Possible Clues:

• Sea of -- (Black Sea gulf)
• Sea of ___, arm of the Black Sea
• Sea fed by the Don
• Sea of ___ between Russia and Ukraine
• Sea of ___ (section of the Black Sea)
• Russia/Ukraine's Sea of ___
• Sea near Crimea
• Sea of __, shallowest in the world
• Sea of ___ (view from Crimea's eastern coast)
• Sea of ___, outlet of the Don River