..4 •

Ir~" ernaiJ J. I' 1".ae_ 1 J.'3. -ion -lf tihe,a

• Bpr~- 1 va in ~ho

Co rd 'e.::rte n 01 the 0. 11 1973 97~

b

Eka Hah beck~.tLS-~·; ., te e .. H a Fisheri

. 0 .... ck, I e1:' DeulO ra ic R cFis

l.nas n ti ain ~hs Abe ..deen

. abWldan

Bank as fchi . t n mber

these 3 year.:: ..

Tne abwlCJanc f at laI' .8

nO.... 'J.u.- es J of the: 0 ey end

1973 - 1975. T e great'st la~

gated were obser e n Ab rinvestiga J. n in 1974 abo "en t

•2. Introauction

Sprat 1 caffi a s bject o~ intensidUIil~ he 1 s ears. pr v

fram a out 20.000 - 30 0to 271 0 0üO . ~! 19?3 and ~7o

int o th

•• •

ae.

t

of'in1 b t

S'

(ANO

A con

~he

•

•

s u ad.cal ulating1 rva

t e east Orkneys.

:-;'P1"'lT: p m r/Oct b r

ragionund ce

i tio fr1 1e tor 1969

t r

v rst 0

'1975

(97 )(94 ati(98 Solo t' na)

ri d ut

e1 in the or~~~wI6S1~eJ~~

I land

h es resulte p r'od fra 1

Abco k pI

- 24.9 1973- 2'1.9. 1974- 30.9. 1975

1

14.920.9.

Siby

d

:f her 'tlli~se

..... t i

he c

1 73

an 1 .. 71larv

4. R. ults

J.nve ti­(n er/m2).

10 mm c

egl ct

than

T e abun dis r~b tiongations :t'rom 1973 - 1975Larvae w't a 1e h u.ntr tion (~ €I nu e can be

rete to sprat larv 1 n e

1973.

larva '/o~ t e

w'''h a lowof th 1 Deth i( ~b

aren b rd an Bank the major~ty 0...ngt of 15 - 21 (maan length on raae

rvae a..... woance wa" in general greater than 4 973,of about 35 larva /m2 a a stat~ n 9n Ab

dist ~bu"on area s ne rly th ameyeaI' e n Bank as t e a e ith the hOg t

:L n.l. hut in 0 par son w:i.th the prev10us y :c e ob6erved~

orth 0 .) e kneys an a omewhat higher~ the Orl" ys.

COL.{~en

19 5

•

here

tion area1e gth

in 1974.it 1973

sprat la"MfAi:r

comp ris n

).

a langth was 1"

f 0,3 mm

ware 13 ~O mm in t

whic h the h~ t c centratjon (meanBank 17,2 mill, i.e. 2.3 mm lass than 1973) •

et B

.Pb ,ra eo•ne catch of a umber jt1lleni e spr. t (3,1,0 - 38,0 mm. hashas 0 ~ne eI~thanLng pie~ s cf t herrin tra 1

5 . h 97' in the area sout of FInde grUDd/Lingbank rete a 0

to a great sprat Jib undance in 19?4

.1222l J) in th~s y. a sp ~ rva in a w r um t

in 1971~. Tnis shows us that t g aa es undance asfaund in 1974 '~thin the ~ ves i ated e iod max. 1975. 2 sI2/station - fig. 5 •

As in prev~ us ye s t e graate t ahunda c 0 ere o· erved 0

Ab erd an Bank.

gre

21

Thi

•5

rreSl;JOli(1

e

me

y •TCl •

Con 5and

our nv .,

t

b

- 5

Ta a 1 Z.~timates of }. eGotal lt'n:. .1'- (x 109 of sprat

larvae '.:'1 the are· illvestJ.fatod in the Nortn Sea

and ad jacent wat"':r i'rom 197.. to 1975:

area nez iod number of ,.10 mmstat'ona.

T ta ~ 13,,9. - 24.9073 97 273Ea~t rlmeys 18.9. - 20.9.73 39 106

bera een Bank 13.9. - 17.9 73 2'+ 99( oU+'h 57·45'.N)NW rkneys 21.9. - 24.9.73 34 68

14.9. - 27.9.74 94 290

East Orkneys 17.9. - 22.9.74 16 101berdeen Banl<: 14.9. - 17.9.74 38 125

rkneys 24.9. - 27.9.74 40 64

.rota1 975 20.9. - 30.9.75 98 227Eas' :)rkneys 23.9. - 26.9.75 28 49Abe aen Bank 20.9. - 23.9.75 26 91mv Orkneys 26.9. 30.9.75 44 ,

87•

F,eferenc .

ANO . 191~

.LDvestJ.gati ns ,on tb b' ...~.di"" ,1"i1: . tion f herrlng larvae inthe l.l.orthe.rn North Sea and ad jacenwaters in 1974leES Co •• 1975, H. 25 (Mimeo)

prat larvae tothe north ofScotlandA1~na-es Biol gig e 29 (1974)pp. 147 - 149

•

•

u0_1 --- L .. J _______ J__

6''''f

5

0•

1 I~

III 5

I,•

o•

o•

•

o..

---~---

o•

,L-- •o•

o•

~-----l----~-----""',

o

o 0•

o

I.•

p ~ l21~L _

s•

:--0..

o

o"

o

13.9.- 24.9.1973

t:is;. 1

Numbers of sprat larva.:?

beneath one square metre "

B 1-9 sprot lorvoe per m 2

•

o

l_-~r, .

0-.0•0 0 0

• • • r-0• •

I •I: D IJ

I ~~-P I-0 00 •0 0• •

--l~;'~ ./'1 t <:> 70.-1 c8~. 1· 0 gO

••' • • I •0 ;jr--i . ~~.3 I

1 0 ~ ~~ . I

:9" 2 _ ..' ßß~ 3 ,0

~•

•--- 0<0::::::::

~.rv 0 ,-O' 0 0 •• • •

0 0G •

ITIIJ 10-49 11 11 11 __L __,-2 l-~------,-sr-- I. 2 0 !6Lo-------TJ-o-----ilro-------TJ-o- 2

Q_ ,0 O_...J

e. '.spraf {arvoe

. flumbers Fig.2 Length distribuUon of sprat larvae 197330

""".

20

70 -

I

10 . 12 14- 16 78 20 22~.. ­1--,

24 26 28 30 32(engfh of sprQ/ (arvae (mm r

--- ---- ---

fotal

south of Fair Isle

() =765

() = 17

northwest of Orkneys () =26

-'-' -.- Aberdeenbon!< n=728

6 (: 5°10 -+-__ ..__---L__

1,0 o 2";

"

[ill] 70-49 iJ 11 I fI

I I --I I I I30'

,6'" ,ft;' 50 31)'

4° ;,0'

0'

•,4

/1

o'"

..o•

o'"

o..

1:l

1- ,

o t)-----r--- .-,-·-~I...L - ---i----'--r---,--_.-.---?" Sf) .... 0 ' I I, .! - 10 On

/----""-==.L- . J

o ,. '0•

• 0•

1- 9 s.o' at larvae per m '2

beneoth one squarG metre,

Fig 3

Numbers "f .:pra t lorvo13

1o -e41

..

(l

.2 0

/r-qL •/ "

./..-•

•

I

[

I ,

,

1210

-,'""/..-.. ....~~':>"'--: ... /-

;, .... ./ :.<,.... ~"." - --.:.: Y / ----... ~- - --:::S;-' .." . ~" ...'I' ,_

I.--...,..---,--r-~-~--r--:lr-· -rr·'---,jr-----.j--".r-""'--::::...,.i~.-rl-..,.,-..,.I --v-........,..-....,.----,-,~,..- .......~r----.'1--.-~~16 18 20 22 24 26 28 30

~

length of sprat larvae (mrn)

20

sprat larvae

numbers Fig.4 Length distribution of sprot larvae ·1974-

30

total

south of Fair {sIe

"northwest of Orkneys

Ab erc!eenbank

n= 194

n =54

n =20

n =420

I . .

.-

2.

o•

o•

. ..Cl•

o

o•

\j

o'"

fl

\,i

e

I1•

.)

•

21

o•G.

•

o•

--- ~ ~-l/-- -----)-- - ~ I!-. o_. ---7"f

i-=..- ro)-~--- ~/' r- _.r-- --.-. ; 0

' - ---r- •L , ---- l .i. . _,

1 1 O.I ••/---L _

//" ------ 7 --J •I 0__. __ . _

1'~- --gI" " (11 -illJh- ?I 1----71 I 1:1

j ,~=I' 11 " _ ... - -=iJ . J~ . 2 6

I t _ •~__ 1 --- • --_I,.--/ .- ._----;.;:,.r·-f

(.. --<L _,-._..- 2"

o•

o..

o•

11 '111

..er mI-t {orlloe pspra ..

oo

c•

g reaterFig. 5 . • larvae •Numbers of spro, lsq metre

th belO\lI .TOmm in lengthan2{j. 30.9.1975

OID 10-49 11

E-3 1-9

(("

rf~

o•

,--,I-_l-~ 21- _-".

t'-~~-! :)~-'~~

/~.- -'-_l_=~ ~O / _.__ \· r-- _~- .. ':.:- - -,-- - .--;~.'-- ----.; -1 ~

•- ----- :'-l ·3-- --I

,... I _ -'- ---- • I1--' • -- ... , _. . .,

I- - ) . II • __ __ • /I _~ .._ )----. -1-/

r-------~ _.:.-, ._ ,_ ~'__II:I • •\-_.- 1--. .._~------.---- - = I.~b-=-=---==-=- _

I. _r .-

sjJrat larva~

numbers . Fig.6 Length ·distribution of sprat (arvae 1975' "'Jot,

24 26 28 ]f) 32length-l Q:t sprat, lar:vaermfn)

222018. 74-12

, ., /l' '. . \

. I'/ .. .\...;... ........../ \/ .-==.~\ .--;. - - - - -?... ... '\.... ... .

_ J ".... / ',\.._.. _......-.-- '- - - -- .... ., .... -','----l----,l'''''·---,--r-.....;;..::::;.:...-.,---r---r---Tj-T-~_·..--,--r----r-----,r---,-----,r--!I'7""':._•. -r-I-~1'--.,--......j _

10

70

20

fotal n =: 187

-------- south 'of Fair 15/@ n= 24

-.......-- north west of Orkneys n= 62~

_._. - ._- Aberdeenbanl< n= 95