Effects of temperature on embryonic development of the Humboldt squid Dosidicus gigas

Abstract

Little is known about embryonic development of oceanic squids, yet such information is critical to a meaningful understanding of these ecologically and economically important species. Eggs of the Humboldt squid Dosidicus gigas were artificially fertilized and incubated at temperatures found throughout this species' range (5 to 30C). Successful development through hatching was observed only between 15 and 25C, and the rate of development increased with increasing temperature. Previous work reported a D. gigas egg mass at the pycnocline in the Gulf of California, suggesting that successful embryonic development can occur only in those areas of the eastern Pacific where temperature at the pycnocline is between 15 and 25C. Analysis of available oceanographic data revealed a vast area relatively close to the California coast that is seasonally suitable for development of D. gigas embryos. Spawning offshore in this region may thus be an important factor supporting the D. gigas populations that invaded coastal waters of the Pacific Northwest after 2005.