Ihis paper not to be cited wjthout prjor reference to the Council.
INTERNATIONAL COUNCIL FOR
TUE EXPLORATION OF TUE SEA
C.M. 1988/0:27
Demersal Fish Committee
REPORT OF TUE MEETING OF TUE COORDINATORS IN
TUE STOMACH SAMPLING PROJECT 1985 TO 1987
IJMUIDEN, 28 MARCH - 1 APRIL 1988
- - -
1
1
INTERNATIONAL COUNCIL FOR
TUE EXPLORATION OF TUE SEA
C.M. 1988/G:27
Demersal Fish Commiuee
REPORT OF THE MEETING OF THE COORDINATORS IN THE
STOMACH SAMPLING PROJECT 1985 TO 1987
IJmuiden, 28 march - 1 april 1988
1. TERMS OF REFERENCE.
ICES passed during its 75th Statutory Meeting in Santander aresolution (C.
res. 1987/2:10) that:
The species coordinators involved in the Stormich Sampling Programme
in the North Sea will meet from 28 March - 1 April 1988 in /Jmuiden to:
a) evaluate the results obtained thus far with a view to providing
input for the Multispecies Assessment Working Group;
_b) organise the exchange of stomach content data and define
requirements for setting up an international data base.
2. PARTICIPATION.
The following people' partieipated in _the meeting:
Dr. P.J.Bromley
Dr. N.Daan (Chairman)
Mr. H.Gislason
Dr. J.R.G.Hislop
Mr. S.Mehl
(UK, England)
(Netherlands)
(Denmark)
(UK, Scotland)
(Norway)
3. INTRODUCTION.
I
t'.
I
l
FolIowing a rceommendation in 1984 (lCES C.Res. 1984/4:12), a new sampling
programme for eod and whiting was started in 1985 with a view. to eolIeeting data
which would allow a validation of the assumption underlying MSVPA that
suitability of prey as food for predators is coristant over time. During aperiod of
three years (1985 to 1987) stomachs were to be sampled at a eomparable level of
intensity as in 1981, but for logistic -reasons sampling was to be restricted to the
first and third quarter only.
'
.
Cod and whitirig were selected, because it was proven that these could be
sampled adequately during routine surveys carried out during the agreed seasons.
It was realized, however,. that more extensive information was also required to
evaluate thc impact of saithe on various other exploited species imd it -was deeided
to eolIect as many sampIes .as possible for this species as weil.
In view of ihe forthcoming meeting. of the Multispecies Assessment Working
Group, thc data obtained so far. were to be analysed so as to provide thc neeessary
'input to, this meeting. Since the evahiation of the results is more appropriately
dealt wilh in association with MSVPA~ this aspect was largely delayed until a laler
~tage.
2
The methods used correspond hirgely to the ones applied to the 1981 data.
However, strindariiation was greatly enhanced by a close, cooperatic)n between the
institutes in Aberdeen and IJmuiden in setting up a common data base and using
the same computer programs.
,
'
During a former meeting of the Multispecies AsscssmentWorking Group, the
wish has been expressed to split the information on sandecls irit<> a northerly and
a ,southerly stock component in accordance with the assessments of the Industrial
Working Group. Although this could be done in principle and would not be
difficult for the new data sets, it was at this stage not feasible to do so for the
complete data set collected in 1981, because not all- data ,were available for
computer processing. Since a partial split would create logistic difficulties in
running a MSVPA~ it was decided to work up the sandeel data for the time being as
if they represent one stock.
.
4. NE'V DEVELOPMENTS IN MSVPA~
,
_
..
, The MSVPA progrnm has now been changed so that it can use a time series of
food composition data to estimate an average suitability. Thc procedure was
described by Gislason and Sparre (1987) and is illustrated in Fig.1. ,
.
An initial guess at the quarterly suitabilities is used to estimate predation
mortalities and stock sizes. In each quarter for which food composition data are
available these stock sizes are used to estimate ci new suitability matrix in the usual
way. The guessed suitabilities are then replaccd by a weighted average of the new
suitabilities and a new set of stock sizes and mortalities estimated. The procedure is
repeated i.mtil the average suitability remains fairly constant;
The weight givcn to each suitability estimate should in some way reflect the
precision with which the food composition is determined; With all the
complications introduced by regurgitated stomachs, by weighting the sampIes
with ,the abundance of the predator, by prey and predator, ALKs etc. it is very
complicated to derive a statistically sound estimate of the reliability of each
individual set of data on food composition. At present the idea is therCCore to use an
estimate of the number of full stomachs sampled from each predator age group to
,.
weight the individual estimates of suitability.
However, an additional complication remains. In the MSVPA the food
compositiori of each predator age elass is estimated from:
,
r.,
Food Comp
G . N . W -stom
= --~-----­
LG. N. W-stoin
prey
I>;
l·
\
la
\
I'
Where .G is suitability. N is the average numbers, of a particular prey age
group and. W-stom is the average iridividual weight of the prey age group at
ingestion. Assuming suitability to be coristant. the average numbers of each prey
age group can be estimated. by the MSVPA; provided estiinates of W-stom are
'available; In years and quarters with food composition' data such estimates exist.
but, in the remaining time span W-stom musteither. be calculated from an
additional model of size selection 01', it must be assumed to remain constaill with
time. The present' version of the .MSVPA model uses .the second, and more simple
option. Given several years of data on food compositon arid W-stom' for a particular
quarter the program initia11Y.,calculates a, weighted average of W-stom where the
weight given to each observation equals the number of prey items observed. This
quarterly average is then used in a11 subsequent calculations.
.
5. RESULTS.
Thc tables' preseiited for the three' species correspond hirgely to' the lay-out.
used for the iables to bc included in the Cooperative Research. Report on the 1981
'
3
Stornach SampÜng project.. They inclüde numbers per stomaehs sampled per size
class, area and quarter, foo'd composition by mäjor taxa by agc class, quarter for
the total North Sea and the average stomaeh content weights per 1000 fish by age
cl ass of commereially exploited prcy specics by predator age class, quarter and
year for the total North Sea. The latter represent tables represent the input
required fOf MSVPA.
. .
.
In .addition a mean prey weight at age by prey age class was calculated for
eaeh predator agc ehiss by quarter over thc full range of years over which data
have been colleeted, ineluding 1981. These are also used as input for MSVPA (see
also seetion 4). For eod and whiting these tables were derived by dividing the total
weights by the total numbers of prey after summing over the years. For saithe the
average prey weights in each quarter will be calCulated dynamieally during
MSVPA program execution. Thereforc, the data presented here refer to thc newly
colleeted data set specifically.
5.1. Cod.
,
Thc cod sampIes collected in 1985, 1986 and 1987 have all been analysed arid
the .complete set of data was. available for further analysis.Thc total number of
stomachs sampled per quarter varied between 2500 and 3800 (Table 1.1.1/3), so that
the level of sampling intensity is comparable to the 1981 programme. There were
no major, gaps in areas sampled in any of thc seasons. Food composition by major
taxa is given in Tables 1.2.1/6 and MSVPA input data in Tables 1.3.1/6. Mean prey
weights are given in Table 1.4.1/2
5.2.'Vhiting
Whiiing stomaehs were sampled in the first and third quarters of. each year.
All the 1985 sampIes have been analyscd and the. data processed, using the suite of
programs developed at IJmuiden. Only part (ca 25 %) of the 1986 sampies have
been analysed and processed. As all the 1986 whiting data presented in this report
relate to sampIes collected from the northem arid central parts of the North Sea
(Table , 2.1.1/2), they must be regarded as highly provisional. Food eomposition is
given in Tables 2.2.1/4 and MSVPA input data in Tables 2.3.1/4. Mean prey weights
are given in Table 2.4.1/2
5.3~
l
SaHhe.
No stomach sainples were avaiIablc from 1985 and 1986 quarter 1. In 1986
third quarter 258 sampies ,containing a total of 2104 stomaehs were eollected by
England, The Netherlands, NOrWay and Scotland (see Table 3.1). Among these~ 1227
were classified as full, 247 as empty arid 630 as regurgitated. Compared with 1981,
when only 1338 stomaehs were collected over the, entire year, this is a most
satisfying result. SampIes are also available from 1987, quarters 1 and 3. These
sampIes have all been analysed, but have not yet been processed.
,
Stornach contem composition is given in Table 3.1, MSVPA iriput data in Table
3.2 and inean prey weights in Table 3.3.
5.4. Prey ALK's.
.
The age composition of the, fish prey can only be accurately estimated if
suitable prey ALKs are available. In most eases saiisfaetoly keys were. obtained, rOf
each area, year and sampling period . from the IYFS arid vafious national surveys.
However, there is still a problem ,with sprats and sandeeIs.
"
In the ease of sprats, area. ALKs for the first quarter were 'obtained from thc
1985, '1986' and 1987 IYFS. No ALKs could be found for the third quarter of any of
these years, so, it was necessiuy to process the data by, applying the 1981 thii-d
quarter ALK (Table 4.1) 10 aB areas. This is obviously
very unsatisfaciory'
solutiQn.
"
..'
.'
"
'."
The, situation' is not inuch better for, sandcels. Thc Industrial Fish WO.was
rather critieal of the keys used in the 1981 SSP, and suggested that area ALKS
a
4
would have bcen more appropriate, or at the vcry lcast a distinction should have
becn .made bctwccn the northcm and southern piuts of the. North Sea. In the
present exercisc, 'northein' and 'southem' ALKs were obtained from the Danish
iridustrial fishery. Thc 'northem' kcy was appIicd to sampling areas I, 2 and 3 and
thc 'southem' key to the remaining iueas. However, it must be admitted that these
ALKs are far from ideal rind for lack of better data, in some .instances area rind
quarter, specific ALKs had to. be used from other years as indicated in Table 4.2.
. The group recommends, that the Industrial Working Group look into this
problem rind strongly, urges interested parties to provide 'better sprat and sandeel
ALKs so that the quality of the output data can bc enhanced.
6. FOOD CONSUMPTION.
6.L
,
,.
Digestion, experiments.
Peter Bromley reporied on the gastric evacuation experiments
on cod,
whiting and turbot which have been undertaken at Lowestoft.. By the nature of the
design. of gastric experiments a bias is introduced' into the results as the
percentage of fish with empty stomachs increases with time towards the end of. an
experiment. Since stornach content cannot fall below zero the variance of the
stornach content is therefore censored at zero. The effect of this is to give the
impressiori that gastric evacuation slows down at low levels of stomach fullness. ,
For whitirig. a curved relationship observed between meari weight of
stornach coritent plotted against time was consistent with, and could be predicted
from, a linear evaeuation model in .whieh evacurition rate in gh-1 was constant
and independent of meal size, time after feeding and the level of stornach conterit.
In the ease of 268g whiting fed meal sizes ranging from 1.9 to 9% of body weight at
10 0 C, the evacuation rate averaged 0.31 gh- 1 for sandeeIs. (This does not of course
exelude the possibility that ,evaeuation rate might deelirie somewhat when very
small meals are corisumed and the rate will also vary with size of predator and
teniperaturc).
Such findings considerably alter the view of how stoinaeh content data from
the field siuripling programme should bc used to caleulate the fecding rate
estimates to be used as input to MSVPA. Up to now it has been assumed that the
gastrie evaeuation rate is proportional to the. level of stomaeh fuIIness. Assuming
that ,the evacuation ratc for fish of a particular size is constant, regardless of the
level of stoniach fuIIness, the average evacuation rate of the population is
dependent on the proportion of fish whieh have food in the stornach and the
proportion which are empty. (or which contain indigestible remains), sinee the
.
latter will have a zero evacuation rate (Bromley, 1987).
Preliminary comparisons show that feeding rates ealculated in this fashion
are roughly. two or, three times higher than thc feeding rate estimates curreritly
mied as input data, for MSVPA. However, the results of the Lowestoft experiments
give estimates of the maximal feeding rates which are likely to be observed, since
the experimental temperature was towards the upper. range of those normally
encountered by cod arid whiting in the North Sea; After correetiori for
teniperature and with more, precise information on the proportion of, fish
containing only traces of food or indigestable remains,. the discrepancy between.
the two estimates will be rcduced. An appraisal of the fceding rate data used in the
1986 MSVPA (Bromley, 1986) indicatcd that the. resulting food conversion
efficiencies were withiri physiologieally acceptable levels: The effect of
increasing the feeding rate estiniate' is of course to reduce eonversion efficiency.
Resulting conversiori efficicncies are still" physiologically "acceptabh~ but whether
theY. give better or worse estimaies of food convcrsion efficiency betwcen trophie
' ,'. :
',
'
levels, remains uncertain.·.
Thc gross bioehemical composition of the fish prcy would also. appear. 10 be
an important, factor governing evacuation rate. In wel weight terms,. cad
evacuated small sandeeIs . (lg) at twice the rate of large (20g) sprats. The sprats'
5
contained high levels of lipid and when expressed in dry weight terms evacuation
rates were similar for both prey types. When expressed in energy terms the
evacuation rate of sprat was acttially faster than for sarideeI.
The idea that evacuation rate may deperid on the gross biochemical
composition of the prcy receivcs. some support from the results of recent digestion
experiments on whiting at Aberdeen. At a temperature of 13 oe meals of sprats
were eliminated from whiting stomaehs in. an average time of 59 h whereas
similar sized meals of sarideels took 83 h to disappear (A.P.Robb, pers. comm.). At 7
oe elimination times were Ionger and were almost the same for both prey (sprats,
118 h, sandeeI, 115). The. sandeeIs in the Aberdeen experiments were targer, and
the sprats smaller than those, used at Lowestoft. It is known that, the body
composition, and in particular the fat content, of both species varies with size and
season. It is therefore quite likely that the unit energy content of the prey items
used in the Aberdeen experiments differed from that used in Lowestoft. ,
- In addition to biochemical composition it has also been .shown (Sirigh, pers.
comm.) that different prey types can be evacuated at markedly, different rates.
Lugworrß, for example, are evacuated from cod stomaehs several times faster than
are sandeeIs. This is possibly related to the auto-digestion of lugworm by its own
powerful digestive enzymes. Shrimp on the other hand are evacuated more slowly
than sandeeIs, probably due .to the delay caused by the need for the digestive
enzymes to rupture the exoskeletori before digestion of the flesh can begin.
Such large variations in the 'evacuation rates of different prey types, if not
accounted for, could substantially distort estimates of feeding rates and of food
composition derived from stomach content data. It is current practice not to make
allowance for differences in evacuation rate between prey types when calculating
has been largely a. consequence of the lack of
feeding rates for MSVPA. This
supporting cvidence from experimental studies on digestion and evacuation. This
is begining to be rectified, but there is. still a need for
continued commitment to
the experimental programme investigating gastdc evacuation in commercially
exploited fish species.
a
6.2.
l
t
~
'.
.
Variation in feeding level.
,Tables 5.1/3 present the average stomach content weight in grams and Tables
6.1/3 the percentage of empty ,stomachs for cod, ~hiting and saithe in the
different quarters and Years. All data are presented by predator size eIasses, except
for the stornach content weights of whiting where predator age eIasses had to be
used because the 1981 data on size eIasses were not available at the meeting. Note
that size. classes in use have been different in differerit years and that the data are
arranged according to the lower eIass limit.
For cod the average stornach content weights and the percentages of empty
stomaehs seem to have been .quite stable iri the last 20-year period. The variations
are most pronounced in the smallest and largest size classes where the number of
stomaehs sampled is lowest: In the medium size classes the average stornach
coritent weights normally vary with a factor of less than 2. while the. percentages
of empty stomaehs vary with a factor of up to 3. There does not seem to be a marked
trend in the variations. Iri 80 % of the cases where more than 25 stomaehs have
been sampled. the percentage of empty stomaehs is between 5 ·and 15, on' average
9.6.
.
.
,
.,
Looking at the whiting' data. there seem to be. larger variations, both between
different quarters, within the same year. and between,the same -quarters in
different, years. The· stornach content. weights are normally highest. in the' third
quarter. and the" differences are greatest in the youngest age groups, where the
. average weights. increased with a factor of 2..:4 from the first to the third quarter.
There has also been an increase' in the stomach content weights' from 1981 to 1985.
and possibly a further : increase from 1985. to 1986. However. thc 1986 data are, not
complete 'and those. stomaehs that have been worked. -up come -from areas where"
the stoinach content weights are normally high and. the percentage of 'cmpty
6
•
..,-.
stomachs low ( J. Bislop, pers. comm.). 'From 1981 to 1985 thc average weights
.
increased by a factor of about 1.5 - 2.
The perceritage of empty. whiting stomachs has decreased during the same
period. In 1981 the percentage was quite stable for all size CIasses and quarters; on
average 24.0 % of the stomachs were empty. In the first quarter of 1985 this
percentage had dropped to 16.4, and in the third quarter to 5.8, on average 11.1 %
for the whole year. In 1986 the figures where 4.4 % in the first quarter, 0.5 % in
the thirdquarter and 2.5 % on average for the whole Year. But again it should be
noted that the 1986 data are preliminary.
The picture is least CIear for saithe and. here variations are largest but also
the number of stomachs sampled lowest. There does not seem to be a clear trend in
the variations within years or bctween years, ncither for the, average stornach
content wCights nor for the percentagc of empty stomachs. Both parameters vary
with a factor of up to 20 within the same size class.
According to the results of gastric evacuation experiments reported by Peter
Bromley, the rate of evacuation was constant and· independent of the level of
stornach content. Thus the feeding level of a fish population is dependent on thc
proportion of fish which have food in, thc storriach, but. not dependcnt on thc
actual ·amount of food in the stomachs. This should indicate th:ll the fceding level
for cod has been constant over thc last 20 ye:us. For whiting therc might have
been an increase in feeding level from, 1981 ,to 1985/86 because the percentage of
empty stomachs has decreased. For saithe there seem. to bc large variations in
feeding level within each year, but no clear tendency between the different
years.
6~3
,
~
I
Estimates of consumption
.
So far the experimental cvidencc on stornach evacuation ratcs does not allow
fimi conclusions to be drawn on the rates of food consumption in fish populations
in the wild and thc sclcction of values to be applied in MSVPA remains a very
difficult problem. The data obtaincd so far indicate that stornach evacuation nite in
terms of grams per hour is independent of meal size, which. suggests that the
proportion of empty stomaehs might be a better measure of feeding level thim the
average stornach . contents. Howevcr, although digestion rate might iIicrease
rapidly to a maximum at relatively low intensity of feeding, it would scem likely
that therc is also some minimum time required for digestion of any . item after
irigestion.. The applicability of ihis model to the situation in the sea thus depends
on the distribution pattern of individual stornach content weights among thc fish
sampled. ,
.
.
.
.
.
The da ta collectcd so far do not allow an evaluation of this distribution,
because for logistic reasons the stomachs were grouped by size dass before they
were analyzed. Perhaps some carefully designed sampling programmes at a
smaller scale could resolve these matters satisfactorily.
In multispecies assessment it seems prudent not to overestimate effects of
predation, and rates of food consumption should remain on the conservative, side.
So for the time being there appears no reason io change the rates of food intake in
the standard MSVPA, everi if the experimental data suggest higher rather thim
lower food consumption.
However, although the standard ration still is acceptable~
it would seem ,unrealistic. to continue. to use half ration values as was done on
earlier occasions by the Multispecies Assessment Working Group.
\
....
.
7. DATA BASE STOMACH CONTENTS.
"
t·
,.
7.1. Exchange data files.
.
The exchange format for. stornach content data defined ori an earlier. occasion
(Anonymus, 1984) .is copicd in Table 7 for, convenicnce. This format. has bccn
applied effectively in .the . pasi to transfer data, from one system to another arid in
fact copies of all data sets collected after 1981 were available at the meeting and
7
could be treated with one set of computer programs. For, all praciical purposes the
problem of data exchange appetlrS to be solved, but there is still a problem with the
1981 whiting data. These are presently maintained on an old machine, which is
likCly to be replaced shortly, in a fomiat which cnTmot be immediately translated
into exchange tapc, format. Thc group strcssed the, urgent ,need to, address this
problem, because otherwise the data might become lost for all other applications.
..
7.2.
International data base.
Although data Ctln, be effectively exchanged, there is at present no complete
international data base maintairied anywhere and the species coordinators are still
responsible for quality control and updating, of data systems. Thc group feit that it
is bcyond thc possibilities of any of the institutes ,involved to take on the
responsibilty of such a data base. On the other harid, the experience with thc data
base developed by ICES for the International YOI.ing Fish Surveys indicates that it
would not be an easy matter for the computer section of ICES to take on this
responsibility either. It would certainly be a costly and time consuming activity.
Because of the progress that is being made among the various institutes in
exchanging arialysis programs~ it might be more appropriate' to follow these lines
of standarization rather than to indulge iri a major data base projeci. 1I0wever,
complete standarization in collection and processing of data must be ensured,
bCfore riny new stomach sampling programme is started.
8. COOPERATIVE RESEARCH REPORT SSP 1981~
,.
.
A draft has been prepared which includes a fairly detailed description of the
aims, history arid methodology of the project, some of the basic data (sampling
intensity, predator and prey ALKs, prey weights at age etc.) and aselection of the
many possible output tables. This draft will be sent to ICES before the 1988 Council
Meeting. There is still some dis agreement between the coritributors over how
much detailed· information the Report should contain. In particular, some of the
species .coordinators favour the inCIusion of a' set ,of Tables giving the size
distribution of each of the major commercial prey species within each predator
age/sampling area/quarterly combinaiion. As these Tables represent about 30%
(by, weight) of what is at the moment a formidably bulky document, the Group
agreed that adecision ori their irichision should be left to the General Secretary of
ICES.
.
'
9. SPECIAL ISSUE JOURNAL DU CONSEIL.
The 1981 SSP is probably the largest exereise, of its kind that has ever been
undertaken. Thc data have provided riew irisighis irito rates of natural mortality,
which are being takcn irito account by Assessment Working Groups. However, the
results of the project have not yet beeri formally published. Preliminary reports
have been presented to ICES but in. many eases these contain errors and/or are
based on analytical procedures that have since, been revised. Several years aga it
was suggested that the results of the 1981 Project should be presented in ci special
issue of the Journal du Conseil. This procedure would erisure that the results of thc
Project, which were achieved at . considerable expense to several nlüional
laboratories, became established iri the scientific literature and would allow the
Projeci to be viewed as an entitY. Thc plan was io prepare an iniroductory section~
outlining, thc aims and ineihodology, followed by rather ,bdef summaries , of the
results obtained from each prcdator., A suinming up section would deal with the
application of the results to trials of MSVPA.
. This plan has not ye~ been iinplemeritcd. In an· act of despenition some of the
species coordinators have written up ·their work in a more elaborate form .thari
had been, originally proposed~ with a ' view to publishing thCir resuIts
indeperidently. Ir these papers are published there inay" be considerable repetition
of the ainis, methods and global results of the ISSP (although this cO'uld be kept. to ,a
minimum by referring to the proposed Cooperative Research. Report). Although
. 8
this course of actiori is far from ideal. several members of the Group feit that as
such ä long time has elapsed since 1981~ the submission for publication of. selfcontairied speCies reports ought not to be discouraged. However. it was agreed that
the special issue should be granted a stay of. execution; if introductory and
concluding sections could be sent to the Editor of the Journal du Conseil before the
end of 1988. any individual contributioris that had already been submitted could be
appropriately modified.
10. FOLLOW UP.
Adecision on whethcr the 1981 exercise should be repeated in 1991 has to
awaii the results of the forthcoming meeting of the Multispecies Assessment
Working Group. Ir a new. sampling programme is proposed. it should. be borne in
mind that the present. stornach sampling scheme has the following drawbacks with
respect to estimating the average stomach content of the population: .
a) Only fish staying near the bottom are. caught.. This may be especially
important for saithe which is known to perfolm vertical migrations.
b) Sampling has not been at random throughout the. 24 hours. Most
sampIes have been obtained during daytime.. This may bhis the results.
c) It is suspected that both the criteria for excluding prey items presumed
to have been eaten in the trawl from thc sampIes and the classification
of regurgitated stomachs may have differed between countries and
surveys. Better guidelines should b6 prepared.
d) At present stomach contents . within size CIasses are pooled ~md average
weights of food are calculated. Ir some measure of the distribution of the
stomach coritent weights among individual fish could be obtained•. this
might allow the application of more appropriate methods of estimating
consumption rates.
,
e) So far only 5 species of the 9 inc1udcd in MSVPA hilVe been investigated
thoroughly in respect of food composition; Although the others are
probably insignificant in respect of feeding on juveniles above age 1.
predation ori O-group might be important. At present the O-group phase
is excluded from MSVPA. but it might be possible to inchide at least the
second half of the first year of life. In that case. extension of the
programme to inc1ude other species as weil might be considered.
. These problems deserve further consideration prior to arepetition of the
1981 exercise.
' .
.
12. REFERENCES.
Anonymus. 1984 - Report of. the meeting of the Coordinators of the
Stomach Sampling project 1981. ICES C.M. ,1984/G:37.
Bromlcy.P.J.•1986 - An appraisal of the MSVPA feeding data. Working
paper MSVPA Working Group 1986.
Bromley.P.J.•1987 - The effects of food type. meal size and body weight on
digestion and ga.stric eva.cuation in turbut. Scophthalmus maximus
L. J. Fish. Biol. 30. 501-512.
Bromley.P.J.• 1988
.Gastdc digestion äöd evacuation in whiting
(Merlangius merlangus),J. Fish. Biot. (In press).
Gislason.H. and Sparre.P.• 1987 - Some., theoreiicalconsideriüions on the
implementation of Multispecies Virtual Population Analysis in ICES.
ICES CM. 1987/G:52.
9
YES
M
S
Use the number 01 stomaehs sampled
to calculate a weighted average 01 the
G's estimated in individual years
v
P
A
•
1980
M
<
I
S
V
P
A
,
,
~.
I
'.
f
l,
I
Fig. 1
The computational procedure for estimation of suitability
coefficents based on a time series of food composition data.
10
Table 1.1.1
Number of stomaehs sampled by size c1ass of cod, area and quarter in 1985.
Size c1ass
70
80 100
150
200 250
300 350
400 500 600 700
800 1000
Total
Quarter 1
-------------------------------------- .._-----------------------------------------------------------------------------------
Area 1
Area2
Area3
Area4
Area5
Area 6
Area 7
Total
3
58
131
27
13
2
2
5
3
66
10
48 115
6
5
31
58
2
1
82 88
28 50
41
91
254 449
1
130 103
129
116
68
51
23
2
814
49
19
73
8
177
28
20
16
45
12
147
10
36
43
36
27
104
3
6
8
6
21
95
1
10
2
8
12
54
3
13
9
8
6
12
6
17
17
13
3
34
3
8
6
1
12
1
324
128
289
96
898
156
484 353
378
253 157
105
110
30
2705
Quarter 3
---------------------------------------------------------------------------------------------------
•
Area 1
Area2
Area3
Area4
Area5
Area6
Area 7
Total
10
34
10
41
9
34
70
2
2
2
6
5
2
6
13
4
2
1
12
40
10
1
14
69
6
2
12
2
6
611
542
64
301
15
856
172
484 311 186 120
79
15
2561
800 1000
Total
49
16
9
43
13
33
1
102
16
94 139
202 130
12 10
76 56
1
103 70
40
15
167
110
14
53
104
36
91
217
528 420
51
8
1
13
1
173 105
7
9
66
28
6
29
26
7
Table 1.1.2
Number of stomaehs sampled by size c1ass of cod, area and quarter in 1986.
Size c1ass
70
80 100
150
200 250
300 350
400 500 600 700
Quarter 1
------------------------------------------------.._---------------------------------------------------
I.
~
.
Area 1
Area2
Area3
Area4
Area5
Area6
Area 7
Total
2
2
95
38
37
1
247
54
7
127
18
148
30
265
44
4
13
3
29
12
2
68
23
29
8
144 139
6
25
24
11
12
7
1
27
11
43
36
17
9
1
6
16
472
639
311
194
93
128
214 106 88
33
10
3
7
1
1
20
4
2
17
2
18 53 147
21
7
3
315
198 244
58
2
3
38
6
60
4
22
40
13
38
12
20
1
5
18
3
16
8
12
2
584
407
127
408
117
1140
194
171
146
64
2977
Quarter 3
-------------------------------------------------------------------------------------
Areal
Area2
Area3
Area4
Area5
Area6
Area 7
10
Total
1
10
11
82
1
36
3
9
22
53
13
21
204
58 38
277 229
34 63
143 164
6
17
206 334
101
90
23
25
124 54
6
37
101 42
14 17
287 162
58 27
825
644 333
935
65 137
71
59
1
6
23
13
13
55
3
15
14
243
26
34
2
4
6
13
60
9
1
5
1
1
7
232 114
84
70
46
28
6
15
3
9
1
2
503
986
157
549
68
1089
381
15
3733
1
3
11
Table 1.1.3
Number of stomaehs sampled by size dass of cod, area and quarter in 1987.
Size dass
70
80 100
150
200
250
300 350
400 500 600 700
800 1000
Total
Quarter 1
-------------------------------------------------------------------------------------------------------------------------------------
Area 1
Area2
Area3
Area4
Area5
Area 6
Area7
4
26
2
8
1
29
19
4
38
34
15
5
98
15
Total
89
209
24
72
22
42
25
112
17
100
155
26
89
14
65
34
314 483
130
80
66
102
16
59
33
90
38
24
80
25
67
33
76
7
10
26
27
86
14
18
5
1
6
19
35
1
30
486 357
246
85
53
2
5
1
9
6
20
5
3
5
3
14
7
29
4
15
5
21
3
50
84
15
4
1
21
41
503
470
194
397
142
616
175
2497
Quarter 3
---------------------------------------------------------------------------------------------------------
•
Area 1
Area2
Area 3
Area4
Area5
Area 6
Area 7
Total
16
48
12
12
36 30
123
95
27
51
85
51
17 22
122 244
101 128
32
122
37
120
35
248
109
134
123
23
153
23
168
122
173
152
18
99
31
123
95
89
477
703
746
691
1
1
2
3
655
57
28
9
37
13
4
1
2
1
3
28
24
56
34
42
8
6
6
9
13
3
230
87
61
22
5
5
1
7
1
1
1
3
3
586
730
182
544
163
990
613
53
13
3808
11
12
Table 1.2.1
Summary of stomach contents by predator by age class. area and quarter.
YEAR: 1985
PREDATOR :COD
.AGECLASS
0
GENERALRESULTS
Nr of sL sarnpled
Nr of SI. with food
Nr of regurgil. SI.
Nr of empty SL
% empty sL
Mean length
Total wghl alt prey
Total nr of prey iterns
Average prey wghl
I.
I
I
I
I.
I
WEIGIIT % BY MAJOR TAXA
rnIDAR!A
ANNELllDA
GASIROPODA
BIVALVIA
CEPHALOPODA
CRUSTACEA
MYSlDA
VALVIFERA
GAMMARIDEA
EUPHAUSIACEA
CARIDEA
ASTACIDEA
ANOMURA
OXYRHYNCHA
CANCRIDEA
BRACHYRIIYNCHA
OTHER CRUST. U)
EOIIURA
EOlINODERMATA
UROOlORDATA
GNATIIOSTOMATAI
OTIIER*)
UNKNOWN
WEIGIIT % COMMERaAL SPEC.
G. morhua
M. aeglefmus
M. merlangus
T. esmarkü
C. harengus
S. sprauus
AMMODYTIDAE
P. platessa
S. solea
L limanda
S. scomber
N. norvegicus
C. crangon
QUARTER: 1
2
3
ALL AREAS
4
5
6l-
145
132
6
9
6.207
17.620
1.015
3.141
0.323
1870
1512
174
184
9.840
32.720
8.947
5.146
1.739
346
295
17
31
8.960
53.290
43.257
12.997
3.328
211
184
4
23
10.900
71.420
95.384
13.715
6.955
55
47
1
6
10.909
80.530
112.997
10.869
10.396
0.24
20.77
3.47
5.42
0.05
4.08
0.79
5.32
0.64
25.79
0.03
0.08
0.10
0.06
11.87
1.48
5.36
1.47
0.44
4.91
0.00
0.04
0.18
0.09
62.92
0.10
0.00
0.01
1.34
0.34
2.45
0.12
11.98
0.00
0.03
0.00
0.01
3.12
1.45
2.13
1.44
0.83
2.95
0.00
0.01
0.03
0.16
83.50
0.05
0.00
0.00
1.40
0.44
1.47
0.03
5.92
0.00
0.02
0.00
0.00
0.71
1.45
0.76
0.57
0.86
1.54
0.00
0.00
0.01
0.29
90.43
0.00
.00
1.58
0.47
1.00
0.01
5.76
0.00
0.01
0.00
0.00
0.38
1.33
0.42
0.39
1.43
1.80
0.00
0.07
1.51
0.05
0.15
3.32
2.37
0.00
0.00
0.20
90.96
0.00
0.00
0.01
90.81
0.02
0.7
0.39
7.08
4.40
16.23
12.99
1.30
4.74
0.47
0.85
3.26
0.98
7.89
9.00
28.21
15.44
1.26
4.05
0.47
0.68
5.19
10.93
1.41
5.57
1.43
1.40
1.01
10.87
7.97
26.08
20.76
1.28
2.33
1.72
0.23
7.02
0.14
1.45
0.14
1.26
10.98
7.95
19.27
23.16
1.26
1.43
5.15
0.11
9.29
0.28
1.33
0.04
1.77
5.40
13.13
4.62
17.22
0.71
0.14
20.75
0.05
17.77
0.26
1.51
0.01
40.41
0.75
0.05
0.70
0.00
30.34
sm
0.15
0.06
3.31
0.04
0.39
0.75
28.51
0.04
0.55
5.00
6.27
0.22
1.16
0.13
*) Include PHAEOPHYTA. PORIFERA. CTENOPHORA. RHYNCHOCOELA, SCAPHOPODA, PYCNOGONIDA. SlPUNCUlA.
PRIAPUllDA. CEPllALOCHORDATA
*.) Include CUMACEA. HYPERI1DAE, OXYSTOMATA
78
66
7
6
7.692
96.880
166.168
7.608
21.840
1.28
0.31
0.11
0.00
7.48
13
Table 1.2.2
Summary of stomach contcnlS by prcdalor by age dass, area and quarter.
PREDATOR: COD
.AGECLASS
GENERAL RESULTS
Nr of st. samplcd
Nr of st. with food
Nr of regurgit. st.
Nr of empty st.
% ernpty st.
Mean length
Total wght all prey
Total nr of prey
Average prey wght
•
~e
YEAR: 1985
0
106
100
0
6
5.660
.180
0.125
1.610
0.078
WElGlIT % BY MAJOR TAXA
<NIDARIA
Am.'ELlIDA
16.96
GASIROPODA
BIVALVIA
CEPHALOPODA
CRUSTACEA
69.12
MYSIDA
0.20
CUMACEA
0.85
VALVIFERA
GAMMARIDEA
EUPHAUSIACEA
CARIDEA
ASTAODEA
ANOMURA
OXYRHYNC1IA
CANCRIDEA
BRACHYRHYNCIIA
OTIIER CRUST. U)
EOllURA
PRlAPULIDA
ECHINODERMATA
GNATHOSfOMATA
OTHERS*)
lJ!','KNOWN
1.32
42.20
1.49
5.17
5.25
12.55
13.92
WElGHT % COMMERCIAL SPEC.
G. morhua
M. aeglefmus
M. rnerlangus
T. esmarkii
9.48
C. harengus
S sprauus
AMMODYlIDAE
P. platessa
1.. lirnanda
S. scornber
C. crangon
39.58
QUARTER: 3
2
3
ALL AREAS
4
5
6t
356
273
39
46
12.921
26.170
2.189
3.939
0.556
1630
1061
413
157
9.632
39.160
12.891
4.811
2.679
270
204
33
34
12.593
63.450
59.672
5.957
10.017
130
95
17
17
13.077
77.880
103.408
7.388
13.997
28
20
4
3
10.714
90.400
152.646
9.262
16.481
42
31
6
4
9.524
96.590
200.950
10.725
18.736
0.00
7.80
2.92
3.51
0.01
42.31
0.19
0.01
0.10
0.07
0.56
2.58
0.81
15.41
5.95
4.16
12.40
0.10
0.23
0.68
0.14
42.32
0.06
0.02
0.00
7.00
0.65
1.52
1.45
29.17
0.04
0.16
4.78
0.06
0.21
755
20.62
0.00
0.11
6.82
0.00
0.20
2.42
25.20
0.00
0.02
.57
0.00
0.18
0.80
24.14
0.00
4.83
0.00
0.10
0.41
20.46
0.05
0.01
0.11
0.73
6.21
5.35
2.29
7.08
7.30
0.08
0.04
0.06
0.46
59.60
0.05
0.00
0.00
0.00
0.00
0.13
3.02
1.38
0.49
10.31
5.23
0.01
0.00
0.00
0.19
66.40
0.02
0.00
0.00
0.00
0.00
0.00
0.01
0.11
4.79
1.01
0.18
15.06
4.04
0.07
0.09
4.81
0.39
0.06
16.04
2.75
0.02
0.05
3.30
0.17
0.03
15.29
1.61
0.00
0.02
65.21
0.01
0.00
68.29
0.01
0.00
74.19
0.00
1.76
7.75
2.29
5.14
5.41
0.02
13.25
0.02
1.27
0.35
8.64
8.50
15.23
4.94
0.31
10.20
0.30
1.16
8.34
6.00
5.28
1.87
4.99
6.14
5.87
5.59
0.51
4.51
3.46
7.40
7.76
0.53
3.79
0.00
0.65
0.40
7.01
6.41
0.00
0.40
1.40
7.87
8.01
0.00
0.24
3.32
7.14
6.86
0.07
4.94
11.38
9.71
7.12
5.06
0.02
1.91
1.66
2.73
0.79
0.00
*) Include PHAEOPHYTA, SCAPHOPODA, PYCNOGONIDA, EcroPROCTA, UROCHORDATA, CEPHALOCHORDATA, AGNATIIA
**) Include HYPERllDEA, OXYSTOMATA
14
Table 1.2.3
Summary of stomach contents by predator by age class. area and quarter.
YEAR: 1986
PREDATOR: COD
.AGECLASS
0
GENERAL RESULTS
Nr of sL sampled
Nr of st. with food
Nr of regurgiL st.
Nr of empty sL
% empty sL
Mean length
Total wght all prey
Total nr of preY
Average prey wght
•
,
.
I.
I
.~
WElGlIT % BY MAJOR TAXA
rnIDARIA
M'NELLIDA
GASIROPODA
BIVALVIA
CEPHALOPODA
CRUSTACEA
MYSIDA
GAMMARIDEA
EUPHAUSIACEA
CARIDEA
ASTACIDEA
ANOMURA
OXYRlIYNCHA
CANCRIDEA
BRACHYRHYNCHA
OTIIER CRUST. **)
EOllURA
EOIINODERMATA
CEPHALOCHORDATA
GNATHosroMATA I
OTIIERS*)
WEIGHT % COMMERCIAL SPEC.
G. morhua
M. aeglefmus
M. merlangus
T. esmarkii
C. harengus
S. sprattus
AMMODYlIDAE
P. platessa
S. solea
L limanda
S. scomber
C. crangon
ALL AREAS
QUARTER: 1
2
3
4
5
6t
273
210
37
25
9.158
33.950
8.794
3.832
2.295
598
487
53
59
9.866
49.110
26.408
5.718
4.619
280
242
7
30
10.714
64.920
54.870
6.738
8.144
139
116
3
20
14.388
80.150
88.996
6.055
14.697
137
105
10
22
16.058
93.580
119.989
6.612
18.147
1.37
2.95
1.31
1.46
0.74
14.83
0.01
0.01
0.40
6.48
0.48
4.68
0.92
0.27
1.53
0.05
0.00
0.20
0.00
77.11
0.00
1.29
3.53
1.26
0.31
0.53
9.31
0.00
0.00
0.10
2.24
1.14
2.19
0.56
0.53
2.51
0.03
0.00
0.33
0.00
83.42
0.01
0.20
2.85
0.17
0.11
0.43
9.27
0.00
0.00
0.00
1.41
1.67
2.17
0.18
0.72
3.10
0.01
0.02
0.21
0.04
2.90
0.31
0.06
0.17
7.93
0.00
0.00
0.00
0.65
2.10
1.35
0.07
0.63
3.13
0.00
0.01
0.42
0.03
2.19
0.11
0.04
0.05
7.51
0.00
0.00
0.00
0.26
2.84
1.20
0.03
0.36
2.82
0.00
0.00
0.30
86.12
0.02
88.13
0.02
89.75
0.01
0.09
0.51
0.15
14.77
6.70
18.53
6.31
2.09
16.09
0.04
0.27
0.32
9.79
2.32
2.63
11.04
9.28
20.66
13.26
4.26
6.56
0.61
1.08
3.76
0.00
0.87
3.51
7.70
10.71
16.68
21.12
2.68
1.73
1.77
1.89
7.31
0.32
0.72
4.38
10.10
lQ.42
9.44
30.24
0.65
0.44
1.86
1.37
8.17
1.27
0.29
2.81
7.28
8.50
7.25
32.21
0.17
0.27
3.45
1.66
12.01
1.62
0.09
1550
1082
321
147
9.484
19.010
1.245
2.557
0.487
9.05
1.62
3.27
0.45
39.61
0.37
0.29
27.72
0.02
7.80
0.22
0.09
3.08
0.02
0.14
0.04
0.08
45.73
0.00
1.09
0.77
0.73
2.62
1.11
19.02
*) Include RHYNCHOCOElA. SCAPHOPODA. PRIAPUUDA. EcroPROCTA, UROCHORDATA
**) Include CUMACEA. VALVIFERA. OXYSTOMATA
15
Table 1.2.4
Summary of stomach contents by predator by age class, area and quancr.
YEAR: 1986
PREDATOR: COD
.AGECLASS
GENERAL RESULTS
Nr of s1. sampled
Nr of st. with food
Nr of regurgi1. st.
Nr of ernpty S1.
% empty s1.
Mean length
Total wght an prey
Total nr of prey
Average prey wght
0
34
26
0
8
23.529
8.380
0.069
0.717
0.096
QUARTER: 3
2
3022
2416
187
421
13.931
28.340
3.747
4.054
0.924
133
102
18
11
8.271
42.650
14.810
4.288
3.454
3
408
299
77
31
7.598
56.010
35.647
4.693
7.596
ALL AREAS
4
5
6i-
43
36
5
2
4.651
91.320
144.029
8.435
17.076
21
1
0
0.00
104.520
342.188
10.415
32.855
4.23
0.18
0.02
0.05
28.62
2.18
0.37
0.02
0.01
21.66
1.91
0.05
0.00
0.00
10.06
0.01
0.51
14.01
0.27
0.18
4.50
9.13
0.01
0.01
0.08
9.68
0.14
0.21
5.05
6.46
0.03
0.00
0.01
0.05
2.61
0.02
0.03
5.14
2.19
0.00
0.26
0.03
0.01
0.00
70.00
0.00
0.01
66.87
75.76
0.00
87.97
0.06
6.90
2.73
23.47
10.56
2.07'
0.27
0.04
0.08
7.99
0.32
3.44
5.86
16.43
19.31
2.62
0.38
0.59
4.45
5.79
3.72
37.01
5.30
2.25
0.08
6.23
2.06
3.26
57.88
0.69
6.58
1.76
4.16
4.20
1.94
2.24
1.88
72
59
11
3
4.167
74.950
80.985
5.902
13.721
23
WEIGIIT % BY MAJOR TAXA
CNIDARIA
•
--
-
M'NElllDA
GASTROPODA
BIVALVIA
CEPHALOPODA
CRUSTACEA
MYSIDA
VALVIFERA
CARIDEA
ASTACIDEA
ANOMURA
OXYRHYNCHA
CANCRIDEA
BRACHYRHYNCHA
OTIIER CRUST•••)
EOITURA
PRIAPULIDA
ECHINODERMATA
UROQlORDATA
GNAlHOSTOMATAI
OTIIERS*)
UNKNOWN
1.12
63.57
1.79
55.00
1.72
5.06
35.31
WEIGHT % COMMERClAL SPEC.
G. morhua
18.89
M. aeglefmus
M. merlangus
T. esmarkü
C. harengus
AMMODYTIDAE
P. platessa
S. solea
M. kitt
1.. limanda
N. norvegicus
C. crangon
0.08
5.73
0.31
6.05
0.04
45.61
0.04
0.03
5.27
4.63
12.40
2.06
2.98
18.00
0.20
0.15
0.36
0.32
0.15
41.15
0.04
0.01
0.02
4.53
0.40
2.52
0.04
25.47
0.00
0.08
2.27
2.56
3.80
1.23
3.75
11.76
0.00
0.12
0.01
0.21
0.00
66.65
0.00
0.03
0.02
1.95
1.09
3.94
5.89
16.66
0.18
0.88
0.12
6.25
2.35
23.79
8.29
6.81
0.37
0.40
1.57
0.05
2.34
4.94
0.00
0.87
0.00
6.77
0.13
0.54
0.18
22.06
0.00
0.09
0.94
5.23
1.81
0.77
3.93
9.29
0.00
0.04
0.08
.) Include RHYNQIOCOELA, SCAPHOPODA.PYCNOGONIDA. CEPHALOOlORDATA
..) Include CUMACEA, GAMMARIDEA. IlYPERlIDEA. EUPHAUSIACEA. OXYSTOMATA
16
Table 1.2.5
Summary of stomach contents by predator by age eIass. area and quarter.
.AGECLASS
QUARTER: 1
YEAR: 1987
PREDATOR : COD
2
0
GENERALRESULTS
Nr of S1. samplcd
Nr of st. with food
Nr of regurgiL st.
Nr of empty sL
% ernpty st.
Mean lcngth
Total wght all prey
Total nr of prey
Average prey wght
607
483
58
65
10.108
20.200
1.110
3.296
0.355
1632
1233
241
150
9.191
33.660
6.760
3.593
1.881
3
88
67
13
7
7.955
43.700
14.911
4.161
3.585
ALL AREAS
4
5
6t
126
101
14
11
8.730
70.710
60.335
5.564
10.843
37
30
4
3
8.108
81.450
77.018
5.648
13.646
76
55
9
11
14.474
98.230
115.202
5.219
22.074
0.00
2.26
0.60
0.19
0.59
6.69
2.20
0.11
0.06
0.14
3.81
WEIGllT % BYMAJOR TAXA
CNIDARlA
•
i~
ANNEUlDA
GASlROPODA
BIVALVIA
CEPHALOPODA
CRUSTACEA
MYSIDA
GAMMARIDEA
EUPHAUSIACEA
CARIDEA
ASTACIDEA
ANOMURA
OXYRHYNCHA
CANCRIDEA
BRACHYRHYNCIIA
OTHER CRUST. ..)
ECHlNODERMATA
UROCHORDATA
GNATHOSTOMATA
OTIffiRS·)
UNKNOWN
WEIGHT % COMMERCIAL SPEC.
G. adus momua
M. aeglefinus
M. merlangus
T. esmarkü
C. harengus
S. sprattus
AMMODYTIDAE
P. platessa
S. solea
L limanda
S. scomber
C. crangon
15.80
0.52
6.42
0.17
38.88
0.20
0.32
2.20
22.45
0.00
7.34
1.81
0.43
4.00
0.07
0.03
38.00
0.06
0.12
0.15
2.62
2.71
5.52
5.49
0.06
11.67
0.06
0.12
4.83
-.~
.) Inc1ude SCAPHOPODA. EClUURA. PR1APUUDA
..) Include VALVlFERA. OXYSTOMATA
0.06
4.94
0.15
3.03
0.43
23.34
0.01
0.07
1.02
7.00
1.55
6.71
1.08
0.67
5.16
0.02
0.06
0.09
67.18
0.05
0.08
0.08
3.29
0.92
1.14
0.51
18.53
0.00
0.01
0.23
4.91
3.55
4.86
0.42
0.40
4.14
0.01
0.02
0.09
15.38
0.01
0.03
0.01
2.34
0.74
0.30
0.69
7.44
0.00
0.00
0.00
0.88
3.41
0.65
0.01
0.15
2.33
0.00
0.00
0.00
88.41
0.00
0.00
1.23
8.46
10.62
11.95
9.35
0.19
10.92
0.33
1.01
2.10
0.05
1.42
1.93
8.16
18.78
8.63
9.79
0.24
6.45
0.91
1.03
8.31
0.12
1.02
8.48
13.85
15.22
2.64
12.27
0.02
1.07
7.76
0.24
17.05
0.03
0.21
0.41
2.72
0.36
0.00
0.16
2.99
0.17
1.13
0.22
0.00
0.00
89.65
93.62
10.81
13.08
9.61
1.98
14.52
0.00
0.57
10.96
0.14
18.24
0.02
0.10
17.25
4.74
11.73
0.66
9.48
0.21
2.08
0.18
23.82
0.04
19.31
0.02
0.02
17
Table 1.2.6
Summary of stomaeh contents by predator by age dass, area and quarter.
YEAR: 1987
PREDATOR : eOD
.AGECLASS
GEI\'ERALRESULTS
Nr of sL sampled
Nr of sL with food
Nr of regurgiL sL
Nr of ernpty sL
% empty sL
Mean length
Total wght all prey
Total nr of prey
Average prey wght
•
0
2
3
ALL AREAS
4
5
6t
3
2
64
1
33.333
1762
1429
205
269
15.267
1837
1363
6
267
14.535
47
35
12
7
14.894
106
79
4
16
15.094
37
28
2
3
8.108
2
11.111
0.085
0.743
0.115
3.671
4.665
0.787
12.349
4.767
2.590
43.169
5.063
8.526
92.196
5.690
16.204
167.863
9.205
18.236
255.689
11.240
22.747
4.98
0.09
0.02
0.00
4.96
0.00
0.02
0.02
5.56
1.42
0.11
0.04
0.01
24.98
0.00
2.35
2.72
1.53
1.31
6.57
10.50
0.00
0.00
15.11
0.00
0.36
4.27
0.60
0.71
2.82
6.35
0.00
12.76
9.24
0.06
3.28
0.71
0.33
1.71
6.67
0.00
0.00
3.64
1.57
0.06
2.02
1.95
0.00
0.16
0.00
0.16
0.00
0.32
0.03
0.07
0.19
69.52
0.01
79.72
0.00
81.29
0.00
88.95
7.80
7.99
10.51
9.11
11.57
0.17
3.73
1.55
0.00
9.62
0.39
12.19
12.94
17.85
9.89
9.38
0.08
2.35
0.67
20.41
5.80
18.06
5.34
13.28
0.01
4.71
0.07
6.49
0.93
7.92
0.20
WEIGIIT % BY MAJOR TAXA
ANNEU.1DA
5.80
GASlROPODA
BlVALVIA
4.07
CEPHALOPODA
PYCNOGONIDA
CRUSTACEA
72.46
GAMMARIDEA
CARIDEA
72.46
ASTACIDEA
ANOMURA
OXYRHYNCHA
CANCRlDEA
BRACHYRHYNCIIA
OTHER CRUST.U)
EOllURA
PRIAPULlDA
EOIINODERMATA
UROOIORDATA
AGNATI-IA
GNATHOSTOMATA
OTHERS·)
UNKNOWN
QUARTER: 3
0.37
21.74
WEIGlIT % COMMERCIAL SPEaES
G. morhua
0.00
M. aeglefmus
M. merlangus
T. esmarkü
C. harengus
S. sprauus
AMMODYTIDAE
P. platessa
S. solea
0.12
1.. limanda
S. scomber
C. crangon
10.01
0.34
2.20
0.02
0.08
46.75
0.22
4.46
1.73
20.85
2.41
4.04
12.91
0.13
0.04
0.31
0.30
0.02
0.31
37.24
0.03
0.15
7.37
0.27
0.25
0.03
0.02
33.27
0.04
3.43
1.85
7.26
1.24
7.88
11.54
0.03
0.00
0.03
0.33
0.04
0.00
56.36
0.00
0.04
0.02
2.59
3.09
5.48
6.03
0.01
12.45
0.09
0.08
1.59
1.95
3.86
4.54
9.63
13.37
0.09
7.67
0.32
0.05
6.58
0.35
0.07
.) Indude CNlDARIA, SCAPHOPODA, CEPI-lALOCHORDATA
U) Indude BALANIDAE, MYSIDA. VALVIFERA, OXYSTOMATA
18
14
9.70
4.03
0.97
17.50
12.97
3.20
0.02
18
Table 1.3.1
Average stornaeh eontent weight (g) per 1000 fish by age class of commercially exploited prey species by predator age class, area
and quarter.
YEAR: 1985
PREDATOR: COD
.AGECLASS
•
0
Nr of sL with food
Fraetion ernpty
Mean length
136
0.05
17.37
PREY : ALL SPECIES
All classes
975.
•
3
1527
0.09
33.07
293
0.12
53.83
4
162
0.10
71.49
5
53
0.05
79.01
6t-
65
0.09
95.09
39432.
88869.
107687.
166507.
PREY:GADUS MORHUA
Age class 1
2
3
22.
1.
36.
83.
TOTAL
23.
118.
38.
314.
3.
355.
18.
580.
8.
606.
88.
2342.
18.
2447.
474.
88.
1.
1184.
1423.
37.
4.
563.
2648.
1538.
5992.
245.
32.
1.
7808.
1600.
7678.
460.
60.
3.
9800.
678.
6310.
666.
89.
5.
7748.
270.
232.
21.
6.
672.
1847.
157.
17.
O.
O.
2.
490.
1753.
604.
129.
26.
31.
3033.
1147.
4185.
1335.
270.
56.
69.
7061.
1589.
14616.
6304.
1969.
702.
542.
25722.
PREY: MELANOGRAMMUS AEGLEFINUS
Age class 1
2
3
4
5
TOTAL
PREY : MERLANGIUS MERLANGUS
Age class 1
27.
2
3
4
5
6
27.
TOTAL
TOTAL
'
2
ALL AREAS
10983.
PREY : TRISOPTERUS ESMARKI
Age class 0
1
2
3
4
- ..
QUARTER: 1
PREY: CLUPEA HARENGUS
Age class 1
2
3
4
5
6
TOTAL
PREY : CLUPEA SPRATTUS
Age class 1
2
3
4
5
6
TOTAL
PREY : AMMODYTIDAE
Age class 1
2
3
4
6
TOTAL
PREY:OTHER
All classes
O.
1.
3.
4.
11.
2.
528.
2.
2698.
1.
848.
290.
29.
3.
1171.
7709.
6089.
379.
21.
14197.
17445.
21446.
1533.
79.
40509.
14483.
17079.
1176.
62.
32816.
8284.
7066.
394.
21.
15766.
111.
1258.
149.
26.
1.
1.
1545.
62.
1738.
3018.
1071.
153.
69.
6110.
1424.
9732.
6216.
1438.
607.
19418.
3275.
11978.
8729.
1765.
1109.
26858.
7257.
10700.
5848.
1354.
607.
25767.
52.
69.
53.
7.
135.
73.
188.
200.
79.
49.
6.
4.
364.
149.
17.
6.
812.
370.
43.
3.
O.
32.
O.
O.
O.
O.
O.
O.
O.
13.
182.
429.
335.
536.
1234.
27.
146.
376.
24.
389.
481.
62.
1.
1.
1.
28.
12.
561;
162.
1094.
1316.
1323.
186.
2.
276.
3102.
903.
6411.
12137.
14308.
1.
1074.
1278.
165•.
3.
235.
·2754.
27255.
199.
153.
14.
O.
366.
87457.
19
Table 1.3.2
Average stomach content weight (g) per 1000 fish by age dass of commercially exploited prey species by predator age
dass, area and quarter.
YEAR: 1985
PREDATOR: COD
.AGECLASS
Nr of sL with food
Fraction ernpty
Mean length
0
100
0.06
7.11
PREY : ALL SPECIES
All dasses
56.
e
2
3
1237
0.10
39.24
101
0.11
62.26
ALL AREAS
4
52
0.08
76.68
5
16
0.00
83.49
6t
27
0.09
94.59
2172.
12460.
57787.
114724.
165076.
12.
36.
12.
36.
36.
164.
618.
7.
826.
235.
2033.
7749.
70.
10086.
185.
2262.
12446.
55.
14948.
PREY: MELANOGRAMMUS AEGLEFINUS
688.
Age dass 0
57.
o.
291.
1
149.
2
1127.
57.
TOTAL
771.
2010.
2495.
5276.
283.
3480.
7091.
10855.
189.
1496.
4466.
6151.
136.
1795.
4269.
6201.
PREY : MERLANGlUS MERLANGUS
Age dass 0
18.
1
2
3
4
5
6
18.
TOTAL
43.
3276.
4854.
793.
271.
49.
11.
9298.
84.
3374.
3413.
272.
132.
39.
8.
7323.
56.
3477.
3533.
116.
26.
992.
159.
1432.
1559.
218.
59.
5.
1.
3433.
PREY : TRISOPTERUS ESMARKI
O.
7.
Age dass 0
20.
1
2
6.
O.
3
O.
33.
TOTAL
136.
1314.
312.
2.
1765.
376.
5078.
821.
5.
6280.
304.
1374.
137.
1.
1815.
105.
682.
106.
1.
893.
16.
787.
64.
PREY: CLUPEA HARENGUS
Age dass 1
212.
2
3.
3
4
5
215.
TOTAL
167.
280.
65.
141.
1.
654.
92.
1950.
535.
770.
3.
3349.
10.
2712.
506.
828.
3.
4058.
O.
1640.
737.
1537.
6.
3919.
28.
2682.
537.
1017.
4.
4268.
O.
3.
1.
27.
1.
29.
177.
5.
9.
5.
1009.
120.
65.
28.
1436.
84.
11.
3.
O.
O.
O.
12.
2.
196.
1235.
1536.
608.
224.
279.
1639.
6623.
37082.
78004.
131618.
204375.
PREY:GADUS MORHUA
Age dass 0
1
2
3
TOTAL
•
248
0.14
26.55
QUARTER: 3
PREY: CLUPEA SPRATTUS
Age elass 1
2
3
TOTAL
PREY: AMMODYTlDAE
Age elass 0
1
2
3
4
5
6
TOTAL .
PREY:OTHER
All dasses
55.
O.
3.
O.
203.
505.
262.
18.
4.
o.
232403.
. 773.
8432.
9205.
7208.
O.
867.
5.
O.
5.
579.
29.
1.
214.
9.
O.
262.
15.
1.
O.
O.
20
Table 1.3.3
Average stomach content weight (g) per 1000 fish by age class of commercially exploited prey species by predator age
class, area and quarter.
YEAR: 1986
PREDATOR: COD
.AGECLASS
0
2
Nr of sL with food
Fraction ernpty
Mean length
1088
0.09
18.08
PREY:ALL SPECIES
All classes
1356.
4
5
559
0.09
49.66
196
0.12
65.17
110
0.14
76.64
6+86
0.18
90.96
44245.
68626.
94571.
46.
1.
3008.
207.
47.
3215.
76.
62.
40.
178.
385.
721.
387.
1492.
214.
883.
795.
1891.
PREY: MELANOGRAMMUS AEGLEFINUS
Age class 1
13.
1268.
25.
2
3
TOTAL
13.
1293.
2808.
100.
46.
2955.
3181.
1024.
369.
4574.
3872.
3667.
1398.
8937.
5297.
4693.
1929.
1l919.
PREY : MERLANGIUS MERLANGUS
7.
Age class 1
2
3
4
5
6
7.
TOTAL
1022.
4769.
586.
351.
24.
2.
1.
5733.
903.
730.
742.
127.
41.
28.
2571.
1128.
1545.
965.
166.
57.
34.
3895.
1l33.
2049.
1285.
202.
57.
20.
4745.
743.
56.
1.
2713.
445.
18.
11496.
2988.
149.
3.
14636.
14002.
1207.
45.
1.
15255.
PREY : CLUPEA HARENGUS
O.
Age class 1
54.
2
O.
3
4
5
·6
54.
TOTAL
•
3
29954.
PREY: TRISOPTERUS ESMARKI
Age class 1
2
3
4
O.
TOTAL
"-
202
0.10
33.96
ALL AREAS
9047.
PREY:GADUS MORHUA
Age class 1
2
3
TOTAL
•
QUARTER: 1
PREY: CLUPEA SPRATTUS
Age class 1
O.
2
6.
3
15.
4
4.
5
O.
6
TOTAL
PREY: AMMODYTIDAE
Age class 1
2
3
4
TOTAL
PREY:OTHER
All classes
933.
85.
4.
O.
801.
3176.
10379.
3173.
143.
3.
13698.
2.
621.
46.
112.
58.
2.
840.
2.
1199.
841.
368.
84.
5.
2499.
O.
O.
4251.
6187.
1696.
100.
27.
12262.
5465.
14104.
3454.
177.
56.
23255.
6018.
14874.
3831.
308.
62.
25092.
1.
29.
55.
14.
O.
O.
12.
23.
6.
O.
O.
3.
8.
2.
O.
O.
O.
O.
99.
41.
13.
936.
76.
201.
65.
1.
1l9.
lOS.
4.
O.
26.
2.
68.
218.
55.
3.
1.
346.
159.
12.
1404.
291.
O.
O.
8.
346.
780.
196.
7.
3.
1340.
2041.
198.
1.
O.
O.
O.
O.
O.
171.
1695.
2240.
1012.
266.
227.
108S.
3003.
8795.
9850.
16103.
35427.
22
Table 1.3.5
Average stomach content weight (g) per 1000 fish by age dass of commercially exploited prey species
by predator age dass, area and quarter.
YEAR: 1987
PREDATOR : COD
AGECLASS
0
Nr of sL with food
% empty stomaehs
Mean length
0
0.00
0.00
PREY:ALL SPECIES
All dasses
2
466
0.10
20.35
1190.
PREY:GADUS MORHUA
Age dass 1
2
3
TOTAL
•
2.
1184
0.10
34.22
2.
PREY: MERLANGIUS MERLANGUS
Age dass 1
13.
O.
2
3
4
5
6
13.
TOTAL
PREY : CLUPEA HARENGUS
Age dass 1
2
58.
3
4
5
6
58.
TOTAL
4
102
0.08
71.53
5
30
0.13
77.98
48
0.15
95.68
21120.
67428.
190.
46.
375.
3812.
101.
4288.
165.
3410.
57.
3632.
1008.
5160.
153.
6322.
3140.
2319.
5030.
134.
45.
7528.
5532.
10019.
110.
12.
15673.
3859.
4563.
80.
19.
8522.
1901.
2462.
479.
116.
4450.
5215.
955.
218.
2688.
6836.
2238.
564.
1.
190.
787.
8.
46.
3025.
115.
1.
65607
6t
71388.
795.
4958.
10837.
12326.
2015.
3318.
1333.
706.
23.
11.
7407.
294.
10.
O.
O.
3219.
779.
45.
2.
304.
4046.
1246.
912.
131.
14.
57.
2362.
2662.
171.
88.
12.
47.
2982.
796.
337.
204.
27.
112.
1478.
9.
649.
20.
1.
1.
1600.
1438.
134.
26.
5542.
2181.
265.
128.
92.
8234.
6.
4118.
4595.
964.
508.
367.
10559.
5.
5595.
2668.
376.
176.
126.
8946.
O.
O.
O.
679.
3174.
1.
1.
5.
2.
O.
1.
4.
1.
O.
O.
9.
0.6.
140.
478.
11.
135.
356.
8.
O.
O.
O.
O.
32.
3.
632.
22.
521.
200.
233.
50.
51.
116.
116.
1035.
3947.
5229.
33936.
20383.
38599.
PREY: CLUPEA SPRATTUS
Age dass 1
1.
2
3
4
5
6
TOTAL
1.
PREY:OTHER
All classes
74
0.05
48.49
ALL AREAS
6937.
PREY: MELANOGRAMMUS AEGLEFINUS
Age dass 1
379.
45.
2
1.
O.
3
4
45.
380.
TOTAL
PREY: AMMODYTIDAE
Age dass 1
2
3
4
.6
TOTAL
3
O.
PREY: TRlS0PTERUS ESMARKI
Age dass 1
4.
O.
2
3
4
5
4.
TOTAL
•
QUARTER: 1
13.
19.
O.
O.
6.
2.
O.
O.
9.
18.
15.
23
Table 1.3.6
Average stornach content weight (g) per 1000 fish by age class of commercially exploited prey species
by predator age class, area and quarter.
PREDATOR : COD
AGECLASS
YEAR: 1987
0
2
Nr of stomachs with food 2
% empty stomaehs
0.00
Mean length
7.35
1423
0.15
28.24
PREY:ALL SPECIES
All classes
169.
3723.
PREY:GADUS MORHUA
Age class 0
1
2
TOTAL
•
-
ALL AREAS
QUARTER: 3
1371
0.14
39.74
12616.
3
34
0.17
63.19
53263.
4
76
0.14
71.29
90247.
5
24
0.10
83.58
6+
15
0.06
91.74
147930.
235412.
3.
O.
O.
3.
160.
314.
475.
4715.
3292.
8007.
2979.
2392.
5371.
1272.
19396.
20668.
PREY: MELANOGRAMMUS AEGLEFINUS
Age class 0
12.
253.
1.
130.
1
O.
2
3
4
384.
13.
TOTAL
769.
4990.
630.
85.
6.
6480.
257.
8351.
2326.
317.
23.
1274.
76.
7968.
2300.
315.
23.
10683.
27.
3923.
9399.
518.
932.
14798.
PREY: MERLANGIUS MERLANGUS
Age class 0
57.
15.
1
O.
2
3
4
5
TOTAL
73.
568.
30.
1984.
2191.
331.
112.
20.
4669.
258.
5651.
7015.
1322.
386.
68.
14700.
391.
7578.
12147.
3815.
1423.
250.
25604.
517.
4242.
5908.
2052.
787.
139.
13645.
PREY:TR1S0PTERUS ESMARKI
Age class 0
29.
1
15.
O.
2
3
44.
TOTAL
396.
437.
16.
4.
853.
2383.
4008.
64.
4.
6459.
2260.
5939.
391.
95.
8685.
3962.
12159.
318.
23.
16463.
2093.
6512.
135.
1.
1207.
968.
137.
31.
7.
2349.
256.
2711.
1239.
38.
4.
4248.
641.
6036.
2980.
491.
105.
10253.
345.
2704.
1741.
473.
105.
5367.
2669.
7187.
5181.
1991.
442.
17469.
703.
441.
258.
2.
800.
441.
716.
22..
5.
1.
1986.
4214.
5983.
3827.
888.
153.
2.
15068.
PREY: CLUPEA HARENGUS
Age class 0
3.
1
152.
2
56.
3
1.
4
O.
5
213.
TOTAL
PREY: CLUPEA SPRATTUS
O.
Age c1ass 0
1
O.
2
2.
O.
3
2.
TOTAL
PREY: AMMODYTIDAE
Age class 0
1
2
3
4
5
TOTAL
PREY:OTHER
All classes
169.
300.
237.
31.
O.
O.
O.
O.
13.
11.
O.
O.
13.
12.
83.
22.
46.
3.
1.
O.
O.
O.
308.
449.
211.
466.
47.
9.
1.
1183.
154.
1404.
3070.
7263.
30767.
359i3.
167.
54.
82.
3.
1.
O.
82457.
8741.
145024.
26
Table 2.1.1
Number of stomaehs sampled by size dass of whltlng. arca and quarter in 1985.
Size dass
70
80 100
150
200 250
300 350
400 500 600 700
800 1000
Total
Quarter 1
-_ .... _------------------_ .._------_.. _-_ ..__ ........._- ...-------- .....-----_ ..._-------_ .. _-_ .. _-_ .. _-------- .. _-------..._----------------------------------Area 1
Area2
Area3
Area4
Area5
Area 6
Area 7
Total
2
2
116
182
318
129
59
196
84
84
255
371
149
97
356
82
311 380
294 174
342 259
148 138
138 128
387 227
71
54
294 203
46
6
132 26
56
4
58
36
16
77
24
49
56
1084 1394 1691 1360
712 315
91
1
1445
957
1449
624
536
1262
377
1
6650
20
1
13
Quarter 3
---- ...-------_ ..._---------------------------------------- .. _--------------------------------------------------_...
Area 1
Area2
Area3
Area4
Area5
Area6
Area 7
49
3
120
Total
253
43
38
333
193
197
91
30
212
57
159
20
36
3
7
61
3
31
8
6
733 1805 1883 1113
289
67
19
248
94
6
250
116
121
372
414
241
40
475
142
310
402
294
226
40
459
152
1
1004
1017
1315
655
123
1518
512
1
6144
18
4
Table 2.1.2
Number of stomaehs sampled by size dass of whlting. area and quarter in 1986.
Size dass
70
80 100
150
200 250
300 350
400 500 600 700
800 1000
Total
Quarter 1
---------------------------------------------------------------_ ... _-- ..._------------------------.. _-----1073
72
77 310 310 247
41
16
Area 1
556
996
63
Area2
Area3
Area4
Area5
Area6
Area 7
258
247
8
233
301
16
47
177
10
16
163
24
2
82
5
26
253
10
270
20
180
137
10
48
10
1
17
899
57
Total
848
917
741
660
384
77
17
3644
Quarter 3
-------------------------------------------_ .._---------------------------------------------------------
Area 1
Area2
Area3
Area4
Area5
Area6
Area 7
179
37
122
Total
338
3
79
130
39
81 369
129 182
208 171
72
71
380
76
192
6
11
3
65
1269
509
713
221
242
489
572 212
65
2712
794
71
45
27
Table 2.2.1
Summary of stomaeh contents by predator by age class. area and quarter.
YEAR: 1985
PREDATOR: WHITING
AGECLASS
0
GENERAL RESULTS
Nr of st. sampled
Nr of st. with food
Nr of regurgit. st.
Ne of ernpty st.
% empty stomaehs
Mean length
Total wght all prey
Total ne of prey
Average prey weght
WElGiIT % BY MAJOR TAXA
RHYNCHOCOELA
AN!\'EUlDA
GASlROPODA
BlVALVIA
CEPHALOPODA
CRUSTACEA
MYSIDA
FLABEll1FERA
GAMMARIDEA
HYPERllDEA
EUPHAUSIACEA
CARlDEA
ASTACIDEA
ANOMURA
BRACHYRHYNCHA
OTHER CRUST...)
EOIIURA
PRIAPULIDA
UROGIORDATA
GNATHOSTOMATA
OTHERS·)
tJ!\'KNOWN
WElGHT % COMMERCIAL SPEC.
G. morhua
M. aeglef"mus
M. merlangus
T. esmarkii
C. harengus
S. sprauus
AMMODYlIDAE
N. norvegieus
C. crangon
QUARTER: 1
2
3
ALL AREAS
4
5
6+
2386
1100
947
339
14.208
2600
1096
1074
428
16.462
871
374
333
163
18.714
463
210
169
85
18.359
156
74
54
28
17.949
174
83
58
32
18.391
0.411
10.385
0.040
1.847
4.260
0.434
3.663
2.237
1.638
5.110
1.774
2.880
5.650
1.780
3.174
5.442
1.827
2.978
0.15
18.27
0.22
3.11
1.87
30.69
0.53
0.09
1.01
1.49
7.62
13.78
0.23
3.16
0.14
0.12
3.21
0.06
0.26
41.73
0.18
0.26
0.32
7.63
0.03
3.86
2.82
6.56
0.10
0.22
0.24
0.12
0.28
3.96
0.06
0.87
0.04
0.03
0.96
0.31
0.06
77.11
0.05
0.30
0.08
2.33
0.04
1.49
1.13
3.37
0.02
0.17
0.04
0.02
0.11
2.22
0.09
0.27
0.05
0.01
0.30
0.09
0.01
91.00
0.00
0.15
0.02
1.47
0.02
0.53
0.53
3.09
0.01
0.20
0.02
0.00
0.04
2.43
0.04
0.11
0.02
0.00
0.20
0.03
0.00
94.02
0.01
1.20
0.01
0.34
0.38
3.06
0.01
0.21
0.03
0.00
0.03
2.43
0.02
0.09
0.01
0.00
0.18
0.02
0.00
94.72
0.09
0.08
0.01
1.22
0.01
0.39
0.42
3.18
0.01
0.22
0.03
0.00
0.03
2.45
0.03
0.09
0.02
0.00
0.17
0.02
0.00
94.50
0.00
0.07
0.35
5.83
0.12
15.40
6.66
0.23
2.05
0.00
1.30
3.15
28.89
5.36
13.40
5.74
0.06
0.38
0.01
3.12
3.18
38.88
9.73
15.68
4.37
0.09
0.22
0.09
4.10
3.26
41.45
8.49
17.53
6.16
0.04
0.17
0.39
4.25
4.53
41.28
8.20
18.53
6.22
0.02
0.22
0.63
3.82
5.49
40.89
8.29
18.47
5.35
0.03
0.29
.) Include CNlDARlA. ECHlNODERMATA. CliAETOGNATHA
..) Include CALANOIDA. CUMACEA. CAPRELUDEA. CANCRIDEA
28
Table 2.2.2
Summary of stomach contents by predator by age dass. area and quarter.
PREDATOR: WHITING
AGECLASS
GENERALRESULTS
Nr of sL sampled
Nr of st. with food
Nr of regurgit. st.
Nr of empty SL
% empty stomaehs
Mean length
Total wght a11 peey
Total nr oe peey
Average peey wght
YEAR: 1985
0
QUARTER: 3
2
3
270
118
135
17
6.296
1986
704
1139
144
7.251
2933
1047
1705
182
6.205
526
179
324
24
4.563
0.131
14.341
0.009
1.750
21.343
0.082
2.930
18.060
0.162
WElGlIT % BY MAJOR TAXA
CNlDARIA
RllYNOIOCOELA
0.46
ANNEIllDA
0.12
BIVALVJA
20.82
CRUSTACEA
CALANOIDA
2.02
MYSIDA
0.16
0.08
HYPERllDEA
EUPHAUSIACEA
0.03
CARIDEA
1.75
ANOMURA
11.19
CANCRIDEA
0.10
BRACHYRHYNCHA
OTHER CRUST. **)
0.00
0.86
ECHlNODERMATA
OIAETOONAlliA
77.71
GNATHOSTOMATA
0.00
OTIlERS*)
0.03
UNKNOWN
0.26
1.00
6.68
3.14
18.48
0.48
0.03
0.61
0.50
1.79
6.76
0.40
1.58
0.12
1.06
0.82
68.42
0.08
0.05
WEIGHT % COMMERCIAL SPEC.
G. rnorhua
M. aeglefmus
5.98
M. meriangus
39.79
T. esmarkii
2.25
0.00
C. harengus
4.95
S sprallus
12.10
AMMODYIIDAE
0.00
S. scomber
0.28
C. crangon
0.21
1.92
8.36
0.42
3.42
6.49
22.32
0.13
0.59
ALL AREAS
4
6t-
182
12
4.082
67
22
43
2
2.985
92
32
57
4
4.348
4.956
27.254
0.182
5.841
29.474
0.198
8.971
38.930
0.230
10.176
35.619
0.286
0.07
6.38
6.24
1.46
11.71
0.17
0.01
0.36
0.38
0.81
4.89
0.53
1.21
0.06
0.29
0.41
73.36
0.06
0.02
0.00
4.15
8.48
0.39
8.25
0.06
0.00
0.19
0.30
0.54
3.28
1.08
0.80
0.03
0.01
0.26
78.33
0.13
0.01
3.66
8.06
0.26
7.31
0.05
0.00
0.15
0.26
0.45
2.80
1.18
0.73
0.03
0.01
0.23
80.34
0.12
0.01
1.71
7.86
0.03
5.68
0.04
0.00
0.09
0.20
0.28
1.84
1.39
0.76
0.02
0.00
0.17
84.42
0.12
0.00
2.20
6.74
0.14
85.84
0.09
0.00
0.19
5.79
5.67
1.71
9.50
6.89
14.44
0.10
0.36
0.10
8.54
4.54
4.28
17.84
5.39
9.58
0.23
0.33
0.07
8.00
4.49
7.09
20.76
4.58
8.71
0.22
0.29
0.03
7.15
3.60
11.27
28.60
3.38
6.09
0.22
0.23
0.02
6.16
3.67
13.80
30.24
2.81
5.80
0.18
0.18
*) lnclude GASTROPODA. CEPHALOPODA, SIPUNCULA. ECHIURA. UROCHORDATA
*.) lnclude CUMACEA. FLABELLIFERA. GAMMARIDEA. OXYRHYNCHA
294
5
99
4.99
0.03
0.00
0.06
0.16
0.22
1.54
1.36
0.74
0.02
29
Table 2.2.3
Summary of s10mach contents by preda10r by ge dass, area and quarter.
YEAR: 1986
PREDATOR: WHITING
AGECLASS
0
GENERAL RESULTS
Nr of sL sampled
Nr of s1. wilh food
Nr of regurgiL s1.
Nr of emp1y stomaehs
% emp1y s10machs
Mean lenglh
Total wght all prey
T01al nr of prey
Average prey wght
QUARTER: 1
2
1781
473
1247
60
3.369
849
135
666
47
5.536
717
107
568
42
5.858
0.869
3.702
0.235
3.192
1.665
1.917
4.932
1.710
2.884
WElGlIT % BY MAJOR TAXA
PHAEOPHYrA
ANNELlIDA
GASIROPODA
BIVALVIA
CEPHALOPODA
CRUSTACEA
MYSIDA
FLABEUIFERA
GAMMARIDEA
HYPERllDEA
EUPHAUSIACEA
CARIDEA
ANOMURA
OXYRHYNCHA
BRACHYRHYNCHA
GNATHOSTOMATA
OTHERS·)
UNKNOWN
4.62
0.05
0.00
1.88
0.32
6.49
30.76
0.04
0.08
0.15
1.28
3.25
22.08
2.28
0.00
0.14
57.46
0.02
0.41
WElGHT % COMMERCIAL SPEC.
G. mohua
M. aeglef"mus
M. merlangus
T. esmarkü
C. harengus
S • sprattus
AMMODYTIDAE
C. crangon
0.48
0.31
11.08
4.99
4.56
0.86
27.69
1.77
.) Include CNlDARIA, ECmURA
3
ALL AREAS
4
211
32
169
5
6t
5.213
52
8
42
2
3.846
33
5
26
1
3.030
6.086
1.820
3.345
7.053
1.916
3.682
8.718
2.068
4.215
0.11
1.06
0.06
0.01
2.33
3.53
0.15
0.52
0.02
0.00
0.94
3.47
0.32
0.06
0.00
0.02
2.57
0.27
0.06
0.01
92.91
0.00
0.30
0.03
0.00
0.01
2.90
0.11
0.01
0.00
94.90
0.00
0.06
2.39
5.78
49.72
0.85
0.37
7.69
0.00
0.06
1.02
5.33
53.40
0.46
0.10
5.38
0.00
11
6.79.
5.09
0.00
0.01
0.08
0.01
0.19
3.32
0.54
0.10
0.02
85.81
0.00
0.02
0.01
2.16
0.19
0.20
5.66
3.50
0.00
0.16
0.10
0.01
0.07
1.83
0.61
0.15
0.02
88.45
0.01
0.00
0.07
1.52
0.11
0.09
3.61
3.50
0.00
0.28
0.07
0.00
0.04
2.24
0.41
0.09
0.01
91.18
0.00
0.00
1.16
4.74
8.40
21.56
5.15
1.67
14.45
0.56
0.18
5.63
7.21
35.00
2.07
1.13
11.38
0.08
0.08
3.67
6.25
44.74
1.24
0.65
9.29
0.02
30
Table 2.2.4
Summary of stomaeh conlenlS by predator by predator age class, area and quarter.
YEAR: 1985
PREDATOR : WHITING
AGECLASS
GENERAL RESULTS
Nr of sL sampled
Nr of st. with food
Nr of regurgiL st.
Nr of empty sL
% empty stomachs
Mean length
Total wght al1 prey
Total nr of prey
Average prey wght
0
348
176
171
1
0.287
0.315
1.302
0.242
WEIGlIT % BY MAJOR TAXA
PHAEOPHYTA
0.55
ANNElllDA
GASTROPODA
0.43
CEPHALOPODA
CRUSTACEA
3.03
0.02
GAMMARIDEA
0.18
HYPERllDEA
EUPHAUSIACEA
1.18
CARIDEA
0.20
ANOMURA
1.40
BRACHYRHYNCHA
GNATHOSTOMATAI
95.97
UNKNOWN
0.02
WEIGHT % COMMERCIAL SPEC.
G. morhua
M. aeglefinus
5.90
M. merlangus
0.33
T. esmarkü
0.57
C. harengus
2.96
S.sprauus
AMMODYTIDAE
24.09
QUARTER: 3
2
811
289
511
3
1.356
477
136
341
1
0.210
838
222
613
1
0.119
2.167
5.495
0.394
3.483
8.539
0.408
4.792
8.249
0.581
11
0.00
1.58
0.04
0.69
3.79
0.21
0.71
2.32
0.35
0.10
0.10
93.87
0.03
0.04
0.60
0.27
0.37
2.33
0.13
0.57
0.77
0.41
0.04
0.42
96.39
0.00
0.13
0.19
0.53
0.17
1.55
0.09
0.38
0.33
0.37
0.05
0.34
97.44
0.00
0.41
1.29
5.17
14.59
12.99
0.14
5.21
10.19
27.12
14.78
2.25
23.55
0.03
7.05
8.32
39.83
13.73
0.78
14.66
49.09
ALL AREAS
4
5
6t
165
42
123
0
0.0
53
13
39
0
0.0
19
4
14
0
0.0
7.386
5.642
1.309
8.540
2.966
2.879
7.674
5.563
1.379
0.13
0.15
0.48
0.05
0.85
0.07
0.15
0.09
0.20
0.22
0.13
98.33
0.20
0.10
0.66
0.01
0.49
0.10
0.05
0.01
0.16
0.15
0.02
98.55
0.12
0.08
0.45
0.04
0.75
0.12
0.14
0.09
0.19
0.09
0.13
98.55
6.01
4.41
58.87
11.10
0.16
7.42
6.65
1.95
64.15
9.94
5.36
3.65
59.30
8.78
5.89
7.38
31
Table 2.3.1 .
Average sIamach conlenl weight (g) per 1000 fish by age dass of commercially exploited prey species
by predator age dass, area and quarter.
YEAR: 1985
PREDATOR: WHITING
AGECLASS
0
Nr of sL with food
% emply stomachs
Mean length
0
0.00
0.00
PREY : ALL SPEClES
All dasses
QUARTER: 1
2
3
4
990
0.13
15.38
1220
0.17
22.99
379
0.19
28.48
199
0.18
32.40
415.
1715.
PREY:GADUS MORHUA
Age class 1
TOTAL
PREY: MELANOGRAMMUS AEGLEFINUS
Age dass 1
16.
2
O.
17.
TOTAL
PREY : MERLANGIUS MERLANGUS
Age class 1
1.
2
3
TOTAL
1.
PREY : TRISOPTERUS ESMARKI
Age dass 0
14.
1
O.
2
3
O.
4
O.
TOTAL
14.
PREY: CLUPEA HARENGUS
Age dass 1
O.
2
O.
3
4
TOTAL
O.
PREY: CLUPEA SPRATTUS
Age dass 1
44.
2
24.
3
1.
O.
4
5
O.
O.
6
69.
TOTAL
PREY:AMMODYTlDAE
Age dass 1
2
3
4
TOTAL
PREY:OTHER
All classes
ALL AREAS
26.
8.
O.
O.
78
0.17
34.83
5287.
5718.
5697.
O.
O.
1.
1.
3.
3.
10.
10.
158.
l.
158.
132.
169.
O.
O.
133.
169.
221.
1.
222.
79.
48.
l.
127.
95.
195.
3.
293.
146.
286.
5.
436.
110.
6.
72.
116.
O.
1.
1489.
513.
11.
O.
O.
O.
O.
2622.
912.
14.
1.
3549.
2123.
799.
8.
O.
O.
252.
16.
416.
30.
O.
O.
324.
2015.
2221.
725.
12.
1.
2959.
1.
69.
1.
238.
5.
l.
306.
14.
O.
O.
71
0.15
34.46
6t
4004.
71.
1.
251.
71.
1.
5
O.
2931.
O.
O.
O.
O.
70.
244.
321.
269.
447.
93.
163.
35.
5.
I.
108.
259.
70.
12.
2.
34.
167.
63.
12.
3.
1.
279.
77.
337.
139.
28.
7.
2.
590.
284.
246.
25.
181.
159.
15.
O.
O.
297.
451.
42.
421.
117.
23.
6.
2.
612.
52.
44.
4.
143.
65.
4.
251.
198.
19.
O.
O.
O.
O.
O.
34.
99.
212.
468.
555.
355.
295.
835.
809.
667.
600.
706.
32
Table 2.3.2
Average stornach content weight (g) per 1000 fish by age dass of commercially exploited prey species
by predator age dass. area and quaner.
YEAR: 1985
PREDATOR: WHITING
AGECLASS
0
QUARTER: 3
ALL AREAS
2
3
4
687
434
0.05
30.67
280
173
0.05
32.52
5
Nr of stomachs sampled254
Nr of regurgit. sI.
135
% empty sto.
0.06
Mean length
5.39
2162
1301
0.07
21.82
2586
1417
0.07
25.92
PREY:ALL SPECIES
All dasses
161.
1773.
2604.
5461.
7878.
12077.
5.
5.
3.
3.
5.
5.
1.
530.
PREY:GADUS MORHUA
Age dass 0
lDTAL
3.
3.
85
58
0.02
34.81
6t
96
62
0.02
35.49
13201.
1.
PREY: MELANOGRAMMUS AEGLEFINUS
82.
Age dass 0
10.
59.
O.
1
82.
10.
59.
lDTAL
658.
1715.
O.
O.
O.
O.
530.
658.
1716.
1411.
PREY : MERLANGIUS MERLANGUS
58.
172.
Age dass 0
58.
172.
lDTAL
60.
60.
309.
309.
360.
360.
477.
477.
365.
365.
4.
8.
64.
427.
28.
103.
1032.
58.
232.
2397.
130.
174.
2415.
128.
PREY: TRISOPTERUS ESMARKI
Age dass 0
O.
10.
1
2
3
O.
10.
TOTAL
O.
O.
1410.
O.
O.
o.
13.
519.
1193.
2758.
2717.
32.
30.
1018.
464.
11.
1870.
981.
26.
1675.
1432.
O.
PREY: CLUPEA HARENGUS
Age c1ass 0
3.
49.
1
2
4
lDTAL
52.
15.
222.
42.
730.
185.
O.
O.
279.
947.
1513.
2863.
3133.
PREY: CLUPEA SPRATTUS
Age dass 0
87.
11.
1
1.
23.
2
3
1.
112.
lDTAL
11.
134.
2.
75.
2.
213.
140.
4.
115.
4.
263.
109.
4.
114.
4.
230.
262.
8.
236.
8.
513.
246.
7.
204.
7.
462.
288.
47.
24.
1.
176.
73.
45.
11.
1.
1.
361.
307.
201.
138.
71.
28.
2.
1.
1.
444.
222.
191.
96.
29.
3.
2.
1.
544.
331.
303.
70.
18.
2.
1.
1.
725.
359.
535.
157.
46.
4.
2.
1.
1104.
1003.
1646.
2446.
3375.
3024.
4010.
PREY: AMMODYTIDAE
Age c1ass 0
26.
O.
1
2
3
4
5
6
26.
TOTAL
PREY:OTHER
All dasses
57.
O.
O.
33
Table 2.3.3
Average stomach content weight (g) per 1000 fish by age class of commercially exploited prey species
by predalor age class, area and quarter.
PREDATOR: WHITING
AGECLASS
QUARTER: 1
YEAR: 1986
o
2
146
0.04
23.34
3
4
29
0.05
29.98
5
455
0.04
14.81
PREY : ALL SPECIES
All classes
694.
2833.
4659.
7165.
8147.
8993.
16.
16.
52.
52.
17.
17.
6.
6.
4.
4.
3.
3.
PREY: MELANOGRAMMUS AEGLEFINUS
Age class 1
4.
31.
lDTAL
4.
31.
197.
197.
243.
243.
84.
84.
98.
98.
PREY: MERLANGIUS MERLANGUS
Age class 1
71.
lDTAL
71.
530.
530.
397.
397.
448.
448.
505.
505.
1218.
105.
20.
1.
1344.
3451.
348.
21.
1.
3821.
4198.
484.
34.
1.
4717.
4761.
745.
67.
17.
184.
3.'
54.
82.
PREY: TR1S0PTERUS ESMARKI
8.
Age class 0
1
2
3
2.
O.
359.
359.
4
0.00
31.23
O.
225.
6.
1.
O.
4
8
0.02
31.42
6t
Nr of stomaehs with food 0
% empty stomaehs
0.00
Mean length
0.00
PREY: GADUS MORHUA
Age class 1
roTAL
114
0.06
26.20
ALL AREAS
2.
5575.
11.
233.
PREY : CLUPEA HARENGUS
6.
Age class 1
32.
2
O.
3
38.
roTAL
104.
141.
1.
246.
O.
O.
O.
202.
57.
83.
72.
81.
8.
O.
8.
1.
11.
1.
15.
1.
O.
O.
80.
90.
13.
16.
394.
48.
442.
372.
48.
419.
189.
28.
218.
276.
30.
306.
1837.
2208.
2577.
2503.
lDTAL
PREY: CLUPEA SPRATTUS
3.
Age class 1
9.
2
1.
3
4
13.
lDTAL
PREY: AMMODYTIDAE
Age class 1
213.
8.
lDTAL
221.
367.
13.
381.
PREY:OTHER
All classes
320.
1451.
2
2.
2.
O.
2.
34
Table 2.3.4
Average stomach content weight (g) per 1000 fish by age class of commercially exploited prey speciesby predator age class. area
and quarter.
YEAR: 1986
PREDATOR: WHITING
AGECLASS
Nr of sl. with food
% empty stomaehs
Mean length
0
171
0.00
0.94
PREY:ALL SPECIES
All c1asses
21.
282
0.02
10.75
1147.
QUARTER: 3
2
3
217
0.00
9.86
160
0.00
7.76
1763.
1658.
O.
O.
ALL AREAS
4
34
0.00
26.66
5
8
0.00
24.81
6+
7
0.00
21.71
7074.
6079.
7110.
84.
185.
216.
1546.
O.
O.
O.
O.
84.
185.
216.
1546.
171.
51.
O.
171.
51.
120.
2.
121.
122.
4.
126.
704.
O.
176.
45.
467.
210.
1893.
1719.
26.
3639.
2464.
1053.
16.
3533.
403.
403.
PREY:GADUS MORHUA
1UI'AL
1.
PREY: MELANOGRAMMUS AEGLEFINUS
Age class 0
3.
17.
71.
O.
O.
1
1UI'AL
3.
17.
71.
PREY : MERLANGlUS MERLANGUS
Age class 0
O.
46.
1
O.
46.
1UI'AL
PREY: TRISOPTERUS ESMARKI
Age class 0
4.
155.
1
3.
2
4.
158.
1UI'AL
704.
O.
O.
221.
678.
2495.
2190.
24.
4709.
PREY : CLUPEA HARENGUS
Age class 0
2
27.
161.
1
2.
188.
1UI'AL
33.
585.
618.
19.
391.
410.
17.
778.
796.
50.
929.
979.
PREY: CLUPEA SPRATTUS
Age class 0
7.
1UI'AL
7.
2.
2.
O.
O.
275.
223.
12.
4.
152.
118.
7.
2.
322.
137.
8.
2.
316.
1.
243.
PREY: AMMODYTIDAE
Age class 0
3.
1
O.
2
3
4
3.
1UI'AL
PREY:OTHER
8.
All classes
448.
26.
1.
O.
O.
O.
O.
O.
475.
514.
278.
469.
317.
243.
254.
167.
157.
793.
802.
683.
35
Table 2.4.1
Average prey weight at time of ingestion (g) by age class of commercially exploited prey speeiesby predator age class, nad quarter.
YEAR : 1981/85/86
PREDATOR: WHITING
AGECLASS
0
QUARTER: 1
ALL AREAS
2
3
4
5
6+
PREY: ALL SPECIES
All classes
0.20
1.43
2.10
2.97
3.82
4.24
PREY:GADUS MORHUA
Age class 1
7.89
17.52
17.58
17.50
25.45
87.759
PREY: MELANOGRAMMUS AEGLEFINUS
5.85
Age class 1
19.45
2
36.00
20.73
3
26.09
35.10
24.13
38.82
18.95
39.71
18.85
41.37
PREY: MERLANGlUS MERLANGUS
9.12
Age class 1
2
3
24.05
51.50
23.79
80.88
32.57
96.15
120.00
33.44
106.60
120.00
43.72
111.10
125.00
PREY: TRISOPTERUS ESMARKI
1.44
Age class 0
4.69
1
10.76
2
3
4
0.02
10.30
20.22
24.32
0.23
13.27
19.80
36.63
33.33
15.06
20.81
39.12
80.00
15.66
21.39
41.02
57.14
16.39
22.04
43.86
44.44
8.02
9.09
7.37
14.55
34.48
5.85
20.18
65.12
11.57
23.42
57.14
4.22
30.75
64.52
1.83
6.53
13.15
12.07
25.00
1.72
7.01
15.03
16.83
23.53
1.82
6.93
12.03
13.13
35.29
57.14
1.73
7.18
11.87
12.59
27.27
66.67
1.96
6.94
14.43
16.52
37.84
1.78
5.80
2.79
8.72
20.14
20.00
26.00
28.00
5.99
8.26
24.44
36.71
41.75
40.00
5.57
9.65
18.61
36.88
40.09
39.92
5.78
10.16
19.53
38.29
40.05
40.37
5.19
8.87
20.28
38.55
39.55
40.24
0.12
0.65
0.78
0.86
1.14
1.23
PREY: CLUPEA HARENGUS
4.41
Age class 1
6.65
2
3
PREY: CLUl'EA SI'RATTUS
Age class 1
1.34
5.01
2
10.26
3
10.00
4
5
6
PREY: AMMODYTIDAE
Age class 1
2
3
4
5
6
PREY:OTHER
All classes
9.71
36
Table 2.4.2
Average prey weight at time of ingestion (g) by age class of commercially exploited prey speciesby predator age class, nad quarter.
YEAR : 1981185186
PREDATOR: WHITING
AGECl.ASS
0
ALL AREAS
QUARTER: 3
2
3
4
5
6t
2.88
PREY:ALL SPECIES
All classes
0.02
0.36
0.56
0.73
1.02
2.87
PREY:GADUS MORHUA
Age class 0
4.17
6.77
7.28
8.77
12.50
PREY: MELANOGRAMMUS AEGLEFINUS
4.85
Age class 0
4.24
6.64
1
15.93
5.10
15.74
5.60
15.73
6.62
14.90
4.00
4.00
4.00
57.14
4.00
53.33
PREY : TRISOPTERUS ESMARKI
Age class 0
2.02
2.57
1
10.17
2
2.34
16.76
20.00
2.63
29.77
31.77
5.51
30.33
35.47
5.51
32.12
35.92
5.80
30.96
37.78
PREY: CLUPEA HARENGUS
Age class 0
3.20
6.36
1
12.09
2
9.56
7.55
14.53
9.69
11.55
25.78
8.40
17.76
51.27
9.73
21.98
50.29
7.09
20.22
52.95
PREY: CLUPEA SPRATTUS
Age class 0
4.28
9.50
10.00
1
10.00
2
10.10
3
8.23
12.16
14.71
13.32
7.24
13.58
17.76
18.39
6.63
14.64
16.79
16.98
5.92
14.64
17.34
17.23
6.30
14.76
17.87
17.87
1.82
11.89
12.00
15.00
18.00
1.99
14.95
12.54
19.94
18.66
66.67
1.83
17.98
16.25
18.83
18.40
20.00
40.00
1.98
17.69
14.92
22.66
22.90
36.36
33.33
1.96
26.68
19.51
24.86
25.54
28.57
50.00
1.79
28.81
21.35
25.75
23.57
23.53
20.00
0.17
0.19
0.28
0.32
1.36
1.10
PREY: MERLANGIUS MERLANGUS
Age class 0
4.10
4.88
1
PREY: AMMODYTIDAE
1.00
Age class 0
1
2
3
4
5
6
PREY: OTHER
0.01
All classes
6.90
14.34
0.837
37
Table 3.1
Summary of stomach contents by predator by age class, area and quarter.
PREDATOR: SAITHE
AGECLASS
GENERALRESULTS
Nr of sL sarnpled
Nr of st. with food
Nr of regurgiL st.
Nr of ernpty sL
% empty stomaehs
Mean length
Total wght all prey
YEAR: 1985
3
193
118
53
4
QUARTER: 3
5
6
ALL AREAS
7
281
145
101
36
12.746
30
16
11
4
12.533
73
11.378
1500
885
439
176
11.717
8.152
9.061
15.413
32.77
30.95
1.82
67.23
0.08
8.85
0.63
38.12
22
WElGlIT % BY MAJOR TAXA
Crustacea
35.78
34.48
Euphausiacea
Caridea
1.30
Gnathostomata
64.22
WElGHT % COMMERCIAL SPEC.
G. momua
0.01
M. aeglefinus
9.73
M. merlangus
0.67
T. esmarkii
32.51
• C. harengus
11.16
AMMODYlIDAE
Pandalus spec.
1.30
9.35
1.82
8
9+
8
10.314
11
7
3
1
10.323
14
9
4
1
7.329
17.469
61.093
60.418
77.987
21.77
17.85
3.92
78.23
19.74
15.57
4.17
80.26
5.78
2.19
3.59
94.22
5.84
2.25
3.59
94.16
4.94
2.59
2.35
94.06
0.36
7.66
0.34
57.56
0.03
1.41
3.92
0.38
7.60
0.29
58.82
1.64
0.36
4.17
0.00
5.61
0.00
36.42
35.92
1.69
3.59
0.00
5.62
0.00
36.52
35.77
1.69
3.59
3.67
19.18
23.78
37.76
1.11
2.35
46
20
38
Table 3.2
Average stornach content weight (g) per 1000 fish by age cIass of commercially exploited prey species by
predator age cIass, area and quarter.
Predator: SAITHE
3
4
5
193
0.11
1500
0.12
281
0.13
Age class
Nr of st. with food
% empty stomaehs
Prey: ALL SPECIES
All classes
8152
Total North Sea
Quarter: 3
Year: 1986
6
30
0.13
9061
15413
17469
7
56
67
Prey: Melanogrammus aeglefinus
802
Age class: 0
793
I
1181
1328
Prey: Gadus morhua
Age class: 0
793
'IDTAL
Prey: Merlanglus mcrlangus
Age class: 0
55
1
802
1181
1328
57
53
50
7
73
0.10
61093
8
11
0.10
60418
3425
3
3428
3392
Prey: Trlsopterus esmarkll
Age class: 0
2079
557
I
14
2
2650
'IDTAL
2
3395
2861
2
2
4788
16486
973
22247
4761
16339
963
22063
3979
13752
814
18545
10
144
54
753
11032
4164
751
10863
4100
1195
17951
5267
1
4
78
286
5988
21947
5896
21610
5032
29445
215
62
939
81
1020
800
12327
11312
53
50
2235
11780
39
3454
2893
5753
226
8872
3026
6970
280
10276
2
1
Prey: Clupea harengus
Age class: 2
'IDTAL
Prey: Ammodytldae
Age class: 0
1
'IDTAL
2859
758
9791
3798
480
130
14957
57
3
4
5
6
77987
3
2
55
14
0.07
2
3
4
5
6
'IDTAL
9+
894
16
910
833
14
847
3
1
218
63
952
82
1034
3743
3892
5029
5398
12435
69
869
Pley: OTHER
All classes
39
Table 3.3
Average prey weight (g) at time of ingestion by age class of commercia11y exploited prey species by predator age
dass, area and quarter.
Predator: SAITHE
Ycar: 1986
Total North Sea
Quarter: 3
4
5
6
7
8
9+
5.00
5.00
5.00
5.00
5.00
5.00
Prey: Melanograrnrnus aeglefinus
Age dass: 0
5/78
1
5.62
4.90
4.96
8.58
15.88
8.56
15.88
Prey: Merlangius rncrlangus
Age dass: 0
3.01
1
3.19
3.84
3.92
3.92
3.92
Age dass
3
Prey: Gadus morhua
Age dass: 0
2+
269.67
Prey: Trlsoptcrus esrnarkil
Age dass: 0
2.54
12.55
1
2
25.00
3.33
13.07
25.00
Prey: Clupea harengus
Age dass: 2
3
4
5
6
Prey: Ammodytldae
Age dass: 0
1
8.33
15.88
2.34
5.93
1.98
5.93
6.54
14.78
25.00
7.01
15.09
25.00
7.86
17.44
25.00
7.85
17.43
25.00
7.61
16.90
25.00
109.00
185.80
71.15
109.00
185.80
71.15
109.00
185.80
71.15
109.00
185.80
71.15
109.00
1185.80
237.24
237.24
237.24
237.24
237.24
0.65
5.93
0.72
5.93
5.90
5.93
5.88
5.93
5.74
5.74
40
Table 4.1
Age Length Key applied to sprats in the third quarter of 1985,1986 and 1987
o
Age class
Size dass
<=70
80
100
150
1
2
3
4
5
100.0
3.0
94.0
3.0
79.5
19.6
0.9
4
5
6+
100.0
Table 4.2
Age Length Keys applied to sandeeis in 1985,1986 and 1987
o
Age class
1
2
3
6+
Year: 1985
Size dass
Size dass
<=80
100
150
200
>=250
<=80
100
150
200
>=250
Area: North Quarter: 1
100.0
84.13 15.87
83.72
16.28
83.33
16.27
100.00
Area: South Quarter: 1
100.0
4.82 95.18
86.47
12.78
0.75
100.00
100.00
Area: North Quarter: 3
[No information: ALK 1986/3 North used]
Size dass
<=80
100
150
200
>=250
Area: South Quarter: 3
100.0
32.89 28.38
37.67
1.06
10.40 49.27
34.30
44.45
3.12
33.33
1.87
1.04
22.22
100.00
41
Table 4.2 ctd
o
Age class
1
2
4
3
5
6+
Year: 1986
Size class
<=80
100
150
>=200
Quarter: 1
Area: North
100.00
92.14
7.86
52.94 47.06
100.0
Area: South
Quarter: 1
[No information: ALK 1985/1 South used]
--------------------------------------------------------------------Size dass
e
<=80
100
150
*)
200
>=250 *)
Size dass
<=70
80
100
150
200
>=250
Area: Nortb
100.0
92.06
7.94
87.10
36.36
Quarter: 3
12.90
36.36
9.09
18.18
100.0
Area: South Quarter: 3
100.0
99.20
0.80
26.70
2.59
70.71
6.26
2.36
91.29
18.18
36.36
36.36
0.09
9.09
100.0
*) copied from 1986/3 area south!
Year: 1987
Size dass
<=70
80
100
150
200
>=250
Area: North Quarter: 1
100.0
67.11 32.89
15.71 84.29
82.37
12.78
33.33
33.33
0.75
33.33
100.0
Area: South Quarter: 1
[No information: ALK 1985/1 South used]
Area: North Quarter: 1
[No information: ALK 1986/3 North used]
Size class
<=70
80
100
150
200
>=250
Area: Soutb Quarter: 1
100.0
99.20
0.80
26.70
70.71
2.59
6;26
91.29
2.36
36.36 36.36
18.18
0.09
9.09
100.0
i
Tab1e 5.1 Average stomaeh eontent weight (g) by predator size class, quarter and year.*)
Predator: Cod
Size elass:
__
50
70
100
150
200
250
300
400
350
500
600
700
800
900
1000
126
153
. ..------._ ...-------------------------------------- ..----- ......... _------_ ..- ..----------.---------_..--------- ..-----_...... __ ...... _-------------------------_ .. _-_ .._---_ ........__.. _----- ..... _-------_...... ---......--... _---------....- ..
.
0.58
1.82
6.90
1972
13.3
18.8
43.3
0.63
1.99
7.99
17.9
33.7
66.8
1966
Quarter 1
0.18
" 2
" 3
0.17
0.42
1.76
4.89
11.3
25.3
44.3
" 4
0.18
0.46
2.12
4.04
15.9
32.3
66.7
70.6
98.6
107.
64.3
167
77.6
105
140
----_.. _-------------------------------_ ... _-----_ ........ _-------------_ ......._-------------------_ .... _----_ ... _--------........... _----------_ .......-_.. _----_ .........._---_ ... -_ ...__... __ ... _--_..-_ ....-...... _-_...... _---_.. _............... _-_.......-... _-_ .. __... _-_..... _1981
Quarter 1
(0.00)
" 2
0.38
0.64
1.06
2.04
5.21
14.45
37.14
83.84
164.71
0.29
0.76
1.29
3.13
8.15
14.86
37.03
111.68
(189.01)
" 3
(0.09)
0.33
0.90
1.44
2.35
6.55
17.01
38.84
137.84
376.46
" 4
(0.23)
0.25
0.63
1.34
2.63
5.80
13.37
30.23
104.14
148.34
0.40
0.67
2.27
2.42
5.81
12.67
22.35
39.17
70.46
117.26
112.99
250.24
0.19
0.33
(0.26)
1.16
2.06
4.66
9.67
18.24
30.87
76.60
67.51
138.02
(324.18)
Quarter 1
(0.06)
0.36
0.86
1.98
3.90
7.31
1986
8.80
19.57
35.44
44.13
86.54
107.42
159.31
" 3
(0.13)
(0.23)
0.55
1.34
2.97
5.10
8.42
14.94
33.03
50.67
71.69
127.39
(443.14)
Quarter 1
0.27
0.57
1.24
3.14
5.27
9.02
15.02
17.53
48.31
83.36
81.46
151.49
" 3
(0.17)
0.27
1.58
2.91
5.79
8.08
17.08
31.45
54.27
91.94
171.03
(291.99)
1985
Quarter 1
" 3
1987
*) When based on 1ess than 25 stomaehs figures are in braekets
--_. -
-
-
- --
--~---------
Table 6.1 Percentage of empty stomaehs by predator size class. quarter and year.*)
Predator: Cod
Size class:
50
70
100
150
200
250
300
350
400
.
500
600
700
800
900
Quarter 1
7.7
8.7
7.1
1972
9.5
14.2
14.0
10.9
7.7
12.9
" 2
12.3
11.9
13.8
15.0
12.1
11.4
(20.0)
2.9
(25.0)
" 3
16.4
15.7
10.8
13.1
12.5
13.2
7.7
18.2
(15.8)
7.3
8.8
7.0
2.4
5.0
10.0
7.3
1.9
4.9
1966
" 4
8.0
1000
1981
Quarter 1
(100.00)
" 2
12.39
11.16
11.30
12.15
9.68
10.11
17.63
15.35
16.24
11.11
15.34
15.55
11.08
9.29
9.46
5.61
1.11
(0.00)
" 3
22.22
12.96
9.48
24.14
15.68
13.78
16.62
17.44
13.23
38.78
" 4
(0.00)
20.63
12.56
13.57
12.45
9.91
8.91
6.84
3.08
7.41
4.88
4.40
12.60
11.58
10.95
1985
6.80
8.47
5.14
16.56
9.52
8.18
6.67
2.94
7.14
(0.00)
14.29
13.36
11.15
6.91
8.88
11.90
12.37
15.83
11.39
(6.67)
Quarter 1
(0.00)
9.75
10.33
8.68
6.19
8.60
1986
10.94
12.06
6.06
8.20
14.62
17.12
15.63
"
(53.85)
4.76
19.12
16.61
12.62
13.98
8.71
9.02
7.33
9.65
2.38
4.29
(0.00)
Quarter' 1
15.73
10.65
9.60
7.90
12.02
1987
9.49
6.25
5.88
7.27
10.00
11.49
19.05
"
(33.33)
17.98
19.92
13.44
11.95
15.42
14.76
15.65
12.64
19.67
9.26
(7.69)
Quarter 1
"
3
3
3
*) Whenbased on less than 25 stoIJ?-achs figures are in brackets
45
Table 6.2 Percentage of empty stomaehs by predator size cIass, quarter and year.*)
Predator: Whltlng
Size cIass:
e
100
150
200
350
300
250
400
500
Quarter 1
18.49
21.56
21.54
28.11
1981
28.24
21.84
2
16.12
23.54
24.41
21.19
19.31
26.42
3
22.51
25.86
21.40
26.61
26.36
26.38
(33.33)
4
22.52
18.50
24.14
20.95
21.22
6.36
(0.00)
Quarter 1
15.31
13.13
16.08
11.12
1985
21.35
14.92
16.48
(100.00)
3
5.53
8.05
6.81
6.14
4.40
1.73
7.46
(0.00)
Quarter 1
4.25
2.40
5.53
6.52
1986
5.21
2.60
(0.00)
3
0.30
1.24
2.04
0.00
0.17
0.00
0.00
(0.00)
Table 63 Percentage of empty stomaehs by predator size cIass, quarter and year.*)
Predator: Salthe
Size cIass:
250
300
3
(0.00)
(0.00)
Quarter 1
500
1980
16.28
100
1000
24.00
(31.25)
(60.00)
8.57
(0.00)
(33.33)
1981
22.02
15.87
(25.00)
(0.00)
Quarter 1
.
400
(0.00
.
2
(14.29)
(14.29)
0.00
4.42
(0.00)
..
3
28.89
12.28
41.32
18.52
(0.00)
..
4
0.00
13.41
25.64
26.01
6.61
15.63
1982
25.11
64.00
(100.00)
3
26.42
5.95
9.00
8.82
(0.00)
4
(0.00)
(18.15)
5.56
2.90
(0.00)
33.33
(11.76)
1983
30.43
34.15
(100.00)
1984
(20.00)
(0.00)
Quarter 1
Quarter 1
(0.00)
(0.00)
Quarter 1
3
Quarter 3
(0.00)
0.00
3.17
6.92
0.00
10.73
12.25
1986
12.80
10.31
*) When. based on less than 25 stomaehs figures are in brackets.
(0.00)
46
TabIe 7
Specification of record format for exchange of stomach content data
Position
-
1-2
3
4- 6
7- 9
10-12
13-14
15-16
17-18
19-22
23-25
26-29
30-39
40-44
45-51
52-54
55-57
58-60
61-70
71-77
78-85
86-91
92-100
Name
Type M/O Range
*)
**)
Record type
Quarter
Country
Ship
2A
IN
3A
3A
3A
2N
2N
2N
4N
3N
4AN
ION
5N
7N
3N
3N
3N
ION
7N
8N
6N
9N
Gear
Year
Month
Day
TimehauIed
Fishing depth
Square
Predator code
.. Predator size code
Number per hour fishing
Number with food
Number regurgitated
Number empty
Prey species code
Prey size code
Prey weight
Number ofprey
Paddingfield
M
M 1 to 4
M
M
M
M 65 to 99
M 1 to 12,99
0 1 to 31, 99
M o to 2400, 9999
0 o to 500, 999
M
M
M -1 to 99999
0
M
M
M
M
M
M
0
-1 to 99999
Comments
Fixed vaIue 55
lCES alpha code ***); defauIt XXX
ICES alpha code ***); default XXX
lCES alpha code ***); defauIt XXX
Notknown 99
Notknown 99
Notknown 99
In GMT, not known 9999
In metre, not known 999
ICES Statistical rectangIe
NODC 10 digit code
See ANONYMUS, 1984, Appendix I
Not known: zero mIed
NODC 10 digit code
See ANONYMUS, 1984, Appendix I
In mg
No information: space filIed
Space fiIIed
*) All numeric fields (N) rightjustified, zero fiIIed, unless otherwise indicated; All alpha (A) and mixed
alpha/numeric fieIds (AN) Ieftjustified, space fiIIed.
**) M: mandatory; 0 : optional.
***) see ICES IYFS exchange tape specifications.