A few months ago, on April 4, 2019, Reef2Reef published an article called "Depression in Fish". Although the article was well researched, and I personally fact-checked it, we received from our readers a lot of pushback to the article's premise that, yes, fish can and do suffer from depression.

So, when I was fortunate enough to talk to Dr. Culum Brown recently, the first question I asked him was about depression in fish.

Yes, fish can and do suffer from depression. "Their physiology is very similar to our own. Antidepressants work on fish in the same way as they do in humans," he said.

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Dr. Culum Brown is Professor in the Department of Biological Sciences at Macquarie University in Sydney, Australia. He's one of the world's leading experts on fish behaviour and cognition and the co-editor and major contributor to many of the chapters of the textbook, Fish Cognition and Behaviour, a book that I have and am planning to review for Reef2Reef in the future.

He's also Editor of The Journal of Fish Biology, and he runs the "Fish Lab," the Behaviour, Ecology and Evolution of Fishes Laboratory that is part of Macquarie University and which conducts research on freshwater and saltwater fishes.

According to his website, he got his Ph.D. at University of Queensland and did post-doc training at both Cambridge and then University of Edinburgh and in collaboration with the Smithsonian Research Institute in Panama. If you need any further convincing of his credentials, then have a look at his Google Citations page for publication details.

Research at the Fish Lab includes the following: "movement and migrations of Port Jackson sharks, social behaviour of reef manta rays, spatial learning in intertidal gobies, and pain perception and sentience in fish." This information was taken from the Research page of their website.

I asked Dr. Brown a series of questions, and I'm going to let him speak for himself here and quote him directly. Direct quotes are in italics and in blue for ease of reading.

A Manta ray.
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Photo is courtesy of @Seawitch ©2019, All Rights Reserved.

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I asked him about the research related to Port Jackson sharks that his lab is working on:

Our PJ research is very varied. We started out by just trying to figure out where they go. Acoustic tracking is a fab way to do that. We can also figure out if there are any environmental variables that drive their movements. But there is heaps of other information you can get from these tags including detailed information about who they hang out with. So we have a pretty good understanding of their social lives as well.

The fish lab, like most research centers, needs press and money. They have one program where you can donate a certain amount and adopt a Port Jackson shark and name him or her and follow his or her movements. But there are also other programs that you can support if you feel so inclined.

We have several projects that rely on crowdfunding, one on smooth stingrays (the biggest marine stingrays in the world), one looking at the movement and behaviour of manta rays, and, of course, the PJ work. Supporting this work with donations of any size is always highly appreciated. And people can buy our lab t-shirts (we don't actually make money on those, but it spreads the word).

A Port Jackson shark, Heterodontus portusjacksoni.
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Photo is courtesy of Richard Ling from flickr and used with permission via Creative Commons License 2.0.

I noticed on one of the Fish Lab web pages that there was a grad student studying zebrafinches. I asked Dr. Brown about that because I wondered if that was a fish I hadn't heard of.

Yes, Larissa is one of my few non-fishy students. I've worked on bats and parrots, even mosquitoes before. You'll be pleased to know that her honours work was with fish.

Then I asked about what was new and exciting in fish behaviour research.

Most of our work tries to change public perception of fish behaviour. We are trying to get people to realize that they are pretty sophisticated animals and as such we really ought to treat them better than we currently do. We spend a lot of time talking about how smart fish are and what implications that has for animal welfare and ethics more broadly.

I asked him about quarantine because that's such an important and hotly-debated topic among aquarists.

Yes, if we do freshwater work, then all of our tanks are completely isolated, although we do have some flow-through systems for high-density work with guppies.

Our marine system is separated into 6 different systems, so, if we work with animals from different locations they can be put into different systems. Quarantine is generally not such a big issue when working with marine critters given the high degree of connectivity in that environment.

We tend to source most of our animals from the wild and for the most part they are always healthy. It would be very unusual for us to deliberately sample an unhealthy animal. But when we work with larger sharks we often give them a brief freshwater bath to remove parasites. Where possible, I steer clear of medical treatments simply because that stuff just ends up in our waterways and has all sorts of nasty implications.


What can we—the aquarist population—do to raise awareness about the consciousness of fish? That they’re smarter than we think, and that they can feel pain and depression?

As I suggested previously, fish are way smarter than most people realize, and this has ethical implications. For the most part their brains and physiology are very similar to our own. Our pain receptors, for example, come from our fishy ancestors. They have similar hormones and receptors so their psychology is also similar to ours. They get scared and anxious and depressed just as we do. As aquarists the best you can do is to look after your animals as best you can. We really need to dispel the notion that fish are just ornamental. They are pets like cats and dogs and deserve more attention.

I asked him what he thought about marine aquarists trying to breed fish at home.

I've been breeding my own fish since I was a little kid and trading them for supplies. We should not be taking fish from the wild if at all possible. So I strongly encourage folks to learn about their fish and breed them at home. To me this was always one of the most exciting parts of keeping fish. If they breed then you must be doing something right!

One of the biggest challenges breeding fish is getting the fry to juvenile stage. Let's keep in mind that in the wild the vast majority of babies just don't make it. The key is providing the right food at the right stage. Sadly, some fry just never start to feed once their yolk sac is depleted. It's a key developmental hurdle. I used to spend more time growing live cultures than I did looking after my fish. It's hard work, but I found it rewarding.

Some of the research at the Fish Lab has been on studying the learning of life skills for hatchery-raised fish. Even though there are many programs world-wide attempting to replenish wild fish stocks with hatchery-raised fish, "97% of all hatchery-reared fish die before adulthood," according to Dr. Brown's website.

Then, I asked him about what aquarists can or should do with captive reef systems to make the fish’s life more interesting or mentally challenging.

I think it is important to keep your fish stimulated. Live food, a well planted (complex) aquarium, and the appropriate community is a very good start. I often move things around a little from time to time to make things interesting. Some fish will just move stuff back again, but it keeps them busy!

I asked if there was anything in particular that he hasn't studied yet but is thinking about and would like to in the near future.

There are sooo many things on my to-do list. Every time I go diving I come back with a head full of questions. The other day I was watching a trigger fish moving huge clumps of coral to get at invertebrate prey underneath. There was a stack of other fishes following it around hoping for some scraps. So many questions stem from that one observation. Nature provides me with enough inspiration to keep me going for ever.

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Photo is courtesy of @Seawitch ©2019, All Rights Reserved.

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Since talking with Dr. Brown, I've been thinking about Dr. Temple Grandin, the animal behaviourist at Colorado State University, who has spent most of her life fighting for more humane treatment of livestock headed for slaughter.

To be clear, in an interview with The Dodo, Dr. Brown says that he is not opposed to "fishing or eating meat." What he wants is to change the public perception of the intelligence of fish and to minimize their stress and pain as much as possible, and this is what Dr. Brown considers his life's work.

He wants us to have empathy for fish because they are sentient creatures. This concept of fish being thinking, feeling creatures, each with his or her own personality not unlike cats or dogs is a major paradigm shift for the public.

There's no doubt that some of the reading audience may not agree with these research findings, and some may be uncomfortable with it. That doesn't make the science less true.

In the 1980's, Australian medical doctor, Barry Marshall, had a tough time convincing the medical community that stomach ulcers were caused by bacteria. He won the Nobel Prize in 2005 for his discovery.

Gregor Mendel (1822-1884), considered the father of modern genetics, was dismissed as a nut-bar during his lifetime. His theories did not come to be accepted until the early 20th century.

The German philosopher, Arthur Schopenhauer said, "All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident."

Here is a videotaped interview with Dr. Brown, if you would like to learn more about fish cognition.


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Reef2Reef is grateful to Dr. Brown for taking some time out of his busy schedule to talk to us. We hope to bring you more news from the Fish Lab at Macquarie University in the future.

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References:

https://sites.google.com/site/culumbrown/life-skills-for-hatchery-fishes

https://www.thedodo.com/toward-a-new-fish-consciousnes-601531647.html

https://link.springer.com/article/10.1007/s10071-018-1225-8

https://animalstudiesrepository.org/cgi/viewcontent.cgi?article=1375&context=animsent

https://animalstudiesrepository.org/cgi/viewcontent.cgi?article=1317&context=animsent

Byrnes, Evan & Brown, Culum. (2016). Individual personality differences in Port Jackson sharks Heterodontus portusjacksoni. Journal of fish biology. 89. 10.1111/jfb.12993.

Vila Pouca, Catarina & Brown, Culum. (2018). Fish - How to ask them the right questions. 10.1017/9781108333191.011.

http://thefishlab.com/research.html

https://www.medscape.com/features/slideshow/medical-breakthroughs#page=6

https://www.medicaldaily.com/mad-scientist-6-scientists-who-were-dismissed-crazy-only-be-proven-right-years-later-362010

Brown, C. (2015) Fish intelligence, sentience and ethics. Animal Cognition 18, 1-17

https://evolution.berkeley.edu/evolibrary/article/0_0_0/history_13

https://www.nobelprize.org/prizes/medicine/2005/marshall/facts/

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Editor Profile: Cynthia White

Cynthia received her BA in English from NYU a long long time ago. She has been a freelance writer and editor for over 20 years. Now she is a writer and editor on staff at R2R, where her forum nickname is @Seawitch.