[Catalist] Quality of Water in Tomato Lake in Kewdale WA

[Michael McGarry]

Greetings Science Colleagues,


Motivated by recent deaths of waterbirds, mainly pacific black ducks, I decided to investigate which state and local government departments, and other bodies are responsible for monitoring (and remediating) the quality of water in Tomato Lake in Kewdale WA.


BIRD LIFE URL 1: http://www.birdlife.org.au/bird-profile/pacific-black-duck <http://www.birdlife.org.au/bird-profile/pacific-black-duck>
Back in 2014, ABC News reported on the deaths of thirty ducks at Tomato Lake.


ABC URL 2: http://www.abc.net.au/news/2014-04-09/bird-deaths-avian-botulism/5377918 <http://www.abc.net.au/news/2014-04-09/bird-deaths-avian-botulism/5377918>
I have been informed that the recent deaths of waterbirds at Tomato Lake are most probably the result of an outbreak of avian botulism.


WIKIPEDIA URL 3: https://en.wikipedia.org/wiki/Avian_botulism <https://en.wikipedia.org/wiki/Avian_botulism>
I also suspect that eutrophication caused by a blue-green algal bloom and duckweed growth may have contributed to the outbreak of avian botulism.


Eutrophication is the enrichment of river/lake/swamp water with an excess amount of nutrients. The process induces growth of plants and algae and due to the biomass load, may result in oxygen depletion of the water.


WIKIPEDIA URL 4: https://en.wikipedia.org/wiki/Eutrophication <https://en.wikipedia.org/wiki/Eutrophication>
B-G algae URL 5: https://espace.curtin.edu.au/handle/20.500.11937/1477 <https://espace.curtin.edu.au/handle/20.500.11937/1477>
WIKIPEDIA Duckweed URL 6: https://en.wikipedia.org/wiki/Lemnoideae <https://en.wikipedia.org/wiki/Lemnoideae>
A Contributing Cause of Eutrophication of Tomato Lake Water

I postulate that major cause of eutrophication of Tomato Lake water are the faecal droppings from plague numbers, (up to about 700 ibis in total), which increase the nutrient load of the lake water.


BIRD LIFE URL 7: http://www.birdlife.org.au/bird-profile/australian-white-ibis <http://www.birdlife.org.au/bird-profile/australian-white-ibis>
The seasonal influx of Australian white ibis that fly to Tomato Lake and nest in their habitual rookery can, with abundant food, have three clutches per season and fledge on average 1.4 chicks per nest to produce about 120 white ibis chicks.


Note: A very small population of White ibis lives permanently at Tomato Lake.

DPAW URL 8: https://www.dpaw.wa.gov.au/images/documents/plants-animals/animals/living-with-wildlife/ibis.pdf <https://www.dpaw.wa.gov.au/images/documents/plants-animals/animals/living-with-wildlife/ibis.pdf>
White ibis are causing serious imbalance to the Ecosystem at Tomato Lake.

The seasonal (June to March) plague of Australian white ibis at Tomato Lake that outcompetes other fauna for food and space and shelter is causing a very serious imbalance to the Tomato Lake ecosystem.

An ecosystem is the entire system formed by a community of organisms interacting with one another, and with their non-living (abiotic) surroundings.

The seasonal plague of Australian white ibis at Tomato Lake is contributing to eutrophication of Lake water resulting in the death of water birds such as grebes, coots and ducks, and is noticeably displacing the secretive Nankeen Night heron and Spoonbills with their delightful synchronized feeding.

Bird Life URL 9: http://birdlife.org.au/bird-profile/Nankeen-Night-Heron <http://birdlife.org.au/bird-profile/Nankeen-Night-Heron>
Bird Life URL 10: http://birdlife.org.au/bird-profile/yellow-billed-spoonbill <http://birdlife.org.au/bird-profile/yellow-billed-spoonbill>
At Tomato Lake there are no remaining safe and secure egg-laying sites for female oblong turtles. On a regular morning exercise walk around Tomato Lake, I witnessed a white ibis eat the eggs being laid by a female oblong turtle.

Australian white ibis and ravens eat the eggs of oblong turtles. The eggs of oblong turtles take over 200 days to hatch. As a consequence of lack of egg-laying sites and predation there are no hatchling turtles in Tomato Lake.

The adult long-necked oblong turtles in Tomato Lake are estimated to be between about 15 to about 30 years old as told to me by a Murdoch University student who was surveying the populations of turtles in Perth wetlands.

MUENSA URL 11: http://muensa.wixsite.com/muensa <http://muensa.wixsite.com/muensa>
A possible solution to the sad plight of long-necked oblong turtles in Tomato Lake would be to place thick layers of sand on level lake bank under a dense canopy of shrubs and trees so ibis and ravens can’t see the female turtles’ egg laying.

TON URL 12 http://www.turtleoblonganetwork.org.au/about-them.html <http://www.turtleoblonganetwork.org.au/about-them.html>
Organisations involved in water quality monitoring at Tomato Lake.  

WA DoW [Aquatic Sciences Branch] URL 13: http://www.water.wa.gov.au <http://www.water.wa.gov.au/>
Belmont City Council Office URL 14: http://www.belmont.wa.gov.au/Pages/CityOfBelmont.aspx <http://www.belmont.wa.gov.au/Pages/CityOfBelmont.aspx>
IRASSS URL 15: http://www.irasss.com/index.php?page=case-studies&task=water-aerator-treatment-result-1 <http://www.irasss.com/index.php?page=case-studies&task=water-aerator-treatment-result-1>
SERCUL URL 16: http://www.sercul.org.au <http://www.sercul.org.au/>
The SERCUL Newsletter September 2008 Issue 5 URL 17: http://www.sercul.org.au/docs/SERCUL_Newsletter_Spring_2008.pdf <http://www.sercul.org.au/docs/SERCUL_Newsletter_Spring_2008.pdf>
Reported on a 2008 PAG and SERCUL “Phosphorus Awareness Project.”


WA Schools involved in Wetlands’ Rehabilitation Projects.

Question for Science Colleagues: How many WA Schools are currently conducting cooperative Rehabilitation Projects in their Local Wetlands?


Thanks and Best Wishes,


Michael John McGarry

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