effects on the nesting success of common murres18

. The

unsustainable harvesting of all seabirds, including alcids, is of concern in some Arctic countries (e.g., Greenland19

).

Finally, introduced predators such as dogs, cats, mink, and rats, which have devastated seabird populations in the past in more southerly regions, poses a threat to burrow-nesting alcids, such as the tufted puffin, Fratercula cirrhata15,20

eradications in Canada, Alaska and elsewhere have substantially increased safe nesting habitat for seabirds5

I .

. Predator , although

introduction of predators may increase as growing human developments expand north15

deposition. Declines in ice may affect the ability of birds to find energy-rich food at dependable locations by shifting the spatial distribution of underlying food webs15

. Climate change may

also affect the temporal distribution of prey species, and cause a mismatch at the time of breeding between food availability and nutritional requirements16,17

. II

Alcids, like many Arctic wildlife species, are exposed to persistent organic pollutants (POPs)8,9

. Because they are located near the

top of the food chain, their contaminant levels are high relative to fish and plankton, although mostly below known effect levels8

.

With Arctic nations having some of the most active fisheries in the world, fishing operations also pose a threat to alcids through by-catch mortality10

reduce the food for seabirds12,13

and unsustainable fishing practices, which . Historically, hundreds of

thousands of murres have been taken in net fisheries from Greenland, Norway, and Russia. Today, seabird by-catch is thought to be declining to negligible levels although this is not monitored routinely on shipping vessels in Arctic nations other than some US fisheries10

. Overexploitation of fish stocks

has also had a dramatic impact on some alcid populations, including on common murres feeding on Barents Sea capelin12 and Atlantic puffins feeding on Barents Sea herring13

.

Human disturbance of alcids and other seabirds at breeding colonies is thought to pose a threat, and can have negative

60 PROTECTING ARCTIC BIODIVERSITY ,

Marine pollution, especially oil, is a significant threat. Alcids are particularly sensitive to even small oil spills because of their concentrated aggregations5,21

. There is also concern over

the impacts of cruise ship tourism on Arctic seabird colonies, given its rapid growth14

groundings and other accidents, which may result in oil spills and other consequences14

.

Management challenges and opportunities Alcids are subject to highly varied national and local management regimes across the Arctic, and a number of international legal agreements, conventions, and instruments are in place for the management of some species.

. Across Arctic countries it is recognized that more information on seabird population trends and harvests is needed as a basis for sustainable harvest management6

.

A variety of management regimes exist to control the harvesting of seabirds. In the USA and Canada, for example, protection for migratory birds exists under national legislation that implements the North American Migratory Bird Convention of 1916 in each country. The only seabirds that can be harvested legally in either country are the common and thick-billed murres in a hunt open only to residents of Newfoundland and Labrador. Russia, despite having signed a number of international and bilateral agreements, has no adequate legal framework in place for the management and protection of marine ecosystems and its associated species within the Arctic regions6

. Greater ship traffic increases the risk of