Contribution à l'étude biométrique de l'oursin commun Paracentrotus lividus de la côte de Mostaganem.

Abstract

The edible sea urchin Paracentrotus lividus (Lamarck, 1816) has a geographical distribution, which includes the Atlantic Ocean and the entire Mediterranean Sea. It is the subject of numerous studies dealing with the biology of this species. Samples of specimens were taken at a depth of between 1 m and 3 m during the month of February 2020 in two types of biotopes, Stidia considered to be a very active sector and which receives several sources of anthropogenic pollution and Abdelamek ramden (named Clovis) which relates to him considered as the reference area. The results could highlight an imbalance in the male / female sex-ratio at the two sites. The percentage of females is much higher than that of males with a percentage of 62% in Clovis and 40% in Stidia. Males correspond to 20% in Clovis against 23% in Stidia. The Physiological Indicators (IRm and IGm), display important differences that appear depending on the study site during the month of February. The study of biometric relationships shows a lower allometry on all the sites but also for the two combinations of the studied parameter, thus translating that the height of the test pushed less quickly than the diameter and that the total fresh weight of the pushed sea urchin, also slower than the height of the test. The co-evolution of the parameters height-diameter as well as total weight-height displays very good correlation coefficients (r) is ranging from 70% to more than 80% and this for the two study sites (Clovis and Stidia) and for the two size classes taken into consideration. The sea urchin shows good development, whether in a polluted or reference environment.