Vertebral column deformity in adult wild haddock (Melanogrammus aeglefinus)

Abstract

This study describes radiological malformations in the vertebral column of adult sexually mature wild haddock, Melanogrammus aeglefinus collected from Masfjorden, Western Norway, in 2014 and 2015. There were seven deformed fish (33% of sampled fish), five with mild deformities and two with severe deformities. The deformity types discovered were lordosis, vertebra body asymmetry, compression, fusion (ankylosis), remodelling, and haemal spine hyperostosis. The two severely deformed fish were as follows: (a) one specimen with 29 deformed vertebrae within the region vertebrae nos. 1–30, including two sites of lordosis; (b) one specimen with 15 deformed vertebrae within the region vertebrae nos. 31–52 (most caudal vertebrae). The results of this study show that wild haddock can survive severe vertebra deformities, both in the trunk and tail region, and reach adulthood and sexual maturity. Whether normal nondeformed wild conspecifics would mate and spawn with these individuals and thereby complete the life cycle of the deformed individuals is, however, unknown. A possible link between bone fracture and fish hyperostosis is discussed.

Radiological changes during fracture and repair in neural and haemal spines of Atlantic cod (Gadus morhua)

“…To our knowledge, the only earlier report on calluses in fish is on callus formation in neural spines of pinealectomized salmon with a curved vertebral column (Fjelldal et al., ) and in haemal spines of wild adult haddock (Jawad, Hansen, Meier, Skaeraasen, & Fjelldal, ). In the latter study, a less radio‐dense stripe running in the transversal plane of haemal spine calluses was recorded, and it was suggested that the stripe may represent an area with low mineral content or cartilage, and that a fracture may have been involved in the callus formation.…”

Skeletal deformities in wild and farmed cleaner fish species used in Atlantic salmon Salmo salar aquaculture

“…In the presently studied wild fish, the L. bergylta had a vertebra deformity rate of 12% and C. lumpus 57%. Earlier records on vertebra deformity rate in wild fish have shown 3–43% in salmonids (Fraser et al ., 2014; Gill & Fisk, 1966; Sambraus et al ., 2014) and 6–33% in gadoids (Fjelldal et al ., 2009a; Jawad et al ., 2018; Wunder, 1971). Surveys on deformity rate in wild marine fish in Masfjorden, Norway, the area where the currently investigated wild L. bergylta and C. lumpus were collected, have shown 6% in G. morhua (Fjelldal et al ., 2009a) and 33% in haddock Melanogrammus aeglefinus L. 1758 (Jawad et al ., 2018).…”

“…Some of the studied L. bergylta had abundant callus formation, larger than the calluses reported by Fjelldal et al . (2018), but similar to those reported in M. aeglefinus (Jawad et al ., 2018) and striped piggy Pomadasys stridens F. 1775 (Jawad, 2013). Why bone fracture and calluses occur in ribs and neural and haemal spines in wild fish is unclear.…”

DNA damage and health effects in juvenile haddock (Melanogrammus aeglefinus) exposed to PAHs associated with oil-polluted sediment or produced water

“…Bone deformities in wild fish have for decades been used to monitor aquatic pollution [75][76][77]. Vertebral column deformity has been found in adult wild haddock caught in a Norwegian fjord [78], but no clear pollutant source was identified. In this study, we found an increased number of haddock with vertebra deformities from all three exposed groups compared to controls.…”