2 Results

The anomaly fish has the following body measurements: 135 mm total length; 115 mm forked length; 104 mm standard length; and 36 mm head length.

Morphologically, the fish body is distended ventrally in the area of the caudal peduncle starting from the posterior tip of the anal fin to the base of the caudal fin (Figure 1). The two skeletons of the normal and abnormal specimens were compared (Figure 3). Two flexions of the vertebral column were observed, one in the abdominal region and the other in the caudal region of the vertebral column.

The uprising part of the arch is formed of the abdominal vertebrae 6-9 and the descending arm is formed of the caudal vertebrae 4-8. The caudal vertebrae 1-3 are on the top of the arch with curved centra. The anterior part of the centrum of the 1^st caudal vertebra shown raise upward.

The ratio of the vertebral column to the total length of the deformed specimen is 0.5, while it is 0.9 in the normal specimen. The value of the angle “A1” is 92°. The depth of the curvature of angle “A1” is 10.4 mm. The value of the angle “A2” is 110° and the depth of the curvature of angle “A2” is 5.3 mm. The value of the angle “A3” is 103˚ and the depth of the curvature of angle “A3” is 8.3 mm.

The 9^th abdominal vertebra and 2^nd- 5^th caudal vertebrae have showed an increased in their height on the ventral side (0.021 and 0.023-0.025, respectively) (Figure 3B) and reduced on the dorsal side (1.130 and 1.135-1.256, respectively). Abdominal vertebrae 5 and 6 are wedged (1.245-1.265) (have a reduced ventral length relative to their dorsal length). The 6^th abdominal and caudal vertebrae have reduced midline widths (0.023 and 0.029). The caudal vertebrae 1-4 are wedged such that the dorsal length is reduced relative to the ventral and the amphicoelous centra of the 9^th abdominal vertebra and caudal vertebrae 2-5 are distorted such that the height is increased on the dorsal side (0.002 and 0.002-0.003). Slenderness and thickness were less in abdominal vertebrae 7-9 (0.001-0.003) and in caudal vertebrae 4-10 (0.002-0.005) (Figure 3B).

The fish specimen also showed a deformed pre-operculum and operculum bones, where the surface of these two bone appeared to be heavily scratched. The last 3 lateral line scales appeared distorted. Due to the curvature caused by angle “A1” the dorsal profile of the body below the dorsal fin appeared slightly curved.

No other anomalies were observed on the body of the fish.

3 Discussion

This is the first study investigating the lordosis-kyphosis-ankylosis deformities that are observed in the examined adult wild teleosts Mullus barbatus from the Turkish waters. Anomalies in wild fish species have been well documented (Jawad et al., 2013; Jawad and Liu, 2015), where the causes of different deformities have been presented. Such causes include both genetic (Ishikawa, 1990) and epigenetic factors (Fjelldal et al., 2009), as well as environmental factors (Gavaia et al., 2009).

Structural indication was presented in the x-ray taken for the specimen (Figure 3B) that the normal shape of vertebrae is distorted. In addition, vertebrae at the estimated apex of curvature (lordotic vertebrae) are impacted so that the length on the concave side of the curve is decreased relative to the convex length. For some of the vertebrae, the midline width is appeared to be significantly. Such changes were observed by Gorman et al. (2010). Jardas and Morovic (1975) reported scoliosis and kyphosis cases in M. barbatus from the Adriatic Sea. In the kyphosis case they reported, the vertebrae were not deformed as in the case given in the present study. Therefore, the fish in our study experienced a severe abnormality than those of Jardas and Morovic (1975).

Any deformity in the shape of the vertebrae, which include remodeling will have a direct impact on the swimming ability of the fish and its survival (Başaran et al., 2007), and there was a significant relationship between the lordosis severity and swimming performance in sea bass (Dicentrarchus labrax) at least in juveniles (Sfakianakis et al., 2006; Peruzzi et al., 2007).

The multi-cases of vertebral fusion observed in the present study can be explained as a result of the study of Ytteborg et al. (2012). It might be possible that the deformed specimen of M. barbatus has lived in an unfavourable environmental conditions that might cause this type of vertebral abnormality. The case of the deformation was not fatal since the deformed specimen was an adult, but it certainly affected the mobility in some way. Except for the distorted two dorsal fins, the other fins were found in apparently in perfect condition.

From the present study, it is clear that the fish teratology is very complex and cannot be attributed to a single factor but it would have been due to the effect of multiple factors such as pollution, salinity fluctuations, low level of dissolved oxygen, radiation etc.

It is obvious that any morphological anomalies in any fish specimen offered from sale I the fish market will pull away the buyers. Therefore, there will be a commercial impact on the fishermen that happened to have deformed samples. For such reason and to decrease the presence of the deformed specimens among the fish offered in the market for the sale, further efforts such as enhancements of administration of the fisheries industries should be made to discover the various etiological causes of the anomalies before further serious choices are made.

4 Conclusion

In conclusion, there is a good possibility for the anomalous cases of lordosis, kyphosis, and ankylosis to occur in one fish specimen and such specimen could survive these vertebral deformities and reaches to the adulthood. Since these types of vertebral column abnormalities have shown to be related to pollution in other fish species, further studies are needed to relate specific pollutants with the observed types of deformity.

Authors’ contributions

All authors have contributed equally toward the publication of this paper.

Acknowledgments

The authors would like to thank Faculty of Fisheries, Ege University, 35440 Urla, Izmir, Turkey for using its facilities during this study.

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