Photo taken from Mud Islands with Pelican1 and Authur's Seat in the background. This Port Phillip Bay landmark was the first site that Mathew Flinders climbed to orient himself, after sailing into the bay in 1802.
Mud Islands has become one of my favourite stops of the Two Bays project. You become aware of the islands before you see them by the many birds overhead winging their way there. They are an important home and breeding ground for Pelicans, Ibis, Terns, Cormorants, Royal Spoonbills, Storm-Petrels and Silver Gulls.
They are made up of three shrubby islands that rise up out of and are part of the Great Sands in Port Phillip Bay. The islands enclose a shallow tidal lagoon that is fringed with salt marsh. Despite their name the islands are in fact made up of shelly sand and resemble an atoll. The islands are situated closely to the Heads.
The islands were formed by wind and wave action and kept firmly in place by outcrops of phosphate rock. The phosphate rock formed beneath the guano deposits (bird droppings) as guano leached below and combined with shelly sand below to form hard calcium phosphate. This rare rock type is able to withstand marine erosion. The islands are reknown for their bird life and it is interesting to note how strongly birds feature in the creation of the islands themselves. When visiting you can almost imagine a conference of the birds type scenario where they all decided to contribute to building a site for themselves.
The islands are protected under various conventions including the Ramsar and the Register of the National Estate. They are managed as part of the Port Phillip Heads Marine Park by Parks Victoria.
Pelican1 headed out from Queenscliff with a new young Skipper learning the ropes. The boat was almost as full as the belly of Pelican is surveyed to hold (in enclosed waters). Including crew we were 44 people. I have observed since the end of this year's Two Bays project that the period of the program contained some of the best possible weather. If we had held it any earlier or later we would have lost days to bad weather. The winds were perfect to visit the islands as they cannot be too strong to be able to do the observing work and to land people safely in the dinghies. It was in fact, one of our loveliest days on the water.
Morning scene on the way over to the islands. Dr Jan Carey
creating a slide plate to check the cell structure of the Codium species (also known as Broccoli weed or even more endearingly, Dead Man's fingers) on the table, as it is only through seeing the cellular structure that you can tell whether it is the introduced species
The image below was taken by Chris Hayward from Parks (standing 2nd left in pic above) which shows the waisted cellular structure of the invasive Codium fragile. The pest species originated in Japan and probably travelled here in ballast water. It presents a danger to native species by taking over their habitat. I have also read
that overgrazing by sea urchins may provide sufficient disturbance to native seaweeds to enable their getting a toehold.
And the real thing below (Dead Man's Fingers) on the shores of Mud Islands.
Jan Carey is currently working on an ARC linkage grant to develop optimal monitoring methods for citizen scientists to detect non-indigenous marine species. She has been coming on board Pelican for the last few years with her PhD student Kim Millers. Kim is writing her thesis on developing methodologies for working with community to detect pest species. On this trip to Mud Island they were both on board to gather more data with members from Sea Search
and the Friends of Mud Island
group. Below, Jan shares her knowledge with the group of volunteers.
Below Jan is setting up the Marine Pest survey site.
A picture of a star of pest stars. The Northern Pacific Sea Star
has invaded Port Phillip and their numbers apparently have more combined weight than all of the rest of Port Phillip's biomass put together! Anecdotally the volunteers reported more numbers from our counts from last year.
Never confuse the Northern Pacific Sea stars with our indigenous 11 armed star fish below. One of the Parks rangers shared the story, that in early media reports about the Northern Pacific Sea stars, the newspaper posted a photo of our Indigenous sea star and well meaning locals pulled many of the wrong kind out of the water. There were also early attempts to eradicate the Pacific sea star by chopping them in half and then throwing them back into the water. A big mistake as they can regenerate from a single leg.
On board too were Peter Menkhorst and volunteers for Birds Australia to carry out some shorebird monitoring. Below Peter leads the way to the inner lagoon of the Islands.
Peter was the first person to record pelicans breeding on the islands in 1983 and has been monitoring the bird community on Mud Islands for 28 years. He has recently completed a survey of the 10 waterbird species that now breed there. Here are some quotes from Peter from a DSE Media release - 22 Dec 2010 about Mud Islands.
“Mud Islands have grown dramatically in importance as a waterbird breeding site over the past two decades with an estimated 95,000 pairs, belonging to 10 species, nesting on the islands in 2008 and 2009. The most abundant species are the Straw-necked Ibis (with 56,000 nests) and the Silver Gull with perhaps 30,000 nests,” Mr Menkhorst said.
“When I first found pelicans breeding on Mud Islands there were only 10 nests, but the number of pelicans breeding in Port Phillip Bay has risen to around 800 pairs as the species becomes increasingly adapted to living in close proximity to humans.”
“The breeding pelicans are now using the islands for around 10 months of the year and, if possible, we’d like people to keep away from the breeding colonies and avoid disturbing the birds with boats or jet-skis.”
“Mud Islands are an amazing sight when the birds are breeding with thousands of birds sitting on nests which are built on the ground or in the low saltbush shrubs.”
“Many Victorians wouldn’t realise that this important bird breeding colony is right here in Port Phillip Bay. We want to increase community awareness of this significant site and we want visitors to respect the needs of the breeding birds and to avoid causing them to leave their nests. Eggs or nestlings in unattended nests are vulnerable to being eaten by other species.”
“They also host significant numbers of breeding Pied Cormorant, White-faced Storm-Petrel and Crested Tern as well as smaller numbers of Royal Spoonbill, Caspian Tern and Little Egret. Over the past 20 years Mud Islands have also lost one species ands are also nationally significant as a feeding and roosting site for migratory wading birds including the Grey Plover, Double-banded Plover, Bar-tailed Godwit, Grey-tailed Tattler, Ruddy Turnstone, Great Knot, Red Knot and Sharp-tailed Sandpiper.”
The friends of Mud Islands, Sea Search and Parks Victoria completed seagrass surveys just to top off a full day of science. On the journey over to the islands and on the return we were treated to Mark Rodrigue from Parks Vic sharing his extensive knowledge of the Bay. I have been lucky to be out on many different days on the water with Mark and it never ceases to astound me how much he knows about life in and on the water but also how brilliantly he can communicate that knowledge to anyone he encounters. I heard him say that Rangers have to complete a degree in shouting, as they are often competing with the elements to be heard.
The gorgeous photo below of seagrass was taken by Michelle Quach
My daughter Aurora snorkelling in the wonderfully clear waters around the islands.
Sailing home our young Skipper turned into a scientist!
The group on our return to Queenscliff pictured below. We had set out to do so many things in one day (the usual Pelican feast) and with the blessing of the weather gods we did it all! We were also travelling on country with Traditional Owners from the Wada Wurrung who had not had the opportunity to visit the island before.