What were the environmental effects of World War 2 on oceans and sea life?

Answer 1

A thorough answer would be difficult, but some of the effects were:

Huge quantities of oil spilled due to ships sinking.

Introduction of tons of Mercury, which was used in nearly all ammunition of the time.

In a few areas, sensitive reefs were damaged or destroyed by ship groundings, depth charges, mine sweeping, etc.

Artificial reefs were created in some areas by ships that sank, and some of these are preferred fishing spots today.

While many millions of sea creatures must have been destroyed by weapons like depth charges and mines, any estimate would be no more than a wild guess.

The war caused a need for large amounts of work to port facilities, especially in the US and Canada, which were the chief export nations. This resulted in massive dredging of harbors plus tremendous construction projects with no consideration of impact on sea life.

Answer 2

During World War 2, there was significant naval warfare which led to increased pollution from sunken ships and oil spills. Naval activities also disrupted marine ecosystems, destroying habitats and affecting marine life. Additionally, the dumping of munitions and chemical weapons has had long-lasting negative impacts on ocean health and sea life.