The objective of the Naudur cruise (December 1993) of the submersible Nautile was to study the interaction among magmatic, tectonic, and hydrothermal processes at a very fast spreading mid‐ocean ridge axis. Twenty‐three dives were completed, both along and across the axis, in four areas located between 17°10′ and 18°45′S on the East Pacific Rise. Rock, sulfides, water, and biological samples have been collected along each of the segments. Two main types of segments have been distinguished, characterized either by the predominance of present‐day volcanic activity or by predominant tectonic activity. Linked to both types of activity, 69 hydrothermal sites have been discovered and sampled. They comprise four types, interpreted as successive evolutionary stages. The first are shimmering water sites which occur immediately after the formation of lava lakes and are characterized by large surface area and poorly developed associated fauna. The second, in areas dominated by recent volcanic activity, have waters venting directly from lava fissures and more focused discharge areas through black smoker chimneys. The third stage is represented by more mature hydrothermal vents and deposits, along the faults bounding the eastern side of the axial graben in tectonic‐dominated areas. The associated fauna is well developed. The fourth stage corresponds to the reactivation of volcanic activity with lava flows, young black smokers, and diffuse venting associated with the faults bounding the axial graben. Fluids collected range from 200° to 340°C and show a wide variability in chemical and gas composition. Within each of the explored areas, evidence of recent volcanic activity has been observed.

Abstract:The deep-water fauna of the Mediterranean is characterized by an absence of distinctive characteristics and by a relative impoverishment. Both are a result of events after the Messinian salinity crisis (Late Miocene). The three main classes of phenomena involved in producing or recording these effects are analysed and discussed:-Historical: Sequential faunal changes during the Pliocene and thereafter in particular those during the Quaternary glaciations and still in progress.-Bathymetric: Changes in the vertical aspects of the Bathyal and Abyssal zones that took place under peculiar conditions, i.e. homothermy, a relative oligotrophy, the barrier of the Gibraltar sill, and water mass movement. The deeper the habitat of a species in the Mediterranean, the more extensive is its distribution elsewhere.-Geographical: There are strong affinities and relationships between Mediterranean and Atlantic faunas. Endemic species remain a biogeographical problem. Species always become smaller in size eastward where they occupy a progressively deeper habitat.Thus, the existing deep Mediterranean Sea appears to be younger than any other deep-sea constituent of the World Ocean.

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Abstract. The present study investigated the growth, mortality, recruitment and food habits of Monacanthus tomentosus. A total of 1 038 specimens were collected by beach seine from the seagrass beds of Kotania Bay (Moluccas, Indonesia) from March 1988 to January 1989. Their "length-weight relationship" was W= 0.011 L 3"242" Based on the von Bertalanffy formula, the asymptotic length, L~, and growth coefficient, K, were determined as 11.79 cm and 0.86, respectively. Total mortality, Z, was low (2.033). Mean length of minimum capturable size (Lc) was 6.21 cm, and recruitment occurred throughout the year. Food consisted principally of gastropods (21.41 %), seagrasses (14.11%), sponges (12.11%), algae (10.82%), amphipods (9.76%) and sedentary polychaetes (9.29%). Pelecypods, opisthobranchs, isopods, copepods, ostracods, foraminiferans, bryozoans, ascidians, nematodes, mollusc eggs and fish eggs were found only in small percentages.