Skeletal deformities have been observed in cultured flounder in recent years. At times, high percentages of fish are affected, potentially influencing growth and marketability, and affecting the reliability of the experimental data collected. Many growers taking fish for pilot scale grow-out trials reported mortality and low growth in many fish with gross skeletal deformities. Although skeletal (spinal) deformities are of most concern, mal-pigmentation or pseudo-albinism is also significant. It is likely that nutritional deficiencies/imbalance are responsible for these conditions but as the nutritional requirements of this species are unknown, the causes are unidentified. Deformities in the past have been observed in fish larger than 5-10 g. It was the aim of this study to identify the timing of the appearance of the skeletal deformities during a documented larval/juvenile rearing period and to trial alternative production protocols. It was outside the scope of this study to identify the causes of the deformities. The results show that deformities are visible after a period of time on artificial diets, during the post-weaning period Deformities were not evident during the live feed period.

The main objective in the detection of the spinal deformities was achieved but the manipulation of diet and environment was only achieved on a superficial level. Future work in this area would need to consider the complex interactions between temperature, live feed enrichment, weaning and artificial diet composition.