A glimpse of life under the bay
As backyards go, the waters of Byron Bay, particularly around Julian Rocks Marine Park, are unique, brimming with marine life such as dolphins, turtles, rays and of course, the majestic humpback whales who have just finished passing our shores on their annual migration.
Humpbacks are some of the largest animals in the ocean. At 15m long they are longer than most boats that frequent the bay, and at 40 tonnes are certainly heavier than all but the larger vessels.
Each year the majority of the 11,000 strong population will make the long swim north from Antarctica to the warmer waters of northern Queensland and beyond to provide pregnant females the most favourable ocean conditions to give birth.
During their migration humpbacks generally travel in waves of like kind: males, juvenile males and females, pregnant females and the last to pass through the bay are the mothers with their newborn calves. It is this group that is responsible for most of the surface activity so eagerly awaited for by whale watchers.
Surface activity is associated with communication and we certainly see this from the mother, letting other whales know to steer clear of her calf. The calves, on the other hand, behave like a child with a new toy and practice their newly learned moves, breaching or tail slapping over and over again not so much to communicate but to finely tune the skills that will become so important to them later on in their adult life.
They are amazingly precise with their aerial acrobatics and seem to know exactly how close to the boat they are. One adult whale tested his skills to the extreme during the migration, making many of us hold our breath as it breached not 5m from the front of the boat, wetting those of us located on the bow.
Whales don’t communicate solely through breaches and tail slaps – however, they are also renowned for their song, which is actually projected from their blowhole. The hauntingly beautiful song can be heard underwater whilst diving or snorkelling and on board a boat using a hydrophone.
It can be a very loud experience underwater having a whale sing nearby, and even on board a vessel. Those on board were lucky enough to have a very special and memorable experience when out on the water one day – while sitting near the Brunswick bar scanning for pods of whales, there was an eerie sound on the boat, a haunting, whistling and groaning.
Having checked for loose fittings that might have been blowing around in the wind, we soon managed to make sense of what we were hearing. A whale had positioned itself under the boat and was singing at the top of his lungs to whoever was listening.
This song was resonating through the hull of the boat, enabling us to hear him and even feel the song travelling up through our feet. It was a unique and very moving experience.
As the years go by the migration season extends and we see more and more whales travelling past our shores earlier and later than the year before. The whale season has finally come to a close now and the numbers have dropped off, leaving the bay waters to return to something a little calmer and less resembling a circus performance act.
As the whales depart and summer arrives, we welcome into the bay other amazing marine life such as manta rays, leopard sharks and several species of turtles.
Our remotely operated vehicle (ROV), an underwater robotic camera, is now being put to good use as we cruise around Julian Rocks.