From: steinn@sandy.ast.cam.ac.uk (Steinn Sigurdsson)
Newsgroups: sci.environment,talk.environment
Subject: Re: Seals and fish
Date: 6 Sep 95 13:29:53
Organization: IoA, Cambridge
Lines: 269

In article <42fonv$ep9@inforamp.net> sbest@inforamp.net (Stephen Best) writes:

   steinn@sandy.ast.cam.ac.uk (Steinn Sigurdsson) wrote:

   >So who gets the null hypothesis? You have quasi-religious reasons
   >for not wanting marine mammals killed, no matter what. Hardly an
   >unbiased observer. The fishermen have historical tradition on their
   >side, why should they not kill the seal?

   Firstly you have no knowledge that I'm aware of about what my personal
   beliefs are on this matter.  And secondly, the subject of this thread,

We have debated this and related topics on the Net in the past.
You made some statements then regarding your belief in whether
marine mammals can ever be hunted. I took you at your word
and remembered.

   one that my critics it seems are having a great deal of difficulty
   adhering to, is whether or not the premise that "less seals = more
   cod" can be supported scientifically.  Are you not able to understand
   the topic or do you simply lack a worthy opinion on it?

Tsk. Temper, temper.
You are requiring a level of "scientific support" that is
impossible to ever attain, and you know it. You are also
doing so deliberately in order to force the debate to
your predetermined conclusion. Insulting people who might
disagree with you will not help your argument any further.

As I noted before, the level of scientific certainty you
demand is such that no action taken in regards to fisheries
management can be supported scientifically - so presumably all
controls should be lifted and the fisherman permitted to do what
they wish?

In real life decisions have to be made on incomplete or
less than rigorous data and conjectures. It is always possible
to modify ones behavious as new information becomes available.
Lack of certainty is not a prescription for paralysis.

   >You ignore that the fact that there is also data which does
   >not qualify as scientific - in that it was not collected systematically,
   >with the proper controls or baseline comparisons. Yet most people
   >who actually do fishing seem to be under the impression that holding
   >down the number of seals will help fish stocks recover more rapidly
   > - think of it as native knowledge...

   I do not ignore either the presence or the value of anecdotal
   knowledge and experience; I simply didn't mention it.  Nevertheless,

 ??? You have some definition of "ignore" I'm not familiar with?

   that is not the premise on which the "less seals = more cod" equation
   is being presented.  It is being presented as science, which it most
   emphatically is not.

No, it is being presented as policy and rationalised as science,
with all but the press and some of the sillier "environmental"
groups acknowledging that we live in an uncertain world and must
do the best we can with limited information.

   >There is also fair amount of anecdotal evidence that this is in fact
   >the case, notably by comparing fisheries where the local seal population
   >was controlled by culling versus locales where seals were allowed to
   >expand freely.

   To the best of my knowledge there is no scientific evidence to support
   this statement.  Dr. Orenstein in a previous posting has suggested
   that there are scientific studies, not anecdotes, which seem to show
   otherwise.

Your knowledge doesn't seem to be all that good.
There is also the slight problem that studies showing that
suppression of seal population in other particular instances
are not certain predictors of what would happen now in Canada,
they are at best indicative in the absence of a correct theory
of population response.

   >BTW eating of cod (and other commercial fish) is not the only
   >reason seals are culled. They also carry parasites that prey on
   >commercial fish.

   This statement is also used by proponents of sealing, suggesting that
   a reduction of seal populations will result in reduced parasite loads
   in commercial fish species.  There is, again, no scientific basis for
   this statement.  It is not possible to predict that a reduction in
   seal populations would have this effect.  The statement is propaganda
   and not science.

Oh crap. The seals and cods to have common parasites and they
do transmit from seals to cod. Notably ring worm. Are you honestly,
with a straight face, going to claim that curtailing a carrier of
a parasitic infection does not generally as a first order effect
reduce the probability of transmission? It is conceivable that
some subtlety of the infection cycle could lead to higher
infection among cod if the seal population is decreased but
the burden of proof in that case is to show that is the case.

   >No, you are being silly. It is based in part on desperation. Seal culling
   >_may_ help the commercial fisheries recover, in which case many people
   >figure it is worth a try, the seals are not endangered. I don't think
   >anyone actually believes your conjecture that an increasing seal population
   >would help the cod stocks recover. It makes an amusing rhetorical
   >device for reduction ad absurdum counter arguments - but do you
   >even actually believe that is the case?

   You are putting arguments in my mouth which I did not make.  What I'm
   saying is that there is no scientific basis to suggest that "less
   seals = more cod."  If you believe that "desperation" is the basis of

Well, if there are less seals, there will either be more, same or
less cod. If you are arguing that there will not be less, then either
you propose there will be the same - that the seals are irrelevant
to the cod population, or that there will be more. There is no
other possibility. This is a reasonably inference to make from
your statement.

   reasonable fisheries management policies that simply defines your
   approach to these issues, but it is not science. And science is what
   the Canadian Department of Fisheries and Oceans purports to base its
   management policies on.

The Canadian Department of Fisheries is desperate, that is not my
approach, but my opinion. They fucked up big time with lots
of help from local politicians and fishermen. They do try to
base their policy decisions upon science, weighing the uncertainties
involved. When you are desperate you try options that are plausible
but not certain. As it happens culling the seals is one of the
three plausibly effective actions they can take to help the cod recover.
They've already come down on the EU, which was the most effective
plausible action.

   >Well, yes there is. One of the seal prey populations is depressed
   >and stabilising the seal population may help that prey recover.

   Again, if I understand your point correctly, whether the prey is cod
   or another species, the same fact applies: there is no scientific
   evidence for what you are suggesting.  Populations of marine predators

Yes there is. In general if a prey population is depressed relieving
predation pressure helps it recover. That is why the Canadians stopped
fishing, and since the seal take is comparable to the human take it
is plausible, scientifically, that trying to limit the seal take will
also help the cod recover.

   and prey fluctuate naturally in relationship to each other and as a
   consequence of unforseeable natural events.  Furthermore, it is
   utterly beyond scientists or fisheries managers to say how much a seal
   or any other marine predator population would need to be reduced to
   achieve the goal you are suggesting vis a vis the prey species.  It is
   utterly beyond our competence.

Speak for yourself.
We do not have enough data or theory now for certainties,
so we live the uncertainties and act in ways we think are plausibly
optimal. As we go along we get more data and change our behaviour if
deemed necessary or desirable.

   >But, by your own argument we don't even know that stopping the fishing
   >will help the cod recover - it seems that no management is scientifically
   >based, so presumably there should be no management at all?

   This is true, we don't know if stopping all fishing will result in the
   recovery of cod stocks.  What is true is that, unlike the situation
   with domesticated plants and animals, our knowledge of wild species
   and wild ecosystems is so poor that they basically defy management as
   the term is generally meant.  It is not too difficult to maintain a
   sustainable population of herefords, carrots, or corn, but cod,
   salmon, or redwoods are another matter altogether.

No they're not. We simply do not have as much data or as strong
a capability for intervention. Yet. There is no problem in principle.

   >Actually, I also would like to see a reference to why you think
   >Maximum Sustainable Yield hypothesis is wrong.

   It's obviously wrong, it doesn't work.  Look at the world's fisheries.
   The best reference I can think of is the father of the MSY theory, Dr.
   Sidney Holt.  He and Ray Beverton developed the theory and today Holt,
   a member of the International Whaling Commission Scientific Committee,
   is the most vocal critic of the theory.  If you wish to discuss the
   matter with Dr. Holt, the IWC will likely provide a contact address.

I have his address. Why do _you_ think MSY is wrong?
The world's fisheries decline have a more proximate cause
then MSY being wrong or even mis-applied. Notably lot of people
cheat, badly. Also there is the lack of jurisdiction over
extra-territorial waters, like the edge of the Banks, and the
Atlantic loopholes - stocks are overexploited as they move through
these loopholes, one of the most urgent activities in fisheries
management right now is close these loopholes.

   >The concept is based on an over simplified
   >theory, but it is also quite robust. If you allow for stochasticity
   >and multi-level predation the optimum population level and take
   >may be somewhat different (and more seriously, time varying)
   >but that is lesser issue. Of course MSY neglects future discounting,
   >but that is proper in my view - if you allow for that the MSY becomes
   >very different.

   Re-read your statment.  Do you seriously purport to offer this as a
   defense of MSY?  It's an indicment.  The complexity of the modeling of
   a dynamic ecosystem that you are suggesting is utterly beyond our
   present scientific abilities, and probably always will be.  It is not
   possible to "allow for stochasticity and multi-level predation" when
   we are unable to determine not only what all the predators are, but
   also how they interact.  We can't even predict how three simple
   orbiting bodies interact when the only force influencing them is there
   own gravitational fields, let alone the interaction between thousands
   of species from single-celled to social mammals.  You may wish to
   start another thread on sci.environment about MSY, as that is not the
   topic under discussion here.

You raised the topic, not me.
You are also completely and utterly wrong about
what can and cannot do about modeling. The intractability
of the three body problem is not particularly relevant
(for your information the three body problem is not only
soluble to arbitrary precision, there is an exact series
solution to it - the solution is intractable, not impossible.
Further, while uncertainties in the input data may preclude
accurate long term prediction of the evolution of some three body
systems, it is easy to do short-medium term solutions, and the
resolve as new orbital parameters are observed. Further than that,
the ensemble averaged behaviour of a set of interacting three bodies
is easily described with fairly simple approximations).

It is possible to allow for stochasticity and multi-level predation,
current generations of population models do just that. More data is
needed to learn what the interactions are in actuality, and to validate
current models and approximations. Further, while details of a
particular prey/predator relation may be wrong, the mean behaviour of
the populations may be well described. As most critics of develping
sciences and its applications you implicitly assume the field is
static and incapable of learning, in practise people respond to new
data and correct their modeling. That is the whole point of the
enterprise.


   To reiterate, the subject of this thread is the scientific validity of
   the statement "less seals = more cod."  There is no doubt that many
   people believe this statement to be true.  But that does not prove
   it's true.

The fact that the statement is not proven true does not mean it isn't.

	Many people believe smoking cigarettes does not contribute
   to disease, believe Elvis is alive, and believe aliens mutilate
   cattle.  But again there is no scientific evidence to support the
   statment "less seals = more cod", despite often desperate attempts on
   the part of scientists employed by fisheries departments to produce
   such evidence.

   Now if you believe that managing wild species and wild ecosystems on
   the basis of local economic need, unsupported beliefs, anecdotal
   knowledge, the perceptions of the exploiters of wild resources, and
   lack of knowledge is appropriate then you should be quite content with
   the present situation.  It is unfortunate, however, that this approach
   has resulted in such massive declines in most of the world's
   fisheries.

Management of resources has to be done on the basis of the best
data and hypothesis available. Your personal prejudices are mostly
irrelevant to the problem of feeding people.

From: steinn@sandy.ast.cam.ac.uk (Steinn Sigurdsson)
Newsgroups: sci.environment,talk.environment
Subject: Re: Seals and fish
Date: 6 Sep 95 13:37:20
Organization: IoA, Cambridge
Lines: 28

In article <42i94h$2no@inforamp.net> sbest@inforamp.net (Stephen Best) writes:


   If any evidence is needed as to just how wrong a group of scientists
   can be, simply look at the work Norwegian scientists have done in
   regard to minke whales.  Work which the International Whaling
   Commission has utterly discredited but which was hotly defended by
   those, many on this newsgroup, who failed to look closely at the

The error as I recall was a numerical error causing an approximately
20% change in the stock estimates. As the quota the Norwegians picked
had a large "safety" margin, this would not have actually lead the
stock being endangered. As it was the Norwegians chose to keep the
same margin and reduce the quota.
The main debate on the newsgroup was over a contention about
an assumption made in the stock surveys. Essentially there is
a "completeness" correction made in counts - assuming that not
all whales in an area surveyed are seen. The norwegians assumed
some fraction was seen, some people, notably an english scientist
whose name I forget, claimed a larger fraction of whales was observed
than assumed and hence the stock overestimates. This was something
testable by combining aerial and surface surveying, and the assumption
was in due course tested.

From: steinn@sandy.ast.cam.ac.uk (Steinn Sigurdsson)
Newsgroups: sci.environment,talk.environment
Subject: Re: Seals and fish
Date: 7 Sep 95 08:25:41
Organization: IoA, Cambridge
Lines: 63

In article <42fonv$ep9@inforamp.net> sbest@inforamp.net (Stephen Best) writes:

   steinn@sandy.ast.cam.ac.uk (Steinn Sigurdsson) wrote:

   >BTW eating of cod (and other commercial fish) is not the only
   >reason seals are culled. They also carry parasites that prey on
   >commercial fish.

   This statement is also used by proponents of sealing, suggesting that
   a reduction of seal populations will result in reduced parasite loads
   in commercial fish species.  There is, again, no scientific basis for
   this statement.  It is not possible to predict that a reduction in
   seal populations would have this effect.  The statement is propaganda
   and not science.


It took me about 5 minutes to find the below citation.
You really do not look very hard to find evidence that
contradicts your prejudices.

Read the last sentence carefully.

     CORYNOSOMA-WEGENERI (ACANTHOCEPHALA, POLYMORPHIDA) AND PSEUDOTERRANOVA
     DECIPIENS (NEMATODA, ASCARIDOIDEA) LARVAE IN SCOTIAN SHELF GROUNDFISH
     Article (Refs:30)
     by Marcogliese-DJ (*R) Mcclelland-G
        Maurice Lamontagne Inst,Fisheries & Oceans Canada,Pob 1000/Mt Joli G5H
        3Z4/Quebec/CANADA/

     CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES
        v49 (10) : pp2062-2069 (1992 Oct)


       We examined larvae of the seal parasites Corynosoma wegeneri and
    Pseudoterranova decipiens in various fish species collected from Western
    and Sable Island banks between February 1989 and October 1990. Atlantic cod
    (Gadus morhua), haddock (Melanogrammus aeglefinus), American plaice
    (Hippoglossoides platessoides), yellowtail flounder (Pleuronectes
    ferrugineus), windowpane (Scophthalmus aquosus), longhorn sculpin
    (Myoxocephalus octodecemspinosus), and sea raven (Hemitripterus americanus)
    were infected by both parasites, longhorn sculpin being a new host record
    for C. wegeneri. Only C. wegeneri occurred in winter flounder (Pleuronectes
    americanus), and neither parasite was found in northern sand lance
    (Ammodytes dubius) or capelin (Mallotus villosus). The two parasites were
    most numerous in sea raven and longhorn sculpin. Corynosoma wegeneri was
    more prevalent in fish sampled in 1989-90 than in previous surveys of
    Atlantic cod and haddock from the Scotian Shelf. Pseudoterranova decipiens
    and C. wegeneri occurred throughout the sampling area, but small fishes in
    the vicinity of Sable Island had the heaviest sealworm infections, and both
    parasites in longhorn sculpin declined with distance from Sable Island.
    Increases of C. wegeneri in groundfish, like recent increased levels of P.
    decipiens infection on the Scotian Shelf, can be attributed to the dramatic
    growth of the grey seal (Halichoerus grypus) population on Sable Island.

From: sbest@inforamp.net (Stephen Best)
Newsgroups: sci.environment,talk.environment
Subject: Re: Seals and fish
Date: Fri, 15 Sep 1995 12:55:07 GMT
Organization: International Wildlife Coalition
Lines: 31
Message-ID: <43bssc$802@inforamp.net>
Reply-To: sbest@inforamp.net
NNTP-Posting-Host: ts8-02.inforamp.net
X-Newsreader: Forte Agent .99b.112

Simen.Gaure@math.uio.no (Simen Gaure) wrote:

>Certainly, if Mr. Best
>is a scientist he can not absolve himself from
>this misuse of science.
>

I deeply resent this slur on my character.  I most certainly am not a
scientist.  I am a lying, hypocritical, corrupted, demonizing, fund
raising, win-at-any-cost, extremist, self-styled animal rights
environmentalist, and proud of it.  I achieved this status entirely on
my own initiative.  And I will not have over 20 years of hard work and
witnessing countless horrific things inflicted on wildlife and
ecosystems reduced to the level of a "scientist."

I deserve a grovelling apology from yourself, sir.  And I will have
satisfaction.

Yours with odious contempt!




--
Stephen Best, Vice President, International Wildlife Coalition
PO Box 988             |  Tel 519.925.3440  Fax 519.925.2003
Shelburne ON Canada    |  e-mail: sbest@inforamp.net
L0N 1S0                |  http://www.webcom.com/~iwcwww/

From: Simen.Gaure@math.uio.no (Simen Gaure)
Newsgroups: sci.environment,talk.environment
Subject: Re: Seals and fish
Date: Fri, 15 Sep 1995 15:59:55 +0200
Organization: University of Oslo
Lines: 118

In article <43bssc$802@inforamp.net>, sbest@inforamp.net wrote:

  Simen.Gaure@math.uio.no (Simen Gaure) wrote:

  >Certainly, if Mr. Best
  >is a scientist he can not absolve himself from
  >this misuse of science.
  >

  I deeply resent this slur on my character.  I most certainly am not a
  scientist.  I am a lying, hypocritical, corrupted, demonizing, fund
  raising, win-at-any-cost, extremist, self-styled animal rights
  environmentalist, and proud of it.  I achieved this status entirely on
  my own initiative.  And I will not have over 20 years of hard work and
  witnessing countless horrific things inflicted on wildlife and
  ecosystems reduced to the level of a "scientist."

  I deserve a grovelling apology from yourself, sir.  And I will have
  satisfaction.

What about posting Mr. Stenson's commentary?  That's what
I talked about in the context you removed.
You posted the criticism ("Sealing their doom")
of his report; you ought to post his commentary. I've sent it to you.
I'll do it for you with Mr. Stenson's permission.
And apologies to Mr. Stenson for having misspelled his name
in this thread.

<BEGIN QUOTE>
Date: Mon, 4 Sep 1995 22:11:05 -0230
To: Multiple recipients of list MARMAM <MARMAM@UVVM.BITNET>

In a recent posting, AnmlPeople@caol.com submitted a reprint from their
magazine call 'Sealing their Doom'. Unfortunately, the author of this article
misunderstood or incorrectly quoted a number of aspects of the 'Report on the
Status of Harp Seals in the Northwest Atlantic' which I prepared. This report
is a brief summary of a number of documents which are referenced in the
report. If the author(s) wish to understand the work which has taken place,
perhaps reading the original studies would help. In the meantime, however, I
will try to correct some of the specific points raised.

The article states that the quota was 175,000 between 1972-1982 and that it
was raised to 186,000 after the offshore hunt ended in 1983. The first quotas
were set in 1971 at 245,00 and flucuated between a minumum of 126,000 in 1976
and 186,000 in the early 1980's.  The 175,00 was near the average quota for
the time period and the quota has remained at 186,000 since 1982 (before the
offshore hunt ended). Since 1983, catches have flucuated from 19,000 in 1985
to 94,000 in 1988. In the last five years, the commercial catches continued
to flucuate but the average is similar the 1983-1990 average (~50,000).

The author is not clear how a decline in the estimated reproductive rates in
the late 1980's resulted in an increased total population. Harp seal
populations are estimated from a model which incorporates estimates of the
number of pups born (determined by aerial surveys or mark-recapture
experiments), reproductive rates of females, and catch statistics. A decline
in female reproductive rates raises the total population estimate since it
requires more females to produce a given number of pups (which is estimated
independently). The author also quotes the report as saying that the
population is growing at 1% and therefore should be lower than the 1994
estimate of 4.8 million. In fact, the report states that the population is
growing at approximately 5% (not 1%).  The rate at which the population is
growing has changed over time; the 5% is from a comparision of the 1993 and
1994 estimates of total population. The article also states that "assuming
Stenson's estimate ....in 1990 is accurate despite the likelihood that it
isn't". If there are some data which indicates that this estimate is not
accurate I would appreciate learning about it. A dislike of the result,
however, is not a reason for rejecting the estimate.

The article continues to state that "using Stenson's own population figures"
per capita consumption has declined fropm 2 - 2.4 tonnes of fish in 1981 to
1.4 tonnes in 1994. I am not sure which figures the author is refering to.
The amount of prey (fish and invertebrates) consummed by a individual was
estimated from energy requirements based on body weight and the costs of
activity and growth. Total consumption estimated by mulitplying up by
population size later. Therefore the amount of prey consummed by a seal of a
given size does not change in this model; any change in the average
consumption is due to a different age structure of the population. In fact,
this has changed very little since 1981 when the population was estimated to
be 2.5 million (not the 1.5 -1.8 million implied by the author) and 1994. In
bioenergetics models such as the ones Dave Lavigne and I constructed, the
energy requirements of the animal are estimated and then it is assumed that
they are met. The exact amount of food consumed will depend upon the energy
content of the prey. The author is correct in referencing the study done by
Dr. Lavigne to state that if seals ate only faty fish the amount consumed
would be lower than our estimate.  However, the same study also states that
if the diet included prey with lower energy content, the amount consumed
would be greater. Our estimate is based upon the composition of the diet
observed since 1982 in Newfoundland.

The author stated that the amount of cod estimated to have been consumed is
3.5 times greater than the amount of cod that existed (based upon assessments
by the Dept. of Fisheries and Oceans). It should be remembered that these
assessments are based upon offshore surveys of cod which are 3 years of age
or older while harp seals eat mainly 1 and 2 year old cod, often in inshore
areas. I have discussed this differnce with assessment scientists and
they all agree that there are no current estimates of the number of 1 and 2
year old cod in inshore areas. Therefore, the consumption estimates and
abundance estimates referred to are not comparable.

Finally, the article states that about a third of the harp seal population is
born in the Gulf. Traditionally this is true although the proportion can vary
from less than 20% to greater than 40% among years. Births occur in late
February and early March. Although some harp seals remain in the Gulf
throughout the summer (as seen by the author), the majority have left
for the summer feedng grounds in the Arctic by early July when the whale
surveys described occurred.

I hope this will clear up some of the misunderstandings which may occur from
this article. In order to have a rational discussion of the sceintific merits
of the any research, it is important that the reports of that research are
correct.


Garry Stenson
<END QUOTE>

--
Simen Gaure, Department of Mathematics, University of Oslo

From: steinn@sandy.ast.cam.ac.uk (Steinn Sigurdsson)
Newsgroups: sci.environment,talk.environment
Subject: Re: Seals and fish
Date: 19 Sep 95 10:19:55
Organization: IoA, Cambridge
Lines: 85

In article <43ab7c$9p1@noc.tor.hookup.net> adncstr@hookup.net (Anne Doncaster) writes:

   >    >In article <42vsb5$o26@inforamp.net> sbest@inforamp.net (Stephen Best) writes:

   >    >   I think I'm repeating myself but, again, I'm not aware that there is
   >    >   any evidence to suggest that "fewer seals CAN CAUSE more cod."  In
   >    >   fact, in an earlier post I mentioned a recent study published in
   >    >   Science (August '95) that indirectly supports this position.  Also,
   >    >   despite actively hoping and working to produce the evidence for some
   >    >   years, the Canadian Department of Fisheries and Oceans has not been
   >    >   able to conduct or find any research that would allow one to conclude

   >    >Regarding your advocacy of the Myers et al paper (Science August 25, 1995.
   >    >v. 269, p 1106-1109),

 ...
   >    Have you noticed that Science is a refereed journal?  And did you
   >
   > Yes, I have noticed. I was under the impression that Can Jo Fish was
   > also refereed.

   Could you send details on Garry Stenson's papers appearing in
   Can.Jo.Fish?

Nope. Haven't read it.

   >    >I would contend you are somewhat misrepresenting the results
   >    >of Myers et al.

   > As I discussed in the post, I would suggest you are misinterpreting
   > the result. Again I ask you, if recruitment to zero age cohort is
   > healthy, despite low levels of commercial stock - ie there is
   > no depensation as Myers et al contend - then how are the intermediate
   > age cohorts being depleted? What is precluding a rapid stock recovery
   > when recruitment is strong and spawning successful.

   Simon:  Have you read the Myer's paper.  I can't find anything in
   the paper that supports what you are saying.  He concludes that
   the depleted fish stocks that he et al studied, with one exception,
   all recovered to commercial levels.

That wasn't Simon, it was me.
I have read the paper, it is on my desk right now.
The fact that Myers concluded all stocks recovered is not
really pertinent to the impact of the seals (his one counter
example, Icelandic Herring, has I believe now recovered to
commercial hunting levels - if it is the herring stock I think
he refers to). - BTW there are instances of stocks that did
not recover at all, not discussed in that paper.

Let me repeat one more time what I understand Myer's paper says:

it says that depensation is not a factor for the 127 stocks they
looked at. That is to say, spawning (and recruitment to zero age
cohort) is strong, even when the breeding population is weak.
That is, if you deplete the mature fish you still get a lot of
new young fish. Hence, one would infer that the stocks should recover
rapidly even if the mature population is severly overfished.

However, not only did the stocks crash, they are not recovering fast,
they do recover eventually but more slowly than the time for the
current cohort to mature.

Now, the current issue is whether there is anything to be done
to help the stocks recover more rapdidly. One fact, not discussed
in Myer's paper, is that recruitment to older cohorts has been
weak, despite the strong spawning in at least two of last few years.

The question is left begging, why if there is no depensation
did the cod stock not recover rapidly?

   > Thanks, I have my own sources closer to home.

   Do your sources include original sources or are you getting this
   information second hand?  If the latter, I hope not from the
   Norwegian scientists who had such difficulty in calculating the
   numbers of minke whales?

I have no sources in Norway. I have no association with Norway and
in fact have never been there. My sources are "original" in that
I see some first hand published data on Atlantic fishery populations,
and know some of the people who have looked at both current management
and the general problem of optimising yields from fisheries.

From: steinn@sandy.ast.cam.ac.uk (Steinn Sigurdsson)
Newsgroups: sci.environment,talk.environment
Subject: Re: Seals and fish
Date: 28 Sep 95 18:42:58
Organization: IoA, Cambridge
Lines: 131

In article <43rl74$qi7@inforamp.net> sbest@inforamp.net (Stephen Best) writes:

   steinn@sandy.ast.cam.ac.uk (Steinn Sigurdsson) wrote:

   >   >   In article <432i2d$9ff@inforamp.net>, sbest@inforamp.net wrote:

   >   >     In fact, I would argue, honorable members of the jury, that it is the
   >   >     sea birds who are inhibiting the recovery of the cod.  They are a far
   >   >     larger predator, by orders of magnitude, of cod than the seals.  It is
   >   >     they who should have their numbers reduced.  Cull the gulls and
   >   >     puffins, I say.  They are the guilty ones.

   >   >   Please document.

   >   >Most amusing. I didn't realise there were orders of magnitude
   >   >more cod in the sea!

   >Perhaps you should. Remind us what the take (in mass)
   >of cod by seals is estimated at. Increase by orders of
   >magnitude and marvel.

   To remind you what the take (in mass) of cod by seals is would require
   producing a research document to support my figure, if I am to meet
 ...
   the figures that do exist are utterly unreliable, as admitted by those
   who generate them.

So remind us how you conclude then that other predators are
more important in the total take?

   you, but it might be helpful if I point out a problem in fisheries
   management which you yourself appear to have succumbed to: and that is
   measuring populations of fish species in terms of mass.  Have you ever
   wondered why this is done?  For example, in Canada commercial fish

Yes. It is because it is the most easily measured number.
Some places do make an effort to estimate number take as
well - it is easily done by sampling the take and finding
the mean and approximate distribution (remembering that legally
netted fish is bounded below in size).

   quotas are usually set by tonnage.  But taking a ton of sexually
   mature cod, for example, will likely have far greater impact on the
   production of spawn than taking a ton of sexually immature cod, but
   you must be aware of this.

You didn't understand a word of the Myers et al depensation
paper, did you? You are completely wrong for what it is worth,
since spawning success anti-correlates with stock at low stock,
it is important _not_ to take  the sexually immature cod, while
it is safe to take a large fraction of the sexually mature cod.
If the results are right.

 ...
   Your pedantic concern and amusing ridicule about my phrase "orders of
   magnitude" appears to come from this fundamental flaw in fisheries
   figures and management, which you may have either overlooked or not
   fully understood. Or perhaps there was a lack of clarity in my post.

I think there is a lack of understanding in you.
The fisheries figures are not flawed, they are simply
presenting the raw data as collected, which is by mass,
you seem to be assuming that the people involved have not
thought about this at all.

   I'm sure you can see that the same confusion results when dealing with
   predators and, indeed, not only managing them but also fully
   understanding their effects on species that humans find, from time to
   time, more economically desirable.  A small predator, such as a bird,
   may take far more (numerically) small individuals of a prey species
   such as cod, than a large predator such as a marine mammal.  Indeed,
   until the measurements are actually done or produced by someone who
   would like to the literature search for you, one could surmise that it
   is possible that even the mass of cod consumed by sea birds exceeds
   that consumed by harp seals.  Let me take one moment to further help
   you in understanding this with a completely hypothetical example.

So you are also innumerate...
 ...

   I hope you find the above explanation as useful as I found your
   analysis of my statement.

Oh, I do hope not.

   As you seemed to have missed my point which was probably a result of a
   poorly worded post on my part.  My mention of sea birds was to simply
   point out that harp seals are not the only predator of cod.  And that
   if a reduction of predators is to be considered, because it is
   believed that this will improve the recovery of cod stocks, then
   shouldn't other predators of cod, perhaps predators that might have a
   greater impact, be considered as well by fisheries managers?

They are. You seem to have assumed that my examples were
hyopthetical. I gather the IWC does not concern itself
with gulls and puffins or you would know that.

   I realize that there is no market at present for Kentucky Fried
   Puffins, but perhaps one could be developed to give the people of
   Newfoundland something to do.  I mean serving up roasted male puffins
   is just another type of cock selling, isn't it?

Say what? Is this another of your penis obsessions?
Puffins are a rather tasty and eminently sustainably coastal
resource that is currently exploited. Go figure.

   >So, will the IWC advocate a cull of puffins and gulls now?
   >Perhaps a bounty on gulls would be appropriate?

   Is there any evidence to support the hypothesis that "less puffins and
   gulls = more cod" or, as Dr. Orenstein is compelled to remind, any
   model by which this statement could be properly tested?

You just presented this as an hypothesis, I noted its consequences.
I seriously doubt whether there is any model that could dissuade the
theologians of the IWC from their convictions, but since you ask,
yes there are models, and no I don't know how valid they are.

   >And puffins are good eating...


   ... particularly, when spiced with puffery.

Actually, no, they are best steamed. The meat is already
strongly flavoured. But then you don't actually know anything
about what goes on in the North Atlantic.

From: Simen.Gaure@math.uio.no (Simen Gaure)
Newsgroups: sci.econ,alt.politics.economics,sci.environment,tx.general,
	tx.politics
Subject: Re: Collapse of the fisheries.
Date: Thu, 21 Mar 1996 11:18:59 +0100

Commenting on myself:

In article <Simen.Gaure-2003961554390001@mattemac1.uio.no>,
Simen.Gaure@math.uio.no (Simen Gaure) wrote:

  Hmm, I think seals in that area prefer cod of the 1 and 2 year classes.
  Research by Canadian DFO shows that (G. Stenson).
  Cannibal cod is usually older than that, someone has told me.
  Anyway, Lavigne and Meisenheimer could apparently not find any
  support in reality for this theory, so they have now replaced
  cannibal cod with squid as the dominant predator.
  At the same time, the New Scientist article, and Meisenheimer, claims
  that science shows that predators have no effect on the recovery of the
  cod at all  (See e.g. his "Seals, Cod, Ecology and Mythology" report
  available from IMMA (http://www.imma.org)).
  Quite interesting reading, and it's all completely logical
  in the context of IFAW's continuing campaign to put an end to
  seal hunt worldwide.

I wrote a little piece on this a couple of weeks ago, before
New Scientist published their article (March 16) on this.  I posted it
to some newsgroups, including sci.bio.fisheries and soc.culture.canada.
Here it is, in slightly revised form:

A lie is born  (Ammonites and Moabites)
=======================================

As described in "Super Whales" by Arne Kalland (11 Essays on Whales
and Man, High North Alliance 1994), the creative construction
of myths is important in some areas of modern animal protectionism.
During the fall of 1995 I witnessed the early stages of a
myth creation.  Unfortunately I wasn't aware of it then, but here's
the story.


August 25, 1995:  Volume 269 of the scientific journal "Science" hits
the streets.  On pages 1106--1108 it contains an article with the title
"Population Dynamics of Exploited Fish Stocks at Low Population Levels"
by Ransom Myers et al.
The article investigates a particular phenomenon in fish stocks known
as "depensation".  Normally, if a natural population of animals is reduced
for some (external) reason, the reproductive success of each individual is
not affected, or increases.  This means that the population will be
able to recover to its previous size should the reason for the decline
disappear.
Depensation is when this fails, i.e. when the reproductive success
declines when the population is reduced. This can be disastrous for the
population's ability to recover.
The article concludes that depensation is not a big problem, i.e. that
fish stocks depleted by overfishing generally have the *potential* for recovery
once the overfishing ceases.  However, the article says nothing about
the speed of recovery, nor about factors affecting the speed,
simply because the methods they use don't convey such information.

So far, so good.
There's nothing mystical, mythical or anecdotal about this.

However, the myth's created in a particular context.
Cod stocks in Newfoundland have been severely depleted by overfishing.
All fishing has now been stopped.  An alternative to fishing is
to hunt seals for food and fur, and Newfoundlanders do this,
as they have done for a very long time.
(See e.g. <http://www.ncr.dfo.ca/communic/seals/understa/under_e.htm> )

It is known that seals are preying on the depleted
cod populations.  The seal population is growing.
It is feared that a growing seal population may slow down
the recovery of the overfished cod stocks.  Currently
this has not been fully investigated, so little concrete is known about it.
Research is going on to get a better understanding of the ecological
interactions in the area.

This scientific vacuum can be filled with speculations.
How can the article described above be utilized by the
merchants of science?  The following is an example.

September 8: Opportunists have chewed on the Science article mentioned
above for a fortnight or so, and found that it can be used in their
struggle to bring an end to the Canadian seal hunt.  Animal welfare groups
which oppose seal hunt on ethical grounds now have concocted an interpretation
of the article to counter the contention that seals may slow down
recovery of depleted fish stocks.  And, at the same time, they manage to
cast doubt on all possible future findings supporting such a theory.

The Vice President of the "International Wildlife Coalition" (IWC) in the
Internet newsgroup sci.environment:

   "The paper "Population Dynamics..." is evidence that the equation
   'less seals = more cod' is probably not valid, despite its obvious
   appeal to many. The researchers examined two questions.  Do low
   population levels prevent recovery of depleted fish stocks?  And does
   a large number of predators prevent populations from rebounding?
   Predators, in this case, means the whole range of predators from
   seabirds, to seals and other marine mammals, to other fish species.
   The researchers [...] could not conclude that
   either low population numbers or the presence of predators prevented
   or inhibited the recovery of a stock. [...]
   Clearly, the best evidence to date suggests that an increased cull of
   seals (or any other predator of cod) is not necessary to hasten the
   recovery of the cod stocks."

At that time I had not read the article, nor am I an expert in this field,
so I asked the VP how the authors explain why reduction of human fishing
would hasten the cod recovery, while reduction of other predation has no
such effect.  Insult was the response.

The following week more people questioned the VP's interpretation.

September 16: The VP responds

  "We also checked this interpretation out with the International Marine
   Mammal Association in Guelph Ontario.  This is Dr. David Lavigne's, a
   University of Guelph professor and one of the world's leading marine
   mammal experts and recognized as the authority on harp seals, independent
   research facility."

Here we have something.  An independent research facility,
leading experts, an authority and all.

For those who know more than the average it is known that IMMA is far from
being an independent research facility: IMMA is an affiliate of IFAW, the
International Fund for Animal Welfare, and IFAW is IMMA's primary funder.
IFAW has been profiting on anti-sealing campaigns for 20 years and brag
about being responsible for the European Union's ban on the importation of
seal products.  Thus, IWC's use of IMMA in animal welfare issues
has been figuratively described in ancient jewish literature (Genesis 19:31-36).
However, I didn't know about IMMA's connection with IFAW at
that time, so my alarm bells didn't ring (nor any other of my bells for
that matter.)

Anyway, I got entangled in other, more interesting work.
A couple of months later, encouraged by a marine biologist who had
followed the debate, I finally got around to read the Science article.  I
had forgotten IMMA, instead I consulted fishery biologists who were not
funded by IFAW.

I found that IWC does not have any foundation for their interpretation.
The article doesn't deal with the rate of recovery of fish stocks, only
with their theoretical potential for recovery.  Another point is that
the presence of depensation is a serious sign that something is wrong, but
the lack of depensation doesn't necessarily mean that all is well.
That is, the erroneous interpretation is a case of the classical
logical fallacy termed "affirming the consequent", or "reversing the
arrow" as we loosely say in my field.

I told IWC about their misinterpretation in a private letter.
They responded with insult.  I posted my criticism to the
same forum where the original interpretation appeared.  No response.
I took a break from all this, and reviewed the discussion so far.

Then I looked at what IMMA presents.  It transpired that they have released
a Technical Briefing called "Seals, cod, ecology and mythology" in which
it is written

  "[...] the prestigious journal
  Science published a study [...] in which it
  is concluded that predators (including seals) generally play no
  discernible role in the population dynamics of recovering fish stocks
  (including cod) (Myers, et al. 1995)."

January 1996:
I write privately to the author and explain to him that his interpretation
is wrong, to accentuate this I point him to a contradiction in his own
report, namely that he also claims that seals may have a positive impact
due to them preying on predators of cod.  That is, he both claims that
predators (seals in particular) have no impact and that there may be other
predators (fish?) which have an impact.  Insult ensues.

I decide to go public with my criticism, the only question is how and
where.  Then, in January, Georg Blichfeldt of the High North Alliance sends
an enquiry (January 27) to the electronic mailing list of the world's
marine mammal scientists, MARMAM.  Mr. Blichfeldt has attended a European
Parliamentary hearing where Dr. Lavigne of IMMA/IFAW among other things
has suggested that a reason for the slow recovery of Newfoundland cod isn't
seals, but rather that cod are cannibals, i.e. that cod preying on cod
slows down cod recovery, and that seals, by eating cannibalistic cod
actually help the cod population to recover.  Blichfeldt wants to know
whether anybody can shed some light on this novel theory of Lavigne's.

Unfortunately I can not, but I point MARMAM readers to the contradiction
that IMMA already wants us to believe that predators play no role, so they
can't logically claim that some predators actually play a role.  IMMA
responds in a non-material way, but they confirm that IFAW is their
primary funder.  I repeat my criticism in different words
(February 16), detailing what is wrong with their interpretation of the
Science article, hoping they will respond so that we can have
a debate.

This time there's no response.  No insult, no nothing.

I don't know whether this is the end of the story, I hope so, but I fear
that too many people have already read IMMA's misrepresentation and copied
it, because they trusted IMMA.  As far as I've seen, IMMA has done
nothing to alleviate the situation.  The Technical Briefing 95-01 "Seals,
cod, ecology and mythology" is still available unaltered from IMMA.

I've seen statements linking "a recent article in Science by Myers et al"
to the seal/cod discussion several places, and I expect to see it in more
places in the future.  I wonder how many people will take this interpretation
as the truth, and what they will think if, after thorough examination of
the seal/cod interaction, it turns out that seals do indeed have an impact.
Who will be accused of cheating?


Whenever you see a reference to an article by Myers et al in Science,
August 1995, which purportedly shows that seals have no effect on cod
populations, you now know that this interpretation is an anecdote, and you
know how and where the anecdote originated.

I'm interested in tracing how this anecdote spreads, so if you come
across it, please drop me a letter stating when and where you found it.

Incidentally, you also know that Dr. David Lavigne's independent
research facility, the International Marine Mammal Association isn't
independent at all, but rather very dependent upon the money from
an advocacy group by the name of the International Fund for Animal Welfare.

The fate of Lavigne's cannibal theory is also open, IMMA didn't respond
to Blichfeldt's enquiry.  Nor did anybody else.



Oslo, March 7, 1996

Simen Gaure  <Simen.Gaure@math.uio.no>

--
Simen Gaure, Department of Mathematics, University of Oslo