A.T. Robertson Commentary Revelation 8:9

"and there died the third part of the creatures which were in the sea, [even] they that had life; and the third part of the ships was destroyed." — Revelation 8:9 (ASV)

Of the creatures (των κτισματων). See 5:13 for this word κτισμα. Even they that had life (τα εχοντα ψυχας). Here the nominative articular participle is in apposition with the genitive κτισματων, as often in this book. See Ex 7:20 for the destruction of fish, and Zep 1:3.

Was destroyed (διεφθαρησαν). Second aorist passive indicative of διαφθειρω, old compound, to corrupt, to consume, to destroy (perfective use of δια), also 11:18. The plural πλοιον just before the verb makes the idea plural.