Could you please explain the rationale and reason for prohibiting crab meat, lobster, and scaleless fish?
Islamic rulings are derived from the Holy Quran and the sunnah of the Prophet (pbuh&hp) and his purified progeny (pbut), and we are obliged to abide by them whether there is an explanation of the law or not. Moreover, we cannot guess why something is unlawful, we must refer to the source of legislation to see if an explanation is provided. In this case there are no such reports.