Local Survival Rates of Common Murres Breeding in Witless Bay, Newfoundland

Robertson, Gregory J.; Storey, Anne E.; Wilhelm, Sabina I.

doi:10.2193/0022-541x(2006)70[584:lsrocm]2.0.co;2

Cited by 10 publications

(9 citation statements)

References 24 publications

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“…The general picture that emerged was of whiskered auklets having survival rates very similar to least and crested auklets, but lower than those of larger alcids such as murres ( Uria spp., e.g. Sandvik et al 2005, Robertson et al. in press), and we found evidence for a direct negative effect of climate rather than an indirect effect operating through ocean productivity.…”

Section: Discussionsupporting

confidence: 51%

Covariation among demographic and climate parameters in whiskered auklets Aethia pygmaea

Jones

Hunter²,

Robertson³

et al. 2007

Journal of Avian Biology

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Annual survival rate and other demographic parameters of whiskered auklets Aethia pygmaea , a small planktivorous seabird, were measured at Buldir Island Alaska during 1992 Á2003 to provide comparative information for auk life history studies and to test for links among climate, age, productivity and survival. Using two 9 m mistnets, we captured and recaptured 384 adult and 193 sub-adult (one year old, a known-age component of our sample) birds as they arrived at the colony after dark during May and June (1,730 capture events). The best fitting model indicated a lower initial survival rate over the first year following marking (0.70890.036 SE), and subsequent survival (mean 0.83590.029) covarying with the Aleutian Low Pressure climate Index, with higher auklet survival in years with weak low pressure over the Aleutian Islands. Annual survival rate varied from 0.72690.127 in 1998 Á99 to 0.99490.077 in 1994 Á95, rates similar to those previously reported for least A. pusilla and crested auklets A. cristatella . A model based only on recaptures of known-age birds indicated a lower local survival estimate over the first year following marking (age one to two years), with no other age-effects on survival. Breeding propensity by age inferred from recaptures of birds with fully-developed brood patches that were originally marked as sub-adults (one year olds) indicated 53% breeding at age two, 94% breeding at age 3, 97% breeding at age 4 and 100% breeding thereafter. The sex ratio of the sampled birds was significantly male biased (60/40), likely due to differences in behaviour between males and females during the incubation stage. Taken together, our data indicate that whiskered auklet survival and productivity covaried with continuous variation in large-scale climatic conditions, the mechanism being either negative effects of stormy North Pacific weather or indirect effects on food supplies.

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Section: Discussionsupporting

confidence: 51%

Covariation among demographic and climate parameters in whiskered auklets Aethia pygmaea

Jones

Hunter²,

Robertson³

et al. 2007

Journal of Avian Biology

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“…While our data indicate that Funk Island adults (and females, in particular) may be vulnerable to fall (north coast) and late season (January-March; north, east and south coast) hunts when inshore (Figs 2 and 3), the relatively coarse resolution of our GLS data do not preclude the possibility that they are distributed sufficiently far from shore as to be beyond the range of hunters. Indeed, the little information available suggests that adult common murres are very rarely taken in the murre hunt (Robertson, Storey & Wilhelm, 2006;G. J. Robertson, Environment Canada, unpubl.…”

Section: Discussionmentioning

confidence: 99%

“…Through provision of colony-and agespecific spatial residency times, information from GLS (and other types of tracking) devices is likely to be an important component of the toolset we use to unravel the relative risks. While the overall pressure on eastern Canadian murre populations from hunting, fisheries bycatch and chronic oil pollution has likely been reduced in recent decades, cumulative annual mortality for common murre remains substantial ($60 000 individuals) and its allocation between ageclasses and colonies is poorly known (Robertson et al, 2006). As oil pollution is a persistent source of increased mortality and decreased fecundity for seabirds worldwide (Ford et al, 1982;Piatt et al, 1990;Votier et al, 2005;Wilhelm et al, 2009;Wolfaardt et al, 2009), filling the local information gap surrounding seabirds and the offshore oil and gas industry has been highlighted as a conservation priority.…”

Section: Discussionmentioning

confidence: 99%

Reducing uncertainty on the Grand Bank: tracking and vessel surveys indicate mortality risks for common murres in the North-West Atlantic

et al. 2011

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Seabirds and other marine animals are at risk from anthropogenic activities that target them directly and those that can harm them incidentally. We integrate yearround tracking and vessel studies to assess risks for a globally important seabird population in the North-West Atlantic. The eastern Canadian Grand Bank has a rich and diverse food web that supports an abundance of apex predators. Major resource extraction industries (hydrocarbon production and fisheries) operate in the area, and, in addition to shipping and hunting, pose risks for marine birds. Understanding the relative risks has been hampered by poor information on bird distribution at sea. Here, we deployed global location sensors (loggers or geolocators) on common murres Uria aalge at Funk Island, the species' largest North American breeding colony. Adults (n = 10) were resident on the Grand Bank and in adjacent pelagic waters year round. Within 10 days of leaving the colony, males dispersed offshore (o501W), south-south-east of Funk Island. Females departed later and spent 10-47 days in coastal waters before moving offshore. All birds were in the vicinity of offshore oil platforms during November and December, but remained outside the area of the coastal Newfoundland and Labrador murre hunt. Three of six tracked females, but only one of four tracked males moved closer to shore during January and February where vulnerability to the hunt may have increased. Vessel-based surveys confirmed the importance of offshore, shelf-edge habitats for murres in winter. Our results highlight the relative risk to wintering murres from different human activities, providing a sound scientific rationale for focusing conservation and management actions. This information is particularly timely given the continued expansion of deep-water drilling in the North-West Atlantic and increasing risk of oil pollution for seabirds attracted to platforms.

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“…Owing to the difficulties of censusing large colonies of seabirds, it is hard to assess whether bycatch mortality has had an impact on population size until there are substantial declines (Chardine 1998). Population trends available for Common Murres at Funk Island suggest that this colony is stable (Chardine et al 2003), whereas other colonies are increasing (Robertson et al 2006). This indicates that the Funk Island colony is either at carrying capacity or that bycatch mortality, combined with other demographic parameters (e.g., Davoren & Montevecchi 2003 a,b ), is high enough to limit population growth.…”

Section: Discussionmentioning

confidence: 99%

Effects of Gill‐Net Fishing on Marine Birds in a Biological Hotspot in the Northwest Atlantic

Davoren

2007

Conservation Biology

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Marine biological hotspots, or areas where high abundances of species overlap in space and time, are ecologically important areas because energy flow through marine food webs, a key ecosystem process, is maximized in these areas. I investigated whether top predators aggregated at persistent spawning sites of a key forage fish species, capelin (Mallotus villosus), on the NE coast of Newfoundland during July and August 2000-2003. By examining the distributional patterns of top predators through ship-based surveys at multiple spatial and temporal scales, I found that the biomasses of birds-dominated by Common Murres (Uria aalge)-and mammals-dominated by whale species-were concentrated along the coast, with a biological hotspot forming near two persistent spawning sites of capelin in all years. The formation of this hotspot was well defined in space and time from middle of July to middle of August, likely coinciding with the spawning chronology of capelin. Within this hotspot, there was a high spatial and temporal overlap of Common Murres and gill nets set to capture Atlantic cod (Gadus morhua). This resulted in breeding murres becoming entangled in gill nets while feeding on spawning capelin. Despite an acknowledged uncertainty of bycatch mortality, estimates for the larger regional-scale area (1936-4973 murres/year; 0.2-0.6% of the breeding population) underestimated mortality relative to estimates within the hotspot (3053-14054 murres/year; 0.4-1.7%). Although fishing effort for Atlantic cod has declined substantially since the groundfish moratorium in 1992, chronic, unnatural, and additive mortality through bycatch continues in coastal Newfoundland. Restricted use of gill nets within this and other biological hotspots during the capelin spawning period appears to be a straightforward application of the "ecological and biologically significant area" management framework in Canada's Oceans Act. This protection would minimize murre bycatch and maintain ecosystem integrity.

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Local Survival Rates of Common Murres Breeding in Witless Bay, Newfoundland

Cited by 10 publications

References 24 publications

Covariation among demographic and climate parameters in whiskered auklets Aethia pygmaea

Covariation among demographic and climate parameters in whiskered auklets Aethia pygmaea

Reducing uncertainty on the Grand Bank: tracking and vessel surveys indicate mortality risks for common murres in the North-West Atlantic

Effects of Gill‐Net Fishing on Marine Birds in a Biological Hotspot in the Northwest Atlantic

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