[NatureNS] Why save the Red Knot? - vertebrate hegemony?

From: "Roland McCormick" <roland.mccormick@ns.sympatico.ca>
To: <naturens@chebucto.ns.ca>
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Date: Thu, 14 Feb 2008 13:41:59 -0400
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I read in the paper recently that one of the boys I taught in school was 
fined a couple of thousand dollars for using crabs as bait to catch lobster. 
I wondered about that at the time because I had never heard about using them 
for bait before, or the reason for the fine.  I assume that is what we are 
talking about here, and that there is a good reason for it.  I can assure 
you that if this is true the fines are a good deal more than $25.

Roland.
----- Original Message ----- 
From: "Paul S. Boyer" <psboyer@eastlink.ca>
To: <naturens@chebucto.ns.ca>
Sent: Thursday, February 14, 2008 11:26 AM
Subject: Re: [NatureNS] Why save the Red Knot? - vertebrate hegemony?


> The horseshoe crab is a living fossil, virtually unchanged since the 
> Jurassic Period (in the middle of the Age of Reptiles).  Tracks of 
> spawning horseshoe crabs have been found in Devonian rocks of 
> Pennsylvania, which are far, far older.  Fossil relatives are found  in 
> Manitoba from the Ordovician Period, about 445 MY old.
>
> There are only a few species of horseshoe crabs in the world (the 
> American one, the subject of the program, and three minor Asian  species). 
> The American horseshoe crab is the largest and the most  numerous, and the 
> most spectacular to watch. New Jersey is the center  for their abundance 
> and average size, or at least it used to be.
>
> It is not the medical use that threatens the population, but the  wasteful 
> and (IMHO) lunatic use of horseshoe crabs as bait, or even  fertilizer.  I 
> have not checked recently, but when last I looked an  annual license to 
> take unlimited numbers of horseshoe crabs (seized  from the beaches while 
> they are trying to spawn) was a mere $25.   Horseshoe crabs have a long 
> lifespan, and do not recover quickly from  the depredation of being hauled 
> away in truckloads.  Actually, the  Red Knot probably can increase its 
> numbers faster with environmental  change than can the horseshoe crab, 
> because the generation time is  shorter for the Knots.
>
> On 14 Feb 2008, at 2:04 AM, Stephen Shaw wrote:
>
>> Unfortunately missed the program, but I had a mild comment on the 
>> species-ist
>> emphasis here (sent it earlier but it didn't do through).
>>
>> Nothing against the Red Knot and of course I hope it survives, but  the 
>> received
>> vertebratocentric perspective on this is interesting.  As the blurb 
>> below
>> states,
>> there are lots of other similar peep species around, but the  horseshoe 
>> "crab"
>> Limulus polyphemus is a unique species here and has been  practically 
>> wiped out
>> in many of its former habitats on the US East coast, according to  Bob 
>> Barlow, a
>> former student of Hartline (see below) who still works on it,  latterly 
>> on its
>> visual behaviour under water. Apparently the market for its blood  is the 
>> main
>> reason for the punitive "harvesting".
>>
>>  Besides having a far more interesting, ancient lineage, Limulus has
>> contributed to several outstanding scientific discoveries in vision 
>> science,
>> notably that of "lateral inhibition" by which the nervous system 
>> sharpens up
>> percepts, enhancing edge-detection in images.  This has emerged as a
>> common enhancing operation elsewhere in nervous systems, but  originally 
>> came
>> mainly out of work on the compound eyes of Limulus in the 40s-60s  --  
>> netting a
>> Nobel prize for H.K. Hartline, of the then Rockefeller Inst (now  Univ). 
>> In the
>> 60s, S. Yeandle made the first recordings of single photon captures  in 
>> the same
>> eye (since then recorded in vertebrates, though not in Red Knots),  while 
>> in the
>> 70's, the first detailed analyses of how photoreceptor currents work
>> (semi-universal) came out of measurements on huge photoreceptor  cells in 
>> the
>> ventral nerve that had been thought before this to be an olfactory 
>> structure
>> (analysed since in vertebrates, though not in Red Knots).   Circadian 
>> rhythm
>> mechanisms are big news at present (molecular mechanisms), and one  of 
>> the best
>> analyses of the circadian control of an eye by the brain came from 
>> Barlow and
>> colleague's work on the Limulus lateral eyes.  There are at least  two 
>> other
>> sets of eyes in horseshoe crabs, one UV sensitive and one in the 
>> telson...
>>
>> None of these conceptual advances were minor cul-de-sacs and all  have 
>> become
>> incorporated into the neuroscience base, ever expanding. Limulus 
>> deserves great
>> respect as a unique and unusual pioneer invertebrate animal that  ought 
>> to
>> survive.  What has the Red Knot done to gain comparable respect?
>>
>> So, if I had to curry up votes for one of the two endangered  species, it 
>> would
>> be for the unique and illustrious horseshoe crab, first.  "Why save  the 
>> Red
>> Knot?" indeed -- do it second.
>> Steve
>> ******************************************
>>
>>
>> Quoting Elizabeth Doull <edoull@ns.sympatico.ca>:
>>> Why save the Red Knot?
>>> PBS
>>> flocks of shorebirds, the red knot is fairly average looking. In  fact, 
>>> only the most practiced bird watchers may be able to  distinguish this 
>>> medium-sized, plump peep from the thousands of  other shorebirds playing 
>>> tag with the waves. Yet, somehow the red  knot has caught the attention 
>>> of people around the world.
>>>
>>> The knot's dependence on the eggs of the heavily harvested  horseshoe 
>>> crab has placed it at odds with another species --  humans. Conservation 
>>> groups, lawmakers, fishermen, scientists, and  ordinary citizens have 
>>> all entered the debate. But even as our  actions have imperiled the red 
>>> knot, we can also preserve the  species, by regulating the fishing 
>>> industry and keeping clear of  the beaches that the knots rely on during 
>>> migration. Where nature  ranks in our system of values will dictate how 
>>> far we are willing  to go to protect the red knot.
>>>
>>> There are millions of shorebirds in the world. Why all the clamor  over 
>>> the red knot? How co