Reproductive biology of wahoo (Acanthocybium solandri) in the Canary Islands (eastern-central Atlantic)

Abstract

The reproductive status of wahoo (Acanthocybium solandri) in the eastern-central Atlantic was investigated to better understand their migration and breeding patterns. The waters around the Canary Islands are considered a breeding area for wahoo; and this study documents the first described breeding activity found in the eastern Atlantic. The presence of many mature and spawning capable wahoo reported in this study confirms its spawning activity in this region. Off the Canary Islands, only mature individuals spawn in the region where no immature individuals were observed to date. Most of the specimens captured in Canary Islands waters exceed 100 cm TL (about 2 years old). Values of the gonadosomatic index (GSI) of males were much lower than those estimated for females. Testes showed little changes in size throughout gametogenesis, while ovaries increased significantly (p<0.05). The low values make it inadvisable to use GSI in males to determine spawning activity. In the Canary Islands, wahoo females spawn (fishes with tertiary vitellogenic oocytes, postovulatory follicles or germinal vesicle migration, yolk coalescence, germinal vesicle breakdown and hydrated oocyte) mainly during a 4-month period in summer. Both females of spawning capable outside the main summer breeding period and females in regressing phase during the spawning period have been observed in the Canary Islands. Males were found in the spawning capable phase throughout the year, with greater prevalence between May and October.