Embryonic development and fecundity of the squat lobster Munida gregaria (Decapoda, Galatheidae) in Northern Patagonia

DELLATORRE, FERNANDO GASPAR; GONZALEZ-PISANI, XIMENA

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

CAMBRIDGE UNIV PRESS

Año: 2010 p. 1 - 10

0025-3154

In this study, fecundity of Munida gregaria in Northern Patagonia was analyzed in relation with size and compared with other studies in different sites along its latitudinal distribution. Also, morphological changes in embryos reared in laboratory, and the chronology of its appearance were observed. Fecundity (total number of eggs in a clutch) was strongly correlated to size (carapace length in mm) (R = 0.638) and the regression equation fitted by least squares was Log(F) = -1.37 + 3.85 * log(CL). Size specific fecundity was higher than in southern locations along Patagonia. Recently extruded eggs are smaller than in southern Patagonia measuring an average of 530 µm in diameter and 0.043 mm3 in volume. When ready to hatch, those measures increased by 30% and 50% respectively. Complete embryonic development lasted an average of 27.9 days at fixed temperature of 11°C. Five development stages were defined based on morphological changes: 1) from fertilization to the appearance of embryonic primordium (2-3.5 days), 2) embryonic tissues occupying less than half of the egg perimeter in lateral view (7-10 days), 3) embryonic tissues without pigments and occupying more than half of the egg perimeter in lateral view (5-8 days), 4) Embryos with reddish eye pigments and chromatophores (4-6 days), and 5) Ocular globe completely pigmented (3-4 days).