Loligo vulgaris (Cephalopoda: Loliginidae) is a commercially important species in the cephalopod trawl fishery in the Saharan Bank (21–26°N). This study on squid in central-east Atlantic waters aims to examine some important aspects of its reproductive biology. In the period from May 1993 to April 1994 monthly samples of L. vulgaris were collected from this commercial trawl fishery. The maturation pattern for males and females was described from the proportion of immature, maturing and mature animals in the samples and using a maturation index. A range of reproductive indices derived from the morphometrics of the somatic and reproductive systems were also estimated to provide comparative information. The proportion and an abundance index of mature and immature animals in commercial landings in the period 1983–1994 were calculated to provide comparative results of maturity and recruitment respectively. Peaks of mature animals were mainly seen between November and January. The summer months exhibited the maximum recruit abundance. Age determinations were also undertaken in order to obtain the hatching peaks and to complete the proposed life cycle of L. vulgaris on the Saharan Bank. A main hatching peak was observed in spring, particularly in May. The age–size relationship suggests differences related to sex and possibly to hatching season. The wide range of size at maturity observed in male L. vulgaris is analysed and discussed. Males showed a seasonal pattern in size at maturity. The dorsal mantle length–body weight relationship and the sex ratio were determined. The sex ratio exhibits a seasonal pattern in relation to body size. Results are compared with information on this species from European waters.

Prey populations, patterns of availability, and dispersion of prey can have farreaching effects on numbers and range-sizes of terrestrial Carnivora (Macdonald, 1983; Kruuk & Parish, 1982; Kruuk & Macdonald, 1985). These parameters may therefore also affect populations of otters Lutra lutra, living in the sea around Shetland, U.K., as well as populations of fish-eating birds there. This paper presents observations on fluctuations in numbers and activity of several species of demersal fish, over a 3½ year period, along a coast in Shetland. It aims to provide information on the distribution and availability of these species to some predators, especially to the otter, but also to the heron Ardea cinerea, the black guillemot Cepphus grylle and others.

Waves breaking on rocky shorelines impart large forces on intertidal organisms, sometimes dislodging individuals. Dislodged individuals may be deposited in habitats that have a greater risk of predation or that prevent return to preferred regions on the shore. Thus, dislodgement is often assumed to be lethal. We experimentally dislodged Littorina keenae snails from high in the intertidal zone to test the likelihood of survival. Under a variety of wave conditions, we measured return rates to the high shore of 54–90%, so in this species, dislodgement is not equal to death. Snails showed a strong preference for returning to the approximate tidal height from which they were dislodged, but we found no evidence of widespread homing behaviour back to the original site of dislodgement.

the population structure and reproductive biology of mustelus schmitti was analysed during autumn (1994, 1995) and spring (1994) in the rio de la plata oceanic front. the samples consisted mainly of adult males and immature females, indicating that nursery areas are situated elsewhere. in autumn, the highest female densities occurred between 36°s and 35°s, with densities decreasing further south, and high male densities occurred over all latitudes of the study area. in spring, both sexes occurred north of latitude 36°30′s. males attained maturity at 59 cm total length (tl), and females at 72 cm tl. litter size varied from one to ten in spring and two to nine in autumn, with embryos ranging from 9 to 26 cm and 7 to 26 cm tl respectively. the mean tl of embryos was significantly higher in spring (22 cm), suggesting that parturition occurs in late spring and summer. litter size was found to increase with female tl.

This paper analyses the population dynamics, growth and feeding ecology of Dicentrarchus labrax in order to gain a better understanding of its present role in the western Dutch Wadden Sea ecosystem. Otolith analysis showed that the population is mostly comprised of individuals aged 3–5 years old and between 20 and 45 cm in length. In autumn, 0-group juveniles are also an important part of the population. Both juveniles and adults use the area as a feeding ground exhibiting an opportunistic feeding strategy that relies on available prey, especially the brown shrimp Crangon crangon. Stomach content analysis and nitrogen stable isotope analysis showed an ontogenetic shift towards piscivory and a general decrease in the dominance of invertebrates with increasing size. Over the last 50 years, large between-year fluctuations in D. labrax abundance have been observed with an underlying increasing trend from about 1990 until 2007 followed by a subsequent decline. Spring abundance showed significant relationships with temperature and salinity while autumn abundance was only related to temperature. Spring and autumn D. labrax abundance were also strongly related to abundance of brown shrimp C. crangon prey. Long-term trends in temperature and salinity in the area suggest that environmental conditions for juvenile growth have become optimal, resulting in increased abundance since the mid-1980s. Continued monitoring of the dynamics of this species in the Dutch Wadden Sea is important to understand and anticipate the effects of climate change on the D. labrax population and its role in the local food web.

This study presents new information on feeding habits of Guiana dolphins, Sotalia guianensis, in south-eastern Brazil, together with new regression equations to evaluate the weight and length of fish from otoliths, showing an overview on the knowledge about this species’ diet in this area. Eighteen stomach contents had been analysed and compared to 180 samples collected in another eight feeding studies. The analysed specimens were either incidentally caught in gillnets used in coastal waters by the fleet based in the Cananéia main harbour (25°00′S 47°55′W), south of São Paulo State, or found dead in inner waters of the Cananéia estuary between 2003 and 2009. Based on the index of relative importance analysis, the most important fish species were the banded croaker, Paralonchurus brasiliensis. Doryteuthis plei was the most representative cephalopod species. Stellifer rastrifer was the most important fish species observed in dolphins in inner estuarine waters and P. brasiliensis in recovered dolphins from coastal waters. Loliguncula brevis is the only cephalopod species reported from dolphins found in inner estuarine waters up to date. Doryteuthis plei was the most important cephalopod species observed in coastal dolphins. When considering other feeding studies, the most representative fish family in the diet of S. guianensis was Sciaenidae, which is mainly represented by demersal fishes. The main preys of S. guianensis are abundant in the studied areas, which may indicate an opportunistic feeding habit. The majority of them are not the most important target species by the commercial fishery in south-eastern Brazil.

The functional morphology of the buccal mass of 23 species of cephalopod (Octopoda, 4 species; Teuthoidea, 17; Sepioidea, 2) was investigated by gross dissection, histology and observations on fresh preparations. Cephalopod beaks lack a joint or articulation point. The jaws slide and rotate around an area rather than a fixed point. During closing the superior mandibular muscle (SMM) provides the force of a bite and the largest movement vector, whilst the inferior mandibular muscle (IMM) acts to retract the upper beak, causing shearing action. Dorsal portions of the lateral mandibular muscles (LMM) flex the upper beak walls outwards, probably to accommodate the backwards sweep of the radula and buccal palps during closing. To open the beaks, the ventral portions of the lateral mandibular muscles pull the rear lateral walls of the two beaks towards each other, moving the lower beak back relative to the upper.

The caridean shrimp Alvinocaris muricola has been observed forming high density populations over mussel beds on the giant pockmark cold seep site Regab in the Gulf of Guinea at 3150 m depth. Samples were collected using the ROV Victor 6000, a beam trawl and a TV grab from two sites. The specimens were sexed and measured for population structure analysis. In one sample the sex ratio was 1:1, but the other sample had a sex ratio significantly biased towards females. The maximum size of females is larger than males. A sub-sample was used for gametogenesis and fecundity analysis. The oogenesis and spermatogenesis of A. muricola is characteristic of caridean shrimps. The oogonia proliferate from the germinal epithelium and develop into previtellogenic oocytes that migrate to the growth zone. Vitellogenesis starts at 80–100 μm oocyte size and the developing oocytes are surrounded by a monolayer of accessory cells. The maximum oocyte size was 515 μm. There was no evidence of synchrony in oocyte development, with all oocyte stages present in all ovaries analysed. However, seasonal sampling would be necessary to confirm the lack of seasonality in reproduction. In males, the sperm develops in sperm sacs in the testis. As in all caridean shrimp, the broods of A. muricola are held on the pleopods P11 to P14. Total fecundity was related to female size and ranged between 1432 and 5798 embryos. Within a brood all embryos are at the same stage of development, but three different stages were identified in different females, with no clear seasonal trend. The embryos were small, with mean dimensions of 0.66×0.55 mm, suggesting planktotrophic larvae and a potential extended larval development.

The pygmy killer whale (Feresa attenuata) is an offshore, tropical and subtropical delphinid found in the Atlantic, Indian and Pacific Oceans. The species has only recently been studied, mostly from specimens collected from strandings. While over 52 reports exist for the Atlantic Ocean, only one record exists for the Caribbean Sea. A new record of a mass stranding of pygmy killer whales from the British Virgin Islands is documented and the pathology and life history of the specimens is described, associating the stranding process with the meteorological and oceanographic disturbance of Hurricane Marilyn, which devastated the Virgin Islands a day prior to the stranding. This stranding event constitutes the sixth known mass stranding for the species worldwide, the first record for pygmy killer whales for the northeastern Caribbean and the second for the entire Caribbean Sea.

The present report deals with the young fish which were collected in the neighbourhood of Plymouth during the summer and autumn of 1919, from the beginning of July to the end of September, by small meshed nets operated from the Association's steamer Oithona. It is a supplement to Dr. Allen's report on the “Post-larval Teleosteans collected near Plymouth during the Summer of 1914,” published in Vol. XI, No. 2 (May, 1917), of this Journal, and to the writer's “General Report on the Larval and Post-larval Teleosteans in Plymouth Waters” in Vol. X, No. 2 (June, 1914).

The total number of fish examined amounts to 16,400, which are referable to 24 families, 39 genera and 71 species. All the forms are stages in the life histories of fishes, which are well known as adults.

The pelagic young of the species of Gadus and Pleuronectes are poorly represented in the catches, but this is not surprising when one considers the lateness in the year when the hauls were made. Similarly the young of early spawners like the Herring are absent.

The pelagic young of the Hake (Merluccius merluccius) appear for the first time since investigations with small meshed nets have been undertaken in the Plymouth area, the only other records of their occurrence in the western area of the English Channel being those which were taken by the Danish research steamer Thor, vide Schmidt (1909).

Orton's account of ciliary mechanisms on the lophophore of Crania anomala (Müller) is confirmed. Observations on the natural orientation of the lophophore have modified his account of the filter-feeding water currents. As in other brachiopods the lophophore divides the mantle cavity into inhalant and exhalant chambers with separate apertures to the exterior. The inhalant chamber has two apertures, is ventral in position, and extends into the interior of the spiral brachia; the exhalant chamber is dorsal in position and has three apertures. The development of the lophophore in the later growth stages is described. Both in development and in the form and function of the organ in the adult, the lophophore of C. anomala closely resembles that of the articulate species Tegulorhynchia nigricans (Sowerby): it is suggested that this reflects an inherent limitation on the possible variety of lophophores in brachiopods.

A total of 25 species of ascidians were collected in the Mar Piccolo of Taranto, a semi-enclosed Mediterranean basin. Three are non-indigenous for the Mediterranean Sea: Microcosmus squamiger, Polyandrocarpa zorritensis and Distaplia bermudensis. The substrate features, season and depth affect the distribution of ascidians in the study area. Some species, such as Pyura dura and Pyura microcosmus, were found only on artificial substrates, while Ascidiella aspersa was almost exclusively recovered on natural bottoms. Seasonal variation in the ascidian distribution and abundance seems to be due mainly to their biological cycles, larval recruitment and adaptation. During the autumn and winter the most abundant species were Clavelina phlegraea and Ciona intestinalis, while A.aspersa was particularly abundant during spring. Depth and more directly light intensity play an important role in ascidian distribution. In the upper few metres the shallow-water species Polyandrocarpa zorritensis was abundant due to its photopositive larvae. Even though the distribution and abundance changed significantly between substrates, seasons and depths, the most abundant species in the Mar Piccolo of Taranto were Clavelina phlegraea, Ciona intestinalis and Styela plicata all of which are able to tolerate the variations in environmental conditions, low rate of water renewal and continuous silting of this semi-enclosed sea. Assuming the role that the above mentioned species have as marine pollution indicators and the abundance recorded for some of them, a high degree of environmental stress can be confirmed for the Mar Piccolo of Taranto. A comparative list of the ascidians recorded in this and previous studies is also reported.

We describe a new species of Crambionella, C. helmbiru, from central Java, Indonesia. The combination of the mean number of lappets per octant (14), presence of foliaceous appendages amongst frills on oral-arms, absence of tubercles on the velar lappets, proportion of terminal club length to oral-arm length (0.28), and the body colour distinguish this species from three previously described congeners. In addition, the analysis of partial sequences of the cytochrome c oxidase subunit I gene indicate substantial genetic differences from both Crambionella orsini and Crambionella stuhlmanni, supporting the validity of this new species. A combination of morphological and genetic approaches determined that the remarkable differences in exumbrellar colours observed in specimens are simply intra-specific variation. Surprisingly, this species has been commercially harvested for more than 20 years and is well-known to the local people in the region, yet it had remained unknown to science until this point. The commercial fisheries targeting this formerly unknown species are also described in detail.

When scanning electron microscopy became integrated with X-ray micro-analysis, it became an easy matter to localize an object and perform a semi-quantitative elemental analysis of atoms of atomic number 11 or higher using an energy dispersive spectrometer. This technique is used in the present study to determine the chemistry of the statoliths of eight hydromedusae, two scyphomedusae, one cubozoan and a ctenophore with respect to their comparative biomineralization and the relationship of the mineral to their taxonomy.

In the Southern Bight of the North Sea, off the Belgian coast, exists a series of parallel sublittoral sandbanks, the Flemish Banks, situated in a southwest-northeastern direction, 15–25 km long and 3–6 km wide. They are separated by channels, 4–6 km wide, and rise about 25 m above the surrounding sea-floor (Fig. 1). These sandbanks resulted from the accumulation of sandy deposits of glacial origin sedimented by the giant stream draining the waters from the present Rhine, Meuse, Scheldt and Thames before the Flandrian marine transgression about 12000 years ago. When from boreal times onwards the North Sea became slowly inundated, a connexion existed with the small English Channel which gradually enlarged, resulting in the very strong tidal currents which are responsible for the present geomorphology of the region.

The bristle-bearing receptors on either side of the trunk in Oikopleura are connected to the caudal ganglion by the axons of central cells which form electrical synapses (gap junctions) at the bases of the receptor cells. The same axons also form similar synapses with epithelial cells adjacent to the receptors. Direct mechanical stimulation of the receptor processes evokes changes in the locomotor rhythm of the same kind as evoked by action potentials propagated in the epithelial cells. This remarkable arrangement is suggested to be a consequence of the reduced numbers of cells in larvaceans.

The ciliate Cryptocaryon irritans Brown, 1951 is a parasite of tropical marine fishes, being recorded chiefly from coral reef species (Laird, 1956; Burgess, 1978; Colorni, 1985). The disease, cryptocaryosis, accounts for fish mortalities in aquaria (De Graaf, 1973) and mariculture systems (Huff & Burns, 1981; Colorni, 1985; Kaige & Miyazaki, 1985; Rasheed, 1989); however, relatively few studies have been undertaken on the biology of C. irritans, as highlighted by Lorn & Dykova (1992). Sikama (1937) described the major features of the life cycle, infection of the fish epidermis alternating with a free-living phase of reproduction within a protective cyst. Most other investigations of C. irritans have been concerned with morphology (Sikama, 1937, 1938; Brown, 1951, 1963; Nigrelli & Ruggieri, 1966; Cheung et al., 1981; Colorni, 1988) with a recent work on the ultrastructure of the pellicle (Matthews et al., 1993). Little is known regarding the behaviour of free-living stages and the possible influence of environmental factors on transmission. Nigrelli & Ruggieri (1966) noted photopositive responses in theronts. The establishment and maintenance of C. irritans in mullet under controlled conditions (Burgess & Matthews, 1994) provided an opportunity further to investigate light in the survival strategy of this fish pathogen.

The redistribution of sediments by tidal streams has been demonstrated in a number of ways in the seas around Britain. For example, the numerous banks in the North Sea are elongated parallel to the streams, while the depth and position of certain channels are subject to such important changes in position that re-surveys have to be made each year or so (Robinson, 1956). In the same region the streams, reaching about a knot or more at the surface, have wrought a large area of sand floor into ridges normal to their path. Off the Dutch coast the grade of the sand (Jarke, 1956) decreases in their inferred direction of advance (Stride & Cartwright, 1958). Similar relief is found even at 90 fathoms near the edge of the continental shelf, at the western approaches to the English Channel (Cartwright & Stride, 1958). Pratje (1950) has shown that the occurrence and grade of loose sediment on the floor of the Channel as a whole is directly related to the velocity of the streams overhead.

In this article four species of Desmodoridae, Desmodora alberti sp. nov., Desmodora marci sp. nov., Desmodorella balteata sp. nov. and Desmodorella spineacaudata sp. nov. (Nematoda: Desmodoridae), are described from hydrothermal vents of the Pacific. The genus Desmodora is revised and lists of valid species are provided; four subgenera are reinstated as genera; Xenodesmodora is regarded as genus inquirendum. Definitions of some morphological structures are given.

Sperm whale social distribution was investigated in the Mediterranean Sea, using data collected during summer surveys from 1997 to 2002. Variations in the size of sperm whale schools/underwater aggregations were assessed using both visual and acoustic data. Individual body lengths were estimated acoustically, using the click inter-pulse intervals. Regional comparisons were undertaken, taking the 41° parallel as a north/south boundary. In the southern region, schools of up to seven sperm whales were sighted and calves were relatively frequent. The animals ranged between 8·6 m and 13·1 m long. In the northern region, school sizes were significantly smaller, with a maximum of three whales sighted at the surface. However, the acoustic survey showed that sperm whales form loose aggregations of up to five animals in certain areas. Whales detected in the north were 12·6 m long on average, and the body size range was relatively small. This summer survey demonstrated a segregation of males, in the north, from larger schools including calves, which seemed to be confined to the southern region.