Friday Harbor Labs Tide Bites

Posted January 19, 2021 at 5:00 am by

Sea Otter Disturbance

By Dr. Tiff Stephens

In the sum­mer of 2017, I trav­eled to Fri­day Har­bor Labs for one of my usu­al short vis­its of recon­nect­ing with res­i­dent sci­en­tists and div­ing into the waters to see how the sea­weed com­mu­ni­ties have changed at favored sites (Reuben Tarte, Cat­tle Point, Dead­man Bay).

I also trav­eled there to catch a ride north: I jumped onto a 42’ Nordic Tug and steamed direct­ly from FHL’s break­wa­ter to Prince of Wales Island (POW, South­east Alas­ka) via the Inside Pas­sage, with the ulti­mate goal of relo­cat­ing for a post­doc­tor­al fel­low­ship that was to inves­ti­gate the role of sea otters in eel­grass habi­tat (UAF, Eck­ert Lab).

It must be said: sea otters are unforgiving.

Their tenac­i­ty, in fact, is not quite appre­ci­at­ed until one has the oppor­tu­ni­ty to observe their dai­ly for­ag­ing habits. As we round­ed the north­ern point of POW Island into a calm, fog-enshroud­ed Shakan Bay, we noticed dozens of sea otters sim­mer­ing to the sur­face around us, each return­ing with a prize to dis­mem­ber and con­sume: clam, clam, clam, sea cucum­ber, clam, clam, bas­ket star…BASKET STAR?

Like I said, sea otters are unfor­giv­ing. Although their role as a preda­tor is can­on­ized in texts that describe the cas­cad­ing effects of their con­sump­tion of urchin and abalone (Estes et al. 1978, Dug­gins 1980), this should not sug­gest that their activ­i­ty is lim­it­ed to rocky areas.

Sea otters are gen­er­al­ist preda­tors that con­sume over 200 species across a spec­trum of rocky and soft sub­strates. Diet analy­sis sug­gests that but­ter clams are their pre­ferred prey in South­east Alas­ka (La Roche 2020). What wasn’t appar­ent from the sur­face as we cruised through the cor­ri­dor of sea otter car­nage in Shakan Bay was what effect the for­ag­ing activ­i­ty had on the soft seafloor below, which was what I was to lat­er inves­ti­gate in eel­grass habitat.

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Categories: Animals, Nature, Science

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