Tuesday, August 13, 2013

Shark Tourism Valuations - straight from the frothy Piranha Tank!


Love it!
This is how real science happens - by means of toothy debates!

Remember the Catlin paper?
Obviously Gabe was less than amused by the negative references to his Palau paper - the more since what was being criticized is not even in the paper proper! I'm not gonna ask you to fork out an extortionate 32 bucks for a mere letter, so here's what he states.
Valuing individual animals through tourism: Science or speculation? – Reply to Catlin et al. (2013)

In their recent article, Catlin et al. (2013) point out that there are challenges in placing an economic value on individual wild animals based on benefits to the tourism industry, and argue that it should not be done. 
While they are right to highlight the difficulties, the authors have failed to clarify the relevant economic questions or identify the appropriate economic theory. For certain economic questions, individual valuations are legitimate and, given sufficient data of an adequate quality, can be estimated rigorously. As a result, their conclusion that, ‘‘The fundamental characteristics of wildlife tourism activities do not lend themselves to valuation at the individual animal level’’ is incorrect. 

Catlin et al. fail to make the crucial distinction between average valuations and marginal valuations. 
The marginal value (for tourism) of a single individual wild animal is the answer to the question, if one animal was removed, by how much would the net revenues of the tourism industry fall? The average value is the answer to a question such as, if the whole population of animals of concern was removed, by how much would the net revenues of the tourism industry fall per animal removed? Assuming that both questions could be answered, the answers are likely to be very different. 

In reality, as Catlin et al. point out, the effects of removing an individual animal on the whole population and on the tourism experience would be extremely difficult to anticipate and quantify.
However, this is not of great concern because (unusually for economics) the marginal value is not relevant to the key policy questions. Questions such as ‘‘should a shark sanctuary be created?’’ are not about marginal changes in the shark population, but about large changes – potentially from none or almost none to a large population. In such cases, it is theoretically sound to compare the average value of sharks for tourism with the average value of sharks for fishing. Indeed, the comparison is simply a scaled down version of comparing the value of a whole shark population for tourism with its value for fishing. 

Catlin et al. criticise Vianna et al. (2012), stating that we calculated an annual (US$179,000) and lifetime (US$1.9 million) value for individual reef sharks’’. 
No such data were presented in Vianna et al. (2012). Given this error by Catlin et al. it is ironic that they criticise the ‘‘. . .tendency for these figures [individual valuations] to be referenced without much care’’. However, we did include these individual values in an unpublished report on the shark ecotourism industry in Palau (Vianna et al., 2010). Our estimates were possible because of a definitive understanding of the number of sharks present in the population and their interactions with the tourism industry. Data were obtained through a comprehensive tagging and community monitoring program that returned more than 2 million detections of tagged animals and >3000 sighting logs over seven years at all the major dive sites in Palau. We chose not to present any individual valuations in Vianna et al. (2012) primarily in order to avoid the need for a detailed explanation of the difference between marginal and average values. Instead we provided results at the population level, which would have been functionally identical to results based on average values. 

Commenting on our conclusion that sharks in Palau are worth much more alive than dead, Catlin et al. state that ‘‘whilst this may be true, such a conclusion cannot be drawn for the reasons outlined above’’. 
We refute this statement on the grounds that our analysis uses a theoretically sound economic framework, is based on high quality data (including precise knowledge of the number of animals that underpin the tourism industry), and does not violate any of the other concerns raised. We found that the value for tourism of a population of live sharks was five orders of magnitude larger than their value for fishing. Even allowing for uncertainties in our study, no plausible scenario could reduce the tourism value to make it remotely similar to the fishing value. 

Catlin et al. also insinuate that, because our study was financially supported to a small extent by an NGO, our results may have been influenced to meet the advocacy agenda of the funder. We refute this offensive suggestion. We note that of 51 recent articles with funding disclosures in BC (volumes 153 and 155), nearly a third were supported by NGO contributions. 

Although we agree with Catlin et al. that calculations of individual value can be problematic, and we do not vouch for the quality of the other studies cited, nor for the usage that others may make of our results, it is clear that average individual values can be estimated soundly.
To which Catlin replies as follows.
And yes you've just spared yourselves another 32 bucks - adopt a Fiji Bull Shark instead!
Keeping perspective on using tourism values for conservation – Reply to Vianna

In response to Valuing individual animals through tourism: Science or speculation? – Reply to Catlin et al. (2013).
 We welcome this further discussion of studies that use wildlife tourism revenue to determine the economic value of individual animals. No single study critiqued in our article (Catlin et al., 2013) makes every mistake that we noted nor does any one study overcome all the problems that we identified. While Vianna et al. make some interesting and useful points in response to our paper, we still contend that, in order to ensure that the ascribing of tourism valuations has a positive influence on conservation goals, valuation at an industry, location, or other higher scale is a more robust and reliablemeasure than is the valuing of individual animals.

For instance, in Palau the sharks that interact with the tourism industry would only make up a very small portion of the country’s shark population. Therefore we argue in our paper that comparisons such as the one put forth below are potentially irrelevant and misleading.
If these fishers were engaged in shark-fishing activities, the maximum revenues that they could obtain for the once-off capture and sale of the sharks interacting with the tourism industry would be around US$196, or only 16% of the annual income each one would have earned by keeping these sharks alive. (Vianna et al. 2012 p. 275) 
Despite this, Vianna et al. continue to suggest, in response to our article, that ‘‘it is theoretically sound to compare the average value of sharks for tourism with the average value of sharks for fishing’’.

Vianna et al. do make an important point – one which we acknowledge was not well explained in our paper, or indeed in any other paper on the issue of individual valuation of wildlife. Studies of individual value based on tourism revenue measure average value rather than marginal value. Average tourism value is the total estimated (usually) or measured (more rarely) tourism revenue averaged across the population, while marginal value is the additional value that one more animal might bring, or that would be lost if one animal were to be removed.

While valuation studies based on tourism measure average value, market prices for extractive uses of wildlife, such as fishing, are marginal. Our article is trying to point out that the two values are often confused. Many articles, including Vianna et al. (2012), compare these values without explaining that they are not directly comparable.

In their response to our paper, Vianna et al. claim:
. . .this is not of great concern because (unusually for economics) the marginal value is not relevant to the key policy questions. Questions such as ‘‘should a shark sanctuary be created?’’ are not about marginal changes in the shark population, but about large changes – potentially from none or almost none to a large population. 
We suggest that policy situations where such a black and white decision about an individual or a small number of animals is being made are actually rare. More subtle policy questions relating to issues such as hunting offtakes, allowable fishing catch, or whaling in international waters are far more common. In many policy situations consumptive and nonconsumptive uses of animals are not mutually exclusive. In such situations confusing the use of average values with marginal values could easily mislead and thereby produce poor conservation and policy outcomes.

We categorically do not suggest that researchers are producing these individual animal valuations corruptly, at the behest of sponsoring organisations. Our concern is that these results are generally obtained at least imprecisely if not unscientifically and can then be easily misinterpreted. We feel that Vianna et al. have not properly comprehended our criticisms of the poor data obtained and the even worse assumptions and extrapolations made in the majority of studies and articles that have attempted to value individual animals for tourism purposes.

We therefore reiterate our original contention ‘‘The fundamental characteristics of wildlife tourism activities do not lend themselves to valuation at the individual animal level.’’
Wonderful stuff! :)
IMO, both are correct - Catlin in principle but Gabe in the specific context of his Palau valuation paper.

Because in Palau, the tourism Sharks are essentially Grey Reefies.
From what I've observed, this species forms natural aggregations with high (but not absolute!) site fidelity that are comprised of subadults and adult females, whereas the adult males are believed to roam further and deeper and all the way into the open ocean, and to thus provide for gene flow. 
Thus, those aggregations could be considered to be semi-closed populations where the removal of individuals would not easily lead to replenishment from outside - the more as any foreign females would be residing in their own aggregation sites! As a consequence, the valuations for those Sharks are likely to be highly accurate - especially considering the staggering amount of data that have been collected! By the same token, if the Sharks in e.g. Blue Corner were to be fished out, this would have a devastating effect that would likely linger for a very long time and severely impact tourism revenues.
This is in stark contrast to, say, our Bulls that are known to roam over very large ranges, with site fidelity hovering around 50% see e.g. here. Over time, it is quite possible that most Bulls in Fiji will have discovered the SRMR, meaning that whilst we're showcasing up to 100 per day, the possible total number of visiting Sharks could once reside in the thousands!
Or take e.g. Cocos and the Galapagos where the Hammers are highly migratory and where the rampant fishing and poaching has dramatically reduced numbers but not (yet?) led to the collapse of Shark tourism.
There, assigning valuations to individual Sharks would be highly misleading!

But the take-away message I believe remains the same.
Those individual valuations are fluff that will generally not stand up to scrutiny.
What however is totally valid are nation- and sector-wide valuations, and this especially when based on original research like the Fiji Shark Tourism Valuation as opposed to meta-analysis, uncritical citations and outright hearsay like some other publications  - like especially this one!!!

What is equally valid is to state that a live Shark is more valuable than a dead one - especially if considering its ecosystem services, something that somebody really ought to finally analyze!
Ambitious but not impossible!

So be careful when using those numbers.
They sound great - but in essence, they are not true and as such, bad conservation.

2 comments:

Johann Mourier said...

I also think it is context dependant. Individual animals can give back some interesting information as Gabe mentioned. In our paper Clua et al. (2011), we showed for example that individual lemon sharks do not contribute similarly to the local economy when you consider the residency of each individual compared to a contribution average over the total population size... I think both individual based and regional based measures are important because they provide complementary information. Individual based measures are valuable for small population sizes such as in most of insular location.

DaShark said...

Yes of course it's circumstances-dependent Johann - that is, provided that the valuations are based on solid data!

Unfortunately, most of those valuations are not - and then you end up with stuff like Cisneros-Montemayor that is being paraded all across the media in "support" of Shark conservation!

Have you read it?
Absolutely shocking, to the point of being outright embarrassing!