GLOBALJMBA

marine environmentSUMMER 2005 Issue 2

Also in this issue:DECLINE OF A DOVER STRAIT HARBOUR SEAL

TEMPERATURE EFFECTS ON MOON JELLYFISH

ICONOGRAPHY AND JELLYFISH EVOLUTION

ANGLERFISH FEEDING IN THE SHETLANDS

JELLYFISH INVADE POWER STATIONS

CTENOPHORES IN THE BLACK SEA

HUMAN JELLYFISH INTERACTIONS

UNIQUE SCALLOP GARDEN

CLIMATE CHANGE & FISH

LIFE ON LIVING ISLANDS

LITTLE WHITE OCTOPUS

FISH LICE ON COD

THE PURPLE CLAM

Reproduction insharks and rays

The complex world

of siphonophores

JELLYFISH MAY

BENEFIT FROM

GLOBAL CHANGES

how many dolphins are left?

GLOBAL NEWSTsunami and Needlefish

24 JMBA G lobal Marine Environment

f you think of a dominant predator in the sea, youprobably imagine a shark, killer whale, or perhaps agiant squid. Unless you are a marine biologist (or a

species of zooplankton), you probably would notthink of – or perhaps even know of – thes iphonophores . These planktonic cnidarians ,however, have a much greater ecological effect thantheir better-known counterparts . There may be nomovies featuring s iphonophores , but they are amongthe most abundant and effective carnivores in thesea.

S iphonophores are hydrozoans , related to jellyfishand corals , but they aren’t radially symmetric as youmight expect a cnidarian to be. They are elongateand in many ways bilaterally symmetrical, taking oncomplex forms that look strange even among othermarine invertebrates . The most s imilar animal mightbe a hydroid, growing along a rock and sproutingpolyps , but which suddenly takes to the watercolumn. E ach s iphonophore is a colony cons isting ofa few bas ic types of zooids attached in manyrepeating series along a central s tem. Zooids havespecialized functions and are arranged like alocomotive, usually with propuls ion at one end, andfeeding, protective, and reproductive units trailingbehind. Through the central s tem, food can beconveyed from the ‘feeding cars ’ (gastrozooids) along

the length of the train and distributed to the rest ofzooids . Most species grow by adding ‘cars ’ justbehind the train engine (nectophores). This allowsthem to reach great lengths : they range in scale fromabout a centimetre to more than 10 metres . In fact,the species P raya dubia may be the longest organismon earth.

S iphonophores are unique in many ways . Typically,each gastrozooid has its own tentacle and can catchand process prey independently. Therefore as thelength and number of tentacles increase, thepredatory impact of an individual is multiplied by thearea of this long curtain of continuously fishingtentacles . S ome species even use a variety of tricksto lure prey directly to their s tinging cells . E venhumans would do well to avoid the species withblack, purple, or green colouration — these areusually fish-eaters , and while they won’t kill you, theirsting is powerful enough to penetrate through latexgloves . On the other hand, you would be lucky to seeone because these are typically found deeper than500 metres . Most s iphonophores are bioluminescent,and they can produce dramatic light shows whendisturbed. S ome, including many newly discovereddeep-sea species , are fluorescent, iridescent, orcapable of blanching to a milky white (or all of theabove!).

IF S IP HONOP HOR E S AR E S O S P E C IAL, WHY HAVE MANY P E OP LE NE VE R HE AR D OF THE M? UNLIK E THE P OR TUG UE S E

MAN O’ WAR — A NON-R E P R E S E NTATIVE S P E C IE S WHIC H HAS C OME TO R E P R E S E NT THE G R OUP IN MOS T

TE XTB OOK S — MOS T TY P E S AR E FOUND B E LOW THE S UR FAC E , AND AWAY FR OM THE C OAS T. THE Y AR E E XTR E ME LY

FR ANG IB LE , B R E AK ING APAR T IN NE TS OR WHE N ME R E LY ILLUMINATE D, AND THE Y R E QUIR E S P E C IAL ME ANS OF

C OLLE C TION, S UC H AS B LUE -WATE R S C UB A DIVING OR S UB ME R S IB LE S .

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� �S teven H.D. Haddock and C asey W. Dunn

E mail: haddock@mbari.org

I

Bluewater SCU BA diving to collect siphonophores

Erenna richardi

S iphonophores have not always been so esoteric :the most famous biologists of the 19th centurypondered and debated their s tructures and origins .Later marine biologists directed their efforts towardlarge-scale and rapid trawling, methods which arepoorly suited to returning intact specimens ofgelatinous taxa. Our knowledge of s iphonophoretaxonomy would have stagnated during the last 70years if not for the work of two B ritish scientis ts . A.K .Totton described numerous species during the 1940sand 1950s , but even more importantly, hesynthes ized, summarized, and organized what wasknown about the group in his monograph of 1965.S ince the 1980s , P hil P ugh has incorporated hisnumerous species descriptions into influential paperswhich examine and clarify entire s iphonophorefamilies . This month, with P ugh’s involvement in his25th and 26th species descriptions , he becomes themost prolific s iphonophore taxonomist ever. With theapplication of molecular genetics and greater accessto the deep sea, we head to a future filled with ins ightinto the evolution, relationships , and development ofthese unique superorganisms.

Further reading:Totton, A.K ., 1965. A S ynopsis of the S iphonophora. B ritish Museumof Natural History, London. K irkpatrick, P.A. & P ugh, P.R ., 1984. S iphonophores and velellids : keysand notes for the identification of the species . Linnean Society ofLondon, London. Mackie, G .O., P ugh, P.R . & P urcell, J .E ., 1987. S iphonophore biology.Advances in Marine Biology, 24, 97-261. Haddock, S .H.D., 2004. A golden age of gelata: past and futureresearch on planktonic ctenophores and cnidarians . Hydrobiologia,530/531, 549-566.Haddock, S .H.D., C .W. Dunn, P.R . P ugh. and C .E . S chnitzler., 2005.

309:263B ioluminescent and red-fluorescent lures in a deep-sea s iphonophore.Science.

Physophora hydrostatica

Praya dubia

Lilyopsis fluoracantha

Physalia physalis

Published in JMBAP ugh, P.R . 1992. The status of the genus Prayoides(S iphonophora: P rayidae). J MB A 72, 895-909.P ugh, P.R . & P agès , F. 1993. A new species of Clausophyes(S iphonophorae, C lausophyidae), with a redescription of C .galeata and C . moserae. J MB A 73, 595-608.P ugh, P.R . & Harbison, G .R . 1986. New observations on a rarephysonect s iphonophore, Lychnagalma utricularia (C laus , 1879).J MB A 66, 695-710.P ugh, P.R . & Youngbluth, M.J . 1988. A new species ofHalistemma (S iphonophora, P hysonectae, Agalmidae) collectedby submers ible. J MB A 68, 1-14Haddock, S .H.D., Dunn, C .W. & P ugh, P.R ., 2005. Areexamination of s iphonophore terminology and morphology,applied to the description of two new prayine species withremarkable bio-optical properties . J MB A 85(3), 695–707

0

2

4

6

8

10

12

14

16

1750

-18

10

1830

1850

1870

1890

1910

1930

1950

1970

1990

Carré, Stepanjants, Margulis

Bigelow

Total: 162

Val

id s

pec

ies

des

crib

ed

Decade beginning

The Chronology of Siphonophore Taxonomy

Haeckel, Chun

Quoy & Gaimard

AUTHOR: Totton PughVarious