HomeMy WebLinkAboutSUS3505 ,/ 5
TERSKELPROSJEKTET WJ
SUMMARIES FROM THE WEIR ?ROJECT INFORMATION BULLETINS
TERSIUZIIES IJlCYIUIIIIIG 'A BIOLOCISKE P'ORIIOlD I
RECUL&RTE WoSSDMG -(TERS ICEL P IllOSJRTET)
THE WI R p ROJECr
PUBLIJUSJONSOVERSIKT OG SAM LING AV SAfiMENDRAC F RA
·."E ~I ELP IlOSJE I T!'T S I NP'ORMSJONSS ERIE
StJtIMAR l ES rJlON THE WE I R PROJECT INI"OMATtON BUUZT'IMS
pA L ME LLQUIS T
MY!-VASSDRACSO IRE KTORAT!'T
NORWEGIAN "ATER RESOU RCES AND E LECTR ICITY BOARD
1984
)
.:..IKNISU ••••......STILLI.........==MaDS'!'I 8DilI:
OMi DOTS ...,.
,
CDEML I.....'1'1011
The we ir pro ject,-qeneral lnfo~tion.(Inf .no 1)................•
Publications with data fra.The ..ie Proj~.......... . ..........)S
PHYSICAL AND ClfDU CAL COIIDITIOIIS
Phys ical a nd c halice.par_un at the i n l. t.and outlet of t.he
..i r ~.ln a t EIlM,!••t rlll «Jal. " .I l nf .no 16 )••••••••• • • •••••••••••2S
I nput and output o f oeq. n ic ..te ri als t o the ..i r ~.tn at I ....
Ell s inged.a ••".I[nf .no 1 0 »•••••••• ••••• • ••• •• • • •••••••••••••••••••••I'
V!G£TATJQfiI
A s urvey of veqetat ion in t.he upper e .t e~nt ar••of the flYer
Eks inqedal ••l.,.n...s t arn Norway.(I n f.no Ill .. ..... .. .......••••••20
IlE1mtOS
Inv ••t i qat i ons of t.~botte.f .u~of requlated ft..ra.with ~l.l
Mlphni s on blacll-f Ues ,(Di pt..ra .S 11N1iid ..)..U n t.no I.15
The .ffee t of ..i rs on -.crco.n thoe i n requlat ed f l ..r s ,with apee i.1
.-phas i.on blac.-flie.CDi p t er ••S t ~l i id••).(t nf .no 2)'.........))
T rout.bu r~and batte-i nn r t e b r .t e .i n t he ri ve r ....eentr.1
Norw.y.before bOi ld it'llJ o f ..i r ••et nf .no 9 )....••••••••••••• ••••.• I I
Benthie an ~1 s t udtes in the E.s it'llJeda len r i v er at E after
r eq u lat i on and we ir-bu i ldit'llJ.(t n f.no 1)'•••••••• •2 2
Ben t hie antaa l ?r oduetton i n t hot E ••i t'llJed.len river at E...after
r .-qu l!lt i on and we i r-bu i ld i nq.I t n! .no 1 5 )••• • • •• •• •••••••••••••••••2.
Dr ift o f be nt hi e ani..l s in t ~and out of t he we ir bas in at Et...
(tnf .no 1 4 1 ..••••••••••••••••••••• ••••••••••• •••• • ••••• ••••••••••••2 )
'ISH
The trout population in the r ivet'"'tk~la ~fore the construetion
o f ...irs .Ctnf .no 4 )•• • • • ••••••••• • • • • ••••••• • • ••••••••• • • • ••••••••II
The populat ion o f brown trout esa l ao tt'ut t a L)the r t ..r Mer.edela
af t er eonstr uet ions o f i t'••Cl rt t .no 17 )26
•
1'r e ,tM.Irbot .~blX ta.I n .-n.bl'at ••in tM r ,-.~I'al
r .,ay.bolI t or.bui.l.'i ~of _ir s ,(I nf .rw '....1 1
IIt l l f t t lon.pupu l Jlt ,on l •• •<)t'O"IIth "Ad IWtl:,.At g f bl'~trout:
I.1.-.0 tr u t t ..L ••1n ttl.rlYer E". i.A>fN al..l vre n.-.-ern "_'I
N fo re r III tL on o f t et eee , U nl ..no i )................. ..... .. .. .. .. .. .. ..U
pt 11 \)ft.o.ns ' t y ."",r t .J hty .snJ qr owt.!lI of !:tr~t.r~j I
t ~U )f .In (SoIL",tntt ..L.l st s ..".SIu.LRlI..a.len.u nt .~•.lO).29
n i.t ..,..,.J -..(t .h t Y'f b e n tr~t (H I .,t.e ~~UI :".,olcIM t.:.en
2 y ~..r.4t!'l.-.sl.rIIJ oi l .,!'!ri ve r .(I n t .no 21)••••••••••••• • •••••1 0
"""'.fI t l Oft of ( n tCOlJ t,t S.l -o UIJ tt Jl L .)I n ;,lptNl:~,t of t M
'l v. r !'.i1...N 41 .~lv ".(I n f ."10 12 )•••••• •• •• • •••• ••• • ••••• •••••• • • •2 1.
•"'C th,a t '''i.~.1 M ,.eld t tU:\JW n t(~t.1ft rl ve e "l lt~u·
.1".It 1...t {"' .IIy .(In t .11 0 ••0 1 -1
tea.b e n (cQUt t l.De r y of rl v. r .....il .....t :!toc ....1il" .
In t .-so,1.,.................... . ............................... . ..2
~be r ~tr ou t of t he ri ve ra ~t l l~J.1 ••1v .4 nJ ~.1 •• ••t.rn
~r ~lJ 'I .A~e .'1 r owt !'l .f ood .and lI iqrat ion.(I nt .no 22 .••• •• • ••.••••••II
l ...o::lf1on8 t ylNnq a oita.>n .tond trou t in t h Ol!!ri v l!r ";"')o3lW ~fo re
ouI IJ lnq o f ..e i.r a.t i nt .no SI ........... .. . .........••••••••• •• ••••1:
Pt I t Jl t l.nt lc !l oll f S .t.o ••t u L .)I rkl ,own t [\)Ut !S.t.J
trut t .L.)Jlf t e r ydr o-e t ect r i c ~Y.lopae nt .l nd lt d l ~o t ..l CS
u t t he ri ~r 3 ,j~.no r t h Mo C..A!'.(l nf ."'0 1 4)••••• ••• •.••••••••.••::,
.l~~.r t.o t t~~r l ve r ".1 11 r~~.1 .•1w.~u rt.~t !'l.r-ll ~
y to 1 •.suq us t 1 .7 ~.t i nt .no 2 1 •..•...• .•.• . •••...•.. •• . ••
~~.~rt ~blrd li t e i n ~n u ~r f ~i r slns ..1 ':.D e rL v ~r
,a l:"IQed..h e lv <t i n t lw .u .-er f 1i 7\.(I n t .no ),.. .... .... . . . . .. ..10
P l ::o KI 1 1 ~U I.\T m R I VEki
e.~r ':.!'l .t oc ~i ~.lnd y ie ld 0 1 ~[n tr t 1n C1 V¥C a 1 I nqd.l s -
et v .t l " t .no 7 ).......... ..... ..... ................................1 "
~Or n ,::rou t f i .~ry of r i v.r M...!l .e ast ~QC w~~1 ~7 ~.~I n (.
nut s,•• • . .••.•••.•.•..•.•••. •.•••••• •••.••••....••. ••.••...•...•••.2 7
T1Mt "ir Prl',)jeet.a ~rat i"r.Hareb project.on -eoloq ieal ehanqi..in rUft-
n iftlJ ..t..,..eoeyst...~bj~'"to hydr.-.,_"'l~nt and buildi",of
~ir ......tart~i n 1'1\.
S ince then t.h4 r.""lts he".r~\d.rily Men pubUaMd tn t.h••n PIDJItCT,w·TtOJll 8ULLETtllS.TM •••ri••consi at. a taday of 24 title•••nd ~r••r.
planned i n tM ..er f~ure.Th t a ~nt .t o ..re t"'"1000 ,.,...far too IlUCh
t o ..net an l',)f t.t.oM who wt .h to -"Jft lK*It in f o~ton -on our doi",a .It ..a
t lMN f or.ct.cilhfl ee ....a Q')ll'tl:ti on o f t hlt .~r '••fr~.-::h bull",i"
wh i ch eould "'r.eon".n ient ly blI .."t.t hrOllqh tM ..U .
'!1Mo bu ll.tina ar.w ittlt n i n IIorW"1 'an.byt wit.h E",l hh •.--ri•••tabl....-ad
f iq~re e~i on ••r a~l l .t i n s 1- 1 ar.e-eept i on.).TblI ..ter ial 98tlMr~"ill ~
s yat ...t iMd a nd proeeas.-:J i n "'a d ~.e"lft tlt.t a f')ftr a lOf'lll plI r iod of ti••TM
..rt ••"ill thttr.fl',)r.eont inue aa l onq .a t~r .is int.r••t ,,,,~rel•••nt
..t.r ial ••a t leb t.f or pub l le a t.i ~.
t ~add it.ion to t he -tnfor..t.ion a ~l llttin .-.th. re ia ..ter lel •••ilabl e in the
for.of .cad••ie th....r -hovedo ppqa v@ r·).art iele.in i nt . t nat ioftal jourftala
and record .o f P f ~'nq.ff~.~,~•••ete ...f.,ene••to ..te,ial .
r . le.ant to t he "ir Pro j ect ar.li st ed at the .nd of th i s aurvey.
Th.fina l r .port.lJivlnq a ~l.t.p r •••ntati.">ft of th4 r e.~ lts o f the "ir
Pro ject.wi ll bIlt pu ~liSh '"by t M E rI .i f~n t.l .nd La :"heapinq ~r~nt at
t he ~-Wa t er 'esou re ••Oi r .etQf a t e in t hlt "fi ••POMER AND THE EMVtNC Ni.
The a b0ge _n H oned p..a~li c at lons wi l ',be d U tr lbuted trIM o f eha rqilt.bu t thiltre
ar.only a l1 :11 it "101 n~::-t ..Qf .ach ',n n a b l ••sa.t o f ttM>f.por t ....y be
'....ts.ued if n.e••ur/.
I t auat b4 p?i"'ted out ttl.at 54 .".f .l o f the nports i n the M rt ~s a r.only
partial.SOIM ...r~t""'P"rary a nd he "later ~n r.plae"by newr IIp-dat..-t
4'd l tions .T".uur i d ....y be u sed f rM ly a "lonq as the eopyr iqht.aet and
l au CClt r.rere nc.ru l ~s ar.r ••pected.
!'he "'ir P'rojeet.
Th.!nv l ron-entel and Landscap inq D4lop.art_nt
~JE -_ate f Re sourc ••D irector.te
Mi dd.lth~naqt.l'
OS:.D )
!toOItIIQT tel.:01/4'.1 00
~~
Project lead4r
•
O.'u.l kt o v"!r o.U'k IOl![ W iIl t O!l o k ali t @te r -.J r.r.ran•• t il
~P -I nfor ...)one {[t a v~~~nde l ocal i.tet .
T h ~l oc ~t i on Qf t he d ifte rent re •• •r ch ar•••with r~f .r.nc••
to t nfor ..t l ~n Bulletin ~r••
j
(
i,.
/..,
'..
'.......
•
----_..--.........----.._.....---
•L......---
7
T"""-d'i
····..
R
N
0 - -
------'
•
,il "11...'at .1""
l ~fo ~ti on bul le tin no.1.~1 .....
Th 's ,a the Uut l'~port i.tM -lrtfOC'-.ttOft se-rt.-r,.tIIIt _l~
Pro j ..:-t ..It s u n ey.tM or '9'"of tM pro1et:.I t ....18".rwt ....
aift htut l on .It lfOea on to .1ft •"-1'111 _eclrtptlc.of tl-.1ocaIItt_.'_
f or in t ,.,at iona ..t tM at.rt of tM pro~'n lin•..,.......
..,.r ..e 'C ~..nJ ..-ewfWlt i n ai ..and _I.adlldted "Ue tn ,fOlIt'-._..
r"po rt '.,f or tho..r ••.etM .not ~let.ly ....t~...
I nfo r ..t i on bullot.1n ru .. 1 aleo cont.i.,..•tkhnlc:.t deel:rtptlQII aI .....
••ir _r e nd £1'1 ellplAINtiOft of the t-.c....'C'.l t.~\Ia.I i n cocaaetl••l t h
t1'11 ,.t y pe r tr 1IC't.Ion...
,a..o.t ..r .,~dr opollMr de..,.lc.-nt p r o j ect r ..",lt .t n tM redur:t:lon of
....t .r ti i n (i-".r8 aM st re_ .".._r ..tuctiOlM ••ey \11:.-1y.The ~LOII
&11 '(~r e l y not Lc e .lbl ••01'i t ..,r.~lt i n •COIIPl-.:e .fer••Stnee the
Ina.t ~conat.r uction o f l ow ct _.croaa d ri ed-1oIP rh.r..........qu ite
C~.By ..jut"",t M s ,..r .tr ly conat ant ..ter leftl c ..be _htUI 1,*.....
t houq t\In.....te r t nput is "ini ..L,The..coMtr..ct.1orw ....C'a11"_In._1n
h.av.~..,..........a "inv a lu.&O l e tool f or 1 .nd sc ~l nlJ i n coowwct ion _it tl ~rn
t1 y.Jropowe r ,Je v e l ~n t p r o }~s .a nd ••ot 1M ]....r_i.....l'6 -100 _in
'wve bH>rl tkl i.1 t o r a r.i n the p ldlnnlnql s t~•• •
In t he ~inni nq o f the 1,10s l i t tl....t ~~poe.ib l l i t i .~.nd
U _lt ation.f -bi otope Ad jll.t_nt.-.The !nvi ro ...ntal ....La.ndec:~i ",
Depa r t ~n t o f t~Mat er ~aourc.s Dir ector a t .(MYE )tao«t he i n it i a ti ¥e to
e-s t a blis!l ..r e-s e ,ltc h p roJ « t c a lled -"hoIr weir ProJ~-.It ...fiM~tJr the
Cone.u i an 'eu P'LlnoJ .,,!'l i c h ..-.de LI p o f f ...~id by all hydr~r
1.veloper s.
~n.~ir Pro ject i .1~~l l ~n ~,ste .p ro ject where -ll ¥i~and
non-tivinq ·p races u s .lie s taoJied toqlMtr.r .The eMrllY n OlI i .follc-.d ttoa
the pri..r y prod ucers t o t op con.~r'l .?o do t his i t ...~""1'1'to .rY l,..
t ~••ter ~u.lity..._.a s Ll rv. ,of tn.~w.t ic ~nd t.rr..tr lal ~at i on
a lonq t he r i ver .:~v e s t i q a t e t he ~nt and qu.lity of t he d rif t ,c.lcul at.the
qr ~h .nLl trition.condition.~ua l ity ._iqrat i on .-ert al ity and popu1at i~
J ens i t i ••o f the f ish .nd 50 on .
In dddit 10n ~n ana lysis o f how people &Ct~l ly u ••t he r~u~.t~r i.-rs
f o r r ec r ••o;iona l pucpoM.J s "CtI ..5p)r t.fis hl nql IUS c .r r i ~out._~r1MM1
o t Col t.M'l .nd trout 1n willt . rCQ,lr..s ....r .they occupy the ..-l oc.Ut i e.i s
JI1 ~.t piIIrt o f t he p r o j ect .l ilt ..l ..A SloI r.-y or t he bird U t .illlon9 r l ..l'-
.t r ~t c he s ti lt h .nd "i t ~t.weirs .
~lt.oq.ther 11 l ocili l i ti e •.I I' .i nclud ed i n the "i ~Pr oject p l'uqr .....Tfte
n'~r o f r .~.r c h l oc al it i es ...kept t o a _i niau.t o i nSloI r •• •~fr lc ienc
q.oq raph i c v .~i a t i on a nd to c • •a oo-ple t.-betore-under-atter -~nce
o t cause and .t f .ct r e l . t i ons hip.
T he Me ir Pr oject .a ::ill C'OOPI'rac.lve p roj e...'"'t.bet...1ll the U n i "~s i t y o f 0 .10 .
t he Un ive Ulty o t'h r ""n .'rIM DiI'Kt,or .te t o r Mlld l U .and 'l'e.htMter Fi a"
(DVF)and MVE -_.t e r ",olol rc••D i~ect o r illt e.S ine.i t s conce pt i on .t he project
h oi'".ad .:he t o llowi ~St..ri ftlJ ee-i ~t",
Pr oj ect 1e -.:l er ,M nio ~e ftlJ i neer P 1 1 "'e 11qu i .t.'eVE -"'c.e~a..ource.
Director.te.
Dr."r ~.,DvP'S 'iab .....rch Div i sion.
Se ni o r e ftlJ i tMer "ateln Aai -:s.lIYK-MI,ter RellOU rce.Direc;:t o ~iIIt ••
~.s.pr or••~~..l d. r aorq ~tr ...t ~~t i t~te f oe !n .i r ~n t .l ~aq nt ,
TIN IIOr wq i a ••Aqr l cult.urilll Colleq', .
Dr.Tor 8.Gun,.r -.l.OW".IIyrdrqpower .....reb Cr~.
Dl ~ect.o r l nut o.e RU1.....,lIft-tliltec "ac~ICc:e.Dir~or.c.e•
.....profe ssor ao.ld Lar ..ft.Ioolo9 1c.l ........Uni ..r.i.ty o f Bergen.
Dr .Pett.r Lauson .Iool09 icilil ,.......Un ive ra it y of "r~ft~
Dr.~lbert Li ll.......r.Zoo 1e.l
•
In'-LIn ~PAIn'S Of'TIll:RIVEII:IlALLIJIIGD&J S"LVl'DUltIIlG TIll:PU.JOD ....1.
M"'10 1.AUGUST 1915
Jan lIII ich..l ..n aM Vl990 ...,1976
Infor..t ion Bullet in no.2.],peg••
The wb ~.ln.I n the Rlver hll1nlJdalnlu in Gol ....to hoi'"posh,1..b io-
1091cal 8 1qnl fl canco for ..n~r of b ird sp4Cl•••Th.re "f.15 prl..ry
apecl..r~btered 1n the UllPle an••ducl""the pltrlod fca.1 Ally IJnti1 'I.
AU!fuat,1975••of thlt ~1••had pre.loualy inhabited the ..tercouue.''Il1O
of t .....,ttM ..nard (Ana.pl.tyrhync~)and the 900under (II..rqu.
"f,.n..r l.showed ..definite preferenee for the we ir bastns,while the ap-
paelte v ••true of one of the two r ...i nl nq S p@Ct .f .the d ipper (Cine-Ius
cinelu.).Dippers were obs.ryed .ast o ft en I n rap ids a nd whlt...ter .1'••••The
fourth spec i ••,the C "i undp ipltr (Aetltua hypoJeueoe).hid no cl•.,bio-
topic pl'.ference.The other speci ••l nc l lMl .-d I n ttl,prt..~qroup ..ee found
on ly in ...11 ~r ••Noet of these ot her birds "1'••'qrants or .eqrant s .Of
the other priuty sp«'ies.two birds i n the dllCll t_lly~the t.al fA",..
crecca)and the qoldeneye tBuc.~.~la cla nqul a) .Wlr.observed to preter the
weir basin t or feed ing and rest ing.while the wad ~"9 bird s wet e fairly eypnly
distributed throuqhout the var ious types of r iv~r b iotopes .Two rat~r
urw;::-,species.the Il ingfisher t A lc ~att Ms 'and the ql'lty weqt.lil
t'lotac1l 1a einer.a ).""',..bot h ob serve-<!a t we ir b.,.i ns.As f or the secondary
species.three kinds o f s".allows (Hi r u ndi n i d a ~):tt;.barn swallow (Hirunda
rust ics).t he hou....rtin (Oe lichon urblca l .and th ~sand urt in (~lpar ia
r iparia).used the weir bas in ar.as f or fe~lnq f ar ft~re often than [~plds and
watertall ateas .
A ca.pati80n ot larqer area s o f the r iver c ou r se vh 4re weir bas ins alternate
with rapids to at••'with only rap ids show@d tha t:.U ~bird !.t.was richer i n
the atea.with welt 3.Ow lnq to d if ter ence"r n topoq t.1phy and vegetation.~he se
ee-pari80ns ate not particularly val i d.~~yer.a s t~.r .ate a nu.ber of
uncertain factor s i nvolved .
10
1\REPO RT 8 l kD Ll !'E I N "NlMB£R OP WEIR BASINS ALONG no;KIVEll USlllGEDALS-
ELVA IN THE SU ~F.R OF 197 5
o t a v R,H ,8J ..r n "lllJ'l!l L-J<tIc o b se n.U 16
I n fo r ti Ot"l bull e ti n no.1,lit paqes
This r epo rt Sd y be v lPwed a s ~p re lis t na c y d e sc ription of t~b i rd l l t e arou nd
the ba s ins u~1 ~t l n y @ ~t i q a t l o n .A v ariet y o f l oca tions ~ro studi ed :n a t~l a l
b l g t ns .r i ve r pool s 3nd a n umber o f aan-.ade weir ~sin••
scee of the b ird s pec i e s [eJisterN ,we re o b ••ryed only dudnq t MU
s i qr a tlons i n t he s p r i nq and fa ll .o r a s d ispers. l- reside nt b ir ds i n t he lat e
s u-.e r .T h e COlWIlO;l sa l'\d p i ~(..nd the waqta il are definite ly quant itathely the
~st l ~por t Jn t s~i e s .and are e ve nl y dist ri but ed alonq t~ent ire wa tec-
cOtJr se •
T~Lac ..o f s t l )du~s of p r e- de veLopIlIent p r o j ec '~b irdlife i n t h..ace••i nvolv@od
.a..~~i t d i fficu l t t o eva l uat e the effects o f hydr~r activities on b l rd~.
T h O!'IU t l!'rtt l ava t t a e t e a ce a no t p ro vide a s uff ic i ent basi s fo r a ny conc Lusion li
~bo u t tn ~.l qn i fi c ~nc l!'o f tne apparl!'n tly mode s t b i rd li fe ~r ou nd en!!'aan--ade
~i r bd s {n ll .
11
TftE TIWJUT POPULATIOfII IN THE RIVER .-rtJ{EOffLA.BU'ORE THE CONSTRtrrlCil or _tItS
Reidar &orqstr...1916
Infor..Uon Bulletin no.4.29 p.q••Is..also Infor..t.hx.no.17)
StJllMARY
In the River Markedela.a tributary to the River ~rd.l••lv.i n SeqR .".tarr.
Norway ,the water flow ha.blte...cons iderably reduced due to the l-.pounclllltnt of
the Lake Eldre.atn.In the u p pe r part of M~k~l.Ifca.about l~lQ to 1115 •
••••1.)the water flow ..y now vary fta.n••rly ••ro to ..vera••l,s.To
incr....the r iver surface s a-...i ta wil l be con.tr~ed.and i n this eon-
nection the popu lation of brown trout (5. 1-0 trutta L.)ha.been studied.with
spec ial ceq_rd to popul ation al •••The study w••carr ied out fca.Auquat 1"5
to A..agust 1976.
The year cl.....1915 a nd 19'6 were not c a U9 ht or obs.rved during .l~ro
fishing in the Upp@t part o f the r iver.and pro~bly the recrult..nt ha.
feiled due t o the r@duced water flow.
The fiah surv ive i n cer tain s ect ions of the r iver where there i.still ~
water even at .in iao-flows .and i n two o f these seetions the population was
est iaated by ..ans of .ulti p le aark-recaptures.In section T 4 .l.ettofishinq
w••used for f ish capture,wh ile in section T ~~electrofi.h1ng wa.ca.bilMd
with q 111 ne t tinq.
The nuabe r o f trout bl>tween u a nd 18 C1I was e.tiaated on four oceasi~.in
section T 4 .The est iaates var ied fra..bout 1.9 to 4.8 fish/lOO .2 .In
s ection T :ZA INlt iple aark-recaptuns were carr ied out twice for fish between
10 and 24 e-.The efttiaates qave population denrities of 3 .0 and 3.7 fish/IOO
.2.As other sections of the r iver had even lower densities or no fish at
a ll,the total flsh populat ion c f Merked_l.has to be considered ••tte-ely low .
With no recr uit..nt the nu.ber of trout will pr~bly decline rapidly du.to
natural .artal ity and fishinq .
!'he ,const ruc t ed we irs ..y i ncreaH the prodl.tCtive area ot the river .nd
prov ide .are favourable conditions ior the trout,with the condition ~h.t
recruit..nt i ...i ntai ned by stock inq.
12
PO ~LA TIOIIS Of'rot."!lIG SA:JII)N "-'liD TI'iJU'T 1-'THE liIl'IJU S K.J'OIIV.KP'01tE W XLD ntG 01'
..lIS
T9r G.~~~r~.t .1'77
Inf o ,..t lOft 8 ~1 :.t l "no.5.12 peq••Is...190 In t o r ..tion no.19 1
S U,..'RY
~r i~r S c i ~~.r Na rv ir.i n 50ft ne t n Norwa y ...i n i t s ~t ur.l
~itio n ..t yp i ca l ql ae i .r ·f ~cl..t.The e .t c~nt .r••of appra.i..tely 1'0
__2 •••r~~t o IS .~i n connect ion .t t h hy dr~lectt ie eaplo lt.t ion.
The power p lant .a.ea.p l~ed In 1976 .S k ja..now rece ives only the ~t ural
r un-o t t t ca.t he r ...i n i nq of the c .tc~nt a r •••Since the run-off t r oe the
q l .e i e, s no l onqe'ente'the tlv.'A 1 1ft.,.n!d i~h.r9*~t.rn.i ncre. sed
.at .,t .~r.t ur .i n .u ~r and reduc~t ur b id ity are "p4Cted.
T n.r ift's.,~has fla h popuht ions of ••t-on (5alaJ Mlu L .t .t rout
15a 1Jlo t.r ut.t .L .).c nar (S. l"li n o.J s a l p in",.I..).flo under ('l aU eh e ",.ne sus
I.. )a nd '!<!l (4.."Iq'.1 i U ."',(p i l h I..'.T tl.~l.t ti.o n .o f trout .",1 char a t.so
f a'bel i ~t o ~a .ixt ure o f s t at ionary a nd a nadr c.oua popu lat i on ••The up-
st r e •.aft_nt o f tM u la3nia ••are stopp.d by Li Uera UK Nter ra ll ~rox .
1)".t r a.~M l,.t :Ja ~y a nd a pp rox .J7 .a .s.l .
I n o r de r t o p.e t t l ~'COlllP!'nsa t e ttM d a -.qe and i nconw ni.1"IC4'c a us4d by t M
r ~uc:t1 on i n ..te r f l o..5 -e i r ,a r~p lanned ~at r e..Li llera l let .Two -e 1r ,
..r ~r in i s ~i n I t 71.
TM scopo!o r t Ms i n ~s~i q a t.i on i .t o qa o:.Mr inro ....~t lon on how t he younq
ut.or..trout a nd c har rekt on t he c~nqeod env iron-ent.al f~or s qenera Uy
~nd t"'~hu i111nq or lIfIl!'i rs i n par ticu lar .
T h ~st ud y so r a r h a s .~t hat t h~~."y ~l r l y i nc r e .se in l e nqth i s
M arly 2.0 ell f or s aL..".and te Nt i n ttl.f ust ,.al'5.a nd wit h a .Uqhtly
t-.t t er q r owt h 1n favou r o f the trO<Jt i n t he fi n t per iod .fter ~tc h1nq .
The qu t cont ent .hows t hat the trout t o •qr.ater extent t ~an .al80n f-.d
on .u rr ~i na.et ••T ~ut..»n on the ot.her h and .hows •qreater tencMncy t o
f ~un dri ft ing ~ua t ic i n sects (l ar vae l .
A~raqe ca t ch a ft e r )e l ~r o f i sh i nq per i ods w.a 6 f i .he.pr o 100 .2
(. a x.21 .4.s in 0 . 6 f is hes p r o 100 .2 l •T h ~f is h popu l at.ion i n every
l oca lit.y wa.u tiaatiN by Z1pp in·.[1 ' 51).t hod .Accordinq to this 7)•o f
t he s t and i nq c r op was c a uq ht wi th th.ti.hinq IMt bod ...us ed .and ...e nd lIP
wi t h a e a l c ~l a t ~fi .h-den si t y o f 9 p r o 1 00 ~2 .The de nsity c a lc u l.t io n s
al 50 indica t e s ~h a t h i qher den ai ti.s i n tM up per parts of the .~l.cn
contai ni ng part o f the r i~r.
The r "!la tiV"t p ropo r tions o f tM fi s h ..t er i al tNS U . )•ul ~.56 .0 •
trou t.1 .)•char and 0 .4 •~l .A.a rule .we c auqh t a les..r p ropo rt i on 0 +
s .al -m a nd t r ~t ~r -.d wi t h o l d er "f ear c l ••..,••The r ea son f o r th is .-e
bo!tliev~.i s d uO!to t heo .~l eet.iv l!effeet o f t M e l ..-::t d c a l ~u1 p.-n t .The
"s t i ~t ~effiC iency o r 0+s a t-on a nd trout wa s 0 .24 and 0.27 r ~.~t ivel y and
0.46 a nd ~.4 )f o r 1••Th@ d iffe r e nce i n .f f i cie ney on .a ~a nd t rout i .
s-a l l ~nd w1l 1 not i nfl ue nce the re.ult ••wh i l~the diffe renc e i n .f f ici .~
f o r di f fe rl!nt f i.h- .i ze.a re l a rq e and he nc~l n fl ue noe t he ,••u lt ••T he e st i-
..t ion o f fi . h den.i t ie.a r e Yer y r ouqh a nd t he c alc ul.t i on.e nc ~be ra ted with
i naccu r.d "••Con .ld ed nq thlltse f ac t or ••tM •.-pl1nq IMthad.u. ed in S _j c.s
t "!nd 1 t o unde r es t iaat e t he f is h d en.it les .
u
1II1QIIA'fICM ,JIOIIOUnCM SID.GJDft'II MID -.rRt.-T or'lac-TIIIOUT (SA'.A)'rf1lm'A.Zo.'tW""UVEa aSIWZIl&LSILVD .ftSTERN NORIMYf NPOM MGULATIOII or TIm
alVER
AoIild Lilt..n,1977
Infor..t lon Bullet in no .6.]1 ~••
Su.\RY
The Eks lnqedalen ri vet 1.l ocated 1n Va.ad al .approx .54 ....of a.rqen .The
t l ••r lost t~upper pa rt s of the c.tc~nt at••i n 1910-7)due to hydro-
.l~ric .x ~lolt.tlon.B4fore t~r ~u l .t i on o f t he ri ver tOOk pl.e.,a
thorouqh b iolog i ca l in...t igation •••carr ied o ut i n 1'67-69 by the Depart-ent
of looloqy.Un ive rs ity of BerCJ~.The s a ..loca U tles u.now the bas h of t M
"irpro 1~ITe rs .elpros jekt etl.~r.t he qoa l i s to i nve stlqate t he bio-
log ical effects of requ lat ion a nd w@ lr-bu ildinq.
Thi s PAper present s fis h d at a (fa.1961-69 l •••before the r.gul.tion .
In the Tref. l l a rea 4 sp..ninq populat i ons based o n t he recapture of prev ious
taeJ9ed f hh can b@ r ecogn i:l~.One o f t hese are Mig rat o ry ,the ]othe rs
s tationa ry .In the Ek••a rea there are 1 -ai n s pawni nq-popul a ti ans .on e
concentrat inq its spawn inq i n the u~r r eaches o f the ri ve r.the other
spawn ing i n the lover parts o f the Ekse a re a.
The s exua l i ...t ur.pa rt of the popu lat ion is a s st a tion ary a s the eorre-
s pondi ng s pawn ing pop u lat ion .
The recru it-ent a ppea r s t o be exe _llent i n ~h e T refa ll area with a populat i on
bet...n ]0 000 and 60 000 fish .In the Ek se area t he r.cru it-ent appear s t o be
poor with.popu l at ion o f hardly .are t han 1000 f ish i n 1968 .
Terresula l insects consti tute about SO t o t the fis h nu tr i ..nt .The other
half ts -a inly -.de up of s t onetlies a nd ~idqes .At T refa ll t he t er rest ria l
i n aects e onst itute o nl y a bout 11 , with .s ~h a .4 S ,ehi ro ~ids .Th ~
erustaee.he re appear to e ont ri bu te aboot S t of t he food.At Meahei.the t ~r
reatr i.l i nsect s ..ke up nearly 41 t.while the e r ustaee ans .nd the
ehir~i ds e ac h con st itut.s about 20 t.Mayfl i .s and c~die s f l ie.a re nowher e
a ~inant part o f th8 fis h d iet and 98ne ra l ly constitute S-7 ,o f the food .
In total about 40 ,of t he nutri-ent i s o f t err.str ial or19 in ,while 60 t is
produeed i n the water.Taken i n to eons i der at ion that perhaps SO t of the
nutr i ..nt for the latte r is of t err.s tr ial o r igin,about 70 ,o f t he fis h
nutr l ..nt wa. i n 1967-69 i ndi r ect ly a t erre.t r ial product.
.4
-'GZ.c.JIfI'H .ST'QC'I:1':AIm 1'I EUJ or _'I'IIJUI'.8 uwa ....u,....L'PI••'"Ittt QDL.
IUT'-'
P. r .....ss .1t l 1
l nf nr ..t ion B~ll.ti ~no.7,41 p.q .'
T two yi. ld f b rown trout .....ti_t.-d in t.,~lone of tbt M.~r...,lfted
Rive r N.IIlh nqd,d M l v.The ir ecr•.,.._I'e i cle ftt ica l ,but:t.,diU.red in
t e nqt h.t op<Jqu phy ..nd hyd roloqy.TN upper Mett.....Itt........abella.with
.inl .......,.t ~r flows i n wint er and .~r of 1.'.,.,10 .l/Me te.,...eU..ly.
The l owe r 0fM0 •.a .c a l.nd de~witb ,.-.ell qr••ter _tar-flow.!'M total yie ld
in 1977 was ut t aatad t o 1-1 k9 /t..fo r the'upper ....to Ie-II ""tw1 for tIW
l owe r Met ion .The rwatwU C.aUCf ht on e.et'l _fa wr.,-.cit t ,tNt the
••n we i.qhot o f trout c .".q ht i n the '*PPt1'MeUon ..only ~Ofte half of
t h t i n t ~100 r .Rod .....t he cta.iMnt....s,only.-.Uq ible l'r~iOft of
t he c a t ch WU a.w.by IM!'t s .Rod fi she r. "~id .-bout UOO day .idta to .-:h
A<lCt i on .nd t M>...".t.-q.e iltct'.pe r U S rlIi nq ct.y w.~trout.?IW l nd ...i d ....l
c at ches Y ~r ied .how9ver.q t ••t ty .
TM ya,u 's p l anti nqa f L'Ifq.al -s i aad t r out 1Wi..,..1....fetyrn.o f tG-SO ,..A
IJilU l t lve cor e e t ..U on ~...n t ho!'l e nq th of stodled fish a nd rate o f recapt ure-
l!'ll u ts .e f t he r <ItC a pt u r .s we t e -..de with in f ........but.t he t i_l .aq
W.ll &eoee e t a e ed "l t h tM ti_o f a t ocd nq .P I_nt irl9 i n e.r ly .~r ".....,r •
•~n J l .tr i ~t i on o f r et ~rn••T he wi nt e r ~rtal i ty o f t~~r ...1ni nq pl a nt ~
f la ~••ceeds thdt o f the l oc.l trout bV )- .l i ....~.i9 ~ .t iOfte of tn-
s t oc.ed t r out ~r e i n "eneta.ve ry s hor t .
TI\e wil"trout c auqht i n the llppe r section ..r.Oft the oIftr.,.you....e tholn
trout tra.t he l ove r one .poe . i b ly d ue t o the hacdllhlpe of Oftcwinteri",.
',s ~i nq r eod uces a y e .r c l •••he.i ta th ird .~r on••Itd the c . t c he.eon-
,iat s u in l y o f fi s h )-S y e us o l d.T he aqe o f 7••u:out ...r .d e t ....i lMd .nd
~o ne wa s o .d~r th..n 11 y ••t s.
T hoe q rowt h ..,a s rJlpi.d .The y e . ,l y l enqt h l nc '....nt:of tM 1-.ture U ah .....o n
t M a "'e r.-ql!''\and 6 c en t i _ t e r a on t l'w u ppec ..nd leNec aect ion re ~i..ly .
The .u lII!'r .-qe .:ond l tion f .-e t o !'a were e I o ..to 1 . 0.but h 19 ....t on the l a.er
sect i on wh er e a l ~..~r ...t.r f r ~tion o f t he trout lOftgec t~n 2 5 ceftt i-.ter
w...r~·f le s~.
Ol tter lll!'nce.an f U ll q rowt~..nd qua U t y -..a.t M d ue to t ....f ood a i tllat1on .
wry..5 00 ,w ~l t ..yfUes and c add i..fli ea t ot..U,ctc.ilYted the .t ...ch can-
t ent a o f the trout c . uq ht on tM l owe r section .~cpMnt it1 e . t e n ....a l so
1 re ..t eSt on t ~l a p a r t o f t he ri..r.
IFUSilGA1"C»IS or 1'IIIt aUilW ftmIA or MCU'l.AftI)RIvas,WI".fEIAL PlIS
01 aLACI...n.IIS,(DI PnM ,StJm"IIDU:)
Jan I .....t~,1.1.
InforNtion Bull"-i n no .I,'2 pelle••(see aho InfQr.-tion no U ).
5':"'"
T.r".lproe j.nu'.I n...tlq atl0ft8 In 1915-11 uc I nt.ftlIJM to .....Il _of
the que.ti~wh ich U IM I n conneet:IOft with the buildl",of ..In In
....Uy-r-.:Julated r 'INu to ..int.in tbe pre.IO\I._Ur 1 1.'I'M ..In p.rt
of the r ....rc h Is being curhd out In "-.h .,__len ftOn ..-t of"I'''.,and
i .ol'q.n laed by t he IooI09 ic.l lIIu onheraity of ael'arc~Oft bot...
tc.f.uIM at t ht;10:»109 i c al 1IIu i n 0.10 act:s as ••"WI_at to tM 1......
...t iq.t i ons i~Berqen .
on..&I ..of t ....~n thos st ud ies .r.to fi nd out tl"htt:bel'thel'.....dUf.ll.nee.
I n the bent hic ~nI U••aboge .nd below _Iu.and wbet....u tbe buUdl",of
..I rs q '''••1_II.r .f rect .i n r l ..r . i n d ifferent .Il••••IllDet of tbi.~Ilk i .
belnq c .rri@d out I n t M Ri.,.r •..-dal.llg.n rtluth of ROhqJber,(.......Ilud).
Th i.prol i_ina ry report .Iso i nc l ud. s r.sult.frc.I n ...t i,ationa I n the
rhers R.lll"lJd....1Y.(Bus k erud ) ."-1'..ed.l.(SOqIn OCJ rjolrd.n.l.Gl~(lied-
"I'k l,R.na.lva (H@d u l'k),N••(Sm -TI'IMde I A/J ).nd SkjOUI (1IoIld"ndJ.s.t.pl••
o f black-fl l ••f r a.Ek .inqed.l s.lv.(Ho rd. l and).re also ineluded.
The ..i n .-ph••i.I n t h@ ~nt hos s t ud i ••i s Oft black-f li••CS~llicJae)
bee.UN techn iqu••f or •..,11nq t h is qroup ue .1~le,and becavM _.lre.dy
Mft obMn.t l on.which i ndic. t e •connection bet...n the build i",of ~.nd
.n acc.....l . t lon o f b lood-suelinq b lacll-lly apee l •••SMlpl••u ..bMn taken by'
co llect I nq n ones .nd br usb lnq t~14 r.-ove .U the .ni..la.Ttlls -.thad is
..Ieet h e,and .s U ..t .s of benthos .Hl be beat ree 51-..1Ud..,l-.art.tIt
q r oups of Ch l r onoaldH ,.nd c . r t .in !~ropt.n.So f.r,the ..telll.l ee-
c.ived fra-Berq.n o nl y i ncl ud ••drift s.-pl•••nd botta.•..,1••t.ken with •
"~l e r fol'soft s ~bst r .t ••
tn .11 , I I b l ac.-fly spec i.s h.ve been i d. ntified i n the .1'•••i n..ati,.ted,
.nd 14 o f t M "ha;ve been found I n N~.hl.n .1n..,tiq.tiOM hel'.are
..I nly l i_ited t~the .r ••bet ...n Redber9 .nd Mor.f jord,whel'e four ..lr'of
r l ..r ..t.r ta l .nd blasted r OC"Ni..been built .5..,1••ha...1so beeft t . ". n
.t 10 st.tion.ove r •d iat .ne.o f lO It_fra.~ber,to _11 below IIollefjocd.
The l1 f e-eyel. ,o f •blaell-fly s pecl. ,Ni..biNn i n...ti,.ted by .asur l",t iM
body I.nqt.hs of I U VH co llected d ur i nq 1976.
The lire-eyele stud i .s .how th.t I ~i ,conveni.nt to d l.tlnqullh two type.of
blac..-fly .pee le.I n Mu-ed.lsllqen l aa-e spec i.'~r.lnt.r .."",.nd
ot hen ••loin...r oul'o f the siJlll spec i ••which O'l'ellwint.r ••eM'ha ..only
one q .ne u ti on •y ••1'1 Pros i ....l1-.f.rr"'I .......,Cn!pI!i.f1l8Clp!"Eul..11_
ClIn.na .nd S i_d l ...rc.!St u t _.S l ....li _r!pt.na .nd S .tuberc..be..t.c)
q.~r.t l ons •y ••r.The l i f ecyc l ••t ud ies I nc l ude two ~ie.wh ich a.erwlnt.r
as 1 a r v a~1 ~~~al.1'1.n:!u si~u1 1~7ern~s a nd S lsu li ~orna t ua.I t app4a r.
that S.or nat ..-d4ft lops t hr..qe,..utlon••ye.r,wh ile E...rma .....to
ha 74 ona 1an.rat i on.~h e l arva.of Wh i ch deve lop v. ry I lowl y.~ad ult.o f
~s~s p4eies ea4r1e i ~3 une-J~ly.bu ~l ~i n••o f S.rapt an •• S.tube ro,u.a nd
s.o r n.a ~1.lS al so fl y 1:'\Septe..eee ,
~~~~n h1qh e r ~nehos 1 ens i~y va '!?U nd 1n N~a1.1~en 1 ~197 7 than 1n 1976.
I n J u~-3 ~11 1'77 ~p ~o 7S0 O~O a n l ~l s /~2 ~r.to u~.w ~1 1e tha hlqhes t r e-
=ord~1.ns 1 ~1 1n 1 9 7 ~vas 70 000 a n1..1./~2 i n ~1-J u n••8Lac k-fl ie s
d ~ina~~••~~..de ~?a's '~h a s 99 ,of the aateria1 i n ~y-J U 1 Y I the
.~1.'S i .~1 1 ..repta ns a nd S.tuberol U2 -.re -est n~r~~I .On a vereqe 7S- 15 ,
of t he r ...1ninq ~nt hol va.Chi r ono-ida••wh ~le Ep~roptet.at t i ...
co n.~1 tu~ed lIP t o 50 ,.The den.itle.of t he ..benthos 9rou~..re .1110 fou nd
to be hiqhe r i n 1977 eha n i n 1976.S~c heck.o f the ..ter ia l fra.1978 I Uti-
q.at t hat t he de n.ity o f black-f l i es in June-Ju ly ~,even l ower than in t he
....period in 1976.while other 9rouP.o f be nt~....to ha .,.a »Jt t he la:w
d ens ity i n 19 7.a . in 1977.
Saaples froa 10 .tatio ns in Nu-eda lsl lqan i n J~ly 1977 show t hat the den lity
t)f t he bOttoa hu~1.stroft91y influenced by'the ..i tl.Th1l was ~st obVi ous
tor bl ack-f l i .l,which dom inated a t outlet .tations.At the..,t here were
aYe taqa de ns it ie.ot up to 160 000 a ~i ..1./.2 ••nd '0-90 •o f t he ..ter ial
wa.b lack-fli•••Bel ow the ve i l'area the den.i ty of black-f i t ••d.ereased
Sha rpl y,and a t the ....t i~the d.n3 i~~of C h ir~id..i ncre. sed 1reatly :
thi s .a.now t he domin ant 9roup.conlt it ut inq ~p t o as ,of t he sate rla l.The
e f te ct.of weir .Oft t he other benthos 1 roup ••re not .1 obv iou••••t hey were
rel at l ~l y poor ly r epresent ed.
~s t of the ..tari.l ftc.Iksinged.l.elva so far i s ftee winter .a~lel 'col
leet ~at Ik ..in 1975-7'.Kateri.l frc.the other loe.l it ie.~s eol1ected in
s ept a.ber 197 5 and/or July 1976 (Hal l ingda l.elva.M.rkadela,Cla.a8 and Rana-
e lva) .and i n J ~ne 1977 (Ne.).nd A\I9u,t 1977 (Skjo-al .
The dr ift sa~la.free !ksinged.l..lva show that )0 ,of the black-fly
Nateria l w••taken at the outlet It.tlon••It i.d ifficult to draw any con-
clu sion.frOll the bette.l.-pl.s,but black-fLies do not ....to be very abun-
da nt in t hi s r iver.The sa~appli es to Hallinqda1 ••1va and M.rked.la.In the
Se pt ••be r ...pl e.f tc.Hall inqdal.elva 7 000 - 20 000 ani..l./.2 were re-
qi atered.wi th a n 8verege of 11 000 ani..la/.2•N.arly .0 ,of the ..ter ial
was Ephe..ropt.ra.In July the denaity varied frOll IS 000 -240 000 .n1-.
..11/.2 •wit h .n aver~e of 100 000 anl..1./a2,of which 70 ,..r.
Chlrono-id.e .In ~rked.ta t he 5ept.-ber a ..ple.ahowed •d.n.1ty of 220 - 1 700
a ni..l ./.2 ,.nd .n aver4ge of 150 aniaal./.2 •The ..t er iat i ncluded SO ,
planktonic Cru. t acea and 40 ,I~ropter a .In the J uly ••.,1••there were
4 SOO -22 000 8ni..15/.2 ••nd .n averaqe o f 12 000 an1 ..11/.2 ,of which
80 ,..ra Ch irono-idae.
'.itly hiqh nUabet'of black-fli.,wet.found i n Cl~,Ren.elv.and Me••At
""l!'91.in Cl~U 000 .n iaale/1l2 wet.found in July••nd SO ,of t~
aaterial w••b lack-fli•••In "neel••CAtt••tr....n.,••000 ani..ll/.weI'.
r .qis t.red ,ne.r l y 50 ,of which weI'.black-fli...In the June •..,1••fra.
....140 ..IS 0 00 a ni&l le/.2 were found.anet 70-'0 ,of t h...wer.
black·fl i •••Tl .r.were a l so 1.rge nu.ber .o f C h i r o ~i d ..in Cl~(2 3 "
and i n Rena e l v ~(40 ,).
17
In Skjoma 3 600 - 9 100 an imals/m 2 were found in August,wit h a n average of
6 200 a n1mals /m 2•Chironomidae do minated,making up 65 ,of the material,
and were followed by black-fl ies and Ephemeroptera,which made up 15 ,each .
The black -fly material consists mainly of exuv iae,which shows t hat the
samples were take n too late 1n t he year to be representative .
The benthos fauna i n Num edals llgen i s ad apted t o the c onditions found in
he avily regulated rive rs.suc h as g reat var iat ions i n water level and periodic
drying -out of the r iver bed,and can be descr ibed as a ·catastrophe c om-
mu nity·,Black-flies a re well adapted t o su ch c o nd itions be c ause of their
short life-cycle,a nd the greatest c o ncent rat ion of l arvae 1s f ound at the
ou tlet from weir pools,where there i s a good nutrient supply i n the form of
drift .
Some aspects of the composit ion of be nt hos i n r ive rs wit h weirs ca n probably
be e xplai ned by succe ssion ;the short-term effect i s do mi nance of black -flies,
as for the relat ively new weirs i n Numedal slagen .At o ld er weirs,where there
is much more growth of moss and algae,black -flies do not compete as ef-
fect ively and Chironom idae and Ephemeroptera are more l ikely t o domi nate the
fau na ,as in Hallingdalselva .
The great var iati ons i n the density o f benthos in Numedalsllgen s how that the
commu nity is not very stable.Observations suggest that succession is occur-
ring as the blaCk -fly species ~~mu l i ~t~~r a t um i s inc rea sing greatly at t he
expense of S .r e p ~~Q!a nd S.tUbet~~~.In Renael va,where Eusim~~t~~~~~~~
was do mina nt,there were a lso large number s o f ~~_~~~~.This sp eci es was
also numerous at Heyegga,and d om inated i n Hall ingdal selva ,Me r ked01a ,Nea an d
Skjoma ,making up 40 -90 ,o f the black-fl y ma t er i a L
~l!!.!.Y!!...£l!!il~,:!,!!,§..!.!!!.~..H .!:!..'!repta'll!and S .r os~tat'!~are among the speci e s
wh ich are most troublesome fo r humans an d domestic an imals i n Norway, bu t it
is not known whethe r S .tuberosum,wh ich s eems t o be the most t ypi cal speci es
in we i r areas ,i s o f any impoit;~ce in thi s c onnect ion .The s o-ca l led -Tune -
flua-(Simulium truncatum)kno wn a s the main pest spec ip-s i n some d is t ri c ts ,
was a lmost ent i;;lY'-';lssing f rom weir a reas , a nd there i s little t o s uggest
that the situat io n ne ar ve t r pools gives rise t o any s pec ial black-fly probl em .
,.
TROUT,BURBOT AND BO'rI'OM INVERTEBRATES IN THE RIVER NEA ,CENTRAL NORWAY,BE-
FORE BUILDING OF WEIRS
Arnflnn Lang eland,Trond Haukeba ,1919
I nf ormat ion Bul leti n no.9 ,56 p ages
SUMMA RY
I n 196 2 the r iver Nea ,in Cent ral Norway,lost the upper parts of its catch-
me nt area due t o hydroelectr ic ex ploitat ion .This h as caused a great red uction
in wat er flow i n the rive r.I n o rde r to compensate fo r dama ge caused by the
waterflow reductions ,3 we irs were built when the rive r was regulated .Several
new weirs wer e c ompleted i n 1978 .
Thi s p ap er p rese nts data from the pr eliminar y investigations of fish and be~
t hos in 1917 a nd 1978,before the new weirs were bu ilt .
Invest igati on s of the be nt ho3 s hoved that a wide variety o f a nimal groups was
r epresent ed,a nd the total de nsity of benthic animals in the samples was rela-
tively h igh . Sel ect ed s ampl es o f Ephemeroptera ,Plecoptera and Trichoptera
have be en ide nt ified t o Sp eci es l only a small number of common species was re-
c orded wit hin eac h g roup .
I n t he inves tiga ted ar ea of the r iver Nea there are f ish populat i ons of tr out
(Sa lmo trut t a ) a nd bu rbo t (Lata l ata ),and the former species i s dominant .
Yie ld fr om ne t s used in we ir bas i ns va r ied fr om 404 to 672 g pe r net-night .
The fish l ee c h (A ca nthobdella peledinal was a common paras ite on trout.
Fish c o l lected by e lect rof ishing was u sed to c alculat e popU lation densities
f or trout us ing t he me thods descr ibed by Zipp in (195 8).The mean values cal-
c ulated f or o ne - t o three-year old trout v a ried from 5 .7 to 83 .5 trout per
m2•High e st de ns i t ies were found just downstream of the old w~irs.
The tot al ga in i n l e ngth f or young t rout was calculated to 4.7 cm,9.3 cm, and
14.5 cm af t er g rowth was finished i n the first,second,and third year,re-
s p ective ly .
Nymph s o f may f l ies (Epheme ropt era)s e em t o be the most importa nt f ood item f or
trout .Air borne insect s were also i mport ant , e specially in Augus t,and lar vae
o f Slmu liidae may cont ri but e subst ant ially t o the d iet of trout i n June .
INPUT AND OUTPUT OF ORGANIC MATERIALS TO THE WEIR BASIN AT ElSE,EKSINCZDALEN
Torleif ~k e n ,Ar ne Fjellheim,Roald Lar sen,Chr i st ian otto,1976
I nformat ion Bulletin no . 10,38 paqes
SUI9IARY
1.About 25 ,o f t he energy input to the veir basi n at Ekse is account ed for
by pr imary production within the weir ba sin (moss and algae),and about
75'by energy from external s ources (allochtonous material).
2. Di ss olved o rga nic material ,DOM ,constitutes 9 4 ,of the energy flow
through the basi n,but there i s no a ccumulation in the system .
3 .Coa rse part i cul at e o rga nic matte r,CPOM ,makes up 25 ,of the part i-
c ul at ed i np ut (POM ) , and 58 ,of CPOM is accumulated or transforMed i n
the s yst em.CPOM i s t her ef ore a very i mport ant energy source for the
hete r otrophs i n the wei r ba si n.
4 .The CPOM frac t ion e nt ers the bas in aa in ly a s s ur face d ri ft i n autumn and
as dri ft in the wat er mass es in sp r ing and 8u .mer .
s.Leaves,twigs ,g rass etc .domi nat e in the CPOM d rift into the we ir ba s in
l mo nthly mean 43 , 1 '):.ass ..d e up 21 , 4 ,a lgae 3 ,7 , and 31 , 8 ,was
un identified mate r ia l .
6.Fine pa rticu late o rgan ic u te rial ,FPOM,cons ti t ut es a8 .uch as 48 ,of
i n put and 50 ,of o ut put of part iculate o rga nic a at ter ,POM .The re i s
thus a ne t ou tput o f FPOM,d ue to tr ans form ation of c oar se par ticles to
finer hy o r ga n is ms i n the weir basi n. There i 8 a large net ac cumulat ion
o f FPOH i n t he basi n in a ut umn,at the s ame t im.as the leaf-fall,a nd
CPOM is ma inly t ra nsfo rmed t o FPOM at th is t ime of year .
1 .F i sh a nd be nt hos a lso c ont ri but e t o the net i mport o f part iculate matter
t o t he weir basi n.Thib o nly constitute s a small part o f the total i nput
o f POM,C, 8 0 /00 fo r f i sh and 1 5 0 /00 for benthos.The transport o f ben-
thos is nutr it io nally i mport ant for the fl sh.
8 .The flo w of organ ic ma te r ial int o and out o f the we ir bas in fi ts wel l
with t he model deve loped by F isher a nd Likens i n 1913.The equation
(I+P)/(R+E )~1, and t h e systell c an be r eqa rded a s stable with reqard t o
iapor t and e xport o f orga nic sa tte r.
9 .The re i s relat ively as .uch ac cumulation of CPOM at high a s at l ow d is-
charg es .The wate rflow is not a n iapo rt ant f acto r for the accua ulat ion
beca use t he we ir bas i n prevent s too au ch was hing away of o rga nic ..t ter .
20
A.S URVEY OF VEGETATION IN nut UPPER CATCIINENT AREA or '!lIB RIVER.D91NGEDALS-
ELVEN.WHSTERH NORWAY
Kacen Ska uqe Fredriksen,198 0
I nfo rndtion Bullet in no . I I,28 pages
SUMMARY
This r eport de scribes h1gher terrestr ial and aquatic veqetat ion i n t he uppe r
p ~r t o f Eksingedalen and Grendalen,from Eke.to lake Gr-ndalevatn,and 3180
higher vegetation in lake Trefallsvatn and lake Neshe imvatn .
I n o rde r to under s tand the or igin of plant material i n the drift and s impl ify
it o id enti fica tion,t he veqetat ion border ing t he r i ver was c lose ly s t ud ied.
The terrestr !al veqetat ion 1s ~ainly c ompos ed ot b irchwood,but cultivated
land.he at nland ,and boq8 also cover large areas.~h.r type.of woods a re o f
l esse r i_po r t anee .bu t s tands o f qrey a lde r (Alnus i nc~l!!) 'No["4Y s pruce
(Pice . ab iesl a nd other SpecL P.8 occur.The most i aport ant d war f Shrubs ar ~
heat her (Calluna vulgar is ).c rawbe rry l ~~~_~!t~~r od i t u.) .b l uebe r ry
l ,!!££i n iull Il!Y rtill us),·bllberr y",and boq wortleberry (~~~Il~'!-,!H.9.!..~I.
I n addition to t he ~e.d wa rf conel (Co rn u s s uecica l a nd var ious fe rn species
ar e i lll po r t a n t .The veqe t a tion o f the boq s fSdOiii nat ed by q UlIinlds and mosse s .
Th ~ar e as al o~t hl!ri ve r a re cOllnOnly c h.u act e ri s ed by a t hi cll:scr ub dOflll-
na ee c by q rey willows t ~ti..x g la uca ,~~.ta ppo nu :l I.Bo t.h t hese thicl(et s and the
c o mnones t types o f r iverbank veqetat ion ,i .e .c u lt i vat ed land d a.i na ted by
9 rass species ,n it roph11o us t al lherblleadows a nd bi rch woods c o nt ri bu te q r e at
amounts o f p l ant debri s to the water.
The hig her water veq etat i on is rat her poo r ly d evel ope j ,but some s p ec ies s e em
t o have inc reased t he i r ar ea s dur 1 nq the la st f ew years .
The r eg u la t ed l a ...e Grenda lsvat n geeliS to be without a ny for~o f l iving,highe r
veg et at i on .In Lall:e Trefallvatn a nd lake Neshe imvatn floating bur-reed
(~~~~~tu~4ngust ifol lull),bottle sedge (C a r~~_~s t r a t a l a nd water ho rse tail
(Eq uis et Uli flu~ttl e)a re q uant it at ive ly the most important,.speci al ly Fon-
~~~~tt~~teca r l i c a a nd ~~~h el y ~f a lcat a .In the ri vee itself,the mo s ses
c o nst i t u t e the geeat e st p aet o f t he f lo ra .Espec ially i apoet ant is Oi chelrma
t a1cs t a a nd s pec i es o f the g ene eal ~Qt!.Il!.!.is _1!I9.!.'!hypn Ull and Rh<!£.C!!i tcium .On
the ri ve esho res scatteeed s pec ies no rma l ly consider ed as spr inq-o r weed-
s peci l!5 grow .Yet ~~~ql~~_te p t a n s is found i n conti nuous aa ts .a nd i t sel!II S
to be ee Ll old apte-<!t o the v ar ia t ions i n water le ve l .
21
MIGRATION OF BROWN TROUT (SAL""TRtn'TA L.)IN THE UPPER PART OF THE RIVER
EKSINGEDALSELVA
Tor Henning Evensen,1981
Information Bulletin no.12,37 pages
SUMMARY
Migrations of brown trout were investigated around a weir basin in the regu-
lated river Eksingedalselva north-west of Bergen.The stretch of river s tudied
was divided into 9 zones:the weir basin is located in the lowest part of this
area,with stretches of rapids above an below.
The trout in the research area are small streamtrout,generally under 150 g.
and 25 em.The material is divided into age groups 3,4 and ~5 (fish in their
4th,5th and ~6t h growth season).Younger f i sh are not inclii'ded in the in-
vestigati on.
The year of research,May 1976 to May 1977 is divided into 5 periods.Mi-
gration is recorded a s recapture from the last place caught in o ne time period
to the first place c aught in the next time pe riod .
About 10 ,of the fish were recaptured o ut s id p.the area where they were
marked.Pew fish moved morp.than l km.during t he investigati on.
There are at lea st three more o r less separate trout populations with in the
area investigated,despite the fact that there are no physical barrier s be-
tween them.
A more detailed study was made of movements in t ~e immediate area o f the weir
basin.Male trout here become s exua l ly mat ure in age groups ] and 4,but
female trout not until age group 5.Approximately 50 ,of the sexually mat ur e
trout in this area,mostly non-spawners that year,remained more or less
stationary in the weir basin during the year.The rest of the sexually mat ure
fish migrated out of the weir basin early in s umm er and during spawning (in
october).Sexually immature fish in age groups 3 and 4 remained mostly in the
rapids upstreams and downstreams o f the wp.ir basin.Before or during the
spawning period these fish migrated into th e basin,but it is not c ertain
whether they overwintered there.
The results of this invest igati on are c nmpar ed with tho se of Larsen from a
similar investigation in 1968,before the river was regulated and weirs built.
In 1976,the trout i n the immediate area of the weir s eem to have become se-
parate from the populations further upstreams In the study area.The area
above the weir basin has become a new important spawning area since 1968.The
weir is not a direct barrier for trout movements in the Ekse area.
22
BENTHIC ANIMAL STUDI ES IN T1IE ElSINGEDALEN RIVEIt AT USE AP'l'ER REGULATION AND
WEIR-BU ILDING
Torle if B~ken,Ar ne rjellhei_,Roald Larsen ,1981
t nformat io n Bulletin no.13 ,41 pag e.
SUMMARY
A study of be nthic anl••1s has bee n carried out at Eke in Vakadal .uniclpal lty
north-e.st of Bergen,a.part o f t he We i r Project'.(Te,akelpro.jektet)in-
ve st igat ions i n the r iver E ~8inqedal••l va .
The -a t e rl al discu ss ed 1n th is report va.collected i n 19 76 with.suction ap-
paratu s speci al ly deve loped fo r the project.Benthos v a.col l ect ed ftc.3
local it ies i n the veir basin and 2 local iti••i n the ri ver outside the weir
bas in .
Ollgochaet a wa s t he d om ina nt group by weig ht a t al l l ocal it ies,and const i -
tut ed DOte tha n 50 ,o f the tot a l aYe'age b i a.••• •Chi r ano-id a.w••the
la rg.8t g roup o f i naect larva.,both by weight a nd by nuabe r .'or Epheaerop-
tera a nd Pl ec optera,biOM ass per un it area was low.r in the weir basin than at
t he l ocal it ie s ou tside i t .A divers it y analysis showed that there was a sig n i -
ficant ly hig her species d ivers ity of Pleeoptera nylIphs at the loca lity up-
str ea ll o f t he ~i [ba s in t han i n the ot her area s .
The local i t ies o uts ide the we ir bas i n had the h ighest total a verage b ia-asse s,
106.)a nd 11 0 .9 IIg d ry weight .-2 ,wh i l e the corresponding figur••for the
loca li t ie s i n t he weir ba .in were 4)8.2.589.1 a nd 434 .1 -:1 dry weight .- 2
respec t iv ely.
There wa.a h igher p ropo r t ion of b@ nth ic a niaals adapted t o slowflow ing water
1n the weir ba sin than i n t he r iver upstr...and d ownat re ..of it .A r educt i o n
of cu r r ent s pee d has phy siological effect a o n s o_e anLllal speries.and has
al so result ed i n a Much fLner s ubst r ate in t~e weir baa in than outside it .A
fine substra t e is ~re unst able and ha a fewer .ieroh.bitats than a coarser
substrat e i n area s with s tronger current s .su ch as t ho ••ou t.id.the we ir
basin.
2J
DRIFT OF BENTHIC ANIMALS INTO AND OUT OF THE WEIR BASIN AT !~SE
Torle!f Bakken,Arne Fjellheim ,Roald Larsen.1981
Information Bulletin no.14,37 pages
SUMMARY
1 )I n 1916 an investigation of drift of animals into and out of the weir
basin at Ekse vas carried out.
2)Drift samples were taken approximately every 14 days using 7 drift sam-
pler s at the inlet and 7 at the outlet of the ~eir basin.The drilt sam-
pler s were a l lowed to o pe rat e for 24 hours before they vere emptied.
3)During the year 24280.9 x 10
5 animals were drifting at the tnipt and
21792 .8 x 10
5 at the o ut l et .
4) For t he wh ole year,the figures for each group at the inlet to the weir
bas in were as f ollows (percentage o f total in brackets):Plecoptera
nymphs 74 .5 x 10
5 (0. 3 I ).Ephemeroptera nymphs 271.4 x 105 11,1 'I,
S imuli idae larv ae 41.0 x 10S~Chironomida@ larva@ 1136.2 x 105 ~4,1
II,Dipt era pupae 201.6 x 10 (0,8 '),Dlpt@ra imago 187.4 x 10 (0,8
I I.Oligochae ta 51 .2 x 105 (0,2 'I,Crust ac@a 21988.4 x lOS (90,6 I).
o t hers 32 9.2 x 105 (1,4 'I.
5l Taking th@ year a s a whole,only S imu1i ida@ larvae wer@ found in greater
numbers at the o ut l et than at the i nl et of the weir basin.
6)Nearly 100 , o f the Eph@meroptera nymphs in th@ d r i ft belonged to the
s pec ies Baet is rhodan~.From June onwards a greater number o f large ~
~odani nymphs dr ift@d i nt o the basin than out o f it .
7)Crust acean s dominated the drift from July t o Nov@mber.Most were plank-
t onic f orms,mainly fr om the genus Bosmina.Th@y o r ig inat ed from the re-
s ervoi r from which large amounts of water wer@ r@l@ased in connection
with repair work .
8 }Ol ig oc ha@t a were rarely found in the drift materi al,although th@y were
an important part o f the zoobenthos.The rev@rs&was true for Crustacea,
Diptera pupae and imago and Simu liidae larvae,and at c @rt a in times al so
for nymphs of Ephemeroptera and Plecoptera.These groups were mor@ c~n
in th@ dr ift than o ne would expect from their frequency in the benthos.
BENTH IC AN IMAL ,RODUCTICIrI IN 'nil:I I SI C"n.a.t EN RIVER AT USE A.P'T'!:R REGU t.\TI CIrI
"-"it)WE I R-BUI LDING
TOcle if a-«ke n,Acne P je l lhe i. ,~ld Lar sen,19 81
I nfo r ..t ion Bullet in no.1 5,32 p.qes
s """,,"y
As part o f the We i c p coject's (TeCSkelpcosjektet l i nvestigat io n s in t he c ive c
Eksinq edalaelva,..a su r e ~n t s of bent hic animal p rod uction hav e been e a cried
out at ) t ra nsect s i n t he we ir basi n at l kse and 2 t ca nsect s o ut s ide the we i r
ba s in.
The satec ial col lected was divided i nto g r ou ps wh i ch were ana lyse d by d i f-
fe cent a .thad s .Pcoduction o f t he e pheaecoptec an Beat i .c hada ni and t he
Pl ecopteran Ca p ni a pyq..e a was ..as u red by the ..thad of Winberg et a l (1971).
whi le fo r Oligochaet a production/bic.ass I P/Bl r at io.f raa t he l i t e r a tu r e were
us ed .The re.t of t he ben t hos wa.d i vided i n t o groups a nd pc od uct i on for e ac h
was c alcu l at ed usi ng the me t hod d eve lo ped by Hynes and Col eman (196 8 )a nd
Haailton 11969 1 .
The r at io between d ry we igh t a nd le ng th v a ci ed t coa g cou p to q coup.O@l nq
highest tor Baet is r hodan i and l ~a t f o r Di p te ra l arvae . The same wa s t r ue
f oc the ca t io be twi;n-@n;;gy c o ntent and l engt h .
Pcoduction was nig hest i n t he ra p ids u pst ce am a nd d ownst ceam ot t he we ir
basi n !), 8 <lind 3,4 9 d ry weight 111-2 y e ac-l o r 90,1 and 78,1 kJ 11 -2
y ea r -respec tive ly .I n the we ic ba si n the va lues f oc t he tra nsects wec.
2,0, 2 ,8 and 2,2 q d ry weig ht .-2 ye ar -l o c 44 ,9,61,)and 48,6 kJ m-2
y ear- I .
The .ast important q co up was Olig ocha e t a , wh i c h accou nted fo r app r ox illat ely 50 ,
of the tota l zoobenthos product ion i n the ar ea.The mo st i mport ant in se ct
grou p,Chi conolR idae ,had a high product i on rat e e lse wit h in t he we i r ba s i n.
For Ephe ..r optera,Plecopte ra a nd Sillluliidae ,produc t ion rate s were cons id er-
ably h igher ou t side t he we ir basin.
The hig heat P/B ra t ios (7.9 -8 .5)wer e f ound f o r Ba! ':.i s r hodan i ,wh ich i n
t hi s a r ea h a s 2 ge nerat ions a year .
Bent hic a n i~al p coduc tion was lowe r i n t he we ir ba s in t h a n i n the r iver o ut -
sid e i t because o f Chang es d ue t o the l owe r ed cu r re nt s pe ed:a lte red p hy s ic-
loqica l conditions ,and a ~c e ~eneous a nd l es s s t a b l e subs t r a te .
25
PYSlCAL AND CHEMICAL PARAMETERS AT THE INLET AND OUTLET OF nlE WEIR BASIN AT
BitS!,EKSINGEDALEN
ToIletf Baken,Arne Fjellhe im,Roald Larsen,1981
Information Bulletin no .16,JJ pages
SUMMARY
1)
2)
3)
')
5)
')
7 )
.)
')
101
Physical and chemical conditions were invest igated in the river Eksinge-
dalselva at Ekse before it was regulated (1967,68 and 69),and at the
inlet and o ut l et o f the weir basin at Ekse after regulation .
The mean water discharge for 1976,77 and 78 was 3 . 04,1.26 and 1.05.-,m 8 resp@Ctively.Water discharge va s high in summer and low in
winter .
The river was ice-covered from about November to May.Before regulat ion
(1967 and 68),the vater reached about lODe in summer.After regu-
lation (in 1971).water temperatures as high as 240C were recorded.
The temperature was low er in 1967 than in 77.
Before regulation the water was super-saturated with oxygen,while after
regulati on it was u sual ly s lig ht ly le ss t han sat urated.
The water was slightly acid (pH 5.7 -6.8).No c hange in pH was found
after regulat ion .
No s igni fi cant c hange was fo und i n c onduc t ivit y.Before regulation
values for conductivity (K20 )varied from 7 t o 48 ~scm-l,with the
highest values i n a utumn,and aft er r e gulati on from 10 t o 49 pscm-l,
with the highe st values in winter .
The c on centr at i ons o f Ca 2+,Cl-,NOj-N and P0 4 ]-P were me a-
sured before reg ulati on.No c l ear patt ern o f var iati on emerged.The con-
centrat ion of Ca 2+varied from 0.9 - 4 .2 mgl-l,that o f
Cl-from 0.7 -6.4 mgl-l,and that o f NO j-N from 30 t o 110 P9l-l.
The concentrati on o f P04 ];..P was a lwa ys less than 2 pgl-•After
regUlation (1976,77 an d 78 ),the c oncentr ati ons of the d ifferent ions
were highest in winter and l owest in s u mm er . The concentrat ion of Ca 2+
varied from 0 .4 t o 5.6 mgl-l,that o f Mg 2+from 0.14 to 1.1 0
mgl-l,that of 1 04 2-from 0 .9 t o 9.6 mgl-l,that of Cr fr om
0.4 to 6.4 mgC and t hat o f NOr N from 10 - 250 pgl-• The con-1 -
centrati on o f NH 4 +-N was normally below 10 pgl-l,and that o f P0 4-N
normally below 2 ?gl-l .
Th e transport of ions t hrough the we ir bas in was g reat est in autumn,
with up t o 60 000 kg month-l 504 2-.The maximum values f or o t her
ions were lower.
The highest values f or net i nput and net o utput respectively for the
different i ons were as foll ows:Ca 2+590 and 19 130 kg mon th-l
Mg 2 +1 30 and 2 210 kg month-l,S0 4 2-2700 and 2410 kg
month-l,cr"151 0 and 600 kg mo nth-l and NOj-N -217 and 59 kg
month-l•
The eff ect o f wat er d i sc ha rge on i on c oncentr ~ti ons was measured sepa-
2··Iratelyinsummerandwinter.Conduct ivit y and S04 concentrat o n
showed no c orrela tion with water d ischarge either in summer or winter .
The concentrations o f Ca
2+in s ummer a nd winter,and of Mg 2+and
N03-in w inter ~were l ower when water discharge was high.The concen-
trat ions o f Mq +an d NO j_showed no cor re lat ion with water di scharge
in summer.The conc ent r a t i o n o f C l-increased with increas ing wat er
d ischarge in bo t h su mme r a nd wint er .
26
THE POPULATION OF BROWN TROUT (SAIJ«>T fW'M'A.L.)IN THB KIVEll 14 Hi .....APTU.
CONSTRUCT ION OF WEIRS
Reidac Bo[9s t[0~.1981
Information Bul letin no .17,2S pages
SU MMAR Y
The br own tro ot pop u l at i on o f the uppe r part of Rive,Merked.la,a tr ibutary
t o t he Rive r ~rda l s e l v i .has bee n i nve st i 9at ed af t e'conetruetion of weirs
and stocking with brow n tr o~t fingerlings i n the weir baa in.Brown trout 1s
t he only fi sh gpec i e s in t he r ive r.
Due t o heav i ly reduc ed wat er flow the rec rui t ..nt t o the trout populat ion i s
c eased o r s t ronqly red uced.In shorter st re tch••of the r ive'~natura l
r ec rui tse nt occu r s ,a t l e ast i n ~e years,bu t wi t hout a t ocklnqa i n t he up pe r
basi ns the po pulat ion would ~we ve r prObably have been .xt inct.
In a~ust 198 0 SO ,o f t h e cont r olled fi s h i n the we ir bII e in.con aUt ed o f
Sl OC Ked fish .whi l e i n t he ru ns p r ac t ic a l ly no s tccked fis h was found.Th e
fi s h po pu l at ion i n t he r un s is e xt re me ly small o r t here i.no f ish at all d ue
t o l ac k o f water .I n s e ve ra l weir bas ins ho wever the populat ion are at such
t e ve t a s t o fo rm a ba s is f or a s port f ishe ry.I n o ne of the '-8 ir bas ins t he r'!
is '!ve n some qil l net t i nq .
The t r ou t o f t he ~e i r oasi ns ha s a f as t e r q rowt h rate c~red t o the 91tua-
t io n p rio r t o t he co ns t r uc t i o n o f we i rs,withow t any ..r ked chang.in f ish
1ens it y .Thi s i nd i c a t es bet ter q rowt h c o ndi t io n a ,and the .t r~h••of the
ri ve r wher e ba s i ns 3 [e f o u nd would p ro bably produce .are trout with inc reased
r ec r ui t a ent .
27
THE BROWN TROUT F ISHERY OF RIVER HEMSIL ,EAST NORWAY,1919
Per "a s s,1981
Informati on Bulleti n no.18,SO pa g@s
SUMMA RY
The yi eld o f b rown t rou t wa s esti mat ed on t wo sec t ions o f the regu lated River
Hems i l.s ituat ed a bout 600 m a . 9 .1 .The sect ions differed in s lze,topoqraphy
a nd hy drology .The upper wa s s teep a nd narrow with bed and banks of boulders.
The lower one was c a lm, wide a nd s ha llow with s tony and s andy bottom.This s e-
c tion a lso i nc l uded t he 11 m deep i nt ake d am of the power stat ion Hea.il II.
The c at chme nt a rea above t he dam 1s 77 2 km2 • The water flow may vary between
1 50 an d 5 m]/8 i n t he fiShi ng se ason 1 . J une - 1 5.September.Except for a
l oca l minnow populati on in the dam,br o wn trout i s t he only nat ive fish
s pecie s p r esent .Rainbow t ro ut ma y occ assional ly be stocked f or put and take
fishi ng.Rod f ishing o n ly is perm itted .
The l ower s ec t ion i s 3 .l km a nd t he a rea 41 . 8 ha o f wh ich the dam c onst itutes
16.1 ha . Th e n umber o f day ViSl t s was e stimated t o 42 00 and t he y ield t o 2 1 .6
kg /ha.Mo st o f t he fi sh was c a ~g h t i n the d am, wher e the c a tch was approx i-
ma te ly 40 kg/ha as c o mpa r ed t o 1 0 kg /ha i n the r iver part .A large share of
t he t o t al c at c h wa s t ake n i n J u ne,in spi te o f most angler s ar r iv ing i n Ju ly.
The mean dai ly catch,ho wever .varied wi t h the wat er fl ow,the fish ing be ing
at i t s bes t 2- 4 d ays af te r the cu l m i n a t io ~o f a spate .
19 ,o f t he t otal nu mbe r of fi sh c aught wer e be low the legal s ize of 2 5 e m.
Abo ut o ne f i ft h o f t he t r ou t we ighed mor e t h an 400 q a nd t he b i ggest one 4 .8l 5
kg.Wh ile t he t ro ut caug ht o n t he uppe r s ect ion had a mean ag e o f 3 .8 y ears
and a y ear ly le ngt h increment o f 5 e m,the trout o f the l ower sect ion av eraged
4.7 ye ar s a nd h ad a year ly g r o wth o f 5 .5 e m.Most poss ibly the d ifferences ar e
due t o the hy dr a ul ic conditi ons,t he g e nt le cu r re nt f avo ri ng sur v ival and
g rowt h and conseque ntly t he p roduction.Trout f rom the rapids had eaten ~re
su r face i nsect s than t he t r o ut fr om the c a l m par t,but i n bot h sec tions bottom
o r ga ni sms d ominat ed t he st o mach contents .In the dam,the sna ils and large in-
s ect lar vae o f the r iver were r eplaced by c hi ronomid l a rva e.
Th e u se o f ba its diffe red s o mewhat i n the two sect i ons,but t n all one half o f
the a nglers wer e using worm.On ly 15 , o f the anglers wer e fl y fi shers ,mo stly
u si ng dry f l ies.One per ce nt o f t he a ngle rs were r es idents i n the valley .The
Norweg ian angle rs were most ly l i v ing in the c ent ral ,e a st er n part of the c oun-
try,belonging t o 1 0 )d iffe rent u r ban a nd rural dist ric ts.The average d is-
tance be t ween home and r ive r was 221 km .One f ifth o f the a ngler s were f or-
eig ner s,mos tly Swede s and Danes.
One t h ir d o f the angle r s ve re sa t is fi ed wit h t he fi s hi ng and o ne t h ird not .I n
o rde r t o increase the c a tches ,the rive r has be en s t ocked wit h t rout of d if-
f erent si zes .So fa r,t wo-summ e r o ld b rown trout ha ve been no suc cess.Brown
trout o f c a tc hable size r eleased la te in au tumn have next season g iven a r e-
tu rn o f 20 '.rainbow tro ut 10 ,.where as s pd nq s t oc ked b rown trOJt has
gi ven a r et urn o f 50 - 60 t .
2.
P RES MOLT ATLANTI C SALWJN (SALMO So\lAR L . )AND BIKlWN TROUT (SALII)1'Itt1'T'I'A L .)
AFTER HYDRO-ELECTRIC DEYBW.-wr AND BUILDING OF WEIRS III 'fill RIVI'a 91.JtIG,
NO RTH NORWAY.
Tor G.Hegq berget ,198 2
I nfo rmat ion Bullet in no.1 9,10 pag e s
SUMMA RY
The Ri ver Skjoma ne ar Narv ik was origi na l ly a glacier-fed r iver.Due to hydro-
e le c t r ic power development in 1977 the river c hanged fcc.a s~tcold rive,
wit h turbid water to a su..erwarm stream with c lear water .
The p r esent s tudy s ta rted in 1976,and con t inued unt il 1980.The f ish was sam-
p l ed by elec trof lshi ng and the t o t al mate r ial consis t s o f 13 140 young a t-
l an t ic s almon and brown t rout .
The ~i m of the s t udy was to gat he r info rma tion o n how young salNDn and t rout
r ea c ted o n the cha nged e nvi ronmenta l fact ors g ene ra ll y and the e st . bH s hi ng of
wei r s in pa r ti c ul a r.
Dur i ng the r e search period the r e was o b se rved a n i ncre ase of f is h d ens i ty fro lll
a bout 6 f i sh/l Oa m2 i n I g76 to about 28 f ish /lOa m2 i n Ig80 .Salmon
c o nst i t ut ed 40 ,o f the tot al catch befo re KEP,wh ile i t const ituted about 60 t
i n 1980.The s har e o f 0+sa lmon a nd t r o ut was no t c hanged d ur ing t he re s earch
p e r i od .The d en s it y o f fis h was l ower i n the weir ba si ns t han at th ~s a mp li nq
l oc al i t i es bet ween t he wei r area s .t n t he wei r ba s ins t r out d ominat ed,a nd
mos t o f the f i sh wer e caug ht at locat i on s wit l}c oa rse s ubst ra tum.
The g rowt h o f the presmo lt s a l mo n a nd trout i nc reased 0.5-0.6 c m/year d u ri ng
t he r es earc h per iod .The reasons are thoug ht to be the general increased pro-
d uc ti v i t y due to r educed wat~r flow,reduced tu rb id ity a nd i nc reased water tem-
p e r at ur e i n summ er .The i ncrease i n summer t empe ratu res i s bo th a r e su lt o f
t he ho t s umm e rs i n Nort h Norway 1978-80 a nd the e li mina tion o f the gl ac ier -fed
p ar t s o f the water shed .
I n s p i t e o f the i nc r e a sed g rowt h l nd d e ns i t y ,t he prod uct ion o f s a l mo n and
t ro ut has no t bee n i ncre ased t o the S~~~d egree .Th i s i s d ue t o t he f a ct that
the pe rmanent v a eeeccve eed area o f the s t r" a m has be en r educed by at lea s t 1/3
o f t hat he fo re HEP.The increas ing share o f s almo n i n the ca tc hes i s ma inly a
r es u l t of a large r d egree o f .idat ream s ampl i ng a f te L .~P t han befo re.The i n -
c r e a s e of trout in the weir bas ins is a (t,s ult of the fa c .."h at t r o ut i s more
c ompet it i ve than salmon a t s t i l l o r s lowflowinq water.T he ~~a v i o u r o f s a lmon
a nd t rou t seemed t o c ha0ge i n the we ir basins .Between the weir s,the water is
f as t f lowi09 a nd the young salmon and trout a re oc c upyi 09 t err itorie s whe re
they a re feed i ng o ~d ri ft o rgan i$ms .In c o n t rast t o t he s ituat ion at t he re-
s e ar c h locali ties between t he weir s,tendenc ies of schooli nq was c e ee r v ed in
t he we ir ba s ins.
The s po rt f i s her y for s a l mo n a nd s e a t rout hav e bee n red uced t o a min imum
d ur i nq the r es e ar c h per iod,~a inLy because o f the obs t ru ctio ns f o r u ps t c ~am
miq ra to r s c reated by the low wat er l eve l a f ter H E ~••
2.
EGG PROOUC'!'IOtI,DENSITY.MORTA L ITY AND GIQII'l'H or BII:Mf TROU'r YOUNGER THAN ]
YEARS (SAIMJ TRlI'M'A L.)A'r US!,tlSINGEDALEN RIVER
Yngvar Ragala.198)
Infor..tion Bul letin no .20.47 paqes
SlJ*ARY
Population density,~rtallty and growth o t trout (younger than three years
old)includinq the total ltqq-production hav"been Invutigated in II tl!<)ulat4!d
river where weirs have been buil t .
The study area (560 ~aboY"s ea leve l )was d ivided into]zones.The welr
baa in (lone S)is s it uated between two stretehes of rapids (breeding are.s ).
Large variat ions was fou nd i n d e nsit y t r~zo ne t o l one.The zone above the
weir basin (zone 48 )h ad t he g reate st d ens ity wi th 68,6 fish ~r 100 .2 and
the weir ba s in had t he l ~st densit y wit h 1 .1 fish per 100 ••The dens ity
variati ons .u st b-.r ~a r d ed in the li1ht o f t he r ive r 's varying su bst ratum and
current c ondit ion s.
Egg-product i o n in 19 77 -566 ~qgs p~r 100 ,2 ~i n the r ap ids )~re than t wic~
that o f the prev ious y~ar (26]~qs ~r 10 0 ~).Ab noraal wat er flow is s up-
posed t o be t h~sa in c au~of t he l o ~~q -p r oduc t io"i n 19 76.
!gg--artal ity was f ound t o ~ye ry h igh -6 7 ,.Unsui t a b l e ice c ondit io ns
would see_t o be t he ~in c au s e o f t h is high ~g -mo c t a li t y .
Egg and fry acrtality f r OM spawn inq to two -month o Ld f ry ~a s 9 ]"b ut mor-
tal ity a.ongst young er fis h in age g r o up 0- 1 and aqe g roup 1-2 (Ju ly to Ju ly )
was also Yer ~high ,87 , a nd 61 ,cespec t iYe ly.
It is thought t hat de nsi ty-dependent mor t~l ity t og ether with c li mat ic i nduced
factor_were the most i mport~ nt mortal ity fac tors fo r young f ish.
The annual ~v~r 3g~qr~h fo e t he fi=st t hr ~~yea r s was 3 ,6 e m (4 ,6 gl .
10
DENSITY AND JlIORTALITY or BROWN TRtCX1l'(SAUl)TlWTl'A L.)OLDalt 'nAIl Z Y&AIlS AT
ElSE,EKSINGEDALEN RIVER
Toc fi nn F.An der sen ,1~8 ]
Informat i on Bull et in no .21,56 pages
SUMMARY
Thi s s t udy i s a p art o f the ·Weir Project-.
populat i on de ns it y and -ortality of brown trout ..re inve.tigated in the
regul a ted r iver Eks ingeda l sc lva north-west o f Bergen.The atreteh of river
s t udi ed wa s d i vid ed i nt o 9 zones.The weir ~.in U ••in the lower part of
th is area,wi th s t r ec hes o f rapid.above and below.Ther.are t~bigger pools
in the middle o f the a rea.
The trou t in t he re search area ace small brown trout,qene,a11y under 150
q ,and 25 CIIl .T he materi al is divided i nt o aq:.group.3,4 and-::-5 i n 1976
(fi s h in t he ir 4t h,5 t h and ~6th g rowth season)ar)(J the group.4.5 and ~6
in 197 7 (the g rou ps o f 1976 ~f t e r o ne year).Younge'fiah ac.not i ncl ud ed i n
the i nves t iga tion.but a r@ di scussed in connection with population fluctu-
a t ions i n o lder fi sh .
Com pa red wit h t he s it u at io n i n the area before r&gulation and weir-
bu ildi ng ,the pop u lat ion of older f ish was three ti...l.~9.r.In zone 5 .
r ap ids i n 1968 a nd weir bas in in 19 76,the population d.n.it~wa.5 to 6 times
la rge r .The we ir bas i n alone hosted about 50 ,ot the populat ion in tha wair
a r e a (zo ne -1 8-68 ;i n summer a nd early a ut WM 1976.
Less c OR ~e t i tio n be t ween big and small fish and better pos.ibilitie.o f
o ve r wint er i ng afte r the weir was built,is truly the .-in factors o f tb.g reat
inc re ase i n the po p ul a t i on o f o lder fi sh i n the l ower pact of the re••arch
<l r ea .
Gr eat d if fe rences i n fi sh d ens it y were found fra.zone to zo~,with
a bo u t 31 f ish/l Oa ~2 in un~of the pools and 4-5 f iah/IOO .2 in the
rapid s . The po p u lQt ion o f o lder fish was da.inat ed by the a9.group 4.
Summ e r mo rt a li t y was e xt reme ly l ow,about 5 ,.
I n d e s pite o f 6-7 months winter season with very sevare i c. s ituation in
t he r i ve r . wint er mo rtaLi t y was l ow.a bout 20- 25 ,for fish old.r than age
g r oup 2.
Lowe s t winte r mortali t y was found with in q roup ~5 fish.with about 6 •
i n the lowe r p a rt o f t he weir ba s in and about 15 ,in zone 3B-4A .In tha lat-
t er area t wo b igg er pool s have fu nc tioned as very good overwinterlnq place f or
o lder fl sh.
The h ighest win te r mo rta lity (40 ')was found i n group 3 f ish within zone
3a- 4A.Le ss d o minant fi sh.e x aap le g roup 3.overwinter in Ie ••good place.in
t he r iver , most truly peripher ial i n pools/baain or in the rap ida.Here the
i c e s it u at i o n i s e xt re me ly d i f f icult i n winter.and the winter MOrtality i d
co n 8 eq u~ n t l y q r@a t @r .
The wi nt er ~rta lity fo r s pawne rs i n zone 48-6B in group 4 was 36 '.
tw i ce t he mort ali O:y r ate for the a ge group 4 genera1ly.It Ilu.t be very hard
fo r a ft a h in 9roup •t o spawn.But s pawners in the group~5 had a mortal ity
rate o f the s am~si ze as t he q r o ~p g enera l ly.-
Cat ~8 t t O p h e mo rta li t y i n wi nter d ue to long winter s eason and very sever e
wi nte r condit i o ns i s p robably the _ai n mort al ity tactor t or b rown trout a t
Ekse ,e apec i a I l y f o e s ma lle r t is h.
31
THE BROWN TROUT OF THE RIVERS HALLINGD"LSEL~AND HEMSIL,EASTERN NORWAY,AGE
GROWTH.rOOD AND MIGRATION
Per A499,1983
Information Bulletin no.22,48 pages
SUMMARY
River anglIng f or brown trout is the most popular form of recreatIonal fishing
in Norway.Yet very little is known about the lite of the river trout and the
effects of regUlations and water velocity on life conditiona.Por this reason
the angling catches of different sections In the regulated Rivers Rallingdala-
ely and Hemsi1 were examin~d in the years 1973-82.The streams run trough
wooded valleys in Eastern Norway at altitudes of 200 and 600 a.ters respec-
tively.Both fast and slovrunnlng sections were included in the experiMent.In
River Hailingdaiseiv several low weirs have been constructed and in River
Hemsll a dam has been erected across the river bed.Brown trout and Minnow are
the o nly resident fish species.Migrating whitefish may occasionally be caught.
Angling exploits the trout from its third year of life and three to five year
old fish constitute the bulk of the catches.The oldest fish in the samples
was 13 years .In bot h rivers and through all years the mean age of the trout
caught was lowest in the fast running sections,the difference being about half
a year.During the year s the average age of capture increased,possibly as a
result o f frequent checks.Thus the proportion of undersized trout in the
c 3t ches decreased,but s t i l l the angli ng o f small trout represents a major
management pro ble~.
By Norwegian standards,the rate of growth is fast in all sections in both
rivers,the average annual length increment being 5-6 cm for the first six
years of life.The length to weight relationship is also most favourable in
c aIm water,the mean K-values being below and above 1,0 on the steep and
gentle sections respectively.Differences in age at capture,rate of growth
and condition factor lead to well-defined difterences in size distribution in
the various sections.
Trout caught i n the fastr unninq se ctions averaged only half the weight of the
fish from the c alm sections.The difference in size between trout fron weir
dams and runs within the same section is negligible.The biggest trout ever
caught in the experimental sections weighed 5 and 11 kgs in HeMsil and Hal-
lingdalselv respectively .
Roughly,the food of the trout i s very mu~~the same in all sections of River
Hallingdalselv.Different stages of mayflies ~nd caddis-flies constitute the
bulk o f the food.There is a tendency o f g r ea t e ~species variation in the weir
dams,and in the calm parts fre shwater shrimps may substitute for snails.How-
ever,the weight o f f ood f ound i n fish c e ught in a fastflowing section is
),
o nly half the .-DUnt ••ten in a slow-runn ing one.T~food .1tu.~ion 1n the
flowi ng part a o f Rlver K...l 1 ,...abl ••v~ry auc h the cond ition.of Ri Ye r Bal-
I lngdal ••l v. But 1n the I l k c.D..the ispor tance of the biq lnaect l a rv••i a
q r ••tly r educed ,and a t aq ••of aidqes d~lnate both bot t a.a nd a ur t ace foods .
In both rlvera .1 nnow a are of l ittle l -POr tance ••t rout food .
The qrow t h and food a nalyse.a nd t aqq l nq r ••ults i~ly t hat t he .i q, a tiona o f
t he ri ver trout a re s hor t.The q ua li t y d i fferenc e s be tween the s ection stock .
ar e thus not d ue to f lah ~y ...nt.but t o p hys ic al dif fe renc ••be tween the ..-
c tio n s .
I n Rive r Kalllnqdal a.lv •cal_section i 8 si tuat ed between two r ••trunn inq ..-
c t i ons . The trout a t ock i n the .lovrunning ~.t .r show.little ,••.-blanc.to
t he pop ul at ion.in the rapids,althouqh i t has the ....f low a.on of the
fast runn ing s ect ion••On the oth.r hand ,the trout populat ion.in t he two
s wi f t .ect i on.show a h iqh deqr ••of confor_i ty in sp it .of very d iff.rent
d lsc har q•••Th.l ndica ti o n.are that t he st r ...q rad ie nt 1.t he factor re.pon-
s ible fo r the qual ity var iat ion betwe en t he locaL s t ocks. The re.ults f r a.
Rive r He. si l s uppor t the c oncl usion.The hi~her wat er ve loc ity i a s uppos ed t o
reduce t r out l ong.v i t y,qrowth a nd cond i tion i n t he f aat er sect i on.I n ste.-
ainq t he c ar r.nt we irs ..y have a benefic ial effect,but t h.y don 't eli.tnat.
th.di sad vant aq ••of •ste. p qr adtent .A d a_~y.however ,tota lly c hange the
Living cond i t ions o f the resid.nt tro ut s t oc~.This ha ppened i n Riv.r Re.sl 1
~ner.t he qual i ty o f the t rout inc re a.ed after the i apound..nt of ra pid s.The
J ~~l&O .erve ••wi nt er i ng place for t he river t rout . The lnvestiqa tion shows
tnat r &g ul a t ed .t r ......y s ust ain via b le s toc ~s of brown t r out i f s ensible
al nl_U.flows and phys ical i ~r ove..n t .are c a r r i ~t h rouqh.
Jl
Ttl!EFFECT Of WEIRS ON MACROBENTHOS IN REGULATED RIVERS,WITH S PECIAL EMPHASI S
ON BLACI-FLIES (DIPTERA,SIMULIIDAE )
Jan E.Rustad,1983
Informat ion Bu ll et in no .2 3,98 pag es
Sl1t'MARY'
The main part o f t he Te r s~e lp r ~sje~t~t wa s c a r r i @d o ut 1 n t he Ek s i ng@ da le n
north-east of Bergen.Th is re se ~r eh o n the bo t tom fauna a ct s as a s upplement
to the investigations 1n Bergen.
The aims of the benthos s tudie 3 was t o find o u t wh et her ther e a re di f fe re nce s
in the benthic c omm un lt i t e s a bove a nd ~l o w we ir s,a nd wh~th ~r the b u ild ing of
weir s gi ves si mi la r ef f~ts i n r i ~e[s i n different a reas .
Th e mat er i al was c o l le ct~in 1975-7Q .Mn st o f t his work wa s ca r ried o ut In
the R iver Numeda l sl l qen nn rt~of K onq 5~r1 (Busk e r~).lnve st i qat ion s we r e
mainly l i_it@d t o the a rea bet ween R~ber9 and No r ef j ord .wh ~r ~f ou r w ~i r ~o f
r lver mat er ia l and b l ~sted r ock h a v~~e ~bu ll t.~ample5 have ~l ~~he en taken
at 10 statio ns o ve r a d htance o t 1 0 10:"11 trolll R0libo!rq t o ~ll b-low N.)ref j o rd .
This r e port a l so inc l ~1 e s r e s ~l ~g from i n ~e q t i1 a ~i Q~s i n t h~r '~er s E~si n 1~
:la15elva (Hor1aland ).H ~l H nq:hlselva (B..Js lte ru-t),M.a r~'!chd~(Soqn 0'1
F j ord ane l.A kr p.s t r ~~n in Rena I g~~3r ~l .H ~Y '!q q ~in Gl omma (M ~i~a r ~I ,Nea
(S e r-Tr endelag ).S lC jo l'lu (No rd lan-il an d S id bo t n ~l v a (T r0lll31.
Samp le s hav"!be en tak en by co llecting s tanes a~b r us hinq thpm t o remo ve ~ll
the an imal~.The mdin em p h3~is i n t he be n thas s tudies ha s be en o n blac k -t lie ~
(S lmul i ld a e).The mdte rla l f rom E k s i n ~~d al s elv ~.cans is t i nq o n ly ~f
black-fli es.a lso includes s a ~p les and bottom s a mp l ~s t aken wit h d s u r ~r
sampler a rd wi th a samp ler f ~r sof t s u bs t r a t e .
Result s from the stony bo t tOll'l i n Nu m'!'dal sl!gen s how h ig he r eff ld lency r .,r th"!
s tone- p ic king method t han f a r t he kic king me thod.St o ne pi c lting wa s ~s t f or
black-fli es and m ay fli e~,bu t a t eo q ood f or 'l tonef lies .cadrt i'lf Up.s a n<t c n t rc-
no1'l ids .
21 blaCk-fly spee t e e o f ~c.~~i.~~.<;'lle Phid.E:.~!.i.'!.'!.li!!!!!a nd ~i.,,!u~ha ve
be en r ecorded in the inve st iqated a rea s .Det a il ed desc r iption o f q rowt h a ~1
l ife-cyc les a re e sti~teJ by obse r va tion of la rvae and pu pae .
Mb st of the bl aclt-f l y s pec ies o v er win te r as eggs and ha ve o ne g e n e r at ion a n-
nually :~~qt!.i.'!'!H.'!'!.{.~tt ~l n t"u ?tl .~~_~~to PY 9 \m .Cne...etIt.a..f4'!~I pee ,C.t:.r_~
N t !..C .la~'1 t~~.Eust'!I!H'!'!-c:.~t{.~!.'!.l!'h £!:!r_!'!.'1~.h-'!.'!t~·-!,!.~£!!!H.lu'!.
Sl~ul i u ~noe llt"ri ,s .tr u nc~t u?tl.S .~u bla cus tre .S .~r a ~t~it an s a nd ~--_.__.-----.-.------ -----------------!2!.!.!~<!'!~.
J'
•
~ng t hose wh ich ove rwinter ••8998 there are t -o epecie.which .....to be
able to change between one and two generation.annually I ~iu.roatratu.
~~t~~!~.One specie.,s.tuberosu-,h••two s ensrat ions in N~.l.
ligen,wh ile it s eems t o be o nly univoltine in the other localiti•••
Four s pec i e s o verwi nt er as larvae.P ros i.uli~hirt!2!s h••one generation,
while ~t~~tt~~~~has two ge ne ration.annually.Eu.i~~liua V.lnu.has two
ge nerat ions i n Mum.dal.1Agen and in Eks ingedal••lva,while it h••only one
Qeneratlon i n t he ot her local it ies.SiauliuM ~nt icola may have two gener-
a t ions in Ek s ing edalselva ,but i s un i~;;ltlne i n the other localiti•••
Res ult s fr om Numeda ls lAqen show that t he de nsity of the botte.tauna i s
strongly i nf luenced by the weir s .Th is vas .cst obvious for black-tlles,vh ich
do mi nat ed a t o ut le t stations with 80-90 ,of the mater ial .~t thea.statio ns
t here were a verage d ens i tl es o f up to 160 000 ani..18 /.2•In a apot sa.ple
750 0 00 a nimal s /m2 wer e f ound .Below the veir area the density of
b lac k- f lies d e c re ase d s harply,at the same t i ..as the density of ch ironom ids
i ncrea sed q r ea t l y .
The bent hos f au na i n Num eda13l1gen 1s adapted to the condi tion.found i n
he a vi ly r e gu la t ed r i ver s,such as g reat variations i n vater leyel and pe r iod i c
d r yi ng o ut o f the r i ver bed,and can be deac r Lbed as a -cataatrophic COM-
muni t y-.Black -f lies a re well adapted to s uch cond it ions because o f the ir
s ho r t li f ~-cy cl e .In Nea ,Akrestremmen and i n Glo...,vhere s uch c ondit i ons
a re p r e sen t ,l a rg e c o ncent rat i ons o f black-fly larvae a re also found.
Bl ac k-f lie s s eem to ~l ess i mpor t a nt i n Eks inqedalselv a ,Hall ingda lselv4,
S k jo ma and i n S~i bo t n e l v ~.
Som e a spec ts o t the co mposi tion o f be nt hos i n r ivers wi t h weir s ca n probably
be e xp lai ned by s uc ce s sio n.The s hort term effect is a d o _inanee of
bl ac k-f l i e s ,as wi th the r el a ti v el y new weirs i n Numedalslagen .At older
we ir s ,wh er e ther e i s much more g rowt h o f moss and algae,black-flies do not
c om pet e a s e f f ec t i re l y and c h i r o nomids and mayflies are more li kely to d omi -
nat e the f auna,as i n Hallinqdalselva .
Re s ul t s f r o m Nu me da l slagen i nd icate that the s hort term effect may favour
typ ica l ou tlet s pec i es a s S imul i~m rePt~~!,which i s known a8 a s evere
b l ood -s uc ki ng s pec ie s .The successi on in N~dalsll~.n appears t o affect c om-
~e t i t io n bet ween S .r e p ~!,S .r o~~atum a nd S .tub!t~:.
The r e s ul t i s a s t r o ng r edu ct i on i n d e n s it y o f ~~-tePtans and so me rP.d uct i ons
o f S .r o s~~~~~~,while the dens ity ot S .tube rosum appears t o be stable o r
s lo wl y l nc rea sl ng .~t~~~~tuberosum seems to be a typical spec i es i n we ir
l oc ~l i t ie 9 .I t a ppears that the long t erm effect in Numedals lagen ,3 nd pos-
si bly i n the ot her l ocal it ies,is approach ing a more t ypical rive r ine s peci e s
c om pos it i o n with r ed uced i nf luence o f outlet species .Th is impl ies a black-f l y
fauna wher e known spec ies s eems t o be less l mport ant .
.
-~-----------------.
lS
PUBLI SERTE ARBEIDER MED TILKNYTNING TIL TERSKELPRQSJEKTET:
PUBLI CATI ONS WITH DATA FROM THE WEIR PRO JECT
Aas s,P.
Aass ,P .
Aa s s,p.
And er s en,T . ,
Fje llheim ,A ••
t.a r sen,R.,a nd
Ot t o ,C .
Ander se n,T.F .
Ander sen ,T.F .
19 78
1981
198 1
1984
19 78
197 9
198 )
~rr e t oq ecretf l ske i Hall inqdalselv&
ved Go l.
T ~rsk elpros jekte t.Informa sjon nc.1.
NVE -vassd raqsdi rekto rat et , 42 s ider .
Fisk og f is ke re 1 Hems tl 19 79.
T~rske lprosj e k te t .Inf orma sj on nc.18.
NVE-Va ss dr aq sd irek t oratet,5 0 s ide r,
~rr~ten i Hall inqda lsel va og Hemstl.
T~r skelp r osje ktet .lnformasj on nc.22.
NVE -Vassd raqsdi rekto rat et ,48 sider.
Ag e,g rowth a nd yie ld of b r o wn trout
(S a t mo t rut ta L. ) i n t he r t v e r Hal-
Ilnqdal se lv,ea ste rn Norway.Proc.s e-
co nd i n t o s ymp . r eq ,s t r eams .Ed .L il-
l ehamme r , A.and Sa l t ve it ,S .J .Os l o
198 2 (i n p een).
Re lati v~abund a nc~and f light peri ods
~f Ephemeropte ra ,Pleco pt er a a nd
Trichoptera i n a r egu la ted we st
No r wegian r iver .
No r w.J .t nt .Vo l .25 .pp 13 9-144.
Os lo ISSN 0029 - 197 8.
Po ~ula sj o nstetthet oq mo r tali t et ha s
er eee ,(Sa lmo t rut t a L.l i ev re del av
Eksi nqeda lselva e t te r r e gu1er inq.
Ho ved f agsoppgave i z oo loq is k 0koloqi,
Un iv.i Be rgen.90 p p.
Be 3t anJst e t t he t oq d 0delig het has
0 rr et (S a l mo trutta L.)eld re e nn 2 a r
i eyre de l a v Eksi ngeda 1sel va .
Ter s ke lprosjektet.Informasj on nr.2 1 .
NVE-Va ssd ragsdirekto ra te t,42 sider .
Behe ira,E .,
Jensen,K. W. ,
Mellqu ist,P .,
Va s sh aug,QJ .
Borg str0lll,R.
Borq st cam,R.
Balkke n ,T .
8 ~k ke n.T .,
Pj ~l l hei m ,A.og
Otto ,C .
B~k k en ,T .•
P j el1h~i m ,A.og
t .a r s e n,R .
8-'!kken,T.,
Fj e1lhe im, A.oq
La rsen ,R .
8<1!kke n,T••
Fje l 1 hei m,A.og
La r se n,R.
1977
1976
198 1
1918
1 919
1981
1981
19 81
J.
81 otopfocbedtlnq i requlerte oq
uregulerte laks evassdrag .
VN-ra p port nr.1,
NVE-Vas sdr a gsd ire ktoratet .2 9 pp .
QJ r ret be st anden i M0rkedela fer bygg ing
av ters kler.
Te r sk elpro sjektet .Informa sjon n r.4.
NVE-Vass dc agsd i rekto ratet,2 9 s i de r.
QJ r ret be st anden i M0rkedei a ette r byg-
9 1n9 a v te rskler .
T ers ke lpros jekt et.Inform asj on nr .17.
NVE-Vas sd r agsd i re kt o rat e t,2 5 s id er .
Vek st/L i vs cykl u s og n~rin g sr ela sj on er
hos Baet is rhodani Pl ctet IEphemero p-
ter a),Ca pn ia pygmaea,Zet t er ste dt
IPl ecopt era)oq o i ura nansen t .Kem pny
I P le c opt~r al .Hovedfags op pg ave i
ep e s te t t eoo t cqt ,u n tv ,i Berg en .6 0
pp .
I nn -og u t f~rse 1 a v o rqa n i sk mat e ria 1e
ti l t ~r ske lbd S ge nq e t v ~d Ekse ,
E k ~inged a1e .,.
T e r s ke1 pr o s j e ~te t .I nf o rmas j o n nr .10 .
NVE-V assd r aqsd i rekto r at et .]8 s ide r.
Or lv d V bu n ndyr inn l og ~t a v t ~r s ke l
bassenqet ved Eks e .
Te r s ke Lplos j ekt e t.I nfo r mas jon n r . 14 .
NVE -Vass~r agsd i r~k t o rate t.17 s irte r .
Bunndy r produks j one n i Eks i ngeda l se lva
v ed Ekse e t t e r r equler inq oq te rsk e l -
byqq i nq.
Te r ske l pros jekt et .Info rma s j o n nr.15 .
NVE -Vas s1 raq sd i re kt o r ate t,32 si der .
Fy sis ke oq k j e mi s ke pa ra met re ved i nn-
OJ u t10 p av tenk elbas senqet ve e Ekse ,
Ek slnged a1p n.
Te r sk elp rosjekt et .I n f o r ma s j Qn n r .1 6 .
~VE -Va gg drd q s 1 i r ekt o r atet .])~l d e r .
198 1 Gro wth pa t t~r n s a nd f ood h a b it ~of
Baeti a r hodani ,Ca p ni a pyg maea a nd
Diura n an s ~n i in a we s t No r weg i an
r i ver.___ _ _ _ _ _ _ _ _ _ _ _ _.....'li'erm Ht J?7 '
Bakken,T.,
Fje11hel m,A.oq
Lar sen,R.
Bakken ,T.,
Fjellhe lm ,A.
and Larsen ,R.
Bo'tkke n,T.,
Fje llhelm,A.,
Larsen ,R.a nd
Ot to ,C .
B.k k en,T ••
F j ellhe illl,A.
Jlnd La rsen ,R .
Evensen ,T .H .
Eve nse n, T.H .
Even se n,T .H.
F r ed ri ksen,K.S .
1981
1981
19 31
19 84
1 9H
1 981
1978
17
Bunndyr st udl er i Eks ing eda1se1va ved
Ekse et te r r ~q ul er in g oq te r skelbygging
Ter s ke1pros je kte t.Infor_as j o n nr.1].
N VE-V a s s ~r a g s d ir e k t or at e t,47 s id "!r .
Seasona l Fluctuations o f Ph ys i c al a nd
Chemi cal Paramet er s o f a weIr b a sin i n
a r egul at ed we st Norw eqi an r ivp.r.
No rd i c Hydr o loqy ,12.p p ll - 42 .
Vege ta t i o nal e ne rq y budg et o f a wei r
has in I n we s t e r n Norway.
"r c h .Hydr o bl <.)l.'H.p )51 -16 ').
Bent ir.a nimal r rod uct ion i n a we i r
ba ~i n a rea i n w'!'st er n N or w~y .
Pr oc.~eco nd l nt .~ymp .r ~q.s t r ~~~~.
Eri .t.1.1 I p.h amlll "!r ,,..."'00 5 d1t vei t ,S •.r .
Os lo 19 82.(i n p re s s ),
Van ,lrin~hos ar eee IS d N)t r ut t a t .1 i
a vr e d e l :)'J Eks i ng'!'dal sp.lvp.n e t t e r
r equ Le r l n j ,
Ho ve df a gso ppq ol ve i.s pes i e l l aoot oq t ,
Uni v .i Be rge n ,8 4 pp.
0rr e tvan .lri nq 1 e v t e de l av Eks ir),Je-
da I s "!1v a ,
Te r !lke l p r lJs jp.ktet .t nf orma !l j on nr • 1 2 .
N 'lE .Va 5 sjr olq s~ir eKto r at e t ,)7 s i d ~r .
"lo vt"'TI e nt !l o f t rou t (S ..J l lt'<l t rutta L.I
within a weir basin i n a r egula ted
river in wp.~t p.r n Norw3 Y.
Pr ee .~e c o~t int o sy~p .req.g t r e a m~.
Eri .Lill e hJlmme r .~.3nd S a l t v~i t .S .J .
Os l o 198 2 (i n p r ess).
V@q"!ta s j an sund e r s 0 ~e l se Oftkrinq 0yre
d e l av Eks ing eJ a l s vassd r a qet .
Hovedfaq soppqave i 0k oloq isk bot an ikk ,
Univ .i Ber q en.1 8 5 pp,
Predriksen,K.S .
Haqala ,Y.
Haqa h ,r ,
!i~9 ·}b~cg e t ,T .I';.
H eq q ~c q e t .T .G .
Heqg berqet ,T .G .
1980
1982
1982
1977
19 11 2
1 9 ~J
1984
11
Veq.t ••jon.und.r....l ..i ."r.del .v
!••i nqed.l.va.~r aqet.
Terskelpro.j.ktet .Infor...jon ne ,l l.
NYI-V.aadragadir.ktora~.~,2.sider .
Popu la.jona~et~het,eqqproduk.jon ,
-o,~ali~.~og vek at hos e f r et I Sa l ~
t rut t a L.)i .wr.del av Ek.ingedala-
e lYa etter r~\tlering.
Ho vedf . g .cppgave i zooloq i s k 0 . 0109i,
Univ .i 8e'9.n.111 pp .
Egqproduka jon,y nq.ltect het ,d ~.lighet
09 v_ka t be••net.y nqre e nn ).i f
'5al -o t rut t a L.)i WYre d el a v
Eksi nq edal . e lva .
Ters kelpro sjekt et .I n f o ~j on n t .20 .
NVE -Vas sdr aq adi r e.torat et ,47 sider .
aes t anden av u nq fi s k i d en l aks e f ~ re n d e
d e l av S kjo..f er byg ginq a v te r sk ler .
T~rs kel p ro sjek te t .I nf ormas jon nf.S.
~VE-vas.d rags dire k to r at e t ,~2 s i de r .
om lak.09 ~r re t i Sk j~e t t er
cequl er Lnq 09 ter skelbygginq.
Terskelpr os je kt e t.Inforaasjon n r.19 .
NVE -Va ••drag sdi rek tor at et.70 s i d e r .
Ha bi t at se l ect ion a nd seqreg at ion o f
p a rr o f a ece t c Cha re (Sa lve li nus
alpi nus).b rown t rout (Sal .e trutt~)
a nd At l ant ic a a ~(Sa t.o aala r L.)
i n t wo s t re ...i n no r t h Nor vay .
Proc .S~.on a rctic cha rr .~innipeq.
Canad a 19 81 li n p re.s).
Popula tions of pre.-olt sal-an (Sa t-o
s a l a r L.I a nd b rown t rout (Sa l -a t rut -
til.L.)be fore and af te r hydroe lec tr i c
de ve l ~n t a nd building of ve i.n in
t he r iver S kjoaa ,north Nor vay.
e eee,s econd i nt o s pp.req.s t re ..e,
Ed .Li l l .h....r .A.l nd S alt veit .S .J .
Osl·,19 12 (i n p r."),
Heqgberget,T.G.
an d John sen,B.O.
Hi ll"!stad,K.O.
t.ar ee n,R.
t.anqe l e nd ,lI,.,
Hil uk eh0 ,T.
"t"!l\qui st.P.
"l'!llqu i s t,P .
Me ll qu i e e ,P .
x et tq ut st ,P .
~''!ll q ll i s t,P .
1982
1982
1917
197 9
191')
1976
t977
1980
L981
t~81
'9
Infestations by Gyrodactylus sp.of
Atlantic salmon in Norwegian rivers.
J ourn.Fish 8iol.(19821 21,pp 15-26.
Tersk1er,vassdrag og 1andskap
IWeirs,watercourses and landscape)
Kr aft og mi1je nr.4,Marges Vass-
d ra gs-og e1ektrisitetsvesen,144 pp.
~rre tens vantiring,bestandssterreIse,
v~kst oq fAde i eyre del ~Y Eksinge-
da 1se 1ven fer regulering.
T ~r skelprosjektet.Informasjon nr.6.
NVE-V a ssdragsdirektaratet,]1 pp.
~rr e t,lake og b unndyr i Nea fer byg-
~inq ay tersk1er.
Ter sk elprosjektet .Informasjon nr.9 .
NVE -Vassd rags di rekto rat et , 56 pp.
Et b io loq i sk f or skn ingssamarbeide i
r egul er t e v ass tir a g.Ter skelpro sjektet.
VANK n r.1.NVE-V ass dragsdirektoratet,
pp 2 lS-2J1 .
I nf orma sjon om Ter skelprosjektet.
Ter skelpros je kt et.Inf orma sj on nr.1.
NVE -Vassd ra gsdi rektora t et ,47 pp.
~k ologi sk f or skninq i Vassdrags-
di r~k to r a t e ts regi.Ter skelpro sjektet.
Fos sekal1en nr .6.MVE-Vassdrags-
di rekto rat et ,pp 18-21.
For d eler og ulemper yed t er skelbygging .
VN - rapport nr.4.NVE-Va ssdrags-
d irekto rat et ,20 pp.
Fordeler og u lemper Yed terskelbyg-
g1 n9.Terskelprosjektet.
VN-rapport nr.5,NVE-V4ssdrags-
di re ktorat et . 20 pp.
Godt fiske 1 Hemsil!
Fosse kallen nr.8. NVE-Vass drag s-
di r e kto rat et , pp 17.
Mellquist.P.
Mellqulst.P .
Me llqu h t ,p .
Mellquist,P.
Mp.llq ul.s t,P.
Michaelsen .J .,
g e e ,V.
Ra a s t ad,J .E.
Raastad.J .E.
1982
1982
1983
1984
1984
1976
1979
1981
1982
.0
8101091 I.flerbrukss....nheng.
Rapport tra seml.nar om vassdragsfor-
valtnl.ngen I.Norge.NVE-Vassdrags-
direktoratet,pp 153-162.
8l.otopjuste r l.nq,-freMtl.dsoppqave tor
Vassdragsd l.rektoratet.
Fossekallen nr.7 .NVE-vassdrags-
direktoratet ,pp 17 .
Waterpower development i n Norway.En-
vironmental cons iderat ions .
Waterpower '83.Tennessee,USA (In
press)•
Landskapsple ie ved store naturl.nngrep
-Terskelbygql.nq.Utemil j0 nr .1 ,
pp 18 -19.
Tersklers innvirkninq pa va nn-
kval iteten.{I I va ssd rags-
reguler ingers vir kning er p a v ann-
kv al l.t eten.NHK-semlnar 14.-1 6.mar s
1984.8 ••• ••(In p ress) .
Rapport om takserl.nger av f ugle fauna en
langs d e le r av Hallingd al s ~lv a i
pertoden 1.mal.-t ,augu st 197 '>.
Ter ~ke1 pr o sjekt~t.Informa s j o n nr .2.
NVE-Vassdrag sd irektoratet,39 p p.
Bunndyrund er s0kel ser i r e g ulert e e lver
-med ho vedvekt pa i nsektg ruppen kno t t
(Dipt era -Slmu ll lda e).
Terskelprosjektet .Info rmas jon nr.8 .
NVE-Vassdr agsd irekto rat et,6 2 p p .
Blods ugen d~knott i Norg e .
Fauna 34,pp 11-16.
The Weir Pr o ject (Ter skelpr o sj ektet )
in Norwayl Inve stigations o f the Bot -
t om F ~un a o f Regulated Ri v er 9,with
s pe ci a l empha si s o n Black-fl ie s .
News. Br it.S illl ~l i um Group.Nr .6 -
1981,pp 5-7.
RallStad,J.E.
Rid,0 .,
Angell-Jacobs en.B.
1983
1916
"
Tersklers virkn ing pi bu nndyr i
regulerte vassdrag,med hovedvekt pi
insektgruppen knott (Diptera,Simuli l-
dae).
Terskelp rosjektet.Informaajon nr.23.
NVE-V~asdragadirektoratet,98 pp.
om fuglefaunaen 1 en del terskelbaa-
s enger langs Ekaingedalselva,somneren
1915.
Terskelprosjektet.Infor.asjon nr.3.
NVE-Vassdragsdlrektoratet,18 pp.