Fróðskaparrit - 01.01.2008, Blaðsíða 154

152
PARASITES OF THREE-SPINED STICKLEBACK, CASTEROSTEUS ACULEATUS L
FROM FAROE ISLANDS
Fig. 1B Sticklebacks from Faroe Islands, Aug. 2003
(marineform, Rituvík).
is that of Katsiadaki (2007) which includes a
short section on including parasites in such
monitoring.
The primary goal of this work is to pro-
vide baseline data on the parasites of stick-
lebacks in the Faroe Islands. This work may
then be applied to both evolutionary and
environmental questions in the future.
MATERIALS AND METHODS
Sampling sites (Fig. 1 A). Samples were ob-
tained from the three islands of Streymoy
(Kaldbak = KA), Eysturoy (Rituvík = Rl, Kráar-
gil = KR, Toftavatn = TO and Klubbatjørn =
KL) and Borðoy (Skúvadalur = SK). The sam-
pling design (randomized blocks, 3 x 2) is
comprised of three marine (KA, RV and KR)
and three freshwater environments (TO, KL
and SK). The two salinity groups represent
the variety in area and height found in each
group on the Faroe Islands. Sticklebacks were
caught in traps (large lakes) or with nets
(shallow and small ponds). A total of 1105
fish were examined, rangingfrom 35-101 fish
in each sampling. From each site a total of
130-249 were sampled in the time period
2002-2004.
Temperature was measured 10 cm be-
lowsurface (range 11.5-21.8 °C). Salinity was
determined by an "Autosal 8400A Cuild-
line"- apparatus (range for saline sites was
0.222-34.954 psi, and 0.0605-0.1405 psi for
freshwater sites).
Treatment ofsamples. Sticklebacks were kil-
led in approx. 18% formaldehyde, then im-
mediately diluted to approx. 6% formalde-
hyde and stored for further examination.
Examination offish. The sticklebacks were
measured in mm (total length) and weighed
to milligram, thus giving the possibility of
condition factor studies. The status of the
plates were recorded as "low-plated" (leiu-
rus), "partially-plated”(semiarmatus) or
"whole-plated" (trachurus), the second spine
setting the limit between low- and partially
plated. For a detailed explanation of plate
morphology see Wootton (1976). Also the
keel in the tail region was recorded, if pres-
ent. External and internal inspection for par-
asites was carried out on a dissecting scope
at 16x, followed by light microscopical ex-
amination when necessary. After dissection
each fish and its parasites were stored in 70
% ethanol. Thersitina gasterostei and Tri-
chodina sp. were occasionally stained in
“Quick-stain” for microscopy or microph-
otographing.
Statistical tests used were: two-way
ANOVA, Chi-square-test and paired sign
test.