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Showing posts with label Conditioning of Sharks. Show all posts
Showing posts with label Conditioning of Sharks. Show all posts
Let's not forget
the impact of the thousands upon thousands of people who feed and condition Sharks and other Fishes on a
daily basis, i.e. the fishermen and spearos!
Case in point:
And this is being repeated, mutatis mutandis, countless times wherever there are fishermen = all the time and everywhere! Do you really believe that the incremental effect of a few dozen
Shark feeding operators is in any way relevant to the health of
Elasmobranch populations?
Now watch, and listen = it's exactly like I said back then, and the impact of our industry is absolutely irrelevant.
The romantic in me says it's LURVE. The cynic says the shark is assuming that position to have ectoparasites removed - and simply following what it takes to be the ecto-parasite-removing creature when it retreats.
I think this shows how we, as hug-loving mammals, are hard-wired to misinterpret what is presumably going on - and hence how easily the idiots (Ritter, Treadwell et al) can go off the transcendental deep end.
Yes and no!
Clearly, those are conditioned Sharks that as a minimum have been
habituated to humans insofar as they appear to have lost their natural
fear of them. This is one of the known side-effects of provisioned Shark
dives that when they are conducted responsibly, leads to less agonism = defensive aggression - the flip side being that the resulting familiarity can lead to the well-known problems with those infamous beggar Sharks, hence the need for good protocols.
So yes those Sharks may well want to get cleaned.
Jimmy did show me equally amazing footage of Lemons snuggling up to divers at the Tiger Beach cleaning station, and equally only being rewarded with a friendly rub. Both Jimmy and Cristina have removed squillions of hooks, and the Sharks may indeed regard, and thus seek them out as some sort of cleaner organism as a consequence.
But maybe it's something else?
Specially in the case of Cristina that induces a trance-like state (not tonic!) by stimulating the Sharks' snout, the Sharks may simply come in for the resulting, obviously pleasurable sensation. Does that equal LURVE and affection and the like? Methinks not, it may be more akin to us, ahem, visiting a brothel - but it is totally amazing nevertheless!
And now?
Does this mean that we should all swarm out and start giving Sharks affection, or whatever, by conditioning them to come in and get petted?
Is it not enough to "witness" these animals in all their grace and
elegance? Do we need to touch them and ride them as well? Do
photographers really need to shoot inside a Tigers mouth? Do we need to throw pokey-sticks at them? Where does it end, where do we call the game and set the safety goal posts?
And for me, the answer is crystal clear.
Like I never cease to repeat, Shark dives need to be regarded as
wildlife encounters and subsequently, conditioning needs to be kept at
an absolute minimum = limited to attracting otherwise shy species, and ensuring the necessary degree of safety. All else is just simply unwarranted and often disrespectful showmanship that benefits only the human, with only more risks for the animal.
Cristina and Jimmy of course get a pass.
Mind you, this not because of what they do but because of who they are!
The other molesters, not so much - but once you've logged thousands of Shark dives, devoted your life to Shark conservation but above all, removed hundreds of hooks, you too will be entitled to some rather superfluous, and clearly not reciprocated SharkLURVE - petting, scratching, hugging and kissing included!
I could not agree more - including the fact that there is a local effect, this however not so much precipitated by the bait that is actually all being eaten and mostly leaving Shark Reef in the stomach of the Bulls.which do not reside there. For them, those Tuna heads are just a snack, and not very nutritious at that, and I have no doubt that they continue to prey naturally and fulfill their ecological role in their habitat.
Like I said elsewhere, we are very mindful of our impact and have completely stopped any indiscriminate dumping of bait a long time ago. As a consequence, the composition of the Fishes has changed from a rather low species count of 260 that was being dominated by small scavengers and predators, to now 480+ that is highly representative of any (non-fished) fringing reef along one of Fiji's principal islands.
The effects I detect are more behavioral.
Juerg is writing a paper on the subject, so I don't want to preempt his findings on the subject, the more as I'm yet to see any draft.
But apart from the obvious conditioning whereby we are actively teaching our Sharks to behave in certain ways, I believe that I'm observing inter-specific aggression all the way to competitive exclusion among the various Sharks. And also believe that we've interfered with the diel patterns of at least the Whitetips that are usually crepuscular but on Shark Reef, leave their hidey holes to come and feed at midday.
But at this stage, I'm obviously speculating, and Juerg will also need to answer the question of so what - even if there's an effect, does that necessarily mean that it is bad?
Anyway, thank you Helen!
Her endorsement is far from trivial.
For years, Shark provisioning has been the target of much skepticism from researchers and NGOs alike, and only recently do I detect a slight shift in positions away from outright hostile to at least benevolently intrigued. This is largely due to the realization that baited Shark tourism, whilst certainly presenting its specific challenges (especially when conducted poorly!) is never the less years ahead of the alternative = Shark fishing.
And recent research is also showing that whilst local, hitherto unqualified and unquantified effects persist, effects at large temporal and spatial scales are negligible.
Sharks, it appears, are just different.
Whilst bony Fishes show all the typical negative effects of conditioning that lead to the well known numerous bites by Groupers, Moray Eels all the way to those notorious swarms of pesky Sergeant Majors, Sharks simply don't do that - that is, provided that who feeds them does so responsibly, see the reports about beggar Sharks from, say, Tiger Beach!
Long story short?
Come and see for yourselves - this is still the top season for high numbers!
This pic by Doug is so good that I catch myself using it time after time again - click for detail!
Finally!
Stating that I'm mighty proud would clearly be the understatement of the year!
Opportunistic Visitors: Long-Term Behavioural Response of Bull Sharks to Food Provisioning in Fiji
Juerg M. Brunnschweiler, Adam Barnett
Abstract
Shark-based tourism that uses bait to reliably attract certain species to specific sites so that divers can view them is a growing industry globally, but remains a controversial issue. We evaluate multi-year (2004–2011) underwater visual (n = 48 individuals) and acoustic tracking data (n = 82 transmitters; array of up to 16 receivers) of bull sharks Carcharhinus leucas from a long-term shark feeding site at the Shark Reef Marine Reserve and reefs along the Beqa Channel on the southern coast of Viti Levu, Fiji.
Individual C. leucas showed varying degrees of site fidelity. Determined from acoustic tagging, the majority of C. leucas had site fidelity indexes greater than 0.5 for the marine reserve (including the feeding site) and neighbouring reefs. However, during the time of the day (09:00–12:00) when feeding takes place, sharks mainly had site fidelity indexes smaller than 0.5 for the feeding site, regardless of feeding or non-feeding days Site fidelity indexes determined by direct diver observation of sharks at the feeding site were lower compared to such values determined by acoustic tagging.
The overall pattern for C. leucas is that, if present in the area, they are attracted to the feeding site regardless of whether feeding or non-feeding days, but they remain for longer periods of time (consecutive hours) on feeding days. The overall diel patterns in movement are for C. leucas to use the area around the feeding site in the morning before spreading out over Shark Reef throughout the day and dispersing over the entire array at night. Both focal observation and acoustic monitoring show that C. leucas intermittently leave the area for a few consecutive days throughout the year, and for longer time periods (weeks to months) at the end of the calendar year before returning to the feeding site.
So this is it.
Like we never tire to say, BAD has essentially been established in order to manage a Shark research and conservation project and consequently, everything we do is geared towards those aims whilst generating just enough income to compensate the various stakeholders and ensure our long term survival.
So far so good - touch wood!
But of course the beginning was everything but easy.
I had reached out to Gary Adkison when formulating the Fiji Shark Project, and when Juerg lost his Bull Shark research site in the Bahamas, Gary suggested that he go check out the crazy dude who was trying to set up a Shark MPA in Fiji. I desperately needed to find a conservation-oriented researcher, something that in those times was far from common; and Juerg desperately needed to find a new and and above all, reliable Bull Shark research site for his Bull Shark Tagging Programme. We met, took each other's measure, liked what we saw and decided to give it a try.
Gesagt getan and the rest, as they say, is history.
That was in 2003.
Ten years and countless adventures, discussions and heated debates (!) later, I must really say that it was a match made in heaven. I really, really like and respect Juerg and the feeling is likely reciprocal, the more as we really completely see eye to eye on conservation matters (sometimes less so on research techniques), are completely result-driven and despise bullshit - and we even share the same degree of incisive humor!
But I'm digressing as always.
Back then, Shark conservation was very much in its infancy and the exclusive domain of a handful of idealistic and rather clueless loons (and probably still is!), we were both essentially rookies, and progress only happened in baby steps and with plenty of setbacks. This also on the research side where the first generation of PAT tags was rather temperamental and where for ethical reasons, we had burdened ourselves with the challenge of trying to tag the animals underwater, first intra-gastrically and then externally.
But Juerg and Gary did persevere and eventually got it done - and this very much despite the vocal objections of your truly who developed an increasing distaste for the invasive techniques.
Love you guys! :)
At the same time, we started our long term monitoring.
This is a first (and by no means last!) look at our enormous data base where we have so far meticulously recorded close to 10 years, or approx. 4,000 individual baited Shark dives in the Shark Reef Marine Reserve. Over those years, we have named and monitored more and more individual Sharks and have been keeping particularly detailed records of presently approx 150 individual Bulls.
The paper is the comprehensive analysis of only one subset of those observations, i.e. simple presence/absence data, this in comparison to several years' worth of acoustic tagging data of the same 48 individual Sharks.
This particular Shark dive has been operating continuously since 1998 and it is fair to state that if there has ever been a population of conditioned Sharks, it would be the Bull Sharks of Shark Reef.
And yet,
Our Bulls remain wild animals. Once they have discovered Shark Reef, they do come back; but at the same time, it is quite obvious that they continue to roam the area and undoubtedly fulfill their ecological function like any other non-provisioned Bull Shark, much in line with what we postulated years ago - and now we have the peer-reviewed science to back it up!
Effects at large spatial and temporal scales appear minimal. This is consistent with all research into provisioned Sharks, i.e. that there may well be conditioning on site but that typically, the long term migrations and life history in general remain largely unaffected.
Feeding does not appear to significantly effect the Sharks' diel patterns, this with the only exception that they will spend more time at the feeding site on feeding days - however only to depart and continue their usual daily roaming patterns. Note the observation about night-time foraging at and possibly even within the Navua River - very interesting and eminently testable!
Same-same for their propensity, or lack of, to approach humans. There are obviously pronounced differences at the individual level, something I experience on a daily basis - but despite of the fact that there are Sharks that are decidedly more friendly (or bold), it is equally true that none of them comes begging for food when there is no bait in the water. In fact, the observation that during the time of the day (09:00–12:00) when
feeding takes place, sharks mainly had site fidelity indexes smaller
than 0.5 for the feeding site, regardless of feeding or non-feeding days may be an indication for the fact that the presence of bait barely compensates for the notorious shyness of this species!
Long-term exposure to feeding does not appear to cause any conditioning in terms of dependence on that food source. One could stipulate such conditioning if the data showed increased presence over the years - but the fact is that the data appear to absolutely negate that hypothesis, as e.g. illustrated by the site fidelity indexes for 2004-2011 of Crook, a friendly old-timer and voracious hand feeder., to wit 0.48, 0.20, 0.16, 0.24, 0.23, 0.22, 0.14 and 0.47 (Table S1), an observation that is consistent for all monitored Sharks.
The Shark Corridor appears to confer a solid degree of protection. Yes the animals do regularly leave that area - but site fidelity indexes that are larger than 0.50 indicate that the protected area is apparently large enough to have a positive effect.
Long story short?
Granted, strictly speaking, this only applies to Fiji Bull Sharks that are being fed in Fiji and not to "Sharks" in general - but after Aleks' paper on Caribbean Reefs and Neil's Tiger Shark paper, we now have one more indication that one cannot simply draw conclusions from other research showing conditioning, and possibly negative consequences for other species: not from those Lemons in Moorea, not from the Southern Stingrays in Cayman - and certainly not from teleost Fishes that appear to have a higher propensity for being conditioned, let alone the proverbial bloody Bears!
On the contrary and with the caveat that this may well be species- but possibly also situation-specific (see the Moorea Lemons where there may be procedural issues), it appears that those larger Sharks may just be a tad too smart for the simplistic cause-effect bullshit spouted by our detractors.
In fact when it comes to the risk they pose to humans, I'm of the strong opinion that provided that those baited dives are conducted responsibly, those "tame" Sharks pose less and not more of a threat! Yes I'm obviously speculating - but after thousands of Shark dives, I've earned myself the right to do so!
And their long term life history?
If there there is one constant observation among all papers
analyzing Shark provisioning, it is that over the longer term, the
animals keep their normal migration and mating/birthing patterns - e.g.
think of the GWS in Lupe, the Playa Bulls and the Bimini GHH that are all seasonal irrespective of the fact that they are being fed! This is once again a strong indication that feeding causes no harm, at least not to the Sharks that are being fed.
Anyway - is this cool, or what!
Keep watching this space.
As I said, this is only the beginning, meaning that our data base contains the answers to many more questions. And, we're already conducting and are about to roll out several more new large multi-year projects that will hopefully lead to new important insights - especially about reproductive and possibly even natal philopatry that would greatly assist us in refining local Shark conservation measures.
I must say, I really did like this.
Check it out - hat tip: Underwater Thrills.
My call?
This controversy will never go away and it is good for us not to divert and obfuscate but to tackle it head on instead, like Mark Addison does truthfully and I find, rather brilliantly.
The opposition is of course spot on.
We do aggregate Sharks and we obviously docondition the Sharks to lose some of their fear of humans, both of which can obviously lead to more and closer interactions and thus, conceivably but not at all necessarily as they are getting "tamer", to a higher likelihood of Shark strikes.
That's both a fact and also, painfully trivial.
But that is of course not the whole story.
Please re-read this - I mean, the stuff between the rant at the beginning and the rant at the end. :)
Anyway, the long story short is that I believe that Shark baiting (and outright feeding like we do) is neither inherently Good, nor that it is inherently Bad. It can be either, and this very much based on how it is being done - and when it comes to that,there's certainly the Good, the Bad and the outright Ugly, and I spare you the links!
Fiji?
We here really do spend an inordinate amount of time on always re-evaluating our protocols and obviously believe that we're doing it right - this always under the premise that we do want to attract the Bull Sharks which are extremely shy, and that so far, the scarce peer-reviewed science on the subject has failed to conclusively show any harm that provisioning is inflicting on the animals.
Should the latter change, we will change our procedures - and that's a promise.
And what about the enhanced risk of Shark strikes?
That obviously remains a distinct possibility, at least in theory - but if things are conducted responsibly, it is so low to be really negligible. The Fact is that there are NOT more Shark strikes in the vicinity of baited Shark dives. The overwhelming majority of Shark strikes occur completely elsewhere and are being triggered by completely different circumstances, two of the principal ones being people splish-splashing at the surface and spear fishing.
I must say, I really did like this.
Check it out - hat tip: Underwater Thrills.
My call?
This controversy will never go away and it is good for us not to divert and obfuscate but to tackle it head on instead, like Mark Addison does truthfully and I find, rather brilliantly.
The opposition is of course spot on.
We do aggregate Sharks and we obviously docondition the Sharks to lose some of their fear of humans, both of which can obviously lead to more and closer interactions and thus, conceivably but not at all necessarily as they are getting "tamer", to a higher likelihood of Shark strikes.
That's both a fact and also, painfully trivial.
But that is of course not the whole story.
Please re-read this - I mean, the stuff between the rant at the beginning and the rant at the end. :)
Anyway, the long story short is that I believe that Shark baiting (and outright feeding like we do) is neither inherently Good, nor that it is inherently Bad. It can be either, and this very much based on how it is being done - and when it comes to that,there's certainly the Good, the Bad and the outright Ugly, and I spare you the links!
Fiji?
We here really do spend an inordinate amount of time on always re-evaluating our protocols and obviously believe that we're doing it right - this always under the premise that we do want to attract the Bull Sharks which are extremely shy, and that so far, the scarce peer-reviewed science on the subject has failed to conclusively show any harm that provisioning is inflicting on the animals.
Should the latter change, we will change our procedures - and that's a promise.
And what about the enhanced risk of Shark strikes?
That obviously remains a distinct possibility, at least in theory - but if things are conducted responsibly, it is so low to be really negligible. The Fact is that there are NOT more Shark strikes in the vicinity of baited Shark dives. The overwhelming majority of Shark strikes occur completely elsewhere and are being triggered by completely different circumstances, two of the principal ones being people splish-splashing at the surface and spear fishing.
May Monsieur Mourier have an agenda?
Check out his pre-emptive statements about Shark feeding here.
Then, compare to excerpts of this new paper he has co-authored.
Behavioural response of the sicklefin lemon shark Negaprion acutidens to underwater feeding for ecotourism purposes Eric Clua*, Nicolas Buray, Pierre Legendre, Johann Mourier, Serge Planes *Email: EricC@spc.int
ABSTRACT: The feeding of marine predators is a popular means by which tourists and tour operators can facilitate close observation and interaction with wildlife. Shark-feeding has become the most developed one around the world in spite of its controversial nature. Amongst other detrimental effects, the long-term aggregation of sharks can modify the natural behaviour of the animals, potentially increase their aggression toward humans, and favour inbreeding. During 949 diving surveys conducted over 44 months, we investigated the ecology and residence patterns of 36 photo-identified adult sicklefin lemon sharks (Negaprion acutidens). The group contained 20 females and 16 males. From this long-term survey, we identified 5 different behavioural groups that we described as “new sharks” (7), “missing sharks” (4), “resident sharks” (13), “unpredictable sharks” (5) and “ghost sharks” (7). In spite of in-and-out movements of some males and females, probably related to mating, the general trend is that residency significantly increased during the study, particularly in males, showing a risk of inbreeding due to the reduction of shark mobility. Intra and inter-specific aggression was also witnessed, leading to an increased risk of potentially severe bites on humans. Our findings suggest the need for a revision of the legal framework of the provisioning activity in French Polynesia, which could include a yearly closure period to decrease shark behavioural modifications due to long-term shark-feeding activities.
From the paper
INTRODUCTION
Large predators, which are potentially dangerous to humans and often feared, account for a substantial proportion of ecotourism activities based on animal sightings.However, because of their generally elusive nature and locally low population densities, such predators are often difficult to observe. Sharks are shy animals (Bres 1993), and provisioning is necessary to produce reliable and impressive aggregations of animals. The last decade has seen tremendous development of ecotourism based on the sighting of top marine predators (Orams 2002, Topelko & Dearden 2005). The practice of shark-feeding is widespread throughout the tropical and subtropical seas of the world, e.g. in the Bahamas, Fiji, South Africa, Australia and French Polynesia, and it is becoming controversial, with little consensus about how it should be managed.
Deliberate and long-term shark-feeding is suspected to generate problems for both animals and humans (Dobson 2006, Newsome & Rodger 2008).It may alter the natural behavioural patterns of sharks, generating biological (for the animal themselves) and ecological (for the ecosystem) effects. Provisioning may cause habituation to human contact and increase aggression towards humans by associating divers with food (Burgess 1998, Orams 2002). However, feeding wildlife can be a positive tool for assisting in the conservation of vulnerable and endangered species, through attaching economic value to wildlife and educating tourists about the need for conservation (Bookbinder et al. 1998, Halpenny 2003); it can also increase the probability of a shark encountering a partner as a result of aggregation (Orams 2002).
Despite the controversy, few, if any, comprehensive reports have measured the impact of shark-feeding, which is now widespread and growing around the world. To date, studies have been conducted on the effect of chumming on white shark Carcharodon carcharias in South Africa (Johnson & Kock 2006, Laroche et al. 2007), as well as sandbar Carcharhinus plumbeus and Galapagos C. galapagensis sharks in Hawaii (Meyer et al. 2009).These studies all concluded that moderate levels of provisioning of cage-diving ecotourism probably had a minor impact on the behaviour of the sharks and no risk of increased attacks on humans in adjacent areas.
In South Africa, Johnson & Kock (2006) showed that conditioning only arises if white sharks gain significant and predictable food rewards, which only happens if operators contravene permit regulations prohibiting intentional feeding of sharks.White sharks are lured to the boat with baits (typically, mashed sardines and fish oil; Laroche et al. 2007) that are significantly different from their usual prey in the area, Cape fur seals Arctocephalus pusillus pusillus (Ferreira & Ferreira 1996).
In Hawaii, Meyer et al. (2009) showed that cage-diving activities did not increase the number of attacks on humans, probably due to the fact that the shark tours use a small amount of fish scraps, mimicking the activities of crab fishing vessels which have been operating in the same area for over 40 yr. In both cases, while some food is used to attract sharks to the cages for observation and photography, the quantities involved are small, so this activity cannot be considered as real ‘provisioning’.
Light baiting is also used at Aliwal Shoal (South Africa) for attracting tiger sharks Galeocerdo cuvier and allowing encounters with snorkelers in open water (Dicken & Hosking 2009).
However, the available scientific data focus on the economic value of the recreational activity, and do not address its effects on the behaviour of these potentially dangerous sharks (ISAF 2010).Bull sharks Carcharhinus leucas, another dangerous species (ISAF 2010), have been attracted to an ecotourism site in Beqa (Fiji Islands) since 2002 through a real feeding and conditioning process based on the release of several tuna heads during each dive (E. Clua pers. obs.); here again, however, the only data provided are socio-economic (Brunnschweiler 2010), with no reference to the biological issues of provisioning of carnivorous animals.
Given the controversial nature of shark-feeding, there is a critical need for empirical studies that focus on potentially dangerous sharks, and address both the potential disruption of their natural behaviour, which underpins their resilience, and the increasing risk of fatal attacks on humans (Garrod & Wilson 2006).
In French Polynesia, sharks are fed daily during diving activities.The main species involved, the sicklefin lemon shark Negaprion acutidens, can reach over 3 m in length and is considered to be potentially dangerous to humans (Maillaud & Van Grevelynghe 2005, ISAF 2010). This coastal shark is widely distributed in the Indo-Pacific, from Eastern Africa to French Polynesia. However, very little is known about the ecology of the sicklefin lemon shark in the Central Pacific. Despite its commercial value (Compagno 1984), only a few studies have been conducted in the Indian Ocean (Stevens 1984) and in Western Australia (White et al. 2004) besides a recent global genetic study (Schultz et al. 2008). The ecology of its sister species, the Atlantic lemon shark N. brevirostris, has been well documented during past decades (Gruber 1982, Chapman et al. 2009), mostly in the central Western Atlantic Ocean. However, while its early life has been extensively studied (Morrissey & Gruber 1993, DiBattista et al. 2007), very little is known about the adult stages of N. brevirostris and even less about N. acutidens.
Moorea Island (French Polynesia) is among the few locations worldwide where it is possible and feasible to have daily encounters with several wild adult sicklefin lemon sharks in their natural environment. This characteristic provided us with an opportunity to investigate the behaviour and residency pattern of an adult population of this reef shark species through daily underwater observations at a provisioning tourism location. Here, we describe the population size and structure of this species, aggregated for ecotourism purposes at a site on the northern outer reef of Moorea Island. We divided the population into co-occurrence groups and describe the residence patterns and behaviour of these groups. We also tested the hypothesis that shark-feeding increases the fidelity of lemon sharks to the site, and discuss the potential long-term effects on population resilience and behaviour, including the risk of increased interactions with humans. From the
DISCUSSION
….Assuming similarity in the natural behaviour of these 2 sister species (Editor: Common and Sicklefin Lemon Sharks), our findings could be linked to an aggregating effect of shark-feeding, which decreases the mobility of animals, mainly the males, and may contribute to increased inbreeding. This trend may lead to long-term loss of genetic variability in the Polynesian lemon shark populations, even though natural philopatry in N. acutidens, which would have been a detrimental factor, seems to be low (Schultz et al. 2008).
Increasing residency was a general trend for the shark population. For all groups except Group B, which was composed of animals that disappeared, the linear regressions had positive slopes (Fig. 4), indicating an increase in shark abundance over time, and their site fidelity increased over the 44 mo, particularly for the ‘resident’ subgroups, C1 and C2 (Table 1). This means that, despite some sharks leaving and othersarriving, the number of days with sharks present and the number of sharks at the site both increased. This trend is explained by the increased attraction of sharks by provisioning, suggesting that learning plays a strong role in optimising their food search (Guttridge et al. 2009). Our findings are consistent with similar situations where other elasmobranchs (rays) learned to associate specific locations with food rewards, with detrimental effects on their behaviour, and indirect effects on the surrounding marine ecosystems, leading to the concept of an ‘ecological trap’ (Corcoran 2006, Gaspar et al. 2008, Semeniuk & Rothley 2008).
In the case of lemon sharks, their increased site fidelity can have a negative effect on gene flow, as mentioned previously, and can also affect their role as top predators in the area, as shown for top terrestrial predators such as dragons Varanus komodoensis in the Komodo National Park, where provisioning was eventually banned (Walpole 2001).
Among the negative effects, we observed intraspecific interactions generated by the provision of a limited amount of food. Not all sharks present during a dive acquired food, and this resulted in exacerbated competition among the animals. This pattern can lead to increasing the number of intraspecific dominance actions and the aggression of sharks to acquire food (Ritter 2001), as shown for rays (Semeniuk & Rothley 2008). Dominance is often driven by the size (length) of the sharks in social groups (Allee & Dickinson 1954, Myrberg & Gruber 1974). During several feeding sessions, the largest resident male, M04, appeared to be the most inquisitive, approaching the divers closer than any other individual did. Since males M07 and M18 were dominant in 2005, M04 definitely acquired increasing dominance behaviour with respect to other individuals, which turned into deliberate aggression towards other males when several of them were present.As was previously observed in 2005 for its 2 predecessors, from 2006 onwards M04 often arrived in the morning with fresh scars or notches that can be attributed to intraspecific fights (N. Buray pers. obs.). Aggression increased significantly when resident males came back to the feeding site after the mating period, probably in the context of a reorganisation of the hierarchy, as shown by serious wounds on males that were quite different in their severity and locations from those inflicted on females during mating (Fig. 5).
In natural conditions, sicklefin lemon sharks cannot be considered a gregarious species (Stevens 1984), except during the mating period, and animals usually feed separately.Therefore, intraspecific aggression linked to the feeding process, even though natural among carnivorous animals, can be interpreted as deviant behaviour, exacerbated by human activity.Although managers may consider this process of increasing intraspecific aggression to be acceptable among sharks, it represents a real issue regarding the safety of divers for whom the risk of accidental bites has increased critically (Burgess 1998).Between 1979 and 2001, 47% of shark bites in French Polynesia were experienced in the context of shark-feeding activities (Maillaud & Van Grevelynghe 2005). Although anecdotal, this was confirmed by a serious bite by shark M04 on the left hand, which was not holding any food, of the diver doing the feeding in January 2006 (N. Buray pers. obs.).
The results of this study indicate that in spite of the provisioning activity, several male and female sicklefin sharks seem to have left the study site while others came back to it for mating.This positive aspect from the perspective of maintaining gene flow between this shark population and adjacent ones is mitigated by the increasing pattern of residency for the overall population during the study. At present, the population seems to be a balanced mix of resident and non-resident individuals, which favours population mixing. However, if the resident sharks increase their numbers and their attachment to the feeding site, group living can generate costs for animals which are normally solitary foragers, such as injuries, predation, increased stress hormone levels and exposure to parasites due to increased transmission rates between individuals (Semeniuk & Rothley 2008).If supplemental feeding can be perceived as an artificial support to sharks by providing easy-to-access resources (Milazzo et al. 2006, Laroche et al. 2007), and can allow increasing energy allocation to other fitness-related activities such as rest and reproduction (Orams 2002), long-term unnatural aggregation can also have long-term fitness consequences for the population. Because the studied population is small, daily aggregations at the same location could result in increased social interactions and increased mating between close relatives, reinforcing the risk of inbreeding. As lemon sharks are known for their polyandry (Feldheim et al. 2004), the potential negative effect on gene flow linked to the increasing residency pattern might be buffered by the multiple paternity process; this needs to be thoroughly monitored.
This factor, added to the development of aggression and incremental risk of accidental bites to divers, should lead managers to seriously consider a revision of the regulations on shark-feeding in French Polynesia in order to reduce these risks.An annual cessation of the feeding activity for several months, preferably encompassing the mating period, is an obvious solution.Whereas our study allowed us to draw these preliminary conclusions, additional field investigations are required to better understand the long-term effects of provisioning on shark populations. Further work may also enable us to better understand the risks induced by feeding predators.
Hmmmmmm…
Quick ‘n dirty assessment: interesting - but both prejudiced and highly speculative!
But first things first: this is what I like.
Scientists are finally discovering the Shark feeding industry and publishing a first set of baseline studies, of which this is a (I believe: rather poor) example. And although I do not concur with the conclusions, see below, I do commend the authors for having taken the time to compile and analyze a long term set of data. As the always brilliant CJA Bradshaw remarks, monitoring has long been the ugly cousin of the fashionable experimenting and is only now being recognized as an invaluable tool for trying to decipher complex systems where causal relationships are not immediate and thus difficult to manipulate selectively.
Which brings me straight to my principal critique.
Where is the control group, as in a comparable group of Lemons that are not being fed? If they got nothing to compare them to: how can the authors postulate that any of the described phenomena are caused directly by the human interference and not due to chance variability, or to natural fluctuations in population, or to climate fluctuations like ENSO or the like?
But let’s quickly examine the allegations.
The observed increased residency may lead to reduced gene flow and inbreeding.
Indeed, maybe! But many Shark species, among which Lemons, do wander off during mating season and indeed, so did the studied animals! The increased residency during the remainder of the year is utterly irrelevant in terms of gene flow as the animals do not mate during that time – or are we to believe that Lemon Sharks may engage in protracted dating prior to having sex?
Plus – was the increased residency the direct consequence of the feeding, see above?
Increased intra-specific aggression.
Here, the authors blame the limited amount of food leading to exarcerbated competition; and on the other hand, they seem to postulate (?) that a higher concentration of resident Sharks led to more hierarchical fights and subsequent wounds in males.
Probably! But having witnessed how fast Sharks recover from horrific wounds contracted during the mating season, what is the point? Did any of the bitten Sharks die or end up being permanently inconvenienced as a consequence - and how does that compare to the “natural” mortality and/or bite frequency of non fed Lemon Sharks?
Plus, what’s that tale about M04? M04 often arrived in the morning with fresh scars or notches (that were hence not contracted during feeding time!) that can be attributed to intraspecific fights (N. Buray pers. obs.). Interesting – but is it science?
Knowing that all individual Sharks have different characters: was he maybe just a notorious brawler – and not a very successful one since it was him, the supposedly dominant Shark, coming back with those wounds and not his assumed victims? And who did he brawl with: females or males?
Increased inter-specific aggression - what is the other species: humans?
If so, we learn that 47% of shark bites in French Polynesia occur during Shark feeds and that M04 bit a feeder in the hand. Both, we learn, prove that the risk of accidental bites has increased critically.
Well, gee, what a mind-boggling insight! Tremendous development of shark dives is leading to more bites!
I’ve blogged about it in extensohere and don’t need to repeat myself more than that: the precondition for a Shark bite is that a human and a Shark be in the same place at the same time (hellooooo…) and thus, feeding sharks does indeed increase the risk of getting bitten and more Shark feeds will indeed lead to more bites!
This is so trivial, it is painful!
By the same token, the act of commuting in aeroplanes increases the risk of fatal plane crashes - yes, believe it or not: it does!!!
So going back to square one: do we prohibit aviation as a consequence? No, we ask that anybody engaging in the activity, especially commercially, follow a regimen of strict safety protocols!
Right?
Now, it just so happen that I’ve done a multitude of Shark dives in French Polynesia.
Many of them were Shark feeds with mainly Greys and Silvertips - and yes, I’ve also witnessed several of the Moorea Lemon Shark feeds.
Any Shark bites?
Certainly: four of them, one by a Silvertip and three by Grey Reefs!
The cause: multi-user sites combined with Gallic panache and improvisation: poor Shark diving briefings leading to unpredictable behavior of the clients, ever changing procedures and feeders, creative chaos and heaps of bravado, zero protection of the feeders and clients alike – in brief, the recipe for certain disaster!
With that in mind, the described bite comes at no surprise whatsoever!
BUT!
Was that bite by M04 really aggression – and if so, due to what? Did the behavior of the feeder piss off the Shark? Did the Shark mistake him for a competitor? Is aggression really the most plausible explanation?
Here in Fiji, all of our clients have to wear dark gloves. The reason is that anybody without gloves will get nailed by the ever greedy Giant Trevally and Red Bass who mistake the pasty hands sticking out of dark wetsuits for bait. This is not aggression, this is a mistake!
Would it not be much more plausible to assume that M04 might have made the exact same mistake when in a hurry due to a competitive situation?
Bull Sharks are not Sicklefin Lemons and anybody who knows about Sharks knows that different Shark species have very different behavioral traits and that one cannot make generic statements across species - and certainly not make comparisons to, of all animals, Komodo Dragons!
Keeping in mind the above caveat, this is what we do in Fiji in order to increase the safety of everybody:
- This is a one operator site, meaning that we can enforce a uniform protocol that is always highly predictable – for the animals, not us!
- By the same token, the people feeding are always the same, to the point that they have developed personal relationships with individual Sharks
- Feeders wear chain mail gloves and clients, full body dark wetsuits and black gloves
- There is separation between the large Bull Sharks and the customers (remember the precondition above!)
- There are extensive dive briefings so that the clients know exactly how to behave and don’t startle the animals
- There is ample food and the animals are conditioned to follow a set routine, meaning that we are trying to minimize competitive pressure. We also always control the amount of food being introduced, meaning that when we sense any incipient tension, we can discontinue the feed and wait until everybody has calmed down again.
Could some of it be replicated in Moorea! Sure!
Long story short: the obvious solutionis not the annual cessation of the feeding activity for several months that implies the necessity to re-establish the feed, the relationships and the training of the animals - it is to improve the feeding protocols!
As to the other grievances about inbreeding and intra-specific aggression: not with our Bulls!
We’ve been keeping highly detailed tabs for 7 years now and none of the Bulls has taken up residency, let alone established a territory necessitating defense against conspecifics.
Instead, although the numbers continue to increase, we’re being faced with a continuous rotation of individuals who clearly lead a free life and are not dependent on Shark Reef for sustenance. Plus, they all vanish during the mating season which is a good indication for them doing plenty of walkabout and mixing of gene pools once they get horny!
The tally:
Bulls biting feeders: zero;
Bulls biting clients: zero;
Bulls biting Bulls: one documented case (we always have at least one camera rolling) where two homed in on a Tuna head and one very obviously missed the head and bit the other – yes, camera rolling! We have certainly never witnessed a single case of a Bull Shark resorting to biting in order to assert its dominance, and this in thousands of Shark dives – but then again, it’s a different species.
Fatalities among our 100 individually named animals, of a total of approx 300: only Jaws who has been missing since 2006.
All others are friendly, well fed and above all, locally protected - and I believe, perfectly happy!
Hence, what is the relevance of this paper to what we do and to Shark feeding in general?
You be the judge of that.
A day's catch in Hawaii. No effect on Shark behavior? Not a public hazard? And the Ecosystem?
You may have noticed that I've retracted a recent series of posts about the situation in Hawaii.
I did so after Patric from Shark Divers traveled to the islands and met with the two local Shark operators and the representative Gene Ward. Ward is spearheading a populist movement aimed at shutting down the Shark tours but on that meeting, he assured everybody that he was not anti-business but merely wanted to enforce the law that prohibits Shark feeding in state and federal waters.
The Shark operators have no problem with not feeding the Sharks. The Shark populations they visit on their tours three miles off the coast are resident Galapagos and Sandbar Sharks that aggregate there in response to the activities of crab fishermen. Whether anybody feeds them or not, that's where they now live - and not on the coast where all Shark attacks in Hawaii have occurred, incidentally NOT perpetrated by those species.
Since everybody involved in that private meeting seemed to agree on the way forward, I decided to facilitate the upcoming town hall meeting by desisting from any more "inflammatory" comments. I've watched a (painfully boring - the things one ends up doing for the "cause"...) video of the meeting and true to his word, Ward has kept most of his comments centered on the issue of legality. The law of course is bad and based on faulty assumptions - but I guess that's another fight for another day.
So far so good. What is not good are Ward's attack dog Makani Christensen and their Shark Task Force, a recent re-enactment of the venerable State of Hawaii Shark Task Force. Contrary to their predecessor that united community leaders, scientists, government officials and other stakeholders, this is a pure Shark hate group. They are aligned with safewatersforhawaii a local clone of the infamous anti-Industry CDNN (compare the "Myth vs Truth" section!) and stopsharkfeedinginhawaii and have literally thrown the kitchen sink at anything and anybody related to Shark viewing - from stoking fears that Shark viewing might lead to more Shark attacks, to "concerns" about the likely effects on the Sharks and the ecosystem (George Burgess - shame on you!), to claiming that it violates the sensitivity of native Hawaiians.
All of the above is of course rubbish (was that "inflammatory"?) and I shall be posting a series of excerpts from a document by a wise, and anonymous (which proves that he's wise!) Hawaiian debunking them in non-inflammatory lingo.
For the time being, read this. It's an eye witness account I received one week ago by "somebody" spearfishing on one of the Hawaiian islands.
XXX and I went snorkeling, and he was free-diving down to the bottom (~50 feet) to spear various fishes.
XXX is an incredible free-diver -- he casually drops down to 50 feet, stalks the fish for a while, then usually nails his target perfectly with a 3-prong spear. Anyway, on one dive down, he and I both saw a 4-foot white-tip shark swimming by, and neither of us gave it much concern. But then I saw a good-sized grey-reef shark come up from behind a rock where XXX couldn't see it. I was up at the surface, holding a mesh bag with all the bleeding/dying/thrashing fish . The shark circled around the rock and came up behind XXX, just inches above his right shoulder.
I saw XXX taking aim at a Uhu, and I yelled at him through my snorkel, "Don't shoot! Don't shoot!". He didn't see the shark right behind him, so when he heard me yelling, he thought I was saying "Uhu! Uhu!", like I was cheering him on. So he shot the Uhu and the shark went nuts (the white-tip had left -- only the grey-reef was still there). It bolted around in front of XXX where the thrashing uhu was at the end of XXXs spear. I thought for sure XXX would see the shark at that point, but apparently he somehow missed it, because he casually swung the spear around bringing the fish to his chest, so he could hold on to it while he swam back up to the surface.
The shark was thrashing around back where XXX had shot the Uhu, then started following up the blood trail right behind XXXs fins. As he was kicking upward, the tips of his fins were almost smacking the shark in the face. I kept yelling "XXX! XXX! Shark! Shark!", but he didn't seem to notice. Finally, when he was abould half-way up, he looked at me and I pointed vigorously behind him. He turned *just* in time to kick the shark off as it was charging him from behind. XXX kept kicking it off all the way to the surface, bringing himself, the speared Uhu, and the shark up to me.
I immediately held the mesh bag with the bloody fish out of the water above my head, and XXX tried to do the same with the Uhu; but the fish was too heavy and it bent his carbon-fiber spear over and the Uhu was flopping at the surface. This only amped up the shark even more and he charged XXX again, and XXX kicked it off. Then it charged me, and I had to kick it off (the blood was dripping down from the mesh back I was holding). XXX quickly got the Uhu off his spear and offered it up to the obviously hungry shark, but the shark didn't see it floating on the surface, and it kept charging us -- first XXX then me, then back to XXX, then back to me, etc.
At about this time, I noticed XXX was laughing in his snorkel. As soon as I noticed that, I suddenly realized that I had been (and still was) laughing in my snorkel also. I guess it's just a weird sort of reaction we both had -- and it was a funny scene, in retrospect. The shark turned away and headed for the Uhu, now a few feet away from XXX and I (as we were both back-peddling towards the boat).
But the shark somehow missed the Uhu, then turned back again for us. There was a big green cloud of blood below the Uhu, and the shark swam right through it. I expected the shark to turn and eat the dying Uhu, but instead it got even more excited and charged both XXX and I again. XXX kicked it off, then I kicked it off, and finally it found the Uhu, and took the entire thing into its mouth (except the tail), in one gulp.
XXX and I both saw it glide down back to the bottom, with the uhu tail sticking out of its mouth. I stopped laughing long enough to say "I think we might want to get back in the boat now"; and this only made XXX laugh harder. It was a very strange thing -- because it was both nerve-wracking and extremely funny at the same time.
After hopping back in the boat again for a few minutes, we both jumped back in the water and continued hunting for fish. We figured that the shark was now well-fed, and wouldn't bother us anymore. I did see it swim by later on, but it never came close. All the same, I left the mesh bag in the boat, rather than carry it around.
Aloha,
Interesting huh. Equally interesting that Ward's proposed legislative amendment to the Shark feeding ban includes the following exemption, and I cite.
c. Persons, including commercial and recreational fishermen, engaged in the taking of marine life that results in captured, injured, or dead fish being incidentally eaten by sharksshall not be considered in violation of this section...
Well well. So who, exactly, is feeding the Sharks close to shore and (for the sake of the -wrong- argument) "teaching them to associate humans with food"? Maybe spearfishermen like Ward's very own Makani? How many incidents like the one above happen inshore every day - and what do the Sharks learn in the process?
Ward may indeed not know this, but Mr. Christensen sure does: EVERYBODY from Florida to the Pacific to Oz knows that wherever there's regular spearfishing, the Sharks will start circling as soon as anybody enters the water and come charging in when they hear the sound of a speargun - to the point where some dive operators carry around speargun triggers to lure in Sharks!
Gene, it may be OK to try and enforce the law - although I'm sure that the state of Hawaii is facing more pressing problems right now. What is not OK is to be perceived as an anti-business, anti-tourism demagogue pandering to unfounded and irrational fear and being abused by fanatics who are pushing self serving agendas right from your very own office.
Vanessa Richardson contacted Andrew a while ago asking for his take on the Shark Diving Industry and whether we had changed anything after the Bahamas accident - the answer to that being, No why should we. The result of her interviews, Death of a Shark Diver, Redux is a free, public article and you can read it right here .
And you should. I must say that all-in-all, I like it. Not that I would agree with many of the opinions expressed therein - but still, it offers a largely unbiased overview of what is happening within the Industry, and that in itself is a good thing.
I particularly appreciated hearing something from Jimmy Abernethy. Me, too, I've never witnessed a Shark acting as if divers were potential prey and although I remain skeptical about his procedures, he really is a master of his trade and certainly among the best operators offering cageless macro Shark encounters in the Bahamas - especially after having witnessed the unspeakable mayhem and stupidity perpetrated by other operators and facilitators last year. Yes I know, "somebody" will object to my take, and there's still the open question of why Tiger Beach is not being protected - but that's what I believe and I stick to it.
Burgess being Burgess, I didn't expect much else from him. I certainly concur when he says that when Shark accidents happen, the culprits are not the animals but the people who attract them - hence the need for the strictest possible protocols if one decides to do so. Shark feeding is controversial and poorly researched and barring the publication of unequivocal data and results (keep watching this space!), everybody is entitled to an opinion - as long as it's not outright ludicrous and the person proffering it has some standing. Which of course leads me straight to the world's foremost shark expert, and only professional shark-human interaction specialist! Hilarious! This is really the one time where CDNN got it right - on Ritter and incidentally, on Discovery's bite shows as well! And I'll leave it at that!
I am a proponent of shark diving. While it does affect a few sharks, when compared to the approximately 100 million killed annually for fin and flesh the minimal impact of this human activity pales in comparison.
I feel that shark dives produce several very beneficial outcomes for humans and sharks. First exposing divers to sharks, safely and professionally - and in a beautiful environment will inevitably turn fear into fascination. Quickly these people become ambassadors for shark conservation. Further it produces jobs and income for areas and folks that need the work - especially in an economy such as the Bahamian one. Tourism in the Bahamas is the country's life blood, and sharks are a draw!!
As for hazard - tens of thousands of divers worldwide have safely enjoyed professional shark encounters ever since they were established in the Bahamas nearly 40 years ago. It is true that some people have been injured and there was even one fatality, but compared to other water sports this is a pittance.
Nearly a decade ago the World Health Organization estimated that over 400,000 people drowned in year 2000 making this the second leading cause of unintentional death after highway accidents. So shark dives turn out to be a very SAFE form of water activity when conducted in a professional way.
What I have written is controversial. Animal lovers think that humans have no right to interfere with non-human creatures. This is their opinion, not mine. Biologists always say "don't feed the animals." But I have been feeding sharks at my field station for over 20 years www.miami.edu/sharklab, and have observed their behavior carefully (my degree is inmarine animal behavior and sensory physiology).I know for a fact that our shark encounters do not greatly affect the Caribbean reef sharks we feed.
- They do not become habituated to humans such that they completely lose their natural fear. - They do not begin to consider us as food.
- They are very focused on what we do and learn almost instantly what the feeding situation means.
- They do not depend on us for food but hunt normally and supplement this ordinary behavior with our feedings.
- New individuals join the colony all the time, learn what we do and do not pose a danger. These reef sharks leave the area during breeding season in August and go about their normal reproductive activities. They return about three months later.
I cannot even begin to tell you how utterly rewarding (and surprising) it is to have a scientist of Doc's caliber make the above unequivocal statements. This is exactly our own perception and we're currently spending quite a bit of time collecting the data that will eventually lead to a paper dispelling the old tired "association" myth.
Thank you Doc, you're a shining beacon in an Ocean of ignorance and prejudice!
