Juvenile dolphins, who have left their mothers but are not yet sexually mature, are often found to spend considerable time in large groups engaging in social play to cultivate relationships.
In Mandurah, the juveniles are often observed together in the Harvey Estuary.
Here I would like to introduce you to one of the resident juveniles, Kristen, a male dolphin who is approximately five years old.
Since we started our research we have seen him 23 times throughout the Harvey Estuary.
Only once last year, in July, we saw him in the Peel Inlet feeding with a few other juveniles and mother-and-calf pairs.
On average Kristen is seen in groups of about 15 individuals with the smallest group we have seen him consisting of four, and the largest of 30 individuals.
In January 2017, being a relatively typical Mandurah dolphin, Kristen was caught in a pool surrounded by sandbars right at the bottom of the Harvey estuary at Herron Point.
As we have discovered, a majority of the dolphins who strand in the Peel-Harvey are healthy individuals that have navigated to the shallows, usually during extreme tides, and have gotten caught. Kristen was no exception.
Since he was helped to deeper water, we have observed him back with his usual associates frolicking in the Harvey estuary.
On July 8, however, we observed Kristen with at least 22 other estuary residents – none of whom we typically see him with and none of whom we have never seen in coastal waters – exit the Mandurah channel into Comet Bay and continue west into the sunset.
Six days later he was back in the estuary with his buddies.
I was surprised to see him venture into the ocean, but at the same time excited to discover more about him and how he, and the other juveniles, are integrating into the dolphin society.
The MDRP is a partnership between Murdoch University, City of Mandurah and Mandurah Cruises that commenced in January 2016.
They are measuring how many dolphins use the Peel-Harvey waterways and how they are connected to dolphins in nearby coastal waters.