International Journal of Aquaculture, 2017, Vol.7, No.7, 51
-
56
52
2017). The conservation status of this species has not been evaluated and since the distribution of this species is
confined to Sri Lanka, the unfavourable environmental factors might make it vulnerable and threatened. Therefore
it is important to report about the any abnormality that might occur and might cause death to the individuals of
this species. The present study aims to: (1) to describe for the first time a case of lordosis in
P. kamalika
collected
from Sri Lanka; (2) to describe this anomaly and compare them with those of the normal individuals. The damage
at both the histological and the cellular stages was not determined and left for a future detailed study which will
take into consideration comparison of the normal and abnormal specimens.
2 Materials and Methods
One adult specimen of
P. kamalika
was collected on 30
th
December 2014. This specimen appeared with severe
case of lordosis, which was collected from the Western Province, Colombo District, Bolgoda drainage, stream at
Mawathgama, running through paddy fields N 6°49'34" E 80°0'42" using drag net at depth of 450 mm (Figure 1).
Table 1 shows the measurements of the abnormal specimen. Radiography was used to examine the skeleton of the
fish to describe the anomaly. The ratio between the length of the vertebral column (anterior edge of the 1
st
vertebra to the posterior edge of the last caudal vertebra) and fish total length was used to show the difference
between the normal and abnormal specimens. Using a digital protractor, the angle found in the centre of the
lordotic vertebral column was measured. To calculate the formula of Louiz et al. (2007) that measure the depth of
the curvature (DC), the height of the vertebral column (HC) was measured, which is resembles the distance
between the apical line of the vertebra and the base of the vertebra at the centre of the curvature. The formula of
Louiz et al. (2007) I usually used to evaluate the level of deformity in the lordotic specimens. The length
measurements were made using digital caliper with accuracy of 0.01 mm. The Louiz et al. (2007) formula is:
DC = (HC / SL) ×100 (SL = standard length fish)
Figure 1 Map showing the collection area
Chapleau (1988), Ramzu and Meunier (1999), and Nowroozi (2012) have defined the abdominal and caudal
vertebrae as those vertebrae with haemal spines and located directly posterior to the skull, and those vertebrae
with fused haemal spines respectively.
As with humans, the length of a vertebra is described as parallel to the cranial- caudal axis, and the width is
perpendicular.
To describe vertebral shape changes independent of individual size differences, five ratios from 7 vertebral
measurements were calculated.
