Short story about a multi-species team which is composed of humans and some other alien species sent to study an amphibian sentient species which suffers a pandemic that damages their gills. Aliens in the human team are telepathic.
The first few paragraphs of the story refer to the gill disease issue:
It was past midnight at the GalFed Observer station on Xirifor II; mist swirled over the waters, and the huge float, which housed all Galactic Federation business on the planet, was tugging gently at its moorings. Ripples moved in silence against the timbers under the cool night winds. Inside, in the tank room, a hand turned up the cock on Vavvingru's sleeping tank and he quietly began to drown.
Water poured between the flared leaves of his lungbook, but he did not waken; although he had lost his external gills from disease, what was left of his internal system extracted the mixture of available gases he called air for half an hour; then it became overloaded, and he started choking.
Telepathy is mentioned in a passage soon afterward:
Across the room, in a larger tank full of the waters of a different planet, Hrufa stirred in her sleep and woke. Without having to open her eyes, she knew everything in less than a second...
She began to broadcast powerful impulses, soundless wordless siren blasts. If they had been audible, they would have shattered eardrums and perhaps skulls...
... the tp waves knocked the Solthrees out of their bunks...
I did also find an excerpt from a discussion about it via Google Books:
It is better to believe, and probably the truth, that GalFed would have come to the aid of the Xirifri even if the survey ship had not discovered that the seas of Xirifor produced oysters that secreted pearls, huge, baroque and blue, more beautiful than any known before. Whatever the truth was, the pearls at least gave the peoples of the planet something to bargain with.
Hopefully, those names sound familiar.