Põlula Kalakasvatuskeskuse panus meriforelli (Salmo trutta trutta L.) varude täiendamisel
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Kuupäev
2012
Kättesaadav alates
ainult raamatukogus, only in library
Autorid
Haugjärv, Kerli
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Käesoleva bakalaureusetöö eesmärgiks oli välja selgitada Põlula Kalakasvatuskeskuse panus
meriforelli varude täiendamisel. Püstitatud eesmärk on saavutatud.
Töös kasutati Põlula Kalakasvatuskeskuse poolt aastatel 1998 kuni 2011 meriforellide
kasvatamisel ja asustamisel ning suguproduktide võtmise käigus kogutud andmestikku.
Meriforelli asustamist alustati Põlulas 2001. aastal. Kokku on aastatel 2001-2011 kasvatatud
ja asustatud samasuviseid meriforelle 310886 isendit, üheaastaseid 82496 isendit,
kahesuviseid 50619 isendit ja kaheaastaseid 63538 isendit. Meriforelli noorkalu on asustatud
Põlula Kalakasvatuskeskusest 11 aasta jooksul 16 jõkke. Põhilisteks asustamisjõgedeks on
olnud Pudisoo, Selja ja Pühajõgi. Kõik kaheaastased ja kahesuvised ning suurem osa
üheaastastest kaladest märgistati rasvauimede äralõikamise teel; kaheaastaste kalade partiidest
märgistati osa kalu ka Carlini tüüpi individuaalmärgistega. Kokku on asustatud Põlula
Kalakasvatuskeskusest jõgedesse 507500 erinevas vanuses meriforelli noorkala.
Asustusmaterjali kasvatamiseks on kasutatud nii loodusest püütud kui ka omakasvatatud
sugukalu.
Loodusest püüdsid meriforelli sugukalu kutselised kalurid ühiskondlikus korras, kes sellega
soovisid oma panuse anda meriforelli varude täiendamisse. Sugukalu püüti Selja, Pudisoo ja
Mustoja jõgede suudmealadelt. Kokku saadi 1998 kuni 2006 ja 2010. aastal marja 73
emaskalalt, 253210 marjatera ehk 28,45 liitrit marja. Loodusest püütud emaskalade keskmine
tööviljakus oli 3470 marjatera ühe emaskala kohta. Keskmiselt oli 9040 marjatera ühes liitris.
Erinevatest jõgedest pärit sugukalade viljakuses erinevusi ei ilmnenud.
2002. aastal alustati meriforelli sugukarja loomist Kunda jõest püütud tähnikute
kasvatamisega. 2005. aastal jäeti Pudisoo ja Mustoja jõgedest püütud sugukalade marjast koorunud kaheaastaseid noorkalu sugukarja loomiseks. Marja hakati saama omakasvatatud
sugukaladelt 2005. aastal. Kokku on aastatel 2005 kuni 2011 saadud nendelt 665700 tera ehk
74,3 liitrit marja. Kasvatatud emaskalade tööviljakus oli 1750 marjatera ühe emaskala kohta.
Keskmiselt oli 9500 marjatera ühes liitris. Kunda jõe päritolu sugukalade viljakus oli suurem
kui Pudisoo-Mustoja jõgede koondsugukarja kalade oma.
Kasvanduses kasvatatud sugukalade keskmine tööviljakus oli loodusest püütud sugukalade
keskmisest tööviljakusest ligikaudu kaks korda väiksem. Loodusest saadud ja omakasvatatud
emaskaladelt saadud marja puhul suurt erinevust marjaterade suuruses, mida väljendab terade
arv ühes liitris, ei täheldatud.
Meriforelli kudemine algab Eesti jõgedes vee temperatuuril 4-6°C. Sellisele tasemele jõuab
veetemperatuur enamasti oktoobri teises pooles. Meriforelli jõkketõus algab aga kuu-poolteist
varem ja nagu nähtub loodusest saadud sugukalade püügiandmetest, võib kesta novembrikuu
lõpuni. Meriforelli ja lõhe püük jõgedes on keelatud kas aastaringselt või 1. septembrist 30.
novembrini, kuid erilubadega on see aga lubatud Selja, Valge-, Purtse, Pirita, Vääna, Jägala
ja Narva jões ka kudeajal, välja arvatud ajavahemik 15. oktoobrist kuni 15. novembrini.
Et kalad saaksid rahulikult kudeda, peaks kudeaegne püük kõigis meriforellijõgedes olema
keelatud pikemal perioodil kui praegu.
Sea trout is listed under the vulnerable species category in the Red Data Book of Estonia and needs to be protected. The main reasons for bad conditions of the populations of sea trout are sensitivity of juveniles to the growth conditions, migration obstacles, contamination of reservoirs, overfishing. In Estonia there are Põlula Fish Rearing Centre and Õngu Hatchery that engage in recovery of the sea trout juveniles. The tasks of Põlula Fish Rearing Centre are to grow juveniles of cold water valuable fish species for the purpose of recovering population areas and creating fishing opportunities, collection and preservation of genetical material of endangered salmonids’ populations and activities for support base for scientific research in the field of fish rearing and traineeship for students. This thesis draws conclusions on fish rearing and stocking of sea trout juveniles. Sea trout stocking was started in Põlula in 2001. During 2001-2011 in total it has reared and stocked 310886 summerlings, 82496 one year old fish, 50619 two summer old fish and 63538 two year old fish specimens. The average fecundity of the mature fish reared in a hatchery is 1750 eggs whereas for the mature fish captured from nature it is 3470 eggs. Based on this data it can be concluded that the average fecundity of the mature fish captured from nature is approximately two times bigger than for fish reared in a hatchery. The spawning of the sea trout in Estonian rivers starts at water temperature 4-6°C. Usually the water temperature falls to that level in second half of October. The upriver migration of the seat trout starts a month or even a month and a half earlier. In order for the fish to spawn successfully the spawning time fishing in all sea trout rivers should be forbidden for a longer period than at the moment. Usually the fishing of sea trout and salmon in rivers is forbidden from 1st September to 31st October and with special permits it is allowed in Selja, Valgejõe, Purtse, Pirita, Vääna, Jägala and Narva rivers during spawningtime, except from 15th October to 15th November. The aim of this research was to investigate the contribution of Põlula Fish Rearing Centre to the recruitment of stock. I selected this theme because sea trout has not been studied before and the amount of collected data was enough for analysing and summarising. One of the suggestions for improving the situation is to use more of the sea trout mature fish caught from the nature because the average fecundity of these is significantly bigger than for the mature fish reared in a hatchery. It would also be important to extend the ban of fishing sea trout in rivers because the upriver migration of spawning fish starts before 15th October and dependent on the year the spawning can take place after 15th November.
Sea trout is listed under the vulnerable species category in the Red Data Book of Estonia and needs to be protected. The main reasons for bad conditions of the populations of sea trout are sensitivity of juveniles to the growth conditions, migration obstacles, contamination of reservoirs, overfishing. In Estonia there are Põlula Fish Rearing Centre and Õngu Hatchery that engage in recovery of the sea trout juveniles. The tasks of Põlula Fish Rearing Centre are to grow juveniles of cold water valuable fish species for the purpose of recovering population areas and creating fishing opportunities, collection and preservation of genetical material of endangered salmonids’ populations and activities for support base for scientific research in the field of fish rearing and traineeship for students. This thesis draws conclusions on fish rearing and stocking of sea trout juveniles. Sea trout stocking was started in Põlula in 2001. During 2001-2011 in total it has reared and stocked 310886 summerlings, 82496 one year old fish, 50619 two summer old fish and 63538 two year old fish specimens. The average fecundity of the mature fish reared in a hatchery is 1750 eggs whereas for the mature fish captured from nature it is 3470 eggs. Based on this data it can be concluded that the average fecundity of the mature fish captured from nature is approximately two times bigger than for fish reared in a hatchery. The spawning of the sea trout in Estonian rivers starts at water temperature 4-6°C. Usually the water temperature falls to that level in second half of October. The upriver migration of the seat trout starts a month or even a month and a half earlier. In order for the fish to spawn successfully the spawning time fishing in all sea trout rivers should be forbidden for a longer period than at the moment. Usually the fishing of sea trout and salmon in rivers is forbidden from 1st September to 31st October and with special permits it is allowed in Selja, Valgejõe, Purtse, Pirita, Vääna, Jägala and Narva rivers during spawningtime, except from 15th October to 15th November. The aim of this research was to investigate the contribution of Põlula Fish Rearing Centre to the recruitment of stock. I selected this theme because sea trout has not been studied before and the amount of collected data was enough for analysing and summarising. One of the suggestions for improving the situation is to use more of the sea trout mature fish caught from the nature because the average fecundity of these is significantly bigger than for the mature fish reared in a hatchery. It would also be important to extend the ban of fishing sea trout in rivers because the upriver migration of spawning fish starts before 15th October and dependent on the year the spawning can take place after 15th November.
Kirjeldus
Märksõnad
meriforelli (Salmo trutta trutta L.), Põlula kalakasvatus, varude täiendamine, asustamine, bakalaureusetööd