Morphological malformations of the lateral line in reared gilthead sea bream (Sparus aurata L. 1758)

A general description of the morphological modifications of the lateral line in gilthead sea bream, reared under hatchery conditions, is provided. Farm-reared fish were examined and compared to wild fish. We used the presence of a pore on the specialized scales of the lateral line to determine the density and distribution of associated sensory neuromasts. The malformations of the lateral line were: zigzag with missing sector, wavy with missing sector, several scattered missing sectors, and several consecutive missing sectors. These abnormalities occurred in 71.0-86.2% of the reared fish, depending on the hatchery. They did not occur in wild fish. The possible behaviour consequences for gilthead sea bream of deficient sensory reception are considered. in addition, the suitability of these abnormalities for use as individual markers in different types of studies is proposed. (C) 2001 Elsevier Science B.V. All rights reserved.