Fróðskaparrit - 01.01.1995, Page 106

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WHALEWORM IN THE FILLETS OF SAITHE FROM FAROESE WATERS
Year Age M 1991 SD n M 1993 SD n M 1994 SD n
3 6,0 5,3 3 1,0 1,5 20 2,0 2,6 8
4 8,8 8,9 25 3,6 4,1 10 1,5 1,9 22
5 14,0 15,5 41 9,8 8,4 5 4,0 4,3 7
6 13,0 11,3 32 1,0 1 0,8 0,9 8
7 13,7 14,6 10 0,0 1 0,0 1
Table 2. Abdundance (M) and standard
deviation (SD) of Anisakis simplex larvae
in the fillets of age groups of aithe,
Pollachius virens, from the Faroe-Area. n:
number of fishes.
Talva 2. Miðaltøl (M) og standardfrávik
(SD) fyri Anisakis simplex ormverum í
upsaflaki hjá fylgjandi árgangum av upsa,
Pollachius virens. n: tal av upsa.
72.2 % and abundance 3.89 larvae per fish.
However, no larvae were found in the mus-
cles. This could be due to the technique
used, which was slicing and inspection on
candle table. The relatively small and trans-
parent larvae easily escape detection, like
in McClelland et al. (1990) who report a
loss of 68 % of Anisakis simplex in a visual
search, compared to pepsin-HCl-digestion.
The same authors found 5-10 % in the mus-
cles of the total Anisakis simplex burden in
Canadian saithe (”pollock”). Køie (1993)
reported Anisakis simplex third stage larvae
in the mesenteries and on the surface of the
intemal organs in 27 fish species from
Faroese waters. Six out of ten small saithe
(28-32 cm) were infected. Even if the larg-
er gadoids and some other fishes were only
examined in the viscera and head, the thor-
ough work of Køie op.cit. seems to point
out the difficulty in finding Anisakis sim-
plex in the musculature by visual examina-
tion.
The data in Table 1 and Fig. 1 show de-
creasing figures of larvae in the time period
1991-1994, both in prevalence (percentage
infected) and abundance (mean number of
larvae per fish examined). The high values
B
C
1,4%
right dorsal anterior
1,1%
right dorsal posterior
B+C = 2,5%
27,7% 7,5%
right dorsal anterior right dorsal posterior A+D = 35 2%
A
D
A
47,4%
left ventral anterior
D
12,1%
left ventral posterior
A+D = 57,5%
1,9%
left dorsal anterior
0,9% B+C = 2.8%
left dorsal posterior
B
C
Fig. 2. The distribution of Anisakis simplex lar-
vae in the fillets of saithe, based on 305 fishes.
The figure shows a filleted saithe, cut into the
eight parts, mentioned in the text (imagine you
are looking down onto the two halves of the
ftsh muscles). A-D: letter designation of the
different parts of the lateral muscles (bold num-
bers are percentages of total larval counts).
Mynd 2. Býtið av Anisakis simplex ormverum
í upsaflaki, grundað á 305 fiskar; dorsal: rygg-
partur; ventral: búkpartur; anterior: fremri;
posterior: aftari; left: vinstraflak; right: høgra-
flak. Myndin sýnir teir átta partamar, ið hvør
upsin var lutaður sundur í, aftaná at verða skor-
in til flak (á myndini sæst niður á ávikavist
høgra og vinstra flakið). A-D: bókstavanøvn
fyri teir ymsu partamar av fiskavøddunum (tøl
við tjúkkum stavum em prosent-virðir av saml-
aðum ormveru-tali).