[Cnidaria] Re: Cnidaria Digest, Vol 43, Issue 17
Nando Boero
boero at unile.it
Mon Nov 26 07:51:12 PST 2007
If you take the volume II of FS Russell on The Medusae of the British
Isles and you go to page 85 you will find a paragraph on the Swarming
of Pelagia around the British Isles (you can download it here: http://
www.mba.ac.uk/NMBL/publications/medusae_2/medusae_2.htm). He reports
this:
Cole (1952) recalled astonishing numbers in Port Erin Bay, Isle of
Man, in october 1899 (the present event is in November, so it is not
so different; my note) when "the sea looked as if converted into a
solid mass of jellyfish".
Hunt (1952) recorded the occurrence of about sixty specimens in the
estuary of the river Yealm, South Devon, in December 1951. Fraser
(1954) recorded Pelagia in 1953 off Shetland, Fair Isle, west of
Orkney, and in the North Sea, east of 1° W at times "in sufficient
numbers to cause inconvenience to fishermen".
So, the occurrence of Pelagia in northern waters, in the winter, is
not so exceptional. Then, if you ask why a southern species is
present massively at northern latitudes, maybe one explanation might
be global warming, right?
These things happened already in the past, but very few studies are
dedicated to gelatinous plankton, unless its presence is particularly
obnoxious, then it is forgotten until the following event.
It is a widespread opinion that the removal of large fish from
trophic networks (due to fisheries) is leaving space to other top
predators that are not affected by fisheries: the gelatinous
predators. We are providing the proper conditions to their
development by removing their competitors.
We thought that we can deplete the resources of the ocean and then we
can have more production by pursuing aquaculture. Big mistake. Salmon
are usually not killed by pelagia swarms, they can swim away (but
their larvae and juveniles do not escape, though). But if they are in
a cage, then they are stuck there, and die. They should have been
released when the swarm was first noticed. But who does look at
jellyfish swarms?
Another question is: what can we do? the answer is straightforward:
nothing. What can you do to stop hurricanes? But then, yes, there are
things we might do. Restore trophic networks, allowing for the growth
of larger fish, instead of taking them all. Re-consider aquaculture:
we rear carnivores, and we feed them with fish that we take from
natural populations. This is ecologically crazy. Or we try to
transform carnivores into herbivores, feeding them with soja (on land
we tried to transform herbivores into carnivores, hence the mad cow
disease). This is affecting ecosystems in a way that is conducive to
jellyfish blooms all over the world. We are going back to a pre-
cambrian ocean. But these answers are not nice to hear. A change in
our research strategies is badly needed. But if I say these things
here, I am preaching to the priests...
all the best
nando
Ferdinando Boero
DiSTeBA (Dipartimento di Scienze e
Tecnologie Biologiche e Ambientali)
Universita' del Salento
73100 Lecce
Italy
Voice: -39 0832 298619
Handphone: 3332144956
Fax: -39 0832 298702 or 298626
email: boero at unile.it
http://homepage.ntlworld.com/andymurkin/Resources/MusicRes/ZapRes/
natphen.html
VISIT AQUATIC BIOLOGY:
http://www.int-res.com/journals/ab/ab-home/
VISIT ITALIAN JOURNAL OF ZOOLOGY:
http://www.tandf.co.uk/journals/titles/11250003.asp
On 26/nov/07, at 12:3812:2, cnidaria-request at uci.edu wrote:
> Send Cnidaria mailing list submissions to
> cnidaria at uci.edu
>
> To subscribe or unsubscribe via the World Wide Web, visit
> https://maillists.uci.edu/mailman/listinfo/cnidaria
> or, via email, send a message with subject or body 'help' to
> cnidaria-request at uci.edu
>
> You can reach the person managing the list at
> cnidaria-owner at uci.edu
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Cnidaria digest..."
>
>
> Today's Topics:
>
> 1. FW: reasons for invasion of Pelagia noctiluca in Northern
> Ireland / Scotland (Richard Lord)
> 2. RE: FW: reasons for invasion of Pelagia noctiluca inNorthern
> Ireland / Scotland (Doyle, Tom)
> 3. F. Pag?s thesis & paper copy request
> (jessica.frost at uni-hamburg.de)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 25 Nov 2007 20:54:57 -0000
> From: "Richard Lord" <fishinfo at guernsey.net>
> Subject: [Cnidaria] FW: reasons for invasion of Pelagia noctiluca in
> Northern Ireland / Scotland
> To: "'Cnidaria Newsgroup'" <cnidaria at uci.edu>
> Message-ID: <000601c82fa5$75b95a50$6802a8c0 at FISHWORK>
> Content-Type: text/plain; charset="us-ascii"
>
> Mr. Matthew G. Longman sent me the email below and was happy for me to
> forward it to the cnidaria email list. Would experts in scyphozoa
> blooms
> kindly offer explanations of why over the last few weeks immense
> numbers of
> small Pelagia noctiluca have invaded waters of Ireland and Northern
> Ireland
> and now the west coast of Scotland. Is the November timing of the
> bloom
> unusual and particularly at this northern latitude?
>
>
>
> Best wishes,
>
> Yours sincerely,
>
> Richard
>
> Richard Lord
>
> Guernsey GY1 1BQ
>
> Great Britain
>
>
>
> Tel: 01481 700688
>
> Fax: 01481 700686
>
> Email: fishinfo at guernsey.net
>
> http://www.sealordphotography.net <http://www.sealordphotography.net/>
>
>
>
> -----Original Message-----
> From: Matthew Longman [mailto:mlongman at csf.edu]
> Sent: 25 November 2007 02:54
> To: fishinfo at guernsey.net
> Subject: mauve rarity
>
>
>
>
>
> Mr. Lord...
>
> i am a student researching environmental rarities and i would like
> to know
> some things about the recent news concerning mauve stinger and compass
> jellyfish swarming around the British Isles. The articles i have read
> pointed out that seeing these particular jellyfish in these areas is
> abnormal for winter months. is there any reason particular why these
> jellyfish would be in this area in such numbers? if you are unsure
> of any
> reasons, please refer me to someone who may know. thank you.
>
> sincerely, Matthew G. Longman.
>
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: http://maillists.uci.edu/mailman/public/cnidaria/attachments/
> 20071125/224b0a82/attachment-0001.html
>
> ------------------------------
>
> Message: 2
> Date: Mon, 26 Nov 2007 08:54:30 -0000
> From: "Doyle, Tom" <t.doyle at ucc.ie>
> Subject: RE: [Cnidaria] FW: reasons for invasion of Pelagia noctiluca
> inNorthern Ireland / Scotland
> To: "Cnidaria Newsgroup" <cnidaria at uci.edu>
> Message-ID:
> <C918D8F06771A8438E3C4DEE9D82BA9BD8000F at EXCH1.central.ad.ucc.ie>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Matthew,
>
> Pelagia is more typical of warmer waters but does regularly occur
> in our waters during October-December when it is carried up here
> via the Jet Current (a current that runs up along the Bay of Biscay
> and off the west coast of Ireland). So its not unusual to see
> Pelagia at this time of the year, however, it is probably unusual
> to see such numbers and such widespread occurrence i.e. offshore,
> west + north coast of Ireland and now Scotland (do you know where
> in Scotland they are washing up?). How far they head north depends
> on the strength of the Jet current, which varies from year to year,
> and so is probably very strong this year. There are records of
> Pelagia washing up in large numbers off the coast of Ireland going
> back 100 years (Delap sisters), more recent reports off the west
> coast of Ireland (1998), and in 1966 (or around this year) enormous
> numbers were reported in the Irish Sea. Hope this helps,
>
> All the best,
>
> Tom.
>
> Thomas K Doyle, PhD
> Coastal and Marine Resources Centre
> University College Cork
> Glucksman Marine Facility, Naval Base
> Haulbowline, Cobh
> County Cork
> Ireland
>
> Tel: 00353 21 4703119
> Fax: 00353 21 4703132
> Email: t.doyle at ucc.ie
>
>
>
> -----Original Message-----
> From: cnidaria-bounces at uci.edu [mailto:cnidaria-bounces at uci.edu]On
> Behalf Of Richard Lord
> Sent: 25 November 2007 20:55
> To: 'Cnidaria Newsgroup'
> Subject: [Cnidaria] FW: reasons for invasion of Pelagia noctiluca
> inNorthern Ireland / Scotland
>
>
>
> Mr. Matthew G. Longman sent me the email below and was happy for me
> to forward it to the cnidaria email list. Would experts in
> scyphozoa blooms kindly offer explanations of why over the last few
> weeks immense numbers of small Pelagia noctiluca have invaded
> waters of Ireland and Northern Ireland and now the west coast of
> Scotland. Is the November timing of the bloom unusual and
> particularly at this northern latitude?
>
>
>
> Best wishes,
>
> Yours sincerely,
>
> Richard
>
> Richard Lord
>
> Guernsey GY1 1BQ
>
> Great Britain
>
>
>
> Tel: 01481 700688
>
> Fax: 01481 700686
>
> Email: fishinfo at guernsey.net
>
> http://www.sealordphotography.net <http://www.sealordphotography.net/>
>
>
>
> -----Original Message-----
> From: Matthew Longman [mailto:mlongman at csf.edu]
> Sent: 25 November 2007 02:54
> To: fishinfo at guernsey.net
> Subject: mauve rarity
>
>
>
>
>
> Mr. Lord...
>
> i am a student researching environmental rarities and i would like
> to know some things about the recent news concerning mauve stinger
> and compass jellyfish swarming around the British Isles. The
> articles i have read pointed out that seeing these particular
> jellyfish in these areas is abnormal for winter months. is there
> any reason particular why these jellyfish would be in this area in
> such numbers? if you are unsure of any reasons, please refer me to
> someone who may know. thank you.
>
> sincerely, Matthew G. Longman.
>
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: http://maillists.uci.edu/mailman/public/cnidaria/attachments/
> 20071126/d678fb16/attachment-0001.html
>
> ------------------------------
>
> Message: 3
> Date: Mon, 26 Nov 2007 12:33:49 +0100
> From: jessica.frost at uni-hamburg.de
> Subject: [Cnidaria] F. Pag?s thesis & paper copy request
> To: cnidaria at uci.edu
> Message-ID: <1196076829.474aaf1dd08f0 at webmail.rrz.uni-hamburg.de>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Greetings Fellow Researchers,
>
> This email is a rather difficult and awkward one to write as it
> leaves me
> reminded of sadness. I am searching for a copy of Francesc Pagés'
> PhD thesis
> from the University of Barcelona (1991) on the "Ecology and
> Systematics of
> Planktonic Cnidarians of the Benguela Current" (it is ok if it is
> in Spanish),
> as well as his paper in the South African Journal of Zoology (1992)
> "Influence
> of the thermocline on the vertical migration of medusae during a
> 48h sampling
> period". If anyone can provide a pdf of each, it would be much
> appreciated. I
> know that Francesc was dear to many of us, and, for me in
> particular, he was
> not only a generous and kind colleague but a fantasticly supportive
> mentor, a
> rarity these days!
>
> All the Best,
> Jessica Frost
>
> University of Hamburg
> Institute for Hydrobiology and Fisheries Science
> Grosse Elbstrasse 133
> 22767 Hamburg
> jessica.frost at uni-hamburg.de
>
>
> ------------------------------
>
> _______________________________________________
> List-Info: https://maillists.uci.edu/mailman/listinfo/cnidaria
>
>
> End of Cnidaria Digest, Vol 43, Issue 17
> ****************************************
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://maillists.uci.edu/mailman/public/cnidaria/attachments/20071126/5775cef8/attachment-0001.html
More information about the Cnidaria
mailing list