Contrary to the statement of the person who considers performing ablution and bathing with sea water to be disliked, his claim is that there is fire beneath the sea, and beneath the fire is the sea, in this way there are seven seas and seven fires. Due to this alleged reason, he considers performing ablution and bathing with sea water to be disliked.
Sayyiduna Abu Hurairah narrates that a man asked the Messenger of Allah (peace be upon him) a question, saying: "O Messenger of Allah, we travel by sea and take only a little water with us. If we use it for ablution, we will remain thirsty, so can we perform ablution with sea water?" The Prophet (peace be upon him) replied: "Its water is pure, its dead (animals) are lawful." This is the hadith of Yunus. The Imam says that Yahya bin Hakeem, in his narration, has mentioned « عن » Safwan bin Salim instead of « حدث ». He did not mention « من اٰل ان الأزرق » with the name of Saeed bin Salamah and did not mention « من بني عبدالدار » with the name of Mughira (i.e., he did not mention their tribes). He also added these words: "We remain at sea for long periods."
Hadith Referenceصحيح ابن خزيمه / جماع أبواب ذكر الماء الذي لا ينجس، والذي ينجس إذا خالطته نجاسة / 111