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Freshwater and coastal migration patterns in the silver-stage eel Anguilla anguilla

Barry, J.; Newton, M.; Dodd, J. A.; Lucas, M. C.; Boylan, P.; Adams, C. E.

Authors

J. Barry

M. Newton

M. C. Lucas

P. Boylan

C. E. Adams



Abstract

The unimpeded downstream movement patterns and migration success of small female and male Anguilla anguilla through a catchment in north‐west Europe were studied using an acoustic hydrophone array along the River Finn and into the Foyle Estuary in Ireland. Twenty silver‐stage A. anguilla (total length, LT, range: 332–520 mm) were trapped 152 km upstream from a coastal marine sea‐lough outlet and internally tagged with acoustic transmitters of which 19 initiated downstream migration. Migration speed was highly influenced by river flow within the freshwater (FW) compartment. Anguilla anguilla activity patterns were correlated with environmental influences; light, tidal direction and lunar phase all influenced the initiation of migration of tagged individuals. Migration speed varied significantly between upstream and lower river compartments. Individuals migrated at a slower speed in transitional water and sea‐lough compartments compared with the FW compartment. While 88·5% survival was recorded during migration through the upper 121 km of the river and estuary, only 26% of A. anguilla which initiated downstream migration were detected at the outermost end of the acoustic array. Telemetry equipment functioned efficiently, including in the sea‐lough, so this suggests high levels of mortality during sea‐lough migration, or less likely, long‐term sea‐lough residence by silver A. anguilla emigrants. This has important implications for eel management plans.

Citation

Barry, J., Newton, M., Dodd, J. A., Lucas, M. C., Boylan, P., & Adams, C. E. (2016). Freshwater and coastal migration patterns in the silver-stage eel Anguilla anguilla. Journal of Fish Biology, 88(2), 676-689. https://doi.org/10.1111/jfb.12865

Journal Article Type Article
Acceptance Date Nov 6, 2015
Online Publication Date Dec 28, 2015
Publication Date Feb 17, 2016
Deposit Date Oct 17, 2019
Journal Journal of Fish Biology
Print ISSN 0022-1112
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 88
Issue 2
Pages 676-689
DOI https://doi.org/10.1111/jfb.12865
Keywords Anguillidae, migration triggers, sea‐lough, survival, telemetry
Public URL http://researchrepository.napier.ac.uk/Output/1802968