Abstract.-The distribution and abundance of Octopus bimaculatus paralarvae and juveniles in the Pacific South of Mexico (i.e., 14 to 16°N) are described. A total of 15 paralarvae were collected during three plankton surveys in July, September and November 2001. Size of paralarvae ranged from 0.7 to 2.7 mm Dorsal Mantle Length (ML), with the smallest size corresponding to the ML at hatching. Additionally, three juveniles were collected by scuba diving in a coastal area in 2010, two small juveniles (7.4 and 9.6 mm ML) were found on a rocky area in May (15°40´N, 96°29´W) and one big juvenile (30 mm ML) was captured in a coral reef in December (15°44´N, 96°07´W). The geographic distribution of O. bimaculatus has been reported from California, USA to La Paz B.C.S (Mexico). This study provides new information on the abundance, distribution and size structure of early-stages of O. bimaculatus, redefining the geographic range of this species in the Tropical Eastern Central Pacific.

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There is practically no information on the biology of Lolliguncula (Loliolopsis) diomedeae. We analyzed specimens caught in four shrimp fishing trips in the Gulf of Tehuantepec in 1999-2001, 2004 and 2006.Sexual maturity and gonadosomatic index (GSI) were used as indicators of reproductive activity. A total of 1 200 individuals were captured, 89% female. Females ranged from 35 to 97mm in mantle length (LDM),with a mode at 80mm and weights 2 to 30,9g; males 20,7 to 65mm LDM with a mode at 35-40mm and weights from 0,4 to 12g. Differences in the LDM and the PT between males and females were significant (KS, p<0,05). The sex ratio was 8:1 H:M (p <0,05). The weight-length relationship type is potential for both sexes, with a negative allometric growth.83% of mature females had high IGS values, in contrast to less than 20% of mature males. The size at first maturity (L50) indicates that males (42,7mm LDM) mature when shorter than females (74,5mm LDM). Maturity, IGS and oceanographic features of the Gulf of Tehuantepec indicate that L. diomedeae spawn there.