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Scottish Marine and Freshwater Science Reports

Formal report series, containing results of research and monitoring carried out by Marine Scotland Science

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Ranching to the rod: an evaluation of adult returns from hatchery-reared Atlantic salmon smolts released in Scottish rivers

Scottish Marine and Freshwater Science Vol 6 No 5

The introduction of hatchery-reared Atlantic salmon smolts to rivers in support of local salmon fisheries (termed ranching) is a controversial subject with little information available to fishery managers on the value of the method in a Scottish context. Here we present recapture data from monitored smolt releases on four Scottish rivers and compare return rates of hatchery and wild-reared salmon smolts originating from a common stock on two of these rivers. Rod recapture rates from stocked hatchery smolts ranged from 0-0.23%. In comparative tests return rates for wild-reared fish were on average ten times greater than those for stocked fish (range 6 to 13-fold where at least one reared fish returned). Given the relatively poor returns and associated production costs any benefit to fisheries of stocking with hatchery-reared smolts is unlikely to be sustainable in the Scottish context. Furthermore, risks of adverse genetic effects should be considered.

doi: 
10.7489/1610-1
Citation: 
Stewart, D.C., McKelvey, S., Armstrong, J.D. (2015) Ranching to the rod: an evaluation of adult returns from hatchery-reared Atlantic salmon smolts released in Scottish rivers. Scottish Marine and Freshwater Science Vol 6 No 5. Edinburgh: Scottish Government, 13pp.
FieldValue
Publisher
Modified
2020-01-07
Release Date
2015-05-15
Identifier
000bdf73-8629-4941-a9d7-352107f4e8d0
Spatial / Geographical Coverage Location
Scotland
License
UK Open Government Licence (OGL)
Author
Stewart, D.C.
Data Dictionary

To investigate the effectiveness of smolt ranching as a tool to enhance local salmon fisheries, we examine first, the range of recapture rates from monitored smolt releases in Scottish rivers and second, we compare returns from hatchery and wild-reared smolts originating from the same stocks released concurrently at the same river sites. We then consider a range of practical issues associated with operating a smolt ranching scheme on a Scottish river, both for conservation and fishery enhancement purposes, and then, using best available information, assess the likely financial implications.

Contact Name
Marine Scotland Science
Contact Email
Public Access Level
Public