Antarctic Flying Squid

Todarodes filippovae Adam, 1975

DIAGNOSIS.—Medial manus sucker rings with 7–13 long, pointed teeth, diameters of largest suckers 2.7%–4.5% ML; manus with 12–14 quadriserial sucker rows.

ORIGINAL DESCRIPTION.—Adam, 1975:3.

TYPE LOCALITY.—Southern Indian Ocean, 35°S-38°S, 66°E-77°E.

DEPOSITION OF TYPES.—Holotype: Institut Royal des Sciences Naturelles de Belgique, Brussels, female, 320 mm ML, 35°S-38°S, 66°E-77°E, Dec 1967.

Paratypes: Institut Royal des Sciences Naturelles de Belgique, Brussels, 2 males, 210 mm ML, 213 mm ML, and 3 females, 210–220 mm ML, collected with holotype; 3 females, 210–280 mm ML, 35°40′S, 66°10′E, 22 Dec 1967; 2 males, 185 mm ML, 220 mm ML, and 2 females, 182 mm ML, 190 mm ML, 38° 15′S, 77° 10′E, 28 Dec 1967; 2 males, 220 mm ML, 225 mm ML, 40°S, 49°E, 6 Apr 1970.

GEOGRAPHICAL DISTRIBUTION.—Continental slope and oceanic waters of the Southern Ocean and adjacent waters, apparently abundant in and adjacent to subtropical convergence zone.

Todarodes filippovae Adam, 1975

The Southern Ocean arrow squid, T. filippovae, was originally described from specimens from the southern Indian Ocean. In subsequent studies in southern subtropical and subantarctic waters, Russian workers have failed to recognize the validity of this species and have referred all Todarodes from these waters to T. angolensis Adam, 1962 (Zuev et al., 1976; Nesis, 1979a, 1979b, 1979c, 1987; Roeleveld, 1989). Thus, the literature remains confused as to the distribution of these species. Okutani (1980) considers T. filippovae to have a circumsubantarctic distribution, and its distribution overlaps that of T. angolensis off southwestern Africa (Roeleveld, 1989).

Todarodes filippovae has previously been reported from eastern Tasmanian waters by JAMARC (1978), and it is likely that the adult Todarodes reported by Nesis (1979c) from south of Tasmania and eastward from New Zealand also are referable to this species (Roeleveld, 1989; K.N. Nesis, pers. comm., 1991). Todarodes angolensis is rare in collections from the western Tasman Sea.

Nesis (1979b) considered “T. angolensis” to be restricted to waters south of 45°S in the southern Tasman Sea. The results of recent studies have extended the distribution of T. filippovae further to the north in summer, and surface driftnet surveys also have shown that although adults are caught near the bottom in slope waters, they apparently migrate throughout the water column and are caught at the surface at night.

Three juveniles of 40 mm ML, 66 mm ML, and 80 mm ML were caught at the surface at night using scoop nets in the extreme west of the Tasman Sea off eastern Tasmania (38°28′S, 154°26′E, and 41°44′S, 153°24E; surface temperatures 19.5° C and 15.5° C) in late December 1981. None of the plankton collections from the Tasman Sea or eastern Australian coast reported by Dunning (1988c) contain larvae positively identified as this species.

Morphological characters separating the larvae of Todarodes spp. from those of Nototodarus gouldi (McCoy, 1888), which have been commonly reported from these waters, remain unclear. A single larva, 8 mm ML, was recorded from south of Tasmania (sea surface temperature 10.5° C) by Nesis (1979a, pers. comm., 1981) as T. angolensis and may be referable to the more abundant T. filippovae.

Off the eastern Australian coast, adult T. filippovae have been caught in midwater and demersal trawls and on jigs between 33°08′S and 47°42′S (the most southerly station sampled) where sea surface temperatures ranged from less than 11.5° C to 24.7° C. In the summers of 1981–1982 and 1982–1983 in the central Tasman Sea, adults were caught in surface waters (0–50 m) between 32°45′S and 45°45′S (the most southerly station sampled), with corresponding sea surface temperatures of 20.1° C and 14.2° C. Temperatures at 50 m at these stations ranged from 11.8° C to 18.0° C (Dunning, 1988c).

On the slope and deeper shelf off the west coast of New Zealand, adult and juvenile T. filippovae have been caught in demersal and midwater trawls, jigs, and in surface driftnets between 36°S and 50°26′S (on the northern Aucklands Shelf) (Kawakami, 1976; Uozumi et al., 1987). Sea surface temperatures where this species has been caught vary from 8.5° C to 19.7° C.

Figure 3 shows the distribution of adults and juveniles in the region.

Variation in abundance with respect to latitude in mean numbers of T. filippovae from jig catches in the Tasman Sea (December 1981-February 1982) is shown in Figure 5. Numbers increased toward the southernmost stations sampled (south of 44°S, surface temperatures less than 14° C). No specimens were caught in surface waters with temperatures greater than 20° C (Dunning, 1988c).

Todarodes filippovae could be primarily associated with the Subtropical Convergence Zone in the Southwest Pacific, with a similar geographical distribution to the mesopelagic cranchiid Teuthowenia pellucida (Voss, 1985), but definition of the southern boundary of its distribution awaits further study.