SEASONAL CHANGES IN THEINFECTION OF YOUNG SAITHE
Among the Faroese public as well as in oth-
er fish-consuming countries it is a general
view that the infection of fishes with nema-
todes exhibits seasonal changes (pers. ob-
servations). It is well documented that
prevalence of infection (percentage infect-
ed) and intensity of infection (mean num-
ber of parasites per infected fish) with
Anisakis simplex third stage larvae is in-
creasing with age for several fish species
(Wootten, 1978; McClelland et aZ.,1990).
Thorough work dealing with parasites of
saithe like that of Scott (1985) or Polyans-
ki (1966) did not examine the effect of sea-
sonality in detail, however.
The investigations of fishes for nema-
todes usually are made in age-classes enter-
ing commercial fishery, leaving the
younger age-classes relatively unexam-
ined. Juvenile and young saithe is staying
close to the coast, while the maturing age-
classes do emigrate to deeper waters (Joen-
sen and Táning, 1970). This makes it diffi-
cult to catch juvenile or young físh with the
common research vessels or commercial
Infection of adult saithe from Faroese
Waters with A. simplex in fillets was exam-
ined by Højgaard (1995a; b) and the pre-
sent study is a continuation of this work.
The aim was to search young saithe for par-
asites and to relate the infection with time
of the year.
Materials and methods
Young saithe was caught close to Leirvík,
Faroe Islands from Jan to Dec, 1996 (Table
1). The sampling area is presumed to repre-
sent common Faroese bays and sounds,
which are characterized by severe tidal cur-
rents, giving ideal conditions for young
saithe to gather in schools and browse on
the incoming zooplankton. The fish was
caught at dawn with nylon longlines, opera-
ting from a traditional Faroese fishing boat.
The distance to the coast was 50-300 m,
bottom depth 10-60 m and físhing depth
were approximately 1-7 m. Immediately
after the sampling, the físh was weighed,
the length was measured and the otoliths
were removed. The whole fish were deep
frozen in separate plastic bags at -18 °C.
Table I. The samples of saithe froin the Leirvfk area, January-
December 1996, positions close to 62°15' N, 06°40'W.
Talva 1. Tikin sýni av seiði úr Leirvíksfirði frá januar
til desember 1996
Date Number of saithe
After a thawing period of 6-12 h, butterfly
fíllets were cut from the saithe and the
stomachs were refrozen. Digestion of the
fillets without skin and the viscera in
pepsin-hydrochloric acid were made in 2 L
or 1/2 L beakers, respectively, at 37 °C for
3-6 h, pH 1-2 (Smith and Wootten, 1975).
The fillets were digested with continuous