Protesters gathered in the central square of Barbate in Cadiz to the mourn the death of the young boy, who is being described as Spain’s Alan Kurdi – the three-year-old Syrian boy whose lifeless body was pictured on Turkish shores in 2015.
The famous photo prompted outrage at the plight of refugees and was seen by millions.
The decomposed body found in Barbate on Friday is said to be of a six-year-old boy from the Democratic Republic of Congo named Samuel.
He died with his mother when their inflatable boat sank while attempting to cross the Strait of Gibraltar between Morocco and Spain.
While the number of migrants who have died off the Spanish coast is officially in the hundreds, the UN refugee agency estimates that more than 20,000 have been killed since 1988 trying to reach mainland Spain.
“We don’t know how many Alans, how many Samuels or how many men and women lie at the bottom of the sea without their families knowing anything,” said Rafael Lara of the Human Rights Association of Andalusia (APDHA) at Tuesday night’s demonstration.
More than 200 people are said to have attended.
Mr Lara said they wanted ‘to express revulsion at the deaths on our borders caused by the sectarian politics of our governments’.