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Economics and society


	Fish resources	Exploitation of fish stocks		Fish stocking research		Environment of fish	Baltic Sea Research	Regulated Rivers	Crayfish	Fish atlas

Fish stocking research programme 2006-2012:


»	Current issues in stocking

»	Beneficiaries and impacts of the programme


»	Contents of the research programme
	•	Physiological analyses
	•	Results of the whitefish stockings in the Gulf of Bothnia
	•	Successful stocking
	•	The effect of stocking age on the survival of Saimaa Arctic charr in lakes with different fisheries
	•	Factors contributing to the quality of stocked landlocked salmon juveniles
	•	Biological basis for restoration of the natural life cycle of landlocked salmon

The effect of stocking age on the survival of Saimaa Arctic charr in lakes with different fisheries

Saimaa charr form the only southern charr population in Finland, but is nowadays extremely endangered. There is only one naturally reproducing population and it is also near to die out. A restocking program in earlier charr lakes was started in the 1990s, but definite observations of new spawning populations in these lakes have not been made so far. This project, which is part of the RKTL Fish stocking research program, aims at evaluating and improving the success of the charr restocking programs.

Photo: Irma Kolari

Goals

Saimaa Arctic charr are usually stocked at the age of one or two years in Finland. We studied the possibility to stock eyed eggs or newly hatched larvae along with older juveniles. The use of early life stages would decrease the risk of deficits associated with captive rearing, like relaxed predator avoidance and decreased feeding success in wild. We also try to estimate the effect of fisheries on the stocking result of Saimaa charr. In one stocking lake fisheries are totally forbidden whereas in the other there are multispecies fisheries, typical for Finnish lakes.

Benefits

The results of this study would help to develop the management practices of extremely endangered Saimaa charr. The results could benefit all the parties involved in the management of Saimaa charr, like governmental authorities, water owners and fishermen.

The enhancement and restocking programs of Saimaa charr have relied on the maintenance of a hatchery brood-stock in a state-owned hatchery run by the RKTL. The present brood fish represent however already the second or third hatchery generation, which increases the risk of undesired domestication. Successful restocking of charr in new areas would help us to create a new brood stock from stocked fish that have gone through natural selection. The creation of the new brood stock has been started.

Moreover, the successful creation of new charr populations in Saimaa lake area would help to maintain biodiversity. Saimaa charr are large growing fish and a highly appreciated target in fisheries. The possibility to catch such a fish would increase the attractiveness of the lake area.

Further information

Irma Kolari

Duration

2008 - 2012

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