Thi;:; paper not to he eitell withilUt, prior l"efprence to the author'
166
C.~:. 19u9/K:lll
International COllncil for
Exploration of thc Sea
Shellfish anl!
Benthos Gommittee
On the Sea:::wnal Distribution of Crang;on Larvae on the
German Coast
by
U. Elss
Institut tür Küstcn- und Binnenfischerei
der Bundesforschungsanstalt für Fischerei, Hamburg
The distribution of larvae of Crnngon crangon during the summer months
durin~ the winter months 19(,R-1969 was
s tudied by means of a IIcnseu-e:~g:-net (diameter 70 cm, I (,lI~t.h '!~() cm).
Thc inv<-sti~ations were car'ried out l1urinf~ .Iuly, SI'[>t.emhpr 1~)6R ;HlII
~Iay 1/)()9 a1l0ar.\ the fisheril's ins[H'ctiou allll rf!search hoat "Nl'ptuu",
Ilurin::,: DeCl'mbcI' 11)(iH ahoarl\ !LV "FricI{rich l1('incl,c", J.11 dlluuary }(.)(ll)
ahoartl FRV "Autou Uohrn" arHI in ~!arcll 191>9 ahonrrl ItV "!-'riedrich Heincl,,'''.
fhe Illnil1 aim of this \Vorl: wns t.o stul1y the Ilistrihut.ion uf Crall!.!:nn
larvne also I{urin/! thc winter IllOnths in con.parison LO thaI.. durinl! the
summer months by uHin~ the same standard net. Thc station maps ~re shown
in Figs. I and ~. ~hile during the summer surveys a regular station net
was covered, which was established in conncction with the routin observations on the larvae distribution along the German coast since 19G3.by
the Institut für Küsten- und Binnenfischerei (Plett, 1965), during the
winter surveys the followin~ sections were covered:
\
I
,
I
1968 and May 1969 as weIl as
, !
!
~
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•
I
a) Fanö Bight - Borkuru Riffgrund - lightvessel EIbe 111
b) lightvessel Elhe I - White Bank
c) :>ignal-fire .\lte WCRer - Borkum itiffg:ruod
d) Büsum - ~hite Bank.
At the selectel! st.at.ions vt'rt..ica\ plankt.on calr.hl'~ wC'r<' malle. Th/' larv:\lof Crao!:,:on crnn'~on \I'ere Hl'paratl'd accnrdin:~ I..n t.tlf·ir' dC'vl'l''1"l1l'nt..al Hta~I'S
followin:~ EhrcllbaulII (IHf.lO). Tlw sin.'.o:If' lilrvOl\ ,,1... ::1'''' \\'/-1'1' count.f~c\ and
lhc 1I11mhl'r of IlIr'va<- 1)1'10\/ I m~ ot' sl1rl"lcl' was cillelllölt.pd.
."
-=-~
The rCRults of ttWht' invc:d.ig:at.ions are cOlnpilcci in l.ahll~s 1 and ~!.
They ::;how that lar~cst larvae cOllcentratioll at.. all was t'olloll off thc
cOllstof North Friesland in July 1968, followcd by thc area r.ov~red by
thc estuaries of EIbe and Weser. ~63 rCHp. 21~ larvae helow I m- were
-countcd. Less larvae ahundance was found at thc eoast of East Friesland.
Already Plett (1965) demonstrated that larvae distribution along the
German coast cnn bc unequally from month to month, and even from year to
year.
I
J
r-,
J
16 7
- .- '1';1
-
bl (' 1
or Crilflgofl l"rv;Lp bplow I m
Fr i \''''' I ;111 d and thC' arca of t.h!' outpr' Clb
~It'all
r'
1\1(1111)(.
nth
0'
orf h· coasl o r
and IV c " I' r.
'0
r t h-
Ol !I
d
1':;1<.; f,-
umber of plankt.on catches
Coast of Ea.tFriesland
90
37
~14
~63
pt. 196
30
97
81
10)
6
196
46
6~
06
05
~y
V
Area of the out r
EIbe and Weser
The lowe·t catcl.1e. of the summerly survey
Cl
)0 larvae nnrlcr l. m- surface.
~rerc
Oll
Coast. o f ,'orthFrie land
an avcrag
not h low
On t.be other hand the average number o f larvae nrnonnted 0 LI 0 t morc tha n
6 durin" t.he surveys made uuring December, Jallua IY and ~:arch 196'2/G(
(tahl ~). IL i . f1otcworthy Lo mention that 1 rvae ci\ught tn Decembcr
and Januar}' were a11 younger tages between I and IV, QO-95 ;C belongint;
r'
to the stages I/lI. Only during Uarch 1969 4 ,v
of t.lle larvae \\'erc of
stages V/VI. a might be mentioned also that thcrc werc le!"s marked dif
ferences in thc horizontal di tribution oI Crangon larvae during the
winter months than are ohviou ly existin,::!: Juring the SUI,me r rnonths.
:
:':
::,
I'"
!',
Table 2
2
Mean number of Crangon larvae below 1 m during tbe wint r wonth", 196 /69
Houte: Fanö-Bight
- Borkum lt.iffgruntl - LilThtvesscl EIbe
umber of plankton
nth
catchcs
~r
12
191>8
Route:
Li~htvcgsel
umbp. r of plankton
1969
11
Route: SL.:,nal-f ire Alte Weser
-
10
L9 l<)
li
Nurnber
JIJIJI)
4,1
I/lI
sta~cH
V/VI
I lI/IV
-
0,5
':J
TI) tal
') , I t
DevelopITientnl
I/II
~
:2,5
I
I
.5
C\cc!"
V/VI
II I/IV
-
(),~
'1'0
Ln 1
~,7
Wbitc Ban){
plallkton
of
calches
flrch
-
Total
Borkum RifI!!:rund
catches
Tl
V/VI
0,2
Devclormental
Li ,
umber of plankton
n h
)l.oute: Diisum
I lI/IV
I/lI
3,9
catches
Iluar
Developmental stac;es
EIbe I - hhite Bank
n h
lluar
III
]
..
llevelonmental
I/II
Tl rLIV
3, I,
1,0
.
<;
Larrcs
V/Vi
(),:.!
1'0 I.a 1
I 1 , (I
- 3 ..;,
168
These results confirm the view expre88ed by several authors (14) that
th~ main spawning time of Crangon crangon is during tbe summer months.
They are contrary to the statement of Boddeke (1966) who says:
"The eggs, attached at the pleopods of the female shrimp,
hatch after two months causing a sharp peak in the
production of 1arvae in January. After tbe hatching of
the eg~s another fertilization takes place, followed
two months Iater in March-April by a second peak in thc
production of shrimp larvae. Smaiier numbers of 1arvae
are found till September."
•
Boddeke (1966) rcfers among others to Rees (1952) who found a sharp
peak in the/production of Inrvae of Crangon crangon in January. When
looking at the data of Rees, however, it has to be considered that
he caught in a 3 years' surveya total of about 150 Crangon larvae only
and that he fished practically outside the main spawning area of this
shrimp. It seems to us that Rees' catches are not representativc for
discribing thc seasonal distribution of larvae of Crangon crangon.
His total cntch was made on the occasion of 65 tows with a plankton recorder over 20 miles each within 3 years and was ~hus smaller than the
best average catches under one m2 made by the Hensen egg net when sieving
a water.co1umn oi lessthan ~O m.'
Our findings are in agreement with Jorgensen (1923), wit.h Thorson (1946),
with Lcbour (1947), with Kühl nnd Mann (1963), with Plett (1965) and
with Dornheim (1969).
I
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:
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!.
SUMMARY
Thc distribution of larvae of Crangon crangon in the Gcrman llight has
been studied at different periods, i.e. summer 1968, winter 1968/69 nnd
May 1969. lt cnn be concluded thnt the peak of larvae abundance is during
the summer, while during the winter months larvae were found to bc very
scarce.
REFERENCES
(1)
Boddeke, R.:
Is it possible to forecast the landings of
brown shrimp ?
ICES, C.M., Shel1fish Committee, M:7 - 1-2,
1966
I
i
I
I
,.; I
I
l
, I
(2)
'(3)
"
"
Dornheim, H.:
Forecastin~ the 1andings of Brown Shrimp
Crangon crangon) in the Netherlanrls.
ICES, C.M. ~hel1fi!'lh and Benthos Committee,
K:8 - 1-2, 1968
On the Biology of Cra"~on crangon (L.)
in the Western Daltic.
ICES, C.M., Shellfish and Renthos
Committee, K:16, 1969
:. Ii
;
j
!
.t I;
tI !l
, 1·1
I,
I;
(4)
Ehrenbaum, H.:
Zur NaturgeHchichte von Crangon vulgaris
Fabr.
Dtsch.Sccfisch.-Verein,Mittl.Spkt.
Küsten- u. Hochseefisch., ::)ondcrb(>ila~e:
9-124, 1890
~
(
\ .
, ;
,
.
,
- 4 -
(5)
Jorgensen, O.M.:
Crustacea. ~ Marine plankton,
plankton investigations.
Rep.Dove Mar.Lab., N.S. 12+11~-33, 192}
(6)
Kühl, H. and H. Mann:
On the distribution of shr.imp larvae
(Crangon crangon L.) in the estuary of
the EIbe,
Veröff.lnst.Küst.Binnenfisch., (27):
50-52, 1963
(7)
Lebour,
( 8)
Meyer-Waarden,P.F.:
( 9)
(10)
(11 )
11
"
Plett, A.:
"
11
(12)
Rees, C.B.:
(13)
Tiews,
(14)
"
Notes on the Inshore Plankton of Plymouth.
Journ.Mar.Bi01.Assoc., XXVI: 527-547,19 117
M.V.
K.:
11
11
Ein Beitrag zur Eiablage der Nordseekrabbe
(Grannt) Crangon vulgaris Fabr.
Zool.Anz., 106 (7/8): 146-56, 1934
Ein Beitrag zur Frage der Laichperiodizität bei der Nordseekrabbe (Granat)
Crangon vulgaris Fabr,
Zool.Anz., 109 (1/2): 23-32, 1935
Furtber results on tbe distribution of
shrimp larvae (Crangon crangon L.)
on the German coast during 1964.
ICES, C.M., Shellfish Committee, 1965
Über das Vorkommen von Garnelenlarven
(Crangon crangon L.) v~r der deutschen
Küste in den Jahren 1963 u. 1964.
Arch.Fisch.Wiss., 16 (1): 54-67, 1965
Continious plankton records: The decapod
larvaein the North Sea, 1947-1949.
Hull Bull.Mar.Ecol., 3 (22): 157-84, 1952
Die biologischen Grundlagen der Büsumer
Garnelenfischerei.
Ber.Dtsch.Wiss.Komm.Meeresforsch., 13
(3): 235-68, 1954.
Synopsis of biological data on the common
shrimp Crangon crangon (Linnaeus, 1758)FAO-Species Synopsis, 1-59, FR:BC SP/67/
SS 1, 1967.
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170
•
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p of larvae catches
rnonths: July 196
•
und May 1969
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