ALBERT

Beschreibung: 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.

Beschreibung: 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.

Beschreibung: The presence of Stoloteuthis leucoptera in the Mediterranean is recorded on the basis of three specimens, including an adult male, caught by IKMT and by commercial otter-trawl in the Ligurian Sea. The hypothesis of a recent immigration is discussed. The list of Mediterranean cephalopods (Mangold Wirz, 1963; Torchio, 1968; Bello, 1986; Mangold & Boletzsky, 1987) includes the Sepiolidae of the subfamily Heteroteuthinae, whose members are supposed to be pelagic throughout their life cycle. Mangold Wirz (1963) recognizes in the Mediterranean fauna the unique species Heteroteuthis dispar, the other authors include H. atlantis Voss, which Voss himself (1955) reported at Messina. To this group may now be added Stoloteuthis leucoptera (Verrill, 1878) a species until now recorded in limited Atlantic areas. Verrill (1881) wrote “This species is an exceedingly beautiful one, when living, owing to the elegance and brilliancy of its colours and the gracefulness of its movements. In swimming it moves its fins in a manner analogous to the motion of the wings of a butterfly.”

Beschreibung: Sexual reproductive cycles of a Florida, U.S.A., population of four Caribbean commercial sponge species, Hippospongia lachne, Spongia barbara, S. cheiris and S. graminea, were determined by analysis of tissue samples collected over a three-year period. Spermatogenesis in these species was studied using light and transmission electron microscopy. The production of male gametes occurs in cysts within the endosomal tissue of mature specimens. Reproductive elements within an individual cyst develop synchronously while development between cysts is asynchronous. All available evidence suggests that these species are dioecious. Spermatogonia differentiate directly from choanocytes in situ. All cells of the chamber lose their collars and flagella and undergo mitosis to produce primary spermatocytes, each possessing a single flagellum. The ratio of nucleus to cell diameter in these cells is almost double that of choanocytes. Circumstantial evidence suggests that primary spermatocytes undergo meiosis to produce four spermatids, but confirmational chromatid linkage figures are still lacking. The mature spermatozoa lack both intermediate segments and acrosomes. Male gametes displayed a bright yellow-white autofluorescence when excited with blue light (460–485 nm).

Beschreibung: Squid on their spawning grounds feed mainly at night when they are more dispersed. In all, 28,5 per cent of squid sampled at night had food in their stomachs, whereas only 6,7 per cent of those collected by day had food. Most stomachs contained only a single prey species (90,8% of those analysed). Teleosts dominated the prey of squid collected at night (58%M), followed by crustaceans (25%), polychaetes (9%) and cephalopods (3%). By day the prey was dominated by cephalopods (61%), followed by teleosts (20%), crustaceans (14%) and polychaetes (2%). Bregmaceros sp. was the most frequently identified teleost, Loligo vulgaris reynaudii (cannibalism) the dominant cephalopod, ?Betaeus sp. (Alpheidae; pieces of coral were also found) the commonest crustacean and Nereis sp. the commonest polychaete. There were seasonal differences in the diet too: squid caught during summer seemed to have similar proportions of the four main prey components. Also, the incidence of feeding was higher than in winter. There were, however, no significant differences in stomach mass expressed as a percentage of body mass between day and night nor between season nor between sexes. The average stomach mass of all samples was 0,6 per cent of body mass, less than on the feeding grounds, where it is generally about 2 per cent.

Beschreibung: The enoploteuthid cephalopod Abraliopsis lineata is re-described and its generic position discussed. Specimens for the present study were captured during the Indian Ocean Expedition of RV Meteor in 1987, where the species occurred in considerable numbers. The geographical distribution of A. lineata is described and discussed. The detailed analysis of the photophore pattern of the present specimens differs from the original description. The diagnostic features in the male, especially the structure of the hectocotylus which separates A. lineata easily from the members of the subgenus Pfefferiteuthis, are outlined. The morphological differences which separate A. lineata from A. gilchristi, the only other member of the subgenus Micrabralia, are summarized.

Beschreibung: Larval behaviour, settlement, and metamorphosis were investigated in four Caribbean commercial sponges, Hippospongia lachne, Spongia barbara, S. cheiris and S. graminea, using light and transmission electron microscopy. The parenchymella larvae of these viviparous and gonochoristic species have an average size of 350 μm by 420 μm when released. Symbiotic bacteria occur intercellularly in both larvae and post-larvae. Laboratory behavioural studies demonstrate that free-swimming larvae display directional swimming with constant lateral rotation and negative phototaxis. Larval settlement occurs 26–56 hours after release from the parent and involves the formation of a basal lamella between the post-larva and substrate. There is no evidence of larval substrate selection by type or orientation. The canal system begins to form six days after settlement and oscules are apparent eleven days post-settlement. Available evidence suggests that larval ciliated epithelial cells are terminally differentiated and do not appear to contribute to formation of post larva or adult in this group of Porifera.

Beschreibung: To evaluate the feasibility of feeding Sepia officinalis on artificial food, a food pellet consisting of Palaemon serratus powder and alginate as binding agent was developed and tested. Six of seven cuttlefish clearly ingested the artificial food during the ten days it was supplied.

Beschreibung: Knowledge concerning biology of two loliginids and three sepiids which are found in the Japanese waters was reviewed including unpublished information of the authors. The swordtip squid, Photololigo edulis, is one of the most important resources for the coastal fisheries of Kyushu and the prefectures facing the southwest Japan Sea. This species is the only species of genus Photololigo found along the Japanese mainland coast and is easily distinguished from other loliginids, by the light organs on the ink sac. The species is distributed from southern Japan to the Red Sea. The spawning season extends throughout the year. Egg cases are laid in clusters on the sandy bottom. The life span is about one year. In the juvenile stage they feed on Crustacea and after reaching pre‐maturity they prey mainly on fish, but many have empty stomachs. Most catches are made by jigging and trawler. The fishing season extends throughout the year. The fishing grounds are widely spread over the continental shelf. Annual catches are around 25 000 metric tonnes. Although this level varies from year to year, it is fairly stable. Fishing has probably little effect on the stocks. The spear squid, Heterololigo bleekeri, can be easily distinguished from other loliginids by its shorter tentacles. The species is endemic in the Far East waters. The stocks are larger in the north. The spawning season is winter in south Japan, and from spring to early summer in north Japan. Egg cases are laid beneath the undersurfaces of firm substances. The life span is about one year. Its feeding behaviour is similar to that of the swordtip squid. Catches are made mainly with bottom trawler and fixed nets from autumn to spring. Annual landings fluctuate widely from year to year. Several prefectures along the northern Japan Sea coast are promoting the large scale development of artificial spawning beds of the species to increase the stocks. The three sepiids, golden cuttlefish. Sepia esculenta, kisslip cuttlefish. Sepia lycidas, and spineless cuttlefish, Sepiella japonica are important in mainland Japan. Those three spawn from spring to early summer in the innermost waters of semi‐enclosed inlets. Eggs are laid in batches of 50–300 every day for 3–4 days followed by a rest period of 1–2 days. This pattern is repeated until several thousands of eggs have been laid. The life span of Sepia esculenta and Sepiella japonica is one year. They feed mainly on decapod crustaceans and fish but as growth proceeds the proportion of fish increases. They are fished mainly by cuttlefish trap and beam trawler. In the early 1960s annual landings were 20 000 metric tonnes but since 1980 catches have decreased below 10 000 metric tonnes. Of the three species, the stock of Sepiella japonica is the most fluctuable. Judging from the result of the stock assessment studies on Sepiella japonica in the western Inland Sea, their stocks have been over‐exploited.