Effects of temperature on the growth and microstructure formation of cuttlebone from cuttlefish Sepia pharaonis

Abstract

ABSTRACTThis study investigated the effects of three temperatures (20°C, 27°C, and 31°C) on the physiological performance (survival and growth) and cuttlebone micromorphological features (chamber number, chamber height and lamellae number) of cuttlefish Sepia pharaonis. We examined gross morphological characteristics of the internal calcareous cuttlebone to determine whether lamellar matrix was impacted by temperature. Juvenile survival was significantly affected by temperature (χ2 = 54.580, df = 2, P < 0.001). Cuttlebone weight, length and width were also positively correlated with temperature. Scanning electron microscopy revealed that a single chamber structure consists of septa, lamellae and pillars. At 20°C the chamber number of 89.0 ± 10.8 was significantly higher than at 27°C with 44.8 ± 3.6 or 31°C with 47.5 ± 4.3 (Kruskal–Wallis [KW], χ2 = 26.391, df = 2, P = 0.0001), whilst chamber height was lower at 20°C (KW χ2 = 27.842, df = 2, P = 0.0001). Moreover, lamellae number varied among the treatments (KW χ2 = 22.411, df = 2, P = 0.0002). Lamellae numbers at 20°C, 27°C and 31°C were 3–6, 6–9 and 5–8, respectively. The results indicated that the intrinsic lamellar matrix structure was significantly affected by temperature and that this effect may be used in cuttlebone growth studies.