New whale strandings in NZ (part IIA)

[Steve O'Shea]

It's been a long day. This article is from a stranding yesterday, in which 37 whales died; today they restranded, and a further 17 died.

We've been up there doing what we can, and of course doing the stomach contents again. Will post pics shortly. The sound of crying, dying whales is horrible!!

What I can say of 4 of the whales from yesterday's stranding is that they'd eaten 2/3rds of naught (maximum of ~ 3 or 4 tiny lower beaks in the stomachs; one empty). More to follow for sure.

We have 1 manuscript in review right now reporting the diet of a pod that stranded 21 December 2005; we should be able to get the next one out a lot quicker!

 

[corw314]

Wow...that's heartbreaking but invaluable for research purposes. Looking forward to those pics.

 

[sorseress]

That's so sad. Does anyone know if the US Navy was anywhere near? Have you found any parasites?

 

[tonmo]

Steve, sounds like a tragic scene -- thanks for sharing the information here. Definitely curious.

 

[Steve O'Shea]

Just a few pics of the chaos; there are better, but I'm afraid that I had to put the camera down ... (had other things to do)

 

[Steve O'Shea]

A few more

 

[Steve O'Shea]

Last couple. It's a huge affair - people do what they can to save these animals. The NZ DEpartment of Conservation did a truly sensational job coordinating everyone!

 

[cuttlegirl]

How truly heartbreaking, especially the young whales.

 

[Steve O'Shea]

We're almost done on processing these stomach contents, because there was so little in any one whale!

People have criticised our approach because whales are thought to regurgitate the contents of their stomach when under stress, but we do not believe that this has happened in this instance. We propose that hunger is a contributing factor in strandings. These poor things simply had not eaten for a while, and it is quite possible that hunger drove them inshore looking for alternative, shallow-water prey items, with this bad decision leading to their stranding.

Should have something concrete to put online soon.

 

[tonmo]

Wow -- if that is the explanation for these strandings, that's a significant story -- makes you wonder about the health of our oceans' ecology...

Have stomach contents been analyzed in other mass strandings / anything recent that would support what you're finding with this incident?

 

[Steve O'Shea]

Nothing like this Tony (not for New Zealand anyway). Prior to our work on the long-finned pilot whale stranding of Dec 2005 nothing was known of this species diet over here, despite the frequency with which it strands, and the large number of whales that typically strand in any event (nobody has bothered to collect stomach samples). We simply don't have the historic data to support claims that the whale diet is changing, but what we do have is enough information to say that these animals (that died) are rather hungry!

It is possible that this has happened in the past, that mass-strandings over the past century have been caused by localised food shortages, resulting in these animals coming closer inshore and getting in trouble, but there is so much information that we do not have - such as actual measures of prey abundance (squid and octopus).

Of particular interest in this most recent stranding is the diet is made up of a number of deep-sea (>750m) squid, whereas the diet of whales that stranded in Dec 2005 comprised two species only, a relatively shallow-water octopus and squid.

 

[cuttlegirl]

We're almost done on processing these stomach contents, because there was so little in any one whale!

People have criticised our approach because whales are thought to regurgitate the contents of their stomach when under stress, but we do not believe that this has happened in this instance. We propose that hunger is a contributing factor in strandings. These poor things simply had not eaten for a while, and it is quite possible that hunger drove them inshore looking for alternative, shallow-water prey items, with this bad decision leading to their stranding.

Should have something concrete to put online soon.

Can't you back up your findings with measurements of blubber thickness? I know at least with stranded pinnipeds, animals that have not eaten in awhile resorb some of their blubber and when that is gone, move on to resorbing muscle tissue. This process is reversible if caught soon enough but at some point if the animal has started to resorb muscle, it is too late and you can't save the animal.

 

[Steve O'Shea]

I did think about this CG. We've noted substantial blubber on a number of stranded cetaceans; we've never seen 'ribbing' (as in the ribs showing through), but we have noticed quite pronounced ridging, where the blubber is disproportuionately thickened in some places relative to others.

For this reason I've changed the theory somewhat; it might not be starvation, as the whales don't appear to be starved in the traditional sense, but they certainly don't appear to have eaten as much as the calculations say they should have. Hence I tend to use the word 'hungry', and in their quest to find appropriate quantities of food they move further inshore (as offshore searches have yielded little). That's when they get into trouble.

I'm forever trying to think of ways that we can test this theory using some independent information, but getting to the 'guts' (such as liver, kidney, blood, tissue or blubber samples) of these animals proves to be a challenge - more so political than logistical - and it is not appropriate to air these concerns here. We are working on it.

 

[Steve O'Shea]

Just resurrecting this old thread, and renaming it (to keep the titles consistent, and to draw this to a close).

Here's an image someone recently sent me from this stranding (I didn't know about this image). We have completely our investigations into this stranding and published the findings here. Again, iwi (Ngatiwai) are boning these animals out; this is called 'recovery', with the bones and oil being used for traditional spritual and cultural purposes.

Emma has recently returned from another mass stranding, at the top of South Island, and found extreme ulceration in the stomachs of a number of whales. Ulcers generally are caused by bad diet, (and in our case) smoking or drinking. I don't believe that these recently stranded whales smoke or drank! I'll start up a separate thread to discuss this shortly. I am sure that there will be some interesting debate as a consequence.

 

[monty]

It might be a good idea to culture for bacteria as well, it got these guys the Nobel Prize...