Incubation of European Squid (Loligo vulgaris Lamarck, 1798) eggs at different salinities

Abstract

Loligo vulgaris is a commercially important squid throughout the Mediterranean region and is a candidate species in biomedical and aquaculture research. Some loligo species (L. opalescens, L. forbesi, Sepiteuthis lessoniana) have now been cultured through some successive generations in closed, recirculating seawater systems. The e¡ects of salinity on hatching European Squid (L. vulgaris Lamarck,1798) eggs were investigated during November 2004. The egg capsules were incubated directly in salinity of 32, 34, 36, 38, 40, 42 and 37 g L À1 (control group) at 19.8 1C (SD 1.2 1C), and a photoperiodicity of 12 h light:12 h dark for 16^23 days before hatching. In all treatments, the eggs were developed and hatched normally after 16^22 days at 32 g L À1 , 17^22 days at 34, 18^21 days at 42 g L À1 ,18^22 days at 36 and 40 g L À 1 ,19^22 days at 37 g L À1 and 19^23 h at 38 g L À1 . In the experiments, the highest hatching rate and hatching success (HS) of the eggs were obtained at 38 g L À1 (hatching rate: 100% (SD 0%) and HS: 96.7% (SD 3.5%)) and the lowest hatching rate at 42 g L À1 (hatching rate: 3% (SD 6%) and HS: 0%). Dorsal mantle lengths (DML) of new hatchlings ranged from 2.08 to 2.80 mm. The present study showed that salinity a¡ects the hatching rate and HS of eggs and ¢rst hatching time and DML of paralarvae in L. vulgaris. The squid eggs at stage 11 (I) can tolerate 5 g L À1 reduction and 3 g L À1 increase in salinity.

Abiotic influences on embryo growth: statoliths as experimental tools in the squid early life history

“…Means with the same letters are not significantly different b groups of embryos and may affect in some degree the results observed. Incubating loliginid eggs under constant salinities during full embryonic development period indicates that there are optimal salinities that maximise hatching success, e.g., Loligo vulgaris, 34-42& (D'Aniello et al 1989); 34-38& (Sen 2005); Loligo gahi, 26.4-32.8 & (Cinti et al 2004) and Sepioteuthis lessoniana, 21.8-36.6& (Nabhitabhata et al 2001). Coastal waters in subtropical and tropical coastal reefs are frequently exposed to heavy seasonal rain that may reduce salinity for short periods of time.…”

“…Statoliths are a very useful tool to study squid age and growth (Jackson 1994), and we know that a record of temperature effects are present in the statoliths of embryos and hatchlings (e.g., Durholtz and Lipinski 2000;Villanueva 2000a, b). However, the influence of other abiotic factors on embryonic development and hatching success in cephalopods, such as photoperiod (Paulij et al 1990a(Paulij et al , 1991, light intensity (Ikeda et al 2004), and salinity (Palmegiano and D'Apote 1983;D'Aniello et al 1989;Paulij et al 1990b;Nabhitabhata et al 2001;Cinti et al 2004;Sen 2005) is less understood. Identifying how the effect of these abiotic factors is recorded in the statolith structure will provide a useful tool when studying wild populations (Chung and Lu 2005).…”

Effects of Cadmium (CdCl2) on development and hatching of eggs in European squid (Loligo vulgaris Lamarck, 1798) (Cephalopoda: Loliginidae)

“…As reported by Sen (2005a), total hatching and hatching success rates were calculated as 98.9-98.8% and 84-86%, respectively, and the hatching period of the paralarvae occurred between the days 5-7 at 18± 1°C. Also, we calculated total hatching and hatching successes as 98.2±1.6% and 94±2.3%, respectively, and the hatching period of the paralarvae lasted 4 days at 19.8±1.6°C (Sen 2005b).…”

“…Since 1979, rearing experiments were carried out on L. vulgaris, because of its great scientific and economical importance (Boletzky 1979;Turk et al 1986;Worms 1983). The egg capsules of L. vulgaris are laid on the underside of rocky overhangs, on branched sessile organisms (Boletzky 1998) or on fishing lines (Sen 2004(Sen , 2005aVillanueva et al 2003) and hang down in the water. Hence, the egg capsules stand wherever laid and expose to every kind of heavy metals from not only the water but also the sediment environments.…”

Estrutura e funcionamento dos espermatóforos de Doryteuthis plei (Mollusca: Cephalopoda) e reavaliação da reação espermatofórica dos cefalópodes

“…Ikeda et al 2004a), salinity (e.g. Sen 2005), ionic composition of seawater on embryo growth and viability (e.g. D 'Aniello et al 1989); and rates and causes of embryonic abnormalities (e.g.…”