How Close Is Too Close?

The largest aggregations of harbor seals in the world occur on floating ice calved from tidewater glaciers in Alaska, USA. Some populations are inexplicably declining. Seals increasingly flush from the ice when cruise ships approach closer than 400 m, 90% flushing at 91 m (100 yards) – the current guideline for minimum approach distance. The U.S. MMPA prohibits the “taking” of marine mammals, which is defined to include disturbance, but currently there are no binding or enforceable limits on approaches to seals in Alaska State waters. Despite the short-term nature of individual disturbance events, the likelihood of long-term impacts points to the need for management action.