Possible Clues:

• Waterborne creatures arrange untied knot
• Piece of wood: heavy weight that floats in the sea
• Small organisms, hundred on piece of wood
• Drifters not mountain climbing around North Korea's capital
• Idiot has not served up seafood
• Microscopic organisms in great number on board
• Sea creatures not turning up under part of ship
• Fish food
• Small sea organisms in large quantity on board
• Floating whale food