Doctor Andrew Brownlow, who carried out an autopsy on the whale, admitted he was not sure how the mammal came to swim up the Solway but concluded it might have simply been lost.
The juvenile male may have been following a shoal of fish or other food source and become disorientated.
The Fin Whale normally lives in the mid Atlantic.
The species spends the summer near the Arctic but comes further south in the winter.
More top news
Emma brings you Saturday's forecast for the Border region
Paralympian double gold medalist Libby Clegg says "it's not even sunk in yet" as she returns home to Newcastleton.
Police are concerned for the welfare of Ronald Benstead, a missing man from Carlisle.