Dry weather hampers mass Christmas Island crab migration

SYDNEY (Reuters): Unusually dry weather has delayed the annual migration of millions of Christmas Island red crabs from the island’s interior to the sea where they mate.

There are over 100 million red crabs on Christmas Island in the Indian Ocean, much of which is designated as a national park. The crabs are unique to the island and protected by Australian law.

Authorities say “exceptionally dry” conditions have put a dampener on this season’s migration, where the mass of red crabs usually blocks off traffic in a normal year.

“In the last 12 months, we got about half our average rainfall for that period of time, and that was enough to make the island look extremely desperate, dry and dusty,” said Brendan Tiernan, the threatened species field programme coordinator for Parks Australia.

“And it kept the crabs from migrating.”

This year is the first time the crabs have migrated as late as February since Parks Australia started tracking migration in the 1980s, he added.

The migration sees the crabs journey from the interior of the island to the ocean, where they mate. The females then stay behind in burrows near the ocean to hatch their eggs and the males return inland.