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Moreton Bay landscape formation

The last Ice Age occurred predominately 8000 to 12 000 years ago. 

The areas we refer to as South East Queensland (SEQ) and nearby Moreton Bay were described during the Ice age period as Moreton Valley. About 6000 years ago, after the sea levels rose, river deltas changed and islands formed, Moreton Valley began to resemble a low lying terrestrial area with a nearby embayment. 

Today, SEQ and Moreton Bay are aligned together by two geographical features. 

The arc to the south, west and north encompasses a near continuous line of mountains ranges south from the Gold Coast hinterland of the Queensland-New South Wales border. These mountain ranges continue west to Toowoomba and finally north to the Noosa hinterland on the Sunshine Coast. The majority of rainwater in SEQ flows east from the mountains along the rivers and creeks into Moreton Bay. 

The eastern arc of SEQ features four large sand islands - Bribie Island (to the north-east), Moreton Island and North Stradbroke Island (to the east) and South Stradbroke (to the south). Bribie, Moreton and North Stradbroke Islands are three of ten largest sand islands on Earth, so these islands are important natural barriers to the open ocean and unique habitats for coast and marine wildlife species.

The water currents in Moreton Bay move in a clockwise direction. These waters are generally shallow being about 20 metres in depth in the centre of the Bay. The water is very warm in summer (32 degrees centigrade (C)) and very cool in winter (15 degrees C), in comparison to the average air temperature along coastline (25 degrees C in summer and 16 degrees C in winter).  The tide changes twice a day, with an average change of 2 metres per tidal event. 

In the north, Bribie Island lies close to the coastline in a virtually north-south alignment. Conversely, the area between Bribie and Moreton is fairly unprotected with periodic wild seas. The central bay is a place of generally smooth but windy open waters, stretching 25 kilometres east-west from Brisbane to Moreton Island and 40 km north-south from Bribie Island to Peel Island. 

The southern bay includes numerous smaller islands which have formed between the coastline and North Stradbroke Island. Although the waters in the southern Moreton Bay are the most protected, the narrow spaces, circulating current and tidal changes combine to move the sand bars continuously throughout the year.

Settlement and population growth

There is empirical evidence that Aboriginal Australians have resided within the Moreton Bay catchment for at least last two Ice Ages periods - that is for more than 31 000 years.  The Quandamooka people are the traditional owners of the islands and sea estates within Moreton Bay. They have continued their association with their country since European settlement commenced in 1824 (nearly two hundred years ago).

Captain Cook has been recognised as the first European to lead an expedition and visit Moreton Bay. He did so with the crew of two vessels in 1770. Ten years ago, in 2000, there were 48 000 registered vessels, while today more than100 000 vessels are permitted to sail and/or cruise the waters of Moreton Bay.

Moreton Bay is the basin for South East Queensland (SEQ), and demographically the third largest populated catchment area in Australia. Only Sydney Harbour and Port Philip Bay in Melbourne have higher populated catchments areas. In 1997, the population of SEQ and population were comparable in area; that is, 2.2 million people shared the 2.2 million hectares (or about five percent of the State of Queensland). 

The Queensland Government declared Moreton Bay a Marine Park in 1997. At the time, six Marine National Parks were created, however they made up less than only 0.5% (1600 hectares) of Moreton Bay Marine Park. 

Ten years later, the Marine Park has been reviewed and the population has increased to 2.8 million. Excellent leadership by the conservation sector and support from the wider community resulted in an increase of Marine National Parks from 0.5% to 16% of Moreton Bay Marine Park; that is, nearly 58 000 hectares of wildlife habitat are now protected – an increase of over 56 000 hectares.

The SEQ Regional Plan 2009-2031, forecasts for a population increase to 4.4 million by 2031. No doubt, people will inform the Queensland Government during future 10 year reviews, of Moreton Bay Marine Park, it is an important wildlife habitats will need further protection if it is to accommodate a doubling of the SEQ population in a little over 30 years.