Seminiferous tubule number and surface: validation of objective parameters to estimate reproduction activity of male European anchovy (Engraulis encrasicolus, L.)
The present study aims to establish new quantitative parameters to objectively study reproductive activity in the male anchovy, Engraulis encrasicolus. The experimental design measured, at a microscopic level, the number (STN) and area (STA) of the seminiferous tubules during the reproductive season. This was conducted in relation to gonadosomatic index (GSI) and the five-degree macroscopic standard maturity staging of Brown-Petersen et al. (2011): immature, developing, spawning capable, regressing, regenerating. Fresh samples with a total of 200 fish were collected weekly during the reproduction season from October 2007 to May 2008 from commercial catches in the Gulf of Bejaia (Northeast of Algeria). Spermatogenesis activity is recorded by STN and STA values allowing the five Brown-Petersen stages to be distinguished and STN and STA also revealed accurately the different reproduction events during the study period (from October to May). In conclusion, the current results demonstrate that standardized STN and STA allow precise quantitative study of the reproduction activity of the male anchovy, and possibly in other fish species. The present method, based exclusively on histological slides biometry, could be recommended as a standard technique.