Alga Bloom Break Out
  |  First Published: December 2007

It would be safe to say that any catches of fish on the Noosa North Shore of late have been very few and far between. Not that a fishless surf is an unusual event around here with beach seine netting being such a large problem from May to August and catches near non existent during that period.

But incredibly, the excellent August rains that most anglers rejoiced under and which initially enhanced angling opportunities, have caused an algal bloom that is now making it a virtually impossibility to find fish of any variety in the surf along the entire Teewah Beach.

Since 2001, various algal blooms have been significant in their impact along this beach and on both the eastern and western sides of Fraser Island. Hincksia Sordida in particular has received a lot of attention due to the weed like nature of the algae and the negative affect that it has had on tourism in the Noosa region and its near permanency on the eastern beaches of Fraser Island for the past six years. However in this instance, the algae that is causing the surf here to be a perennial brown is thought to be the same as the one nominated recently in the Courier Mail affecting Moreton and Deception Bays.

Lingbya Majuscula has been well documented around the world as being a 'toxic algal bloom' with potential 'harmful' affects to humans and devastating affects on the marine environment. At this stage, I can't be absolutely certain the algae that I've been monitoring for the last 3 months here, is indeed Lingbya, which is the reported algae in Moreton Bay, as test results of sampling are still a few days away. My belief is that it will be determined to be another algae that is not plant like and can only be seen under a microscope. However, it doesn't really matter what the algae is, the results and causes are in effect the same anyway.

Amazingly this algae has caused the surf to be a distinct brown colour, or at best a stagnant green for months now and yet not many people seem to notice. In fact, the Noosa Shire Council was not aware of the fact that hundreds of kilometres off our coastline are being affected until I contacted them yesterday. Even many Teewah locals have thought that it was coral spawn or the remnant 'fresh' from the August floods. Main Beach Noosa has people swimming in perfect oblivion in this algae every day which must be of concern to the health of some individuals who may react to the toxic nature of the algae. Highlighting, that as a community, we are largely ignorant of the existence of algal blooms, not to mention the threat that these blooms pose to mankind as population growth and global warming begin to severely impact on the planet.

I read recently in the paper our Environmental Protection Agency is preparing a 'contingency plan' to deal with the Moreton Bay outbreak of Lingbya, which I find remarkable in itself. This algae is very well known to EPA and the Healthy Waterways Plan of 2003 and 2007-2012 outline quite explicitly what is required to reduce the incidence and severity of coastal algal blooms. The fact that “large rafts” of the weed have washed ashore, indicates to me the algae bloomed in Moreton Bay some time ago during a warm northerly air flow, as it did here on the north coast. Similarly, as it did here, the algae is actually dying and yet the EPA are still only 'preparing'. And given that I have recently been informed that scientists in the field can now predetermine the onset of a Lingbya bloom, I must seriously question our governments' desire to tackle this potentially catastrophic problem and their public stance on how they are addressing the issue.

To be fair, once the bloom has occurred, there is simply nothing that EPA can do to stop it. EPA has estimated that Lingbya is growing at a rate 100m square per hour in Moreton Bay. I personally believe that growth rates can be far in excess of that depending on the algae and the weather and ocean conditions. A cool weather change is the only thing that alters the optimum conditions for algal growth. The algae dies off with cool southerly wind changes and reduced sunlight for photosynthesis to occur which is when some varieties become toxic and can deoxygenate the water that it is suspended in. Apart from the bycatch of close in trawlers that has been washing in to shore in ridiculous quantities in recent weeks along Teewah Beach, has also been many dead bream, whiting and tarwhine that have suffocated in the oxygen deprived surf. Again this is no mystery, as we know that dying algal blooms become toxic and harmful to all marine life, plants and land animals and deoxygenate the water.

Exacerbating the situation is the overfishing of species that traditionally feed on these algaes causing an imbalance in ecosystems. Chesapeake Bay in the USA was once famous for their abundance of oysters. The oyster, which is a natural predator to the algaes, has substantially reduced in numbers and the area is now declared a 'dead zone'. Many scientists believe that blooms and the decimation of the algae consuming oysters have caused this. It was brought to my attention yesterday that over extraction of sea sponges near Tin Can Bay is thought to have contributed to algal blooms in that region. And it stands to reason that once an imbalance in an ecosystem occurs, that certain species will prosper at the expense of other species.

But of all the factors that cause coastal algal blooms, nutrient outfalls into our estuaries are the most significant factor. Fertilisers from cane farming in particular, but also land clearing, forestry, iron from bore water, sewage, household detergents and so on. These nutrients lay dormant until a rainfall event causes it to run off into the estuaries and then, in the case of the Noosa River, into Laguna Bay. Our August floods that we saw as a 'blessing' have actually caused this latest algal event by flushing the accumulated nutrients into Laguna Bay where the algae live.

The Healthy Waterways Strategy of 2003 and 2007-2012 addresses the nutrient outfall issue and I am thrilled that the Noosa Shire Council are now monitoring nutrient levels in the catchment region. My concern however is that nutrient levels must need reducing if blooms of the nature that we are currently experiencing are occurring and the Noosa River still receives an 'A' rating under the Healthy Waterways Scheme. I wonder how it would compare now with 50 years ago and whether the statistics are somewhat exaggerated due to a lack of a 'control'.

The Noosa River and the Mary River are two entirely different entities when discussing algal blooms. The Noosa nutrient outfalls are derived mainly from development and domestic and industrial activities, whereas nutrient outfalls from the Mary stem almost exclusively from primary industry such as sugar cane plantations and forestry. With the hincksia seemingly having its origin somewhere near Sandy Cape, the consensus is the Mary and other nearby estuaries are responsible for carrying sea grass destroying and algae enriching chemicals into Hervey Bay. All it takes then is for warm, calm conditions to prevail and a bloom is an absolute certainty since 2001. One thing that I will never forget is seeing every mangrove tree in the creek just inside the mouth of Wathumba Creek on the north western side of Fraser Island, dead from contact with another type of algae that I am still unfamiliar with. That was in 2004 and was at a time when Fraser Island was surrounded entirely by various algae that made any sort of ocean recreation virtually impossible.

There are some extremely frightening articles published on algal blooms that warn of the decimation of aquatic ecosystems in the near future. From my own observations I see no reason whatsoever to dispute these claims. The Healthy Waterways Strategy, targets 2026 as being when coastal algal blooms will have been eradicated in South East Queensland. To me this seems fanciful when the main contributors of nutrients to our waterways are still contributing unmolested the same quantities and varieties of nutrient. The population of the Sunshine Coast is the fastest growing in Australia and an increase in nutrient levels is certain. So to be realistic, the ambitions outlined in this strategy cannot be achieved at our current rate of progress.

Each level of Government must act now in a coordinated effort at reducing these nutrient levels and to assist depleted species that feed on the algae to increase their population levels. The Healthy Waterways Strategy outlines what needs to be done in a very clear fashion, but knowing what to do and actually doing it seem to be two entirely different scenarios. The current level of investment in reducing the incidence of algal blooms is pathetic and indicates to me they are merely 'keeping up appearances' and putting the problem in the 'too hard basket'. But inactivity now will be increasingly catastrophic as those who are in the know are well aware of.

Having stated how serious the problem of algal blooms is and how much worse it is likely to become, there is still some reason for optimism for the summer ahead. Prevailing south easterly winds should eventually kill off the algaes which will wash on to the shore leaving a clean surf zone. A wet season with average rainfall and hopefully a good low pressure system or cyclone would also assist greatly in eliminating any current coastal blooms, but these are only short term fixes and can't be relied upon. Sooner or later we are going to get back to seasons with prevailing northerlies such as we have experienced for most of this decade and that is when we will see how bad things have become. However, if over summer we experience hot calm conditions, then new blooms are guaranteed to occur.

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