The issue of seal predation came up during the legislative hearing on the State Auditors Office (SAO) performance audit of the WDFW Blackmouth program a few years back. Lots of stats about significant reductions in the contribution rate by hatchery releases driving up the cost of each such fish harvested. Culprit? Seals do eat salmon.

Then came the P.S. Rockfish Recovery plan and hearings. In that draft plan citing limitations on recovery there was a section of food chain factors. In that section seal predation was cited and rated as minimal based upon there being approx 15 thousand seals in Puget Sound (inland waters) consuming 5 million pounds of food (fish) calculated by WDFW based upon cited average seal weight and daily consumption needs per pound of body weight. That 5MM pounds was a bogus number as a quick series of calculator inputs yielded a number of 27MM pounds. And seals DO eat rockfish! I think it was that same Lane study cited by Lucky Louie which described scat studies and yielded a percentage with rockfish DNA. Oh, and the WDFW personnel pushing that program, having been advised of their significant error, continued to utilize it throughout the rest of their public hearings.

The data I researched indicated that there were only a couple of hundred seals in P.S. in the early 70s as the result of a Dept. of Fisheries bounty program. Between that program going away and the MMPA the seal population grew exponentially to a number probably around 17M now.

So, bottom line, if one were to plot the decrease in blackmouth contribution rates and rockfish numbers over that same period you would see a clear inverse relationship. And seals do eat salmon as well as rockfish and if the total poundage for 17M seals is approx 30MM of food it doesn't take a very big percentage to equal a lot of blackmouth, rockfish and/or (gasp) steelhead.

The 30K number recently thrown around was for the Salish Sea to include inland Canadian waters and in WA the coastal seal population is counted separately from P.S. numbers.