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Sudden penguin deaths – can you help?

Ursula Ellenberg, February 20, 2013
 

The endangered yellow-eyed penguin is endemic to New Zealand. The South Island population is monitored closely and fluctuates between 400-600 breeding pairs. The Otago Peninsula, on the south-east coast of the South Island, is with 181 breeding pairs (2012-13) an important population stronghold for the species.

Since 21 January 57 yellow-eyed penguins have been found dead. Most birds were in excellent condition and experienced breeders. Dead birds had generally empty stomachs and often traces of vomit around their beak. In some cases blackish faeces stains were apparent.

Post mortems and histological examinations showed no evidence of an infectious disease or trauma. Avian malaria has been ruled out though some virology testing is still being undertaken. Currently, acute poisoning possibly via biotoxins is being considered the most likely cause of death.

The event is so far localised to the Otago Peninsula, down-current from Dunedin city’s sewage outlet. Several weeks of warm and unusually calm weather may have resulted in the development of a harmful algae bloom (HAB). However, no other seabirds are known to have been affected.

Since yellow-eyed penguins are almost exclusively bottom foragers we suspect any toxins associated with this event may have been ingested at the seafloor. Three freshly dead birds have been tested for a range of biotoxins, usually associated with HAB (e.g. domoic acid, brevetoxin, see below); but results all came back negative.

We are keen to hear of any ideas as to what could have caused such rapid and unexpected deaths. Apart from biotoxins – can you think of any other toxic agents (probably of anthropogenic origin) that could be responsible and thus would be worthwhile testing for?

List of biotoxins tested for so far: domoic acid, epi domoic acid, gymnodimine, azaspiracid, okadaic acid, DTX-2, DTX-1, PTX-2, PTX-2 seco acid, yessotoxin, hydroxy yessotoxin, homo yessotoxin, 45 hydroxy homo yessotoxin, YSP toxin 1, Brevetoxin B2, S-deoxy-Brevetoxin B2

Thanks heaps!

Comments ( 4 )

Silje-Kristin Jensen

I can see that you have not screened for saxitoxin. Is there a reason for this?

This is a neurotoxin and will cause death. It is known to kill birds although this toxin is still hard to understand.

Saxitoxin is produced by the dinoflagellate Alexandrium spp. (and others....). Alexandrium is also known to have a resting stage as a cysts laying on the seabed.

Might be worth looking into? I'm doing my PhD on biotoxins and would be happy to answer any question or send relevant papers...

Stefanie Grosser

Hey Ursula,

just found this webpage. Maybe you can manage to contact a vet from WCS and see what kind of toxins they have dealt with and what the symptoms are. http://www.wcs.org/conservation-challenges/wildlife-health/care-for-animals-in-the-wild/penguins-and-other-seabirds-in-patagonia.aspx

Maybe it's worthwhile doing a search by symptoms as well, see if you can find someone specialised in toxicology. Could be even human medicine. Symptoms would probably be the same just more severe. And industries that are connected to the Dunedin sewage system -> what substances are most likely to enter the system and cause those symp.

Have the birds been tested for heavy metals?

I know you probably don't have the time to do searches like that though :(

Just thinking, maybe it would be worth it to involve the uni in this. Could be a great project for students in zoo or chem. Little bit like a CSI investigation. lol. But the more people who know about it and do some google searches the better I guess.

You said you observed blackish feaces which might hint at internal bleeding. Wouldn't that have been obvious for the pathology lab?

Don't know if any of this makes sense but I reckon it's better to get ideas out, however stupid they me be, than missing something important.

Cheers Stef

Tony Bicknell

Hi Ursula,

I asked our environmental chemist what they thought and got these comments:

".... they haven’t looked into the Palytoxin group of biotoxins (including PlTX, 42-hydroxypalytoxin, homo-, bishomo-, neo-, deoxypalytoxin, ostreocin-D, ovatoxin-A and mascarenotoxins (A and B)) – very toxic compounds which I believe have previously been found around New Zealand. These toxins are predominantly produced by marine zoanthids (Palythoa ssp.) and dinoflagellates (Ostreopsis spp.). Incidences of (human) exposure have been linked to touching zoanthids, consuming seafood – fish and crabs. Death is extremely fast and usually due to heart failure. So it rather depends on what Penguins eat (I don’t really know anything about penguins). If penguins have a very different diet from other seabirds then it may explain why it’s only affecting them"

"My first thought was also biotoxins from HABs (e.g. domoic acid); but this has been ruled out already I see. Without details I can only assume the methods used were adequate (our studies (e.g. Downes-Tettmar, N., Rowland, S., Widdicombe, C., Woodward, M. and Llewellyn, C. (2013) Seasonal variation in Pseudo-nitzschia spp. and domoic acid in the Western English Channel. Continental Shelf Research 53, 40-49. [doi: 10.1016/j.csr.2012.10.011]) showed that methods used for assaying shellfish etc for domoic acid (e.g. ELISA) were not-at least in our hands- the best for assaying algae and maybe not in birds either). LC-MS was the best method we found. But I expect experts more knowledgeable than me about biotoxins have done it in NZ.

If something on the bottom floor is suspected- has analysis of the sediments been done in an area where the birds are known to feed-or is that too big an area to be possible? Water soluble compounds would obviously tend to stay in the water, but hydrophobic compounds might sink with sediments, especially if sewage-related"

I hope these help, Regards Tony

Ursula Ellenberg

Ursula Ellenberg

Thank you for all your great feedback.

Unfortunately, the event is not over yet. Another adult yellow-eyed penguin from the Otago Peninsula has been collected sick on Saturday afternoon and died early Sunday (3.03.2013). Mel Young described symptoms as “panting hard and the feet, beak and eye margins were very reddened but cold to the touch. The exhalation was wheezy […]”. The bird had extremely orange eyes (usually yellow, hence the name) and vent was blood stained. The post-mortem came back today confirming blood in the intestinal track and else symptoms were similar to the other dead birds sent up.

Any protozoa or bacterial infection including Avian Cholera has been excluded in all cases. (Thanks again Lisa for you interesting paper on Cape Cormorants!). Liver samples are currently being tested for heavy metals and we expect results back this week. Virus screening is still underway for completeness; however, experts note that they “can’t think of a virus that would kill these birds without leaving some footprint”. Hence, we are back to (bio)toxins as the most likely cause of death. Saxotoxin has been screened for in 3 birds and also came back negative (Thanks Silje-Kristin!).

Interesting to learn that toxin screening results will greatly depend on the methods used – still in the process of chasing this up. Thank you Tony, also about bringing up the Palytoxin group of biotoxins! Sediment samples are currently being screened for heavy metals, but kept for further toxin screening (we have not yet found the money for this).

While fixing water samples for plankton analysis (currently underway to narrow down which other biotoxins we should be screening for) using lugol’s iodine we noticed that most bottles turned brown in colour as they do with iodine, while one sample bottle – interestingly the one from the bottom water sample closest to a sewage outlet (which is at the seafloor) turned bright pink. The bottles were all made from type 2 plastics (high-density polyethylene). Any ideas what could cause such a colour reaction?

We are currently trying to narrow down the potential toxins we need to screen for so as to keep related costs manageable. As such we are interested in any toxic agents that could bypass the recently commissioned biological stage of the sewage treatment without causing the stock to collapse completely (it has been instable throughout January). Several other potential sources of toxins are also currently being investigated.

Thanks again for all your help and keep up the great feedback!