Another thing that is not being looked at here--at least not enough--is the possibility of infection by Toxoplasma gondii oocysts.  The oocysts survive and remain infectious for up to 4.5 years--even in sea water.  They're contaminating nearshore marine habitat.  Filter-feeding fish like Pacific sardines and anchovies are taking them up and the oocysts are embedding in their tissues.  So are filter-feeding bivalves (enjoy those raw oysters, folks!).  The fish may be spreading them into the open ocean.  And the parasite is being ingested by marine mammals and killing them by the thousands from--at least--British Columbia to New Zealand and beyond.  They're definitely already in the Alaskan terrestrial environment--a pregnant woman and her unborn child were infected after she ate a moose which had ingested T. gondii oocysts two years ago.  If they're on land, runoff will carry them to the sea.