It appears that squid statoliths cannot yet be regarded as accurate an ageing tool as fish otoliths. Statoliths from the same pair, prepared differently for viewing and counting increments, were compared. Increment counts do not imply age in days, because this was not validated. One statolith from each pair was examined by light microscopy (LM) after preparation following a new method. The other was viewed by Scanning Electron microscopy (SEM) with a modified etching solution. Shape of each statolith was similar when compared by multiple regression analysis (11 variables, n=53). There was a weak but significant difference between sexes (statoliths of females were slightly larger). All other differences were insignificant. Microscopic observation and increment counts of increments were successfully carried out for 37 pairs of statoliths. Significant differences between two independent counts were found for the LM method, but no significant differences were found between two independent SEM counts. Counts were significantly different when interpreted by both LM and SEM, probably because of poor resolution in the LM readings and over-resolution (growth layers prominent and numerous) in those read by SEM. Recommendations are made on how ageing studies, based on statoliths, should be structured and the results evaluated.

Fifteen samples of very low-grade mudstones from two widely separated sections in the Miers Bluff Formation on Hurd Peninsula yield an Rb-Sr errorchron (MSWD=8.9) corresponding to an age of 243 ± 8 Ma. This age is interpreted as representing effective homogenization, on a kilometres scale, during turbidite deposition and diagenesis in early Triassic times. The initial 87Sr/86Sr ratio 0.7085 ± 0.0003 represents a mature crustal source and is consistent with the re-working of material comparable to that eroded from the Chilean fore-arc accretionary complex. Four further samples, collected near to a zone of quartz-carbonate veins, lie to the right of the errorchron, with two samples having unusually low Sr contents. These samples fall on a 113 Ma reference line and indicate metasomatic disturbance in Cretaceous times. Metasomatism was probably related to hydrothermal alteration accompanying widespread silicification and quartz veining on western Hurd Peninsula. A mid-to late Cretaceous age for metasomatic disturbance agrees with field relations which indicate that the hydrothermal activity preceded or was coeval with the mid- to late Cretaceous period of volcanism on Livingston Island. Hence the hydrothermal rocks are not related to the Eocene Barnard Point pluton, as previously suggested.

The teuthoid fauna of the Prydz Bay region of the Southern Ocean (Indian Ocean sector) has been studied based on the material collected from 1981–1991 using a rectangular midwater trawl (RMT-8), pelagic trawl (IYGPT), and bottom trawl. Eight species of squid have been recognized: Brachioteuthis sp., Kondakovia longimana, Bathyteuthis abyssicola, Psychroteuthis glacialis, Alluroteuthis antarcticus, Mastigoteuthis psychrophila, Mesonychoteuthis hamiltoni and Galiteuthis glacialis. Size frequency distribution, geographical and vertical distributions of each species as well as diets of common species are analysed. There is no evidence of a diel vertical migration but ontogenetic descent appears to occur in P. glacialis and G. glacialis. Antarctic krill, Euphausia superba and the Antarctic silverfish, Pleuragramma antarcticum are important prey for most species with cannibalism occurring in P. glacialis, A. antarcticus and M. hamiltoni. Equations for calculating total weight from mantle length, and mantle length and total weight from upper and lower rostral length are provided for B. abyssicola, P. glacialis, A. antarcticus, M. psychrophila, and G. glacialis.

Spread-F is caused by the presence of ionospheric electron concentration irregularities of scale-size of order 5 km at F-region altitudes. Estimates of spread-F in the vicinity of the maximum plasma frequency of the Flayer (foF2) have been determined at 15 min intervals from ionograms recorded over a ten day period (1–10 May 1986) both at Marsh (62.2°S, 58.9°W), King George Island, and Faraday (65.2°S, 64.3°W), Argentine Islands. The interval, at low solar activity, includes periods of quiet and disturbed geomagnetic activity. Spread-F is observed on every night at both stations. It is more frequent, slightly more intense and starts earlier at Argentine Islands than at King George Island. On most nights, spread-F ceases about local sunrise at 120 km altitude at both stations. On the days of highest geomagnetic activity, the onset of spread-F is delayed compared with days of lower activity. Spread-F is usually most intense on the night(s) following largest geomagnetic activity level, as measured by the geomagnetic index, Kp. The growth rate of the plasma instability processes causing the ionospheric irregularities is inversely related to electron concentration (foF22), amongst other parameters. Thus the lower foF2 values over Argentine Islands are consistent with more spread-F being observed by the higher latitude observatory. However, no firm relationship between the absolute value of foF2, the horizontal gradient of foF2 between the two observatories, and the onset of spread-F, is found. Thus it has not been possible to determine uniquely the instability process responsible for the formation of the plasma irregularities.

Two specimens of Kondakovia longimana were recently obtained from the Indian Ocean sector of the Southern Ocean. One specimen, damaged but near the known maximum size, was found floating on the surface, and the other, a male subadult specimen, was captured by a pelagic trawl. Examination of the specimens, histological sections and analyses of tissue samples revealed that the muscular tissues of the tentacular stalks and the mantle contain a large amount of ammonium, more than 328 mM, a quantity that far exceeds that of Moroteuthis ingens (206.9 mM) and Moroteuthis robsoni (199.6 mM) from the South Tasman Rise. Catch data and published records suggest that the juveniles and subadults of K. longimana feed on krill in the epipelagic zone.

The relatively small numbers of pelagic cephalopods caught in the RMT-8 samples (0–300 m) in February/March 1983 in the Weddell Sea were dominated by early life stages of the cranchiid squid Galiteuthis glacialis. A total of 48 specimens were caught with dorsal mantle length (ML) ranging from 4–36 mm. They occurred with a mean density of 0.15 ind. × 1000 m−3 and were present in 38% of 33 RMT-8 samples. G. glacialis was the only cranchiid squid found in the Weddell Sea between 66° and 74°S. Its early life stages were concentrated in the layers below the summer thermocline (>50 m) and body sizes appeared to increase towards deeper water layers. For biochemical analyses, nine specimens of G. glacialis (ML 6–18 mm) were sampled in the eastern Weddell Sea between 185–520 m water depth in January/February 1985. Total lipid contents ranged from 8%–11% dry weight (DW) with phospholipids being the main lipid component (43–56% of total lipid). Storage lipids (triacylglycerols) made up 18–26% of total lipid. The relatively low lipid contents may reflect the early development stage of the specimens examined. The data presented give the first information on geographical and vertical distribution patterns of early life stages of G. glacialis in the high-Antarctic Weddell Sea, as well as on their lipid content and composition.

Temporal variations of the aerosol optical depth and transmission coefficient of the atmosphere are considered using data from Mirny Observatory, Antarctica. Year-to-year variability of these parameters is determined mainly by stratospheric aerosol pollution due to volcanic activity. A considerable increase of atmospheric turbidity has been observed since the end of September 1991. This phenomenon seems to be associated with the Mount Pinatubo volcanic eruption.

The data presented provides new information on the distribution of Antarctic squids and on the summer diet of the emperor penguins. The diet of 58 adult emperor penguins (Aptenodytes forsteri) on the fast ice of the Drescher Inlet, Vestkapp Ice Shelf (72°52′S, 19°25′W) in the eastern Weddell Sea was investigated. Prey consisted principally of squid, fish, krill, amphipods and isopods. Squids were identified by the lower beaks and allometric equations were used to estimate the squid biomass represented. Beaks occurred in 93% of the stomach samples. Each sample contained a mean of 27 beaks (range 1–206). Ninety-two percent of the squids could be identified by the lower beaks and belonged to four families (Onychoteuthidae, Psychroteuthidae, Neoteuthidae and Gonatidae). The most abundant squid was Psychroteuthis glacialis which occurred in 52 samples with lower rostral lengths (LRL) ranging from 1.4–7.2 mm. Forty-five samples contained Alluroteuthis antarcticus (LRL range 1.8–5.8 mm), 17 Kondakovia longimana (LRL range 4–12.1 mm), and four Gonatus antarcticus (LRL range 4.1–6.1 mm). In terms of biomass K. longimana was the most important species taken by the penguins comprising 50% of total estimated squid wet mass (245348 g) in 1990 and 48% in 1992 (154873 g). However, if only fresh beaks were considered for estimations of squid consumption, i.e. beaks that have been accumulated for not longer than 5–6 days in the stomachs, squid diet was of minor importance. Then total squid wet mass accounted for only 4809 g in 1990 and 5445 g in 1992 which implies that one penguin took c.30 g squid d−1 with P. glacialis and A. antarcticus being the most important by mass. The prey composition suggests that emperor penguins take squid at the steep slope regions of the eastern Weddell Sea.