The cause of mass crab deaths on the north east coast may never be known, an environment minister has claimed amid calls for further investigation.Mark Spencer told MPs that scientists are "ready to jump into action at great speed" to try to establish the facts if a repeat mass die-off of marine life occurs on the coastline from Hartlepool to Whitby.

The cause of mass crab deaths on the north east coast may never be known, an environment minister has claimed amid calls for further investigation.Mark Spencer told MPs that scientists are "ready to jump into action at great speed" to try to establish the facts if a repeat mass die-off of marine life occurs on the coastline from Hartlepool to Whitby.