From Natural History of Southeast Alaska
Shipworm (Bankia setacea) which digs large burrows, the gribble digs very small burrows (usually only about a millimeter in diameter), and survives quite well on the beach. Although it's essentially a longish roly-poly, the gribble looks somewhat like a worm at the macroscopic level. When observed with a dissecting microscope or good hand lens, though, it's worth looking for a similar species, called Limnoria tripunctata. It is not clear to the writer of this article whether this species is present in Alaska, but it can be categorically identified by the presence of three small rear-facing tubercles on the pleotelson.
The larger isopod that isn't a wood borer but is commonly seen on driftwood, especially in estuaries, is Oregon pillbug (Gnorimosphaeroma oregonensis). This one is clearly roly poly-like, and dark in color.
- WoRMS Page for Limnoria lignorum
- Search Arctos Database for Limnoria lignorum (Southeast only)
- Search Arctos Database for Limnoria lignorum (entire database)
- Encyclopedia of Life search for Limnoria lignorum
- iNaturalist Observations for Limnoria lignorum in Southeast Alaska