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October 2015    Download the Entire Issue (PDF) Available to the Public Vol. 41, No. 10   RSS Feed for Undercurrent Issues
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Is Your Camera Hurting Marine Life?

the effect of strobe and flash lighting on animals

from the October, 2015 issue of Undercurrent   Subscribe Now

A recent article of mine in Undercurrent about photographing seahorses ("The Fight to Stop Seahorse Photography" in the November 2013 issue) debated the effect strobes have on them. Despite my reference to the research work of David Harasti in that article, about how flash photography has no long-term effects on seahorses, I received a protest from one reader that a photographer's flash will stress and kill them.

All wild animals are paranoid. They are continually stressed. You only have to watch a bird or a squirrel feeding in your garden to be aware of this. Constantly facing the possibility of attack by a predator, wild animals are always alert and ready for flight.

When I was an advertising photographer, I photographed animals, from cats to chickens and chimpanzees. All needed time to become accustomed to the new surroundings of the studio or special location in which they found themselves, but once they did, they seemed to ignore the huge output of light from the strong flash commonly used in a studio. Thanks to the technology available at the time, I needed around a thousand times more flash output than is produced today by a typical underwater flashgun or strobe.

Animals with quick responses see the flash as a slow pulse of light. Most animals have quicker responses than we do. For example, a saltwater crocodile has a reaction time 60 times faster than ours. It may be disturbed by you, but it certainly isn't startled!

A saltwater crocodile, with a reaction time 60 times faster than humans, may be disturbed by you but it certainly isn't startled.

Approaching a wild animal underwater, we are both intruders and possible predators. However, in the marine world, we are so far removed from what animals are expecting that they usually tend to ignore us unless we get too close. We are simply big, dark shapes vibrating with noise as we breathe. My experiments with bubble-free rebreathers tell me that it is our noise and our movement of which animals are wary. We are not invisible, but keeping as still as a rock and making no sound will give you the best chance of having a skittish scalloped hammerhead shark coming close.

So what happens when we take photographs? First, to be closely approached by a huge dark shape will alarm any smaller creature. There seems to be a rule under water that size matters. Small animals are eaten by larger ones. It's a war zone. Everything is eating everything else, or at least trying to. A big dark animal is a threat. A well-known marine wildlife photographer based in the U.S. is famous for his yellow wetsuits. They may look garish on the aft deck of the boat, but he believes they are less disturbing for the animals he photographs.

Each animal has a strategy for survival, so your very presence will be alarming, and it will take time for an animal to forget about your sudden arrival. The seahorse will turn its back, and the turtle may swim off in a hurry. Luckily, most marine animals have a short attention span, so if you stay still long enough, they will eventually ignore you. Of course, a large number of these dark shapes, all moving in different ways, will be exponentially more alarming. Large numbers of divers crowding round a single hairy frogfish must be very frightening for it. It frightens me!

When you approach closely with a camera, its big eye looks down at the creature. All animals are tuned to know when they are being looked at, which is why hunters wear masks. It is disturbing for them to be watched, but if they are not equipped for a high-speed escape, like, for example, a jack, they stay put and soon get used to the fact that they haven't been eaten. When the camera is fired, it makes a noise, and there is a pulse of light from the flash. (To put things in context, the pulse of light from a typical underwater flash is probably equal to one-thousandth the amount of light I used to photograph animals in the studio -- 20 joules of light as opposed to 20,000.)

As my next witness, may I introduce the octopus? It is an intelligent mollusc with a variety of strategies when threatened by a possible predator, including camouflage, diversion by way of an ink cloud, and finally flight. It also has a complex eye, which I suspect allows it to see well what happens when the camera is fired. I use a big camera, and at the moment the eye of the lens opens and shuts, there is a loud clatter as the mirror mechanism works, and the flash emits a pulse of light. Under these circumstances, the octopus usually appears to flinch, clearly indicating that it is disturbed. But what is actually disturbing it?

My experience leads me to believe that the octopus reacts first to the close approach of a large dark object (my body), and second to the vibration of the camera mechanism operating. However, after a few moments, the animal either settles down and decides there is no threat, or it will flee. I have spent more than 45 minutes with two octopuses that were courting, and my noisy camera, dark body and light-emitting flashgun had no obvious effect on the course of events. I was able to take hundreds of close-focus wide-angle pictures of the whole procedure, from beginning to end. Similarly, I have spent long periods with turtles that have simply got used to my presence and allowed me to take multiple flash exposures from very close indeed.

It may be different if you have a constant light source shining in their eyes, as when shooting video. If an animal decides it is not under threat of predation, it will tolerate you. Of course, an animal that is nocturnal will not enjoy being lit up by a bright light. Fitting a red filter over the flashgun when photographing animals at night appears to mitigate this problem. Some continuous light sources come with a red light function, too. The pulse of light from a flash is either too slow to disturb those animals with very quick responses or, I suspect, with lower life forms, too quick to evoke any response at all.

It's annoying that when you line up a camera on a macro subject such as a pygmy seahorse, or any seahorse for that matter, it tends to turn away shyly. This is because predators detect the presence of prey often by the existence of its eye. Many coral-browsers have developed a defense strategy of displaying a false eye on a less vulnerable part of their body. The eyes of the seahorse must be kept hidden when the animal feels threatened -- but don't think it only does this to photographers.

So do we stress the animals? The immediate answer is, yes. Just as the marauding jack stresses the anthias, fish stress the browsing octopus and the white-tip reef shark stresses the little fish hiding among the rocks at night. So all divers stress the animals by our sudden arrival. Slow movements and plenty of patience go a long way to getting good pictures. Fish are not frightened by big rocks, and I have noticed that a still group of divers huddled together in an area of sandy seabed, testing regulators, for example, can actually attract some sedentary predators, such as frogfish, which see the black shape as a useful dark place to hide.

So does the camera's flash disturb animals? I have serious doubts. My point is that fish are very aware of a diver's presence. The fact that divers themselves may alter fish behavior is in tune with the study described on page 20, which clearly finds that to be the case. It's not just the flash of the strobe they notice, it's the very presence of these enormous beings.

John Bantin is the former technical editor of DIVER magazine in the United Kingdom. For 20 years, he used and reviewed virtually every piece of equipment available in the U.K. and the U.S., and made around 300 dives per year for that purpose. He is also a professional underwater photographer, and most recently the author of Shark Bytes, available at

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