Common Murre

(Uria aalge)

The common murre, also known as the common guillemot, is an abundant seabird found throughout much of the northern Atlantic and Pacific Oceans.  Common murres breed in large colonies of thousands to hundreds of thousands (1) and individuals often return to their natal colonies year after year (2).  There are two recognized subspecies in the Pacific and five in the Atlantic (2), and the global population is estimated at 18 million birds (3).

Common murres are one of the species most affected by gillnet bycatch worldwide (4) and frequently interact with coastal drift and set gillnets for salmon and cod (4-6).  Although it is considered a species of Least Concern by the International Union for the Conservation of Nature (3), high levels of anthropogenic mortality can to pose a localized threat.  In the Baltic Sea, an estimated nine thousand murres are killed annually in salmon gillnets (6).  In the early 1980s an estimated 22,000 murres were killed annually in nets off coastal Newfoundland (7), though fishing effort has declined since the collapse and closure of the Canadian groundfish fishery (5). High levels of anthropogenic mortality can also have enduring consequences.  Common murres were once found as far south as the Iberian Peninsula, until the population crashed due to extremely high adult mortality in the 1960s and 1970s, caused in part by the introduction of synthetic fiber gillnets (8).

Several behaviors of common murres make them particularly vulnerable to gillnet bycatch.  Diving birds in general are susceptible to gillnet bycatch (4), and pursuit divers like common murres, capable of diving to 100m (9) have even greater potential to interact with nets (5).  Common murres also forage on the same large aggregations of baitfish, such as sprat, capelin, herring and anchovy (5,6,10,11), which support commerical cod and salmon fisheries.  Consequently, bycatch rates peak seasonally and spatially when fishing effort coincides with high numbers of foraging birds (5,7).  Bycatch rates of common murres also tend to be higher near breeding colonies (7).  Other sources of anthropogenic mortality can include oil pollution and direct harvest in parts of Canada and Greenland (12,13).

The mitigation of gillnet bycatch involves a combination of regulatory solutions and gear modifications.  The experimental use of visible mesh panels and acoustic alerts or pingers (similar to those used to deter marine mammals) were shown to reduce murre bycatch by almost half in the Puget Sound salmon driftnet fishery (4).  Fishing restrictions can also be used to reduce fishing effort when and where interactions between murre and fishing gear are most likely to occur.  These could include additional protection for the biological hotspots created by seasonal aggregations of forage fish (5).  In additional, a multispecies approach, which considers relative abundances of target and non-target species, could be used to determine optimal timing for limited fishing seasons (4).

References and additional resources:

1.  Morris-Pocock, J.A., S.A. Taylor, T.P. Birt, J.F. Piatt, K.I. Warheit, and V.L. Friesen. 2008. Population genetic structure in Atlantic and Pacific Ocean common murries (Uria aalge): natural replicate tests of post-Pleistocene evolution. Molecular Ecology 17:4859-4873

2.  Manuwal D.A., H.R. Carter, T.S. Zimmerman, and D.L. Orthmeyer, Editors. 2001. Biology and conservation of the common murre in California, Oregon, Washington, and British Columbia. Volume 1: Natural history and population trends. U.S. Geological Survey, Biological Resources Division, Information and Technology Report USGS/BRD/ITR-2000-2012, Washington, D.C. 132 pp.

3.  BirdLife International 2008. Uria aalge. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded 10 January 2009.

4.  Melvin, E.F., J.K. Parrish, and L.L. Conquest. 1999. Novel tools to reduce seabird bycatch in coastal gillnet fisheries. Conservation Biology 13(6): 1386-1397

5.  Davoren, G.K. 2007. Effects of gill-net fishing on marine birds in a biological hotspot in the northwest Atlantic. Conservation Biology 21(4): 1032-1045

6.  Österblom, H., M. Casini, O. Olsson, and A. Bigmert. 2002 . Fish, seabirds and trophic cascades in the Baltic Sea. Marine Ecology Progress Series 323: 233-238

7.  Piatt, J.F. and D.N. Nettleship. 1987. Incidental catch of marine birds and mammals in fishing nets off Newfoundland, Canada. Marine Pollution Bulletin 18 (6B):344-349

8.  Munilla, I., C. Díez, and A. Velando. 2007. Are edge bird populations doomed to extinction? A retrospective analysis of the common guillemot collapse in Iberia. Biological Conservation 137: 359-371

9.  Piatt, J.F. and D.N. Nettleship. 1985. Diving depths of four alcids. The Auk: 102 (2): 293-297

10. Wilhelm, S.I., G.J. Robertson, P.A. Taylor, S.G. Gilliland, and D.L. Pinsent. 2003. Stomach contents of breeding common murres caught in gillnets off Newfoundland. Waterbirds 26(3): 376-378

11. Lance, M.M. and C.W. Thompson. 2005. Overlap in diets and foraging of common murres (Uria aalge) and rhinocerous auklets (Cerorhinca monocerata) after the breeding season. The Auk: 122(3): 887-901

12. Wilhelm, S.I., S.C. Gilliland, G.J. Robertson, P.C. Ryan, and R.D. Elliot. 2008. Development and validation of a wing key to improve harvest management of alcids in the Northwest Atlantic. Journal of Wildlife Management 72(4): 1026-1034

13. Robertson, G.J., A.E. Storey, S.I. Wilhelm. 2006. Local survival rates of common murres breeding in Witless Bay, Newfoundland. Journal of Wildlife Management 70 (2): 584-587

14. Harris, M.P. and S. Wanless. 2004. Common guillemot. In: Mitchell, PI., Stephen, F.N., Ratcliffe, N., and T.D. Tunn (Eds.), Seabird Populations of Britain and Ireland. T&A.D. Poyser, London, pp. 350-363