Description: The seven star flying squid, Martialia hyadesi, is a Southern Ocean ommastrephid with an oceanic distribution that extends to the edge of the shelves and slopes of continents and islands. Its range is circumpolar and it is generally associated with the Antarctic Polar Frontal Zone. It has been caught in commercial quantities in the Atlantic sector but is only recorded in smaller numbers from the Indian Ocean and Pacific sectors in scientific samples, the gut contents of predators and in mass strandings on island shores. It has only occasionally been found in commercial catches outside the Atlantic sector. In the northern part of its range in the South Atlantic, commercial catches are highly variable and apparently linked to large-scale oceanographic variability. Martialia hyadesi appears to concentrate in frontal areas where characteristics of the bathymetry generate meso-scale oceanographic features. Such concentrations have been observed at shelf breaks and in the deep ocean near a submarine ridge. Predator data confirm the circumpolar distribution of the species and its relationship with the APFZ. Grey-headed albatrosses appear to forage for M. hyadesi in the region of meso-scale oceanographic features associated with the bathymetry of submarine ridges and the shelves of oceanic islands. In the medium future, improved understanding of oceanographic variability of the Southern Ocean may provide the basis for long term forcecasting in a fishery for the species. In the nearer future, improved knowledge of the behaviour of the species in relation to meso-scale oceanography may provide the basis for short-term forecasting of the location of shoals based on remotely sensed images of surface oceanography. The life cycle of M. hyadesi is poorly understood and, in view of increased commercial interest in the species in recent years, and its conservation value in the CCAMLR area, there is a need for more information on the location of spawning and feeding grounds and seasonal migrations.

Description: Mastigophora brevipinnis Owen, 1856, is a ‘fossil teuthid’ presently considered to be a member of the coleoid cephalopod Suborder Loligosepiina Jeletzky, which in turn has been placed by various authors in or near the Vampyromorpha Grimpe. Recent morphological and biochemical analyses indicate that vampyromorphs are more closely related to the Octopoda than to the Decapodiformes. Fossils of Mastigophora from the Oxford Clay (Jurassic: Callovian) show soft-tissue preservation and evidence of arm crown specialization. Some of these fossils have up to eight short, thick arms with circular sucker-like structures and filiform distal extensions, plus what appear to be the bases of two thinner ventrolateral arms. The latter lack proximal suckers and curve medially to insert into the arm crown, similar to the tentacles that are the modified ventrolateral arms of living squids and cuttlefishes. This suggests that the thinner structures were decapod-like tentacles. If Mastigophora had tentacles homologous with those of modern decapods, then it was a decapod, because this synapomorphy defines the Decapodiformes. This indication of decapod affinities for Mastigophora brings into question the relationships of the other ‘fossil teuthids’. The inferred relationship of the Loligosepiina, including Mastigophora, with the Vampyromorpha, based largely on similarities of gladius morphology with that of living Vampyroteuthis, may reflect shared plesiomorphic characters.

Description: Some 290 species of squids comprise the order Teuthida that belongs to the molluscan Class Cephalopoda. Of these, about 30-40 squid species have substantial commercial importance around the world. Squid fisheries make a rather small contribution to world landings from capture fisheries relative to that of fish, but the proportion has increased steadily over the last decade, with some signs of recent leveling off. The present overview describes all substantial squid fisheries around the globe. The main ecological and biological features of exploited stocks, and key aspects of fisheries management are presented for each commercial species of squid worldwide. The history and fishing methods used in squid fisheries are also described. Special attention has been paid to interactions between squid fisheries and marine ecosystems including the effects of fishing gear, the role of squid in ecosystem change induced by overfishing on groundfish, and ecosystem-based fishery management.

Description: The nekton community was sampled by a Rectangular Midwater Trawl (RMT 25) over the upper 1000 m of the Scotia Sea dunng January 1991. A total of 81 nekton and micronekton species were collected from 2 sites, one in the oceanlc western Scotia Sea (Stn 1) and the other on the northwestern slope of the South Georgia shelf (Stn 2). Species composition, abundance, biomass and day/night vertical distribution were investigated. Crustaceans were the most important group in terms of species numbers (28 species) followed by mesopelagic fish (24), molluscs (15) and coelenterates (11). Species diversity increased with depth and was higher at Stn 2 (76 species) than at Stn 1 (62 specles). Biomass in the upper 1000 m was considerably higher at Stn 1 (94.6 g wet wt m-2 during daytime, 87 g wet wt m-2 during night) than at Stn 2 (10.2 and 23.7 g wet wt m-2, respectively), mostly due to dense concentrations of the tunicate Salpa thompsoni (41.6 g wet wt m-2 during night). The other main contributors to the high biomass at Stn 1 were coelenterates (28.3 g wet wt m-2 during night) and mesopelagic fish (4.9 g wet wt m-2 during night). Euphausiids (Euphausia triacantha and E. superba) accounted for 1.5 g wet wt m-2 at Stn 2 during night, with E. triacantha the more important of the two (1.4 g wet wt m-2). Except for Bathylagus antarcticus all common mesopelagic fishes showed a marked diurnal vertical migration (i.e. Electrona antarctica, Gymnoscopelus brauen, Krefftichthys anderssoni, Protomyctophum bolini). During daylight they stayed in the core of the Circumpolar Deep Water (CDW, 400 to 800 m) and at night they were mainly distnbuted in the Antarctic Surface Water (ASW, 0 to 400 m). Other species with pronounced vertical migration were the hydromedusa Calycopsis borchgrevinki, the squid Brachioteuthis ?picta, and the euphausiid Euphausia triacantha. The scyphomedusae Atolla wyvillei and Periphylla periphylla and the crustaceans Cyphocaris richardi, Gigantocypris mulleri and Pasiphaea scotiae did not appear to migrate and remained concentrated in the CDW. Spatial variability was analysed by multivariate data analyses (clustering techniques) and related to hydrography. Four main groups, characterised by different nekton communities, were derived: (1) a lower mesopelagic nekton community from the deeper layers of the CDW, apparent at both stations, (2) an upper mesopelagic nekton community from the core of the CDW, apparent at both stations, (3) an epipelagic nekton community from the ASW over the South Georgia slope (Stn 2) and finally (4) an epipelagic nekton community from the ASW of the oceanic Scotia Sea (Stn 1). The performance of the midwater trawl is discussed as it has a substantial impact on the catchability of the nekton. The presented data provide new information on the structure and spatial variability of Antarchc nekton communities and emphasise the geographical and vertical discontinuities between communities.

Description: In the Atlantic sector of the Southern Ocean, data from vertebrate predators and commercial fisheries suggests that the distribution of the ommast rephid squid Martialia hyadesi is related to the Antarctic Polar Frontal Zone, but it spreads further to the north in some years (Rodhouse, in press). A mass stranding of M. hyadesi occurred on Macquarie Island in 1971 (O'Sullivan et al. 1983) suggesting that its distribution is c ircumpolar (Rodhouse and Yeatman 1990). However, apart from a single beak collected from the s tomach of a wandering albatross at Mar ion Island (Imber and Berruti 1981) its presence has not, until now, been confirmed in the Indian Ocean sector and in particular it is not included in the list of cephalopods from the Kerguelenian Province (Lu and Mangold 1978). M. hyadesi is a major prey item of the grey-headed albatross, Diomedea chrysostoma, and the southern elephant seal, Mirounoa leonina, at South Georgia (Rodhouse et al. 1990; Rodhouse et al., unpublished data) and is present in the diet o f several other predators in the Scotia Sea area including the wandering albatross, Diomedea exulans (Rodhouse et al. 1987) and the giant petrels, Macronectes halli and M. gioanteus (Hunter 1983). It occasionally occurs as a significant by-catch in the lllex argentinus fishery on the Pa tagonian Shelf and has been taken during commercial squid jigging trials in the Scotia Sea at the Antarctic Polar Frontal Zone (Rodhouse, in press). It appears to have potential for commercial exploitation in the sub-Antarctic waters of the Atlantic sector of the Southern Ocean (Rodhouse 1990). In view of the ecological importance of M. hyadesi to Antarctic predators, and the likelihood that it will be commercially exploited in the future, it is important to thoroughly establish its geographical range, and in particular to confirm its circumpolar distribution.

Description: Todarodes filippovae Adam 1975 is a large oceanic ommastrephid squid with a pelagic distribution. It is closely related to T. angolensis but allozyme data have shown that the two species are separated by about the same genetic distance as other ommastrephid congenerics. T. jilippovae itself may comprise more than one species. It is reported to be widespread in the Southern Ocean from sub-Antarctic waters to north of the subtropical Front, but there are gaps in its known distribution which cast doubt on the conspecificity of the different populations. Squid identified as T. filippovae inhabit the open ocean up to the continental slope and they appear not to extend into shelf waters. Distribution of the various populations seems to be Jinked to the high velocity regions of the Antarctic Circumpolar Current, Falkland Current, Benguela Current and East Australia Current and these are probably important for transport of planktonic eggs and paralarvae and for the productive mesoscale features that these highly dynamic systems provide for adult feeding. Beaks attributed to T. filippovae have been found in the gut contents of sperm whales (Physeter catodon), southern elephant seals (Mirounga leonina), fish (Merluccius australis polylepis) and possibly by albatrosses (Diomedea melanophrys); however, there are insufficient data to estimate the annual consumption by known predator species. The juveniles feed on crustaceans, whereas the adults feed primarily on fishes and other cephalopods. In common with many other squid, they probably occupy a broad trophic niche. Knowledge of the life cycle is very incomplete. Spawning occurs in the Tasman Sea and off South Africa and probably takes place in the austral autumn and winter. The life span may be up to two years. Fishery potential has not been established, but in the Tasman Sea commercially viable catch rates have been reported. Effective exploitation and rational management of T. filippovae, or filippovae species/subspecies complex, requires research on species identification and stock structure, a full understanding of the life cycle of the different populations, knowledge of the relations between ocean currents, mesoscale oceanographic processes and biology, and a better understanding of role in the diet of higher predators.

Description: A comprehensive study of octopodids in the Weddell Sea was conducted during cruise ANT XIII/3 of RV "Polarstern". The study yielded eight species of incirrate octopodids, three of which were undescribed. There appeared to be no differences in octopodid species assemblage in the two sampling areas (Kapp Norvegia and south of Drescher Inlet), supporting the theory that there is a single macrobenthic assemblage on the eastern shelf of the Weddell Sea. Six of the octopodid species belonged to the genus Pareledone, illustrating the extensive radiation of this endemic genus within the Southern Ocean. The fragmented nature of suitable habitats and disturbance caused by glaciation cycles are proposed as mechanisms for this radiation. Comparative data illustrate that both the number of octopodid species present and their abundance are greater at higher latitudes than close to the Antarctic Polar Frontal Zone.