Life-history traits of seabream Boops boops (Linnaeus, 1758) in the central eastern Atlantic Ocean (Canary Islands)

Abstract

Life-history traits of the sparid Boops boops are studied for the first time in an isolated Atlantic population. Boops boops is a hermaphrodite species  characterised by late gonochorism or non-functional hermaphroditism. The 1:0.852 ratio of females to males was significantly different from unity. Both sexes had similar size distributions; however, females outnumbered males at sizes of between 16 and 18 cm TL, whereas males predominated among fish larger than 28 cm TL. The average lengths at first maturity for females and males were 16.02 (SD 0.28) and 16.49 (SD 0.25) cm TL, respectively, with no significant difference between sexes. Spawning-capable females were first observed in January, at a low percentage, and were present until May. The gonadosomatic index of both females and males peaked in February. Vitellogenesis did not begin synchronously, and the simultaneous presence of oocytes in all stages of development indicated an asynchronous mode of ovarian development. The presence of  postovulatory follicles, together with tertiary-yolk-vesicle oocytes, indicates that the species is a multiple spawner. An age–length key showed an age-group composition for females of between 0 and 4 years, whereas males were between 0 and 5 years. The von Bertalanffy growth parameters for  females were L∞ = 32.3 cm TL, k = 0.44 y–1 and t0 = −0.81 y, and for males they were L∞ = 35.3 cm TL, k = 0.38 y–1 and t0 = −0.80 y.

Keywords: age, gonad histology, growth, maturity, otoliths, reproductive cycle, sex ratio, spawning period