Marine Matters – by Phil Coulthard – Operations Manager & Marine Biologist, Dolphin Discovery Centre
As featured in the South Western Times
The last 4 weeks have been incredible for our local dolphins with calm weather and warm water creating the perfect scenario for the tail end of their breeding season. There are still a lot of dolphins in the Bay, many of them males searching for the last of the available females to mate with before the cold weather brings to an end their season of love. Why the breeding season only occurs at this time relates to the ideal water temperature for calving, which in Bunbury appears to be between 22-24 degrees following the summer peak. The fact that female dolphins have a gestation period of exactly 12 months is also the reason why the mating and the birthing period falls around the same time of year so anyone out on the water during March and April will have an incredible opportunity to not only see lots of dolphin activity, but plenty of baby dolphins as well.
On the subject of dolphin babies, some of you may also recall my concerns about the lack of calves born this year in an earlier Marine Matters column. The good news is that there are now 5 new baby dolphins in the area and four of them are spending a lot of time near the Cut and inside the Leschenault Estuary together as an extended family group. The proud new mums are all local dolphins who we know very well and their babies at this stage appear happy and healthy. One of them in particular named Cookie has become a real crowd favourite both on the boat tours and at the Dolphin Discovery Centre beach. Cookie was born in February and was the first calf for this season so he has now learnt to swim, jump and surf alongside his mum named Cracker. Another local favourite called Nicky also gave birth on Tuesday morning, producing her first new calf since suffering a horrific shark attack back in 2007. Although she had a 2 year old calf called Rocket at the time, he disappeared shortly after the attack and was never seen again. Whether he too fell victim to a predator or simply decided to move on a let mum recover on her own is a question we will never likely be able to answer, however it does suggest she may have sacrificed his life to save her own.
On the subject of sharks, I wrote a column in February expressing our concerns for a very popular local dolphin called Mrs Iruka who also suffered a terrible shark attack recently. The injury at first appeared to be nothing more than a flesh wound, however a closer inspection using an underwater camera revealed significant deep lacerations that were a lot more severe than first thought. Unfortunately, Mrs Iruka has not been seen for over 6 weeks now suggesting that she has either moved out of the Bay or has suffered the worst case scenario and died from a secondary infection. The fact that a dolphin carcass has not been found leaves us with a little bit of hope that she is ok so we plead with all of you who will spend time out in the Bay over the Easter period to contact the Dolphin Discovery Centre if you see her. Photographs are always the best way to identify the dolphins so a quick shot of the dorsal fin is all we need. As you can see from the photograph, the markings on her dorsal fin and the shark bite injury across the top of her head should make her easy to identify so please let us know if you see her over the Easter period by calling the DDC (9791 3088) or e-mailing firstname.lastname@example.org.