Age and growth of Antarctic Silverfish Pleuragramma antarcticum Boulenger, 1902, from the southern Weddell Sea and Antarctic Peninsula

Abstract

The length and age (determined from sagittal otoliths) of 1787 Antarctic Silverfish (Pleuragramma antarcticum) was analyzed from west of the Antarctic Peninsula (63°S/64°W) and southern Weddell Sea (73°S–77°S). Otolith diameter (D) was related to standard length by $$D (mm) = 0.011 x SL^{1.034} (mm).$$ Otolith diameters were between 0.1 mm (postlarvae) and 3.0 mm. The calculated growth from otolith readings indicated annual length increments of approximately 20 to 10 mm for fish from 2 to 12 years old. This low, but relatively constant growth is reflected in the Von Bertalanffy Growth Formula (VBGF) as $$L_t = 308 (1 - e^{ - 0.0715 (t + 1.15)} ) (mm).$$ Fish in the size range known from the Weddell Sea of 34 to 245 mm standard length are thus 1 to 21 years old. Growth Performance “P” of 1.1 is at the lower limit of values observed in Antarctic fish. In spite of low “k”, Pleuragramma antarcticum does not grow to large size. This finding is discussed in the light of adaptive demands of the species as a planktivorous pelagic nototheniid in the Antarctic.