Manta-Ray Mating Season?

This morning I took my nephew Pila visiting from O'ahu out for a paddle on my pair of one-man/one-woman canoes. We launched from Kama'ole I Beach Park, Kihei. We surfed the bumps outside The Cove Beach Park for a bit and then paddled down to the Mana Kai. He was especially excited by the Manta-Rays that we came upon about a half a mile out from the beach. Over the years, my eyes have learned to recognize their fins flapping on the surface. I love how graceful they are in the water... sort of like birds soaring undersea. There were four Rays swimming together and circling. I wonder, is it Manta mating season? It turns out that there is no specific mating season for Manta-Rays.