Russia celebrated its annual Black Sea Fleet Day with a notably smaller fleet in Sevastopol than just a few years ago. How has Ukraine managed to win in the sea? What has the Nato military alliance learned from that success? And how does Turkey exercise control as the gateway country to the Black Sea? We speak to Hanna Shelest in Odessa, James Bergeron of Nato Maritime Command and Turkish-American political scientist Soner Cagaptay.