The Common Occurrence of Oegopsid Squid Eggs in Near - Surface Oceanic Waters

A variety of egg types removed from near-surface plankton tows off Hawaii developed into young squids. Previously, the eggs of pelagic, oceanic squids were virtually unknown. Over 90% of these near-surface plankton tows taken with a l-m net contained squid eggs. About 90% of the eggs were collected in the upper 100m with most of these coming from the mixed layer. The eggs were separate rather than in masses. Two egg types have been identified. One belongs to the Enoploteuthinae, which are thought to spawn individual eggs. The other belongs to the Brachioteuthidae, whose spawning mode is unknown. Most squids are thought to deposit eggs in masses. Estimates, based on the abundance of the captured eggs, indicate that the chances of sampling an intact egg mass with a plankton net are small. Members of the Oegopsida are predominantly oceanic species. Most of these squids possess nidamental glands and, therefore, are thought to produce egg masses. On several occasions oegopsid squids belonging to the Ommastrephidae have spawned in captivity (Hamabe 1961, 1963; Boletzky et al. 1973; O'Dor et al. 1982). The eggs were generally spawned in large masses (up to 100,000 eggs). Very few records exist of naturally spawned eggs or egg masses from oceanic cephalopods. Most of the early reports (d'Orbigny and Ferussac 1839; Collingwood 1873; Grenacher 1874; Naef 1923 [Oegopsid X]; Sanzo 1929) described oegopsid egg masses of very similar appearance: large, gelatinous, cylindrical masses generally 60-90 em long by 10-20cm in diameter, containing rows of eggs which encircled the mass in a helix near its periphery. Sanzo (1929) attributed this type of egg mass to the large epipelagic squid Thysanoteuthis rhombus after raising the eggs to hatching and comparing the hatchlings to identified larvae taken from the plankton. In more recent years, this type ofegg mass has been observed at localities throughout much of the tropical and temperate oceans of the world (Clarke 1966; Nesis 1975; Misaki and Okutani 1976; Suzuki et al. 1979; pers . obs.) . Berrill (1966) published a beautiful color photograph ofone of these egg masses which was misidentified as the pelagic tunicate Pyrosoma. 359 THE SPAWNED EGGS of marine animals can be useful guides for investigating life-history strategies and adult population parameters, and they can provide a source of young, undamaged animals for experimental purposes (Price 1974; Stearns 1976; Stauffer and Picquelle 1980). The eggs of pelagic , oceanic squids, however , are virtually unkown, even though most species have larvae in nearsurface waters. Squids belong to the cephalopod order Teuthoidea, which is divided into two suborders: Myopsida and Oegopsida. Members of the Myopsida (that is, the families Loliginidae and Pickfordiateuthidae) are almost exclusively neritic in habitat. Members of the most common myopsid genus, Loligo, deposit their eggs in many small masses on the shallow sea floor (McGowan 1954; Mangold-Wirz 1963; Waller and Wicklund 1968). During spawning, the eggs are coated with a layer of jelly from the oviducal glands which is, in turn, covered by large quantities ofjelly from the nidamental glands (Jecklin 1934). 1 This material is based on research supported in part by the National Science Foundation under Grant OCE 82-07754. Manuscript accepted May 1985. 2 Department of Oceanography, University of Hawai i, 1000Pope Rd. , Honolulu , HI 96822. 3 Laboratorie Arago , F-66650 Banyuls-sur-Mer, France .