Answer: Anisakid worm ( including Anisakis spp. or Pseudoterranova decipiens).
To see this worm in its "cooked" state, take a peak at my previous posting HERE
These worms are nematodes in the family Anisakidae. They parasitize fish (most commonly cod, salmon, herring, mackerel, haddock, pollock, and halibut) and squid and may be transmitted to humans who eat the undercooked or raw contaminated flesh. Ingestion of the larval anisakids may cause transient human infection and possible allergic reactions in susceptible individuals. Pseudoterranova were previously known as Phocanema and Terranova (as mentioned by Anonymous).
In the infected fish, P. decipiens are brownish in color, while Anisakis spp. are red-pink. Both are typically seen in the distinctive watch-spring coil shape, and are 1.5 - 2 cm long when uncoiled. For definitive identification, examination of internal structures, including the esophagus, are necessary.
To answer the second part of the question "Does this finding pose a risk to someone who consumes this fish?":
Anisakid larvae are killed by freezing, so this worm should be non-infectious if it had been thoroughly frozen. The FDA recommends that all shellfish and fish intended for raw consumption be blast frozen to -35°C or below for fifteen hours or be frozen at -20°C or below for seven days. Anisakiasis can also be easily prevented by adequate cooking at temperatures greater than sixty degrees (until the flesh is white and flaky). It is important to note that salting and marinating will not necessarily kill the parasites.