Caulerpa now in BOI

[CarpeDiem 356]

1 hour ago, K4309 said:

Erm, so how did the NZ native species of Caulerpa get here?

Good question.  Our native Caulerpa are found only in Australia and New Zealand.  No where else in the world has them. 

I have very little idea and certainly no proof.  I know there's an awful lot of marine species that are native to both Australia and NZ only.  Science tells us that sea weed has been around for over 1 billion years and that the two countries were a super-continent 80 million years ago.

The more interesting question is how did it get to Gondwana in the first place and what wiped it out on it's evolutionary path from where it originated. 

 

 

 

[Ex Machina 340]

 Anywhere could’ve been the vector not just Auckland . If for example if it was off an anchor the boat could’ve have been heading north , stopped at mercs first then Barrier . That puts every harbour and domesticated inlet south and inshore of the mercs in the realm of possibility 

[K4309 145]

1 hour ago, CarpeDiem said:

Good question.  Our native Caulerpa are found only in Australia and New Zealand.  No where else in the world has them. 

I have very little idea and certainly no proof.  I know there's an awful lot of marine species that are native to both Australia and NZ only.  Science tells us that sea weed has been around for over 1 billion years and that the two countries were a super-continent 80 million years ago.

The more interesting question is how did it get to Gondwana in the first place and what wiped it out on it's evolutionary path from where it originated. 

 

 

 

I'm actually quite interested in these native species of caulerpa, but haven't been able to find any information on them yet. Any google search for anything related gets buried in stories about the exotic species. To compare attributes to the exotic species, particularly range, habitat and growth rates.

I was under the impression that both exotic species were toxic, both from the expert at the boatshow and comments on here. So I was surprised to see that statement on the MPI site that they are not toxic, or at least they do not cause toxicity in edible fish. It is not actually clear from the statement, other they don't have the toxin the main aquarium species has.

IF they are not toxic, then the question is what is the main problem with them? Obviously they out-grow and smoother, esp over sand, but rocks and everything else. But for something to out-grow everything else, it needs to be better adapted to the specific environment than everything else. The same concerns applied to fan worm. In my view, fan worm is not that prolific. I see it occasionally on the beach and while free diving / spear fishing, but it certainly has not smoothered the entire sea floor.

One of the stated concerns from MPI on the caulerpa is that it will destroy the habitat for nursery fish. But nursery fish need weed to hide in. So which is correct?

The AC / boatshow expert did say that kina go sterile if they eat caulerpa (which didn't sound like a bad thing to me), but on reflection, its not entirely clear which species he was talking about. As far as I can tell, all current research is on the main aquarium variety. For natural control, snapper are carnivores, but Parore are herbivores. They are in plague proportions at my fav spear fishing spots, and incidentally are really good eating if you don't pierce the gut cavity (not as easy to prepare and fillet as snapper, but really easy to shoot).

There is a native sea slug (nubibranch) that eats it...

It would be good if the ecosystem adapts to caulerpa, and it turns out to not be a major issue. Certainly NRC are making big noise about it, but that is also very closely related to them demanding more funding, which can also be construed as empire building.

So far it appears fan worm is good at filtering water, and hasn't gotten out of control. Caulerpa is good at absorbing nitrogen and phosphorus (so also improves water quality), and may well be a solution to kina barrens. Who knows?

I'd love to go out to Bland Bay or Whangaparapara for a spear fish and see for myself what is going on, but the CAN notices makes it a bit complicated. If only they would install mooring bouys for public use, and we could all move on.

 

PS, it is interesting that we have TWO new exotic species here. That says to me that if the vector was a one off thing like a boat anchor, getting two species was just plane bad luck. If it was an ecological vector, like the marine heatwaves, la nina and the East Auckland current, it would be more plausible to get two new species.

[CarpeDiem 356]

32 minutes ago, K4309 said:

I'm actually quite interested in these native species of caulerpa, but haven't been able to find any information on them yet. Any google search for anything related gets buried in stories about the exotic species. To compare attributes to the exotic species, particularly range, habitat and growth rates.

These are the two native NZ species.

https://en.wikipedia.org/wiki/Caulerpa_articulata

https://en.wikipedia.org/wiki/Caulerpa_brownii

32 minutes ago, K4309 said:

I was under the impression that both exotic species were toxic, both from the expert at the boatshow and comments on here. So I was surprised to see that statement on the MPI site that they are not toxic, or at least they do not cause toxicity in edible fish. It is not actually clear from the statement, other they don't have the toxin the main aquarium species has.

It is toxic to NZ fish and therefore has no natural predators in NZ.  Assuming the NZ fish were able to adapt to it then they would likely store the toxin on their flesh potentially making the fish toxic.  MPI are saying this will not happen.  However as we know nature has a way of adapting.

Apparently it is not toxic to humans in small doses according to tests done on rats (can't find the reference now).  However every publication says "do not eat"....

[aardvarkash10 866]

37 minutes ago, CarpeDiem said:

Apparently it is not toxic to humans in small doses according to tests done on rats (can't find the reference now).  However every publication says "do not eat"....

so a sushi empire is out of the question then.

[K4309 145]

1 minute ago, aardvarkash10 said:

so a sushi empire is out of the question then.

I still think it should be included in the Emissions Trading Scheme.

[K4309 145]

39 minutes ago, CarpeDiem said:

 

Apparently it is not toxic to humans in small doses according to tests done on rats (can't find the reference now).  However every publication says "do not eat"....

I never feel very happy or safe when I read statements like that. It is safe. for rats. and in small doses. Apparently it makes kina sterile...

Thanks for the links.

[harrytom 618]

Very possible it came from the viaduct. Remember they dredge it and the dumpings were off cuvier island

So may of been here longer than we think.

[CarpeDiem 356]

21 minutes ago, harrytom said:

Very possible it came from the viaduct. Remember they dredge it and the dumpings were off cuvier island

So may of been here longer than we think.

Pretty sure that dumping ground was only approved at the end of 2022 and it got tied up in court battles.

That dumping ground also as far from the barrier as the Ports of Auckland are.

[harrytom 618]

Nothing new,Australia has had it since 2015 or been monorting it since 2015?

https://digital.library.adelaide.edu.au/dspace/handle/2440/104681

Populations of the green marine macroalgae Caulerpa taxifolia and Caulerpa cylindracea have invaded and spread throughout Mediterranean after they were introduced from Australia. In Australia, these tropical to subtropical species have established invasive populations in New South Wales, South Australia, and most recently, for C. cylindracea, in Victoria. Significant efforts have been made to elucidate the invasion history and geographic source locations of Mediterranean populations. The same effort has been lacking in Australia. Both species have provided challenges for molecular ecologists because of their predominantly clonal reproduction and low genetic variation within invasive populations in the case of C. taxifolia, and very high intra-individual genetic variation in C. cylindracea.

 

. I have also shown that the response of native and invasive Caulerpa spp. to climate change scenarios indicates that invasive populations of Caulerpa may become more abundant and continue to expand their invasive range in the future. I also identify the limitations of this body of work and the issues encountered in the program of research, and discuss future research possibilities for invasive Caulerpa species.

[harrytom 618]

Haha been here since 2021 but no action till 2022

https://niwa.co.nz/news/marine-invader-caulerpa-triggers-biosecurity-response

Two new species of non-indigenous algae were discovered in mid-2021, identified by NIWA researchers as Caulerpa brachypus and Caulerpa parvifolia. 

New Zealand has some native species of Caulerpa but the two species identified in 2021 showed similar characteristics to the highly invasive Caulerpa taxifolia that has been problematic overseas. Caulerpa taxifolia has been listed as a Notifiable Species under New Zealand’s Biosecurity Act since 2001. 

The two new species of Caulerpa were found in a variety of habitats and depths near Aotea. They covered large areas of seafloor and appeared to spread quickly.  

Both species were given the status of Unwanted Organisms under the Biosecurity Act in September 2021. 

[waikiore 349]

Umm the current dumping zone is just behind the Barrier near the old munitions dumping area -not way past Cuvier like what was done in the eighties and nineties, this is used by Pine Harbour , Westypark and others from around Auckland-which is of course why the Barrier residents and Iwi were so up in arms about it being granted permission.

[CarpeDiem 356]

1 hour ago, waikiore said:

Umm the current dumping zone is just behind the Barrier near the old munitions dumping area -not way past Cuvier like what was done in the eighties and nineties, this is used by Pine Harbour , Westypark and others from around Auckland-which is of course why the Barrier residents and Iwi were so up in arms about it being granted permission.

Not according to the this document from POAL.

The Cuvier Dump Site ranges in depth from 500m to over 1200m and the seabed is likely to be primarily mud (60- 80%) and sand (20-40%), similar to the material being dumped. Since World War II the site has been used for the disposal of ammunition, decommissioned vessels, and dredged material from Auckland marinas. POAL used the Dump Site for the disposal of dredged material in the 1990s. Information on the ecology of the disposal area is limited because of its isolation and depth.

 

[waikiore 349]

Thats a different site from that which I am referring, that is the old one we have always towed to.  

[harrytom 618]

3 hours ago, waikiore said:

Umm the current dumping zone is just behind the Barrier near the old munitions dumping area -not way past Cuvier like what was done in the eighties and nineties, this is used by Pine Harbour , Westypark and others from around Auckland-which is of course why the Barrier residents and Iwi were so up in arms about it being granted permission.

Yes that why I emailed Eugenie Sage,she was Minister at the time for eviroment?Got a wishy washy reply as I said with fan worm being in Auckland and dumping so close to barrier,wont be long before fan worm is established.

[Steve Pope 243]

6 hours ago, Ex Machina said:

 Anywhere could’ve been the vector not just Auckland . If for example if it was off an anchor the boat could’ve have been heading north , stopped at mercs first then Barrier . That puts every harbour and domesticated inlet south and inshore of the mercs in the realm of possibility 

I believe the fanworm first was found in Lyttleton harbour, long befor it was discovered in Auckland.

[Black Panther 1,503]

12 hours ago, CarpeDiem said:

Your question suggests that it has?

It sinks and it doesn't survive at depth. The world's currents take around 500years to do a full circle of the planet so it's had 23 million years to get to our coast.  In that time it hasn't made it across vast distances. 

New Zealand isn't special in this regard, it also hasn't made it (naturally) to West or East Coast of the Americas which are a sh*t load longer than NZs coast.  As we've read in this thread it also hasn't made it naturally into the Med. 

I suspect that the warm surface currents of the tropics only carry it so far before it gets pushed to depths that it cannot survive and turns back into ocean nutrients.

Sorry. Let me be clear. Having arrived somewhere, how did it spread.

Yes modern international shipping means things get moved to new areas across what were natural boundaries..

But once established the new organism will spread to every available niche, and the methods for this spread existed long before humans and boats. 

I thought it was this "secondary " spreading we were discussing.

[CarpeDiem 356]

39 minutes ago, Black Panther said:

Sorry. Let me be clear. Having arrived somewhere, how did it spread.

Yes modern international shipping means things get moved to new areas across what were natural boundaries..

But once established the new organism will spread to every available niche, and the methods for this spread existed long before humans and boats. 

I thought it was this "secondary " spreading we were discussing.

Both conversations seem to be taking place simultaneously  

Once introduced it can move on coastal currents.

According to MPI, their theory is, that as it can't survive below 40m and it sinks, it's very unlikely to spread to the rest of the gulf on it's own.

I have not read any reason for why they reached that conclusion.

I guess we wait and see cause there is nothing else to do

[Psyche 537]

Bit of a contradiction there by MPI, if it can drift on currents then currents may take it to Coromandel and beyond surely. How did it get to Barrier, if it was via yacht then we would expect have some sightings at one of of the popular mooring areas.

[K4309 145]

37 minutes ago, Psyche said:

Bit of a contradiction there by MPI, if it can drift on currents then currents may take it to Coromandel and beyond surely. How did it get to Barrier, if it was via yacht then we would expect have some sightings at one of of the popular mooring areas.

Bland Bay isn't the most popular anchorage, yet it appears to be the epicentre of the outbreak. That just doesn't make sense, given MPI's argument that it is / has / can be spread by anchors.

I would argue it is far more logical that it got to Bland Bay by some other means, and that there is a risk that anchors could spread it around the rest of the Gulf.

The other thing that confuses me substantially (which isn't hard). How can it be in Tryphena, Bland Bay and Whangaparapara but not in Bowling Alley Bay or Fitzroy itself?

To almost answer my own question, we all know the East Auckland current sets southwards, and low and behold, dead down current, it has been found at Gt Merc.

That, and this whole argument that it sinks, so can't be spread by currents doesn't sound fullproof. All it needs to do is grow on a log, mussel bouy or any other piece of floatsome that washed into the Gulf in any one of the several major rain / flood events, and the caulerpa can be hitching a ride to any bay it wants. Include Rawhiti.