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Using dimethyl sulfide as chum (1 Viewer)

Odonate

Well-known member
Hi all

I take a group of my second year Biological Sciences students from Plymouth University to the Azores every September (it just about makes up for the rest of the year!). Hard job but someone has to do it. With a later flight time this year we have an extra half a day and want to take them "Whale Watching" (read, I want to do a pelagic). To make some sense of the exercise and to put some science into it, I wanted to do something on olfactory cues in food searching in seabirds. I thought it was pretty well accepted that seabirds follow miniscule amounts of DMS (dimethyl sulfide) to tell them where the algae and thus other food, might be. However, while I find a lot of newspaper type articles on this, I cant find any reports of the use of DMS at sea (I'd need to know a conc/carrier etc).
Does anyone here have any idea if this has been tried and anywhere I might find some information?

Thanks

O
 

Xenospiza

Distracted
I don't know if it has been tried, but during my chemistry PhD I smelt the stuff. It is one of the worst smells I have ever witnessed (and I worked with many sulphur compounds): absolutely gag-reflex-inducingly horrendous! If you have ever smelt mountains of rotting sea weed: that comes close. Better stick to rotting fish innards... which probably release DMS anyway!

Taking it on a plane is ill-advised. Its boiling point is 37 °C so you can imagine how hard it is to contain. While handling it, you'd also have to wear some good gloves to avoid spilling it on yourself: you will not get rid of the smell quickly... The only bit of good news is that it is not all that poisonous!
 

Nutcracker

Stop Brexit!
Yes, it has been tried; but (as its powerful stench hints!) you only want to use a tiny drop diluted a huge amount in the chum!

Smells inbetween sewer gas and rotten eggs.
 

Odonate

Well-known member
Thanks both. I did eventually find a couple of references. Both use 0.2 mol/L which seems incredibly high to me. I may have to stick to fish instead.
 

Farnboro John

Well-known member
I'm sure this has been discussed before but isn't there a moral question about using DMS, thereby implying a level of reward via the smell that is not borne out by the chum.... the smell of fish guts/oil/maize by contrast is proportionate to the reward obtained.

John
 

rdcny

Well-known member
I have no problem with you using lures to bring in birds for students to see. They (students) are much more likely to become interested in, protect and want to know more about the species they can see/experience directly. As an aside, I use recorded calls all the time to bring in birds to show people on my bird walks in Central Park. Can anyone find a scientific study that shows using such lures (whether audio or olfactory) harm birds? Using lures changes their behavior for a short period of time...On the other hand, the positives in terms of education, are obvious to anyone who works with people eager to learn. Robert DeCandido PhD
 
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Farnboro John

Well-known member
I have no problem with you using lures to bring in birds for students to see. They (students) are much more likely to become interested in, protect and want to know more about the species they can see/experience directly. As an aside, I use recorded calls all the time to bring in birds to show people on my bird walks in Central Park. Can anyone find a scientific study that shows using such lures (whether audio or olfactory) harm birds? Using lures changes their behavior for a short period of time...On the other hand, the positives in terms of education, are obvious to anyone who works with people eager to learn. Robert DeCandido PhD

As with most things biological, one size does not fit all. You've said it yourself: using lures of any kind means that birds do something they wouldn't otherwise have done. There is an opportunity cost to the birds associated with that deception: the obvious other side of the coin is that while they are doing that thing, they are not doing something else that they woulda, coulda and most likely shoulda done.

For the most part - e.g short time spent responding to song playback - the difference made to the bird's day is almost certainly insignificant, even if it is holding territory. Its energy expenditure consequent on the reaction is small: if it sings back to the recording it is at least continuing to advertise its domination of the territory. More or less, no harm, no foul.

Chumming, with suitable reward included, is not innately immoral. However, to deal seabirds living in a mostly empty ocean the level of smell that suggests they are closing on a dead whale and then provide them with a small-scale meal, causing them to expend energy in flying to the disappointing takeaway that could have been used in searching for a decent meal (or even misdirecting them away from one through the excessive chemical release) - that's another kettle of fish. And a fairly smelly one.

I'm not totally certain that the education argument is sufficient justification for that particular course of action.


John
 

rdcny

Well-known member
Can you show me one scientific study that supports your suppositions/suggestions that an olfactory lure is significantly harmful to seabirds? Otherwise I can construct equally interesting scenarios in which seabirds do just fine with an olfactory lure.

Education education, education - I put my money and ethics there.
====================
As with most things biological, one size does not fit all. You've said it yourself: using lures of any kind means that birds do something they wouldn't otherwise have done. There is an opportunity cost to the birds associated with that deception: the obvious other side of the coin is that while they are doing that thing, they are not doing something else that they woulda, coulda and most likely shoulda done.

For the most part - e.g short time spent responding to song playback - the difference made to the bird's day is almost certainly insignificant, even if it is holding territory. Its energy expenditure consequent on the reaction is small: if it sings back to the recording it is at least continuing to advertise its domination of the territory. More or less, no harm, no foul.

Chumming, with suitable reward included, is not innately immoral. However, to deal seabirds living in a mostly empty ocean the level of smell that suggests they are closing on a dead whale and then provide them with a small-scale meal, causing them to expend energy in flying to the disappointing takeaway that could have been used in searching for a decent meal (or even misdirecting them away from one through the excessive chemical release) - that's another kettle of fish. And a fairly smelly one.

I'm not totally certain that the education argument is sufficient justification for that particular course of action.

John
 

ClarkWGriswold

Carpe Carpum
Staff member
Supporter
Wales
Yes, it has been tried; but (as its powerful stench hints!) you only want to use a tiny drop diluted a huge amount in the chum!

Smells inbetween sewer gas and rotten eggs.
You'd have thought Port Talbot would have been overrun with Petrels, Shearwaters and Albatrosses :smoke::-O
 

Farnboro John

Well-known member
Can you show me one scientific study that supports your suppositions/suggestions that an olfactory lure is significantly harmful to seabirds? Otherwise I can construct equally interesting scenarios in which seabirds do just fine with an olfactory lure.

Education education, education - I put my money and ethics there.
====================
As with most things biological, one size does not fit all. You've said it yourself: using lures of any kind means that birds do something they wouldn't otherwise have done. There is an opportunity cost to the birds associated with that deception: the obvious other side of the coin is that while they are doing that thing, they are not doing something else that they woulda, coulda and most likely shoulda done.

For the most part - e.g short time spent responding to song playback - the difference made to the bird's day is almost certainly insignificant, even if it is holding territory. Its energy expenditure consequent on the reaction is small: if it sings back to the recording it is at least continuing to advertise its domination of the territory. More or less, no harm, no foul.

Chumming, with suitable reward included, is not innately immoral. However, to deal seabirds living in a mostly empty ocean the level of smell that suggests they are closing on a dead whale and then provide them with a small-scale meal, causing them to expend energy in flying to the disappointing takeaway that could have been used in searching for a decent meal (or even misdirecting them away from one through the excessive chemical release) - that's another kettle of fish. And a fairly smelly one.

I'm not totally certain that the education argument is sufficient justification for that particular course of action.

John

I think your disinclination to accept the argument is coming from the same place as the tobacco giants in respect of their products, frankly. It's simply not necessary to do a scientific study to evidence that if you provide a smell and no food, you cause harm to animals that are expending energy to investigate the scent, but if you provide food in proportion to released smell you don't: its in the realms of the perfectly obvious.

Sometimes the zeal of the evangelist needs to be checked by common sense.

John
 

rdcny

Well-known member
"Sometimes the zeal of the evangelist needs to be checked by common sense."

Yes I would say that end has been achieved. You cannot show me one shred of evidence to support your claim. Yes I understand what you are saying is reasonable - but you have zero evidence to support it...and zero evidence to show any harm has been done in the past using olfactory lures.

I try to navigate in my world via facts, verifiable information etc. You have not shown me facts...you have provided reasonable, possible explanations for what might happen. I can construct equally interesting explanations for good things that can occur by seabirds following olfactory lures.

Again, set in an educational context, I 110% support the use of olfactory and audio lures to bring in birds.

Robert DeCandido PhD
 

rdcny

Well-known member
"In contrast, the habituation we documented suggests that frequent, regular birdwatchers’ playback may have minor effects on wren behavior."

"...may have minor effects" = does not sound significant to me...

"It is possible that repeated short bouts of birdwatchers’ playback could lead to birds treating playback as normal neighbors, as was apparently the case in Ward and Schlossberg’s [19] long-term experiments."

 

RafaelMatias

Unknown member
Portugal
I have no strong position in one way or the other re usage or various lures to atract birds.

However, in the discussion section of the above cited paper the following is also stated:
Considering the above, irregular playback could potentially have a greater impact on bird behavior if individuals do not encounter playback often enough to habituate, and respond strongly in each instance of playback. On the other hand, if habituated birds show less pronounced responses, they might be less effective at defending their territories from true rivals [46]. These alternative hypotheses require further investigation.
and
Although our data show that bird behavior changes in response to playback, we did not measure the effects of playback on components of fitness such as survival or reproductive success.

and despite the final conclusion being:
Our results indicate that birdwatchers’ playback affects the vocal behavior of two species of Neotropical songbirds. This result suggests that playback could negatively affect species if they become stressed, expend energy, or take time away from other activities to respond to playback. By contrast, the habituation results we present suggest that frequent birdwatchers’ playback may have minimal impacts on wren behavior.

One must always remember that an absence of evidence is not evidence of absence.

Cheers
 

rdcny

Well-known member
What I read in this study is that the researchers found that playback changed behavior slightly...and not significantly.

I see this (note EMPHASIS mine): "Considering the above, irregular playback COULD potentially have a greater impact on bird behavior IF individuals do not encounter playback often enough to habituate, and respond strongly in each instance of playback. On the other hand, IF habituated birds show less pronounced responses, they MIGHT be less effective at defending their territories from true rivals [46]. These alternative hypotheses require further investigation." Lots of hedging bets...

and "This result suggests that playback COULD negatively affect species IF they become stressed, expend energy, or take time away from other activities to respond to playback." And others might interpret their data differently. In other words, they have no strong data to present that concludes anything except playback changed certain types of vocalizations of these wrens...and what negatives did they actually demonstrate other than their speculation that something MIGHT be a problem?
 

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