Luis Ma ell1, Joan J So o-Angel1,
E lend Halla en1, Sanna Majane a2,
Aino Hosia1
QUICK IDENTIFICATION GUIDE
SIPHONOPHORES AND HYDROMEDUSAE
(CNIDARIA: HYDROZOA)
REPORTED AS HARMFUL FOR FINFISH
AQUACULTURE IN THE NORTHEAST
ATLANTIC
1Uni e si y Museum o Be gen, Depa men o
Na u al His o y, Uni e si y o Be gen, No way
2Ak aplan-ni a, No way
Con ac : Luis.Ma [email protected]
Body wi h ypical jelly ish shape
(hyd omedusae)
Table o con en s
IMPORTANT: This guide co e s all pelagic hyd ozoans epo ed as ha m ul o aquacul u e in
No heas A lan ic wa e s. Howe e , as >100 o he non-ha m ul species occu in he egion,
de ini i e iden i ica ion o specimens may equi e expe ad ice and b oade ID esou ces. 2
Lizzia blondina
page 3
Obelia spp.
page 6
Phialella quad a a
page 5
Solma is sp.
page 7
Velella elella
page 8
Apolemia sp.
page 10
Physalia physalis
page 9
Muggiaea a lan ica
page 12
Dipleu osoma
ypicum
page 4
Body wi h shape di e en om ypical jelly ish
(siphonopho es and loa ing hyd oid colonies)
Lizzia blondina
Simila species
How does i look?
ou club-shaped en acles
abo e mou h
o en p oducing smalle jelly ish
on he egion a ound he mou h
eigh en acle bulbs on body
ma gin, ou o which may
ca y mo e han one en acle
2 mm
3
Ra hkea oc opunc a a is also small
and has jelly ish buds, bu di e s om L.
blondina in he s uc u e o he mou h
The mou h o R. oc opunc a a has
b anched lips ins ead o he unb anched
club-shaped en acles o L. blondina
Whe e in NE A lan ic wa e s?
Medi e anean Sea o mid-No way
When? summe o au umn
Whe e does i li e? common and some imes abundan in coas al wa e s
Li e cycle: jelly ish p oduced by polyps li ing on he bo om
Whe e does i li e? coas al wa e s, al hough li le in o ma ion is a ailable o his species
Li e cycle: jelly ish p oduced by polyps li ing on he bo om
Simila species
How does i look?
body wi h 5 o18 i egula ly
dis ibu ed canals issuing om he
cen e, o en ca ying bean- o
sausage-shaped gonads
black do s (ocelli) a he base o en acles
5 mm
4
Laodicea also ha e black do s a he
base o en acles, bu unlike D. ypicum
only ha e 4 adial canals
Halopsis ocella a is la ge (up o 150 mm)
and does no ha e ocelli. I has long,
wa y gonads along he egula ly
dis ibu ed adial canals
Dipleu osoma ypicum
gonads on he inne hal o he
adial canals, close o cen e
Whe e does i li e? coas al wa e s, al hough li le in o ma ion is a ailable o his species
Li e cycle: jelly ish p oduced by polyps li ing on he bo om
Whe e in NE A lan ic wa e s? B i ish Isles,
Fa oe-She land Channel, No way
When? sp ing o au umn, mos common
June o Sep embe
Simila species
How does i look?
canals o ming a c oss. On hese canals,
4 sho gonads wi h a g oo e in he
middle. 16 o 32 en acles o he same ype
eliable iden i ica ion o young P.
quad a a om Cly ia species is
only possible h ough DNA
analysis
6 mm
5
Se e al Cly ia species look e y simila , so
accu a e iden i ica ion should be
con i med by an expe
The numbe o s a ocys s (small, bubble-like
o gans on he body edge) di e s be ween
Cly ia species (many) and P. quad a a
(eigh )
Phialella quad a a Whe e in NE A lan ic wa e s?
widesp ead in coas al A lan ic wa e s
When? eco ded all yea , bu mo e
abundan om Ap il o Sep embe
Whe e does i li e? coas al species ypically ound in nea sho e en i onmen s
Li e cycle: jelly ish p oduced by polyps li ing on he bo om
Simila species
How does i look?
la body wi h nume ous sho , igh ly
packed en acles o uni o m leng h
ound gonads along 4 s aigh
canals o ming a c oss
2 mm
6
Young Cly ia jelly ish may look simila , bu
hey a e no la and ha e ewe and
di e en -looking en acles
Solma is sp. has a aguely simila shape
and size bu ha e no isible s uc u es on
he body
Obelia spp.
he jelly ish o he di e en
species o Obelia canno be
dis inguished om one ano he
Whe e in NE A lan ic wa e s?
widely dis ibu ed in all NE A lan ic
When? all yea , wi h peaks in sp ing
h ough au umn.
Whe e does i li e? e y common in coas al wa e s, occasionally o sho e
Li e cycle: me oplank onic, p oduced by polyps li ing on he bo om
Simila species
How does i look?
body simple: la and wi hou isible
canals o gonads
se e al s a ocys s ( iny, o ange
bubble-like o gans) on he body
ma gin
3 mm
7
Obelia jelly ish a e also la and small, bu
hey ha e canals o ming a c oss ac oss
hei body
The p esence o a dis inc mou h and
gonads also dis inguishes Obelia om
Solma is
Solma is sp. Whe e in NE A lan ic wa e s? UK, Fa oe
Islands, mid- o no he n No way
When? insu icien da a, coas ally mo e
common om July o Sep embe
Whe e does i li e? p ima ily in oceanic su ace wa e s; occasionally coas al
Li e cycle: always in wa e column
How does i look?
loa ing colonies wi h ound shape
and cha ac e is ic up igh sail
in ense deep-blue colou and
loa ing on he su ace make i
easy o de ec
7 cm
8
Simila species
Po uguese man o' wa (Physalia
physalis)a e la ge and ha e a gas- illed
loa and longe en acles
Blue bu on (Po pi a po pi a), ound in he
Medi e anean bu no in empe a e NE
A lan ic wa e s, lacks a sail
Velella elella
By- he-wind sailo
Whe e in NE A lan ic wa e s? wes UK
wa e s, e y a ely up o 62° N in No way
When? o sho e yea - ound; coas al
sigh ings peak in sp ing
Whe e does i li e? loa ing on he su ace o he sea, o en blown asho e by winds
Li e cycle: colony li ing a ai -wa e in e ace, loa ing on su ace
How does i look?
colonies wi h a la ge, gas- illed loa
ha s ays abo e he wa e su ace
massi e agg ega ions o en
ollow s ong onsho e winds o
shi ing cu en s
15 cm
9
Simila species
Velella elella has smalle colonies wi h a
sail ins ead o a loa
Physalia physalis is unmis akable in he NE
A lan ic, bu o he , ela ed species occu
elsewhe e in he wo ld
Physalia physalis
Po uguese man o’ wa
long en acles wi h s inging cells hanging
unde he loa
Whe e in NE A lan ic wa e s? opical o
empe a e wa e s, bu no in No way
When? o sho e yea - ound; coas al
sigh ings in sp ing and ea ly summe
Whe e does i li e? loa ing on he su ace o he sea, o en blown asho e by winds
Li e cycle: colony li ing a ai -wa e in e ace, loa ing on su ace
