OVER THE YEARS LAND BASED PRACTICES HAVE CAUSED MAJOR MARINE HABITAT LOSS IN
MORETON BAY AND PUMICESTONE PASSAGE.
European Fishing History Pumicestone Passage. First land sales Pumicestone Passage l848 (150 years of white settlement)
From the writings of Tom Welsby we have a picture of what Pumicestone Passage fishing use to be like 150 years ago. From good catches of the Bays finest sea Whiting at Skirmish Point, Welsby also fondly talks of regularly catching 5 kg Snapper, Squire, Bream and Blue Spot Parrot, off an oyster laden rocky ledge with a 40 feet deep reef, between Poverty Creek and Mission Point. From this rock ledge on the Bribie Island side, all the way to Skirmish Point, good catches of Bream, Whiting, and Flathead were regularly caught on the flood tide. Other fish mentioned as being frequently caught were Catfish, Little Blue Sharks, John Dory, Groper, Estuary Cod and Sawfish.
Loss of Fish Species
From these reports of the 1850s to the 1930s, we can see that there have been changes (other than Ningi's mosquitoes). Gone are the prime oysters, gone are the crab catches above the water line of 6 + mud crabs in a quarter of an hour, and who of us lately has caught Kingfish, Snapper Parrot, and Sawfish in the Passage?
With the colonisation of the area in the I860s we saw the first of the land clearings with other major events occurring after the world wars. These massive catchment clearings occurred in many cases to the waters edge, leading to increased creek bank instability. This, combined with increased pasture/farm soil erosion, has led to the major sedimentation of the Passage and its Creeks. The 40 feet deep rocky reef (coffee rock) north of Poverty Creek, so fondly spoken of by Welsby, is now only some 20 feet deep, a little over half its original depth.
The real rub comes with the combination of two factors, land clearing, poor creek together with the Passage flushing, and the northerly drift of sediments through the Passage from the Bay. These sediments are high in nutrients and heaven knows what other nasties. To mention just one, Dieldrin levels in the Passage sediments as specified in the ANZECC Disposal Guidelines 1998 are high halfway between the screening level and the maximum. The half-life of Dieldrin is hundreds of years, and we know that resuspension of sediments and their contaminants occur in the water column with wave actions in the shallow waters.
Major Study Addresses some of the Issues
The Brisbane River and Moreton Bay Wastewater Management Study has recently completed the mapping of Bay sediments and nutrients. A team of Scientists and other experts from almost all Universities in South East Queensland, and a sprinkling of others from Southern State Institutions, are conducting this study.
The aim of the study is to link science to management, and to produce a management tool by integrating all of their various data sets into a functional management mapping tool, so that the regions stake holders can use it in the areas strategic development and in the Moreton Bay Marine Park planning. Findings to date indicate that there is no single driving issue - rather, a grouping of problems, which include nutrients, sediments and toxicants.
Sunfish believes that the Bay and the Passage marine ecosystem, as we know it, is in the balance. We urge Government, Councils, Communities and Catchments Groups, to work together, to achieve the studys goals and recommendations on time.
Nutrient Rich Sediments Help Destroy Seagrass and Fish Habitats
Here are a few figures to give you a general idea of the issues at hand. Brisbanes 1.2 million population is 8 fold that of 1976. During this period the water quality of the Brisbane River has declined with a 4-fold increase in sediment concentrations. The 1996 Brisbane River flood monitoring, a 2-day event, indicated that a 1 million tonne sediment slug entered the Bay, thus changing the bays predominant zooplankton structure for the following two weeks as a result of the dispersal of the phytoplankton bloom.
So the saying 'Pollution by dilution', is not true. A better phrasing would be 'Concentrated pollution by dilution'.
Turbidity and these nutrient rich sediments have led to the total loss of seagrass in Bramble Bay, more recently in the Caboolture River, and now Deception Bay is in the balance. So in the last 40 odd years we have lost most of our seagrass in the northern end of Moreton Bay. The remnant seagrass in the area now only exists east of the Caboolture River - from Beachmere to Sandstone Point on Pumicestone Passage. Remember, loss of seagrass = loss of fish and crabs in those areas.
Algal Blooms 'Lyngbya' Destroy Fish Habitat
These remaining Sandstone Point/Beachmere seagrass banks have in the last 3 years been reduced by 50% due to a lyngbya majuscula (Blue green algal bloom). Greg Savage, a professional fisher from Bribie, alerted the Catchment Coordinating Committee to the algal problem and in turn, the Moreton Bay Study Group. Their Dr Judy ONeill (UQ) has indicated algal bloom requirements appear to be 16 parts nitrogen (N), 1 part phosphorus (P), and 0.01 part iron (Fe). Because atmospheric N2 gas dissolves in water N2 fixation occurs, ie. Lyngbya acts like a legume. Apart from water temperature above 20° C, the potential driving force behind these blooms is the limiting nutrient Phosphorus (P), and the catalyst a little iron (Fe), both leaching from exposed Acid Soils, from creeks onto Bribie and Godwin Beach.
Lyngbya smothers seagrass habitats and so reduces fish and crab numbers. Those who are unfortunate enough to have handled it know it can cause large painful ulcer-like sores or a rash, and associated complaints such as swollen eyes and asthma. Washed up on the beach, it smells like raw sewage. It is a known carcinogen, and may have links with cancerous growths in the throats of the sea grass grazing Hawks Bill Turtles. It has also been found growing on Coffee Rock formations off Indian Head and Rainbow Beach. Fortunately in these areas there are no seagrass beds, so there has been no apparent habitat loss in the area. Fraser Is. Park Rangers talk of 1300 cases of lyngbya (fireweed) related problems this year.
Aquaculture / fishing Concerns Re. Extractive Industry push on Pumicestone Wetlands.
Local Bullock Creek Aquaculturist, Peter Spindler, is particularly concerned regarding, lyngbya and liberated metals affecting his prawn and fish hatchery farm, as a result of a proposed sand mine adjacent to his Donnybrook farm on the sensitive Elimbah Creek flood plain wetland.
CSRs proposed mining operation which aims to dig a deep hole, 50 hectare (123 acres) in area and 18m (60ft) deep, across the flood plain to a distance within 200m of Bullock creek and 150m of Elimbah Creek, will employ 7 persons.
There has been no hole dug this big and so deep this close to a Fish Habitat B zone.
We know from studies that the area contains acid soils and that there is direct hydrological contact between this site and the adjacent creeks and Passage. Many are concerned that CSR says there are no adverse issues regarding its proposal and that it will only exchange information that is positive for its application. Past mining history in this area indicates otherwise; with dredge pond waters at times registering an acidity level of 3 pH and lower, high iron levels in ponds, together with the mining of gazetted roads and bund wall collapses, as well as acid sediment flows of non-compactable residual mining colloid seeping into adjacent creeks; these are a few examples. Surely there are other places to mine sands. We don't want another Trinity Inlet issue here on hallowed recreational fishing grounds.
We believe here lies some real concern for Pumicestone Passage,
This is the only 'Recreational Fishers only' Marine Park fishing area in Queensland waters.
You can see from the above points the outlook doesnt look good. Sunfish Queensland is concerned, regarding the continued loss of habitat due to exposure of Acid Soils.
* The Queensland Government to endorse in principal the 'Queensland Acid Sulphate Soils Management Strategy', and to (a) prepare a State Planning Policy, (b) nominate a lead agent, (c) Refer funding to the budget process.
* The Commonwealth Government again financially to support national action on Acid Sulfate Soils
* That the precautionary principle be adhered to, particularly if there is doubt regarding environmental issues relating to proposed developments on sensitive wetland areas adjacent to fishing habitats.
Sunfish North Moreton.
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