Oocyte development, packing in the ovary, and spawning pattern of squid Lolliguncula panamensis in the Mexican South Pacific

Abstract

Squid Lolliguncula panamensis (Hoyle, 1904) is of commercial and ecological importance in the Gulf of Tehuantepec (southeastern Mexico). This study examines the mode of oocyte development, packing in the ovary, and spawning pattern of this understudied species. L. panamensis presents a synchronous oocyte growth in batches, with multiple spawning, with the presence of post-ovulatory follicles and atretic follicles, including the constant presence of pre-vitellogenic and vitellogenic oocytes. The size frequencies of oocytes of ripe ovaries exhibit a pronounced morphological and size separation between the late yolk stage and mature oocytes, suggesting that the oocytes pass through this size range very fast. These oocytes adopt a geometrical shape that makes their packing efficient for spawning. One three-dimensional packing of vitellogenic oocytes (scutoid type) in the ovary was observed. The results of our study suggest that the spawning behavior of L. panamensis may constitute an opportunistic reproductive strategy in which individuals present multiple spawning over a brief period. We suggest that this strategy might be a response to complex regional oceanographic conditions of the Gulf of Tehuantepec.