The assemblage and the temporal changes of benthic macrofauna inhabiting the Phyllochaetopterus socialis (Polychaeta: Chaetopteridae) aggregates were analysed during 2004 and May 2005 in the Mar del Plata harbour, Buenos Aires (Argentina). Species composition, abundance, richness and diversity were estimated from monthly or bimonthly samples obtained by SCUBA diving. Multivariate (MDS) and SIMPER analyses were applied to analyse the structure of benthic communities. In the mats, a total of 57 species (invertebrates and chordates) belonging to 11 phyla were associated to P. socialis: crustaceans and molluscs were the most abundant species and crustaceans and polychaetes were the most diverse groups (14 and 11 species richness, respectively). The mean abundance ranged from 79.67±57.47 ind/250 ml to 718.75 ind/250 ml (mean±SD). The amphipod Monocorophium insidiosum, the gastropod Anachis isabellei and the tanaidacean Leptognathia sp. were the most representative species in the mats. Richness and diversity in P. socialis aggregates were higher than in surrounding sediments. Results show significant differences among months in composition, abundance and feeding guilds of the macrofauna associated with the mats. The assemblage of benthic macrofauna with permanent and temporary organisms in P. socialis aggregates suggests the existence of microhabitats in the mats that provide substrate, refuges for predation and availability of food increasing richness and diversity. These results allow considering P. socialis as an autogenic ecosystem engineer in the Mar del Plata harbour.

The red whelk, Neptunea antiqua (Mollusca: Prosobranchia) is a dioecious prosobranch species with internal fertilization, and lecithotrophic larval development. Sexual dimorphism, sexual ratio, the size and age at sexual maturity, and the annual breeding and hatching periods of this subtidal neogastropod were investigated in the central western Irish Sea. Sexual dimorphism was evident as female whelks were larger in both length and weight. Subtle differences in shell morphology were also detected between the sexes. All samples taken together indicated an equal male to female sexual ratio for the studied population. Size and age at sexual maturity were noted to differ between sexes, occurring at 75–90 mm (shell length), or four to five years in males, and 95–110 mm, or six to nine years in females. Quantitative and qualitative techniques identified an annual spawning period between late spring and early summer. Egg masses containing between 14 and 84 egg capsules were observed attached to the dorsal surface of whelk shells in the succeeding months. An average fecundity of 63·78 juveniles was estimated per egg mass deposited. Juveniles were observed to hatch after 6–7 months in laboratory maintained aquaria, indicating a hatching period from October to January in the Irish Sea.

A number of species of ophiuroid are known to occur in dense clusters on the sea-bed. Aggregations of Ophiothrix fragilis (Abildgaard) have been recorded from the English Channel by Allen (1899), Vevers (1951, 1952), Barnes (1955), Ancellin (1957), Cabioch (1961, 1967, 1968), Holme (1966), Warner (1969, 1971), and by Allain (1974). Beds of the same species have been found in the Irish Sea by Jones (1951) and by Brun (1969), on the west coast of Ireland by Könnecker & Keegan (1973) and Keegan (1974), and on the west coast of Scotland, where it is widespread in sea lochs and elsewhere around the coast (McIntyre, 1956, and personal communication, 1975). Records of Ophiothrix fragilis from the North Sea have been summarized by Ursin (1960). In the Mediterranean, aggregations of Ophiothrix quinquemaculata (D.Ch.) have been described by Guille (1964, 1965) from off the south coast of France, and by Czihak (1959) from the Adriatic. Hurley (1959) gives underwater photographs of Ophiocomina bollonsi Farquhar from the Cook Strait, New Zealand. Further examples of aggregation in ophiuroids and other echinoderms are cited by Reese (1966), Mileykovskiy (1967) and by Warner (1978).

A new species of dorvilleid polychaete, Ophryotrocha cyclops, has been observed on the rocky seafloor underneath deep salmonid aquaculture sites on the south coast of Newfoundland, Canada. The distribution of these opportunistic worms is likely related to organic matter accumulation on the seafloor, and this species may have a role in remediation processes. To better understand the functional role of O. cyclops at aquaculture sites, it is important to know what they feed upon. Here, stable isotope analyses (δ13C, δ15N and δ34S) and trace element analyses were performed on dorvilleids and their potential food sources at three aquaculture sites. Stable isotope analyses revealed spatial and temporal variation in the isotopic carbon signature of O. cyclops, highlighting possible differences in the food sources of individual dorvilleids within and between sites. The isotopic composition of dorvilleids was closest to that of fish pellets; the presence of abundant lipid droplets in gut epithelial cells of O. cyclops suggests the assimilation of fish pellet-derived lipids. Trace element analysis indicated that O. cyclops does not concentrate the aquaculture tracers Zn or Cu to a large extent. However, concentrations of sulphur were high in O. cyclops compared with other sources. Taken together, results show that O. cyclops most likely consume both fish pellets and flocculent matter-associated bacteria. As such, they are involved in sulphur cycling and fish pellet degradation at aquaculture sites.

Deep-water suprabenthic species of Mysidacea were studied in the Catalan Sea (western Mediterranean). Twenty-one samples were taken at depths from 385 to 1859 m, using a Macer-Giroq type sledge. Sixteen mysid species have been collected. Boreomysis arctica was the commonest species and Parapseudomma calloplura, Paramblyops rostrata and Erythrops neapolitana were also notable for their high occurrence. The genus Dactylamblyops, Mysidella biscayensis and Pseudomma affine were recorded for the first time in the Mediterranean. The greatest total abundance of mysids was found over the middle slope. On the upper slope P. calloplura and E. neapolitana formed the dominant species, and deeper B. arctica dominated. Species richness and diversity (H’) declined with increasing depth. The decrease in H’ was attributable to the growing dominance of B. arctica over the middle and lower slopes. Swimming coefficients near the bottom showed intraspecific differences. In general, the species collected inhabit the water column between 0.1 and 0.5 m above the bottom. The bathypelagic species Eucopia hanseni had high swimming coefficients. Amongst the suprabenthic species, B. arctica showed the highest swimming coefficients, and rose from the near-bottom during night on the upper and middle slope stations.

Two new species belonging to the precious coral genus Corallium were collected during a series of exploratory cruises to the New England and Corner Rise Seamounts in 2003–2005. One red species, Corallium bathyrubrum sp. nov., and one white species, C. bayeri sp. nov., are described. Corallium bathyrubrum is the first red Corallium to be reported from the western Atlantic. An additional species, C. niobe Bayer, 1964 originally described from the Straits of Florida, was also collected and its description augmented.

A floristic study of the marine plants and algae at Luhuitou reef, Sanya Bay, Hainan Island, China, was conducted during the rainy (October 2008 and November 2010) and dry seasons (April 2009 and February 2012). Specimens were collected in the upper subtidal zone (from 0.5 to 3 m depth at low tide). A total of 156 taxa were collected, including 143 macrophyte species (90%), 12 blue–green algal species (10%), and the seagrass, Thalassia hemprichii. The most diverse group was the Rhodophyta (79 taxa or 55%), followed by the Chlorophyta (38 taxa or 25%) and then the Phaeophyceae (26 taxa or 20%). In the upper subtidal zone, macroalgae formed two types of communities: polydominant communities of turf-forming algae and monodominant and bidominant communities of foliose or fleshy algae. Seasonal changes occurred in the dominant species, which appear to be caused by periodic annual events of thalli detachment and subsequent community succession. In spite of heavy pollution from dissolved inorganic nitrogen and phosphorus in Sanya Bay, the subtidal flora has not undergone any dramatic changes in species numbers or composition and is similar to that of unpolluted regions in the Indo-Pacific.

The disappearance of mercury from stored sea-water solutions of mercuric chloride has been studied by means of the chloroform-dithizone procedure and by the use of radioactive mercury (203Hg).

When sea water is enriched with nutrients facilitating the growth of bacteria, the rate at which mercury is lost from the solution is markedly increased. On the other hand, when the sea water is treated in various ways which prevent the development of bacteria, the loss of mercury from solution is considerably reduced.

Rates of loss of mercury measured by the chloroform-dithizone procedure and by the use of tracer isotopes are in good agreement only in the early stages of the experiments. Thus, at a time when approximately hah0 the mercury has been lost, titrations with chloroform-dithizone only account for about 50% of the mercury determined by measurements of radioactivity. Further findings have suggested that this discrepancy arises from the fact that a considerable amount of the mercury is taken up by bacteria and converted into a form which is not detectable with chloroform-dithizone.

Algal productive rates have rarely been estimated at sea, although many estimates have been made of primary productivity as g carbon/m2/day. A distinction may be drawn between productive rate and productivity, and it is in the use of the term ‘standing stock’. The latter is the quantity of living algal material per unit volume or beneath unit surface. The productive rate is the rate at which the standing stock reproduces itself; for a given species it is of course a division rate. It is expedient to use the term ‘division rate’ for a single species, but the term ‘productive rate’ may be used for the whole algal community. The productivity is the product of standing stock and productive rate and so contains in it the very great variations of standing stock that are the common experience of all planktologists.

The diet of all chaetognath species found in a broad pelagic area of the eastern Mediterranean was investigated through gut content analysis. Eight chaetognath species were recovered from four depth intervals between 0 to 300 m in the Ionian, Cretan and Rhodes Seas and in the Cretan Passage. The mean food containing ratio (FCR) value for all chaetognaths combined was 0·048. Copepods comprised nearly 65% of the total food items consumed. The epipelagic species Sagitta enflata, Sagitta serratodentata atlantica, Sagitta bipunctata and Sagitta minima fed mainly in the 0 to 50 m surface layer, while the mesopelagic species Sagitta lyra, Sagitta decipiens, Sagitta hexaptera and Krohnitta subtilis fed in deeper layers. Sagitta s. atlantica showed the highest mean FCR in the integrated water column (0 to 300 m) of the whole sampling area. The estimated impact of chaetognath predation on copepod communities ranged from 0·3 to 7·8% of the copepod standing stock, and was higher in the Ionian Sea and the Cretan Passage than in the Cretan and Rhodes Seas. Sagitta s. atlantica, S. lyra, and S. decipiens had the most important predation impact among the eight chaetognath species found in the 0 to 50 m, 50 to 100 m and 100 to 300 m depth layers respectively.

Eulalia viridis (L.) is one of a group of polychaete species which are being used in an experimental analysis of the regulation of gametogenesis and reproduction. The back-ground to these studies and some of the preliminary results have been discussed recently by Olive (1980). Despite the abundant data demonstrating the frequent occurrence of well-defined reproductive cycles in marine invertebrates and observations on the correlations between reproductive events and environmental conditions, the mechanisms by which the reproductive cycles of individual species are controlled are very poorly understood. It has generally been accepted since the publication of the important paper of Orton (1920) that the temperature cycle in temperate and boreal regions plays an important role in determining the reproductive cycle, but the nature of the control mechanism is not, in general, understood and is likely to vary markedly between species. Environ-mental conditions such as relative daylength or biological factors such as the quantity and identity of the phytoplankton organisms (Himmelman, 1978, 1979) could also play important roles in regulating the sequence of cellular events which culminates in successful reproduction. These general problems have been discussed by Giese (1959) and more recently by Barnes (1975), Giese & Pearse (1975) and specifically in relation to Polychaeta by Clark (1979) and Olive (1980).

The qualitative and quantitative monthly composition and the annual temporal changes in a shallow (3·3–6·3 m) community of Crustacea: Decapoda associated with soft bottoms (very fine–muddy sand) and the seaweed Caulerpa prolifera in the south of Spain (Valdelagrana Beach in the Bay of Cadiz) has been studied for two years from February 1994 to January 1996. This community showed a similar pattern in both analysed cycles and could be characterized by a change or succession in the abundances of two groups of species: in autumn–winter Hippolyte inermis and Hippolyte varians (species associated with seaweeds); and in spring–summer: Philocheras monacanthus, Diogenes pugilator (characteristic of sandy bottoms) and Macropodia parva. The results of the ordination analysis of monthly samples is related to the absence or abundance of these dominant species although it does not define the two seasonal groups. The analysis of monthly richness, equitability, diversity and k-dominance curves, during the two years, showed a stable and rich community (with more than 6100 specimens caught belonging to 49 species) despite the human influence and the proximity of the Guadalete River.

This communication reports on experiments, which studied the variation in competitive performance of juvenile cod (Gadus morhua L.) and their growth rates. The fish were held in groups of five in either summer or winter conditions and tested for their individual response to prey offered sequentially. There was marked individual variability. Fish that took the highest share of prey tended also to be those that took prey earlier than others. In winter conditions these fish were the largest, but in summer conditions size had no effect. There was a positive influence of the indices of competitive performance on individual growth rate but the relationship was not significant

The life history and reproductive biology of the gammaridean amphipod Melita palmata was studied in the Mar Chiquita coastal lagoon (Argentina). The animals were collected fortnightly or monthly from Ficopomatus enigmaticus reefs from December 2000 to March 2002. The population density reached a maximum of 1556.67±1560 ind/m3 (mean±SD) in March 2001, decreased dramatically after intense rainfalls in winter 2001, and had a minimum value of 141.67±27.54 ind/m3 (mean±SD) in March 2002. Size differed significantly between sexes. The maximum size of males was 11.5 mm and this was 1.4 times longer than the length of females. The average sex ratio (0.44) did not differ significantly from an expected 1:1 value. Ovigerous females were present from December to March, when the temperature was above 18°C. The body size of ovigerous females ranged from 2.9 to 6.81 mm. There was a positive correlation between the brood size and body length of ovigerous females, and the maximum number of eggs per female was ten. Recruitment took place during the whole breeding season; juveniles recruited at the beginning of the season matured at the end of the same season, those recruited late would probably reach maturity in the following season.

Stafford (1913) rejected the view of many early workers (see Ryder, 1883, 1884; Huxley, 1883; Horst, 1886) that oyster larvae cemented themselves to the substratum with secretions of the mantle edge. He thought that the mantle margin could not be extended sufficiently to form the extensive area of cement that he found on the left valve of cemented larvae. Furthermore, he argued that the mantle could not secrete so much material in the short period that larvae took to cement. He deduced from the much reduced state of the ‘byssus gland’ in settled larvae that this gland was the source of the cement and suggested that the cement was spread over the shell by the foot. Nelson (1924), Prytherch (1934), Cole & Knight-Jones (1939) and Cranfield (19736, c) have clarified the role of the foot in cementing. Nelson (1924) also noted that cementing oyster larvae extended the mantle margin over the substratum but considered that this action spread the cement discharged by the foot and that the folds themselves did not secrete more material. The other authors, like Stafford, have dismissed or ignored any part the mantle folds might play in cementing.

One hundred and four specimens of Branchiomma luctuosum (Grube, 1870), a sabellid polychaete, were submitted to different anaesthetization and fixation procedures: a control group with living animals, immediate fixation with formaldehyde 4% (FO), ethanol 100% (AE) or ethanol 70% (ET), and anaesthetization with magnesium chloride (MC), refrigeration (RE), menthol crystals (ME) or freshwater (FW). Twenty-three morphometric variables of the body were measured and analysed with size-free multivariate statistics. The first three canonical variables explained 80% of the variation, being significantly correlated with 19 measured variables, mainly those related to the shape of the body setigers. Besides morphometric variables, some morphological characters commonly used in polychaete taxonomy also presented variation among fixation procedures, such as the release of parapodial elements and the integument. Among the procedures tested, AE, ET and FW were the best in approximating the shape of living specimens. Specimens submitted to FO and RE had shorter, wider, and thicker bodies, whereas those submitted to MC and ME were more elongated, narrower, flatter, and had wider pygidia than living specimens. Lengths of branchial crown, setiger 1 and pygidium seem to be the most informative morphometric characters for taxonomic purposes since they did not present deformation due to fixation procedures.

With this note we contribute to the discussion on the appropriate level of taxonomic resolution required in benthic monitoring studies. In a set of multivariate analyses using data from different taxonomic levels and various data transformations we show that similar results are obtained on the levels of species to families, almost irrespective of the transformation used. For taxonomic levels above that of orders, transformation results in different plots and especially presence/absence transformation reduces the discrimination of sites. We recommend guiding the choice of transformation by biological considerations and adjusting the taxonomic sufficiency to the objective of each study.

The discovery of a new species of Sarsia hydroid and its medusa and a comparison of this species with Sarsia tubulosa (M. Sars) and S. loveni (M. Sars) have resolved a longstanding problem. In his detailed account of the hydroid and medusa Coryne mirabilis (now accepted as identical and synonymous with Sarsia tubulosa), Louis Agassiz (1860-2, vol. 4, pp. 189-90, 203-4, P's- 17J i8) asserted that it undergoes a change of reproduction in winter and spring. He stated that in late winter the hydroid releases medusae but that in spring the gonophores no longer develop into normal medusae, being retained on the hydranths where they become sexually mature without mouth and tentacles. He based his conclusions on a series of hydroid colonies collected on the shore. Allman (1871-2, pp. 278-9) was strongly disinclined to accept Agassiz's assertion of the specific identity of the two forms of gonophore without stronger evidence, saying that, until the two kinds were found simultaneously or in succession on one colony kept under close observation in an aquarium, the identity of the two forms could not be accepted as proved. Mayer (1910, p. 55), from personal observation of colonies collected on the coast of Massachusetts, came to the same conclusion as Agassiz, but he did not say whether he had followed the succession in an aquarium or had observed one colony throughout, and accordingly his conclusion is subject to the same criticism.

The diagnostic features of the Ponto-Caspian gobiid genus Knipowitschia Iljin, 1927 and related European genera are summarized with reference to the cephalic lateral-line system. The Adriatic Gobius panizzae Verga, 1841 is now shown to belong to Knipowitschia, and a second species, K. caucasica (Kawrajsky, in Berg, 1916), widespread in the Ponto-Caspian region, is recorded from the northern Adriatic (Gulf of Venice). The occurrence of these species in the Adriatic Sea is explained by Quaternary changes in union between the Mediterranean and Black Sea, with K. panizzae derived from Black Sea Knipowitschia stock emigrating via a temporary Riss/Würm interglacial confluence, and the K. caucasica of very recent origin through the existing postglacial connexion. A redescription of K. panizzae, based on syntypes and more recent material, is provided in an Appendix.

The local population of common bottlenose dolphin in the Balearic Islands coastal waters, a mass tourism destination in the western Mediterranean subject to increasing anthropogenic pressures, was monitored over a three-year period. Photo-identification surveys provided a relatively small population estimate, even though the islands are considered to be a hotspot for the species in the Mediterranean. Dolphins showed strong site-fidelity and relatively limited mobility across the archipelago, which makes them highly dependent on waters which are severely affected by overfishing, habitat degradation and boat disturbance resulting from a continuously-growing tourism and shipping industry. Ecosystem-based management actions are urgently needed to ensure the conservation of this fragile population of bottlenose dolphins. Conservation measures should be developed within the already-existing political and legal marine biodiversity conservation framework and in collaboration with local authorities and stakeholders.