Possible Clues:

• Island of Tanzania
• Large amount of water moving in
• Arrival of sudden flood at Florence, reportedly?
• Dope - taking in line, with this smooth entry?
• Tidal bore
• No escape to return the predator to Ulster
• Rate of arrival in fact halved - not high
• There's no escape from the predator that returns to Ulster
• The entry of the canine to Ulster back there
• Water's movement, at times