Benthic macroinvertebrates were sampled seasonally in the subtidal and upper and lower swash zones at two sites in each of six nearshore habitat types on the lower west coast of Australia. The habitat types, which differed mainly in the extent of their exposure to wave activity and whether sea grass and/or nearshore reefs were present, had been distinguished quantitatively using values for a suite of seven statistically-selected enduring environmental characteristics (Valesini et al., 2003). The core samples yielded 121 species representing eight phyla, among which the Polychaeta, Malacostraca and Bivalvia were the most speciose classes, contributing ∼38, 23 and 10%, respectively, to the total number of individuals. The total number of species and mean density of macroinvertebrates at the most protected habitat type (1), i.e. 70 and 209·2 individuals 0·1 m−2, respectively, were far greater than in any other habitat type. Habitat type influenced species composition to a greater extent than either zone or season. Furthermore, the extents of the differences among the species compositions of the six habitat types statistically matched the extents of the differences among the values for the suite of enduring environmental characteristics that distinguished each of those habitat types. Overall, the species composition at habitat type 1 was the most distinct, containing five abundant species of polychaetes that were adapted to deposit-feeding in calm waters with high levels of organic material and which were rare in all other habitat types. In contrast, the fauna at the most exposed habitat type was characterized by four crustacean species and a species of bivalve and polychaete, whose mobility and tough external surface facilitated their survival and feeding in turbulent waters. The zonal differences in faunal compositions among habitat types were greatest in the case of the subtidal zone. The faunal compositions differed among zones and seasons only at the most protected habitat type.

A quantitative study of macrobenthos was carried out on three transects on the shelf and continental slope off Chile (22° to 42°S; from 100 to 2000 m water depth) within and beneath the oxygen minimum zone (OMZ). Macrobenthos mean densities ranged from 104 to 13 808 ind m−2, with highest values off Concepción (∼36°S), where highest chloroplastic pigment equivalents were also measured. Polychaetes were the numerically dominant group in all transects and depths, followed by peracarid crustaceans. Species richness and diversity correlated with observed changes in bottom-water oxygen concentrations and sediment-bound pigments. Our results show that the shelf macrobenthic communities were negatively affected by low oxygen. The non-metric multidimensional scaling (nMDS) analysis evidenced depth-related station groups which may be related to the different environments provided by the water masses involved. Indeed, the depth ranges of stations groups with their specific species inventories coincide quite well with the boundaries of the three important water masses in the region, the Equatorial Subsurface Water (∼50 m to ∼400 m depth), the Antarctic Intermediate Water (∼400 to ∼1200 m depth), and the Pacific Deep Water (>1200 m depth).

Fish assemblages associated with shallow (4–7 m deep) artificial rocky habitats (i.e. breakwaters) have been assessed between July 2002 and September 2003, at the marine protected area of Miramare and adjacent areas outside the reserve (northern Adriatic sea). Our purpose was to: (1) detect possible differences between ‘protected vs fished’ breakwaters; and (2) compare two visual-census techniques for fish assessment (i.e. strip transects vs stationary points). The fish assemblages observed between protected and fished breakwaters during all four sampling periods were statistically different. More fish taxa were found at the protected than fished breakwaters, while there was no difference in total fish density. Most fish species targeted by fisheries had a greater density (e.g. Sciaena umbra, Dicentrarchus labrax, Sparus aurata, Diplodus vulgaris, Diplodus sargus and Diplodus puntazzo) and/or size (e.g. S. aurata and D. annularis) at the protected than fished breakwaters. There was a significant difference in fish assemblages due to assessment method. In general, the number of taxa was greater when assessed by strip transects than stationary points. Total fish density was almost unaffected by the method used, while total density of demersal fish (i.e. excluding schooling species) tended to be greater when evaluated by strip transects, although the difference was statistically significant only in one sampling period out of four. These results indicate that protection from fishing may have the potential to influence fish assemblages associated with breakwaters. Additionally, caution should be used when comparing fish assemblage data collected by different visual assessment techniques.

The organismic assemblage associated with Caretta caretta was studied in 37 loggerhead turtles, washed ashore dead at various localities in the northern Aegean Sea. A total number of 63 macrobenthic species and 17 species of macroalgae were identified. From these species, 41 and 13 respectively are reported for the first time as epibionts of this turtle. Analysis of the epibiont species distribution on six loggerhead turtles gave some evidence regarding the settlement preferences of certain epibiont species. From a biogeographical point of view, 61·3% of the epibiont species were cosmopolitan, 30·7% had an Atlanto-Mediterranean distribution, while 8% were Mediterranean endemics.

The Purbeck Marine Wildlife Reserve lies within the boundary of the Dorset and East Devon World Heritage Site on the south coast. This study investigated the influence of visitors on intertidal biodiversity at Kimmeridge Bay, the only accessible part of the reserve. The assemblages present on two rock ledges were compared: Washing Ledge, which is regularly visited and utilized by people, and Yellow Ledge, which is more isolated and visited much less regularly. At each ledge, three habitat types were investigated: open rock, rockpools and the fucoid zone. Multivariate statistical analysis revealed significant differences in assemblages between ledges and among habitat types. The differences observed in the communities of the two ledges can be explained to some extent by natural ecological processes, but human impacts were also detected. The most obvious contrast associated with trampling was a reduction in the larger, branching species of algae and an increase in ephemeral and crustose species in the more heavily utilized areas.

Several bacteria have been isolated from different tropical ecosystems (tropical rain forest, seawater, and marine sediments) from the island of Puerto Rico. These microorganisms were screened for carbohydrase activity using chromogenic substrates (amylose, pullulan, cellulose, dextran, arabinan, galactomannan, and xylan). The results indicate that 2–9% of cultured organisms show carbohydrase activity. Isolates were identified by partial sequence analysis of the polymerase chain reaction amplified small subunit rRNA gene. GenBank database comparison of the most versatile strains gave a match with Bacillus sp., Staphylococcus sp., Halomonas sp., and a gamma proteobacterium. Growth curves indicate that all strains assayed can grow as well in at least one complex carbohydrate as in glucose. A high β-xylosidase activity was detected in the Bacillus sp. strain crude enzyme preparation and this activity seems to be almost entirely cell associated. Our results show that tropical environments can be potentially good sources of bacteria with novel carbohydrases.

The toxic dinoflagellate Alexandrium tamarense was studied along with surrounding oceanographic parameters from May 1998 to May 1999 in Scapa Flow, Orkney. Nutrient concentrations were higher in winter and showed a phase of depletion in late spring and summer. Dinoflagellates tended to be abundant in late spring and summer. Alexandrium tamarense was detected in the water column almost year round, with the exception of the winter months (September to December). The growth of the A. tamarense population in Scapa Flow was not reflected in a monospecific bloom but rather in moderate to small biomass levels and always in co-occurrence with other species of diatoms and dinoflagellates. The highest concentration recorded was 1600 cells l−1 but concentrations of 200–400 cells l−1 were more typical. The oceanographic parameters indicate that the occurrences of vegetative cells of A. tamarense seem to be explained in part by instability of the water column, low temperature and low nutrient concentrations.

Benthic microalgal communities usually make a major contribution to the primary production of estuaries and shallow seas. Pulse amplitude modulation (PAM) fluorometry was used to investigate the contribution of benthic microalgae to the primary production of the Okhotsk Sea coast and Saroma Ko Lagoon in northern Hokkaido. In general the benthic communities had a relatively high biomass but low photosynthetic activity. This led to estimates of 29·2% and 64·5% for the benthic contributions for the 9 m and 3 m depth sites at Mombetsu and 13·1% for Saroma Ko. Sea ice algae provided the greatest contribution at Saroma Ko.

A new species of the cosmopolitan genus Eudendrium, E. klausi, is described from Carrie Bow Cay, Belize. The species is characterized by a small colony with an intense blue colour, polyps armoured with large microbasic euryteles scattered on the hydranth body, hypostome, and female spadix; female gonophores on normal hydranths with a reduced number of tentacles. The new species is compared to other Eudendrium with similar cnidome, and other Caribbean species, including those described by Allman (1877). Among the latter, E. gracile, E. laxum, E. attenuatum, and E. tenellum (sensu Allman) are considered as species inquirenda due to the lack or the unsuitability of the type materials and the inconclusive original descriptions. Eudendrium exiguum, E. eximium, and E. fruticosum were also studied and demonstrated to be different from E. klausi sp. nov.

The trophic ecology and seasonal changes in the diet of the intertidal hydrozoan Tubularia crocea were studied analysing the enteron contents of hydranths collected each season of the year. The relationship between feeding rate, prey availability, and re-suspension processes caused by tidal currents was also assessed. The most prevalent food items were diatoms and crustaceans. The most remarkable differences occurred during summer, when crustaceans were more abundant than diatoms. Conversely, diatoms were the most abundant prey during other seasons, and they were almost the only prey found during winter. There was no relationship between abundances of primary prey items in the water column and their occurrences in stomach contents. Instead, most prey items consisted of benthic organisms, primarily two species of diatoms (Grammatophora marina and Licmophora abreviatta) and fragments (usually appendages) of the amphipods Caprella sp. and Jassa falcata. Most food items were digested within 4–4·5 hours. The mean number of items captured per polyp per day was determined to be 115·2±19·2 in summer, 93·6±14·4 in autumn, 76·8±21·6 in winter and 199·2±31·2 in spring. Prey biomass (dry weight) polyp−1 d−1 was 5·1 μg in summer, 2·3 μg in autumn, 1·8 μg in winter, and 6·3 μg in spring. These values, in relation to hydranth biomass (55·3 μg; dry weight), were equivalent to a food intake polyp−1 d−1 of 9·3%, 4·2%, 3·2% and 11·5% of its own weight, respectively.

A total of ten specimens of Pseudonereis anomala (Polychaeta: Nereididae) were collected on the shallow water hard substratum (0·2 m) at four stations located in the inner part of Izmir Bay (Aegean Sea, eastern Mediterranean) in January 2004. The absence of this species among the material collected previously at the same stations might suggest that it has recently become established in the area. A re-description of the species together with its ecological, reproductive, feeding and distributional aspects are provided.

Patches of a very dense tube mat biotope were found during fish habitat studies in the eastern English Channel. At three locations in the lows between linear sand banks off the French coast an un-described small Chaetopterus sp. occurred with small Lanice conchilega as an enriched sediment stabilizing biotope. This biotope was distinct though having similarities to other tide swept sub-tidal biotopes dominated by L. conchilega. Using cameras and side-scan sonar it was seen to overlay heterogeneous cobbles and shell hash with intermittent rippled sand veneer. The patchiness of this enriching biogenic feature contributed to the variability in trawl catches of fish.

Identification of the range boundaries and microgeographic distribution of cryptic species is greatly facilitated by the use of genetic markers. Here we characterize the geographic range overlap between two cryptic species, Chthamalus fissus and C. dalli, and show that as with other barnacle species, their distribution and abundance is probably dictated more by microhabitat characteristics and the presence of conspecifics than broader environmental gradients. We also show that C. dalli appears to be panmictic across the studied range.

This study was carried out to determine the amphipod fauna in Mar Piccolo, Mar Grande and the Gulf of Taranto. Material in this study was obtained from 96 stations at different depths (maximum depth: −50 m) using various methods depending on the substrata. A total of 65 species was determined and 25 species are new records in the seas of Taranto. Microdeutopus gryllotalpa, Ericthonius brasiliensis, Monocorophium insidiosum, Elasmopus rapax, Gammarus aequicauda, Gammarus insensibilis, Leucothoe spinicarpa, Lysianassa costae and Pseudoprotella phasma were the dominant species and have been found in all areas considered. The comparison of the data shows that the area examined presents a high difference regarding biocenotic index. The highest number of species was collected in the Gulf with 1944 individuals, belonging to 58 species and 19 families, followed by Mar Grande with 1448 individuals belonging to 36 species and 11 families; finally Mar Piccolo with 698 individuals, 12 species and 6 families, in the First Inlet and 546 individuals, 18 species and 6 families, in the Second Inlet.

The two zoeal and the megalopal stages of Petrolisthes robsonae, are described and illustrated from laboratory-reared larvae. Larval features are compared with those previously described for other species of Petrolisthes in the eastern Pacific. Larvae of P. robsonae exhibit similar but not identical features to those seen in other Petrolisthes species. A number of similarities are found with P. zacae while main differences are found with P. granulosus,P. platymerus and P. laevigatus. Differences with these species are related to the setation of maxilla and maxillule and the rows of denticles in carapace spines.

During studies performed on the ecological conditions of Izmir Bay and its biota, a population of Fulvia fragilis was observed to have recently colonized the bay. In this study, some comments are provided on the anatomical, ecological, taxonomical and distributional aspects of the species, which was first encountered during late 2001 in Izmir Bay.

The bivalvia species of the Dardanelles were investigated at the upper infralittoral zone, by diving and dredge. Various species belonging to 14 families were identified in the Dardanelles. The families are as follows: Mytilidae, Ostreidae, Cardiidae, Pimidae, Solenidae, Pectinidae, Arcidae, Nuculidae, Veneridae, Donacidae, Tellinidae, Anomidae, Scrobiculariidae and Gastrochaenidae.

Cytotoxic activity of the mollusc Mytilus galloprovincialis haemolymph was considered as a possible marker of mussel health status. An easy-to-use and low-cost cytotoxicity test was set up to assess whether cytotoxicity is influenced by environmental stress such as an increase in water temperature or a reduction in water pH or salinity. Experiments demonstrated that, despite great variability in cytotoxic activity among the mussel populations, changes in the water physical conditions reduce mussel cytotoxicity, making animals more vulnerable to pathogen aggression.

The rainbow pearl oyster Pteria sterna is distributed along the Mexican Pacific coasts and Gulf of Baja California, where it represents a great economic potential. Five sampled populations collected in Baja California were used to screen two mitochondrial DNA genes that have proven useful in population genetics studies of several other bivalve species. The lack of polymorphism detected in these samples suggests a recent event of very low population size, most likely a founder event, which is congruent with the absence of P. sterna in the fossil records in Baja California.

The reproductive cycle of the purple clam (Amiantis purpurata) northern Patagonian population was studied throughout a 19-month period (September 1993–March 1995) using standard histological techniques and quantitative indicators (oocyte diameter distributions, oocytes per ocular field and relative oocyte area). In this species gametogenesis is a continuous process involving a complete gonadal restitution after the end of the reproductive season (no resting period). The proliferation phase occurs during the coldest half of the year (April to September) and maturation takes place during spring (September to December). Several partial emissions of gametes, with subsequent restitution of the gametogenic series, occur during the summer months. During the total maturation stage, oocytes never filled the whole alveolar area: maximum per cent of alveolar sections occupied by oocytes (46%) was observed in late spring–early summer. Implications of the reproductive pattern in the context of palaeogeographic history of northern Patagonia, and the isolation of this population are discussed.