Ribonucleic acid and protein as indicators of seasonal growth variation in immature snapper (Pagrus auratus)

Abstract

Total ribonucleic acid (RNA) and total protein content were extracted from the white trunk musculature of wild immature snapper,Pagrus auratus, in order to evaluate protein synthesis as an index of somatic growth and to ascertain the possible effects of temperature fluctuations. Measurements of total RNA and protein from a population of wild fish were monitored over almost two years; they indicated seasonal variations in somatic growth rates that were significantly related to water temperature and body length. The highest values of RNA and protein were recorded in late summer, and were 4.0 and 47.7 g mg^–1 dry weight muscle respectively, whereas the lowest values appeared in winter, and were 2.1 and 32.8 g mg^–1 respectively (correlation coefficient = 0.8, P <0.0001). These results point to the potential of nucleic acid and protein measurements as indices of fine-scale variation in the growth rates of a commercially harvested species.