RYAN NEVATTE

Me examining a Common Sawshark embryo (Photo credit: An Grobler)

When most people think of "sharks," they usually picture a great white shark leaping out of the waves and crashing back down under with a seal in its mouth.
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They usually do not picture the two animals that scientist Ryan Nevatte studies: the Common Sawshark (Pristiophorus cirratus) and the Southern Sawshark (Pristiophorus nudipinnis). 

With a spade-like nose with long tendrils on either side, they look like a mash-up of multiple animals together instead of an actual living animal. But it's true, sawsharks are a thing! We know little about them and scientists like Ryan are beginning to uncover their mysterious lives.

TFUI is very excited to have Ryan here to discuss his work for the Behind the Fins series!

The Fins United Initiative: What got you interested in marine biology?
Ryan Nevatte: I think I developed an interest in marine biology from an early age because of the Disney film “The Little Mermaid”. I used to watch that movie over and over again as a kid. For some reason, the underwater world showcased in the movie really appealed to me. Maybe it was the great music and stunning animation? Whatever the reason, the fascination with marine life has stayed with me.

TFUI: And what about sharks?
RN: My particular interest in sharks, I think, developed from trips to the aquarium and seeing these animals for real. There was just something about them. It led to me collecting and reading many different books on sharks. For my 7th birthday, I asked for a documentary that the Discovery Channel had just released on video called “The Ultimate Guide to Sharks”, and I would watch that video a lot. So, I think the path to studying marine biology and sharks was laid down pretty early.

TFUI: If not marine biology, what other field interests you?
​RN: That’s a tricky question. I think that biology in general is pretty amazing because there are so many interesting things you can learn and often these things come from different disciplines, such as anatomy, behaviour or genetics. If I had to pick one, I would say palaeontology because who doesn’t like dinosaurs? Related to that, I also quite like ancient history.   

Common Sawshark embryos (Photo credit: An Grobler)

TFUI: What are you currently studying right now? 
RN: For my PhD, I am studying the population genetics of sawsharks in the waters of southern Australia. So, essentially what I’m interested in is determining whether genetically distinct populations of sawshark occur in Australia. The two species I work on are the Common Sawshark (Pristiophorus cirratus) and the Southern Sawshark (Pristiophorus nudipinnis).

TFUI: We don't hear about sawsharks that often! 
RN: You’re right! We don’t hear about sawsharks all that often and when you mention them to people they tend to think of the sawfishes they might have seen at the aquarium. While sawfish are very cool and look similar to sawsharks, the two animals are not the same. Sawfish are actually a type of ray, whereas sawsharks are true sharks and you can tell this by looking at where on the body the gills slits are located. The gill slits of sawfish are on the ventral surface (underside) while sawsharks have them on the side of their body, like other sharks. Sawsharks are also rather unique in that they possess these long, whisker-like structures called barbels that hang down from their rostrum (the saw), which sawfish don’t have.

TFUI: What are some other differences?
​RN: Other differences include their body sizes (sawfish can grow to about 7 metres while sawsharks only reach 1.5 metres) and the sizes of their rostral teeth (sawfish have rostral teeth of the same size along the rostrum whereas sawsharks have alternating small and large teeth).  
One of the things that makes sawsharks so special is their mystery. We currently know very little about their biology. This is largely due to sawsharks living in the deep waters of the continental shelves and slopes (down to 1000 metres), which makes it difficult for us to obtain specimens and observe them in the wild. There are currently 8 recognised species of sawshark in the world; 3 of which were only described in the last decade!

TFUI: So what makes them so special?
RN: Apart from being really cool and unusual, the main reason why we should learn more about sawsharks is to ensure that these sharks are harvested sustainably. Here in Australia, the two sawshark species I work on are frequent by-catch in several commercial fisheries and the meat from these catches is sold for human consumption (i.e. fish and chips). It has been estimated that 300 tonnes of sawshark has a value of over $2 million (AUS); so even though their capture is unintended, sawsharks are an additional form of revenue for fisheries.

TFUI: Why should we learn more about sawsharks? 
RN: In the case of my research, knowing whether Common and Southern Sawsharks comprise of a single, large, connected population or lots of small, isolated populations will help with management plans. At the moment, both species are considered to be harvested sustainably but this doesn’t take into consideration population structure (because we don’t know it). Harvesting without sufficient knowledge of population structure can result in the depletion of resources and loss of genetic diversity. So, by adding this extra layer of information to current management plans, the management of sawsharks will become more effective.

Common Sawsharks (Photo credit: Ryan Nevatte) – The blue cable tie and paper attached to the saw I used to identify individuals when collecting measurements and tissue samples.

TFUI: So what is one thing that we can’t find you without?
RN: In my office at uni, that would be my Scooby Doo mug. It would have either coffee or tea in it depending on the time of the day.

TFUI: Do you think people in your region have a good relationship with the elasmobranchs? If not, what can be done to better it?
RN: Generally, I would say yes. Even if someone is not particularly fond of sharks, they can still understand the importance of sharks to the marine ecosystem. However, fear seems to be a very common emotion or response when it comes to sharks and it can become heightened when several incidents involving sharks occur in a relatively short space of time. I think that the language used by the media can create the wrong impression and add to this fear. Really, we need to respect sharks not fear them and this could be achieved by the media choosing their words carefully and scientists getting the facts out to the public.
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TFUI: What has been the coolest part of your research findings so far?
RN: The coolest thing that I have found so far is that population structure seems to be different between the two species of sawshark. One species seems to consist of two distinct populations whereas the other species seems to consist of only one. The low number of distinct populations we observe also implies that populations of both sawshark species are highly connected. This means that individuals from different parts of Australia are able to move freely from one population to another and reproduce with members of those other populations. If they weren’t able to, we would expect to see many distinct populations. This challenges the long-held idea that sawsharks don’t travel very far.

Me (left) and Patrick Burke (right) collecting a fin clip from a Southern Sawshark in the BBQ hut (Photo credit: Jane Williamson)

TFUI: What has been the neatest experience out in the field/lab?
RN: An experience I had on a recent field trip springs to mind. It wasn’t exactly neat but it was definitely memorable. A few of us from our lab were collecting samples for different projects down the south coast of Australia, one of which was my sawshark work. We had just picked up some boxes of sawsharks from a local fish cooperative and driven to our accommodation in a small fishing village in Victoria. It was the middle of winter so it got dark and cold very quickly and I needed to collect tissue samples and measurements from the sharks as soon as possible. The problem was that these sharks had been snap frozen and were all stuck together. I also didn’t have any suitable facilities for processing the sharks, so had to make do with a small BBQ hut just outside the house.

TFUI: Okay, go on...
RN: So, on a freezing cold night, my lab mates and I were carrying kettles and saucepans of boiling water from the house to the hut and pouring them into the boxes to defrost the sharks. It worked really well but if anyone else had been watching, it would have looked completely mad. Then came the measuring and tissue collection. The hut had a single light that was on a timer and controlled by a push button. The timer never seemed to last very long and always went out at the most inopportune moment, such as when I was about to read out a measurement or cut out a tissue sample. It took us a while but we managed to finish 8 sharks that night. The others we were able to do the next morning. We still laugh about the whole situation. The things you do for science, eh?

TFUI: What’s a myth about being a shark researcher that you want to clear the record about?
​RN: I guess people might think that shark researchers or anybody studying marine biology spend all their time out on nice, white sandy beaches and frolic around in the water all day. While fieldwork is great, and can often take us to some amazing places, this is only a small part of what we do. Being a researcher involves doing many different things such as reading and writing papers, conducting experiments and analysing data. This can often mean spending long hours in front of a computer or in the lab. The work can be tough, but it is ultimately rewarding. A shark researcher is not just someone who loves sharks (although that is always a plus), it is also someone who loves science and the discoveries that are made possible by the simple act of asking a question. 

The makeshift lab in Victoria (the BBQ hut is on the right) (Photo credit: Lou Tosetto)

TFUI: What’s next for you? Where do you see yourself and your career in five years?
RN: Well, the first thing would be to finish my PhD. From there, I think I would like to continue researching sawsharks (maybe as a post-doc) because they are such an unusual group of sharks and there are still many things about them that we just don’t know.

TFUI: If 2019 could change one thing for sharks, what would you hope it would be?
RN: That the general perception of sharks in people’s minds changes from fear to respect. Plans for conserving something that is respected are going to be far easier for people to get behind than for something that is feared. 

TFUI: Who’s inspired you most in your marine science career?
RN: Definitely my parents. They have always encouraged me to try my best and follow my interests and supported me all the way. 

THE FINS UNITED INITIATIVE WOULD LIKE TO THANK ryan FOR His TIME AND 
WE WISH Him WELL ON His CURRENT/FUTURE PROJECTS! 

SAY HELLO!

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