computer warns Tansis that the energy supply is running out and he is forced to take drastic measures to safeguard his own survival...