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Stock Stewardship Discussion
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Stock Stewardship/Biomass Allocations
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If you would like to post a comment on this subject, please send your contributions to me (Dick Allen) at rba@FisheryConsulting.com for posting. I will post both positive and negative comments on the subject, but I reserve the right to prevent my web site from becoming cluttered with material that is not relevant to the discussion, or is otherwise unacceptable to me. I will publish any acceptable submission without editing. In any case where I consider the material to be generally worthwhile, but for some reason unacceptable, I will offer the contributor the opportunity to alter the objectionable content. If you don't want your contact information published, please do not include it in the body of your message.
I may open the page for direct submissions if I gain more confidence that it will not be vandalized or misused.
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Subject Trevor Response 2
Date
Tue Jan 25 2005 14:29
Author Trevor Kenchington
(tk@FisheryConservation.net)
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Dick,
I do not want to be drawn into a debate. That is your role, as a Council member, while mine is to provide technical advice. However, I should make a few responses for clarification.
You wrote:
> I still like the term stock stewardship shares
Very well.
The Council is already laboring under the confusions of "bycatch" to mean "discards" and "TAC" to mean "quota". Inventing yet another term for biomass allocations won't be anything new!
> Trevor expressed his belief that the Council workload might preclude consideration of biomass allocations at this time.
Not quite.
To re-state my recommendation: By my observations, NEFMC is struggling to apply time-tested management tools to meet the essential, year-to-year requirement to manage New England's fisheries. Once in a while, the Council over-exerts itself to apply something more innovative (though still not entirely novel) to a local situation (e.g. rotation management of scalloping -- though time will tell whether Amendment 10
was a sensible use of scarce Council resources). If that is so, then I doubt that NEFMC is an appropriate organization to take on the task of developing, from scratch, an entirely new management tool, which has been advanced as a theoretical concept perhaps 4 times but which has never actually been applied in the management of any fishery on the planet.
> Trevor also expressed concern that biomass allocation might enable one or more well-heeled share-holders to take over the fishery simply by not fishing for a few years. He suggests that the active participants could somehow be excluded from the fishery in this way. As I see it, that would not be possible. Anyone who did not fish on their allocation would be helping the active participants and would have no way to diminish the participation of the active fishermen.
>
> Consider a simple example. Assume that Benevolent Harvester (BH) and Capitalist Conserver (CC) each get an initial biomass allocation of 1,000 tons. CC decides to take over the fishery by not fishing on his stock. Let's say that his stock grows by 20% each year because he leaves its
surplus production to accumulate. That rate would slow as the stock grew, but that characteristic of natural populations does not affect our example.
> After 5 years, CC's stock reaches about 2,500 tons. BH keeps fishing at a sustainable rate, thus maintaining his stock at 1,000 tons. BH enjoys the high catch per unit effort that comes with stock abundance. His costs are therefore reduced and his profit is higher. The fact that his percentage share of the total stock has been reduced from 50% to 28% does not hurt him at all - he still has his 1,000-ton stock and he is making money off CC's conservation, not by catching more fish, but by catching them more easily. It doesn't hurt me if another customer of my bank lets the interest on his account accumulate while I take mine out every year.
>
> What is it that CC could do to exclude BH from the fishery? Why would CC even contemplate such a strategy?
Your theorizing follows exactly the same logic that John Caddy and the rest used when advancing the various versions of biomass allocation (except mine, which dodged the issue by exploiting the particular dynamics of redfish). However, as I stated in my previous message, once I used a quantitative model to investigate what would really happen, the
argument that you advance proved to be false.
To figure out why and to see whether there are any exceptions, I would have to either dig out long-archived files or else spend a few days on re-running the model. I don't intend to do either at this point. (Though, if anyone wants to take this idea seriously, some model-based
explorations would be a good next step. If anyone wants to play around a bit, I dare say that my model could be made available, though it would need clearance from FAO. For serious work, I would recommend getting a skilled modeller to come up with something more sophisticated than an Excel spreadsheet model.)
However, although I can't remember what I figured out a decade ago, I'll take a guess at why the model produced the results that it did:
In your example, BH and CC are each allocated 1,000 tons of biomass. Since it is a U.S. fishery, OM (Omniscient Manager) sets a maximum harvest rate for each participant at the 20% sustainable level. (Let us also suppose that this fishery's resource is conveniently free of all effects of variable environments.)
BH, minding his own business and only wanting to fish in a responsible, sustainable way, sets out to harvest 200 tons per year, confident that OM's calculations are correct and that he will thereby retain his 1,000 ton biomass allocation and his on-going ability to harvest 200 tons annually.
CC doesn't figure that it is worth gearing up for just 200 tons, so he stays out of the fishery. But, since OM has conferred on him a biomass allocation, he does expect to reap the benefits of his conservation at some later time.
After 5 years, the 1,000 tons that CC has not harvested add to the initial 2,000 ton biomass and the total resource biomass is 3,000 tons,less some amount lost to the various non-linearities in the system. Your 2,500 tons is probably a bit low but let's go with that figure.
The trouble is in that missing 500 tons. As biomass builds up,
density-dependent effects don't only slow the increase in CC's portion of the resource. They also cut into the production of BH's share.
[Actually, in most marine fishery resources, it density dependence isn't the main issue. Because CC isn't fishing, the total mortality rate is lower than expected by OM, the average age of the animals is therefore higher and older fish grow more slowly. But no matter: The consequences
for BH are much the same.] So BH's 1,000 tons no longer produce an annual surplus of 20%. BH can continue to harvest 200 tons per year but,if he does, he will see his biomass allocation dwindle. Or he can retain the 1,000 tons by cutting his own fishing -- staying sustainable but by
sustaining a higher biomass in the water than OM has found to be optimal.
If that is the mechanism (and I am theorizing here, not presenting an analysis of my model's performance), the results are a bit more subtle than my previous report of my memory from years ago. BH isn't doomed to lose his fishery to CC. But he cannot operate independently of the consequences of CC's choices (which was what John Caddy promised that
biomass allocations would do). If CC chooses not to fish, BH has the choice of (1) continuing to take his share of the optimum yield and seeing his biomass allocation wither away, (2) trimming his annual catches so as to maintain his biomass allocation in the face of CC's excessive conservation, (3) shutting down and maintaining his percentage share of the biomass as the resource rebuilds towards virgin levels, or
(4) some intermediate strategy.
I suggested in my last that these problems could be overcome if enough thought was put into development of the idea. One option might be to guarantee that the biomass allocation of anyone who harvested within 10% of the official OY would have next year's allocation based only on this year's, the standard schedules for growth and mortality, plus whatever
recruitment the ocean provided. Anyone who stayed out of the fishery or took no more than a token amount could be given a new allocation based on an assumption that they had taken their share of OY. People who took catches between those limits could find the fruits of their conservation being reduced, pro rata, so as to fit them all within whatever biomass then remained (though there might be excess amounts to share among all players by some formula).
That sort of thing could be done but it would clearly be complicated and messy (in its application as well as its design), which isn't what biomass allocation systems are supposed to be.
Once again: I do not doubt that biomass allocations could be developed into an effective tool for some fisheries. I do question whether figuring out how to do that is a sensible use of NEFMC's limited resources. Still, I only pose that question. Answering it is for the Council and its Executive Committee.
> Trevor also asserts that "the optimum yield is, by definition, the catch obtained by fishing at a rate that maximizes net benefits to the nation," and that a
shareholder who chose to underfish would be reducing the net benefit to the nation. I'm certain that Trevor is misusing the concept of optimum yield, and how it might be calculated
Then I suggest that you re-read the relevant sections of
Magnuson-Stevens and the National Standards Guidelines. While my words were not a direct quote, I think you will find that the ones you quoted above capture the legal meaning of OY. The consequences of underfishing, under a biomass-allocation system, then follow directly.
The situation under current management is, of course, different since present DAS allocations are set assuming that not every permitted vessel will participate in the fishery and not all those which do will use all allocated DAS. (At least, scallop management works that way. I assume groundfish management does also.) In that setting, failing to use your
allocation only reduces net benefits to the nation if so many people do it that OY is not harvested.
There is a quite separate issue of how much underfishing is needed before the cut in net benefits to the nation is enough to worry about. I am only pointing out the qualitative direction of the effect, not its quantitative magnitude.
Trevor Kenchington
--
Trevor J. Kenchington PhD
Gadus Associates,
R.R.#1, Musquodoboit Harbour,
Nova Scotia B0J 2L0, CANADA
Science Serving the Fisheries
http://home.istar.ca/~gadus
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