Damage to marine animals eyes by strobes.

Subject: Likelihood of Damage to marine animals eyes by use of strobes.

I've written an article about this based on my own long experience photographing animals with up to 40,000joules of strobe. (A typical underwater strobe delivers a lot less than 100joules).

I also got the opinion from a distinguished professor in animal welfare - but he is my brother!

My editor would like to add the opinion of some independent marine biologist that has made a proper study (with a control group) of this. Do any of you know of such a study or such a marine biologist?

Thanks.

No, but I have witnessed a hippocampus Denise that, after a photographic onslaught, was so stunned that it literally fell off the fan it was on and was unable to swim back to it. I tried to guide it to a safe place in the hopes that it would recover.

Well John, I think only you would have the audacity as to handle this subject in print, in some definitive form, when research has shown that certain fish farms and industries use strobic light to control (as in keep away) fish. I'd say the definitive answer is somewhere in the middle, especially with just the anecdotal evidence available. It'll be interesting how you write that piece.

I'm sure you remember these threads with some information:

http://wetpixel.com/forums/index.php?showtopic=31049

http://wetpixel.com/forums/index.php?showtopic=27940

Well John, I think only you would have the audacity as to handle this subject in print, in some definitive form, when research has shown that certain fish farms and industries use strobic light to control (as in keep away) fish. I'd say the definitive answer is somewhere in the middle, especially with just the anecdotal evidence available. It'll be interesting how you write that piece.

 

I'm sure you remember these threads with some information:

 

http://wetpixel.com/forums/index.php?showtopic=31049

 

http://wetpixel.com/forums/index.php?showtopic=27940

Thanks Drew.

Can you point me in the direction of this research?

My brother is a professor of animal care and welfare at Shanghai Agricultural University. He is not aware of any research on the subject. Who would fund it?

The thrust of my article is that it's not the flash but what's attached to it (the person) that does the damage! If you are worried about the fish - get out of the water.

My own experience subjecting animals to pulses of light in the order or 20,000 - 40,000joules in controlled conditions during the eighties was limited to cats, dogs, rodents, chickens, ducks, chameleons, toucans, parrots, horses, snakes, tortoises, chimpanzees and (most like pigmy seahorses) head-lice. My experience underwater is only anecdotal.

John, are you referring to the brightness of the strobe or the pulsating effect?

I was recently diving with lemon sharks in the Bahamas (see Steve for more details), I decided to try and place my new (inexpensive) 1200 lumen torch in the sand pointing up for an effect on the sharks as they swam low, unfortunately the torch started to flood and responded with a strobing effect, flickering for ages, the sharks were immediately attracted to this as if it was food, there must have been about 4-5 trying to pick the torch up at once, so as regards to sharks, my answer would be that they like it, (quite the opposite of when I started a thread on this about Emperor stopping me using my strobe in June 2008 on OWTs)

A researcher at the School of Ocean Science in Bangor (North Wales) did carry out some research on flash illumination and the Lesser Octopus some years back, but whilst I remember talking to her about it, I have no details of the actual research nor whether it was just a part of a bigger research project.

No, but I have witnessed a hippocampus Denise that, after a photographic onslaught, was so stunned that it literally fell off the fan it was on and was unable to swim back to it. I tried to guide it to a safe place in the hopes that it would recover.

On the other side, I have witnessed Hippocampus denise that continue to feed constantly as photographers shoot (but I've also seen them flee fans).

A researcher at the School of Ocean Science in Bangor (North Wales) did carry out some research on flash illumination and the Lesser Octopus some years back, but whilst I remember talking to her about it, I have no details of the actual research nor whether it was just a part of a bigger research project.

Thanks Paul. My own (not scientific of course) research is with mating octopus. In a period of 45 minutes I fired my flash at close quarters 231 times without putting them off their stroke! I found the same with feeding turtles (and dugong). It's a question of priorities. I could certainly make a head lice fall off a hair with a pulse of light but I'm not sure if it was the light or some other effect. (Actually head lice are much more interesting to look at than pigmy seahorse!)

John, are you referring to the brightness of the strobe or the pulsating effect?

I was recently diving with lemon sharks in the Bahamas (see Steve for more details), I decided to try and place my new (inexpensive) 1200 lumen torch in the sand pointing up for an effect on the sharks as they swam low, unfortunately the torch started to flood and responded with a strobing effect, flickering for ages, the sharks were immediately attracted to this as if it was food, there must have been about 4-5 trying to pick the torch up at once, so as regards to sharks, my answer would be that they like it, (quite the opposite of when I started a thread on this about Emperor stopping me using my strobe in June 2008 on OWTs)

My article was stimulated by your post of 2008 and an request for an opinion from the boss of Emperor. It has only just surfaced as a feature!

My article was stimulated by your post of 2008 and an request for an opinion from the boss of Emperor. It has only just surfaced as a feature!

Thanks John, I dont think theres not much more to say on that event other than what I said originally, but if you need anything just let me know....sorry I believe it was 2009, my mistake

Thanks Drew.

 

Can you point me in the direction of this research?

 

My brother is a professor of animal care and welfare at Shanghai Agricultural University. He is not aware of any research on the subject. Who would fund it?

 

The thrust of my article is that it's not the flash but what's attached to it (the person) that does the damage! If you are worried about the fish - get out of the water.

 

My own experience subjecting animals to pulses of light in the order or 20,000 - 40,000joules in controlled conditions during the eighties was limited to cats, dogs, rodents, chickens, ducks, chameleons, toucans, parrots, horses, snakes, tortoises, chimpanzees and (most like pigmy seahorses) head-lice. My experience underwater is only anecdotal.

John, your views on this are very clear.

I don't agree totally with it but then again, it's all anecdotal evidence. I can't remember the names of the researchers but I did read a few studies that were done at the behest of power companies like Socal Edison, who wanted ways to keep fish away from the water intakes etc. I do remember the study doesn't really fit your article as they used strobic lights with high frequency (60-120fpm) Results were mixed with some finish turning around and one species was even attracted to the strobing lights. Like you, I wanted a definitive answer and the research I read didn't give me one. Like I said, the answer is somewhere in the middle and can't necessarily be clearly defined as a yes or no thing.

I even remember reading a study about how one test species avoided strobic lights more as the turbidity of the water increased! I discussed this with a few marine biologists and they postulated that some fish hang around because the lights attract invert prey species and thus they hunted in the light, while maintaining their distance.

An interesting topic.

If you find any research you may also want to consider the difference between constant pulses (as in a strobe we may place on a mooring line on a night dive) and irregular pulses as in a camera strobe; Thinking about the sharks they must have been attracted to the flooded torch as they thought it was distress signals from prey, how would this differ if the pulses were regular/irregular, if at all? And same for the water intake pipes?

On the other side i have seen a turtle swim headlong at speed into a rock after a strobe was fired in his/her face on a night dive, so surely there must be some reprecutions...

Olly

Sounds like you guys are discussing two different things here; reaction to light of various species, and damage ( I imagine you mean something that is more than just temporary) to their eyes. Clearly many animals react to light flashes, pulses etc, but that's not the same as damage to the eyes. Even being temporarily blinded, as even humans can be is not the same as suffering damage to the eyes. So probably without pathological evidence to the contrary this would be impossible to prove and at best light pulses etc could be considered harassment. I think the article would have to reflect this distinction to make any sense.

From memory when I discussed the lesser octopus (Eledone cirrhosa) with the researcher working on this species she said that being subjected to repeated (not pulsed) fairly high intensity flashes (when in relatively dark conditions) could lead to the creature going into 'shock'. She suspected that continued exposure to strong flashes might actually have led to death (ultimate damage?). So flashes can have an effect far beyond merely causing them to react. Having said this, my experience is that even Eledone fails to react to flash if its in bright conditions such as brightly sunlit shallow water, so its clearly not as simple as being just the flashes of light themselves. Another creature which I have been told can have adverse reaction to flashes is the Dublin Bay Prawn (Nephrops norvegicus), and I've seen aquarium exhibited creatures kept in barely lit tanks with 'NO Flash Photography' signs around them too - although it has to be said that millions of these animals are trawled up each year with scant regard for their vision when they are hauled up into daylight!

Very true, Jeff. Thanks for the clarification. To further that, what about temporary blindness leading to being less aware of predators leading to being easier prey? Or early onset of cataracts (do strobes have high UV output? )

Very true, Jeff. Thanks for the clarification. To further that, what about temporary blindness leading to being less aware of predators leading to being easier prey? Or early onset of cataracts (do strobes have high UV output? )

Well, I guess it's not as bad as those video lights.

After strobing it a dozen times, I was horrified to see a H.Pontohi just fall from its perch. I caught it in my open palm and my guide helped it back to where it came from. I was worried I'd killed it and stayed to watch it out of curiosity for ten minutes. It wasn't dead and eventually started moving about, but I decided there and then that I wouldn't do that again. When I told the resort's dive manager he replied "Don't worry Will, they're like ants" (!!!) H. bargibanti sometimes 'quiver' after a flash. I limit my shots and turn down the power with these little guys. On the other hand some critters seem to love it - squid, trumpetfish and barracuda come to mind.

Personally I cannot see (excuse the pun) how it wouldn't effect the subject, especially those used to a darker environment, it must be a bit of a shock to be flashed once if you are not expecting it let alone an onslaught of flashes... If scientific study concludes that flashing 'high powered lights' into the eyes of your subjects causes stress or worse will the shooters cease to use them???

Dive safe

DeanB

Then there's a discussion of does stress constitute damage, or again just harassment. Probably stress is more important from a practical standpoint. John, the issue of strobes and manatees is a current issue that may be important for your article

Then there's a discussion of does stress constitute damage, or again just harassment. Probably stress is more important from a practical standpoint. John, the issue of strobes and manatees is a current issue that may be important for your article

When it comes to Manatees, from what I've heard about diver behaviour, I believe that man's inhumanity to man at the site might be more relevant!