What happened to the Sjandra Kei Commercial Security Fleet after its encounter with the Blight? Does the book ever specify how many Sjandra Kei ships survived?
The Sjandra Kei Commercial Security Fleet renamed itself the Aniara Fleet after the battle with the Blighter fleet. One hundred Sjandra Kei ships survived:
"There is no Commercial Security anymore. Virtually all our customers got shot out from under us. Now we've killed our company's owner -- or at least destroyed her ship and those supporting her. We are Aniara Fleet now." It was the official name chosen at the fleet conference just ended. There was a certain grim pleasure in embracing it, the ghost from before Sjandra Kei and before Nyjora, from the earliest times of the human race. For they were truly cast away now, from their worlds and their customers and their former leaders. One hundred ships bound for....
"We talked it over. A few still wanted to follow you to Tines' world. Some of the crews want to return to Middle Beyond, spend the rest of their lives killing Butterflies. The majority want to start the races of Sjandra Kei over again, some place where we won't be noticed, some place where no one cares if we live." And the one thing everyone agreed on was that Aniara must be split no further, must make no further sacrifices outside of itself. Once that was clear, it was easy to decide what to do. In the wake of the Great Surge, this part of the Bottom was an incredible froth of Slowness and Beyond. It would be centuries before the zonographic vessels from above had reasonable maps of the new interface. Hidden away in the folds and interstices were worlds fresh from the Slowness, worlds where Sjandra Kei could be born again.