InteL'lJational Council for . C'. M. 1993/ J: 58 the boxploration of lJhe Sea ,. 11 Anad.comous ,WQ Catadromous l!~ish Committee SALMON FtI VERS Ob' "!L,; KOLA P3 HNüU1A. R.uPRO) TCflIIV'~ PO'l'El: (1'1 AL AND .sTOCK ~'lIA'lIUS 01" Nl'LAN'I'IC GALlION FROII (NiE U\1BA RIVER by Zubchenko A.V. and O.G.Kuzmin Polar Research Institute of Marine Fisheries and Oceanography (PINRO), 6, Iillipovich Street, 183763, Murmansk, Russia • IN'l'RODUC'l'I ON ~hc Umba River is one of thc lllain salmen rivers on tlle Kola Peninsula. I t is 25 km long. 1'he river flows in the meridianal direction from the north to the south along the break in the crystalline shield extended from the Voronya River through the Lovozero Lake to the coast of the White Sea. 2 fhe square of the Umba basin is 6.248,5 kru • There are 599 rivers of different lcngths (4.229 km on the whole), inflowing; in it. • 'l'he Umba is a river of a lacustrine ty~e. On its way, it cros:'5es several lakes of 61,1 km extent (49 % of tae total river length). '1\ he bigges t lakes among the lineaL' ones aL'e the Kan ozero (25.5 2 2 km. long, 89.6 l<.m ) and Ponchozero lakes (9• .3 lan and 20 km , correspondingly). Quite a large nwabcr of great lakes (the Vyalozero, Munozero and Ingozero) is situated in tne basin of the Umba. fl'he sUlD.!Ilerized 2 wa ter square of alllakes from the Umba basil1 is 807• .3 km • Coefficient of lake content constitutes 12.9 % (and 7.1 % in average for rivers of the Kola Peninsula). 2. • Ichthyofauna of the Umba basin and its inflows includes 15 opecies: Atlantic salmon (Salmo salur L.), trout!(~. trutta ~.), Arctic char (Salvelinus alpinus (L.)), cisce CCoregonus albula CL.)), whitefish CCorep;onus lavarctus CL.)), g~'()yling (1J.1h.ymalluo th,ymallus CL.)), pike (Esox lueius L.), jroaeh (Rutilun rutilus CL.)) ide (Leuciscus ~ (L.)), minnow CPhoxinus phoxinus (L.)), burbot (Lota ~ (~.)), threcspinc sticklebück (Gasterosteus I aculeatus L.), ninespine stickleback (PunBitius pungitius (~.)), perch (Ferca fluviatilis (L.)),- rutfe CAcerina cernua .CL.)).- In SOULe 'ycarß, pink salmon COncorhynchus gorbuseha (Walbaum)), adapted in the European North, come into the Umba,river. • Twelve species of fish are target spec~es for commercial fishery and e;ame: Atlantic salmon, pink salmon, itrout, Arctic cmr, cisco, • whitcfish, gray1ine, pike, roach, ide, iburbot end perch. However, "". thc most important commercial species is. Atlarltic salmon, which io ~hc target spacies for commercial and sport licenced fisheries. I During the whole period of fisheries onithe Umba River, measures have been baken to malee salmon fishery rational and reproduction . I of this speeies optiit!l.lllu. In the middle of 30-ies, a fish ha lichery I waS built with the same oim, ~hich still operates. ! In 1978, Ghe coneentrated fishery of salmon was introdueed on the • I eounting fenee of the Umba river, installed seme kilometers from the estuary. In 1989, fishery on the cOUnting fence was prohibited by the USSt{ Committee of Nature Protection, anti. by some other e organs. ~ater on, this decision was eon~idered as an error and eanceled. Nevertheless, it led to the complete desorganization of the existed sys tem cf exploi ta liion o~ lihe Umba salmon otocl~, cODsequenees of VJhleh take plnce n't pL'esent t and maue tllc proteetion • and works on reproduction more difficult. I Undoubtedly all thio, tObether with other negative fuctors, influenced more or lesn the otatus of salmon stock f~om the Umba River. fl'o evaluat;e this stn tus on the basis of ovailable uata is tne csin taskof the paper. 1U~ERIAL M~D' ~ffi~HODS Data of investigations conducted in the Umba basin in 1986-1992 are used, as well as archives of PIWlO and MUHMANRYBVOD (fisher.y statistics). Datu on squares of salmon spawning-rearing oreas (Kuzmin et al., 1ge9) we~e corrected durinG ~urvoys in 1991-1992. ~otal extent of routes constibuted abaut 183 km. Surveys on spawning-rearing areas (SRA) were conducted by methods of PINRO. Borders of SRA were determined visually, squares were calculated by topographie maps and by data of aerovideosurveys. The bottom is charaeterized by the elassifieation of M.V.Klenova (1931). To deseribe the YOllIlg salmon density of coneentration , the published • data (Kuzmin et al., 1989) and data, obtained by thc eleetro-trap in 1992, were used. The initial data for evaluation of status of . Mum~~mYBVOD • salmen stock in the Umba River were those of for the period of 1950-1992. At this, eatch statisties till 1978 ineludes data of eoastal fishery; data for 1979-1989 were obtained in the result of the direet aecount of coming spawners on the aeeoLmting fenee; and spawners abundanee. in 1990-1992 1s calculated by the results of thc control csteh using average eoeffieients of return anu survival of variaus year elasses, obtained fo~ salmon from this river in previous years. RESULTS AND DIDCUSSION According to PINRO data, total spawning and rear1ng fund of the Umbä River, 01' influents of the first ami second orders (the Vyala, Muna, Inga and Lyamuksa rivers)an~ of arms Kitsa, Rodvinga, Nizma • B~IShoi 2 und Krivets (Fig. 1) constitutes 4.477.800 m ; 1.909.700 nf 2 of thcm are spuwning e;rounds and 2.568.100 m ~ reari.ng grounds ((llable 1). 2 In the Umbn R i vor t ehe spawning-rearing areas occuPY 2.677.270 m , 2 including spawninp; g.cOW1US (1.041.950 m ). The most qualifie<1. SHA are situated nearby the Semiverstny and Kanozersky 'l'hreshoulds anel Zhemchuzh.ny Reach. , 4. , In the l\iWlO River (39 lan lone;), more than 1.t~ km are occupied by Sl{A. ~he main spa~ning areas are situated 20-28 km from the river-heau. ! 1'he bottorn of the spawnine; grounds consi~t of gravel and pebbles, current speed is 0.5-0.8 rn/ s, depths are; down to 0.9 m. 1 In ~he Inga River (it is an influent of the Muno Riveri 17 km lonß), I the main spa~ning und rearing aroos ure Dltuated in the area of 7-8 and 12-14 tan. In the Kitsa arm (6.6 !an long, it floVls out of the Kanozero Lake), spawning grounds are extended for 2.5 km~ In the Rodvinßa arm (7.3 km long, it flows from the Kanozero Lake), the main spawning grow1ds are situated in the area of 1-2 and 4-5 km • More than half of tue Nizma arm (15 km Iong;"it flows out of the • Rodvinga River and inflows into the Ponc~ozero Lake) is occupied by spawning grounds and rearing areas. The main SRA are situated in the areas of '1-;), 8-11 and 12-15 km. ; i In tae Bolnhoi Kriyots url.il (l~. 8 km long; l i t flow8 out of the Ponchozero Lake and inflows into the Nizma R.), SRA aie situated alone; the whole extent. On the tllreshoulds, which'are the rearing I " areas of young salmon, the bottom i6 mainly of boulders, current speed is 0.6-1.0 mls, depths are down to 1 m. On the bars, the pebbles predominate, current speed i8 0.6-0.8 mls. Noarly tne wholeextent of the Vyala River (38 km long; it flows • out of the Vyalozero Lake) is threshoulds (28 of 38 km). 'l'he total 2 square of threshoulds and bars constituc~s 380.000 m , that is a gooel potential for salmon reproduction~ However, due to O.G. Kuzmin et ale (1989), the prolongated exploitation of the river ror the timber rnfting led to the cbange; of a structure of bottorn biocenoses and to the domination of organisms, which are not the ! feeding ones for young salmon. Besic.les, in tte result 01' technical preparation for thc timber rafting (deeping, and straightening .of the rivar bed, buildlnG of dams and crib~)t the Vyala Hiver becarne a trough without sanctuaries for young s~lmon. Complete destroying \ of·the rivel' bed liquidated, to the opin~on of authors, the con- ditions for sulmon spawIling und roproduction {the lat;t;er takes place only in Dwall rivers, inflowlng into the Vynla River, and in tl~ influent of the Lyamuksa River). In the Lyumuksu R. (26 km long, inflows out 01' the Lyamozero Lal\:e an<l inflows into"the "Vyala), the tirnber rafting was stopped in 1986. However, there are still timber blockages an<i old cribs on tte threshoulds. Many rcmnants of bark are on the bottorn. I].'hreshould bottoms are prcsented by fined and middle-sized boulders and pebbles. Current speeds anu dep ths are the salIle as on the other sim.ilar areas of tele Umba. Studying of parr' 8 distribution derJSity on various areas of the \" river proves, that it varies sufficiently. Small densities are nobei 2 in tüe middle <lud low river (0.1-0.92 sp"ec./m ). In the upper river, the uensity of ~arr distribution i8 sufficiently lower (0.02-0.06 spec./m2). According tu uata of O.G.Kuzmin et ale (1989), the densiby 2 of parr distribution in the upper river did not exceed 0.06 spec./m in 1986-1987, whereas it reached 1.4 8~ec./m2 in the low rive.r; in thc Vyala , young parr were not revealed at alL in the studied areas; and in the Lyamuksa River (the Vyala's.influent), densitics of young 2 salmon distribution co:ns:t;ituted from 0.0035 to 0.107 spec./m • Due to the same data, the productivity of young dOWDstream-migrants from the Umba i8 equal to 2.78 g/m2 • Thus, due to Paver (1973), the potential production of sffiolts in the Umba can constitute about 2 691.600 spec.