International Journal of Aquaculture, 2017, Vol.7, No.11, 79-82
81
4 Discussions
In the present deformed specimen, the anomalies represent a deformed neural and haemal spines of a number of
caudal vertebrae. The abnormal calcification in the 1
st
location of deformity can be as a result of disorganized and
proliferating cells at the growth zones. Similar case was observed in the vertebrae of fishes by Ytteborg et al.
(2012). On the other hand, Cockroft (1978) and Miura et al. (2004) have given examples, based on several
mammalian cases, on the changes in the balance between cell death and cell proliferation may lead to
malformations. In the growth process of the bony elements, increased growth of osteoblasts at the development
zones is partly stabilized by increased cell death (Ytteborg et al., 2012). In the present case of abnormal
calcification can be due to destabilization in the cell death.
It might be possible that the deformed specimen of
H. fossilis
has faced an unfavourable environmental factors
that might cause this type of skeletal abnormality. Since this specimens is an adult, then the deformation in was
not fatal, but it certainly affected the mobility in some way.
The wavy neural and haemal spines of posterior caudal vertebrae could be as a result of an adverse environmental
factors (Jawad et al., 2014; 2015). Among these unfavourable environmental factors is the pollution with heavy
metals, which approved to be one of the main agents in developing fish malformation (Chatain, 1994; Gavaia et
al., 2009). The Ganges River passing through heavily populated settlements as with the case of the large rivers of
the world. As a result, the water of this river became heavily polluted by different types of pollutants including
heavy metals (Kannan, et al., 1993; Singh, 2001; Singh et al., 2005).
Lack of certain nutritional component such as phospholipids might be considered a possible cause for the skeletal
deformities in
H. fossilis
. Kanazawa et al. (1981) showed that phospholipids reduced skeletal deformities in larvae
of Plecoglossus altivelis and phosphatidy linositol reduced spinal malformations in larval
D. labrax
(Cahu et al.,
2003). On the other hand, excess of phospholipids induced severe skeletal malformations in larval
D. labrax
(Villeneuve et al., 2005).
The mechanical factors in producing such anomalies cannot be excluded. Hilomen-Garcia (1997) has studied the
fish larvae in the rearing tanks and the mechanical injuries they usually face. Koumoundouros (2010) has
suggested that the mechanical load can cause lordosis in the vertebral column of the fish. Finally, Boglione et al.
(2013) have mentioned the mechanical factors in causing skeletal deformities in different European fish species.
References
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