Biology of the annular seabream, Diplodus annularis (Sparidae), in coastal waters of the Canary Islands

Abstract

The biology of the Canary Islands annular seabream Diplodus annularis (Linnaeus 1758) was studied from samples collected between January and December 1998. Fish ranged from 82 to 209 min total length in size and from 8.7 to 137.1 g in weight. The mean length showed an increase with increasing water depth. Males showed a negative allometric growth and females isometric growth. The species was characterized by protandric hermaphroditism. The overall sex ratio was unbalanced in favour of males (1 : 0.79). The reproductive season extended from January to May, with a peak in spawning activity in March-April. Males reached maturity at a smaller length (103 nim, 1-year-old) than females (128 nim, 2-year-old). Fish aged 0-6 years were found. The von Bertalanffy growth parameters for all individuals were: L-infinity = 247.9 min, k = 0.268 years(-1), and t(o) = -0.879 years.