High water temperature warnings have been issued for the country's western and southern bay amid the prolonged heat wave.

According to the National Institute of Fisheries Science, as of 2 p.m. Friday, the existing high water temperature advisories for Cheonsu Bay in South Chungcheong Province and Doam Bay in South Jeolla Province were raised to high water temperature warnings.

The advisories were also extended to include coasts along the central part of the Yellow Sea, the central and western parts of the southern sea, Jinhae Bay in South Gyeongsang Province and waters off Heuksan Island.

The institute said due to the ongoing heat wave, temperatures in some parts of the western and southern waters have surpassed 28 degrees Celsius.

An advisory is issued when the water temperature exceeds 28 degrees and a warning is issued when such high temperatures last at least three days.