Reproductive biology and energy allocation of the seastar Cosmasterias lurida (Echinodermata: Asteroidea) from the Beagle Channel, Tierra del Fuego, Argentina

COSSI, P.F.; BOY, C.C.; GIMÉNEZ, J.; PÉREZ, A.F.

POLAR BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2015 vol. 38 p. 1321 - 1333

0722-4060

Reproductive cycle, the pattern of gonad and somatic indices and variation in energetic content of organs were studied in the asteroid Cosmasterias lurida from the Beagle Channel (Tierra del Fuego, Argentina) between August 2010 and June 2011. Histological sections of gonads were made for sex identification and gametogenic stages were defined. Energy content determinations were done through complete combustion in a calorimetric bomb. Gonadal index (GI) was significantly higher in autumn and winter than in spring and summer, with a strong declination between winter and spring suggesting a spawning period. Highest GI values of mature individuals were observed in winter followed by a rematuration period of lower intensity during spring and summer. GI showed a negative correlation with water temperature, which could indicate an association between temperature and gametogenesis, gonadal development and releasing of gametes. Percentage of organic matter in the body wall and stomach and pyloric caeca energy density (EDS, EDPC) showed higher values during autumn suggesting a role of these organs as energy reservoirs for winter survival and/or for gonadal maturation and spawning. Higher energy content in ovaries than in testes indicates a greater energy investment for gonadal maturation by females. Finally, the lower GI values found here in relation to a northern population of the species could be consequence of a trade-off between gonadal maturation and other activities (such as growth and survival) which deserves future studies.