Reproductive Biology of Male European Hake (Merluccius merluccius) in Central Mediterranean Sea: An Overview from Macroscopic to Molecular Investigation
Alessia Mascoli; Michela Candelma; Alberto Santojanni; Oliana Carnevali; Sabrina Colella;
The improvement of scientific knowledge about overexploited fishery resources allow us to
provide scientific advice for their management and stock protection. By using a multidisciplinary
approach, the aim of the study was to characterize, for the first time in the Central Mediterranean Sea
(GSA 17), the reproductive biology of males of M. merluccius, currently highly exploited. A multi-year
sampling from January 2017 to December 2019 was performed to exhaustively evaluate the sex ratio
of the stock, while the 2018 annual sampling was selected to investigate the reproductive pattern
of males. Individuals in spawning conditions were found every month, proving that M. merluccius
is an asynchronous species, reproducing all year round, with a seasonal reproductive peak in
spring/summer, as indicated by GSI. Five gonadal development stages were defined to fully describe
the reproductive cycle of males. The macroscopic and histological L50, respectively 18.6 cm and
15.4 cm, were both below the Minimum Conservation Reference Size (MCRS). According to the
mRNA levels, fsh and lh played a significant role during spermiation, whereas the gnrhr2a was
involved at the beginning of sexual maturity. In the testis, fshr and lhr reached maximum expression
levels before the spermiation. The hormonal stimuli of 11-ketotestosterone and its receptor were
significantly higher when the specimen was in reproductive activity
2023 - Journal article
Biology (Basel) 12 (2023). doi:10.3390/biology12040562
Keywords: Merluccius merluccius, Male reproductive pattern, Histological analysis, Somatic indexes, Reproductive regulation, Central Mediterranean Sea