A study of the migration of larval Anisakis simplex (Nematoda: Ascaridida) in the Chilean hake, Merluccius gayi (Guichenot)

Hake were collected during four trips to investigate a possible migration from viscera to somatic musculature of larval Anisakis simplex. On each trip 150 hake were examined and separated in five groups of 30 hake. One group consisted of fish gutted immediately after capture; two other groups were gutted 15 h after capture, one of which had been left at environmental temperature, and the other put in ice; the remaining two groups (exposed to the same treatment) were gutted 30 h after capture. All fish flesh was digested (HCl-pepsin digest); all nematodes found in the digest and in the viscera were counted. There was no increase of larval nematodes in flesh at 15 and 30 h. Temperature did not affect the migration of larvae. A regression test did not show significant differences between groups. Finally, there was no correlation between number of larvae in viscera and in musculature.