^8:9 and a third of the creatures, which were in the sea and had life, died; and a third of the ships were destroyed.

This is a continuation of the previous verse or the SECOND trumpet.

and a THIRD of the CREATURES, which were in the sea and had life, DIED;

This may be a partial fulfillment of the prophesies in Hosea 4:1-3 and Zephaniah 1:2-6. It is partial in that only a THIRD are removed with this trumpet. How this will be done is a mystery. However, once it will be accomplished, the stench will be noticeable on the earth. Furthermore, we know so little about the inhabitants of the sea, how will we know that a THIRD of them died. We just have to take God at His Word.

A symbolic view would be that a THIRD of the "sea" of unbelievers would die. This is plausible given that the FIRST trumpet destroyed so much in the way of trees and green grass (grains or sustenance). When this happens, the shocker here will be how many religious people (aka church goers) die.

and a THIRD of the ships were destroyed.

The literal view says a meteorite impact would toss ships to and fro, and obviously sinking some. Furthermore, the tidal wave would create much damage to ships in port.

An alternative view given by Ben Davidson, Space Weather News, that a micronova of the sun probably will fracture the earth's crust and along with the movement of the magnetic poles would cause the earth to flip. The shear weight of the polar ice caps would like to be at the new rotational equator. The movement of these caps would create huge tsumani waves which would carry ships over mountain ridges. Certainly, this would destroy these ships. Mr. Davidson is saying with the earth's magnetic field continuing to decline at an accelerating pace, this event could happen anytime in the next two decades.

The symbolic view is that the ships are representative of vessels of war and commerce. This implies that a THIRD of businesses would fail because of economic depression, and hence the business community is slowly destroyed. A world in depression really does not have a need for war ships. "The ships of Tarshish" and the "beautiful craft" are equated with human pride. They are prophesied to "be humbled" in Isaiah 2:12-22.