Cleve 1902 Plankton 1900

KONGL. SVENSKA VETENSKAPS-AKADEMIENS HANDLINGAR.

Bandet

35.

N:o

THE PLANKTON
OF

THE NORTH SEA AND THE SKAGEHAK
IN

1900
BY

P. T.

CLEVE

COMMIIXICATED DECEMBER

KEVISED BY

H.I.

TIIEEL

A\D

A,

11,
(i.

lilOl.

NATHORST.

STOCKHOLM
KUXGL. BOKTRVCKKHIET.

I'.

1902

A.

NORSTEDT & SÖNER

7.


D.

'uriiig

inonth,

the

at

1900

ycar

the

Måseskär

west-coast

(or

about

Sweden,

of

were collected ragularly, 3 to 4
58° Lat N.) and Väderöboda (or about 59° Lat

saiuples

of plankton

tiines a

on

N.),

the North Sea, four timcs (February, April, August, No-

in

vember) by stearaers on different routes and, besides, occasionally, by the Governmentsteamer »Svensksund» in the Skagerak and, in July-August, by a tishing boat off the
Shetlands.

The following account contains the results obtained by the microscopical analj^sis
of the samples and has been coinpleted by hydrogi-aphical data, cominunicated by Professor S. O. Pettersson.

January 1900.
Samples were collected
the

steamer

Svenksund

Christiania Fjord).

]\Iost

on

Måseskär

at

(1

sample), at Väderöboda (3 samples) and by

the route Vinga, Marstrand, Lysekil and Dröbak (mouth of

samples were collected from the surface water of the low

nity characterizing the Baltic Current, but at

sali-

Dröbak a sam[)le was hauled from the depth
The two
were vei-y different, and the temperature of

of 30 m. in water of 34 p. m. salinity, so also at 57° 59' N. 11° 14' E. from 90 m.

samples from the water of 34

p.

the water was also different, viz.

m. salinity
7,46

The plankton from Dröbak

at

Dröbak, but

4,45

in the central Skagerak.

had a niore oceanic character, but the plankton from

Skagerak contained about the same species as the Baltic Current at that season, as
be seen from the followinsr

list:

HoUö-Vinga|

IJröbak

Ö7° 59' N.

(Christiania'
fjord)

iri4'E.
Temp.

Calanus finmarchicus
Centropages hamatus

.

.

Microsetella atlantica

.

.

.

.

.

.

.

4,45.

Hollö-Vinga,
Dröbak
fu° 59' N.
(Christiania-

iri4'E.

Temp. 7j

Temp.

Sal. 34,2,

Sal. 34,3.v

Sal. 34,56.

90 m.

30 m.

90 m.

30 m.

Gronyanlax spinifera

Biddulphia aarita

C. decipiens
.

C.

Plectophora arachnoides

C. stellaris

Codonella Tcntricosa

Ceratium longipcs
C.

.

.

.

....

P. divergens

Ditylum Brigthwellii
Rhizosolenia setigera

r

r
.

.

.

.

.

r

.

r

.

Thalassiothrix Francnfeldii

C. tripos
.

,

.

.

rr

radiatns

Thalassiosira gelatinosa

macroceros

Peridiniam depressum

....

diadema

C.

.

.

Coscinodisous polychordus.

Acanthometron pelluciduni
.

I

.

.

....

B. mobilensis

ChEEtoceros debilis

....

7,46.

Sal. 3i,s5.

OncEea minnta

Temora longicornis

fjord).

Temp.

4,45.
i

Oithona similis

Pseudocalanus elougatus

will

Halosphaera

r

+


4

THE PLANKTON OF THE NORTH SEA AND THE SKAGEIiAK.

CLEVE.

T.

P.

The water

of the Baltic Current proved \ery variable as to the salinity.

At

Kalt'-

only reached 6,94, and the plankton at that spöt contained abundantly the euryCopepods Acartia longiremis, Centropages hamattis and Temora longicornis, but besides, some fresh-watei- species, as A sterionella gracillima, 2'(thellar{a flocculosa sund colonies
of a flagellate.
At Marstraiid and »Tslandsbergs Hufvud» the water (15, 80 and 18,37 p. m. s.)
was sterile.
The other saniples from the surface-water of the Baltic Current contaiued
a number of species, the most generally distributed of ^vhicb were:

sund

it

haliiie

Copepoda.

Acartia longiremis
Centropaxjes

n

hamatus

',

,

\

1

,

,

rseudocalanus elongatas

Temora

longicornis

}

boreal, eui'vhahne forms.
•'

I

j

Oithona similis; tenaperate, eurvhaline and eurytherni.

Ciliata.

Ftyclioci/lis acuta.; arctic,

neritic.

Dinoflagellates.

Ceratiiun tripos; temperate, eur\'therm, euryhaline.

Dinopliysis acuta; boreal.
Chlorophyllacese.

Halosp>hcera; temperate.
1

:

1

j;

,,,

•

;.;'(

Diatomacese.

Ti

Chcetoceros horealis; boreal and arctic.

C

danicus; temperate.

C.

debilis; arctic

(.'.

diadoiia; arctic and boreal.

and boreal.

Coscinodiscus concinnus; boreal.
j

Tlialassiothrix Fraucnfeldii;

l:)oreal.

.

.

i

February 1900.
A.

The North Sea was in the tirst da,ys of February explored by steamers on difThe resiilt of the examination of the plankton-samples coUected by these

ferent routes.

steamers bas been registered in Table

1.

''

:

...

-

The plankton in the Ndi-th Sea -was N-er\' scarce in February as a rulc and occurred
any quantity ordy abo^e the edge of the 50-inetre plateau of the Ijottom, chietiy north
of the Dooger Bank.

in


BAND

KONGL. SV. VET. AKADEMIENS HANJJLlNGAli.
rn.

sallnity,

of the Avater of 35

species

teristic

of 35 p.

water

TIk'

p.

N:i)

sal.

•\vere

5

7.

of Scotland, Avas almost sterile.

E.

m.

35.

Most charac-

besides Halonphoera, Acanthonia Miil-

Acaniliometron pellucidum, Plectojyhora arachnoides and Chcetoceros decipiens.

leri,

Other

from that of 34 p. m. sal.
The water of 34 p. m. salinity contained tripos-plankton, and this planktontype was
the ruling kind bet^veen Newcastle and Skagen, and most plentitul uorth of the Dogger
Bank, thus above the limit between the 50- and 100-metre plateaii of the bottom.
species seeiii to have migrated into this kind of water

The bank-water west of Scotland contained abundantly Coscmodiscus concinims and

which were carried with the 35 p. m. water i-ound Scotland towards the
mouth of the Skagerak. The only other characteristic forms which occurred in the bankradiatus,

C.

water Avere Fungella aretica (E. of Scotland) and Tintinnopsis heroidea, Biddulphia aurita

Along the Dutch coast

and Coseinodiccus polychordus (W. of Denmark).
southern neritic plankton occurred.
loped.

In

mouth

from the

place

its

traces merely of

Thus, the typical neritic plankton had not yet deveof the Schelt to the

West

of SchlesAvig appeared

the copepods Teniora longicornis and Pseudoccdanus elongatus, which evidentl}' had spread

from

the depressions of the bottom

The

B.

of

salinit}^

water

contained

soon

horeal

neritic

m.

This

2nd

the

32

things

p.

Skagerali.

between

had,

33

to

S.

Bank and W.

of the Dogger

of the Fisher Bank.

The water at the two stations, where plankton Avas
and 6th of February a teraperature betAvcen 2,i and

p.

sparingly

thus considerably higher thau in January.

m.,

tripos-plankton,

became changed,
and sira-plankton

there

as
in

mixed

A\-ith

appeared

^vater of the

on

JTaloq)ha'ra.,

collected,
3, o

and a

This kind of

but the condition of

the 7th of February at Måseskär

temperature

—

0,35

and the

salinity 22,72

kind of plankton prevailed to the end of the month, both at Måseskär and

at V;\deröboda,

the temperature varying from

—

0,35

to

—

l,o

and the

from

salinity

21,39

and in one sample
only Avere the copepods Acartia longireinis and Temora longicornis found in any amount.
The diatoms Avere, on the contrary, very abundant, and among them the most important
were the folloAvins':
'ö
to

This kind of plankton

26,96.

Avas,

as usually, verv poor in animals

•

'

Biddulphia aurita,

Coscinocliscus polychordiis,

Chcetoceros debilis

Skeletonem.a costatum,

C.

diadem a,

C. socialis,

.

_

Thalassiosira Nordenskiuldii,
Thalassiothrix Frauenfeldii.

March 1900.

'
>

Samples were collected ;it Måseskär and by the steamer »Svensksund» in Kattegatt
Middelgrundet and 56°33'N. r2°16'E.) and at Vinga. The temperature of the Avater
va-ried from 1,2 to 3 and the salinity from 25, 21 to 33,63.
The plankton was everyAvhere
(at

uniform, or sira-plankton, composed chiefly of diatoms.
red

in

skiöldii

Besides the species, Avhich occur-

February (among Avhich Chcetoceros debilis, C diadema and Thalassiosira Nordenwere very common) the folloAving recurred constantly in almost all samples:


b

r.

THE PLANKTON OF THE NORTH SEA AND THE SKAGERAK.

CLEVE.

T.

Rhizosolenia semisjnna,

Chcetoeeros borealis,

B.

contortus,

C.

f
C. teres.

The animals occurred

some few samples

in

only.

The following were noted:

Fritillaria horealis,

Pseudocalanus elongatus,

Caprella septentrionalis,

7'emora longicornis,

Aeartia longiremis,

Cyttarocylis denticulata,

Centropages hamatus,

Ptychocylis acuta,

Tintinnopsis suhacuta.
All these aniraals are boreal or arctic.

At the station Vinga one sample of plankton
where
the

the

Avater

same kind

had the temperature

Avas

collected at the depth of 70

and the salinity

4,9i

34,52.

ni.,

The plankton was of

but very poor.

as in the superficial stratuni,

April 1900.
The North Sea

A.

^vas

explored on several routes by steamers, and the results of

the examination of the samples of plankton have been registered in Table

II.

—

from the hydrographical deterrainations that water with 34 35 p. m.
salinity extends from Scotland towards Skagerak and also E. and S. of the Dogger Bank.
The plankton of this kind of water is totally diflferent from what it was in the
appears

It

Of

winter.

the

insignificant traces only remain.

prevailing tripos-plankton

then

the plankton eonsists chiefly of boreal,

more

Now

or less neritic species, but intermingled with

comparatively rare specimens of a considerable number of southern forms.

The plankton
the

of

34-water, so
water.

every

for

the

order

the

\vater

of

kinds of water,

The

of the
is

bank-water

difficnlt to

determine

to

has a great

number

of species in commoii with

decide what forms characterize the one and other kind
this question

I

noted the

number

had been found in the one and other kind of water.

species

deration
in

In

it

I

relative

lower

number of samples

collected

concluded that

it

Oikopleura dioica,
'

m. and

belonged properly to that kind.

result of this investigation has been set forth in the following

'

p.

salinity, one species was found more frequently in one of these

Boreal or arctic forms

Southern forms

1

with due consi-

in the water of 34

fi-equently recurring forms have been printed with larger types.

-''•'-'

of spöts at whieh

If,

Paracalanus

jparvus,

'

Calanus hyperhoreiis,

''

-'''

Codonella ventricosa,

Phreorystis Pouchetii,

'

Halospkcera,

Ceratium biicephalum,

Gonyaulax spinifera,
Chietoceroti brevis,

''

•'

C.

debi/is,

lists,

in

which


KONGL. SV. VET. AKADKMIENS HANDLINGAR.

BAND. 35.

n:o

C.

lineatum,

Rhizosolenia semispina,

C.

macroceros,

Thalassiosira gravida,

Cerataulina Bergonii

T.

Chcetoceros curvisetus,

Thalassiothrix Frauenfeldi.

C.

densus,

C.

Schiittii,

Nordenskiöldii,

Ditylum Bri'jhtwellii,
Eucampia Zodiacus,
Guinardia jiaccida,

Lauderia annulata,
Rhizosolenia Stolterfothii,

B. styliformis.

Theve
Avest of

can

no

lie

doubt that the southern forras have been transported from the

Scotland and the boreal species from the region of Iceland or the Färöes.

the southern forms

we meet, although

the didymus-plankton of autumn.

It

usually sparingly, a

of specimens

from

the

originated, at least in part,

coasts,

may

towards the continental coasts.
originate,

in

which a number of
If

water,

we

part.

in

facts can

we now carry out

the

west
This

English

doe.s

S.

and

of the Dogger

E.

not disprove that the didymus-plankton

Channel, an opinion

I

lield

previously and for

be adduced.
a similar investigation for the plankton-forms of the bank-

get the folloAving result:
Southern or temperate forms

Boreal and arctic forms

Centropaf/es typicus,

Fritil/aria borealis,

OitJiona similis,

Acartia longiremis.

Evadue Nordmani.

Calanus finmarchicus,

Sagitta hipimctata,

Pseudocalanus elongatus,

Ceratium

frijws,

from the

of Scotland carried towards the Dogger and

Fisher Banks and drifted through the depression of the bottom

Bank

Among

of forms, which form

seems thus that this kind of plankton, or the sum-

mer- and antumn-plankton of the Continental

development

number

Temora

longicornis,

Fl inge ila arctica,
Ptychocylis acuta,

Tintinnus bottnicus,
Pterosp/icera Möbii,

Dinophysis rotun data,

D.

Vanhöffeni,

Peridinium depressum,
P.

ovatum,

P.

pellucidum,

.

Asterionella Japonica,

Jiiddulphia nurita,

,

,

i;


8

T.

P.

THE PLANKTON OF THE NOKTH

CLEVE.

.SEA

AND THE. SKAGEKAK.

Chcetoceros atlanticus,
C.

borealis,

C.

contortus,

C. scolopendra,

Coscinodiscus concinnus,
C. radiatiis,
C-

oculus iridis,

Skeletonenia costatum.

Of

bank-water

few rare specimens only are of southern
It is thus proved that
origin, but the boreal and arctic forms are enormously pre^'alent.
the bank-water at the end of the winter becomes at fii-st populated by arctic and boreal
species,

origin,

found

species

which

the

in

diininish during the sunimer,

or

disappear

a

which arrive in the spring, increase.

Species which occurred as often in the 34

when the

sj^ecies of

southern

m. water as in the bank-water Avere

p.

Acartia Clausii,

Chcetoceros decipiens,

Centropages hamatus,

C. teres,

Paracalanus parvus,

LeptocyJindrus danicus.

Ceratium furca,
C.

fusus,

c.

longipes,

Dinophysis acuta,

Peridinium pallidum.
B.

Måseskär,

The
on

whole

any importance were
B.

setigera,

The plankton was,

Skagerak.
the

Most

poor.

Scotland

perature

The North

58°— 59°
6,7

to 7, c.

N.

judge

Chcetoceros borealis, C. contortus,

l^halassiothrix Frauenfeldii

Sea.
1'

E

—

have

I

2'

W.,

the samples collected at

The only forms

C. decipiens, PJiizosolenia semispina,

three samples only from the Northeast of

collected in water of 35,32 p. m.

sal.

and the tem-

These samples contnined the following species:

OikopÅeura dioica

Oithona similis

Sagitta bipunctata

-\-,

Calanus Jinmarcincns
Centropages hamatus

The plankton was thus

Cyttarocylis dentindata

r,

Ceratium furca

c,

.

-j-,

r,

Chcetoceros decipiens

r,

styli-

-{-,

c,

Pseudocalanus eJongatus

of

1900.

received

all

from

and Divobryum.

May
A.

to

forms had disappeared.

arctic

-f-,

Rhizosolenia styliformis

and tricho-plankton, containing some

c,

neritic forms.


KONGL. SV. VET. AKADEMIENS IIANDLINGA7?.

BAND

35.

n:0

The only samples examined were from Måseskär and VäderöThe Skagerak.
To judge from these samples the formerly prevailing arctic and boreal species had

B.

boda.

Still Ceratiuin lonnipes and Coscinodiscus concinnus are abundant
and more common than formerly. On the other hand a number of southern forms commence to develop, for instance Acartia Clausii, Oithona similis, Evadne Nordmani, Rhizo-

disappeared or died out.

solenia gracillima.

June 1900.
The North Sea. The only samples received that month were 7 collections taken
by a fishing-boat on the 18th to 30th of June near the Shetland Islands, at 60° 20'— 60°40'N.
0° 17'E— 2°45' W., in water of the salinity 35,29 to 35,45 and the temperature 9,8 to 13,2.
The samples contained the foUowing species: ^
A.

Cleodora pyramidata
Acartia Clausii

P ovatum +

c,

+,

Metridia lucens

Oithona jylumifera

P.

+,

decipiens

C.

Loremianus

Ecadiie ^^orchyTiDii +,
Amphorella Norvegica rr,

C. peruvianiis

Coscinodiscus oculus iridis

r,

Cyiiarocylis denticulata

Dactyliosolen antarvticus

rr,

C.
C.
C.

c,

+

furca

Rhizosolenia alata

fasus

r,

R. (jracillima

longipes

R.

c,

fripos

+

list

shows

R.

of

the plankton

that

the

year

r,
r,
r,

c,

+

sti/liforinis

r,
c,

Thalassiosira Nordenskiöldii

r,

Especially interesting

of boreal species.

semispina

R. Shrubsolei

,

Dinophysis acuta

time

r,
r,

c,

'.

t

r,

Guinardia ftacuida
Lauderia annuluia

,

r,

C. macroceros rr,

that

r,

r,

C.

rr,

Cei'atium biicephalum

at

r,

Pseudocalanus elongatus +,

Acantiwmetron cateroatum

This

pellucidum

Dinobryum pellucidum

r,

+,

,

Chaetoceros boreal/s

Oncwa minuta

r,

Peridinium depressum

Calanus finmarchicus

O. similis

Diplopsalis lenticula

c,

r,

is

+.

was a mixture of styli-plankton and a number
the occurrence of Thalassiosira Nordenskiöldii

near the Shetlands.

Cleodora pri/ramidata

is

also of interest.

the distribution of this pteropod is in the north of
According to Boas and Munthe
a line between Buenos Ayres and the Cape of Good Hope to about 50° N., besides, according to Boas, from the mouth of Davis' Strait to the Shetlands. This species thus belongs
'^

'"

to
is

The occurrence of the

desmo-plankton.

the

antarctic species Dactyliosolen antarcticus

also remarkable.

'

Boreal or arctic forms marked by larger types.

-

Acta Havn. (6) IV

3

Bihang

K.

Sv.

till

n.

1

p.

69 1886

K. Sv. Vet. Ak. Handl. Vol. XIII Part. IV n:r 2 p. 17.

Vet Akad. Handl.

Band 35.

N:o

7.


10

The

B.

samples

THE PLANKTON OF THE NORTH SEA AND THE SKAGERAK.

CLEVE.

T.

diatoms were of no importarice.

now

prevailing

type.

Nordmani,

the

Måseskär and Väderöboda.

These
abundantly Ehizosolenia gracillima and Coscinodiscus concinnus; other

contained

tripos-j)lankton

were

Samples

Skagei-ak.

Ceratiuin tripos

Characteristic

was very common and indicates that the

other than these were Oithona similis, Evadne
accompanied by Podo7i Leuckarti. The occurrence of

species

as usually,

hitter,

at

with a kind of southern neritic plankton, N^mct, the

together

was,

collected

Temorella afjinis indicates a strong flow of the Baltic Current.

July— August 1900.
Some samples were collected by a fishing vessel on the 2nd
W. from the depths of 200—50 m., 50—10 m. and the

The Shetlands.

A.

60° 40' N. and 2° 45'

of July

at

surface.

The contents of the
Surface
{t.

3 samples have been i-egistered in the following table:

50-10 m. 200-50 m
(at

12,20
t.

s.

.

.

200

(at

11,80

200-50 m,

m

(at

9,00

t.

t.

35,44)
s.

Calanus finmarchicus

40 m.
35,46)

s.

35,42)

s.

C.

.

longipes

r

Dinophysis acuta

+

D.

O. similis

+

DiplopsaHs lenticula

Oneoea minnta

rr

Peridluium divergens

Microsetella atlantiea

Oithona plumifera

.

.

.

.

.

.

.

Pseudooalanus elongatus

.

.

Salpa sp
Cyttarocylis denticnlata

.

Acanthonia Mulleri

.

Challengoria xipliodon

.

.

.

.

.

.

r

P. ovatuni

.

.

.

.

.

r

rr

.

rr

R. styliformis
Tluilasaiotlirix longissima

c

+
+

from

Atlantic and

this

list

r

Rhizosolenia gracillima

+

.

Nitzschia lincola

r

C. fusus

apparent

rr

Coscinodiscus ocnlus iridis

Dactyliosolen antarcticus

Ceratinm furca

is

.

.

Chsetoceros Lorenziamis

CoUozoum iuerme
Hexalonciie hexac^autlia

.

ocean icum

P.

.

.

homunculus

r

.

Åcanthometron catervatum

It

9,00

35,43)

C. tripos

Metridia Incens

temperate

200 m,

.

+
+

+

.

r
r

.

that the plankton (styli-plankton) originated in the

The occurrence of
the Shetlands marks the extreme

contained only few and rare northern forms.

Dinophysis liom.unculus and of ChaHoceros Lorenziamis at
northern limit for these species.

The North Sea in Jvily-Angust. The North Sea was explored at the end of July
and the beginning of August by a number of steainers on difterent routes. The results
of the analysis of the numerous samples of plankton collected have been registered in
B.

Table

^:

III.

The determinations of the
are

represented.

If the species

salinity

found

prove that

all

.!-:.-

''
;

'<-^--

'

•

l^-'"-!

kinds of water, from 35 to 24,62,

in the plankton be classified according to the sali-


KONGL. SV. VET. AKADEMIENS HANDLINGAR.
nity,
to

or

it

will be

found that inost species occur

BAND

35.

11

K:0 7.

in all kinds of water.

Still,

have tried

I

make out whether some species eould not be considered as occuring chiefly in the one
other kind.
The result Avas the following:
The 35 p. 111. water contained exclusively or prevalently the following forms:
Isias clavipes (doubtless neritic),

Podon Leuckartii (doubtless
These

species

are

neritic).

be considered as occasional intruders in a kind of Avater, to

to

which they do not belong properly.

The 34

p.

m. ivafer:

Acartia longiremis (boreal, neritic),

Labidocera Wollastoni (meridional,
Codonella ventricosa

neritic),

meridional and boreal),

(neritic,

Ceratium longipes (boreal),

Dinophysis Vanliöffeni (boreal,

arctic),

Gonyaulax spinifera (boreal),
Peridinium ovatum (arctic and boreal),
Peridinium palliduni (arctic and boreal),
Rhizosolenia Stolterfothii (meridional, neritic).

The forms derive thus
Water

of 32,49

to

from the north and in part from the south.

in part

33,95

p.

m.

salinity contained as

most characteristic the

follo-

wing forms.

Temorn

longicornis (boreal, neritic),

Sagitta liipunctata (meridional),

Amphorella subulata

(neritic,

meridional and boreal),

Noc.tiluca miliaris (meridional, neritic),

;

.

V

'..

i

.•

.

-

..

.

Ceratium bucephalam (meridional),

Peridinium globulus (meridional, oceanic),
P. oceanicum (meridional, oceanic),

Guinardia jiaccida (meridional,

neritic),

Leptocylindrus danicus (meridional, boreal, neritic),
Rhizosolenia calcar ovis (meridional),

R. Shrubsolei (meridional),

,

R. styliformis (meridional, oceanic).

Most species characteristic for
of

oceanic,

origin.

This

indicates

this

,

kind of bank-water are thus of southern, in part

that they have been swept

from the southern Conti-

nental coasts by a flow of Atlantic water containing styli-plankton.
Atlantic

species

Rhizosolenia

styliformis

,

As

the characteristic

occurred abundantly along the dutch coast and

from there sparingly to the Limfjord, it
been driven through the Euglish Channel.

is

evident, that water with styli-plankton had


12

v.

THE PLANKTON OF THE NORTH SEA AND THE SKAGERAK.

CLEVE.

T.

Water of 24,6o

to

32,05 p. m. salinity contained as characteristic forras:

Froto peclata (meridional,

iieritic),

Cyttarocylis denticuhtta (oceanic, boreal

and

arctic),

Tintinnopsis campanula (meridional, neritic),
T. jistularis (neritic, meridional),

Noctiluca miliaris

(in

common

with the

kind of water),

last

Bellerochea malleus (neritic, meridional),

Rhizosolenia gracillima (oceanic and neritic, euryhaline, meridional).

Almost

these forms are thus of southern origin.

all

Most coininon or generally distributed in

of water ivere the folloioing:

all kinds

Oikopleura dioica (meridional, neritic),
Acartia Clausii (meridional, oceanic),

Anomalocera Patersonii (meridional,

neritic),

Ca/anus finmarchicus (boreal and arctic, oceanic),
Centropages hamatus (boreal, neritic, euryhaline),
C.

typicus (meridional, oceanic),

Oithona similis (meridional, oceanic, euryhaline, eurytherm),

Paracalanus parvus (meridional, oceanic),

Evadne Nordmani (temperate or boreal, oceanic, euryhaline),
E.

spinifera (meridional, oceanic),

Podon intermedius (meridional,

neritic),

Sagitta bipunctata (meridional, neritic

and oceanic),

Anvphorella Steenstrupii (meridional, oceanic),

Ceratium furca (meridional, oceanic),

'

of

macroceros (meridional, oceanic),

C.

tripos (meridional, oceanic),

Peridinium, divergens (meridional, oceanic).

'

all

C.

The common species are printed with larger types in the above list. Most coinmon
were Ceratium macroceros and C. tripos, and as they occurred in all kinds of water,

the plankton of the whole North Sea at this time of the year
plankton.

southern

It

is

origin,

apparent from the

last list that the

The

were taken

Skagerak,

at the

be classified as tripos-

bulk of this kind of plankton

a comparatively small amont only originating in boreal regions.

had thus since April been a complete change of water

C.

may

in

July.

The

in

of

the whole North Sea.

only samples collected in June in

two stations Mäseskär and Vaderöl>oda.

is

There

tlie

Skagerak

The teraperature of the water

varied at these staticms from 13, o to 18, so and the salinity from 18,7o to 32,92.

in
Ije

The plankton was partly tripos-plankton and the variety of southern neritic-plankton,
which Rhizosolenia gracillima predominates (Nma). If the plankton at both stations
compared,

a

slight

difference

is

apparent.

At

the

more southern

station. Måseskär,


BAND

KONGL. SV. VET. AKADEMIENS HANDLINGAR.

35.

13

N:0 7.

thus appeared suddenly and abundantly Rliizosolenia sti/lifonnis and some other southern

not found or occurring only sparingly at Väderöboda, as Rliizosolenia Shruhsolei,

forms,

Guinardia flaccida, Chcetoceros Schuttii, Evadne spinifera; at Väderöboda on the contrary
the northern Pseudoca lantis elongatus and inore abundantly than at Måseskäi* tlie southern
Acartia

This

punctata.

Current

Oithonn

Clnusii,

goes

is

most

straight

parvus, Evadne

Nordmani, Sagitta biassuming
by
that the water of the Jutland
the station Måseskär, and that the water froin the Norwegian
Paracalantts

similis,

satisfactorily explained

to

depression appears sooner at the northern station \'äderöboda than at Måseskär.

The Skagerak in August. The saniples taken at the two
Väderöboda had a terapei'ature varying between 16,3 and 19, 20.
D.

between

26,84

and

stations Måseskär and

The

salinity

varied

20,79.

The prevailing plankton was

both stations tripos-plankton, but at Måseskär inter-

at

mingled with didynius-plankton, as in the

last

month.

Besides, there appeared at Måse-

Evadne Nordmani, Paracalanus parvus, Sagitta bipunctata etc,
July at Väderöboda and not at all or sparingly at Måseskär.
skär

wliich ocurred in

September 1900.
only.
29,98

The Skagerak. Saniples of plankton were
The teniperature of the water varied from

Mäseskär and Väderöboda

collected

at

16, o to

13, 20

and the salinity between

and 22, le.

At both stations the prevailing plankton was tripos-plankton, that had remained
from the last month, but at the niore southern station Måseskär this kind of plankton
was more or less abundantly interraingled with didymus-plankton, charaterized by ChaHoceros contortus, C. curvisetus, C. Schilttii and Skeletonema costatum, no doubt brought by
the Jutland Current.
The total nuraber of planktonforms noted during September
',
amounted to 37.
:-:i;.
;> :.;. -r-;
•.

•.

October 1900.
The Skagerak.
in

water,

the

were collected at the stations Måseskär and Väderöboda
of which varied from 12,65 to 9.95 and the salinity between

Samples

teniperature

The plankton collected at both stations was, on the whole, very similar
and consisted of trijjos- and didy mus-plankton intei-mingied. The latter kind was more
27,38

and 31, 09.

predominant at the southern station. Måseskär.
The number of species collected at these stations was large and had increased considerably since the last month.
The prevailing
It now amounted to 84 different forms.
forms of the didymus-plankton were the following:
...
,:,•,.
.

Chcetoceros contortus,

Eucampia

.

C. curvisetus,
C.

debilis,

C.

didymns,

C. Schilttii.

'

-

'

.

',
.

'.

r

zodiacus,

Guinardia flaccida,
RMzosolenia Stolte rfotJdi,

-

'

,.

Skeletonema costatmn.


14

P.

The
certain

T.

CLEVE, THE PLANKTON OK THE NOETH SEA AND THE SKAGERAK.
consists

(i«(i_y//u
number

chiefly

of

southern neritic forms, but contains a

of northern forms as Chcetoceros debilis, Skeletonema costatum

cannot, on the other hand, be any doubt that this kind of plankton

Skagerak with the Jutland Current and from the southern North Sea.

a. o.

There

brought into the

is

Therefore

it

seems

necessary to admit, that the northern forms have migrated from the northern part of the

North Sea and, through the submarine channels S. and E. of the Dogger Bank, penetrated
towards the Continental coasts. These submarine channels really seem to exercise a
very great influence on the distribution of the plankton above the 50-metre plateau of
the bottom and also on the migration of the fishes.

November
A.
steamers

The North
crossing

In

Sea.

that

month

1900.

a large coUection of samples were taken

by

The microscopical examination

the North Sea in different directions.

of the plankton proves that the prevailing types were tripos- and c??V/y?>nformer kind occurred chiefly between 58°— 59° N. 0= E. and 55°— 56° N. 1° E., most
abundantly between 55° and 57° N., and especially W. of the Danish Peninsula. The

North Sea, from Holland to Skagen, where it
became intermingled with triposplankton.
The plankton was collected in all kinds of water, containing 35 to 28 p. m. salinity.
I tried, as in the former cases, to make out what species characterize the one or

other kind and with the following result:
Water of 35 p. in. salinity contained Acanthometron catervatum and Chwtoceros
atlanticus, which may be considered as characteristic, as other forms also occurred in
didyinus-\>\?inkion prevailed in the southern

'

the 34

p.

ra.

salinity.

That also was the
of 34 p. m. salinity contained chiefly tripos-plankton.
water,
both
having
common
in
a number of
case with some samples from the 33 p. m.
Water

species of almost equal frequency in both kinds.

Common

water were the following forms:

to both kinds of

Forms

of southern origin.

Centropagus typicus +
Oithona plumifera rr,
O. similis

Metridia lucens

+

rr,

Pseudocalaniis elongatus

+

2'><^i-rvus

Sagitta hipunctata

+

Codonella ventricosa
Dictyooysta elegans

c,

c,

longicornis

Tintinnus acuminatus,

Dinophysis acuta

+

r,

r.

r,

r,

,

Gonyaulaa: spinifera

rr,

Peridinium pallidum

r,

P. piellucidum

Xanthidium

c,

c,

Cyttarocylis denticulata
r,

rr,

Dictyocha Jibula r,
Distephanus speculum
Ceratium furoa

Temora

,

Anvpliorella Steenstrupi

C. fusus

of nortliern origin.

Calanus finmarchicus

,

+

Paracalanus

Forms

rr,

hystrix rr,

Asterionella japonica rr,

C. macroceros cg,

Chcetoceros decipiens

C. tripos cc.

Coscinodiscus radiatus

r,
r.


KONGL.

Peridinium divergens +
Pyropliacus horologium

Chcetoceros Schuttii

Roperia

the

evidently

35.

N:0

7.

15

,

r,

r,

tessellata rr.

The in^os- plankton contained
forms,

BAND

VET. AKADEMIENS HANDLINGAK.

SV.

former far

raoi-e

prevalent in

number

and noi^thern

This kind of plankton

of individuals.

of Scotland by the fusion of water from the temperate eastern

N.

originates

thus, as usually, a mixture of southern

Atlantic with water from Iceland, the Färöes and the Shetlands.

As

m. water,

Forms

more frequently than

for the 34 p. m. water or occurring there

characteristic

in the 33 p.

consider the foUowing forms:

I

Forms

of southern origin.

Acartia Clausii

of northern origin.

Spirialis retroversa

r,

Lahidocera WoUastotiii

Acartia longireniis

rr,

Evadne spinifera r,
Podon intermedius rr,

r,
r.

Centropages hamatus

Acanthochiasma fusiforme
Acanthonia Mälleri r,
Halospliwra viridis +
Ceratium buoephalum c,
Peridinium Michaelis

r,

Ceratium longipes

rr,

Hensen

yiSternhaarstatobla.sfy

+

Peridinium depressuin
Pterosphwra Möhii rr,

+

Kanthidiutn multispinosuni

—

Water of 33 28 p. ra. salinity contained, besides such forms
quently in the 34 p. m. water, the following species:
Forms

Forms

of southern origin.

Oikopleura dioica

Fritillaria borealis rr,

r,

+

Plectophora arachnoides

Euterpe acutifrons

r,

Binophysis Vanhöffenii

Peridinium ovatum r,

(^Amphorella suhulata

Codonella Jörgenseni

rr),

campanula

Ceratium lineatuni

Chwtoceros borealis

+ ),

r,

var. Briglitwellii rr,

C. constrieius rr,

r,

rr,

Diplopsalis lenticula

+

Peridinium peduricidatum
Prorocentrum, micans

r,

Bacteriastrum, varians

r,

Bellerocliea mallens rr.

Biddnlphia mobilensis
Cerataulina Bergonii

r,

C.

debilis

C.

diadem a

C.

laciniosus

c.

r,
r,

(C. excentricus

+ ),

Rhizosolenia setigera
c,

r,

+

Cpscinodiscus concinnus

Skeletonema costatum,

r,

rr,

Thalassiosira gelatinosa

r,

(Clicctoceros contortus c),

T. gravida rr.

C. curviseius

Thalassiothrix Frauenfeldii

C. densus
C.

+

didymus

r),

Phaiocystis Pouahetii rr,

r,

+

Noctiluca miliaris

rr,

rr,

(JCantliidium brachiolatum

rr,

{Tintinnopsis beroidea

T.

as occurred as fre-

of northern origin.

Corycceus anglicus

Cyttarocylis serrata

r.

rr.

c,
,

c,

Ditylurn Briglilwellii

c,

•

;

r.

16

T.

P.

CLEVE, THE PLANKTON OF THE NORTH SEA AND THE SKAGERAK.

Eucampia zodiacus

c,

Guinardia flaccida c,
Lauderia annulata rr,
Lithodesiniwn undulatum

+

R. ffraciUima

M. Shrubsolei

r.

+

R. Stolterfothii
R. styliformis

,

c,

Stephanopi/wis turris

The

names

of

rr,

+

Rhizosolenia calcar aris

species,

aboiit

c.

which

it

is

at present uncertaiu whether thcy are soiithcni or northern,

have been cnclosed iu brackets.

The

prevailing

of Southern origin.

number

Among

of species belong to the r/'/c/?/?u?
these forms there occurred abundantly in the southern North

Sea the diatom Rhizosolenia styliformis, Avhich

temperate Atlantic.

an oceanic species of the
the Continental coast had been

in niy opinion

is

That proves that the bank-Avater

off

niixed with Atlantic water, entering through the English Channel.

The Skagerak at Vinga. The Government steamer »Svensksund» collected on
November at Vinga two samples of plankton, one from the surface and one
The surface water had the temperature 6,02 and the salinity
at the depth of 30 m.
and
belonged
thus
to
the Baltic Current.
The water at 30 m. was warmer (tem21,01
perature 9,5) and had the salinity 32,75.
The latter kind must thus be classified as bankmicroscopical
examination
water.
The
of the plankton proved that the Baltic Current
The water of the Baltic Current
contained tripos-, but the bank-water c/{t/?/»i«,.s-p]ankton.
derived consequently in part from the Baltic and fresh water from the coast and in pai't
from tlie North Sea, above the 100 ra. plateau of the bottom. The bank-water on the
contrar)', originated from the southern North Sea, above the 50-metre plateau of the
B.

the '21th of

bottom.

C.

The Skagerak

at

Samples collected

Måseskär and Väderö.

at the stations

Måse-

skär and Väderöboda were taken in water of the temperature 8,3 to 5,9 and of the salinity 20,61 to 28,82.
rich

in

forms,

not

The plankton was, on both
less

than

73

different

places, essentially of the

species

same kind, very

belongiiig partly to the trijjos- and

partly to southern and northern neritic plankton, the two latter constituting together
I

Avliat

have called didyniusplankton.

December

1900.

Väderöboda
in Avater of the temperature 6,0 to 3, o and the salinity 21,33 to 30,94. The plankton was
less abundant than in November but rich in species, 78 different forms having been noted.
The plankton belonged to tripos- and c/u/y/xn.s-plankton, as in the preceding month, but
the relative abundance of the species seemed to have been somewhat altered.

The Skagerak.

Samples

were

collected

at

the stations Måseskär and


BAND

KONGL. SV. VET. AKADEMIENS HANDLINGAR.

35.

17

n:o

report on tlie plankton of the
North Sea in 1899.

Additional notes to

Siiice

my

plankton

»The

paper

tlie

of

the North Sea, the English Channel nnd the

was pnblished I received a series of 5 samples, collected in December
1899 on the route Göteborg Hamburg. The results of the microscopical analysis have

Skagerak

in

1899»

^

—

been registered in the following

list:

December
48' 57' -7'

Latitude N-

10° 36'

Longitiide E.

Temperatnre

4

,

O

j

I

9° 25'

i

13th

and 14th 1899.
N

57" 4'

55° 4'

55' 7'

Latitude

8° 25'

7° 34'

7=51'

Longitude

7,25

5,0

4,5

5,0

34.3.3

.32,(i2

32,0-1

57° 48' 57°

E

jlO°.g6';

Temperatnre

I

9°

4.0

7,25

31,00

34,79

I

Salinitx-

31,

no

;

34,79

.i

r

Cliffitoceros brevis

Corycffius anglicns

r

C. contortus

Oithona similis

.

C.

.

.

.

.

C. debilis
C. decipiens

.

Amphorella Steenstrupii

rr

\

Tintinnopsis l)croidea.

....

C.

laciniosns

C.

similis

C.

teres

C.

polychordns

r

C.

radiatus

furca

+

C. stellaris

C. fiisns

r

Ditylum Brightwcllii

r

Eacampia zodiacus

r

Gainardia flaccida

.

Ceratinm bucephiilnm.

C.

lineatnm

C. longipes
C.

macroeeros

....

+

C. tripos

Dinophysia aeuta

.

Diplopsalis lentieula

Gonyaulax spinifera
Peridinium Michaelis

.

r

.

.

.

.

.

....

+

Lauderia annulata

+

c

Leptocylindrus danicus

rr

r

Rliizosolenia calear avis

.

.

c

r

ne

+

rr

n

+

.

.

r

.

R. gracillinia

.

R. setigera

.

R. Shrubsolei

.

ovatum

rr

P. pallidum

R. styliformis

rr

Pyrophacas horologium

Skeletoncma costatum

Pterospliaera Moebii

Stephanopyxis turris

PhEeocystis Poucheti

Tlialassiosira gelatinosa

Asterionella japonica

T.

Biddulphia aurita

Thalassiotlirix Frauonfeldii

B. mobilensis

.

Plankton-type

K. Svenska Vet. Akad. Haudl.

K. S». Vet. Akail.

lliuidl.

Biind 35.

Volume XXXIV.
N;o

7.

.

.

.

.

.

gravida

...

Cerataalina Bergonii
^

5.0

33,ot

.

R. Stolterfntbii

P.

4,5
32,i;2

excentrions

C.

C.

5,0

34,33

....

Coscinodiscns confinnus

Tintinnus a<'uminatns
.

!

7'

C. didymiis

.

Cyttarocylis deuticTilata

Halosphsera viridis

7° 51'

carvisetus

Sagitta bipnnctata

T. canipanala

55°

7° 34'

C. danicns

Pseadocalanus elong.atus

Codonella ventricosa

,55° 4'

'

Salinitv

Calanus finmarchicus

Metridia Incens

4'

8" 2,5'

57

:i7'

2.5'

i\:0

2.

rr

+
r

+

....-, Nm
1900.

Tp

Tv

Km

(Tp)
{Nrii.)

Tp

Nm


18

P.

CLEVE, THE PLANKTON OF THE NORTH SEA ANt) THE SKAGERAK.

T.

how

two first saraples are, although they had
The first sainple consists of didywusplaiikton, or of forms from the southern North Sea, and the second of ^rzpo.s-plankton or
from the northern North Sea. ViOih. are comparatively richer than the following three,
which eome from a raixture of water from the southern and northern North Sea.
It

of interest to note

is

different the

been collected at a distance of about one degree.

Seasonal distribution of the Plankton-organisms.
Appeiidiculaiia.

and V.

sula to Sk.

M.

r.

-f-.

Jutland.

M.

V +.

June:
c.

V.

Vinga (30

M.

r.

m.),

March: M. rr.
November: Sk. rr.

r.

Oikopleura dioica Fol.
Scotland

—

Lohm.

Fritillaria boroalis

—

W.

r;

of the Danish Penin-

between Dogger Bank and Sk.

Ajjril:

r.

May:

N. E. of

Dogger Bank; W. of
October: M. and V. +.
November: M. r,

Jidy, August: Scotland to Sk. v; S. of

r.

+,

September: M.

W.

April: Sk.

•

V.

of Jutland, Sk.

r.

December: V.

r.

rr.

Pteropoda.

— June: Shetlands
— November: W. om

Cleodora pyraniidata Lin.

ce.

Spirialis retroversa Fi.em.

Limfjord,

Vinga (30

r.

ra.)

r.

Amphipoda.

—

Aniathilla aug-ulosa Rathke.

November: V.

—

Caprella septentrionalis Kröyer.

—

tjord

December: V.

r.

r.

Fehruary and March

Parathemisto oblivia Kröyer.

Proto pedata Leach.

Marek: V.

cc.

Fehruary: Mouth of Scheldt

.u,

-|-.

,

:

.

r.

rr.

July

— Aui/ust:

W.

of Lira-

'
'

.

,

,

Cladocera.
Evadno Nordmani Lovén.
Shetlands

-|-'

Norwuy; M.
''-

I

use

r,

tlio

^^-

V.

'-'cc^

c.

V-

ccc.

—

September: M.

:i))l)r('via1ioii

M.

l'nr

April:

Jtdy

W.

— August:

c,

V.

-)-.

of Jutland

Orkneys

May: M.

V.

Jime:
and Firth of Tay to southern
r.

October: M.

r.

Novemher: M. and V.

r.

Måseskär, V. tor Vädt^röboda and Sk.

cc,

for

Skagoii.

r.


KONGL. 8V. VET. AKADEMIENS HANDLINC4AK.

—

Evartue spinifera P. E. Mull.
central North Sea v; M.

-f->

^-

July

—

Lilljeb.

M.

Sei:>tember :

~\~-

W.

sparingly in the central North Sea and
Podoii intennedius

— August:

BANU

from the Dutch coast
V.

-|-,

October: V.

-|-.

P. polyphemoides Leuck.

to Skagurak;

}•.

November:

of Jutland.

July

— Au(/ust:

— June: M.
— July: M.

V.

c,

Uoggcr Baiik

Nortli of Scotland to

(max.) and the Skagerak, as a rule not common; V. -\-. September: M.
November: sparingly from 57° N. 4° E. to Sk.
December: V. rr.
P. Leuckartii G. O. Särs.

19

N:0 5.

35.

July

r.

— August:

October: V.

r.

rr.

57° N. 1° E.

c.

Copepoda.
Acartia Clansii Giesbk.
to Sk.; at about 58° N. 3° E.

Shetlands

the

c,

M.

-\-,

V.

—

January: central Skagerak

February: from Holland

rr.

April: from Holland to Sk. -f. May: M. c, V.
July August: from the Orkneys to Skagerak,

—

c.

Dogger Bank; M. r, V. -)-. Sejitember: M. c, V. /. October: M. and V.
sparingly W. and E. of Scotland and thence to Jutland; M. rr.
of

A.

M.

bruary:
V.

M.

r,

January: as a rule common in the Baltic Current.
FeApril: Skagerak, more or less common.
May: M. -\-,
July August: N. and E. of Scotland, S. W. of Norway;

Marek: M.
and V. r.
September: M. +, V. r.
October: V.
Norway. December: M. and V. r.

Jmu:
V. +.

c.

—

longireniis Lill.jeb.
-(-.

1° E. to S.

-|-.

M.

—

November: from about 57° N.

rr.

—

r

r.

June:
and E.
November:
c.

S.

Auomalocera Patersonii Templ.
January: M. rr. June: M. rr.
N. of Scotland, off the Dutch coast and between Jutland and Norway.
Calanus flnmarchicus Gunn.

—

January: Dröbak (oO

Tay to Dogger Bank and Skagen, as a
common. May: N. E. of Scotland, V. -(-.

rule

/•.

V.

m.),

July

— August:
.

•

February: Firth of

r.

April: N. and W. of Jutland rare to

June: the Shetlands

c,

M.

r.

July

— August:

more or less common; N. of the Dogger
Bank; S. of the depression of the bottom south of Dogger Bank; M. r, V. r. Septeruber:
M. r, V. c.
October: M. rr, V. r -\~.
November: not rare round Scotland and thence to
Norway and Jutland; S. E. of the Dogger Bank. December: M. rr, V. -\- r.
the Shetlands r; N. of Scotland to the Skagerak,

Calanus liyperboreus Kröyer.

— April: W.
— January:

of Limfjord rr (surface!).

Centropages hamatus Lill.jeb.
as a rule common in the Baltic Current.
r.
Marek: rare at 56° 33' N. 12° 16'E.; M. +. April: E. of the depression

February: M.
of

the

bottom

S.

of Dogger Bank, off the Dutch coast; N. of

N. E. of Scotland; M.
Scotland,

Firth

the Dogger

Bank

of

c,

V.

Tay and

rr;

c.

June: M.

-|-,

V.

the Skagerak; M.

M. and Vinga

-|-.

c.

r,

July
V.

r.

Denmark; V.

— August:

October: M.

December: M. and V.

-}~-

-|-.

common between
c.

May:
north

November: N. of


20

CLKVK, THE 1'LANKTON OF THE NORTH SEA

T.

P.

—

AND THE SKAGEKAK.

January: central Skagernk rr. February: rare at 55° N. 6°
7°E.; M. r.
April: N. of Jutland r.
July Aagust: common from N. Scotlaiid to
S&pteiiiber : M. and V. -fOctoher:
S. Noi'\vay, rare from Holland to Sk.; M. -|-, V. r.
V. -\- r.
M.
November: more or less common round Scotland and thence to S. N(jrway
and W. Jutland; M. and V. r. December: M. r.
Kröyek.

typiciis

0.

—

—

6',

Corycfeii8

—

Lubb.

angliciis

February:

July— August: rare from Holland to Sk.;
of Jutland moi-e or less

from

at 58° N.

common; M. and V.

tlie

N.

4° E.

Vinga (30

rr,

of the

Dogger Bank to Skr.
November: W.

Oclober: M.
rn.).

—

November: from the coast of Holland
most common W. of Schleswig; M. and V. r. December: V. rr.
Enterpe acutifrous Dana.

clavipes

Isias

M.

+,

V.

—

Boeck.

July

— Aiu/ust:
—

Metridia lucens Boeck {M. hibemlca

— 50

February: W. of Sk.

Microsetella

of

to

58° N. 8°E. rare.
similis

Dutch coast

r;

the

in

lands

-\-,

M.

Sk.
v..,,

.'.

i

.

V.

V.

+•

—

January: Dröbak (oO

— 10

m.).

February:

metres).

—

January: central Skagerak rr. February: from the
and July the Shetlands. November: at 57° N. 4° E. and
.

rr,

r;

r.

-|-.

c,

c.

S.
c.

inimita Giesbh.
r.

Dogger Bank to the Scheldt; the Shetlands; M. and
October: M. r, V r -j~- November: round Scotland, thence
Vinga -|-, M. c, V. -|-v. December: M. and V. -f-.

of the

—

Jauuary: Dröbak (oO m. «)• February: E. of the Firth
June: the Shetlands rr. .July: the Shetlands (200—50 m. rr).

—

April: very rare north of Jutland.

veuibrr:

of Scotland, central North Sea and

VV.

otf

Paracalanus parvus Claus.
north

— January: central Skagerak

—
July August: the Slietlands (200

/.

of Forth rr; 58° N. 3° E.

common

Robts.

c^

,:•-,.,

Norway and W. Jutland.
Oiicaea

the

November:

— January: not rare in the Baltic Current. February: the
— 58° N. 0° E. to Sk. M. V. April: very rare at some
V.
Sea; V.
May: N.E. of Scotland; M.
June: the Shet—
July August: common from the north of Scotland to Dogger

Bank and the Skagerak, also
V c. September: M. and V.
to S.

the Dutch Coast.

Brady & Robts).

November:

Claus.
from 56°

North
c,

Jv.ne

r.

ofi'

rr.

Bkady

Baihd.

pluinifera

Oitliona

spöts

September:

rr.

July: the Shetlands (200

above the Fisher Bank.

Dogger Bank

Norway.

December: V.
atlautica

— August:

June: the Shetlands -|—

r.

S.W.

and

metres)

S.W. of Norway.

O.

-)-.

r.

July
Labidocera WoUastonii Lubb.
from about 56°— 57° N. 4°— 5° E. to Sk.; V.

rr.

the Dutch coast; M.

ofl'

to the Limfiord,

February: rare

July

— August:

of Scotland to the central North Sea.

along the Swedish west coast.

September :

oft"

the Dutch coast and

W.

of Jutland.

not rare from Holland to Sk. and from
In

July not

cc at

rare,

M. and V.

but in August very
October: M.

c.

No-

not rare round Scotland and thence to the west of Jutland and Skagerak; M.

December: M.

r

-f

r,


KONGL. SV. VET. AKAUEMIENy HANDLISGAK.

('urrent

Bank,

thence

to

January:

the Dutch coast and to Denuiark.

Ilarch: M.

W.

south of the Dogger Bank and the Dutch coast and
the

Skagerak, not rare.

the

Swedish

S.

W.

c,

Temora
S^vedish

area

V.

June: rather rare along

-|-.

— 50

N. of Dogger Bank,

rnetres),

to tlie

February:

N.

c.

May: M.

and Skagen, M. r.
between Scotland,

—

January: common in the Baltic Current along
50-metre ])lateau of the bottom of the North
Mardi: M. r. April: common from 56° N. 4° E. to 55° N.

longicornis O. F. Mull.
coast.

Sea to the Dutch coast; M.
7° E.

t;,

the Shetlands (200

April: between the

-|-.

of the Danish peuinsula, not rare;

V. -|—

Jutland, also

the

M.

N.E. of Scotland;

— AuguM:

in the Baltic

Dutch coast. Sk., M. and V. rather common. Septemher : M. rr.
November: not rare roiind Scotland and thence to S. Norway and
N. of Holland, not rare along the Swedish coast.
December: V. -j- r.

Bank

of Dogger

October: M.

May:

July

coast.

common

or less

iriore

21

n:o 7.

Februari/: the northern slope of the Dogger

west coMSt of Sweden.

the

aloiig'

—

Boeck.

elongatus

Pseiidocalaims

HAN D 35.

55° N.

of the

c,

6° E.

V.

Temorella

affinis

V.

— Autjust:

rare in the

M. and V.

September:

July

rr.

at

common between
M. rather common

Noveinber:

?•,

M. rather common, V. not

Jane:

and Skagen, rather rare

V. r -{-.
M. and V.
October: M.
way and W. Jutland; Vinga r (not rare

r at

-|-.

30 m.),

at

Scotland,

V.

;

-|-.

S.

Nor-

December:

rare.

Poppe.

—

January: Lysekil

rr.

June: M.

-|-.

V^.

r,

Cliaitognatii.
Sagitta

East of Scotland to Skagen,
of

Scotland

the Skagerak,
tober:

V. -f

M.
r.

r,

-|-;

V.

;.

—

& Gaim.
January: W. not

common in some spöts. April: N.

Quoi

bipuuctata

July — August:

N.E.

February: from the

rare.

of Jutland

of Scotland and from the

where not rare along the Swedish coast. Sep)teniber:
+. November: from the N. of Holland and 57° N.

r at

rr,

+

V.

May:

N.E.

Dogger Bank to
M. and V.
Oe-

1° E. to Sk.,

V.

December: M.

r.

M. and

/.

Cteiiopliora.
Plcurobracliia

i»ilciis

Fabr.

—

Ja;naary: V.

r.

SeiJtember: M.

Ciliata.

— June: the Shetlands
Lachm. — July — August: rare

Aiuphorella norvegica v. Dad.
A, Steeustrupii Clap.

&

M.
Dogger
;r
Bank and Sk. October:
Octo
North Sea and N. of Jutland.
A. subulata Ehb.

Holland,

W.

—

1

July

rr.

—August:

November: rare

W.

1 ) 1 <

I

;

/

1

rr.

.- )'

rr

from

tiie

E.

E. of Scotland,

of Jutland and at M.

of Jutland, Sk., V. and M. always sparingly.

:

December: M.

/.

rr.

of Scotland to
in

the central

November: N. of


22

v.

CLEVK, THE PLANKTON OF THE NOHTH «EA AND THK SKAGERAK.

T.

Jörgensenii

Codonellii

N.

Cl.

—

Sp.

November:

very

Holland and

of

N.

rare

Skagen.

at

House

Descr.:
wall

as long

This

short,

diameter of the opening

0, 01,

its

nearly as Ijroad as the

Length and breadth of house

house, with soiue few rings.

length of the proboscis

broad, with a short ai)ical spiiie;

as

Proboscis

malleate.

indistiiictly

0, 05

mm.;

mm.

0,044

reminds one of Codonella orthoceroK Möbius (non

species

the Fifth Ber. der Commission zu Kiel (1887,

Hkl.)

in

Avhich

form Brandt has proposed the name Tintinnopsis baltica, but
to me to represent a young specimen of Tintinnua Jiatu-

33), for

fig.

which seems
Codonclla Jörgensenii

450

same

the latter probably the

MöB.,

^^''"'*
Cl..

as

&

Tintinnus helix Clap.

LaCHM.

m.

t.

—

& Lachm.

January: Dröbak (30 metres). Febr uary:
of Scotland and of Jutland.
Jdly August:
April: r. E. of Firth of Tay.
W. of Jutland. October: M and V. rr. November: common W. and N. of Scotland,
thence to the W. of Jutland and the Sk.; ;it Dogger Bank; oö' the Dutch coast; Vinga
December: M. r, V. r.
(30 m. +), M. r, V. r.
Clap.

(Tintiunopsis) veutricosa

c.

W

Cyttarocylis deuticulata Ehb.

W.

—

.

—

January: M.

Febr uary: from E. Scotland to the

r.

Mardi: M. rr. May: not rare N.E. of Scotland and at M. June: the
more or less common. July August: the Shetlands, Skagerak and Måseskär;
not common.
November: N. of Scotland, the central North Sea, Sk. as a rule rare, Vinga
r (30 m. +); M. and V.
r.
December: M. rr, V. r.
of Jutland.

—

Shetlands

+

Cyttarocylis

Dutch coast and

serrata

in the Skagerak.

Dictyocysta elegans Ehb.

|,,.,

Fuugella arctica Cl.

—

Möb.

—

July

—August:

October: M.

—

c

of the Firth of Tay; r

E.

November: N. of Jutland

rr.

November: N. of Scotland

Febniary: Firth of Forth

oft'

the

December: V.

r.

r.

April: at Skagen

r.

—

r.

r.

Brandt.
January: M. c, Vinga
V. r.
February: W. of Sk.
March: M. rr. April: from the depression of the bottom E. of Dogger Bank
to W. Jutland and Skagen; Skagerak not rare.
May: M. r. November: rare at 57° N.
4°E. December: M. and V. rr.
Ptycliocylls acuta

M.

rr\

Tintiunopsis beroidea Stein.

W.

February:

i

":

T. caiupanula Ehb.

M. and V.
of Holland,
T.

r.

—

January: central Skagerak, M. and GuUmaretjord

November: common

of Jutland.

and N. of Jutland.
'

/',

r.

—

i-- '>'':'

June: V.

'^'

r.

.a,
July

the

oft'

tistularis

Möb. {Tintinnus

— August:

sparingly; V.
helix Clap.

more or

coast,

less rare

W.

-

v.

September: M. and V. not common.

W. and N. of Jutland,

Dutch

r.

&

Mouth

October: M.

of the Scheldt, Skagerak,
r,

V.

rr.

November: N.

r.

Lachm.?)

in the Skagerak and less rare along the Swedish west coast.

—

July

— August:

September: M.

r.

sparingly

October: M.

rr.

BAND

KONG. SV. VET. AKADEMIENS HANDLINGAR.
Tintinnns acuminatus Clap.
r

W.

of Sk.

November:

r

S.W. of Norway.

—

T. bottiiifus NoRDQUiST.

April: Sk.

—

Hensen.

»Steriiliaarstatoblast»

— January:

& Lachm.

central Noi-th 8ea

December: M.

Mny: M.

r.

23

N:0 7.

35.

r,

r.

Fehruary:

rr.

V.

r.

November: N. of Scotland

r.

Cystoflagellata.

—

Noctilnca miliaris Surir.

V.

November:

rr.

W.

r

Jnly

— Aiu/nst:

of .Tutland; M.

very cominon W. of .Tutland.

Oetober:

rr.

Silicoflagellata.
Dictyoclia fibula Ehr.

W. and

—

Oetober:

V.

November: rare N. of the Dogger Rank,

rr.

N. of Jutland.

Disteplianus speculnm Eiib.

from Hollnnd

to Sk., Vinga,

—

November: W. of Scotland,
December: M. and V. rr.

Oetober: M. and V.

M. everywhere

rare.

rr.

Radiolaria.
Acantliofrliiasma

—

Hkl.

fusiforme

Februari:

.57°

N.

6°

W.

r.

November:

ronnd

Scotland.

Acauthoinetrou
the

September:

Shetlands.

— 59°N.
A.

V.

—

Hkl. {A. qundrifolium).

catervatiini

Oetober: V.

r.

Jxini'

and Jidy: not rare

at

November: rare east of Scotland, 58°

rr.

0°E.
pelliicidum

J.

—

Mull.

January: Dröbak

February: rare in the

rr (30 m.).

northern North Sea.

Acanthonia
Shetlands (200

Miilleri

— öO

m.).

—

Hkl.
February: comraon N. of the Dogger Bank.
November: N. of Scotland r.

Challengeria xiphodon Hkl.
Collozoiim inerme J. Mull.

Hexalonche hexacaiitlia

J.

Plectophora arachnoides

—
—

July: rare at the Shetlands (200
.Tuly: Shetlands

—

Mull.

— 50

.Tuly: Shetlands

& Lachm.

Clap.

(200

—

(200

— öO

July: the

ra.).
,

'

ra.)

r.

— 50

in.)

rr.

January: central North

Sea,

Dröbak

in.)
and V. always rare. February: not rare above the limits between the 50- and
Novem,ber: S. of Norway r, Vinga r.
100-metre plateau of the bottom, V. r.

(30

,

Cliloropliyllacea*.
Halosplispra

Sweden,

rare

to

viridis

Schmitz.

comraon,

Dröbak

—
r

January:
(30

ni.).

Skagerak to the west coast of
Februnry: ronnd Scotland to Sk., raost
central


24

CLEVE, THE PLANKTON OF THE NORTH SEA AND THE SKAGERAK.

T.

P.

abundant at 58° N.
V. rr.
November:
cember: M. -)-, V.

7°— 3°E.;

i-ound

M.

W. of Jutland
mouth of the Skagenik; M. and

April: E. of Skagen and

r.

to the

Scotlaiid

rr.

V.

Octoher:
rr.

De-

r.

Dinofl.ngellatfP.
buccphaliini

Ceratinin

—

(-l.

January: M.

February: W. of Scotland; more or

r.

from Newcastle to Sk.; M. r. April: N. of the Dogger Bank. June: the Shet.July
August: N. of Scotland r, S.W. of Norway r. September: M. aiid
lands, not rare.
November: from E. Scotland to S. Norway and Juthmd, inost
V. r.
October: V. rr.
W.
Limfjord.
Vinga (30 m.) r. December: M. rr, V. -)- r.
abundant
of
less rare

—

—

DuJ.

C. fiirca

central Skagerak

January:

Scotland and Newcastle to Sk., V.
of Scotland

and Sk.

NeAVcastle

W. and

N.

M. and V.

Scotla.nd

rule

a,

—

+,

V-,

+

V.

to S.

-(-.

the Shetlands

October:

July — August:

r.

May:

N.E.

between Scotland,
rr.

of Jutland

November:

(maximum);

r.

r,

V.

r.

February:

mouth of the Scheldt and

the

sparingly W. of the Danish Peninsnla.

April:

e,

M. and V.

Norway and W.

central North Sea

January:

area betAveen Newcastle,

;

sparingly.

c.

September:

r.

December: M.
Du.T.

July — August:

from Newcastle

Scotland,

of
r.

fusus

C.

as

April: from the Dogger Bank to Sk.

r.

.June: the Shetlands

;.

February: W. of Scotland, from

r.

the Shetlands (200

E. of

Norway, everywhere

S.

May:

W. and

V.

.June: the Shet-

v.

—

10 m.), M. r, V. r.
September: M. r,
November: sparingly roiind Scotland, thence to the Dogger
Bank (where common), sparingly from Holland to Sk.; Vinga (30 m.) r, V. rr.
Decouber: M. rr, V. -\-rr.
lands

V.

?;

V.

r.

October: M. and V.

r.

fl.

— April:

lineatum Ehb.

of Jutland

V.

r,

rr.

rr

off'

the Dutch coast.

December: M, and V.

rr.

October: V.

rr.

November: N.

r.

—

January: central Skagerak to M. and V., as a rule rare. FeApril: not rare from .56° N. 0° E. to
Marc.h: M. rr.
bruary: central North Sea r; V. r.
May: M. cc, V. cC. longipes

lands

M.

cc,

Bail.

V.

r,

July— August:

r.

the Shetlands

(200—50

m.);

E. of the Firth

of

Bank and Fisher Bank r. October: M. and V. -f-. November: W. of
Scotland; N. of the Dogger Bank to Sk.; coast of Holland to Sk. everywhere rare, Vinga
December: M. and V. c.
(30 m.) not rare; M. and V. r-\-.

Tay

-|-;

C.

bruary:

June:

Dogger

as

the

C.

M.

e,

V.

c.

Tripos;

Shetlands

common) and

Sk.

—

Mmi.

inacroceros

r;

M.

January:

r.

Jipril:

V. not rare.

(^vhere

not

rare);

September: M. and V.

Scotland and between Scotland and
of Jutland; Vinga

+

(30 m.); M.

c.

S.
rr,

and at Vinga. Feand S.W. of Norwa}'.

rare in the central Skagerak

very rare in some spöts

July

— August:

S.

N. of Scotland to

sparingly from the mouth of

tlie

Norway (where
Scheldt to Sk.;

October: M. and V. c.
November: sparingly W. of
Norway, common N. of the Dogger Bank and W.
V.
December: M. a,nd V. r +.
r.

+


KONGL. SV. VET. AKADEMIENS HANDLINGAR.

—

tripos NiTzscH.

C.

Newcastle

from

56°

rare;

M.

— 57° N.

January: whole Skagerak, rare

N. of the Dogger Bank),- M. r to

Sk. (max.

to

West coast of Jutland,

4° E. to the

June: the Shetlands, more or

rr.

BAND
to

common. Fehruary: from
r.
May: M. rr. April:

V.

c,

as a rule rare; the

common; M. and

less

25

N:0 7.

35.

V.

cc.

Skagerak

July

ver)'

— August:

Shetlands c and common in the whole North Sea, from Scotland to S. Norway and
from the Scheldt to Sk.; M. and V. c. September: M. and V. cc. October: M. and V. cc.
November: round Scotland r; from the N. of the Dogger Bank to Skagerak c; Vinga cc;
M. and V. cc. December: M. and V. cc.
the

Diiiophysis
c.

Kattegatt'

April:

r.

r;

Shetlands

M.

Sk. r:

January: central Skagerak r; west coast of Sweden r,
from 58°— 59° N. 0° 30' E. to S. Norway; M. rr. March:
rare from 56° N. 3° E. and 55° N. 6° E. to Sk.
May: M. r.

February:

Gullmarsfjord

June: the

—

Ebb.

acuta

not
r,

M.

July

r.

October: M.

r.

rr.

Holland, Sk. and S. Norway; V.

—

D. Iiomunculiis Stein.

r.

— August:

the Shetlands (50

and

Sk.;

V.

D.

July: the Shetlands (200

rr.

of Jutland

m.)

April: N. of Jutland

—

Jörgensen).

Cl.,

— 10

January: Lysekil

r.

5° E,; M.

the

—

W.

m.); E. of Newcastle;

Gronysiulax spiaifera Clap.

June: the Shetlands

of Jutland; M.

&

Lachm.

V.

r.

r.

rr.

November:

r.

July

October: M.

r.

— August: the Shetlands

rr.

November: sparingly

Vinga (30 m.)

Sk.;

October: V.

r;

V.

rr.

—

January: Dröbak (30 m.) r. April: between

E. of Newcastle and W. of Jutland r.
of the Dogger Bank and N. of Jutland.
Decem-

July — August:

Firth of Tay, Holland and Skagen.
October:

May: M.

—

from the coast of Holland and from the Dogger Bank to

ber: V.

r.

D. acunnnatn and D. norvegica Clap. &
July August:
Ain-il: W. of Jutland r.

N.W. end of tho Dogger Bank and at 56°— 57° N.
November: N.W. of Jutland r; V. r. December: V. rr.
at

rr.

November: rare in some spöts between Holland

r.

Ostf. {D. granulata

Diplopsalis lenticiila Bergh.

(50

M.

-)-,

—

— 50

1° E.,

rr.

Vanhöitenii

Lachm.
rare

W.

m.); E. of Scotland

November: sparingly in the area between 56° N.
December: M. and V. rr.

D. rotimdata Stein. (D. Michaelis AuEiv.)

July — August:

— 10

N.

rare

r.

Peridiniiim

depressum

—

Boil.

.Jnnnary:

central

Skagerak

r,

Dröbak (30 m.)

r.

April: area
in some spöts above the 100-raetre plateau of the North Sea.
57° N. 3° E., Sk. and 56° N. 7° E., most common N.W. of Jutland; sparingly ofif

February: rare

between

the Dutch coast; Skagerak

r,

— August: rather

M.

r.

V.

and

W.

Jutland; Vinga (30 m.) rr ; V.

July

M.

rr.

Peridinium
58° N. 3°E. and

W.

V.

rr,

May: M. and V.

c.

common W. of
November: W. of Scotland

M.

divergens Ehb.

W\

of Jutland to S.

r.

—

Band 35.

N:o

7.

r; area

December: M.

between 56° N.
rr;

V.

-|-

1° E.,

S.

r;

October:

Norway and

r.

January: Dröbak (30 m. r). Febnmry: very rare at
May: V. c. July—Au.gust: N. of the Dogger Bank;

of Sk.; M. rr.
Norway, Skagerak

K. Sv. Vet. Akad. Handl.

June: the Shetlands

-j-.

Scotland; rare off the Dutch coast.

r;

The Shetlands (50

— 10

m.); M. and V.

Sep-

r.

4


26

T.

P.

M.

tember:

-|-,

not rare; V.

V.

r.

55°— 56°

—

—

named

first

E.

spöt

—^August:

Norway

W. and N. of Jutland r.
Vinga (30 m.) rr; V. rr.
July

rai^e.

— August:

Dogger Bank and the Dutch
July

rare.

October: M.

November: N. of

(200—50

the Shetlands

rr.

April: from 57° N. 4° E. to Sk.

to the

of the Firth of Tay.

r,

December: V.

June: the Shetlands, not

Peninsula.

Vinga (30 m.)

November: N. of

rare above the Fislier Bank.

May: M. not

—

P. ovatum PoucHET.

the

July

Vanh.
W. of Jutland; M. r.

r,

— August:

the southern

P. oceanicuni

m.)

or less sparingl)' N. of
Jiitland;

rr.

July

—

Ehb.

W. of

Scotland rr;

November: more
Norway and W. of

r.

r.

Michaélis

P.

V.

-|-,

1° E. -to S.

N.

December: V.

P. g-lobulus Stein.

Scotland rr; Sk.

M.

Octoher:

r.

from

and

Scotland

THE PLANKTON OF THK NORTH SEA AND THE SKAGERAK.

CLEVE.

—August:

common, hut sparingly from

coast; rare

W.

the Shetlands

r,

of the Danish
rather

common

November: rare N. of Scotland and N. of Jut-

r.

land; Vinga (30 m.) rr.

—

February: 57° N. 6° E.

rr.
March: M. r. April: sparingly
and the W. of Schleswig; M. rr. May: M. r. June: V. r.
November:
July August: E. of Firth of Tay; M. r. September: M. r.
October: M. r.
W. and N. of Scotland; from Holland to Skagen, always rare.

P.

Ostf.

palliduni

from the Firth of Tay

—

to Sk.

—

P. pedunculatum Schutt.

57° N.

November:

sparingl}'

from Holland

to Sk.

and

at 56°

4°— 5°E.

—

at 58° N.

7° E.

and
March: from 56°33'N. 12° 16' E. to Måseskär r. April: from 57° N. 4° E.
to Sk. r; Skagerak and M. r.
November: very
June: the Shetlands r.
October: M. rr.

rare at 57° N. 1°— 2° E. and N. of Jutland; Skagerak r.
V.
rr.
December:
pellucidum

P.

Bergh.

January: M.

February: very rare

r.

'

59° N. 1°E.

Protoceratium reticulatuni {Peridinium

non P. reticidatum Schutt)
Pyropliacus

W.

August:

—

horologiura

May: M.

of Jutland

sparingly from S.W.

Prorocentnim

M.

-|->

Norway

& Lachm.

Protoc.

aceros

February:

at

58° N. 3° and 10° E.

r.

October: M. and V. rr.
Dogger Bank; rare N. of Holland.

September: M.

r.

to the N- of

micans Stein.

—

Bergh,

rr.

—

Stein.

Clap.

ret.

October: V.

rr.

rr.

July

—

November:

November: N. of Scotland and N.

of Jutland.
"

'

.'
'

'

'.'

';

Pterosplifera

ary:
r.

rare

in

Möbii Jörgens.

Cystae.

(Pterosperma M. Ostenf.)

—

January: M.

the area between 58° N. 3° E., 56° N. 4° E. and Sk.; M.

April: from the Dogger Bank to Sk. r; V.

rr.

May: M.

r,

V.

r.

r.

Febru-

March: Vinga
June: M. r. July

rr.