BIOLOGICAL OPINION On the Effects of the Akutan Airport Project on Steller’s Eiders (Polysticta stelleri) and Northern Sea Otter (Enhydra lutris kenyoni) Table Of Contents: DESCRIPTION OF PROPOSED ACTION................................................................................ 4 STATUS OF THE SPECIES - Steller’s eider (Polysticta stelleri).............................................. 7 Species Description........................................................................................................................................................7 Life History ....................................................................................................................................................................7 Longevity....................................................................................................................................................................7 Energetics...................................................................................................................................................................7 Age to Maturity ..........................................................................................................................................................7 Reproductive Strategy................................................................................................................................................8 Recruitment................................................................................................................................................................8 Seasonal Distribution Patterns..................................................................................................................................8 Site Fidelity ..............................................................................................................................................................12 Population Structure ...............................................................................................................................................13 Food Habits..............................................................................................................................................................13 Predators ..................................................................................................................................................................13 Population Dynamics ..................................................................................................................................................14 Population Size ........................................................................................................................................................14 Population Variability .............................................................................................................................................18 Population Stability .................................................................................................................................................18 Status and Distribution...............................................................................................................................................18 Reasons for Listing..................................................................................................................................................18 Range-wide Trend....................................................................................................................................................19 Threats Not Assessed At the Time Of Listing .........................................................................................................20 STATUS OF THE SPECIES - Northern Sea Otter (Enhydra lutris kenyoni) ........................ 27 Species Description......................................................................................................................................................27 Life History ..................................................................................................................................................................27 Longevity..................................................................................................................................................................27 Energetics.................................................................................................................................................................27 Age to Maturity ........................................................................................................................................................27 Reproductive Strategy..............................................................................................................................................27 Recruitment..............................................................................................................................................................28 Distribution ..............................................................................................................................................................28 Movement Patterns ..................................................................................................................................................29 Site Fidelity ..............................................................................................................................................................29 Population Structure ...............................................................................................................................................29 Habitat......................................................................................................................................................................30 Food Habits..............................................................................................................................................................30 Predators ..................................................................................................................................................................30 1 Population Dynamics ..................................................................................................................................................31 Population Size ........................................................................................................................................................31 Population Variability .............................................................................................................................................34 Population Stability .................................................................................................................................................35 Status and Distribution...............................................................................................................................................35 Reasons for Listing..................................................................................................................................................35 Range-Wide Trend...................................................................................................................................................38 ENVIRONMENTAL BASELINE .............................................................................................. 38 Assumptions Used in Analysis of Past, Present and Future Effects........................................................................38 Proportion of Wintering Steller’s Eiders from Listed Population .........................................................................38 Temporal Distribution - Northern Sea Otters.........................................................................................................39 Life of the Project ....................................................................................................................................................39 Determination of Action Area ....................................................................................................................................39 Status of the Species within the Action Area.............................................................................................................39 Steller’s eiders.........................................................................................................................................................39 Northern sea otter...................................................................................................................................................40 Factors Affecting Species’ Environment in the Action Area...................................................................................41 Seafood Processor Organic Waste ..........................................................................................................................41 Petroleum Spills.......................................................................................................................................................42 Collisions with Vessels and Harbor-Related Structures.........................................................................................42 Incidental Take Of Steller’s Eiders Permitted For Other Federal Actions ...........................................................43