Sebastián Kraft is living the dream. He works with the 'big animals' of marine biology - sharks and cetaceans. As he so nicely puts it on his twitter account (follow him @SebaKraft) - "Sharks are my main interest. Currently having a cetacean affair." We dig that. We also dig this interview, so you should dive on in and see what his work is all about!
The Fins United Initiative: So first, Sebastián, I have to know... why elasmobranchs?
Sebastián Kraft: I mean, just look at them, they’re objectively the most beautiful animals ever! And whoever tells you otherwise is either lying or oblivious. That is a scientific fact.
TFUI: I mean, we totally agree with you there.
SK: I’ve always had a fascination for fishes, especially sharks. My parents tell me that back in Germany (where I was born), they were at a flea market and saw a book called “Fisch ist Fisch”, which translates to “A fish is a fish”. The story features two friends, a fish and a tadpole. Eventually the tadpole starts to develop its limbs and ventures to land, coming back every now and then to tell the fish amazing stories of what he saw. The fish wanted to see all this so badly that he jumped onto land, only to find himself immediately gasping for air and dehydrating. The frog sees this and saves him and the fish then realizes he already lived in a beautiful place.
SK: From that point on I quickly got interested in sharks, or that’s what the drawings I made as a child tell me. I always liked their appearance, usually that’s what gets a kid’s attention first. I guess the same goes for dinosaurs, they too have that prehistoric, toothy look that fascinates many children. Elasmobranch’s eyes are also interesting. These might not be as communicative as ours, but I like how observant some of them appear to be, like they always know what’s going on. So eventually (also unsurprisingly), marine biology became my career of choice.
TFUI: Can you tell us a little bit about the work you are currently doing regarding molecular ecology?
SK: Broadly, what we do in our lab is answering ecological or evolutionary questions using DNA. There are two big groups of DNA, mitochondrial and nuclear. One of the reasons why we are all different is because DNA is variable, and that variability is not homogeneously distributed along its sequence. Some areas code for central components in certain tasks in your body (structural, functional, etc) and alterations in their sequence can lead to failure in embryonic development. Consequently, these regions are more conserved, and tend to accumulate mutations very slowly because during replication, the copies are thoroughly proof-read by the cell. Other regions accumulate variations faster because changes in their sequence are usually not as critical. The extreme case is that of non-coding regions that have no known function and were formerly called junk DNA.
TFUI: Tell us more!
SK: The right region(s) of the DNA strand that should be used will depend on the scope of your question (and sometimes the money you have). They are called molecular markers: one or more regions of the DNA of your choosing used to conduct the study. It’s somewhat like using the right instrument to measure a distance: a 50 cm ruler is fine to measure the size of a desk, but it’s not very useful to assess how far apart your house and your job are: there are other better suited tools (or molecular markers) to answer that. Slow-changing regions are useful for exploring ancient evolutionary relationships of distant entities, such as species, families and so on. Fast changing regions are used for ecological questions or recent evolutionary processes, like relationships among and/or within populations of the same species. For these type of questions, the D-loop is a very popular molecular marker, which is the most variable region in mitochondrial DNA. There might be differences in the DNA sequence between individuals, given by mutations, and these are called haplotypes.
TFUI: And what projects are you working on?
SK: I’m working on a few projects, but what takes up most of my time is my Master’s thesis. I seek to assess the genetic diversity and kinship in a mass stranding of 124 long-finned pilot whales using DNA. These dolphins were found on a very remote location in southern Chile on July 2016 and had been there for a long time (months) when we arrived to collect samples.
SK: There can be a single or multiple reasons behind a stranding event, like disorientation, escape responses or sickness, for example. These dolphins also form large groups and have very tight relationships compared to most cetaceans, which is also believed to be one of the reasons behind their strandings in such large numbers and why some apparently healthy individuals also engage in this behavior. I intend to assess the mitochondrial genetic diversity of the group and compare the data to that of other locations that have been studied to see how the population off Chile integrates into the bigger picture. For relatedness within the group, I’m using microsatellites, which are very fast evolving regions of the DNA that can accumulate variations in just a few generations. By using a good number of these markers, you can perform a kinship analysis (inferring how related individuals are to each other), similar as it’s done in some paternity tests.
TFUI: Why is your research important?
SK: Mass strandings of long-finned pilot whales are quite common worldwide and at least four mass events have been registered in Chile, with up to 125 individuals in a single event. These are great opportunities to gather a lot of samples in a very short time, which is not usually the case when working with large animals like cetaceans. These samples can later be used in a variety of areas, like in trophic studies with stable isotopes, accumulation of heavy metals and genetics. Regarding the latter, a few studies have assessed the genetic diversity of this species in the southwest Pacific and the North Atlantic, but no research has been conducted in the southeast Pacific. So not only will this be the first insight into the genetic diversity of the individuals found off Chilean waters, but it also will be filling a void of information for the general area, giving a first approach to how the animals of this area relate to the others.
TFUI: And what else?
SK: It also helps to gain insight into the social dynamics of the organism you study, which is not only interesting on its own, but can be helpful in other disciplines like conservation. Recently, we published a paper in which we studied this topic in bottlenose dolphins off northern Chile, in the Isla Chañaral and Choros-Damas Marine Reserves. Broadly, by photographing the dorsal fins and studying the mitochondrial DNA, we found that in this area two groups of dolphins can be seen: a resident-coastal and a transient-pelagic group. The dolphins of the resident group are permanent inhabitants of the Marine Reserve and are adult females and their descent, both male and female. On the other hand, individuals from the transient-pelagic group can be seen going in and out of this area. Mitochondrial DNA is maternally inherited, so all descendants in the resident group share the haplotypes with the resident mothers. In closed populations like this one, inbreeding (to reproduce with a close relative) can be a problem and in this case, we think this is avoided by allowing the entrance of transient males into the resident group to keep a healthy level of genetic diversity. Transient dolphins are identified through photo-IDs of the dorsal fin and their mitochondrial DNA because, at times, their haplotypes were not found among the resident dolphins, suggesting the mothers of these males belonged to a different (i.e. pelagic) group. To look into the input of non-resident males to the resident population with more detail, we used microsatellites and are currently analyzing the data and working on the paper.
TFUI: In a previous conversation, you briefly talked about how sharks are more similar to cetaceans than fishes in their life histories. What?!
SK: People usually associate sharks with fishes rather than cetaceans, which is correct, but it’s quite a different story when it comes to their life history traits. Unlike most bony fishes, the strategy of sharks is similar to that of large mammals: long lifespans, slow growth, sexual maturity at advanced ages and a heavy energy and time input into their offspring, by having rather long development periods and few descendants. The survival rate of these young animals is rather high if compared to fishes, which usually have shorter lifespans, yield an enormous amount of eggs which have lower survival rates. Sharks “traded” having offspring in large numbers for fewer descendants, but with a higher survival rate. For instance, some species need several years more than us humans to reach sexual maturity and can have a gestation period of up to two years, like the spiny dogfish. The only difference with cetaceans would be that sharks don’t have parental care the way mammals do. Some species manipulate their eggs to hide them in crevices or algae, but their young are independent as soon as they are born.
When facing current fishing pressures, all this makes them very unproductive and slow recovering. They also are vulnerable to other problems the ocean is facing nowadays, like habitat loss, seen in the degradation or even loss of nursery areas.
TFUI: True. Go on...
SK: So, on both likeability to the general public and fecundity, sharks pulled the shortest straws: they don’t look as friendly and charismatic as cetaceans and they don’t reproduce as fast as fishes. In conservation, this is a terrible combination. For example, in Chile all marine mammals are protected, but sharks are under no regulation aside from the ban of finning from 2011. Just basking sharks, whale sharks and white sharks, the latter two rather uncommon, must be immediately released upon capture. Blue sharks, makos and porbeagles are the most extracted species of sharks -targeted or as bycatch- but no fishing quotas or minimum landing sizes have been established. This blog entry from Southern Fried Science exemplifies this worldwide problem with the case of the tuna fishery, where an effective reduction of dolphin bycatch was successfully demanded by a group of people, but consequently a lot more sharks and other fishes were caught.
TFUI: A good read from them!
SK: Among skates and rays, the yellownose skate is the most important national fishery and was so heavily fished that it was declared “depleted” in 2013 and descended a tier to “overexploited” from the next year to date, which is slightly better, but still not the ideal. Since 2012, a year-round fishing ban for this skate was established for most years, only allowing a percentage as bycatch in other fisheries and extraction for scientific purposes. Nowadays the fishery is closed only in the summer months, but as an elasmobranch, it will take a considerable time until we see an evident comeback in their numbers.
TFUI: So what has been your toughest experience out on the field or lab?
SK: I’d have to name two. The first one was in 2014, while on a tagging expedition around the Archipelago of Juan Fernandez. It was my first time working with live sharks, so naturally I was very excited and had really high hopes. During the two weeks of intense work we saw no sharks, except for a mako that managed to escape, as we later saw on one of the cameras. The daily routine with no results was very tough to deal with, to the point that one day I thought I had seen a shark (where there was none), but I had everyone react so fast I didn’t stop to think about it. It only occurred to me later when someone else pointed it out. We laughed about it, but I still felt pretty bad. Fortunately, one afternoon our way back to Valparaíso we struck gold and got to sample a lot of blue sharks and a mako. Six blue sharks and the mako also got to sport a fancy satellite tag, so despite the difficulties, in the end all turned out quite good.
TFUI: Dang! And the second?
SK: The second experience took place this January, while camping on a very small uninhabited island of the Antarctic Peninsula. One “night” (because on that date it’s never actually dark) bad weather was inbound on the northern part of the peninsula. From around 10 PM we went through two (very unpleasant) hours of securing tents, equipment and the boat under heavy gusts and sleet. One of the larger tents collapsed a few times, two poles of my tent broke under the wind force and one tore through the flysheet, which we had to replace. Walking around the campsite had to be done with special attention because of the wind and the icy floor. Luckily no one got hurt and we all got to take off our wet clothes to sleep warm and dry.
TFUI: Do you think people in your country have a good relationship with the ocean environment?
SK: Given the coast of over 4000 km we have, I believe there’s a lack of culture and education around the ocean. Although a growing number of people are gaining awareness of the problems the ocean faces, we still have a long way to go to really see the ocean integrated into our daily reality. Some of the problems I see are not uncommon worldwide: littering, unawareness of seasonal fishing bans and minimal fishing sizes of seafood, and great business and political interests involved in the fishing industry that hinder its correct management. Basically the ocean is thought of as an oversized swimming pool and a food provider, and not as the large and complex ecosystem it really is.
SK: Improvements have been made, though. Many marine protected areas have been created lately, there is great opposition to the construction of some large coastal industrial projects and plastic bags were banned from all coastal localities. Some nonprofit organizations are investing a lot of time and effort into this, with positive results. I’ve also seen more beach cleanup events and citizen science initiatives on social media. For example, many diving centers are starting to record the marine life they see. Activities like whale-watching and visiting penguin colonies are also common in the north during the summer. These, if done responsibly, are a great way to bring the ocean closer to people. To address this problem, short and long term measures can be adopted. Short term solutions include changing your own habits, raising awareness through campaigns and sharing information on a small scale, via social media for example. But to effectively get to the source of this issue, I believe education is -and will- be the best tool to achieve it. I like the idea of mandatory school topics regarding the ocean and environmental responsibility, to develop an interest for the ocean in future generations from an early age.
TFUI: Have you found speaking multiple languages helps you when discussing science (i.e. do you find you have a larger network because you speak multiple languages)? Do you think speaking multiple languages helps with your science outreach efforts at all?
SK: Not having to rely on a translator definitely makes interacting a lot easier, from asking for directions to networking. At meetings and conferences I’ve seen people group with those that speak the same language, which can reduce your chances of meeting new people. I speak Spanish, English and German and all have been useful at some point, on conversations of my own and also helping others by assisting in translation. The same applies to social media, where speaking more than one language can give you access to more information. Your outreach potential can also get a boost, by giving you the chance to translate information to make it accessible to people that don’t speak it. For example, this could be especially useful when conducting a study in a place where not many speak English and wanting the information to be accessible to locals.
TFUI: True. Speaking of wanting information - what’s your dream research project?
SK: This is a fun but also complicated question! It’s hard to narrow it down to a single idea. I’d love to work on shark conservation using the tools and skills I’ve learned so far, like molecular ecology and satellite tagging. I like both lab and field work, so I’d include both in the project. It would include numerous species and different environments. There are some species I have previously worked with which I’d love to see again, like makos and porbeagles, and many more remain on my bucket list (hammerheads, threshers & salmon sharks might be the top 3). Other more emblematic species like sawfishes, because of their vulnerability, would also be interesting. A project with any or multiple of these species would be fantastic!
SK: The same goes for marine environments. Ideally, this project would allow me to visit different places. I’ve mainly worked with sharks of the open ocean and I’d be thrilled to work with species of higher latitudes or reefs.
Also, in any dream research project, as little paperwork as possible is a must!
TFUI: What has your academic experience taught you about yourself, your career path and, ultimately, the sharks?
sk: Maybe the most important thing I’ve learned in my short experience is that I made the right career choice. I’ve always been a curious person and I’ve always had an interest for sharks and the ocean, so it’s a great feeling to be doing for a living what I always liked. It gives some peace of mind in rougher times and I really can’t imagine doing anything else. I’ve learned a lot, visited many breathtaking places and have met great people along the way. I also developed an interest in other organisms, like cetaceans. I’ve been collaborating in interesting research on this topic for some time and now with my thesis I’m doing some of my own.
TFUI: What does the rest of 2018 have in store for you?
SK: My priority is to finish my Master’s, which means a lot of work is inbound. I want to continue my studies abroad and dedicate myself to sharks full-time, so I’ll be also taking some time to resume looking into PhD programs and researchers with whom I share interest.
TFUI: Good luck!
THE FINS UNITED INITIATIVE WOULD LIKE TO THANK sebastian FOR HIS TIME AND WE WISH HIM WELL ON HIS CURRENT/FUTURE PROJECTS!
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TFUI Founder Melissa C. Marquez is author of all animal bios and "Behind the Fins" segments.
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