ALBERT

Description: The biology of the chokker squid Loligo vulgaris reynaudii on inshore grounds in the South-East Cape was studied by examination of trends in jig catches, length frequency analyses, length/weight relationships, analyses of maturity stages and SCUBA diving transects in a spawning area. Commercial catches probably reflected the influx of squid into shallow waters to spawn. Modal length at spawning was between 265 and 305 mm mantle length (ML) in males and between 175 and 195 mm ML in females. There was no modal progression to indicate growth, nearly all squid were mature, a percentage of males were spent, the level of feeding on the grounds was very low, and mantle walls were thinner than those of squid offshore. These factors all indicate that the squid population inshore had reached the end of its life cycle and was in the spawning phase. The sex ratio was biased towards males, an indication either of differential inshore migration or of greater longevity in males than in females. The frequency of occurrence of trawled egg capsules was highest in summer and all eggs were between 18 and 25 m deep. The preferred substratum for spawning appeared to be low-relief reef interspersed with coarse sand, and the stalks of egg capsules were always embedded in the sand to form individual clusters, as in most other loliginids. No evidence was found of post-spawning mortality in the areas examined.

Description: Oogenesis in four commercial Caribbean sponge species, Hippospongia lachne, Spongia barbara, S. cheiris and S. graminea, was studied using light and transmission electron microscopy. Eggs and embryos develop asynchronously in localized endosomal nurseries of these viviparous and gonochoristic species. Statistical analyses of specific morphological characteristics of reproductive elements have unequivocally identified four specific stages in the process of oogenesis. Oogonia undergo mitotic division to produce primary oocytes. Meiotic division occurs producing secondary oocytes which are fertilized before zygotes undergo major growth by phagocytosis and the transfer of nutrients through cytoplasmic bridges. During cleavage of the zygote, umbilici form between embryos and nurse cell layers and these function in the transfer of symbiotic bacteria and other mesohyl substances from the maternal parent to the embryo. These symbionts were observed dispersed between blastomeres of all young and maturing embryos and between internal cells of cytodifferentiated parenchymella larvae. Extracellular transfer of symbiotic bacteria from maternal tissues to developing embryos has not been reported in any other viviparous invertebrate.

Description: Before 1985, Martialia hyadesi (Cephalopoda: Ommastrephidae) in the Pacific Ocean was known only from the Eltanin Fracture Zone and Macquarie Island. A joint Japan‐New Zealand squid survey around New Zealand captured many immature ommastrephid squids. Gel electrophoresis confirmed the presence of immature M. hyadesi. Aspects of the external morphology are described. The distinctive tentacle club was evident in the smallest specimen examined, 19 mm dorsal mantle length (ML). Arm trabeculae were first evident in specimens of 40–50 mm ML. Immature squid were distributed around and southward of the Subtropical Convergence Zone. The presence of very small squid (〈 10 mm ML) indicated spawning on or near the Auckland Island Shelf.

Description: The beaks of 9,994 cephalopods of 61 species, obtained mainly from chick regurgitations of wandering albatrosses (Diomedea exulans L.) at Gough, Auckland, Antipodes, Prince Edward and Macquarie Islands and South Georgia, were used to specify and calculate the biomass of cephalopods consumed. Histioteuthidae were most important by numbers and biomass at Gough Island (in warmest seas), but Onycboteuthidae increasingly superseded them southwards; Kondakovia longimana formed 59 to 75% of biomass eaten at the three localities nearest the Antarctic Polar Front. Other important families were Octopoteuthidae, Cranchiidae, Architeuthidae (juveniles) and Ommastrephidae (South Georgia only). Most frequently eaten were Histioteuthis atlantica 13.7%, Galiteuthis glacialis 12.4%, H. eltaninae 12.0% and Kondakovia longimana 11.6%. Wandering albatrosses rearing chicks can forage at least to 3,000 km in a single foray, and may exploit an important food source about 1200 km from the nest (as in the probable commensalism of South Georgian birds with the Falkland Islands fishery). They feed, sometimes opportunistically, on cephalopods active or moribund at the surface, or discarded or lost by trawlers, cetaceans or seals. Vertically migrating cephalopods, especially bioluminescent species, are disproportionately frequent in their non-commensal diet, suggesting that they often feed at night.

Description: A link is proposed between the processes that led to the evolution of large species of squid and the highly variable, cyclic recruitment seen in squid fisheries. Maximum growth requires maximal feeding and minimal routine metabolism at optimum temperatures, which decrease as squid grow. Topographically induced upwelling zones, inshore of western boundary currents, provide productive environments with appropriate temperatures for all life stages. Most squid are small and live in the tropics or subtropics; locomotor constraints prevent them from swimming long distances. Long annual migrations to spawn upstream in current systems require short-lived squids to maximize rates of growth. Therefore, such systems provide the opportunity and a powerful selective advantage for large size and rapid growth. Increased fecundity and cannibalism provide additional directional selection for large individuals. Current systems show food production peaks (blooms); paralarval release must match these to increase survival. Because squid are semelparous, disruption of delicately balanced lifecycles by physical events can virtually annihilate stocks. Recovery probably requires that populations of large squid "re-evolve" from smaller, more-stable tropical populations of small squid. This recovery phase may extend the "down-side" of abundance cycles. Studies of squid/current systems have focused on western boundary currents, but the Illex complex also associates with eastern boundaries. Such populations are generally smaller than in larger systems, supporting the hypothesis, but more detailed comparisons are required.

Description: During a cruise in March 1988 dedicated to investigation of the marine resources of South Africa's continental slope, 62 species in 22 families of Cephalopoda were collected from the Cape Canyon and Cape Point Valley. Multivariate analysis revealed a clear distinction between cephalopods of the upper and lower continental slope in both benthic and epibenthic habitats. Todaropsis eblanae and Todarodes angolensis were indicator species for the upper slope benthic, from 300 to 500 m, but on the lower slope, in 700–900 m of water, they were replaced by Histioteuthis miranda and Opisthoteuthis agassizii. In the epibenthic, both upper and lower slopes were dominated by Abraliopsis gilchristi and Lycoteuthis ?diadema, but other species characteristic of the lower slope were the oceanic species Mastigoteuthis hjorti, Ctenopteryx sicula and Taonius sp. A. Cranchia scabra indicated the presence of oceanic water at stations 700–900 m deep. Other species of significance in the catches were Todarodes filippovae, Histioteuthis macrohista, Rossia enigmatica and Bathypolypus valdiviae. Species affinities indicate that the cephalopod fauna of the southern African continental slope includes the following zoogeographic components: southern African endemic, circum-Subantarctic species associated with Antarctic Intermediate Water, circum-global southern tropical/subtropical, tropical Indo-Pacific and cosmopolitan tropical/subtropical.

Description: Literature on trophic relationships in the Benguela ecosystem has stressed the importance of cephalopods as prey of groundfish. The groundfish community of the shelf and upper slope of southern Africa is dominated by the Cape hakes, and the results presented (1984–1991) confirm that both species of hake are important predators of cephalopods, especially taking into consideration the abundance of hake in the ecosystem. However, geographic, seasonal and species variability are evident in the patterns observed. The main prey species are Sepia spp. (predominantly Sepia australis), Loligo vulgaris reynaudii, Todaropsis eblanae and Lycoteuthis ?diadema. The last-named is an important food organism for fish. Its systematic status needs revision, however. Qualitative results of studies of cephalopod predation are also provided for kingklip and monkfish.

Description: Cephalopods of importance in the Benguela ecosystem include Loligo vulgaris reynaudii, Todarodes angolensis, Todaropsis eblanae, Lycoteuthis ?diadema, Sepia australis, Octopus spp. (up to three species) and Argonauta spp., and possibly also Ocythoe tuberculata and Rossia enigmatica. Species which may prove important as a result of further research are Lolliguncula mercatoris, Ommastrephes bartramii, Todarodes filippovae, Histioteuthis miranda and Abraliopsis gilchristi. "Importance" is defined on the basis of "survey abundance" (including commercial fisheries) and their trophic links with other organisms. Use of the latter criterion indicates that Sepia australis, Todaropsis eblanae and Lycoteuthis ?diadema are sufficiently abundant to be exploited by fisheries. Unknown factors are dispersal, availability and market considerations. The only examples of cephalopods feeding on commercial species of fish are Loligo v. reynaudii feeding on anchovy Engraulis capensis and Cape hakes Merluccius capensis and/or M. paradoxus in the southern Benguela and Todarodes angolensis preying on Cape hake in the northern Benguela. Such feeding is opportunistic and is not believed to threaten the fish stocks. Predators of cephalopods are mostly opportunistic, switching to other prey when cephalopods are not available. There is no evidence that such predators pose a threat to the Loligo fisheries. The opportunistic nature of cephalopods as prey and predators makes quantification of predation (in both directions) difficult. Data for such quantification are, as yet, unavailable.

Description: The present study contributes new information on the cephalopods off Namibia, contains the first record of Ornithoteuthis volatilis (Sasaki, 1915) in the Atlantic, and adds records of six species in the Benguela Current and three species in Namibian waters. The presence of certain species seldom encountered in the Benguela Current has been confirmed. A compilation of the cephalopod fauna off Namibia had also been included, listing 65 species. Additional morphological data on Stoloteuthis leucoptera, Lycoteuthis lorigera, Architeuthis sp., Pholidoteuthis boschmai, Ornithoteuthis volatilis, Eledone nigra, and Graneledone sp. have been provided. The status of the genus Lycoteuthis has been reviewed in the light of the first collection of Lycoteuthis lorigera (Steenstrup, 1875) males in the Atlantic, and Lycoteuthis diadema (Chun, 1900) has been considered to be a synonym for Lycoteuthis lorigera

Description: The results of ichthyoplankton surveys carried out by the Instituto Nacional de Pesca (INAPE) in the Argentine–Uruguayan Common Fishing Zone (AUCFZ) in summer 1980 and the winters of 1980–1982 are presented. In addition, the results of joint research with INIDEP, the Argentine and Japan Fisheries Agency, on larvae, juveniles and adults of the short-finned squid Illex argentinus carried out in winter 1989 are given, as are data obtained during the joint sardine and anchovy recruitment project carried out by R.V. Meteor in November/December 1989. The short-finned squid Illex argentinus is the most important cephalopod resource of the area, and an extended fishery is carried out on the Patagonian shelf and in the proximity of the Falkland Islands. The fishing season in the AUCFZ, for pre-spawning and spawning animals, extends from early autumn to winter (March–August). Abundance of rhynchoteuthion larvae (417–485 larvae·10 m−2) was greatest in winter in surface temperatures of 12,1–16,9°C and surface salinities of 34,8 – 35,2 × 10−3. The distribution of the larvae is related to the western boundary of the Brazil Current and the convergence front.