title: Does size matter? A test of size-specific mortality in Atlantic salmon Salmo salar smolts tagged with acoustic transmitters.
abstract: Mortality rates of wild Atlantic salmon Salmo salar smolts implanted with acoustic transmitters were assessed to determine if mortality was size dependent. The routinely accepted, but widely debated, '2% transmitter mass: body mass' rule in biotelemetry was tested by extending the transmitter burden up to 12·7% of body mass in small [mean fork length (LF ) 138·3 mm, range 115-168 mm] downstream migrating S. salar smolts. Over the short timescale of emigration (range 11·9-44·5 days) through the lower river and estuary, mortality was not related to S. salar size, nor was a relationship found between mortality probability and transmitter mass: body mass or transmitter length: LF ratios. This study provides further evidence that smolt migration studies can deviate from the '2% rule' of thumb, to more appropriate study-specific measures, which enables the use of fishes representative of the body size in natural populations without undue effects.
authors.affiliation: Scottish Centre for Ecology & the Natural Environment, IBAHCM, University of Glasgow, Rowardennan, Glasgow, G63 0AW, U.K.
authors.forename: M
authors.initials: M
authors.lastname: Newton
authors.affiliation: Scottish Centre for Ecology & the Natural Environment, IBAHCM, University of Glasgow, Rowardennan, Glasgow, G63 0AW, U.K.
authors.forename: J
authors.initials: J
authors.lastname: Barry
authors.affiliation: Scottish Centre for Ecology & the Natural Environment, IBAHCM, University of Glasgow, Rowardennan, Glasgow, G63 0AW, U.K.
authors.forename: J A
authors.initials: JA
authors.lastname: Dodd
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, U.K.
authors.forename: M C
authors.initials: MC
authors.lastname: Lucas
authors.affiliation: Loughs Agency, 22 Victoria Road, Derry, Northern Ireland, BT47 2AB, U.K.
authors.forename: P
authors.initials: P
authors.lastname: Boylan
authors.affiliation: Scottish Centre for Ecology & the Natural Environment, IBAHCM, University of Glasgow, Rowardennan, Glasgow, G63 0AW, U.K.
authors.forename: C E
authors.initials: CE
authors.lastname: Adams
mesh_terms: D000162:Acoustics; D025041:Animal Migration; D000818:Animals; D049628:Body Size; D063366:Estuaries; D009026:Mortality; D045483:Rivers; D020317:Salmo salar; D012474:Salmon; D013686:Telemetry / Q000379:methods*
keywords: biotelemetry; migration; tag burden; transmitter effects