After heavy rain, nutrients flow into harbour waters. This attracts fish that dolphins and sharks like to eat. Therefore, it is not a good idea to swim in public waters within 72 hours after a storm.

Assuming that such urgent swimming is, for some reason, very necessary, there are superordinate principles.

Humans have safety in numbers, because crowds make too much noise for sharks.

If a shark is encountered, look it in the eye. Maybe punch it in the nose, but that is out of the scope of this article.

References

1. Pepin-Neff, C. (2026). Shark warning: after heavy rain it’s not safe to go in the water. [online] The University of Sydney. Available at: https://www.sydney.edu.au/news-opinion/news/2026/02/05/shark-warning-after-heavy-rain-its-not-safe-to-go-in-the-water.html [Accessed 14 Feb. 2026].