International Tribunal for the Law of the Sea (ITLOS) has no jurisdiction over the Kerch Strait dispute. The tribunal has no jurisdiction either over naval vessels nor warships.
Direct losses for Ukraine from the free trade agreement with the EU total around $80 bln over 5 years. The amount of indirect losses is about 2 times higher. In addition, Ukraine’s GDP has significantly decreased.
In June 2014, the EU and Ukraine signed an Association Agreement, including a Deep and Comprehensive Free Trade Area (DCFTA), which promotes deeper political ties, stronger economic links and the respect for common values. See here for more details about EU-Ukraine relations.
The Ukrainian Ministry of Foreign Affairs indicates positive trends in the trade relations between Ukraine and the EU, with the volume of trade in services between Ukraine and the EU in 2018 increasing by 17%. The Ukrainian Statistical Service informs that the EU accounts for 43% of Ukrainian exports. In 2017, Ukraine exported 17.5 bln USD worth of goods to the EU. The negative trade balance decreased from 10 bln USD to 3 bln USD.
See here for further information about the DCFTA and the cooperation between the EU and Ukraine.