The importance of the mesh size for the extraction of the muddy bottom meiofauna 1

A set of five screens (mesh apertures: 100, 80, 63, 50, and 40 µ) was used to sort twelve samples collected from fine gray terrigenous mud, at 32.5‐m depth. The data show higher counts (2,917–8,881 individuals 10 cm −2 ; annual avg = 4,855) than those previously reported by others from similar areas. Substantial variations in the percentage of extracted fauna are observed through the year. In most cases, the 100‐, 80‐, and 63‐ µ screens retain 90% of the meiofauna. A 40‐ µ mesh is necessary to study the dynamics of the nematode population; at certain times more than 30% of the individuals of some species may pass through a 50‐ µ screen.