The BDMLR said it was not the same pod of whales which was herded out of the River Thames at the weekend as the distance between the locations was further than the species could swim in 24 hours.
Local boats were launched with medics on board to try to herd the whales offshore to stop them from stranding.
But the animals remained tightly packed around one of the largest, which was lying motionless on its side.
The teams were stood down after losing the light on Sunday.
Earlier on Monday, the BDMLR said about a dozen had been stranded on Coquet Island around rocky terrain.
On investigation, six animals were found – five ashore and one afloat.
Two of the stranded whales were confirmed to have died, the BDMLR said.
Due to the tides and limited access to the island, attempts to refloat the live animals were not possible and the teams withdrew once again.
The BDMLR said it would remain along the coast, ready to provide care and attempt to refloat those which were healthy enough.
The RSPB said its staff from nearby Coquet Island were continuing to support the BDMLR’s response to the incident.
“This is a distressing situation and our thoughts are with all those involved in the response,” a spokesperson said.
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