Poisonous sea snakes are found in the Pacific. They haven't made their way to the Atlantic. Yet. (this was one of the hazards discussed when a sea level Canal

Poisonous sea snakes are found in the Pacific. They haven't made their way to the Atlantic. Yet. (this was one of the hazards discussed when a sea level Canal was studied, once upon a time. Construction on a third set of locks began in WWII when there was an entire Division in Panama to defend the Canal and the soldiers had free time on their hands. The effort ended with the war. New discussions revisited the idea in the early 1960's when we were still in the "our friend the atom" days. The idea of nuclear explosives was suggested. Among the many reasons for discarding the project was the threat that highly venomous Pacific sea snakes would cross the new sea level canal and enter the Atlantic.)