Studies on Reproductive Biology of the Red (Blackspot) Seabream [Pagellus bogaraveo (Brünnich, 1768)] from the Strait of Gibraltar (ICES IXa/SW Spain)

Abstract

Reproductive biology of the Red (blackspot) seabream (Pagellus bogaraveo) was studied throughout monthly samples from landings of artisanal fleet (“voracera”) in the fishing ports of Tarifa and Algeciras (Cádiz, Spain). For each specimen sampled, the total body length, total and gutted body weight and gonad weight were recorded. The number of males, females and hermaphrodites and its gonad macroscopic stages of maturation were recorded too. Some ovaries were dissected, fixed in formaldehyde (4%) and embedded in hydroxyethylmethacrylate for a later histological examination. Sex ratio (by month and by length class) seems to reflect a proterandric hermaphoditism. Spawning period (from GSI estimation) was located in the first quarter of the year and also maturity lengths were estimated for males and females (30.14 and 35.72 cm, respectively). On basis of the overall gonad histology, five distinet stages have been identified throught the process of ovarian maturation. Finally the fecundity of P. bogaraveo was calculated throught stereological methods in females with ovaries in stage III and IV.