A parasitic copepod- similar to or possibly Salmincola.
Observation: This is the first time its ever been seen and reported.
Alaska Department of Fish and Game Consult: Ted Meyers writes, "This is a parasitic copepod- similar to or possibly Salmincola. See link to the ADF&G field guide to parasitic copepods." Fish Pathology Laboratory (ADF&G - Commercial Fisheries Division).
LEO says: The ADF&G field guide states, "There are no human health concerns associated with Salmincola."
Resources:
Alaska Department of Fish & Game – "In Alaska, eulachon are seasonally abundant in several drainages from Southeast Alaska, west to the Copper River Delta and westward out to the beaches of Nome in the Bering Sea. Watersheds with eulachon migrations include the Unuk (Eulachon), Stikine, Taku, Mendenhall, Lace, and Chilkat rivers in Southeast Alaska; the Situk and Alsek near Yakutat; the Copper River Delta area near Cordova; and the Kenai, Susitna, and 20-Mile rivers in Cook Inlet."
Euachon — Wildlife Notebook Series (PDF 50 kB)
NOAA Fisheries – "Eulachon, Thaleichthys pacificus (commonly called smelt, candlefish, or hooligan) are a small, anadromous fish from the eastern Pacific Ocean. Eulachon abundance exhibits considerable year-to-year variability. However, nearly all spawning runs from California to southeastern Alaska have declined in the past 20 years, especially since the mid 1990s." Source: NOAA Fisheries, Protected Resources, Species
Observations From Members 