Unfortunately a tissue sample is needed in order to sequence the animal and bringing fish up from the deep sea does kill them :(. This is why I always proffer to send cameras down and record the fish where they live (they don’t get hurt and even get a free meal for posing for photos).
When a physical sample is needed, I do everything I can to make sure it is not a waist. I collect every possible sample and send them to colleagues all over the world. I also store spare samples just in case. If there is anything left, I use it for teaching. Because we have held on to lots of spare samples we probably have plenty already and your vote won’t hurt or kill an animal.
I hope that by catching just a few we can ensure that the whole species is safe. Teaching people about them and understanding what the fish need to survive will help us avoid doing anything that damages their population.
These fish aren’t rare but we would should still avoid causing distress to an animal and must respect the animals we work with. I hope that puts your mind at ease a little.
Hi! The simple but not complete answer is “it depends on the type of animal” – you need a tissue sample, but sometimes this can be just some blood or a small sample of the body. Some kinds of animals might not notice this!
However, when scientists work with DNA, they always make sure that they minimise harm to animals. Often we can work with animals that have been collected in the past, or that have been donated to us (by fishermen, for example). We have, for example, some naval shipworms that were collected several years ago. However, if we were to collect fresh animals, we can make sure the animal does not notice what happens, and treat them far better than they are treated in the wild!
I would have to hurt an animal a little bit, but not kill it. It should be enough cut a a piece of fin for example, but I would still need to hold and handle the fish including taking it out of water temporarily, which is quite stressful for fish.
With insects as small as twisted-wing flies, you need a specimen in order to extract enough DNA for sequencing. It’s very hard to know how much an insect suffers, but we always collect them in as humane a way as possible (ensuring they feel the minimum of pain or none), and never collect more specimens than we need to answer a particular question. Unfortunately there is no way of studying these microscopic creatures properly without having to kill them – one of the reasons is that different species can appear identical until preserved specimens are studied under the microscope. These specimens are preserved permanently in the Natural History Museum in London, and are made available for study for future generations of scientists.