Hi there
First: the heat will be a real shock to the family, so be prepared!
Second, Port Douglas is amazing but VERY focused on tourism. Reef tourism specifically. HIGHLY unlikely there will be a job for your wife there as there are lots of Ausi marine biologists working the tourist vessels already. Also - it's posh, so real estate will be a bit pricey.
HOWEVER - Cairns is 45 minutes away and this is a large regional hub with LOTS of opportunity for marine biologists. It's the gateway to the Great Barrier Reef.
You will find James Cook University (specialising in all things reef) In Townsville. I suggest your wife contacts a professor at the uni to start networking.
Mackay is amazing and close to the Whitsundays, It's a bigger commercial hub but very focused on mining. That said, Mackay City Council or Port of Mackay may have a need for a marine biologist. There is lots of mining activity west of Mackay, so finding a home can be costly and difficult esp if you intend to rent!
Townsville is also where Reef HQ is located and I think there is also CSIRO activity there too (scientists). However - the gvt has just slashed science budgets and lots of CSIRO people are losing their jobs.
Inland is NOT a wise option - esp with kids and a water loving wife. It's hot, dusty and dry. Also - there's no work! Forget it!!!
Also suggest you consider Arlie Beach as this is the main town for the Whitsundays.
I'm an environmental scientist and writer and I live on the Gold Coast. Science jobs are blooming hard to come by, and as her expertise will not be on our marine environment, it will be even harder for her.
My ex husband is a marine scientist. His experience from Egypt and the USA, even though he's from Liverpool. he ended up working for SMEC (Snowy Mountains Engineering); a consulting company....but not in marine as there's no work in that field.
My girlfriend is one of the world's leading turtle experts. She's Dutch and migrated here 3 years ago. Only last month she managed to get a job working for Griffith University in the Gold Coast doing education on marine environments for schools.
Suggest you start looking at Seek.com.au and apply for anything you can; saying you're already here.
If you want to ask any other questions, please feel free to email me.
Kind regards
Chantal