International Journal of Marine Science, 2017, Vol.7, No.28, 275-283
277
To describe vertebral shape changes, the following five ratios from 7 vertebral measurements were calculated:
Length ratio = Dorsal length of the vertebra / Ventral length of vertebra for estimating wedging along vertebral
length;
Width ratio = Anterior width of the vertebra / Posterior width of the vertebra for assessing wedging along the
vertebral width;
Height ratio = Dorsal height of the vertebra / Ventral height of the vertebra for assessing the distortion of the
amphicoelous shape;
Thickness ratio = Middle line width of the vertebra / Posterior width of the vertebra for estimating the
mid-centrum thickness;
Slenderness ratio = Dorsal length of the vertebra / Posterior width of the vertebra for estimating the ventral
slenderness
All measurements were made to the nearest mm.
All specimens were deposited in the fish collection of the Faculty of Fisheries , Muğla Sıtkı Koçman University ,
Turkey.
2 Results
2.1 Scoliosis
The deformed
M. cephalus
specimen (Figure 2; Figure 3) showed a clear external sign of scoliosis, with the spine
curved sideway at 3 places compared with the normal specimen (Figure 4). The fish body curved started from just
anterior to the spinous dorsal fin and ended at the commencing
line of the caudal peduncle. The radiograph
(Figure 2B) showed that scoliosis deformity is clear even the x-ray was taken on the lateral side of the fish (Figure
3B). The radiography that revealed that there were 4 curvatures in the vertebral column, 2 curves to the right and 2
others to the left. The right curvature was the 1
st
from the head. The following vertebrae were involved in the 4
curvatures: 4
th
– 7
th
abdominal vertebrae (1
st
curvature); 8
th
– 11
th
abdominal vertebrae (2
nd
curvature); 9
th
– 14
th
abdominal
vertebrae (3
rd
curvature); and 15
th
abdominal – 6
th
caudal vertebrae (4
th
curvature). The angles between
the two lines passing through the sides of the curvature a, b, c and d were of 120°, 98°, 105°and 170 respectively.
The depth of the curvatures (DC) a, b, c, and d were: 3, 4, 3.5 and 1.5 mm respectively.
Figure 2 Abnormal
Mugil cephalus
, 291 mm TL
Note: A: external morphology; B: radiograph showing the scoliosis case
2.2 Pugheadness
The pug-headed
N. randalli
specimen (Figure 5A-C) had 150 mm Fork length (FL) and 130 mm SL, 4.2 mm
preorbital length and 10.2 mm postorbital length. This specimen was compared to normal fish having 175 mm
total length, 145 mm standard length, 5 mm preorbital length and 15 mm postorbital length.
