The interest in Holothuria tubulosa (Gmelin, 1788) is linked to a lack of data on its reproductive cycle and biometrics in Algeria. The choice of the tubular sea cucumber is based on the fact that it is the most abundant species in the Mediterranean and even in Algerian waters. Its biological cycle, and especially its reproductive cycle, offers an interesting field of investigation. Our study covers six months of sampling of Holothuria tubulosa (Gmelin, 1788) carried out at three sites on the west coast of Algeria with different substrates, namely Madrague, Ain Franin, and Cap Carbon. The study has two main focuses: monitoring physiological fluctuations in 321 specimens and correlating different weight and linear measurements of H. tubulosa (Gmelin, 1788).