Mark Enarson

YOB: 1971
Experience: Physician, Shark Diver/Photographer
Regions: Edwards Island/Chatham Islands NZ, Australia, South Africa, Mexico
Interview Location: Telephone (Guelph-Edmonton, CA)
Interview Date:  02 September 2016
Post Date: 17 April 2020; Copyright © 2020 Mark Enarson and Steve Crawford

1. WHITE SHARK CAGE DIVING EXPERIENCE GLOBALLY AND IN AOTEAROA/NZ

CRAWFORD: Mark, you've spent significant time Shark diving in New Zealand waters, but I think it would be a good idea for us to start by characterizing the basis of that experience. Please give me a sense of your history of you being a scubadiver in marine environments generally?

ENARSON: Ok. I've been doing this for about twelve years. A little bit of learning to scubadive came before that, but the actual work has been about twelve years. It started closer to home, in California, and then spread out. Although there was no cage diving in California, it would be illegal in those waters. Then through South Africa, Australia, New Zealand, Mexico. Those would be the main sites.

CRAWFORD: When you say 'the work' - specifically what do you mean?

ENARSON: I’ve been photographing and informally studying White Sharks for about twelve years. Partly for personal goals, and partly working towards a book. Along the way, I've gotten casually involved in some research and other adventures.

CRAWFORD: When you started White Shark diving, I think you said something about starting close to home. When you said 'California' did you mean the Farallon Islands? 

ENARSON: I did, yep. That's what I meant.

CRAWFORD: That was your first exposure to White Sharks? 

ENARSON: Yeah, I believe so.

CRAWFORD: You said something about cage diving being illegal there? 

ENARSON: Yeah. You're not allowed to intentionally enter the water and attract a White Shark in California. 

CRAWFORD: Correct me if I’m wrong, but isn’t there a tour operator that runs a White Shark cage diving operation out of San Francisco?

ENARSON: There's three. But they are under very, very strict limitations. 

CRAWFORD: What can they not do - that, for instance, the cage dive operators in New Zealand can do? 

ENARSON: The law as it's written states that they cannot put anything in the water that is intended to attract a White Shark, except a Human Being. The reason they put the phrase 'Human Being' in, is to protect accidental ... like a bodyboarder that has an encounter with a White Shark, of being accused of attracting it. There are some special dispensations where they're allowed to use a stationary decoy, but nothing beyond. 

CRAWFORD: No berley, no chumming?

ENARSON: Nothing.

CRAWFORD: My understanding is that those constraints are actually relatively recent, within in the last five to six years. Are they not?

ENARSON: No, I think they're beyond that.

CRAWFORD: I’ve got some basic information on California that I collected before, and I’ll get back to check that. Alright. So, when you first started, was it the case that these cage dive constraints were in place? 

ENARSON: Yes, I believe so. When I was there, they used nothing but decoys. 

CRAWFORD: Did those decoys successfully attract White Sharks to the cage. 

ENARSON: No. With one exception. They said they used an auditory decoy late in the day, and they did have a Shark come up on the decoy. But it took more than eight hours to get a Shark. 

CRAWFORD: And that was your first experience attempting to see a White Shark, underwater in a cage? 

ENARSON: Yes, exactly.

CRAWFORD: And you didn't see any White Sharks on that first attempt? 

ENARSON: I saw one breach on a decoy, and I did not see any from the cage. We saw a couple natural predation events, and a breach in the distance - all natural events.

CRAWFORD: By the way, are you aware of the book 'Devils Teeth' by Susan Casey? 

ENARSON: Yep.

CRAWFORD: Was your Farallon cage dive in the same region?

ENARSON: Same exact place.

CRAWFORD: Ok. I'm presuming that this was you as a tourist. That you paid money to the operator to go out to the Farallons for cage diving?

ENARSON: Yes.

CRAWFORD: Did that continue for some time, and then you switched over and developed more pf a collaborative research arrangement with the cage dive operators? 

ENARSON: In most cases I still pay. I think they would have a hard time to operate without me paying, because they have to cover their costs. But yeah, over time a more collaborative relationship formed. 

CRAWFORD: Right. We'll get back to that later. How many different trips did you make to the Farallon Islands?

ENARSON: A total of five, I think. 

CRAWFORD: Of those roughly five trips you took to the Farallon Islands, at what point did you start to see White Sharks while you were in the cage?

ENARSON: Never. I've never seen a White Shark underwater at the Farallons.

CRAWFORD: And not for lack of trying. 

ENARSON: Yep.

CRAWFORD: These were in the early days. And then you started to move around the globe more extensively for White Shark cage diving?

ENARSON: Right. 

CRAWFORD: What did you do next, with regards to White Shark cage diving? 

ENARSON: I had one or two trips to Guadalupe Island. 

CRAWFORD: A very different environment there in Mexican waters.  And also a very different regulatory framework for Shark cage tour dive operations as well, yes? 

ENARSON: Yeah, which has changed over time. 

CRAWFORD: What was the framework like, when you first went to Guadalupe Island? 

ENARSON: That’s hard to remember because it changed so much. And it's been awhile. 

CRAWFORD: Fair enough. I've heard some people describe it in the early days as being like the 'wild west.' The operators could and would do whatever to get the Sharks in to the cage. There were virtually no constraints back in the day.

ENARSON: I wasn’t there in the operators' first days. So, I can’t comment on that. But I think in my first days, I suspect baiting and berleying was illegal, and it was just widely done without permission. 

CRAWFORD: Ok. But to the best of your memory, for your first experience at Guadalupe Island, berleying was not allowed there either? 

ENARSON: Yeah. If it wasn’t my first trip, it would have been soon after.

CRAWFORD: Ok. When was the first time that you saw a White Shark at Guadalupe? 

ENARSON: Oh, the first trip. It's easy there. 

CRAWFORD: And a very different environment. I've been told that the water quality, water conditions, water temperature are all very different than the Farallons? 

ENARSON: Oh, very different. Yep. 

CRAWFORD: Can you describe those differences? 

ENARSON: It's more of a pelagic environment. So, the water is very, very clear. There is at least thirty metres of visibility. It's at least five degrees warmer than the Farallons. 

CRAWFORD: And if you were to contrast with visibility at the Farallons, what would that be roughly? 

ENARSON: Oh, the Farallons are very murky. 

CRAWFORD: Like on the order of ten metres visibility?

ENARSON: No, less. Five metres. 

CRAWFORD: Alright. Roughly, how many times in total did you dive Guadalupe? 

ENARSON: It's be around ten trips. 

CRAWFORD: What was the range, in terms of number of White Sharks, that you would have seen on any given trip? 

ENARSON: It would usually between ten and twenty. 

CRAWFORD: Ten to twenty different individuals, you figure? 

ENARSON: Yeah.

CRAWFORD: Tell me about your understanding of the biological relationship, if any, between Guadalupe White Sharks and Farallon Island White Sharks? 

ENARSON: Limited. They've only tracked one animal moving between the two sites. So, there is very little exchange of the two populations on the coast. Whether the two groups would meet out in the middle of the Pacific is, I think, quite unknown. They go to similar places, but when you're talking about those places, they cover an enormous area of the Pacific Ocean. 

CRAWFORD: Right. Based on your understanding of the current state of affairs, do you feel that there is evidence that would support the claim that they belong to a single biological population? Or is there a fairly strong degree of discrimination between two populations or subpopulations?  

ENARSON: We're talking about the Guadalupe population ...

CRAWFORD: And the Farallon Islands, yeah.

ENARSON: They're probably fairly isolated. 

CRAWFORD: Ok. Characterize for me, please, the general demographic of the White Sharks at Guadalupe. Were you were seeing juveniles rather than adults, for the most part?

ENARSON: No, it was a huge mix. We saw at least one that would have been two or three years old, there was a mix of sub-adults, and then there was quite a few adult White Sharks there. It was a big mix.

CRAWFORD: It was mix. On any given day as well, right?

ENARSON: Yeah, on any given day.

CRAWFORD: What about the distinction between males and females at Guadalupe? 

ENARSON: In the early season, starting in July, it's predominantly males. Moving towards fall, say September - October, the females move in. There's a period when they are quite mixed. Then males leave, and by January it's predominantly females. 

CRAWFORD: Ok. Was there a progression from smaller males to larger males, early in the season? 

ENARSON: No, I don’t know that that's true.

CRAWFORD: Ok. In terms of causal mechanisms that could account for the Guadalupe site being an aggregation hotspot ... based on your knowledge, what ideas have been put forward with regards to why those White Sharks are there?

ENARSON: Well, the large Seal population would have to be part of it. But whether that's sufficient, I don’t know. Whether it is the cause of them being there or not, it's certainly proposed that it is a mating site. 

CRAWFORD: It has been. In terms of the evidence that's been collected to date regarding that hypothesis, do you have a sense of whether it is strongly supported or still highly uncertain? 

ENARSON: There is a degree of uncertainty, and I think there's still some disagreement. But I think there is some compelling nature to it. I think, above all, when you track these animals for five years, and you show that the adult males and females are not together at any other time of the year, other than at Guadalupe - that has some compelling nature to it. 

CRAWFORD: Any direct evidence that would perhaps be associated with courtship and mating? Like scarring on the females, or anything like that? 

ENARSON: Sure, but you see scarring on the females in numerous sites. So it's hard to say that categorically defends it as a mating site. 

CRAWFORD: Fair enough. Last question in this regard ... in terms of what has been referred to as the ‘White Shark Cafe’ - the offshore mid-Pacific aggregation - I'm presuming that at least some of the  White Sharks from Guadalupe also travel offshore for great distances. Do you know they also go out to what has been referred to as the 'Cafe'? 

ENARSON: Yep. They go to the same place. 

CRAWFORD: What's your understanding about what happens out there? 

ENARSON: I think that's a very open question with very little direct evidence. I mean they must feed. They must, they're just gone too long. The females are out there for nearly two years. So, they must feed. But beyond that, I think it's very hard to speculate. 

CRAWFORD: We are just about to explore your experience with White Sharks at other locations globally. Other than the Farallons and Guadalupe, what other places in the world have you done a fair amount of White Shark cage diving? 

ENARSON: I spend a lot of time in South Africa, but I do little cage diving there. I don’t spend much time in the actual cage in South Africa. It's more of an above-water hunting site. There is a lot of cage diving happening, I'm just not participating there. 

CRAWFORD: Ok. Clarify for me - what are you doing with the White Sharks in South Africa, if you’re not cage diving? 

ENARSON: I'm on the cage diving boats, but I'm primarily trying to photograph hunting behaviour. 

CRAWFORD: As in, White Shark breaches? 

ENARSON: Sure. That's one way to put it, yeah.

CRAWFORD: What other way would you put it? Please elaborate on that for me.

ENARSON: It's really trying to photograph the entire ecosystem as it pertains to the White Shark hunt. So, some of the Seal behaviours, the island itself, and the hunt between the Shark and the Seal. Not all of it is breaching. Some of it is just surface stuff. Breaching is certainly the most dramatic aspect of it. 

CRAWFORD: So, your work .. I mean it's a hobby, but you're taking this very seriously. The work that you are doing in South Africa, observing the White Sharks in a broader kind of ecosystem context, both in terms of habitat, but also in terms of their prey ... That work is surface-oriented in terms of your perspective. You are using different cameras, but capturing images of that aspect of White Shark ecology from a different perspective. Yes? 

ENARSON: Yes, exactly. 

CRAWFORD: You said ‘the island’ - which island in South Africa was that?

ENARSON: Seal Island, off Cape Town.

CRAWFORD: That’s one of the major Shark cage dive operations. But  there are others in South African waters, is that correct?

ENARSON: Yep. I've visited them all, but I spent much less time at the other two. 

CRAWFORD: Ok. Roughly, how many trips to Seal Island would you have made?

ENARSON: About 250. 

CRAWFORD: Holy crap!

ENARSON: There's only about four people in the world that have spent more time there than me. 

CRAWFORD: Ok. Let's stick with that experience then. In general, if I were to ask you about the most important lessons that you've learned about White Shark ecology from your mostly surface observations at Seal Island in South Africa ... what are the most important things that have stuck with you?

ENARSON: That’s a hard question. 

CRAWFORD: I can be more specific, if you like?

ENARSON: Yeah, sure.

CRAWFORD: Ok. Let’s start with compare and contrast. What type of demographic patterns through time, if any, in terms of juveniles and then males and then females? What kind of temporal patterns might you have seen at the Seal Island site? 

ENARSON: Again, there is quite a mix. Although they are much like at the Farallons. They are a little bit geographically-isolated around the island. There are areas that are predominantly male, there are areas that are predominantly female. There are only a small number of mature animals there. They're mostly sub-adults. Although they can be quite progressed in their sub-adulthood. But most of the animals leave before they're fully mature. Well, that's hard to say. There is a smattering of what seem to be mature adults. But they seem to be by far the exception. And there are some quite small juveniles there as well. 

CRAWFORD: Ok. In terms of their behaviour, when you compare Seal Island to Guadalupe, were the White Sharks behaving relatively similarly? Or were there any distinct differences?

ENARSON: No, I would say it is categorically different. But I think it has a lot to do with the way Guadalupe is built. I think that almost all of the hunting behaviour at Guadalupe is completely out of reach for us, because it happens at considerable depths. They're hunting quite different prey types. 

CRAWFORD: Please expand on that. What do you mean by 'different prey types'?

ENARSON: You don't see a lot of hunting on the California Sea Lions or Fur Seals around Guadalupe. There is certainly evidence that they're hunting the Elephant Seals, but an Elephant Seal is a very different animal for hunting. Wherever White Sharks are hunting Elephant Seals, they seem to do so at depth. The Elephant Seals swim much deeper, and they have considerably greater lung capacity. So, the White Sharks are hunting them at depth. You rarely, if ever, would see the initial strike. Whereas, when you're talking about a Fur Seal, which is more the model of Seal Island, Fur Seals have much less lung capacity. So, they're spending more time at the surface, and so you're seeing more of a surface event. 

CRAWFORD: Roughly, what would be a typical dive time for an Elephant Seal versus a Fur Seal? 

ENARSON: I'm not going to be able to give you perfect numbers on that, but I think that an Elephant Seal is at least in the tens of minutes. They go on substantial dives. I think they can probably get up to thirty minutes, closer to Whale-like numbers. Whereas a Fur Seal, they do not take long dives. Maybe a minute or two. 

CRAWFORD: And you would generally expect, in terms of the animals being able to hold their breath, that duration would have a direct relationship with the depth of the dive itself?

ENARSON: Yes.

CRAWFORD: Ok. In contrast to Guadalupe, at Seal Island you saw quite a bit more surface predatory behaviour by the White Sharks?

ENARSON: Yes. The implication of your question is a little bit off. There is very little effort made at Guadalupe to engage in the natural behaviour of White Sharks. It's a big, big island. Whereas Seal Island is a very small island. And with Guadalupe being well out into the Pacific, the weather patterns are quite dominant. So, I think partly out of necessity, the diving program at Guadalupe has been largely confined to a single location. And it has become very formulaic, they do the same thing every day. They're really just trying to show you a Shark from the cage, do it safely, and get out. Whereas Seal Island is more of a natural history type of trip, where they're exploring all sides of the Island, they're moving around quite a bit, and they're exploring natural behaviour more. 

CRAWFORD: Ok. Thank you for the clarification. With regards to the operation at Seal Island, you said it is not just about the Shark cage dive operation, it has expanded more into natural history. Is the White Shark tour program there connected in any way with an ongoing White Shark research program? 

ENARSON: Yes. The boat that I spent the majority of my time on, which is Chris Fallows' boat - he has collected data on his own since he started going to the Island. A lot of that data has found its way into scholarly research. Occasionally a Scientist will be on the boat. But by-and-large, in the current era, the researchers are on their own boats, and quite separated from the cage diving operation. 

CRAWFORD: Alright. Let’s get to the cage dive operations themselves. Are they qualitatively similar in many regards to White Shark cage dive operations throughout the different hotspots around the globe? 

ENARSON: Yeah. With the difference that all of the boats at Seal Island would put maybe an hour or two of the morning into trying to follow and witness natural hunting behaviour. Which is not done anywhere else. At a certain time in the morning, the natural predatory behaviour will die down as the light comes up, and the Sharks lose their predatory advantage. When the predatory activity falls, then it becomes a very standard cage diving operation. 

CRAWFORD: Is berleying allowed in South African waters?

ENARSON: It is, yeah. 

CRAWFORD: Do you know what kind of fish or anything else that they would use for berleying?

ENARSON: It's local fish from their fish markets. 

CRAWFORD: But is it fish of a particular kind? Would it be high in some tissue type, or would it have certain characteristics? Or is it just any fish that they would get from the market? 

ENARSON: I think it's a mix. So, I doubt it. 

CRAWFORD: My reason is, I'm anticipating when we start talking about New Zealand, the fish that both Peter Scott and Mike Hanes use for berley is typically Tuna. They've found that particular species creates berley that has a much greater effect than other types of local species. 

ENARSON: Yeah, sure. I haven't seen that sort of specialization in the berleying in South Africa. It seems to be a mix of the available fish species. 

CRAWFORD: Ok. Roughly, what are the water visibility conditions at Seal Island? 

ENARSON: Seal Island is murky. It’s about five to ten metres.

CRAWFORD: So, kind of like the Farallons?

ENARSON: Yeah. 

CRAWFORD: Ok. Getting back to the demographics and behavioural responses of White Sharks to the berleying and cage dive operations at Seal Island, is it similar to what you've seen elsewhere around the globe? 

ENARSON: Yes and no. I think that the South African White Sharks are hunting a lot more activel than the Sharks at a lot of the other locations. There are times of day, or certain days, when you simply cannot attract them. They just will not come to the boat. 

CRAWFORD: Is that because they're off, busy doing something else? 

ENARSON: I believe so.

CRAWFORD: And that something else would be - following their normal predatory behaviour? 

ENARSON: Exactly. And if they're following their own predatory behaviour, you can't attract them by any means.

CRAWFORD: That is a very interesting observation. 

ENARSON: Yeah. It's a perspective that I think a lot of the opponents of cage diving lack. You can't attract a White Shark that doesn't want to be attracted. 

CRAWFORD: Thank you for that. Ok. Anything else in terms of your experience at Seal Island in South Africa that might shed some insight into White Shark ecology and behaviour in general, or cage dive operations in particular? 

ENARSON: That is a huge question.

CRAWFORD: I'm just trying to say, was there something else big that always struck you - that I have not asked you about. That was basically the question. 

ENARSON: I think having read your stuff, what you are getting at ... I think South Africa, more than most other places, situate the Sharks in the context of doing their own natural behaviour. They've been operating there on some level since 1996. And with a lot of attention put towards identifying individual Sharks and trying to collect good data. You see these animals, identifiable individuals at natural events. And you see individuals at the boat. I think in a way, that isn't possible at any other location, we've been able to identify individuals who are active, effective hunters that can be regularly seen at natural events. You know they're nearby, and they never ever visit boats. I don't think that's a perspective you can get in many other places. Because, for example in New Zealand or Australia, if the Sharks are at their natural behaviour, they're on the bottom, and you'll never see them. There's no way to identify an animal that doesn't approach. Whereas, because there's a surface-related activity that is visible in South Africa, you can see a variety of individuals who are present and pursuing natural behaviour, and have no interest in Human activities whatsoever. 

CRAWFORD: Ok. Just to clarify here, I'm really not trying to leading you to any particular conclusion. I have certain questions, but I am not trying to elicit a particular response from you in any way. 

ENARSON: More what I mean is, there was a lot of stuff in what Peter initially sent about sort of Indigenous beliefs about cage diving, effects on Sharks, and all of those other things. That's really what I was alluding to. I think at least part of your study, as I read it, is to get at Indigenous beliefs and other beliefs about the effects of this whole industry. That's more-or-less what I mean. That there at least is an aspect of the research to say "What is the effect of these activities on the Sharks?" Whether I've read that correctly or not. That's really what I mean about it. Not that you're leading me into anything. But that you're interested in belief systems around the effects of these activities. 

CRAWFORD: From different knowledge systems, yes. Where belief and evidence are both components of each type of knowledge system - Indigenous, Local and Science. When you say 'Indigenous' do you mean Local?

ENARSON: Local knowledge. 

CRAWFORD: Ok. For me, I'm interested in both Indigenous and Local knowledge systems, as well as the Science knowledge system.

ENARSON: Sorry. What I meant is 'non-participants' in the area. 

CRAWFORD: Ok. That's one of the advantages of this kind of interview format. That is a question I had not anticipated asking you, and now I am dying to know. Based on your extensive trips out to Seal Island, did you ever get a sense of any Indigenous South African perspective on the White Sharks? Did the Indigenous people there have these White Sharks embedded in their culture? Or was their knowledge about the White Sharks perhaps different from the cage dive operators of the Scientists?  

ENARSON: Not to a great extent. There's a little bit of interaction with people who would have some sort of Indigenous background, who were associated with the fishing industry - people who now work with cage diving operations. I've never gotten a great sense of what their Indigenous beliefs might be regarding the White Shark. I've never sensed that the South Africans have a very deep historical view of them. 

CRAWFORD: I know it's a complex situation, especially for someone from another country. You are there as a visitor, a tourist, a professional person, you are there for a limited period of time. The kind of exposure you can get with the Local knowledge system, and especially the Indigenous knowledge system ... I wasn't expecting there would have been a great deal of exposure. It would have been accessory or supplemental to your trip, right? 

ENARSON: Very, very little Indigenous content. 

CRAWFORD: Ok. Last thing before we move away from South Africa ... What about White Shark attacks on Humans? What do you know about attacks in that region? 

ENARSON: Well, I know quite a lot. So, again, it's a very general question. 

CRAWFORD: Alright. You spent most of your time at Seal Island, but there are several other White Shark aggregation points in South African waters. Is that correct? 

ENARSON: Oh yes, many. 

CRAWFORD: Is there any reason to believe that Seal Island would be typical, or perhaps different in some way, from the others?

ENARSON: Quite different, actually. 

CRAWFORD: How would you characterize those differences?

ENARSON: For example, contrasting it to the second most highly studied location, which would be at Gansbaai. The types of predatory activity are quite different between the two islands, and the current thinking is that the underwater geography around Seal Island is quite flat and is quite featureless, mostly just a sandy bottom. There's very little in the way of refuges for Seals leaving the Island, for example Kelp forests, etcetera. Whereas at Gansbaai, the bottom is quite a bit more varied, and there's an extensive Kelp forest extending off the island. So, the Seals can use the Kelp forests and the bottom as cover, in a way that they can't at Seal Island. So, the type of predatory interactions are quite different, because the Seals have absolutely nowhere to hide at Seal Island. 

CRAWFORD: If I asked for an example of a major way that White Shark predation is different between Gandbaai and Seal Island, what would you say? 

ENARSON: I guess what I was leading to was that we've seen up to fifty predation events in a day at Seal Island, whereas they're considerably less common at Gansbaai, because the Seals are hiding on their way out from the island. So, the Sharks have to use a different hunting tactic than they do at Seal Island, and possibly some of the events are less visible. 

CRAWFORD: Right. With regards to White Shark attacks in South African waters, is there a geographic discontinuity in terms of the frequency of attacks on Humans? Are there places where they happen more than others?

ENARSON: Sure. But I think, by-and-large, and this is true of almost everywhere. The attack hotspots have a lot more to do with the Human water usage, than they do with Shark movement.

CRAWFORD: That’s a theme that has been articulated by many people. Taking that into account, are there places where - all things being equal - there are a greater risk of attacks than others? Or is it best explained solely by the frequency of Humans in the water? 

ENARSON: Almost exclusively, I would say. Because the hotspots of attacks are almost always at surfing locations.

CRAWFORD: Are the White Shark cage dive operations in South Africa typically at a removed distance from the surfing locations? 

ENARSON: All except one location. At Mossel Bay, the dive location is extremely close to the surfing location. The other two locations are removed by eight to ten kilometers. 

CRAWFORD: When you think about it, for a big fish like a White Shark, even eight to ten kilometers is not that great a distance.

ENARSON: No. They might make that trip every day.

CRAWFORD: Yeah. What is the reaction of surfers to the White Shark cage dive operations in South Africa?

ENARSON: I think it varies. Of course, you can never categorize an entire group of people with one statement. But there is a fair amount of hostility. 

CRAWFORD: Have those surfers suggested that the White Sharks have interacted with them more frequently and/or more aggressively, since the cage dive operations?

ENARSON: I don't know if they'd put it that way. But I think there's an implication that's quite similar. That the cage dive operations have somehow modified White Shark behaviour, and put them at risk. 

CRAWFORD: Has there been any research in South Africa to address that uncertainty?

ENARSON: Yep.

CRAWFORD: What do you know of that research?

ENARSON: That research has found no link whatsoever. 

CRAWFORD: Was that research involved with the cage dive operation you frequented? 

ENARSON: It was done in the location, but it was not associated with. 

CRAWFORD: So, it was done by researchers working on an independent vessel? 

ENARSON: Correct.

CRAWFORD: The researcher looked for, and failed to find, evidence of effects by the cage dive operations. How did they assess the probability of Shark-Human interaction?

ENARSON: In a variety of ways. They were assessing Shark's interactions with baits and vessels. And the stuff as it pertained to whether a Shark would generalize the experiences around a boat to, say a surfing condition - that was more of a philosophical looking at the factors involved. 

CRAWFORD: As far as you are aware, there was no empirical assessment in that regard? 

ENARSON: Not directly. They looked at the degree to which the Sharks interacted with baits and vessels, and then they looked at the multi-steps required to associate a stimulus with a novel situation. And they felt that the available data did not support each step of that transition. 

CRAWFORD: Alright. Moving on ... where else, other than New Zealand, have you engaged in observations of White Sharks? 

ENARSON: I spent considerable amount of time in Australia. 

CRAWFORD: Where specifically?

ENARSON: At the Neptune Islands. 

CRAWFORD: Is the Neptune Islands site the only location in Australia with White Shark cage dive operations? 

ENARSON: Yes, it is. 

CRAWFORD: When did you start with those trips?

ENARSON: December 2009.

CRAWFORD: Roughly, how many trips to Neptune Islands would you have taken? 

ENARSON: Twenty-five to thirty.

CRAWFORD: In terms of location, is it a fairly specific area that the operator goes out too? 

ENARSON: Yeah, very specific.

CRAWFORD: What is your understanding about the regulatory context? About the constraints the operator may have to work under, in comparison to the other places? 

ENARSON: They are close to the standard. Berleying and baiting is allowed. There are operational and non-operational days. They have been given days where they are not allowed to operate, just to give the Sharks a rest, if you will. It depends what all you want to know.

CRAWFORD: Just in general, like you've described. It seems for the most part, they are typical Shark cage dive operations? 

ENARSON: Very typical. There isn’t anything really unique about them.

CRAWFORD: Let's follow on the previous theme then. How was it similar or different in terms of environment and in terms of the prey, relative to the other locations? Let’s start with the environment, how was it different? 

ENARSON: The environment is an island off the coast of Australia. It takes about four hours to get there by boat. I don’t know the exact miles or kilometers, but it's off the coast, separated from Human habitats, if you will. It is predominantly a diving location. There isn’t a great deal of surface activity there. It is a New Zealand Fur Seal hotspot, so the Sharks are clearly gathered there ... well, to presumably hunt the New Zealand Fur Seal. You would occasionally see such events in the extreme distance, but very rarely would you ever see anything remotely close up. Much like the Gansbaai situation, it has quite a varied bottom. So, the Seals don’t leave and approach the island by the surface very much - they hug the bottom. Any predatory behaviour would presumably be deep. So, it's almost exclusively a diving location. For me, the attraction of Australia is that they're the only place in the world with a commercial bottom diving operation where they'll drop the cage thirty metres. 

CRAWFORD: And that's important for you for what reason? 

ENARSON: To photograph the Sharks in a natural, bottom environment. 

CRAWFORD: Ok. How would you characterize any differences in your observations of White Sharks at Neptune Island when submerged at the surface, versus submerged at a depth of 30 metres? What differences did you see from the White Sharks under those two different circumstances? 

ENARSON: The surface stuff at the Neptunes is very much bait-attracted. So, Sharks curious about baits, or charging at baits. It's very, very similar to what you'd see at Guadalupe, or at Seal Island, or any surface cage diving situation. Whereas, on the bottom under good visibility you can see the Sharks under a slightly more natural situation, and they're a lot calmer. They're not charging after baits. They're just curious and swimming. 

CRAWFORD: 'Swimming' as in swim-by? Or 'swimming' as in circling? Or a combination of the two? 

ENARSON: Combination of the two. 

CRAWFORD: Ok. Have you see any predation events when you were in the cage on the bottom at the Neptunes?

ENARSON: Never. 

CRAWFORD: What's water clarity like at the Neptunes?

ENARSON: It’s Guadalupe-like. It's about thirty metres.

CRAWFORD: That’s interesting. With regard to demographics, specifically with regard to juveniles versus adults, what do you see at the Neptunes?

ENARSON: A big mix. A small number of juveniles, which is true at all these locations. Lots of subadults, and a few mature animals. The sex ratio is seasonal. Part of the year it's mostly males, and part of the year its mostly females. 

CRAWFORD: Is there a progression, in terms of subadults to adults? And/or a progression between males and females during the season?

ENARSON: I think there's probably a slight mixing at the edges of the seasons. But it's pretty all-or-none. 

CRAWFORD: You either have a mix, or you don’t have many of one? 

ENARSON: Yeah. Well, you either have all males, or all females. 

CRAWFORD: I see, thank you for clarifying that. Within season though, is there a pattern to that gender mix? 

ENARSON: I've not noticed it. There might be an individual animal of the opposite gender, but the sex ratio is strong. It's strongly segregated. 

CRAWFORD: Do the males show up first, or do the females show up first? 

ENARSON: Depends on how you define first. In the winter months, it's predominantly female, and in the summer months it's predominantly male.

CRAWFORD: Is there a period, that you are aware of, where there are really no White Sharks in that region? 

ENARSON: There are very few in September and early October. And lately, there's been very few in August, although that’s changed over time. I think March-April are very lean. In the times where the animals would be switching the gender mix, the numbers drop to almost nothing. 

CRAWFORD: Ok, thank you. When the animals are there, I think you said it's mostly females during their winter? 

ENARSON: Yeah, there winter is almost exclusively female. In their summer months, it's almost exclusively male. 

CRAWFORD: Typically never a mix of big males and females?

ENARSON: No. 

CRAWFORD: What's your understanding about the potential importance of the Neptune Islands with regards to reproduction? 

ENARSON: There has been a little speculation, but I don’t think there is any strong evidence one way or another. It doesn’t have the same biological characteristics as say Guadalupe. So, I'm not sure it's a mating location. 

CRAWFORD: What do you know about the knowledge we have about population distribution and migrations, for the White Sharks that you have seen at Neptune Islands? 

ENARSON: The population almost exclusively migrates west. There is a very small number of individuals that go east. 

CRAWFORD: When you say 'west' do you mean all the way over to the western shore of Australia? 

ENARSON: Yep, all the way around. As far north as Exmouth.

CRAWFORD: Would they go across the top of Australia, and then back down to the Great Barrier Reef along the eastern shore? 

ENARSON: They don’t appear to do that at all.

CRAWFORD: What do you know about White Sharks along the northeast coast of Australia? 

ENARSON: It's a different population, but I know a fair bit. It's a population that, by and large, doesn't visit the Neptunes. 

CRAWFORD: Would it be the case that there might be two or three different populations of White Sharks around Australia? 

ENARSON: At least two. The west and south are the same. And then the southeast and east would be another. There is genetic segregation between the two populations. 

CRAWFORD: This is extremely helpful. Because as you have said, you've also read the Science literature that has been published. You are familiar with it. And it gives you a very different insight than your normal cage dive experience. Last question in this regard ... are there linkages between Australia and New Zealand, with regard to White Sharks? What are you aware of in that regard? 

ENARSON: The ones on the eastern coast seem to mix with New Zealand. Not much on the south and west. 

CRAWFORD: Ok. Before we go to New Zealand ... Have you had experience with any other White Shark cage dive operations elsewhere in the world, that we should talk about? 

ENARSON: No, I think we have hit them all. 

CRAWFORD: When was your first trip to New Zealand, for White Shark cage diving? 

ENARSON: 2011. 

CRAWFORD: From 2011 till last year? 

ENARSON: No. 2011 to 2015. I didn’t make it in 2016. I had to cancel both trips.

CRAWFORD: In your five years of cage diving in New Zealand, roughly how many trips did you go out on?

ENARSON: I think it has always been one per year. I tried to do two per year this year, and it didn’t work. 

CRAWFORD: All of those trips would have been out to Edwards Island? 

ENARSON: Yes, with one trip out the Chatham Islands. 

CRAWFORD: Oh, really? You did White Shark cage diving at the Chathams? Who was that with? 

ENARSON: That was with Val Croon. It was with the Hotel Chathams there.

CRAWFORD: A cage for personal use? 

ENARSON: Kind of. He'd only used it eight times before I was there. So, it was very low key. He didn’t have much experience in cage diving. I was largely helping him learn. 

CRAWFORD: What year was that?

ENARSON: 2011.

CRAWFORD: So, your first year. I am actually keenly interested. I didn’t get a chance to go out to the Chathams. But some of the people that I interviewed had direct and indirect knowledge of the situation out there. In some regards, there were very strong similarities with Stewart Island. And in some ways, it was very, very different there. What was your experience with your cage dive operation experience at the Chathams? 

ENARSON: It was the only place I've ever been, where I actually found the Local knowledge and cultural surroundings of White Sharks interesting. It’s a fascinating place.

CRAWFORD: Give me an example of that, please. 

ENARSON: The Chathams in many ways feels decades separated from the rest of the world. It has a much more ‘the way things used to be’ sense to it. The Abalone divers in the communities there have a much more 'back in time' relationship with the White Sharks. They are like the monster out in the waters, that they run in to occasionally while they are diving. They have this very deep atavistic fear of the animal. It's very palpable and very interesting. 

CRAWFORD: You went out on one cage dive trip at the Chathams? 

ENARSON: I was there for ten days. We got out three days, because of the weather. 

CRAWFORD: Realizing that is was on the learning curve for the operator, these were all surface cage dives? 

ENARSON: Yes. 

CRAWFORD: The normal kind of berleying and bait situations? 

ENARSON: Yeah, roughly. With the exception that all the bait was caught on the trip, it was not pre-prepared. Which is not normal. 

CRAWFORD: Did you see White Sharks on those three trips?

ENARSON: Yes. We saw a small number of them on the first two days, because we were at a location at the lagoon mouth on the main island of the Chathams. There's no large Fur Seal colony on the main Chatham Island. So, you’re really talking about a White Shark that just happens to swimming by. Whereas, the last day I convinced them to go out to the Star Keys - which is a large Fur Seal colony. We had a large number of White Sharks that day. 

CRAWFORD: Roughly, how many? 

ENARSON: Five to ten.

CRAWFORD: What kind of mix, in terms of size and/or gender?

ENARSON: I don’t honestly know in this case, because I didn't even get in the water there. I did the entire thing on a pole camera, because at the inland location at the lagoon mouth, the water was so dirty and the visits from the Sharks were so short, that I didn't bother getting in. At the Star Keys the current was so strong, that cage diving was very difficult. I honestly think they were males, but I cannot verify that. Again, I sent the photos to one of the New Zealand researchers and he has evaluated it. But I don't remember the results. 

CRAWFORD: Ok. Your experience cage diving in New Zealand at Edwards Island over five years, with one or two trips per year ... in comparison to the other places where you have been on cage dive operations, how would you characterize the environment at Edwards? 

ENARSON: It's similar in proximity to Human settlement, as the Seal Island location. Much smaller Human habitation than obviously Cape Town itself, that's a much larger city. The diving is clearer water. It's near a very interesting ecological setting, which is unusual for White Sharks. There's trees and birds and things that are not usually there at a White Shark dive location. It's a lot more like Guadalupe as it pertains to the animals themselves. There's a mix of a few very small, lots of subadults, and mature animals of both genders. So, it's Guadalupe-like in that regard. 

CRAWFORD: What about similarities or differences with regard to predatory behaviour?

ENARSON: Very, very few predatory events have been witnessed. I think Peter's seen one in all his years. And I've not seen any. 

CRAWFORD: If I asked you to speculate or hypothesize why that might be the case, what would you think?

ENARSON: Seals aren't swimming at the surface very much. So, I assume that they're using the bottom. 

CRAWFORD: Ok. But we don't have any empirical evidence for that hypothesis?

ENARSON: I would say that the studies that are being done at Stewart Island up till now, are still in a very basic biological level. 

CRAWFORD: Right, ok. With regards to the cage dive operations, have you gone out exclusively with Peter Scott? Or was it a mix with Peter and Mike Haines?

ENARSON: No, I've never been out with Mike. 

CRAWFORD: In terms of your experience with Peter, similarities and differences with cage dive operations elsewhere? 

ENARSON: Honestly, very similar. Peter follows the standard operating procedure. 

CRAWFORD: In terms of the White Sharks' behavioural responses to that kind of standard operating procedure, anything special to note? Or was it pretty much the same kind of things that you see from White Sharks all around the world? 

ENARSON: The one thing I can comment on there, is that I was there from quite close to the beginning of those operations. And so I've been able to see the change in the Sharks over time. I think you can honestly see a very strong habituation response since we started there. 

CRAWFORD: This is extremely interesting for me, because obviously there are very few people with that kind of longer-term perspective. There's Peter, and Michael, and Nicola who has worked with Peter for a couple of years. But you have a unique perspective, in combination with your White Shark background. Tell me about that perceived habituation over the years.

ENARSON: I would say that in the first year or two that I was there, we had a large number of Sharks - which may or may not have anything to do with the cage dive operations. Some of those things have to do with natural forces, and you’re always tempted to put a Human spin on it. But it may have nothing to do with us. We had a large number of Sharks, and the Sharks that were there were very, very keen to interact with the boat. So, the number of interactions and the number of photos that I was getting out of there was huge, because the Sharks were very reliably present and very keen to interact. I think we've seen a steady drop off in that. 

CRAWFORD: Well, that leads to another question. You've been to cage dive operations at different places in the world, repeatedly over the years. Have you seen or heard about that type of White Shark habituation to cage dive operations elsewhere?

ENARSON: Habituation definitely exists. It's been shown in every study regarding cage diving that has been done anywhere. But I think that in the other locations ... cage diving started in South Africa in the '90s, it started at a similar time in Australia, although in a commercial filming basis way earlier in Australia. They're all old, so I don’t think that people were as savvy to look for that kind of thing back then. Plus, there were other factors at play. In Australia, the Shark numbers were much, much lower back in the early days. So, they had a hard time getting Sharks at all. They didn't have the numbers that we do now, under the current protections that White Sharks have. I think in South Africa, there were non-Biologists that were conducting these trips. I think they had a lot more Sharks in those days, but it's hard to say again how much that has to do with other activities, and how much it has to do with cage diving. Whereas, in New Zealand it is all recent and we were able to watch. I think it's hard to exactly say why, relative to the other sites, but I think that the New Zealand site is somewhat unique. Because you're bringing somebody in that has a long history with the Sharks and cage diving, and putting them in a new situation. So, it's much easier to make that kind of observation. Whereas the other ones were more of an evolutionary cutting-frontier-thing. So, I don’t think they have the experience perhaps to make those observations. Whereas, we're taking other knowledge and bringing it into a new situation in New Zealand.  

CRAWFORD: Yes, I think that is a very important point. Let’s consider for the five years at Edwards Island, keeping in mind a very strong sense of this habituation that you perceived ... were you aware of, or did you have access to, any other type of knowledge regarding changes in White Shark abundance over that time period? About whether the actual abundance of the population was going up or down during that five-year period? 

ENARSON: I doubt that anybody has hard data on that. Sharks are very difficult to count. I wouldn’t know what was happening with the population within that five-year period. But I think certainly over the last decade or so, the population in New Zealand has probably increased. Before there were tighter regulations, we did visit one other island nearby. What was it called?

CRAWFORD: Maybe Bench Island? 

ENARSON: Bench, yes. Thank you. We had very little success there, by the way. 

CRAWFORD: Ok. With regards to the White Sharks that you saw on those five to ten trips over those five years, did you get a sense of any patterns in developmental stage or gender of the White Sharks? Were you aware of any patterns through time, over seasons at the Edwards Island location?

ENARSON: Through the season, I think Peter’s impression certainly is that the females arrive later. But I do not have much personal take on that. 

CRAWFORD: Alright. For the trips that you were on, were those early in the season? Later in the season?

ENARSON: I've done a mix. I've never been very early season. I think that the earliest I've done is probably March, and he starts in December-January, I have never been that early.

CRAWFORD: Alright. Mostly toward the end of the season. So, you've seen large females there, as well as a mix of small to large males?  

ENARSON: Absolutely. Yep.

CRAWFORD: [Discussion about project classification levels for human encounters with White Pointers: Level 1-Observation, Level 2-Swim-By, Level 3-Interest, Level 4-Intense]. In terms of your observations of indvidual White Sharks at Edwards Island, roughly what was your sense of the split across those four Levels?

ENARSON: For the different individuals that were there?

CRAWFORD: When you pool them all together, what were the majority of the animals? Were they mostly Level 1 ‘saw them but never really came in close’ or Level 2 Swim-By or what?

ENARSON: From the boat, your opinions are always going to be biased towards the more Level 4 that you're talking about. Because those are the ones that you see. But when you're underneath, you get a perspective of the mix. I think that the interactions are always dominated by the Level 4 animals - those are the ones that leave the biggest impression. But there's always some 3s, 2s, and and maybe some 1s that are around. 

CRAWFORD: That is an extremely good point. So, let’s go only on your observations subsurface. When you were in the water, based on what you saw there, what was the split across those four Levels? 

ENARSON: For animals that are present on any given day, there's going to be like one to three animals that are on that Level 4, that are dominating the bait interactions. There's going to be a number of animals that are on the Level 2-3, they come in occasionally, they have a look, they back up. Honestly, I find it very difficult to categorize the Level 1 animals, because they're often hesitant at a sort of distance that you can't reliably say which animal it was. 

CRAWFORD: Yes, I understand what you are saying there. God knows there are going to be animals that surely know you are there, but at such a distance you do not even see them at all. 

ENARSON: Correct. The other thing I would say is that, every year I send my photos to Clinton Duffy, and I'm always surprised by how many more animals were there than I actually knew. You get animals that come in for one or two half-hearted interactions, leave, and are gone. They don't really leave any impression on you. They move in quickly, you see them briefly, and without being able to digest and analyze, you don’t really count that as a different individual. So, I think we always underestimate the less interactive animals. 

CRAWFORD: Yes. And that's consistent with what I've heard from both of the operators. In terms of the photo identification work, are you aware of what the objectives of that research were? Or what the general conclusions were?  

ENARSON: I think he's looking for basically a population picture of animals at the Island.

CRAWFORD: Using photo ID like a mark-recapture tool?

ENARSON: Yes, exactly. I think he has limited conclusions so far, because the study's ongoing. 

CRAWFORD: Ok. You mentioned it was surprising to you that there was a greater number of individual White Sharks based on the photo ID work, than you would have expected just based on your observations?

ENARSON: I could say the exact same thing about the Chatham stuff as well. I would have said that I'd maybe seen one Shark each of the first two days, and it turned out to be three or four Sharks. I would have said that I would have seen maybe five on the last day, and there was over ten. 

CRAWFORD: And that was based on distinct morphological patterns from your camera images, yes?

ENARSON: Correct, yes. And you'll have to also understand that when I'm there I am by-and-large photographically focused. So I'm mostly looking at the animals like a shape in the frame, rather than actively working on identifying them. 

CRAWFORD: Yes. And I know from direct experience that when you're in the cage and things are happening - if you're focused through that lens, it is very different than if you are looking at the animal without any types of distractions. 

ENARSON: Absolutely. I have less clear perspective on individuals than the other people around me, because I'm more focused on (a) safety and (b) framing. 

CRAWFORD: Yes. And then it reverses, because after-the-fact when you take a look at the images that you've collected, then you get a very specific sense that other people do not get in real time. I presume you are using high-end photographic cameras as well?

ENARSON: Yep.

CRAWFORD: I don’t know you mentioned it, but I think Peter did ... have you ever been involved with Peter's operation, when you were cage diving in a non-standard way? It seems to me he mentioned something about deploying two cages at one time? 

ENARSON: Yep. We've done two cages, and we have also done bottom cage stuff. 

CRAWFORD: Tell me a little about that, please. What was your experience, first of all with deploying two cages? 

ENARSON: It allows you to get a perspective back on the other cage. So, it is mostly a way to try and get a photo of a Shark interacting with the cage. Which is not a photo you can get from within the cage. The Sharks interact a little bit with the little cage but, by-and-large it's just a different vantage point. The bottom, of course, is categorically different.

CRAWFORD: Before we go to the bottom, did you notice anything that you felt was surprising with that distant perspective back on the first cage?

ENARSON: Not really. 

CRAWFORD: Ok. It was the same thing, but viewed from a different perspective? 

ENARSON: Yes.

CRAWFORD: Ok. Now please tell me about bottom cage diving - was it at the same site off Edwards Island? 

ENARSON: Exactly the same place. 

CRAWFORD: Roughly what was the depth of the cage on the bottom?

ENARSON: Eight to ten metres. 

CRAWFORD: Tell me about your experience with that.

ENARSON: I would say, relative to Australia, which is the other bottom diving place, the Sharks at Stewart Island have been extremely shy regarding a bottom cage. They are not that keen to approach. 

CRAWFORD: Really? What's your thinking on that? What might possibly explain that? 

ENARSON: I think they're just nervous around it, so far. They haven’t had sufficient habituation around it to feel any comfort with it yet. 

2. EXPOSURE TO MĀORI/LOCAL/SCIENCE KNOWLEDGE SYSTEMS

CRAWFORD: In terms of your experience, please characterize the extent to which you have been exposed to the Science knowledge system.

ENARSON: I obtained a degree in Zoology. I was planning to carry on to be a Marine Biologist, but I decided it was not an easy way to make a living. So, I chose to go elsewhere, into Medicine. But I ended up being somewhat involved anyways, just through a comprehensive reading of the world literature, since I have access to the University library. So, I've read everything that's come out. Through my knowledge, I've been involved in a couple of areas. Just being pulled in, because of my knowledge.

CRAWFORD: You said you have a degree - I'm presuming it's a Bachelor of Science - in Zoology?

ENARSON: Correct.

CRAWFORD: When did you get that, and where?

ENARSON: University of Calgary, in 1994.

CRAWFORD: When did you transfer into medical education?

ENARSON: Started in 1996.

CRAWFORD: When did you reach your degree there?

ENARSON: 2004. And then finished fellowship in 2006.

CRAWFORD: Was that as a General Physician, or as a specialist?

ENARSON: Pediatric Emergency Medicine. 

CRAWFORD: Which means you went through the standard medical training, and then you went into additional specialized training? 

ENARSON: Correct.

CRAWFORD: And then you interned?

ENARSON: Yep. 

CRAWFORD: When did you start to practice as a specialist?

ENARSON: 2006.

CRAWFORD: Ok. So, there was some overlap with your cage diving, as you were moving into full medical practice. Perhaps you had some more time and resources to do that kind of recreational diving at that point?

ENARSON: Yes, it has a lot to do with time and resources.

CRAWFORD: Alright. It is clear that you have advanced familiarity and expertise in Science.

ENARSON: Yes.

CRAWFORD: Same question, but this time with regard to Indigenous knowledge systems. To what extent have you had exposure to Indigenous culture and knowledge generally, and Māori culture and knowledge specifically?

ENARSON: Very little.

3. WHITE POINTER DISTRIBUTION AND ABUNDANCE

CRAWFORD: In general, what might your thoughts be with regards to Edwards Island as a potential place for reproduction for White Sharks? Mating in particular? 

ENARSON: I certainly think it's possible, because we've seen at least one mature female with an extremely fresh scar, what would probably be a mating scar. White Sharks are so sex-segregated at an adult level, that if you ever have mature females and males together, it has to cross your mind. 

CRAWFORD: That female you saw with the very fresh wound - was she a large female? 

ENARSON: Yes. She'd be roughly five metres. She had a fresh wound behind her pectoral fin, with tooth marks running down the pectoral fin. 

CRAWFORD: Was there a crescent shape on the pectoral fin itself? 

ENARSON: It was clearly a White Shark bite, yeah. 

CRAWFORD: But I mean, was there a crescent shape to it?

ENARSON: Yeah.

CRAWFORD: Alright. What do you know about White Shark mating, other than the wounding? What's known about it?

ENARSON: I would say it's very, very little. Because there's only one dubious observation, that was ironically in Otago. 

CRAWFORD: What is the dubious observation that you are aware of in Otago? 

ENARSON: It was published in a research symposium about fifteen years ago, and it regards the observations of a volunteer Seal observer describing what sounds like White Sharks mating. But the researchers were unable to make further contact with the observer, so there's no validation of it. But there are no other even descriptions of White Shark mating. You would have to assume it's similar to all other observed Shark matings. So, you can get an idea of what it would be like.

CRAWFORD: Similar in what regards? In terms of behaviour, like the copulation form?

ENARSON: Yes, grasping around the pectoral fins, holding, insertion of claspers. You can imagine it would be broadly similar. 

CRAWFORD: Ok. Getting back to your observation of the large female with the fresh wound ... do you remember, roughly, what time of year that was?

ENARSON: I can find out exactly in just a moment. The date of the photo would be April 13, 2012. 

CRAWFORD: Outstanding, thank you. Had you heard of any other knowledge about where White Sharks might be mating around Stewart Island?

ENARSON: Not a clue.

6. EFFECTS OF CAGE TOUR DIVE OPERATIONS

CRAWFORD: I want you to have the opportunity to express any opinions, if you wish, about the effects of Shark cage dive operations on the White Sharks, and on the possibility of Shark-Human interactions. 

ENARSON: I just sent in an affidavit to the New Zealand High Court having a very strong opinion. So, I think I'm on the record. 

CRAWFORD: Really? I've seen several of the affidavits in those proceedings, but I did not see yours. 

ENARSON: It was sent about a week or two ago. 

CRAWFORD: I've seen Clinton Duffy's, and Allan Munn's. I've seen Storm Stanley's. Alright, I’m trying to be sensitive about this ...

ENARSON: Sure.

CRAWFORD: Maybe this is the best way for me to proceed. Do you have an opinion that you would like to share about the effects of White Shark cage dive operations generally, and in New Zealand specifically.

ENARSON: Yes. I have strong opinions. 

CRAWFORD: Please share them. 

ENARSON: It's a multi-page affidavit, so it ends up being a fairly broad question. But I think the effects of cage diving on White Shark ecology are very, very little. Both from a personal observation standpoint, and from reading all available studies, their appears to be little change not only in White Sharks, but all Sharks studied, with regards to ecological role in the context of the cage diving milieu, if you will. It's been looked at with White Sharks where their migration patterns and ecological role has changed not at all - or very, very little. For example, there was concern from the Australian study, which is always the quoted one, which was noting that the median time spent at the Neptune Islands between two time periods, a decade apart, between which there was an increase in cage diving, that there was a change from a median of 2 days in the earlier time period to 6.5 days in the later time period, but with the caveat that the number of receivers monitoring the Sharks had greatly increased also between the two time periods. So then, looking back at a single common receiver between the time periods, there was a 2-day versus 3-day median. So, the actual time spent at the Island was not very different. The studies all showed habituation in the response of the animals, and they all continued to migrate, to move as they had otherwise. So, I think the overall change in White Shark ecology is very little. There is a study on Tiger Sharks in the Bahamas, which showed that Tiger Sharks tagged in the cage diving region as opposed to ones well-separated, actually migrated broader and spent less time at the site, than ones that were tagged elsewhere. So, there did not appear to be any specific causal relation with the cage diving and Tiger Sharks. There was a Caribbean Reef Shark study that looked at movement patterns of fed versus not-fed Sharks, and they found no significant change in movement patterns of fed individuals. So, I think the ecological effects on White Sharks would be small, if any. The cost to the animal is certainly an open discussion. There's no current studies available on the potential cost to the animal because of cage diving. Charlie Huveneers in Australia is just soliciting research money right now to look at that. So, data might come out in the next few years, but currently not available. There was a study of Whitetip Reef Sharks that looked at their metabolic costs in Shark-feeding tourism situations, and they found a 6% increase in metabolic demands during feeding days. So, what the biological relevance of a 6% change in metabolic rate, or metabolic demand is, is hard to say. There was also a Stingray study from 2008 which raised concerns about large impacts on their health with feeding operations at tourist sites. But the difference between them and White Sharks would be that these were abnormal aggregations, they are solitary animals, and they were being brought into abnormal artificial aggregations, and there was some concern about increased disease and injuries in these animals. Which would be unlikely in White Sharks, considering that the animals are already aggregated at sites, they are not being aggregated by the cage diving. So, it’s hard to say if that’s relevant. The other thing is that I think that the impact on White Sharks is not remotely uniform across the population. I think it’s a small number of animals who have the majority of the interaction with the cage diving boats. Then there is, as you were sort of labelling the Levels 1-4, other animals who have far lesser interaction with the boats. And also I would speculate a large proportion of the population would have no interaction whatsoever with the cage diving. So, any effect on the broader White Shark population would be very, very small - if any. As it pertains to it's effects on Humans, I think there are no effects on Humans. I don’t think anybody has shown any, and I think that any suggestion that cage diving is increasing the risk to Humans, is highly speculative and not very rigorous. 

CRAWFORD: That's quite a bundle. I wasn’t expecting that you had such organization of thought in this regard, in both the issues and your opinions on them. One follow-up question that I think would be an important one ... you made reference to the idea that there are a limited number of animals that will actually engage with the cage dive operation, relative to the number of animals in the population. Getting back to that Level categorization that emerged naturally from my discussions with Peter and Mike, they indicated there have been a very limited number of Level 4 individuals. In the case of White Shark-Human interactions, it needn’t take a large number of White Sharks to have Level 4 interactions with the Humans. Whether you call them 'problem animals' or whatever, the focus is on the behaviour of individual animals that are involved in attacks, rather than on a population abundance scale. You could argue that even though it’s a limited number of animals coming in direct local proximity to the cage dive operation, and perhaps even a more limited number of animals that are exhibiting Level 4 attitude or aggression. How would you respond to that argument? The idea that it doesn’t take many, in order to have a White Shark-Human effect some other place up the coast? 

ENARSON: A couple different ways. First of all, I don’t think the cage diving boats are creating that in those individual Sharks. I think it pre-exists in those individuals. So, I think within a population of White Sharks there are very cautious animals, and there are very enterprising individuals, who will explore every opportunity and are much more willing to interact with Humans. Whether it be fishing, or aquaculture, or cage diving, or recreational fishing. They are much more likely to interact already, and I suspect - although this obviously almost impossible to prove - but I suspect that the inclination to interact with the cage diving boat is pre-existent in the individual, and not created by the cage diving boat. I think you're just exposing a Shark that is the same individual that is likely to approach somebody who has a fish on a line. It’s a Shark that is much more likely to interact with a longline operation. And I think you're just looking at a different, if you will, a different personality in that individual, rather than something that was actually created by the cage diving activity. The other thing I would say is that, nowhere in the world has there been the kind of substantial increase in interaction between Sharks and people, certainly negative interaction, in any area where there's been cage diving - that you wouldn't have assumed already by the increase in water usage

CRAWFORD: Ok. That is a theme that has come up in several of the interviews with the knowledge holders that have participated in this project. One follow-up question specifically in that regard. Would it seem to you that White Sharks have sufficient behavioural complexity to exhibit personalities?

ENARSON: Not a question. There's no question that's true. And although it's not published, well actually it's partially-published ... Neil Hammerschlag had commented on it in one of his papers, how White Sharks in general don't show the same sort of pattern response that you see in Sharks like Blue Sharks, and other animals that interact with boats. They have much more behavioural complexity in their approach to baits, and their interactions around boats. I think even scholarly individuals have noted that a White Shark seems to be sort of a different creature to similar Shark species. I think from anybody who has interacted with them, every White Shark is very different. And on a reliable basis. As I've already commented, there are individual Sharks that won't interact with boats. In South Africa, we know because of their repeated appearance at predatory events, but they won't interact with us. I think it's very difficult to argue that's not an element of personality.

CRAWFORD: If I heard you correctly, it seemed you were reluctant to assign aggression as a component of that personality. Is that the case?

ENARSON: Well, I think aggression is an emotionally-loaded word, which I think can be abused, and it's not necessarily appropriate. I think for a predator that's engaged with a potential prey, I don't know it's fair to call that aggression.

CRAWFORD: But aggression does exist in many non-Human animals, depending on how it's defined.

ENARSON: Yes.

CRAWFORD: Do you think there is an occurrence, no matter how rare in White Sharks, when there could be an individuals that are just more aggressive than others? Without loading up all that human baggage?

ENARSON: Well, I think it must be possible.

CRAWFORD: Do you think it happens?

ENARSON: I'm cautious to say so, because there have been animals that I've encountered, who on one day appeared very aggressive. And I was worried about those individuals, and I was concerned for my safety. But you see them again on a different day, and they're not the same.

CRAWFORD: Please give me an example of that kind of aggression, in that context.

ENARSON: There was an individual in probably 2013 or 2014, who had a huge wound up the side of his mouth that looked like it was caused by a large fishing hook.

CRAWFORD: This is Slash.

ENARSON: This is definitely Slash. I had a lot of problems with Slash. He really did look like he was targeting me. And I needed to be very, very careful to stay away from Slash.

CRAWFORD: Targeting you? In what way?

ENARSON: Oh, I'm partly out of the cage. So the cage is open.

CRAWFORD: Was this when you were in a second cage?

ENARSON Nope. This is in the main cage, and just open the doors.

CRAWFORD: But this was just you in there?

ENARSON: Just me.

CRAWFORD: Peter's running this for you specifically. So, it's under non-standard conditions? And you are taking the risk of having the door half-open?

ENARSON: Yes.

CRAWFORD: So, tell me what happened with Slash?

ENARSON: In several occasions, it really did feel like Slash was waiting for my back to be turned, and would take a run. And he did hit the corner of the cage a few times. It was a little close. But on different days, he wasn't quite the same. So, you get the feeling that Slash was an aggressive individual, but I don't know that I could say it was at personality characteristic.

CRAWFORD: Alright. Ok. This is made even more extreme by the supposed circumstances vy which that particular animal had such a conspicuous wound on it, right?

ENARSON: Yes.

CRAWFORD: Do you know the origin of that wound?

ENARSON: I think it came from research. At least we speculated, because they had been trying to attach tags, and so they were using big hooks to pull the Sharks in.

CRAWFORD: To drill the satellite tag plates into the dorsal fin, as opposed to harpooning the hydroacoustic tags?

ENARSON: Yep. We speculated that he had just been injured in an attempt to tag. But who can say?

CRAWFORD: Right. Speaking of the satellite tags, did you notice those tags, in terms of the animals that you were seeing from the cage?

ENARSON: Yep.

CRAWFORD: Was there any type of pattern across either the type of animal, or their interactions with you or the cage?

ENARSON: Often, I think a tagged animal appears a little more cautious. Like they may have had a bad experience. But that's not universally true.

CRAWFORD: Alright. Is there anything else we haven't discussed or considered in regards specifically to the hypothesized or perceived effects of the cage dive operations on the White Pointers? Ecology, behaviour and or Shark-Human interactions? Is there anything that's missing in our discussion?

ENARSON: Perhaps. I think as it pertains to their behaviour - we touched upon it. I think you see short-term changes in the Sharks' behaviour, but it rapidly habituates. And you start to lose it in those individuals. In the long run, if anything, it's more of a habituation response. The other thing, not so commented on, there's a lot of very very specific accusations from the Locals around Stewart Island about changes in White Shark behaviour that they've witnessed. And a lot of very specific things that they think the cage diving operation has created. Or put another way, that they've had experiences that they're blaming on the cage diving operations.

CRAWFORD: Yes.

ENARSON: I think you'd have to deal with each one individually, but I think that each and every one of those observations, they're describing a very natural White Shark behaviour that is very difficult to ascribe to any cage diving interaction. I'm sure you've heard some of them during your interviews.

CRAWFORD: I've got several interviews with the Islanders, the people that hold those concerns. Yes.

ENARSON: There's anecdotes about seeing more Sharks around the Island. Certainly over the time we've heard that they believe cage diving is attracting White Sharks to Stewart Island, which is biologically implausible. There's no way that White Sharks are migrating from the east coast of Australia and from South Pacific islands to Stewart Island, because of some knowledge of a cage diving boat. That's biologically impossible from the start. There are anecdotes about fishermen that have had Whites Sharks ... this won't be a direct quote, but almost "jumping into their boats chasing fish." It's not very plausible that this is a learned behaviour that White Sharks have had from cage diving boats. Around the world, if you have a fish on a line, and you pull it past a Shark - it's going to chase it. This is hardly something that was created by these cage diving operators. One of the big ones is that they claim that Sharks are following the cage diving boats back into harbour. And again, this is nearly biologically implausible. What we know about a White Shark's cruising speed and migrating speed, and the speed of the boats returning to harbour – it makes very little sense that a White Shark would or could follow that boat over that distance back from Edwards Island. The average cruising speed of a White Shark, from migrating Sharks, is somewhere between five and eight kilometrs per hour. Now a White Shark can have higher speeds than that, higher swimming speeds. But their ability to sustain them would be questionable, over the eight or ten kilometers that it takes to get back to Oban. And the motivation of a Shark ... I think anybody who spends time with the Sharks around Edwards Island, or any cage diving site, knows that their interest in the baits is rather transient, and not very strong. The fact that a Shark would expend tremendous energy to sustain much greater than cruising speed to make it back to Oban - is actually somewhat ridiculous. So, it's not very plausible, that accusation. Especially when the boat is no longer providing any bait stimulus. It would mean that the Shark is really attracted to the boat specifically, which is not a very plausible claim.

CRAWFORD: Why do you think that's not plausible?

ENARSON: White Sharks don't usually follow boats. It's a behaviour that has been described in some oceanic species, where they're following boats that are dumping garbage. But I've never heard that description for any White Shark, anywhere on the planet. The Sharks don't appear extraordinarily motivated around the cage diving boats. So the fact that they would expend that tremendous energy to simply follow the boat - it's not very likely.

CRAWFORD: Ok. I think I understand what you're getting at. Last question. You kind of brought it up one way directly, and in another way indirectly. You said something to the effect that White Sharks are in a class of their own. I want to dig in just a little bit on that, specifically about intelligence. What do you know, either from your own personal observations, or as a person who is familiar with the Science knowledge system, about the intelligence of White Sharks. In particular, their ability to learn and behave in complex ways.

ENARSON: This is a tough area. Because from a purely anatomical standpoint, the areas of the brain that are typically associated with higher cognitive functions, are actually smaller in White Sharks than in some other species. Generally the species that live in complex social groups, something like a Scalloped Hammerhead or what we call Carcharhinid Sharks that live in bigger groups. They have much larger areas of the brain that are typically associated with higher cognitive skills. But, from an actual street-level-with-the-Sharks perspective, they appear to be capable of quite a lot of problem-solving. They do appear to learn. Especially in a hunting context, they appear to be able to acquire skills and fine-tune their approaches in ways that suggest quite a higher intellect.

CRAWFORD: Can you give an example of that?

ENARSON: Well certainly, everybody speculates that around baits, just as an example, the White Sharks will change their tactics. If something's not working, they'll try something different. And then they'll use the best and most successful techniques in the future. But again, I'm not sure if that's true or not. But certain individuals, in a hunting context which I think is a lot purer way to look at it, have techniques that make them more successful than in other animals. Since we're able to see the same individual's hunting experience year-to-year, you can see that some animals use more sophisticated techniques, and seem to have more success as a result. Again, quite anecdotal.

CRAWFORD: No, no. That's fine. Final, final question then. What have you heard, or learned, regarding the possibility of White Shark complex inter-individual social behaviour at the level of family or otherwise?

ENARSON: That's perhaps a more complex question than you intended. There's multiple levels to this. I think when you get to see White Sharks on a regular basis ... especially in Australia, they're working on some research to identify White Shark clans, which are certain individuals that always appear to arrive at the same time, leave at similar times. So they seem to have relatively consistent social interactions between individuals. They don't hunt together. They don't school together. But there seems to be a familiarity between those individuals that they have labelled 'clans.' And when you see two Sharks that are from the same clan, there's a lot more relaxation in the behavioural interactions, then there are when an unfamiliar animal arrives. So certainly, it would seem that Sharks are able to recognize familiar individuals, and that they develop some familiarity in the interactions, so that there is less tension between known individuals, versus unknown individuals. On an anecdotal basis strictly, of course. To the second half of that question, White Sharks clearly appear to have a language based on postures and different sort of movements that they make. Even as a Human, you can learn to recognize those, and as a diver you are certainly well advised to, in order to stay out of trouble. Because they certainly have threat postures, certain threat displays that you need to learn to recognize. And they use them to each other as well.

CRAWFORD: Yes. For example, based on your experience, what's a rather stark and obvious posturing that you have seen like that?

ENARSON: From personal experience, and I think there are other experienced people who would agree, there's almost a grade of threat display that you need to recognize. Certainly a fairly early display of tension is when they hunch their back, they drop their pectoral fence, and they swim in a sort of exaggerated manner. That communicates a level of elevated stress for the animal. But when the animal drops its top jaw, in front of you or another animal, that's a far more acute and far more high-level threat display.

CRAWFORD: Have you seen those in your diving experience?

ENARSON: Oh, absolutely.

CRAWFORD: Consistently from males? Females?

ENARSON: No, I wouldn't say it's consistent to one gender.

CRAWFORD: Were there any other circumstances that might have been associated with those threats?

ENARSON: Obviously, we're limited by our ability to observe the animals. We can only see, say 30 metres from our cage. But within our situation, certainly when the Shark appears uncomfortable with you, he can make these threats. But they also make them to each other, when the animals get too close to each other.

CRAWFORD: Right. Ok. You brought something up there that triggered something else. Are you aware of any evidence of larger White Sharks swimming with smaller White Sharks?

ENARSON: It depends what you mean by 'swimming with'.

CRAWFORD: I don't mean animals responding to a common stimulus, an aggregation where there's something like a berley trail or a dead Whale carcass. I mean out there, where the animals are swimming and maintaining formation, basically. Based on positive social interactions.

ENARSON: No. I mean there's been aerial observations of White Sharks interacting. But they're so single and so anecdotal, they're hard to pull together.

Copyright © 2020 Mark Enarson and Steve Crawford