He exposes his bias when he damns the world’s shellfish industries. Studies such as “Is Ocean Acidification an Open-Ocean Syndrome? Understanding Anthropomorphic Impacts on Seawater pH” (Duarte et al) address the complexities involved; (natural) “changes in watersheds…yield high-magnitude decadal changes of up to 0.5 units in coastal pH”. This natural variance in pH overlies the .1 unit of decrease in pH attributed to human C02 emissions, a decrease reached over the entirety of the industrial revolution.

The effect of decreased pH and the concurrent decrease in carbonate ions varies greatly between shell building species. Without long term studies of the shellfish in question it is baseless conjecture to attribute entire population declines to anthropogenic C02 emissions.

I also find it counterintuitive that in an area such as SE Alaska, which is subject to the vigorous Japanese Current and huge tidal action, that local C02 absorption by kelp would have any significant impact on local pH levels.

Perhaps a wise way forward would be to initiate a controlled study, starting with a count of shellfish in a controlled area, followed by the culling of the sea otters that enter the study site. At specified intervals the shellfish population could be reassessed. This would be a great time to assess kelp impact on C02 absorption and pH levels as well.