Skeletal deformities and juvenile quality.

Mass rearing of Sparidae juveniles is at present a reality, but relatively low survival rates (20-30%) and suboptimal quality too often characterize commerciai juvenile production. Therefore, one of the bottlenecks of the Sparidae aquaculture industry is the presence of morphological deformities, which result in major economie losses due to mortalities, reduced growth, or unmarketability of the final product. Deformed fingerlings need to be manually selected and eliminated, but current sorting methods do not eliminate completely the presence of deformi ti es in the ongrowing phase, and further sorting is needed before fish are marketed for food. Different types of skeletal deformities, body malpigmentation, malformed scales or lateral line, anomalous shape, abnormalities in the olfactory organ, eye cataract, and infiammation are reported in cultured Sparidae fishes. The causes reported for these morphological anomalies are many and only partially understood. Basically, there are as many causative factors as there are biological fields: genetic, nutritional, physiological, physical, chemical, biomolecular, and environmental causes have all been blamed for inducing pigmentation or skeletal anomalies in fish but, at the end, it is stili possible to state that the same typology of skeletal anomaly may be due to different causes, but also that different causes may produce the same type of anomaly. Up to now, the available data seem to indicate that anomalies are the consequence of so many infiuential and interacting factors, that interdisciplinary studies combining anatomie, genetic, and biomolecular data, with physiologic data on larval welfare conditions will probably be necessary.