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Captive spawned egg mass of Todarodes pacificus (diameter: 80 cm; Puneeta et al. 2015).  

Captive spawned egg mass of Todarodes pacificus (diameter: 80 cm; Puneeta et al. 2015).  

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Article
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Ommastrephid squids have a pelagic lifestyle, with reproductive behavior that is characterized by the extrusion of fragile, neutrally buoyant egg masses, the release of paralarvae into the surface plankton, and the use of large-scale current patterns for larval transport, leading to the assisted migration of populations. Although the exact process...

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... where spermatophores are stored inside the mantle cavity, mechanical activity mixes the eggs from the oviducts, the gelling agents from the nidamental and oviducal glands, and the broken spermatophores with water to form the substance of the egg mass. These secretions accumulate and swell gradually in front of the female to form a large egg mass (Fig. 2). OÕDor et al. (1982a) describes the process as being ''similar to blowing up bubble gum.'' The mobility of females is limited during spawning because the funnel, which is usually used for loco- motion (jet propulsion), is used to pump the egg mass constit- uents. Consequently, females might sink through the epipelagic zone during the ...

Citations

... However, direct observations of embryonic development within spawned egg masses have been limited and partial because ommastrephid egg masses are tenuous, transparent, and short-lived (Vijai 2016); and hence have rarely been reported from the wild (Naef 1928, Laptikhovsky & Murzov 1990, O'Shea et al. 2004, Staaf et al. 2008, Birk et al. 2016). The only detailed study of an ommastrephid egg mass in the wild is the classic work of Naef (1928) illustrating the embryonic development of the southern shortfin squid, Illex coindetii (Vérany, 1839). ...
... Sin embargo, las observaciones directas del desarrollo embrionario dentro de las masas de huevos desovados han sido limitadas y parciales, debido a que esas masas son tenues, transparentes y de corta vida (Vijai 2016) y raras veces se han reportado en el medio silvestre (Naef 1928, Laptikhovsky y Murzov 1990, O'Shea et al. 2004, Staaf et al. 2008, Birk et al. 2016. El único estudio detallado de una masa de huevos de ommastréfidos en el medio silvestre es el clásico trabajo de Naef (1928) que ilustra el desarrollo embrionario del calamar de aleta corta del sur Illex coindetii (Vérany, 1839). ...
... Most of the eggs in the tank were unfertilized. Fertilization in the ommastrephids takes place while spawning (Hamabe 1962, O'Dor & Dawe 2013, Vijai 2016, and the low fertilization rate in the present study might have been due to the anomalous spawning conditions. In the fertilized eggs, normal embryonic development was observed from the 4th cleavage phase (16 cells, Stage 7) until hatching (Stage 30, Fig. 1). ...
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Egg masses were spawned by a jumbo squid Dosidicus gigas (mantle length 37.5 cm) held in a tank (500 L) on board the R/V Kaiyo Maru during a joint Japan-Peru cruise in Peruvian waters during December 2011– February 2012. Part of an egg mass was collected and incubated in an aquarium (10 L) maintained at 20 °C. The eggs had a unique jelly envelope surrounding the chorion. The diameter of the jelly envelope was more than twice the diameter of chorion. It remained clearly visible until the embryos reached developmental stage 18. Most of the eggs were fertilized and hatched (Stage 30) 6.5 days after spawning at 20 °C.
... The egg masses of these squid can range in size from individual eggs of several millimetres in diameter, as is the case for some enoploteuthids (Young et al. 1992), to large, spherical masses up to almost two metres in diameter, containing many thousands of eggs (O'Shea et al. 2004;Staaf et al. 2008). Being neutrally buoyant the egg mass finds itself transported passively in currents until the individual eggs within start to hatch and the hatchlings swim to the sea surface (Bower and Sakurai 1996;Boyle and Rodhouse 2005;Nishikawa et al. 2014;Vijai 2016). Oviducal jelly is known to be necessary for chorion expansion and survival (Ikeda et al. 1993;Villanueva et al. 2011). ...
Article
A total of 27 large, gelatinous spherical masses observed in coastal Norwegian waters from Nordland to Aust-Agder Counties in Norway, and off Lysekil in Sweden, Muljica Island in Croatia, Gulf of Naples in Italy, Reqqa Point in Malta, and Saint Mandrier in France, during the months of April to September 2001 to 2017, are reported. Individual spheres measured 0.3 - 2 m in diameter, averaging one metre (n = 24, +/− 0.53 m), with all but four sighted in suspension in the water column between 0.5 and 52 m depth, in water temperatures ranging between 10 - 21°C. About half of all spheres contained a yellow-red streak through their gelatinous core. Tissue samples were not obtained. We attribute these gelatinous spheres to the egg masses of squid (Cephalopoda, Oegopsida), and most likely to the ommastrephid Todarodes sagittatus, given similarities with egg masses of T. pacificus.
... It is unkown if a similar consort behaviour occur in Illicinae. (Vijai, 2016). During spawning, fertilized eggs are embedbed by mucous layers released by oviducal and nidamental glands ( Fig. 6C-D). ...
Thesis
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Flying squids develop all its life cycle in the water column, as planktonic paralarvae and then as nektonic subadults and adults. In this Ph. D. Thesis, light was shed over several poorly understood aspects of the ontogeny and phylogeny of the Family Ommastrephidae. The mechanism of sperm migration from spermatangia to the female seminal receptacles was studied. Spermatozoa are able to actively migrate between both structures. The morphology of the hatchling of three Mediterranean ommastrephid species was studied based on embryos obtained by in vitro fertilization and a dichotomous key was develop to identify NE Atlantic species. The first feeding diet of paralarvae was assessed through laser-capture microdissection and DNA metabarcoding. The results indicate an ontogenetic shift from detritivorism to active predation. Molecular data indicate that the taxonomic name Ommastrephes bartramii actually hides four biological species. These advances in scientific knowledge have potential applications for a better understanding of the ecology, physiology, biodiversity and fishery science that will foster a deeper understanding of flying squids.
... To understand the vertical distribution of floating egg masses in the sea, we must understand the physical properties of the egg mass and combine this information with distribution surveys [33,47]. Considering the lack of available direct data on the distribution of T. pacificus egg masses in the wild [48], data on the physical properties from laboratory studies are the only available source from which to derive assumptions on their vertical distribution. Comparison of this data to that inferred from the spawning ground in the context of the "reproductive hypothesis" of T. pacificus could provide important insights about their distribution. ...
Article
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The Japanese flying squid, Todarodes pacificus, is thought to spawn neutrally buoyant egg masses that retain a specific location in the water column by floating at the interface between water layers of slightly different densities. It is important to understand the physical process that determines the vertical distribution of the egg masses to predict their horizontal drift in relation to embryo survival and subsequent recruitment. Here, mesocosm experiments were conducted in a 300 m3 tank by creating a thermally stratified (17–22°C) water column to obtain egg masses. A cage net methodology was developed to sustain egg masses for detailed observation. We measured the density of the egg masses of T. pacificus, and used this information to infer the vertical distribution patterns of the egg masses at the spawning grounds (Tsushima Strait, Japan). When measured separately, the density of the outer jelly of each egg mass was 2.7 σ units higher than that of the surrounding water. The outer jelly and the specific gravity of embedded individual eggs (~1.10) cause the egg masses to have very slight negative buoyancy relative to the water in which they are formed. Analysis of the vertical profile of the spawning ground showed that water density (σθ) increased sharply at ~30 m depth; thus, egg masses might settle above the pycnocline layer. In conclusion, we suggest that T. pacificus egg masses might retain their location in the water column by floating at the interface between water layers of slightly different densities, which happen to be above the pycnocline layer (actual depth varies seasonally/annually) in the Tsushima Strait between Korea and Japan.
Article
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In total, 90 gelatinous spheres, averaging one meter in diameter, have been recorded from ~1985 to 2019 from the NE Atlantic Ocean, including the Mediterranean Sea, using citizen science. More than 50% had a dark streak through center. They were recorded from the surface to ~60-70 m depth, mainly neutrally buoyant, in temperatures between 8-24⁰C. Lack of tissue samples has until now, prohibited confirmation of species. However, in 2019 scuba divers secured four tissue samples from the Norwegian coast. In the present study, DNA analysis using COI confirms species identity as the ommastrephid broadtail shortfin squid Illex coindetii (Vérany, 1839); these are the first confirmed records from the wild. Squid embryos at different stages were found in different egg masses: 1) recently fertilized eggs (stage ~3), 2) organogenesis (stages ~17-19 and ~23), and 3) developed embryo (stage ~30). Without tissue samples from each and every record for DNA corroboration we cannot be certain that all spherical egg masses are conspecific, or that the remaining 86 observed spheres belong to Illex coindetii. However, due to similar morphology and size of these spheres, relative to the four spheres with DNA analysis, we suspect that many of them were made by I. coindetii.