ICES STATUTORY MEETING 1993 C•H. 1993/M: 15 Anadromous and Catadromous Fish Committee Ref.J.

SIZE OF THE SEA TROUT /SALHO TRUTTA L./ EGGS BASEn OB SEVEH IBVESTIGATEn POLISH RIVERS.

by

R. Bartel i /, H. ParlinskaZ/

1/ Inland Fisheries Institute • River Fisheries Laboratory Reduta Zbik 5, 80-761 Gdansk,

c/ Waraaw AgriculturaJ University Rakowiecka c6/30 02-528 Warszawa, Poland

ABSTRACT

The aim of the paper was to compare size of sea trout eggs from 7 Polish rivers. Length oF females varied from 39 to 91 cm .. The biggest females were in the River and the smallest ones in the River, average lengths were 69.9 cm and 60.2 cm, respectively. Egg atze was correlated with length of females. It

was ataled some difFerences of egg atze among sea trout populations. It was not statcd that egg atze from one river was bigger in compare to other populations. LICES STATUTORY fvlEETING 1993 C.M.1993/M:15 Anacat Fish Comm. " Ref.:J. Size .Qf the sea tro~t (Salmo trutta L.) eggs based on seven investigated Polish rivers.

Ryszard Bartel 1/. Haria parli6skae/

1/ Inland Fisheries Institute in Olsztyn. River Fisheries Laboratory 1n Gdansk.

2/ Main School of Farming. Warsaw . •

1. Introduction.

The aize of egge is a charactp.ristic feature of each

speeies. however there ean oecur relatively big differences in

their aize. the latter being related to a number of affeeting

faetors, with the main ones being as follows: the fish age l.?O."~~<2.M~'Q:I NlJkg-n clro ... ~'11-9 (Sklower, 1930; Davis, 19~3; Skroehowaka, 19~3; artel, TU) the

size of spawners (Juszezyk, 19~1; Pekarkova, 19~6; Allen, 19~8;

Dumas, 1961; SehMperelans. 1961; Sakowiez, 1961; Seott. 1962; • Steffens, 1963; Me Faddp.n et al., 196~; Szezerbowaki, 1966; ~h t.l kCVii :Ü·;'(' et a..t. ~ Bulkley, 1967; Hardy, 1967; Farid Pak, 19~ both - the fish age

and the size of spawners (Terleeki, Kempinska, 19~6; Sakowskaja,

1973; Chelkowski et al., 198:5) and the jemales feeundity (MMär,

1949; Svärdson. 1949; Rounaefell, 19~7; Allen. 19~8; Pope et al.,

1961; Seott. 1962). Some authors indieate the changing environmental eonditions

aa a factor affeeting the atze of eggs. Me Fadden et al. (196~)

coneluded that in the caae of brown trout there were observed

<1ifferences between populations from some rivers an<1 these 2 - .'

differences lied in different diameters of eggs what in

consequence found its refleetion in feeundity. AI~o Larsson and

Piekova (1978) and Anohina, Bakulina (1990) observed differenees

in eggs size of salmon from various rivers. Määr (1950) relates

the differenees in eggs size of po'pulations of Salmo alpinus to

the fish size and ·.their feeundi ty.

The sea trout oeeurs in all the Polish rivers flowing into

the Baltie Sea. There are some growth differenees between these

populations, and theRe differenees are mainly visible between the

trout population from the Vistula river and the populations of trout from the Middle and Western (Chrzan, 1959i • Zarneeki, 1963i Chelkowski, 1969i BarteI, 1988).

As there are some differences in growth of sea trout from

Follsh rivers the question waa raiaed whether there are also

differenees in aize of eggs of these various populations.

2. Material and methoda.

During the artiflcial spawning of the Vistula sea trout

performed in November and December of 1983 at gwibno and the

artificial spawning of the Pomerania trout - from thel:.eb<;1.'...riv.:: •

in I:.eba, from the S}upia river in S}upsk, from the river

in Darlowo, from.the Grabowa river i~ Je±yczki, the Parseta river

in RotJcino, the river in Trzebiatow (Fig.l.) - some dozens

of eggs have been colleeted from part of the femal es.· The egga

were submerged in water in order:to let them swell and on the

.. . . following day the volume· of dislodged water, by 30 eggs, was ; measured. The obtained values were used in further eonsideration.

The eggs were collected from 1825 females (Tab.l) measured with 1

cm aecuraey. This numher of females made up 54.7X of all the

artificially spawned. females of sea trout. in 1983 (BarteI,

I .------I

~",..::"

- 3

Zielinski. 1986} • Thi S ,perc,e.nta.ge ranged from 45.01. for femal es

from Grabowa and Rega rivers to 73.51. - from the Slupia river. The

eggs for the measurements were collected from two spawnings in

both heba and Pars~ta. up to seven spawnings in Slupia (Tab.1).

The one way analysis of variance and the linear regression

were used to study the eggs size from the 7 Polish rivers. The

linear regression was applied in order to achieve an answer to the

question whether there are diffe~ences in stze of eggs obtained

from t~out populations from different rivers. For the cases when

sampIes from·the 7 rivera were available the following equation of • linear regression was determined:

y = -+- b:x:

where:

x - volume of aea trout egga from the river "I". i = 7

Y- volume of sea trout eggs from the river "y". j = 7

At the significance level L = 0.01 the hypotheses were veryfied:

Ho : b = t. and Ho : a = 0 •what ls equivalent to the sUbstantial hypothesis assuming that the volumes of sea t~out eggs are the same. The analysis was performed

on a basis of mean values and for the range of fiah length 57-83

cm. For all the listed rive~s the re~ression fun~tion. describing

the dependence of eggs volume (feature "y") on fish length (feature "x"). was etetermine<1. Sucl1. anal ys1s was made for both the

original data and the mean values.

The PeorsonJs test XC was applieet to check the agreement

betwcen the etlstrlbution of Investigated features (eggs volume and

fiah size) and the 'normal distribution. - 4 - Calculations made for the Pars~ta river gave the following results:

TESTIHG OF HYPOTHESIS

HO: Volume of eggs has normal distribution

x test function = 1.~3~

x critical value (1,0.0~) = 3.841

HO ACCEPTED

TESTIBG OF HYPOTHESIS HO: Volume of eggs has normal.distribution •

x test function = 1.~3~

x critical value (1,0.01) = 6.63~

HO ACCEPTED

TESTIHG OF HYPOTHESIS

HO: Fiah length has normal distribution

x test function = ~.647

x crltlcal value (C,O.O~) = ~.991

HO ACCEPTED

TESTIHG OF HYPOTHESIS

HO: Fish length has normal distribution

x test function = ~.647

x critical value (2,O.Ot) = 9.2t

HO ACCEPTED

The test~ conflrmed the agreement between the obtained distributions and the normal distribution. 5 -

3. Results

3.1. I~ength of females which underwent the artificial spawning.

The ll'!'ngth of females which undprwent the artificial spawning

fluctuated from 39 cm in Grabowa river to 91 cm in Rega river. The

biggest mean length was observed in the case of Vistula sea trout

and that reac.hed:.69.91. c~, whi le the lowest mean l~ngth of 60.22

cm was found in Grabowa river. The mean'length of sea trout fr.om

the Pomerania rivers ranged from 60.22 to 65.04 cm and was

considerably . lower than in the case of Vistula sea trout (Tab.1) ..

These considerable differences resulted from applying of criterion

during gathering of 'spawners caught in Vistula's mouth, at .gwibno . • .Only the spawners weighing above 2.5 kg were sele'cted while such a

criterion was not applied in the case of remainin~ rivers. The

calculated mean )engths of sea trouts, from their length range

57-fit, gave similar result. The mean length of sea trouts from the

Vistula was of 68.8 cm while the fish from remaining rivers had

length varying from 62.7 cm to 66.9 cm (Tab.2). These distinct

differences in mean length between the sea trouts from Vistula and

from the remaining rivers resulted from more common occurrence of

trout females in higher year-classes. For example - the number of

Vistula sea trouts, in the length class 72-76, made up 26.51. of

the total weight of Vistulatrout ußed for spawning. In the case

of remaining rivers the share of this length class ranged from

6.51. in Grabowa river to 16.91. in Pars~ta river. Guite an opposite

plcture gave the 57-61 cm length class as it made up only 9.41. in

the case of Vistula sea trout and from 15.81. in the Rega river to

381. in the Wieprza river, the latter two representing Pomerania

rivers (Tab.2).

The trouts from Slupia and Wieprza were observed in 7 and 4

spawnlngs, respectivel y.. In both cases t.here was a vi sibl e - 6

decrease in length of famales spawned in subsequent spawnings

(Tab.3 and 4). Similar phenomenon, though not so strongly pronounced, was observed in the case of trouts from Slupia river,

being in similar, ~7-83 cm, langth ranga (Tab.3).

3.Z. Egga aize. The eggs size determined by volume of dislodged water by 30

3 3 swallen eggs ranged from 1.3 mm to 3.82 mm •

The first volume concerns ~he trout from Slupia river,

the length of ~8 cm, and .the second ~ the trout from Leba river with the lAngth 77 cm. • The biggest mean volume of eggs, calculated for the whole

sampIe for the given river, showed the trout obtained from vistula

~ w . 3 river and that was of 2.~6 mm , while the lowest one, 2.20 mm ,

was found in trout from Grabowa river (Tab.!).

3.3. Effect of female atze on the egga aize.

The results from the 7 investi~ated river~ showed that the

s1ze of eggs was incraasin~ with the increasing length of spawned

females (Fi~/2) • Calculation of dependence between the eggs size ;:lnd the female size was limited ~o the length range ~7-83 cm and • it. gave positive correlation with the correlation coefficients

which are as follows (Fi~.3):

1"1 = 0.906 Wieprza river 1"2 = 0.937 Slupia river

1"3 = 0.6~0 Grabowa river river 1"4 = 0.814 Leba

O.8~8 rlver 1"5 = Hega 1"6 = 0.782 Pars~ta river rlver 1"7 = 0.746 Vlstula

-

I .... - 7 -

r 8 = 0.866 all the material.

This dependence, for p~rticular rivers and for the whole material

in the length range 57-83 cm, can be circumscribed with the

followingequations:

Yl = 0.214 + 0.035 x Wieprza

v~ 0.398 0.031 Shlp1a ·C = + x

Y3 = 0.630 + 0.026 x Grabowa

Y4 = 0.058 + 0.037 x Leba

Y5 = 0.450 + 0.029 x Rega

Y6 = 0.552 + 0.027 x ParB~ta • Y7 : 0.856 + 0.024 x Vistula Y8 : 0.453 + 0.030 x whole matert"al.

As it arises from the above functions t.he dependence of eggs

volume on fish size is, in each case, signif1cant at the

confidence level L = 0.1 and it 1s similar in the case of all the

rivers.

3.4. Differences in size of eggs obtained from various trout

populations . • The calculated mean volumes of t.rout. eggs from the 7 rivers, and for fish length being in the range 57-83 cm, showed a visible

differentiation (Tab. 1 and 3). At the same time the mean lengths

of spawned females from the 7 rivers considerably differed (Tab. 1 ,

2). As there is dependence between the length of trout females and

the eggs volume (Chapter 3.3) the·analyais, leading to finding of

pOBaible differences in eggs atze from various populations, was

baBed on mean eggs volumes for the fish of length range 57-83 cm.

It was found that the trout egge from one river are not by

far bigger aB compared with e~gB from the.remaining rivers. A - 8 -

considerable differentiation w~s, however, observed between volume

of eggs obtained from' populations from somerivers (Tab.5).

One way analysis of variance (characteristic - eggs volume,

factor river) confirms the differenti~tion in eggs volume

depending on the river, therefore, on the environment (Tab.6).

4. Diacuaaion

In populations of the sea trout from the Polish rivers there

are obaerved spawners which hav~ gone through one aeasonal stay in

the aea (A.O+). two or three stays (A.1+; A.E+) or older. The femalea at the age of A.1+ and A.E+ represent the higgest share in • apawning. The share of ind1vidllala at the age A;O+ 1s lower and at

the age A.3+ or older is yet lower (Chelkowski, 1969; Zarnecki,

1963) .

Lt is known from the scale reading that the trouts from

Pomerania rivera reached the length from 41 cm to ~8.6 cm - after

their first year of atay in the sea; from 60 cm to 68.9 cm - after

the aecond year and from 67.8 cm to 77.~ cm - after thp thirrt year

of residence in the se~ (Chrz~n, 19~9; Chelkowski, 1969, 1974).

The Vistula se~ trout reached at A.O+ - from 4ö.E cm to ö5.c cm, at A.1+ - from 62.9 cm 'to 67.7 cm, at A.2+ - from 76.6 cm to • 79.9 cm (Zarnecki, 1963; Sych, 1970).

The tagging experiment showed that the trouts from the

Vistula reached 47.4 cm - ö3.7 cm - after the first aeason, 68.3 -

69.ö cm - after the second season and 7~.3 - 79.4 cm - after the ßa.d'.ie. L·ß,).,ül ~g' thi~d seasonin the sea Pa}ka, Bieniarz, 1983; Bartel, 1988).

The tagRed tronts f'rom Grabowa river reached on average ~1.e.

cm (range 40-6~ cm), 62.3 cm (rang~ 40-77 cm) and 68 cm. after the

first. the aecond and third year of stay in the sea waters, - 9 -

respective I y .(ßl.-l".YtI?L .dS1),'

Taking the above data into account it canbe said that in the

collected material from the Vistula river there prevailed

individulas at the age A.1+ and A.2+. The share of older age

groups was insignificant. The materials gathered from the

Pomerania rivers included also the age group A.O+, but its share

was small.

As the age of femals, from which the eggs for size

determination were gathered, was not defined and, as, at the same

time, the length distribution of the trout made it impossihle to • segregate iish into age claases it is difficult, in such a s 1. tuation, ", t'o state about, inf I llenC':e 0 f' fema IR 'age onto eggs size'. '

However, the observed by numerOUB authors effect of female'g

length onto eggB size (Juszczyk, 1951; Pekarknva, 1956; Allen,

1958; Dumas, 1961; Skliperelans, 1061; Sakowiez, 1961; Seott, 1962;

SteffenB, 1963; Me Fadden et al., 1965; Szezerbowski, 1966;

Bulkley, 1967; Hardy, 1967; Farid Pek, 1968; Chelkow~ki et al.,

1985) was also visible in the ease of the trout from Vistula and

Pomerania.

Ther.e were observed some differeneeR in si7.p. of eggR

originating from variouB trout popUlations, and a similar

phenomenon was observed in salmon from three Swedish rivers

(Larsson, Piekova, 197A) and in salmon from Russian rivers

(Anohina, Bakulina, 1990). Some authors were relating theRe

differenees to fueundity of brown trout (Me Fadden et al., 1965)

or to the size of Salmo alpjnus L. females,and their flleundity

(Määr, 1950). However, in the caBe nf trouts from Pollsh riverB

there was not obaerved domination of egga aize of any popUlation!

though some dlfferenees between popUlations were seen. - 10 -

Acknowledgements:

The authors would like to thank Dr~. Goryezko, M.Se. K.·

Becker and Mrs. J. Rozek, the employees of the Inland Fisheries

Institute, for their help during eolleetion of the material, and

Mrss. H. Masierak and J. Kardela for their assistance when

elaborating the data.

/Translated by Mrs. M.Pastuszak/ •

-e

~ ; .n Table 1. Number of sea trouts spawned in 1983 in 7 Polish rivers and number of sea trouts from whieh the eggs for size determination were eolleeted.

F e m a I e s Bumber of Length of Average spawnings females (em) volume of 30 egge Ho. River Loeality Spawned Observed Total Observed Average Hin. Hal[. sn (mi) Ho. Ho. Y.

1 . Vistula Swibno 163 118 72.4 4 69.2 57 83 7.625 2.56 2. Leba Leba 273 142 52.0 2 63.0 47 80 9.723 2.39 3. Slupia Slupia 795 584 73.5 7 63.6 44 82 11 .930 2.33 4. Wieprza Darlowo 411 241 58.9 3 64.5 48 82 9.548 2.44 5. Grabowa Jezyezki 903 406 . 45.0 3 59.3 39 82 10.928 2.20 6. Pars~ta Roseino 188 90 47.9 2 63.8 48 79 8.461 2 .28 ...... 7. Rega Trzebiat6w 545 245 45.0 3 64.7 49 91 11.153 2 • 3~ ......

TOTAL 3340 1826 ~4. 7 24 39 91

. , Table 2. Average l~ngth of females (ern) and share (;.) of sea trouts frorn 57-81 cm length range in five-centimetre-length-elasses and rnean volume (mm) of30 eggs in 7 Polish rivers.

Bumber of Pereentage of" females in length classes Average length· SD Average volume of" Rlver females 57-61 62-66 67-71 72.-76 77-81 (cm) 30 egfs (mm ~' ..

Vistula 1 17 9.4 14.5 38.5 26.5 1 1 . 1 69.8 2.60 Leba 106 20.8 27.4 37.7 7.5 6.6 62.7 2.39 Slupia 456 29.2 29.2 26.3 12.3 3.0 65.4 2.40 Wieprza 184 38.0 25.5 16.9 16.3 3.3 65.0 2.50 Grabowa 276 30.8 3915 23.2 6.5 64.0 2.29 Pars~ta 77 29.9 22.0 29.9 16.9 1 .3 65.7 2.31 Rega 209 15.8 29.6 36.4 13.9 4.3 66.9 2.39

IV I Table 3. Average length of sea trouts from Slupia in length ranges 44-85 em and 57-83 em spawned in 7 sUbsequent sapwnings and average volumes of 30 eggs (mI).

Subse- Date L E B G T H 0 F T R 0 U T F E HA L E S (em) quent s:paw- f'rom 44 em to 85 em from 57 em to 83 em n1ngs ' . Bumber of Length (em) Volume of' Bumber of' Length (em) Volume of' SD 30 ergs SD 30 efgs females average range (mI f'emales . average range (mI . from to f'rom to

1 .02. 1 1 64 65.3 48 - 8e 6.47 e.319 60 66. 1 57 - 82 5.64 2.332 2 11. 11 74 64.7 50 - 85 7.02. 2..356 66 65.7 57 - 80 2..386 3 15 . 1 1 36 65.0 53 - 83 6.65 2..301 32 66.3 57 - 83 2..357 4 17 . 1 1 65 64.8 50 - 80 6.65 2..374 57 66.3 57 - 80 2.403 5 2.1.11 55 61 .9 44 - 78 7.30 2..32.9 42. 64.8 57 - 78 2.387 6 2.4.11 116 62..6 48 - 83 7.36 2..352. 90 65.4 57 - 83 2.42.4 7 2.9.11 174 60.2. 45 - 83 7.56 e.2.92. 1 1 4 64.3 57 - 83 5.83 2..443

TOTAL: 584 62..8 44 - 85 7.40 2.32.6 461 65.4 57 - 83 2.339

...... - 14 -

. Tabl e 4. Average 1ength (ern) ofsea t.rout femal es and average vol umes ,I of 30 ~ggs of Vistula sea trorit in 4 subsequent spawnings.

~.

Tahl~~. Gomparison of average volumes of sea trout egga from 7 Polish rivers.

Vistula Pars~t.a Rega Wieprza l:.eb~ Grabowa Slupia

x x Vistula 0.07 0 -0. 14 -0.16 O. I 1 -O.O~ x Pars~ta -0.07 -Ü.21 -0.23x -0.04 -0.12 e x x Rega -0. 14 -0. 15 O. 11 -O.O~ Wieprza -0.02 0.25x 0.09 Leba 0.27x O. 1 1 Grabowa -0. 15x Slupia

NIR = 0;13 x - differences at the sign1ficance level p = 0.01

1;. ~1' , _. ...~ .. - 15 -

Table 5. One way analysis of variance.

Feature: volume ():f egga Factor: river

- Vistula

Co - Pars~ta 3 - Rega

4 - Wieprza

5 - 1:.eba

5 - Grabowa

7 - S}upia • Table of analysis of variance

FACTOR OF DF MS F ernp

blocks 24 0.25 10.49xX factor 5 0.25 10.55xX p.rror 144 0.02

Mean vector

2.45 2.39 2.45 2.6 2.52 2.35 • 2.51

NIR = 0.13

xx - L=O.Ol - 16 - r~e fe I-enees

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diameter of its eggs.Zool.pol.16,34:195-201. - 20 -

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• Fig.l. Places of ürtificinl ~r,"1'.'·f1jrl(l f-f '30:l trPlJt in f.'(.ll:llld .

..

• " -. m~ A VIS1\JLA 2 - -- 5tlJPIA 3,0 3 ...... W\E.l'R~A 3,0 'i LEf,A 5 -- -- ~RAßOh'fI ••• 6 • 4 ...... , .... . RE~A • . • '1 ------PAR'i;.TA .• •. ..,• •' ,. •• • 2,5 2.'5

..... • :3. • •• ...

2.0

1-----:+----l----+----+----~--_l_---l1l.,:l- Lt1- 52- 57- 62- 67 - 12. - 11-B~ -5-1 -56 -f,1 -106 -:t1 -16 c.m

Fig.2. Average volume Imll of '3D eggs aoainst length in 5 centimetors einsses 'of sea traut fram 7 Polish rivers ·. •..

2.~

2.8

2.6

• 2.257 67.4 72.6 77.8 83: cm

1 - Y=0.214+0.035tX (Wieprza) 2 - Y=0.398+0~031tX (Slupia) ~ - Y=0.63+0.026tX (Grabowa) 4 - Y=0.058+0.037tX (Leba) 5 - Y=O.45+0.029tX (Re9a) 6 - Y=0.552+0.027tX (Parseta) 7 - Y=0.856+0.024tX (Vistula/ 8 - Y=0.433+0.03tX (all materialsl

F;_~. 3 - Relationship of a volums Imll of 30 eggs a..::ainst • s~a tr0~tl~nffthin 7.Eolish sea ttout ~opulations.