According to Otero, 7,900 people arrived in Andalusia in the first seven months of the year, nearly triple the number of arrivals in the same period in 2016.
The next day, about 700 other migrants from Africa tried unsuccessfully to storm the border crossing between Morocco and Ceuta, a tiny Spanish enclave on Africa's northwest tip.
Sunbathers on a southern Spanish beach were startled this week when 30 to 40 fully clothed men pulled up to shore in a rubber boat and scattered across the sand. Overall numbers have fallen by nearly 60 per cent from the same period the previous year.
The arrivals to Greece decreased to 12,191 this year, when compared to 161,232 last year, the IOM said.
The migrant crisis is far from over, and this video is a glaring reminder.
Spain and Morocco on Wednesday agreed to close the Tarajal post to freight traffic for a week because of recent migrant crossing attempts.
On Thursday morning, Spanish coastguards said they had rescued 10 men from sub-Saharan Africa in a rickety boat off Tarifa in southern Spain.
This is a different tactic to many migrants arriving from Libya, who are often packed onto leaky, overloaded boats, with the intention of summoning aid as quickly as possible.
While the figure pales in comparison with arrivals in Italy - where more than 96,400 have landed so far this year - Spain is catching up with Greece where 11,713 have arrived by sea in the same timeframe.
"Otero noted that Spain was capable of welcoming more refugees, adding that it could offer legal alternative ways to reach the country, such as humanitarian or student visas, adding that Spain was a somewhat safer route than those into Italy or Greece".