A comparison of tagging methodology for North Pacific giant octopus Enteroctopus dofleini

► We compared two different external tags (Peterson discs and visible implant elastomer) in order to assess their effectiveness for use on octopuses. ► Peterson disc tags can irritate surrounding tissue causing skin necrosis. ► Visible implant elastomer tags were not observed to cause skin necrosis. ► Visible implant elastomer tags were retained by all recaptures. New opportunities for the export of food grade octopus have furthered interest in developing an actively managed directed fishery for North Pacific giant octopus Enteroctopus dofleini in Alaska state waters. Trawl, long-line, and pot fisheries already harvest over 230 metric tons of octopus as bycatch annually. Managed under the authority of commissioner's permits, applications for directed harvest in most management regions have historically been rejected due to the lack of information on stock status. Our limited knowledge of octopus movement, age structure, and demography hamper the ability to successfully manage this potential fishery. Chief among these obstacles is the lack of abundance estimates on which to base harvest guidelines. While catch-per-unit-effort estimates can be made from bycatch data and used as a proxy of abundance, these estimates can often be inaccurate. Mark-recapture estimates can be more accurate, but can also be expensive and require an effective means of marking individuals. We compared two different tags in order to assess their effectiveness for use on octopuses. We tagged 97 octopuses with modified Peterson discs and visible implant elastomer tags in Kachemak Bay, Alaska. Three tagged octopuses were recaptured, making a statistically sound tag comparison difficult. Our data suggest that visible implant elastomer tags will be a more effective means of marking octopuses.