Some of the risks described in the next two sections may be especially acute as people and animals habituate to the presence of commercial ships, even as other risks increase with the volume of traffic over time. The Bering Strait region is ecologically rich with high species diversity

due in part to the overall productivity of the area, in part because it is a corridor between the Bering and Chukchi seas, and in part because it sits on the Arctic-subarctic ecotone (boundary between ecosystems) [4], [6], [20], [21], [22] and [23]. Vessels navigating the Bering Strait region pose numerous environmental threats including collisions with marine Bcl-2 inhibitor mammals (ship strikes), disturbance of seabirds and marine mammals, increased noise, and contamination of the marine environment (e.g., discharges, air pollution, waste, or ballast water that contains invasive species). Other threats include the potential for an accident such as grounding or sinking of a vessel, which would endanger

LY294002 mw the crew and rescue personnel in addition to threatening an environmental disaster. In light of the lack of capacity to respond due to remoteness and challenging conditions, most worrisome is the prospect of an oil spill, either from a tanker or of fuel oil from any vessel transiting the area. Direct collisions between vessels and marine mammals can result in mortality through massive trauma. Worldwide records of ship strikes on whales show that all large whales are at risk [24] and [25], with bowhead whales most likely to be at risk in the Bering Strait region. Bowheads seasonally congregate in the Bering Sea and the entire population of the Bering/Chukchi stock transits the Bering Strait twice a year. The period of greatest concern is in the fall (October through November) as bowheads move

south along the Chukotka coast into the Strait at a time when vessel traffic remains high [26]. During spring, whales, walrus, and seals migrate north when sea ice is still present, so the risk of ship strikes is reduced due to lower levels of vessel traffic. Icebreakers, however, have selleck compound the potential to disturb animals and habitat during spring migration. Ice-dependent seals are potentially at risk of displacement during spring and early summer (April through June) when they use ice for pupping and for molting. Sound is vital to survival of marine mammals as they use it to detect their environment and communicate with one another [27] and [28]. Persistent or increasing noise disturbance could alter health, behavioral and migratory patterns [29]. Responses to vessels (e.g., disturbance) have been documented in a wide variety of marine mammal species and primarily include avoidance behavior and increased stress.