Scott-Arrieta recently surfed in the ISA World Junior Surfing Games as a member of the New Zealand Junior Team, and showcased his repertoire in the clean 1.5m plus waves at Mukerau Two.
Local surfer and points leader Kalani Hansen, of Kaitaia College, also continued his solid performance this year in the series coming second behind Scott-Arrieta in the final.
Another stand-out surfer was Pompallier's Kohl Mase who has placed in two finals this year in the series alongside Boys' High's Jamahl Moselen.
Due to challenging conditions, the Under-14 Boys Division was run at Mukerau Beach and the under-14 and 16 girls at Shipwreck Bay.
The under-14 boys enjoyed perfect, long, 1m left handers breaking down the point, favouring the goofy footer in the final.
Pompallier's Luca Mase claimed his second victory of the series ahead of Bream Bay College's Tom Norton.
In the girls event, it was Emily Brunker, of Whangarei Girls' High School, claiming her first win this year ahead of good friend Billie Scott, also of Girls High, in the Under-16 Girls Division.
In the Under-14 Girls Division, it was Macy Polwart - of Girls' High - who picked off the best waves in the final to win the division comfortably.
Next up for the Northland Scholastic Surfing will be the naming of the Northland Scholastics team that will compete at the 2014 Surfing New Zealand National Scholastic Surfing Championships. The competition is being held in New Plymouth from September 29 to October 3.