Influence of environmental factors on the life cycle and morphology of Artemia salina (Crustacea: Anostraca) in Sabkhet El Adhibet (SE Tunisia)

Abstract

Influence of environmental factors on the life cycle and morphology of Artemia salina (Crustacea: Anostraca) in Sabkhet El Adhibet (SE Tunisia) This study was aimed to examine in greater detail the influence of selected environmental factors on the life cycle and morphological characteristics of the brine shrimp Artemia salina (Linnaeus, 1758). During this follow-up, from November 2005 to April 2006 and from November 2006 to April 2007, Sabkhet El Adhibet (southeast Tunisia: 33°07'7.58"N, 11°24'8.69"E) was surveyed monthly to determine the impact of water salinity, temperature, pH, dissolved oxygen, and phytoplankton density and community structure on Artemia density, population structure, reproductive mode, and total offspring. Strong correlations were found between physicochemical parameters of water and Artemia reproduction characteristics. In contrast, no significant relationship was detected between physicochemical variables and Artemia population structure and density. Further, there were no correlations between phytoplankton density and the Artemia life cycle. Moreover, we observed relationships between physicochemical parameters and all morphological characteristics, especially between the width of 3rd abdominal segment and salinity (rxy = 0.96), temperature (rxy = 0.73), pH (rxy = -0.77) and oxygen (rxy = -0.92) for male specimens, and between the length of the furca and both salinity (rxy = -0.76) and dissolved oxygen (rxy = 0.74), and between the maximal diameter of compound eyes and temperature (rxy = -0.56) for female specimens. Principal component analysis (PCA) shows that male and female specimens collected at different environmental conditions converge, which explains the morphological similarity between them according to salinity, temperature, and dissolved oxygen concentration as well as total phytoplankton, diatom, cryptophyte, and dinophyte density.