Stocking success of newly hatched pike evaluated by radioactive strontium ( 85 Sr) marking

• Published in: Journal of Fish Biology
• Main Authors: Sutela, T., Korhonen, P., Nyberg, K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2004
• Subjects: Lokka; Lokka reservoir
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.2004.00329.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.2004.00329.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.2004.00329.x

The stocking of newly hatched pike Esox lucius labelled with radioactive strontium ( 85 Sr) and later electrofishing of the same area was found to be a workable tool in assessing the success of pike stockings. 85 Sr‐labelled individuals constituted 96% of the 0+year pike catch from late summer electrofishing in the stocked littoral areas of the heavily regulated Lokka Reservoir. The density of 0+year pike reached 2·1 individuals 100 m −2 in the stocked areas in comparison to 0·3 individuals 100 m −2 in the reference areas. In the three other stocked lakes the proportion of labelled pike in the catch ranged from 0 to 42% in late summer. The results suggest that pike stockings are profitable in filling empty or nearly empty 0+year pike habitats of regulated lakes or other waterbodies, where the natural reproduction of pike has declined due to human activities.