The factors potentially leading to the development of periodic hypoxia were investigated based on field studies performed over a series of two years between November, 1997 and November, 1999. This was attempted by investigating both hard and soft seafloor. Descriptive and predictive models were developed that incorporated physical, chemical and biological data derived from the present study and previous work and were used to anticipate future possible crashes of the faunal communities due to hypoxia/anoxia. It was concluded that periodic hypoxia at Ardbear is a natural event caused by several factors to varying degrees. The results of the present study indicate that the major controlling factors for oxygen depletion are the shallow depth of the system, coupled with the development of thermal stratification during periods of calm ambient meteorological conditions of the warmer summer months. In addition, a soft, muddy bottom and highly productive plankton blooms exacerbate conditions in a system already predisposed to hypoxia.

Habitat fragmentation from natural or human-mediated causes is a common phenomenon in terrestrial and aquatic environments. In this study, the effects of varying the size of habitat patches on the abundance of benthic invertebrates inhabiting date mussel (Musculista senhousia) patches was studied at two different transition environments, the Goro Lagoon (Adriatic Sea) and the Padrongiano Delta (Tyrrhenian Sea). Benthic fauna responded to habitat patchiness in a complex manner that varied according to habitat type, taxon and animal body size (small: 0.5–2.0 mm; large >2 mm). Small invertebrates were mostly polychaetes, nemertea, amphipods and isopods. Large invertebrates were mostly large polychaetes, bivalves, gastropods and crabs. Invertebrate population size and diversity seemed to be maximized in landscapes that include both small and large patches of mussel beds ‘embedded’ in a continuous matrix. Musculista senhousia patches served as a critical refuge and foraging habitat for many species. Patchy and continuous areas may promote the persistence of organisms with different life histories, especially in environments like those studied where mussel patches represent the only structural refuge available.

A growing body of literature shows that benthic communities are hierarchically structured on spatial and temporal scales. In two study locations at Helgoland (North Sea), the northern and the western locations, we: (1) investigated the variation in abundance of specific algae and invertebrates at two spatial scales; and (2) evaluated the relationship between elevation and specific species at these scales. We were also interested in using this information about the spatial pattern of individual algae and invertebrates as well as the patterns of elevation to help develop a monitoring programme of the rocky intertidal. We examined the variation of individual algae and invertebrates by means of a hierarchical nested design. Data were taken from five replicates per plot, with plots located in transects (two transects per location).

At the northern location, the highest variability in cover of most algae and invertebrates occurred at the scale separated by about 50 m (scale: transect). This was a direct result of differences between the high- and the low-shore. Most species at high-shore showed a relatively low frequency of occurrence in contrast to a highest frequency of occurence (~100%) and maximal values of cover at low-shore. However, neither a linear nor a non-linear relationship between elevation and the specific species occurred. At the western location, the highest variability in most macroalgae and invertebrates investigated was among replicates (10s of centimetres apart). No relationship between elevation and individual species occurred at this location. Macroalgae at both locations were more consistent over time than invertebrate species. Our results suggest that the relevant processes shaping the individual macroalgae and invertebrates at the Helgoland rocky intertidal vary between locations and the specific species.

The potential causes of variation in macroalgal and invertebrate species at different spatial scales are discussed and suggestions for a future monitoring programme are given. Temporal inconsistency in the spatial patterns, and the fact that some individual algae and invertebrates comprising the benthic assemblages vary at different scales, speak in favour of a multiple-scale sampling approach for monitoring change in the intertidal communities at Helgoland.

We compared the reef fish assemblages of two habitats, coral reefs and coral communities (rocky substratum with coral colonies), in the Las Perlas Archipelago in Pacific Panama and attempted to determine associations with habitat variables. We used a modified Atlantic and Gulf Rapid Reef Assessment (AGRRA) survey to record fish species and quadrat transects to determine benthic composition. Multivariate non-parametric multi-dimensional scaling (MDS) ordinations were performed in PRIMER and univariate correlations were used to determine relationships. The reef fish of coral communities were significantly more diverse and species rich than those of coral reefs. The two habitats had significantly different species and size composition, but trophic and family groups overlapped between habitats. Topography, exposure, and the percentage cover of branching and massive corals correlated significantly with differences in fish parameters. The reef fish assemblages of this region appear to be determined more by the larger scale structural features that characterize the two habitats than by features that vary over small scales within the habitats.

Measurements of the release of dissolved organic nitrogen (DON) and carbon (DOC) were carried out on an axenic batch culture of the coccolithophorid Emiliania huxleyi. This unicellular marine alga was cultured using a media with nitrate as the sole N source and the changes of DOM concentrations measured over 14 days. Results showed that there was a significant release of DON, i.e.7.6 µM N day−1 during mid-exponential growth phase (days 5–7). The highest release of DOC was also recorded in the same growth phase and accounted for 24.0 μM C day−1.

A total of 327 yeast strains from seawater, sediments, mud of salterns, guts of the marine fish and marine algae were obtained. After crude protein of the yeasts was estimated by the method of Kjehldahl, we found that eight strains of the marine yeasts grown in the medium with 20 g l−1 glucose contained more than 30.4 g protein per 100 g of cell dry weight. The results of routine identification and molecular methods show that they belong to Metschnikowa reukaui, Cryptococcus aureus, Aureobasidium pullulan, Yarrowia lipolytica and Hanseniaspora uvarum, respectively. With the exception of Aureobasidium pullulans 4#2 with nucleic acid of 7.7% (w/w), all other yeast strains contained less than 5.0% (w/w) of nucleic acid. Analysis of fatty acids shows that all the yeast strains tested had a large amount of C18:0 and C18:1 fatty acids while analysis of amino acids indicates that the yeast strains tested had a large amount of essential amino acids, especially lysine and leucine which are very important nutritive components for marine animals.

In order to evaluate the environmental status within a mariculture pond, temporal variations of physico-chemical factors, protist community structure and interactions between biota and environmental conditions were investigated during a complete cycle in semi-enclosed shrimp-farming waters near Qingdao, north China. Results revealed that: (1) a total of 54 protist taxa with ten dominant species was present, comprising 4 chlorophyceans, 2 chrysophyceans, 5 cryptophyceans, 10 dinoflagellates, 3 euglenophyceans, 10 diatoms, 18 ciliates and 2 sarcodines; (2) a single peak of protist abundance occurred in October, mainly due to the chlorophyceans, diatoms and chrysophyceans, while the bimodal peaks of biomass in July and October were mainly due to the ciliates, dinoflagellates and diatoms; (3) the succession of protist communities significantly correlated with the changes of nutrients, salinity and temperature, especially phosphate, either alone or in combination with NO3; (4) species diversity and evenness indices were found to be relatively independent of physico-chemical factors, whereas species richness and the ratio of biomass to abundance were strongly correlated with water temperature and abundances of bacteria. It was concluded that planktonic protists are potentially useful bioindicators of water quality in a semi-enclosed mariculture system.

Two new species of polyclads are described from the continental slope of the Gulf of Mexico. Specimens of Didangia carneyi sp. nov. and Oligocladus bathymodiensis sp. nov. were collected from the Louisiana slope at 610 m and 650 m, respectively. Didangia carneyi sp. nov. was collected from a natural wood fall, and is characterized by the presence of tentacular and cerebral eyes, an interpolated prostatic vesicle provided with two muscular accessory prostatic vesicles, and large glandular cells that surround the male atrium. Oligocladus bathymodiensis sp. nov. has a mouth anterior to the brain, a few cerebral and pseudotentacular eyes, four pairs of intestinal branches, and a ventral anal pore. Specimens of this species were collected on the margin of a hypersaline cold seep in association with mussels of Bathymodiolus childressi. All type material is deposited at the Field Museum of Natural History, Chicago, Illinois, USA.

The family Monhysteridae is characterized by 17 valid genera, seven of which are known to be free-living, inhabiting marine sediments. In total, 70 valid marine species are ascribed to these seven genera. Overall, the family is characterized by a confused taxonomic history with a large list of synonyms and species inquirendae. The taxonomic problem is not restricted to the old literature, but inconsistencies also appeared in recent studies. The aim of this study is to show the most important diagnostic characters to identify each genus and provide taxonomic tools for species identification. Dichotomous-keys and illustration-guides are attempted for the marine monhysterid species. For the family and each subfamily, tribe and marine genus a brief historical background, diagnosis and a list of valid species is provided. Hereby, we propose to transfer eight species of the genus Thalassomonhystera to the genus Monhystrella.

In a study investigating the composition and spatial and temporal variation of the benthic macrofauna associated to the discharge of domestic sewage off Fortaleza, north-eastern Brazil, a new species of Syllis was found. This new species, S. guidae sp. nov., is characterized by having blades of falcigers with subdistal tooth about same length as distal tooth, but stouter than it, with spines on cutting edge almost reaching the tip of subdistal tooth, blades of falcigers with conspicuous subdistal triangular process and unusually long anal papilla between anal cirri, measuring about one-quarter of their length. Syllis guidae sp. nov., is herein described and compared with the most similar congeners.

Fatty-acid and energy content of Maja brachydactyla eggs at different developmental stages (recently spawned, half-developed and ready to hatch) were analysed in order to understand what is being consumed and produced during the embryonic development. Egg volume increased during development (34%, 0.187 to 0.285 mm3, N = 270) and was negatively correlated with egg energy and fatty-acid content (r = −0.80 and r = −0.46, respectively), which decreased through embryogenesis. The most consumed fatty acids were the PUFA (21.2 μg · mg dw−1), followed by the SFA (18.8 μg · mg dw−1) and MUFA (14.9 μg · mg dw−1). Palmitic (16:0), oleic (18:1n-9) and eicosapentaenoic (EPA, 20:5n-3) acids were preferentially consumed (13.14, 9.21 and 8.67 μg · mg dw−1, respectively). The fatty acid composition found in M. brachydactyla eggs reflected the habitat and omnivorous and detritivorous scanvenger diet of the adults, although the consumption of algae was more important than previously thought, at least in the area where these adults were captured. Pre-hatching eggs have a high PUFA content (64.5 μg · mg dw−1 or 46.3% of the egg fatty-acid content). We conclude that larvae of this species might need a diet rich in PUFA, particularly EPA and DHA, for successful development. From the culture perspective, live preys commonly used in aquaculture will likely require to be enriched with DHA.

Three species of Oncaeidae, Triconia umerus, T. hawii and T. rufa are reported for the first time in the coastal waters of the Gulf of Naples, Tyrrhenian Sea, western Mediterranean Sea. They were found in meso-zooplankton samples collected in 2004 and were absent from samples collected prior to 2004. Specimens of Triconia umerus and T. hawii were compared with material collected from the type locality (the Red Sea). In order to facilitate identification, brief differential diagnoses, supported by scanning electron micrographs, are presented for the five species of Triconia that have small body size (450 to 600 μm) and co-occur in the upper 50 m of the water column of the Gulf of Naples. Surface ornamentation on the genital double-somite of the female is reported in T. minuta and T. hawii for the first time, but it is difficult to observe using light microscopy and we infer that it has probably been overlooked in these species hitherto. Possible explanations for the new discovery of these species in such a well-studied area are discussed and it is suggested that they represent relatively recent additions to the fauna. A key to the eleven species of Oncaeidae found in the Gulf of Naples is presented.

Several crab species are important fishery resources in Brazil and their overexploitation has lead to severe population declines in some regions. The management of populations of these species should take into account the degree of gene flow among populations in different estuaries. The goal of the present study is to assess the degree of geographical structure in the genetic diversity of the blue land crab, Cardisoma guanhumi, along the Brazilian coast. A fragment of the control region of the mtDNA (750 bp) was sequenced for 95 specimens collected across 5 Brazilian states. Analyses using F-statistics failed to indicate any evidence of geographical structure, a result that was corroborated by a nested clade analysis of the same dataset. Mismatch distribution analyses indicated that populations of the blue land crab have experienced an expansion during their recent evolutionary past. The obtained results are similar to those recently described for another sympatric crab, Ucides cordatus, particularly with respect to the extensive degree of gene flow. However, populations of C. guanhumi seem to be older than those of U. cordatus and do not show the north–south expansion found in that species.

Melitid amphipods belonging to the Maera–Ceradocus-group are re-examined from the Atlantic coast using material from the collection in the Smithsonian Institution (Washington): Ruffomaera gen. nov. is established for Maera williamsi, furthermore Meximaera briani sp.nov., Maeropsis cf. perrieri and Ceradocus breweri (transferred from Gammarus) are described and illustrated.

The reproductive biology of Scyllarides deceptor was studied along the southern Brazilian coast (27°S 48°W) from December 2002 to December 2003. Samples were collected monthly at Xavier Island, where animals were caught and marked. Fecundity and egg size were estimated from ovigerous females caught also in two adjacent islands, Arvoredo and Aranhas. A total of 98 females was recorded at Xavier Island during the sampling period, 24 of these were recaptured and presented time-at-liberty ranging from 14 to 297 days. Ovigerous females were observed during spring and summer, with the moulting period lasting from late winter to spring. Size at sexual maturity was assessed from 66 females caught during the breeding season and estimated in 85.33 mm of carapace length (CL). Mean fecundity of S. deceptor was estimated in 191,262 eggs (±17,811, SE) for females, on average, 94.74 mm long (±1.86 mm SE) (CL). Fecundity was significantly related to CL (R2 = 0.90) Mean egg size was 0.67 mm (±0.005 mm SE) and did not correlate significantly to CL (P = 0.78). The rocky bottom of Xavier Island was favourable for reproduction, presenting shelter and foraging grounds for the ovigerous females. For management purposes, our results suggest the closure of the S. deceptor fishery from November to January and the capture-size of females to be restricted to animals larger than 90 mm (CL).

Investigating the spatio-temporal patterns of planktonic larvae is fundamental to studies regarding stock assessment and larval dispersal of commercial and non-commercial, i.e. invasive or rare marine invertebrates. Because of the difficulty involved in morphological identification of marine invertebrate larvae, various molecular methods based on PCR have been used to enhance taxonomic resolution. In previous studies, different methods for the preservation or pretreatment of larvae were applied in each case. However, no comparative studies have been conducted to determine the optimal method for PCR testing for bivalve larvae, and no information is available regarding the selection of an appropriate method.

This study compared the PCR success rate of 6 pretreatment methods for larvae of the Mediterranean blue mussel, which was preserved using different fixatives (70% ethanol, 100% ethanol, 70% acetone and 10% formalin). The results revealed that the success rate of PCR was different for each pretreatment; moreover, the use of ammonium sulphate and Tween 20 buffer with proteinase K digestion was found to be the most effective method. Some pretreatments showed lower success rates for long-fixed larvae than for short-fixed larvae for formalin-fixed larvae; however, the success rate of PCR amplification for ethanol-fixed larvae pretreated by this method did not decrease through 1-year fixation. In addition, this pretreatment showed a high success rate for different fixation periods. These findings suggest that the selection of the pretreatment method is critically important for successfully amplifying larval DNA and that the pretreatment involving the use of ammonium sulphate prior to PCR amplification enables the use of fixatives for preserving bivalve larvae. This method will be utilized in various field studies and molecular genetic studies.

Imposex, the development of male sexual organs in female gastropods, is mainly induced by organotin compounds used as biocides in antifouling paints. As part of our continued efforts to report the occurrence of imposex gastropods along the coast of mainland China, this study investigates the imposex prevalence in Mauritia arabica (Mesogastropod: Cypraeidae). A total of 529 adults were collected from 11 sites in south-eastern China between March 2001 and June 2005. Of these, 303 were females and 226 were males. Imposex is classified into six stages representing the sequence from the initial appearance of the seminal groove or small penis (S1) to the point when this duct blocks the pallial oviduct and aborted egg capsules appear (S6). All six stages of imposex were found in M. arabica with three different types (a, b and c) of expression in stages 1 and 3, two types (a and b) in stage 2, and one type in stages 4, 5, and 6. Imposex development was also measured by various indices such as the vas deferens sequence index (VDS), female penis length (FPL), percentage of affected females (%I), the relative penis length (RPL), and relative penis size (RPS—the cubed form of RPL). Imposex individuals were found in all 11 sites with %I ranged from 26% to 100%. Excluding the data from site 3 (with only one female and one male), VDS scores ranged from 1.05 to 4.07, with an average of 2.86, and the RPL ranged from 0.9 to 56.8. High correlations were observed among VDS, FPL, %I, RPL, and the RPS. Our findings suggest that M. arabica is an ideal bioindicator for organotin pollution along the south-eastern coast of China, and can be used in conjunction with the rock shell, Thais clavigera, a well-established bioindicator of tributyltin and triphenyltin contamination. To our knowledge, this is the first detailed report of imposex in M. arabica.

Deep-sea organisms are generally considered to be restricted to the great ocean depths, unable to enter shallower habitats except perhaps at the isothermic polar latitudes, due to physiological constraints, or more intense biotic interactions. Wood-boring bivalves of Xylophaga, however, are here shown to be exceptional. A clade, formally recognized by Turner in 2002, united by the derived characters of a complex mesoplax and a truncated excurrent siphon, papillose incurrent siphon with a longitudinal dorsal trough bordered by lappets, and often carrying white or glass-like granules, occurs at significantly shallower and warmer depths than do other species of the genus. Here, description of the new species X. multichela from 106 m depth off the Pacific coast of Guatemala illustrates the characters that unite the clade. Because wood-boring bivalves face intense competition and high levels of predation at depths of 2200 to 3250 m, they may not perceive biotic interactions at shallower depths to be dramatically more intense. In addition, members of this group are hypothesized to tolerate reduced oxygen availability, a requisite if animals are to occur in warm waters.

Sexual maturation and spawning was followed in one and two year old rope cultured mussels (Mytilus edulis) from April to December. Development of gonad and storage tissue was followed using descriptive categories from histology, and development of total soft tissue was followed using meat yield and condition index.

Both age groups were mature both during spring and autumn and had similar patterns of spawning and maturation. April and May were characterized by scattered spawning activity and accumulation of storage reserves at the same time, resulting in relative constant condition indices during this period. This was followed by ripening of the gonads and an increase in condition index that culminated in a spawning in late June. Parts of the population then entered a resting phase, while a part of the population underwent new maturation towards an autumn spawning in September. In December all the mussels had started the winter maturation.

Condition index and meat yield were higher throughout the season in the one year old mussels. This was probably due to the sum of several factors, including differences in specific feeding rates and biomass density, rather than spawning.

The present study is the first to compare the reproductive patterns over time of one and two year old mussels with reliable age determination, and provide information that there are no obvious differences in neither timing of gonad development nor spawning patterns between the age-classes.

Most neogastropod species exhibit masculinization of the female when subject to tributyltin (TBT) pollution (a process known as ‘imposex’). To date, the dog-whelk Nucella lapillus is seemingly unique in having a genetic deficiency (termed Dumpton syndrome or DS) that disrupts the development of normal male sex organs, its presence being readily recognizable by the underdevelopment, or non-development (aphally), of the penis, and incomplete formation (non-closure) of the vas deferens, causing a split prostate. In highly contaminated conditions, female carriers of DS can be identified by a lesser degree of masculinization (notably aphally): they escape sterilization caused by the advanced stages of imposex. To date, DS has only been reported in areas with high TBT pollution which induces sterilization of normal females (i.e. non DS-affected females). DS is now, for the first time, observed at some locations where present TBT levels are low and some normal females lack penis development. In such conditions it is not possible to discriminate normal from DS-affected females using aphally. As DS-affected females must be discarded from the calculation of the imposex bioindicators to monitor TBT pollution, indirect tools such as molecular probe are now needed to further survey those areas where DS and TBT pollution may interact as, for example, in south-west Brittany.