Jawbone Marine Sanctuary

December 17 2011……Successful Jawbone Conservation Activity Day

Near perfect warm weather and well chosen tide meant that a dedicated group of about 15 successfully carried out two different activities.

Jawbone Committee members were joined by 5 volunteers from the Australian Marine Conservation Society and 4 others …and we picked up another willing volunteer who spotted us on the day!

First snorkellers went out on the falling tide to carry out the Great Victoria Fish Count.  Not a lot of fish were seen, but this is probably not unusual for this time of the year.  We saw the usual Banjos, Stingarees, one large Eagle Ray, a large flathead, many marbled toadfish and Moonlighters …none of which are on the GVFC list!…but we also saw Dusky Morwong and some large schools of our beloved Zebra fish, including some juveniles.

 After a BBQ under rather windblown shade (which we were extremely grateful to have given the 5 hours we spent out in the midday sun!), we divided into groups to carry out the culling of Asterias. (Northern Pacific Seastar) 

This was carried out in fairly discrete areas of the Bay, concentrating on the shallow seagrass beds along the Sandbar, along the rocks on the east side of the Bay, in the Midbay reefs and in the seagrass and reefs of what we call Rocky Bay.   All up we gathered (under our DSE permit) 37 Kg of this invasive, voracious starfish!  Most of these came from the seagrass beds along the Sandbar, which is where we first saw the incursion last winter. We were also keen to remove all we found from further out in the middle of the Bay on the mussels, to protect the mussels and create a buffer zone to slow down further incursion into the shallows.   Hopefully if we carry out this activity several times a year we should be able to protect the cockle beds in the shallow seagrass.

We all agreed that the day was a huge success and that it could make a good activity for fuller community engagement or a school group (under supervision!)….

*****NEWS****

Northern Pacific Seastar Cull – Sunday 15 April – meet at Mullins Court Carpark at 9am. Please register at Contact Us.

What a combo!

On 17 December 2011 – You get to count fish at 10 am and then help remove NP seastars at 12.00.

Also a BBQ in between. Please see below and be sure to ‘contact us’ to register. This is so we can let you know if it is cancelled on the day.

The Northern Pacific Seastar

The Northern Pacific Seastar (Asterias amurensis) is an introduced marine pest that is currently found in two locations inAustralia: the Derwent Estuary inTasmania (1992) and Port Phillip Bay (1998) inVictoria.

It’s considered a serious pest inAustraliabecause of its impact on native marine ecosystems and marine industries such as shellfish farming.

Northern Pacific Seastars are known to have a negative impact on native marine organisms, mainly because they are voracious predators that eat a wide range of native animals.

In Tasmania’s Derwent estuary for example, they have become the dominant invertebrate predator and have been directly implicated in the decline of the endangered spotted handfish (Brachionichthys hirsutus). It’s suspected that the seastars prey on handfish egg masses, and/or on the sea squirts (ascidians) that handfish use to spawn on.

The Northern Pacific Seastar has the potential to rapidly establish large populations in new areas. For example, recent estimates indicate the population had reached 12 million two years after they were first detected inPort Phillip Bay. Tens of thousands of seastars have been removed in eradication attempts, but with little impact on overall population numbers. Even inJapanwhere the seastars are native, some populations show ‘boom and bust’ cycles, reaching plague proportions for two to three years followed by rapid declines.

What can be done about this introduced pest?

Because the seastars are highly productive (females release up to 20 million eggs each),100 percent of the population must be removed for an eradication attempt to be effective. If just a few individuals are left the population will successfully breed.

The Northern Pacific Seastar is now established inPort Phillip Bay. The seastars are present as adults and larvae inPort Phillip Baywaters at various times of the year.

Current technology is unable to eradicate this species from the Bay without causing severe side effects to the environment. Therefore the current priority is to stop this marine pest from spreading to new areas alongVictoria’s coastline.

What can be done at Jawbone Marine Sanctuary?

Jawbone Marine Sanctuary has been set aside as a marine protected area because it contains a range of ecosystems that are unique in Port Phillip and that were protected for over 100 years when the Merritt rifle range was active.

While the Northern Pacific Seastar is unlikely to be eradicated, with ongoing attention and removal of the Seastar we may be able to protect sensitive areas from this predator’s impact, and prevent it from becoming a dominant predator.

Note: The Northern Pacific Seastar is often confused with the native 11-armed Seastar, an important local species. This confusion is one of the reasons the Northern Pacific Seastar can only be removed under permit and with proper supervision. More detailed information about the 11-armed Seastar and other seastar species will be provided to all who take part in this activity.