The data of Phycis blennoides comes from bottom-trawl surveys (2003-2004), caught between 170 and 779 m along the Algerian coast. Additionally, commercial fish samples of P. blennoides were obtained from 11 Algerian ports between 2013 and 2017. The dataset presented is composed of:

• Biological parameters of commercial specimens across seasons: mean values of gonadosomatic index (GSI), hepatosomatic index (HSI) and somatic condition factor (K) for males (M) and females (F) (File: Commercialfisheries.xlsx).
• Percentage of maturity of each gender collected from commercial specimens to build the length at first maturity (L₅₀) (File: Commercialfisheries.xlsx ).
• Density, biomass, meanweight (File: data.xlsx) across bathymetric strata and year with the R-code (ullagraph).
• Density, biomass and meanweight of Phycis blennoides across longitude caught in 2003 (File: gam_03.csv) and 2004 (File: gam_04.csv).
• The R-code (moigamm) to reproduce the generalized additive model (GAM) of density (ind/km²) and biomass (kg/km²) of P.  blennoides with longitude (°) caught in 2003 and 2004.