Gregarious behaviour of juveniles of the spiny lobster, panulirus argus (Latreille, 1804) in artificial shelters

The gregarious behaviour of juveniles (16-45 mm CL) of the spiny lobster, Panulirus argus in artificial shelters (concrete blocks), was studied in a nursery area in the southwestern region of Cuba. The average size of the juveniles was significantly different (df = 3; F = 796.60; P &lt 0.001) among the periods analysed (1982-1984, average = 45.90 mm CL; 1986-1988, average = 36.82 mm CL; 1989-1991, average = 37.33 mm CL; and 1992-1994, average = 39.46 mm CL) but it was not between sexes (df = 1; F = 0.3640 ns; P = 0.55). The proportion of males and females did not differ significantly from 1: 1 in sizes between 20 and 50 mm (CL). The sexes could be distinguished at a size of 16-20 mm (CL) and this was also the size-class that emerged from settlement places and adopted gregarious behaviour. As the source of immigrants to the nursery area was from the south, the southern shelters, located approximately 17 km from the barrier reef, were the first to be colonized. The highly significant relationship between the abundance of juveniles and pre-recruits (N = 13, R² = 0.8314, P &lt 0.001), suggests that the variations in abundance of the recruitment observed are displayed in all nursery areas. The high densities of lobster juveniles in nursery areas, their gregarious behaviour, their territorial migratory habits, and the evident decrease of recruitment to nursery areas in the Gulf of Batabanó from 1988 onwards, suggest that introduction of artificial shelters might help diminish natural mortality of post-pueruli and juveniles in these phases and increase recruitment to fishing areas. /// El comportamiento gregario de los juveniles (16-45 mm LC) de langosta espinosa Panulirus argus en refugios artificiales (bloques de concreto), fueron estudiados en un área de cría de la región suroccidental de Cuba. La talla media de los juveniles fue significativamente diferente (gl = 3; F = 796,60; P &lt 0,001) entre los períodos analizados (1982-1984, media = 45,90 mm; 1986-1988, media = 36,82 mm; 1989-1991, media = 37,33 mm; y 1992-1994, media = 39,46 mm, LC) pero entre sexos no lo fue (df = 1; F = 0,3640 ns; P = 0,55). Las proporciones entre machos y hembras no difieren significativamente de 1: 1 entre las tallas 20-50 mm (LC). Entre 16 y 20 mm (LC) se pudieron diferenciar los sexos y a partir de este intervalo se consideró que las langostas emergen desde los sitios de asentamiento y comienzan a tener un comportamiento gregario. Como la fuente de los inmigrantes al área de crí