From what I gather:

Poor circulation (long, narrow fjord get little in the way of freash, outside water).

fertilizer and septic leaks cause nutrients to rise and creating algae blooms.

Thousands of dead, rotting, chums left by the indians on the shore that take up oxygen while decomposing and add lots of nutrients that are supposed to go mostly to the rivers/creeks, not the saltwater thus, also creating algae blooms. (supprising that I haven't heard the media/state mention this :rolleyes: ).