The embryonic phase and its implication in the hatchling size and condition of Atlantic bobtail squid Sepiola atlantica

Abstract

Early life stages of cephalopods are somewhat complex due to the life history strategy or species specificity of generalized ontogenetic patterns and processes. This work aimed to determine the time length of embryonic development at different temperatures, and if the egg size is a determinant of hatchling size in Sepiola atlantica d 0 Orbigny, 1839-1842. Successful hatching occurred in 98.5-100% of the eggs for each female. As seen in other coleoid cephalopods, temperature determines the amount of time for embryonic development in S. atlantica, and the obtained data were very similar to other coleoid cephalopods. Developmental times for temperatures at 13 ± 0.4°C, 18 ± 0.3°C and 16.4 ± 1.1°C were 61.8 ± 3.8, 22.6 ± 1.7 and 40.1 ± 4.8 days. The duration of embryonic development and hatchling mantle length was not strictly related. The egg volume was positively related to hatchling mantle length. Our results provide new records on the duration of embryogenesis and other information on reproductive patterns in this species. Some hatching and post-hatching behaviour are shown and discussed.

Seasonal abundance of the Atlantic bobtail squidSepiola atlanticain Galician waters (NE Atlantic)

“…Rodrigues et al 2009, Rodrigues et al 2010Jones & Richardson 2010). Moreover, the size of the smallest individuals of S. atlantica collected in Areamilla coincides with hatchling size observed by Rodrigues et al (2011).…”

Reproduction of the Atlantic bobtail squid Sepiola atlantica (Cephalopoda: Sepiolidae) in northwest Spain

“…These peaks match the maturity index peaks (MGSI and FGSI) found in the present study. Because the length of S. atlantica embryonic development is positively correlated with water temperature (Rodrigues et al 2011b), embryos could grow quickly (±23 days at 18°C) and hatch in the same season they were spawned, which would explain the correspondence between the peak of juvenile abundance (Rodrigues et al 2011c) and the maturity index peak found here.…”

“…In a study on spawning strategy, Rodrigues et al (2011a) found trade-offs between female ML and egg size and mass in S. atlantica; the present results are in agreement only with the relationship between ML and egg mass. Our analyses of the relationships between female ML and fecundity, female ML and the coefficient of variation of ripe oocyte mass, and female ML and egg mass suggest that larger females do not produce larger numbers of progeny, but larger females could contribute to the next generation with higher-quality hatchlings because of increased egg and hatchling size (see Rodrigues et al 2011b). Larger hatchlings are suggested to have better survival capabilities when compared with smaller hatchlings (Steer et al 2003).…”

Life strategies of cephalopod paralarvae in a coastal upwelling system (NW Iberian Peninsula): insights from zooplankton community and spatio‐temporal analyses

“…Given that the embryonic development lasts for 40-47 days on average (Villanueva et al, 2003), two peaks of hatchlings are expected around March and August. Regarding sepiolids, spawning occurs between March and July (Rodrigues et al, 2011a) with an early development lasting for around 62-23 days at 13-18°C (Rodrigues et al, 2011b) and hatching occurring between May and September (Rodrigues et al, 2012). In contrast, O. vulgaris has an extended embryonic development of up to 4 months (Mangold and Boletzky, 1973).…”