Settlement of Concholepas concholepas (Gastropoda: Muricidae) on natural and artificial substrata was studied between April 1999 and March 2001 at two sites in central Chile; the Las Cruces Marine Reserve and El Quisco Management and Exploited Area. Four different artificial materials were tested in the low intertidal zone during 1999 settlement season to determine their properties as settlement and microhabitat substrata for competent Concholepas larvae. Globular pads made of plastic filaments were identified as the best artificial collectors, exhibiting overall higher settlement rates than rock plots and lower variability among replicates within a given site. Thus, subsequent monitoring of settlement used only these globular pads that were replaced twice monthly. The temporal pattern of settlement was remarkably similar from year to year, starting at the end of austral winter (August–September) and ending in summer (December–January), defining a temporally restricted settlement season. Settlement at two sites within the Marine Reserve of Las Cruces was significantly higher than at sites in El Quisco. However, during the second settlement season, an additional site at El Quisco exhibited settlement rates comparable to those observed at Las Cruces. The results show that Concholepas settlement varies significantly over scales of several hundreds of metres as well as tens of kilometres, probably due to differences in coastal oceanographic conditions.

This paper reports the observations recorded on the arcid clam, Anadara demiri, from its first reporting in the Adriatic Sea three years ago, when its presence only was noted, to the present day when its invasive potential is confirmed. Repeated recruitment events were observed and confirmed by the co-existence of two or more cohorts within the population. Anadara demiri appears to be a year-round spawner with two spawning peaks (late winter and summer). Together with the congeneric invader, Anadara inaequivalvis, it has colonized the external belt of the fine well-sorted sand biocoenosis where they may numerically dominate the benthic community. Anadara demiri appears to have gained full status as a component of the Adriatic Sea coastal benthic community despite its very recent first entry. Numerous features make it a strong competitor among which is the ability, retained into adult life, of attaching, by means of byssus threads to all kinds of hard substrata, particularly to other live molluscs such as the gastropod Aporrhais pespelecani and the bivalves Anadara inaequivalvis and Chamelea gallina. The presence of species actively interfering with A. demiri in various ways (the polychaetes, Polydora sp. and Sabellaria spinulosa, that bore into and foul the shell, respectively, and the predatory asteroid Astropecten irregularis) is discussed.

The hepatic photophores of species of Sergestes (organs of Pesta) contain fluorescent paracrystalline platelets which are the sources of the luminescence. The cells containing these crystals are contiguous with cells filled with lipid droplets which act as a diffuse reflector. The optical properties of the organ as a whole derive from the different arrangement of the various regions in the mosaic of individual tubules. The hepatic photophores of Parapandalus, Thalassocaris and Chlorotocoides have a similar anatomical position but differ considerably in structure. They do not contain paracrystalline material and they have a diffuse reflector, probably not composed of lipid, which is separated from the tubules that make up the photocytes. The organs in Thalassocaris and Chlorotocoides are very similar in structure. Luminescence in the photophores of all four genera is probably intracellular.

Serpuloidea were collected by diving within 45 m depth, by indirect sampling in deeper waters (50 and 81 m), and among the fouling settled on oceanographic instruments at various depths (10, 50, 80 and 83 m depth). A total of 33 species or subspecific taxa was found: 25 Serpulidae and eight Spirorbidae. All the species collected are already known for the western Mediterranean and have Atlantic–Mediterranean or worldwide distribution. Several of these, however, may be species-complexes hiding species with restricted geographic ranges. No Lessepsian migrants were found. The number of species found at vent sites was significantly higher than that found at non-vent sites, although no vent-obligate species were recognized. Hydrothermal vents might influence serpuloidean richness through four main mechanisms: (i) increasing food sources to these filter-feeders, due to the chemiosynthetic production by vent microbiota; (ii) enhancing the development of biogenic carbonate mounds, which provide habitats for encrusting and cryptic species; (iii) inducing advective mechanisms that concentrate larval stages in the vicinity of vents and thus favouring recruitment; (iv) creating, through the periodic emission of toxic fluids, a regime of `intermediate disturbance' that allows a larger number of species to coexist.

Lipid and fatty acid composition in Gammarus aequicauda from Mar Piccolo (Ionian Sea, southern Italy) were studied during the spring months. Simultaneously, samples of the macroalgae Chaetomorpha linum were also collected from the same area. During these months Chaetomorpha linum was the main food source of Gammarus aequicauda. The main lipid classes were phospholipids (PL) and triacylglycerols (TG) both in Gammarus aequicauda and in Chaetomorpha linum with similar concentrations. But PL was the main lipid class in Gammarus aequicauda and TG in Chaetomorpha linum. On average unsaturated fatty acids represent the preponderant part in both G. aequicauda and C. linum. Gammarus aequicauda had a higher level in monounsaturated fatty acids (MUFA), on the contrary polyunsaturated fatty acids (PUFA) were the dominant unsaturated fatty acids in C. linum. Both were characterized by high levels of 18:0, 18:1(n-9), 20:5(n-3) and 20:4(n-6), in particular C. linum had a high proportion of 14:0 and the ratio of 18:1n 9/18:1n 7 was high.

The development of the polychaete Capitella sp. Y from Estero del Yugo, Mazatlán, Mexico was studied under culture conditions. Capitella sp. Y has a lecithotrophic development with the production of ciliated metatrochophore larvae. A high variation in size and duration of the different developmental stages was observed, as with most of the Capitella species previously described. The median survival time was estimated as six months. The Capitella sp. Y population consists of males, females and hermaphrodites (protandrous and proteroginous individuals). Differences in developmental modes among the Capitella capitata species-complex have indicated that Capitella sp. Y do not belong to any of these previously described species. This study has shown that hermaphroditism is favoured when density of individuals is low, especially in protandrous specimens. It is suggested that hermaphroditism, as well as the ability of self-fertilization observed in Capitella sp. Y enhances the success of the population in natural environments.

Mustelus schmitti (Carcharhiniformes: Triakidae) studied in the present work were caught incidentally in the shrimp fishery of the south of Bahía Engaño (Patagonia, Argentina). This bay is a shallow water, high productivity coastal area where shrimps and small fish are abundant throughout the warmer months. Young of M. schmitti are found in the bay from late spring to mid autumn. The analysis of stomach contents showed that the young feed mainly on crustaceans; the shrimp Artemesia longinaris being the main prey item. The bay serves as a nursery area for M. schmitti, and the length range and umbilical scars present in all the specimens studied revealed that the individuals were newborns.At Bahía Engaño, fishing trawls in the intertidal and surf zone are common, and ∼80% of the total number of species caught is considered as by-catch. The newborns and juvenile M. schmitti are an important element of this by-catch. Since the reproductive potential of the smoothhound shark is low, the protection of these newborns and juveniles from fishing pressure is of great importance.

This study evaluated the feeding habits of the franciscana dolphin (Pontoporia blainvillei) in south-eastern Brazil. Stomach contents were collected from a total of 145 dead specimens found incidentally caught by fishing vessels or stranded between 2005 and 2015. Fish otoliths, cephalopod beaks and whole non-digested prey were used for prey species identification. A total of 9337 prey items were identified, including 26 species of teleost fishes and three species of cephalopods. The most important prey families were Sciaenidae among fish and Loliginidae among cephalopods. Franciscana dolphins tended to feed on small fish (mean = 5.25 cm) and cephalopods (mean = 8.57 cm). The index of relative importance (IRI) showed that Pellona harroweri and Doryteuthis plei were the most important prey for both males and females. The PERMANOVA test confirmed that there is no significant difference between the feeding habits of different sexes, but detected a significant difference among seasons. Overall, our results show that franciscana dolphins are predominantly ichthyophagous and non-selective in relation to the type of prey, feeding on pelagic, demersal and pelagic-demersal prey.

The ommastrephid squid, Illex coindetii, is one of the most abundant cephalopods in the Mediterranean Sea and an important predator in the ecosystem. In the present study, we examined the diet habits of I. coindetii in the north-western Mediterranean Sea by combining two complementary approaches: stomach content and stable isotopic analyses. Specifically, we examined whether the diet differed between sizes and seasons. Stomach content results indicated that the diet of I. coindetii was composed of 35 prey items including four major groups; namely the crustaceans Pasiphaea sivado, Amphipods, squid of the Order Teuthida, and pelagic and mesopelagic fish. Differences were found among different ontogenetic sizes: juvenile individuals fed mainly on crustaceans (%IRI = 77.59), whereas adult individuals fed on a wider range of prey items, including the shrimp P. sivado (%IRI = 33.21), the amphipod Anchylomera blossevillei (%IRI = 0.91), the decapod Plesionika sp. (%IRI = 0.19), the carangid Trachurus trachurus (%IRI = 0.34) and some Myctophids species (%IRI = 0.21). Differences were also found between seasons in the year. In winter, crustaceans were the main prey items, whereas in summer the diversity of prey was higher, including fish, crustaceans and molluscs. Similar to the stomach contents, stable isotopic results indicated differences among sizes. δ15N values were higher in adult squids than in juveniles because they fed on prey at higher trophic levels. In conclusion, this study indicates that feeding habits of I. coindetii vary seasonally and ontogenetically. These feeding variations may be associated with trophic competence scenarios based on size, and also with the availability and abundance of prey throughout the year.

We examined the benthic fauna in four areas along a mangrove tidal channel in south-eastern Brazil, between October 2008 and August 2009. The tested hypothesis is that the most abundant groups avoid competition as they occupy different types of substrata and that the longitudinal distance from the sea also affects the occurrence of benthic fauna along the channel. We also examined the prop root epibiont fauna to describe this different community. Polychaeta was the dominant group in the sediment whereas Isopoda and Tanaidacea were the dominant groups on the prop roots. We found a tendency for higher infauna species richness and diversity in the innermost channel area during the summer. Higher abundance of epibiont fauna was also found in summer with tidal movements allowing the colonization of the prop roots of the mangrove forest by some taxa. The polychaetes Ceratocephale sp. and Laeonereis acuta had indication of habitat partitioning, with the first occurring mainly in very fine sand sediment whereas the latter preferred medium sand sediment. The microcrustaceans Chelorchestia darwini and Tanaidacea sp. 1 occurred in high abundance colonizing the prop roots. Exosphaeroma sp. was found in high abundance in infauna and epibiont fauna. The tested hypothesis of spatial partitioning of the mangrove channel by the benthic fauna was confirmed with the most abundant species occupying the substrata with different grain fractions and prop roots in different stations.

INTRODUCTION

Dodecaceria caulleryi breeds asexually by fragmentation and regeneration (schizogenesis), and sexually as an epitoke. Fragmentation is initiated in September-November in worms generally more than 40 segments long with the autotomy of the anterior 11–34 segments. Some 14–18 isolated segments are then autotomized in succession from the front of the remainder of the worm, leaving a residual 7–19 posterior segments. The anterior, individual segmental, and posterior fragments produced in this way all begin regenerating; anterior regeneration of the posterior fragment is limited to 14 or fewer segments but posterior regeneration and growth of all fragments is unlimited though slow. When the segmental fragment has regenerated about 7 new anterior and posterior segments, these may be autotomized as secondary individuals and the original segment regenerates again. The anterior regenerate is more commonly shed than the posterior regenerate and not all segmental individuals engage in secondary fragmentation.

Analyses of sea water collected during the years 1962–65 at International Hydrographic Station E. I are given here in the same form as in earlier reports. Temperature, salinity, nitrate, phosphate, and silicate were examined. Some values of suspended carbon and chlorophyll are also included.

Salinities were markedly higher in 1965 than in the previous 3 years. All 4 years showed a low value for maximum winter phosphate levels.

This study constitutes a preliminary assessment of the abundance and species richness of sponges living on the brown seaweed Sargassum spp. from the southern Gulf of California (Mexico). The diversity and abundance of sponges associated with Sargassum was investigated from November 2006 to November 2007. In addition, it was examined whether temporal variations in the abundance of associations were influenced by changes in size and density of Sargassum as well as environmental factors such as water temperature and salinity. Twelve sponge species (4 Haplosclerida, 3 Poecilosclerida, 4 Dictyoceratida and 1 Clathrinida) were found growing epiphytically on the lower portions of Sargassum plants and the most frequent species were Callyspongia californica and Haliclona turquoisia (38% and 27%, respectively). The abundance of associations showed significant temporal and spatial variations, being higher from June to November (post Sargassum growth period), at depths from 0.5–2.5 m. The number of sponge species m−2 (both epiphytic and non-epiphytic) inside the seaweed bed was 4.8 species m−2, while outside it, the absence of hard substrate for attachment severely restricted the number of sponges. These results suggest that Sargassum provide substratum and habitat for the sponge community from this region, and that their seasonal growth patterns may influence the abundance and diversity of the associations.

Pennatula phosphorea Linn, is a well-known luminescent animal, which was studied by that pioneer investigator, Panceri (1871,1872 a, b). He found that the animal luminesces when excited, and that the light emanates from the zooids. From the region stimulated luminous waves proceed, with measurable velocity, to the extremities of the animal. Since waves can be initiated in either direction, up or down the colony, it follows that the transmission system is non-polarized. Recent studies on other species of pennatulids have shown that luminescence is under control of a nerve net (Nicol, 1955 a, b, c; Daven-port & Nicol, 1956). Harvey's book on Bioluminescence (1952) gives a review of pertinent literature, plus a bibliography.

We examined the diet of pelagic juveniles of Trachurus japonicus in the surface layer in April, and subsequent demersal juveniles in the near bottom layer during May to June of the East China Sea (ECS) in 2005, 2008 and 2009. Diet composition of the pelagic juveniles showed a significant difference between 2005 and the other two years. That is, they preyed mainly on Paracalanus parvus s.l. and occasionally on Calanus sinicus in 2008 and 2009, while they fed mainly on Corycaeus affinis in 2005, partly corresponding with the between-year difference in prey densities. The demersal juveniles depended heavily on the fifth copepodites and females of C. sinicus which store lipids in the body, i.e. high-energy food for the juveniles, without a significant inter-annual difference. The markedly low occurrence of P. parvus s.l. and C. sinicus, which are considered to be energetically more favourable than C. affinis, from the stomach of the pelagic juveniles in 2005 corresponded with the lowest growth rates of the pelagic juveniles in the three years. Potentially, this resulted in the lowest observed recruitment level of the demersal juveniles for the ECS in 2005 over these three years.

The salinity preferences of the amphipods studied were found to correlate with distribution. Marinogammarus marinus, a marine species, showed a strong preference for higher salinity levels, the estuarine Gammarus duebeni showed little avoidance of any particular sea water concentration, and the freshwater Gammarus pulex displayed strong preference for dilute media

Tolerance experiments showed that the preference behaviour of M. marinus was not caused by lethal effects of salinity.

Observations on M. marinus suggested that the behaviour involved components of both preference and avoidance.

In M. marinus the choice is made on the basis of total osmolarity of the medium, not on its organic or ionic content alone.

Ablation of the upper and/or lower antennae had no effect on salinity choice in M. marinus, and acclimation to 50% sea water did not alter the preference for full sea water.

It is suggested that behavioural responses which confine animals to areas well within their physiological salinity limits promote survival in aquatic environments which may undergo fluctuations in salt concentration.

Descriptions of the polychaete Nephtys hombergii Savigny, 1818 have encompassed a wide range of apparently intraspecific variation in taxonomic features such as the segment on which interramal cirri first occur, and the form and size of pre- and postsetal lamellae (Fauchald, 1963; Woolf, 1968; Hartmann-Schröder, 1971). During the examination of museum collections and of extensive ecological collections from the North Sea (Rainer, 1990) and from Danish waters, it was found that the name N. hombergii has been applied to three morphologically similar species, viz. N. hombergii (s.s.), N. assimilis Örsted and N. kersivalensis Mclntosh. Both are locally abundant species that may occur with N. hombergii. This paper designates a neotype of N. assimilis, provides a full description of N. assimilis and N. kersivalensis, and removes these species from synonymy with N. hombergii.

If a male dogfish is held in the hand and its belly stroked firmly backwards with the ball of the thumb a fluid can be expressed from the cloaca. In my experience this fluid in a fresh animal invariably contains sperm, whatever the season of the year. After a period of inanition, however, sperm eventually disappears from the cloacal fluid. Such an animal is a convenient test object for gonadotropic activity by a method which closely parallels the toad-pregnancy test of Galli Mainini (1947).

A recent study by Fretter & Graham (1949) has shown that members of the family Pyramidellidae are ectoparasites, each species feeding on a particular host, usually a tubicolous polychaete or a lamellibranch, by piercing the body wall with the buccal stylet and sucking blood, and perhaps tissue debris, by means of the buccal pump. A list of hosts, each with its specific parasite, was given.

Subsequently, Cole (1951) recorded the presence in oysters of a species, Odostomia eulimoides Hanley, which had been observed by Fretter & Graham, and recorded previously by Jeffreys (1867), as feeding on Pecten maximus (Linné) and Chlamys opercularis (Linné). The Odostomia were lodged in small pockets inside the ventral margin of the shell of 2-year-old native brood oysters dredged from near Paglesham in the River Roach, Essex. The pockets were formed as a consequence of the withdrawal of the mantle in response to the irritation caused by the proboscis of the parasite during feeding.

The results of morphometric and developmental studies made to elucidate the relationship between Parathemisto gaudichaudi (Guerin) and P. gracilipes (Norman) show them to be one and the same species. Apparent differences are due to differences in the size of specimens at maturity, and to the degree of development of the bispinosa-compressa condition. P. gaudichaudi takes precedence over P. gracilipes.

The species is highly variable, existing in two extreme forms, the bispinosa form and the compressa form, together with all possible intermediates. The full range of the bispinosa-compressa condition is not expressed until a body-length of 10 mm is reached. Specimens are capable of changing towards either extreme at moults, but the factors causing the change are unknown.

A key to the genus Parathemisto Boeck is included.