Publication Date:
2021-05-19
Description:
In this research, the potential use of five hard parts (otolith, scale, eye lens, dorsal spine, vertebral bone) of
Rutilus kutum for stocks discrimination and biomonitoring as well as their usability as biological archive in the
southern Caspian Sea was investigated. Two soft tissues (muscle and liver) were also analyzed for assessment of
the possible risk of consumption and use as biomonitoring tool, respectively. A total of 60 specimens were
collected using beach seine from three sampling sites (adjacent to the estuaries of the rivers Sefidrud, Tajan and
Grorganrud, respectively) in the Southern Caspian Sea in May 2016. In total, the levels of 13 major and trace
elements in the samples (the seven soft and hard tissues) was measured using PIXE (Proton Induced X-ray
Emission) and µ-PIXE methods.
Generally, the pattern of elements occurrence in the eye lens was considerably different compared to the other
hard parts. The orders of element occurrence in the two soft tissues were largely similar, but Sr was not
detectable in muscle. Ca, Fe, S, Cl and K could be detected in all the selected tissues, while Br was detectable
only in otolith.
Minor similarities among the tissues were observed in the case of eye lens (for P, S and Zn) and liver (for Cl, Fe
and K). Whereas, in the case of Sr and Ca, otolith shows the maximum distance. On the other side, in the case of
K, the soft and hard parts could be categorized into two completely separate groups.
Generally, vertebral bone and liver showed the highest and lowest number of the correlation pairs, respectively.
In case of all the hard parts, very strong correlations were found between S and Cl. Among them, all the
correlations, except for eye lens, were positive. There were no significant relationships between the elements and
biological characteristics (weight, total length and standard length).
Based on the results, it seems that all the studied hard parts, except for eye lens, may offer alternatives for
biomonitoring of Ca, Cl, Fe, K and S in the southern Caspian Sea. The scales and spines represent a potential
non-lethal alternative to the other hard parts. However, since fish physiology regulates the uptake and
incorporation of some elements, it is not clear that levels of all of the mentioned elements reflect their variability
in the environment.
Considering Sr level in otolith, no significant differences could be found between the sampling sites 2 and 3. So
it can be concluded that the specimens collected from the two sites are probably from the same population.
Similar results were also obtained based on the results concerning K accumulation in scale. It can be concluded
that scales may provide an alternative structure to otolith for stock discrimination of R. kutum in the southern
Caspian Sea.
Considering the µ-PIXE elemental distribution maps and their comparison with the annual growth increments on
the five hard parts, no clear patterns could be detected. In other words, the used the method seems to be not
sensitive enough to characterize of the elements concentrations based on the growth patterns. Therefore, the
capability of other analytical methods (with higher resolution) in clear differentiation of the growth patterns
should be evaluated in future investigations.
Among the 10 elements that were detectable in the muscle using the PIXE method, only in the case of four of
them (i.e. Zn, Cu, Fe and Mn) maximum allowable concentrations for human consumption have been defined,
which in all the cases the mean concentrations in the present study were far below the recommended limits and
accordingly it seems that in this regard there is no risk for human consumption of flesh of the fishes.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Kutum
;
Bio-archive
;
Fingerprinting
;
Non-destructive analysis
;
Evaluation
;
Fish species
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
54pp.
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