This study focuses on the synchronous blooms of the coccolithophore Emiliania huxleyi and three dinoflagellates Prorocentrum micans, Ceratium furca var. furca and Ceratium fusus var. seta observed between 7 June and 11 July 2003 in the Dardanelles. An analysis of the vertical distribution of the E. huxleyi population size with respect to various environmental parameters was discussed. Additionally, inorganic nutrients and phytoplankton interactions were investigated in relation to the bloom conditions and hydrography of the Dardanelles. The algal bloom started in nearby Izmit Bay (eastern end of the Sea of Marmara) in early June, then quickly spread through the Sea of Marmara and continued until mid-July. Thermal stratification was observed between different water masses at the time of sampling. During the bloom period, cell density of E. huxleyi ranged from 3.58 × 107 to 2.55 × 108 cells l−1 in the superficial layer. Prorocentrum micans was the second most-abundant species and the cell numbers ranged from 1.0 × 106 cells l−1 to 3.3 × 106 cells l−1. Other abundant species in this area included C. furca var. furca and C. fusus var. seta.

Decapoda taken in Continuous Plankton Recorder (CPR) samples from the Pacific in 1997 and 2000–2003 have been identified and measured. Some previously un-described larval stages were referred to species and characteristics of these are described. Distributions and seasonal occurrence of decapod taxa in the samples are described and discussed with particular emphasis on the dendrobranchiate shrimp Sergestes similis and the brachyurans Cancer spp. and Chionoecetes spp. There is a prolonged larval season at low levels of abundance off the Californian coast but in the more northern waters there is a shorter productive period but numbers of larvae per sample are high, particularly in June. Larvae of Chionoecetes and other Oregoninae were found only from May to July.

The aim of this study was to analyse the tolerance of the planktonic stages of Psammechinus miliaris to hydrostatic pressure and temperature. Embryos of Psammechinus miliaris were subjected to different combinations of pressure and temperature for 3, 6 and 12 h. The percentage of embryos at each stage and the percentage of embryos developing abnormally were measured. Larvae at the gastrula and prism stages were subjected to pressure and temperature combinations for 24 h and the larval survival was calculated measuring the percentage of swimming larvae. Both embryos and larvae could survive at greater pressures than the known adult depth limits. Larvae showed a much greater potential than embryos for surviving deeper, with approximately 100% of both gastrulae and prisms surviving up to 200 atm at 5°C. These results are similar to other shallow-water species of Echinoida. Thus larval tolerance of high pressure and low temperature may have been important for the success of this group in colonizing the deep-sea.

Following the accident of the oil tanker ‘Prestige’, we surveyed the large scale fuel deposition patterns on the Cantabrian shore (northern Spain) covering three regions (from west to east): (i) Asturias, west of Cape Peñas (24 segments surveyed); (ii) Asturias, east of Cape Peñas (33 segments surveyed); and (iii) Cantabria (also east of Cape Peñas, 256 segments surveyed). Fuel arrived to the Cantabrian Coast as a single oil wave which was more intense to the east than to the west of Cape Peñas. The mean percentage of coast length affected was 25, 41 and 15% in western Asturias, eastern Asturias and Cantabria, respectively. However, less than 10% of the substrate was covered by fuel in oiled patches, thus the impact was moderate. We conclude that these patterns are consistent with fuel transport by the Iberian Poleward Current, a hydrographic feature typical of this region during winter.

All habitats are modified to some extent by the species that live within them. Kelp is known to have a very strong influence on the surrounding environment providing a habitat for a wide range of organisms including marine mammals, fish and invertebrates. Here we examine the consequences of a subtle shift in the relative abundance of two species of kelp, Laminaria digitata and Laminaria ochroleuca, and compare the holdfast epibiont assemblages on both. These species are morphologically very similar and both provide important biologically generated habitats. The distribution of these kelp species is predicted to alter as a consequence of climate change with L. ochroleuca extending its range northward and potentially outcompeting L. digitata in the north-eastern Atlantic. The epibiont fauna common to both species of kelp were predominantly made up of annelids, molluscs and bryozoans. Most of the epibiont flora we found on the holdfasts was from the class Rhodophyceae. Multivariate analysis showed that the richness of epibiont species associated with L. ochroleuca was significantly lower, a mean of 0.62 species per cm3, when compared to the northern species, L. digitata which had a mean of 1.13 species per cm3. Laminaria digitata also had more unique epibiont species indicating that species richness of holdfast assemblages is likely to decline if L. digitata is replaced by L. ochroleuca. These data illustrate the importance of studying biologically generated habitats when considering the potential consequences of climate change on marine assemblages.

In 2002, a jellyfish bloom occurred throughout the Gulf of Oman and the Persian Gulf causing decreased catch in artisanal and industrial fisheries, damage to fishing gear, interrupted operation of desalination plants, and damage to the seawater cooling systems of coastal power plants. The cause and source of the bloom and the species of medusa were unknown. Here, the temporal and spatial distribution of the medusa are described using data from incidental catches in Iranian fisheries surveys, and morphological and molecular evidence are used to identify the medusa as Crambionella orsini (Vanhöffen). This species is endemic to the western Indian Ocean and adjacent basins which dismisses species introduction as the cause of this bloom. Furthermore, because the bloom was geographically widespread, it probably was not caused by local coastal degradation. Although human activities with large-scale effects cannot be ruled out, large-scale oceanographic or ecosystem conditions, perhaps part of natural climate cycles, that yielded moderate sea surface temperatures (in terms of the annual mean monthly anomaly for each year since 1982) were the most likely causes of the bloom of this endemic jellyfish.

Four species of foraminifers Rosalina globularis, Lobatula lobatula, Acervulina inhaerens and Miniacina miniacea were observed as epibionts on some species of the athecate hydroids of the genus Eudendrium—E. armatum, E. glomeratum, E. moulouyensis and E. racemosum—from the Mediterranean Sea. The abundance and the distribution of the protozoans were determined for each hydroid and considered in relation to the shape and size of the Eudendrium branches. Results revealed differences in the composition of the epibiontic assemblage among different species of Eudendrium which were dependent on several factors, but were mainly related to the habitat and to the morphology of the host.

The interactions between Eudendrium and its epibionts were considered to emphasize the role of the Eudendrium colonies as a hotspot not only of poorly known species but also of co-evolutionary relationships and life histories.

Eight species of polydorid polychaetes were found to inhabit mollusc shells from south-western Australian waters. Numerous individuals of Polydora uncinata were extracted for the first time from the shells of both land-based cultured abalone Haliotis laevigata and H. roei, as well as from natural subtidal H. roei and Chlamys australis. Shells of the oyster Saccostrea commercialis cultured in sea-based systems were infested by Boccardia knoxi which was first recorded in these waters. Polydora aura, Dipolydora giardi, D. armata, D. aciculata and Boccardia proboscidea were common among shells of various natural intertidal and subtidal molluscs. A small number of P. haswelli were extracted from their self-excavated burrows in shells of cultured oysters. Boccardia knoxi and D. aciculata were redescribed based on the newly collected materials. Polydora uncinata and B. knoxi exhibited similar larval development patterns (exolecithotrophy and adelphophagy), iteroparity and longer life span, suggesting a high reproductive potential. This study suggests that further monitoring of polydorid species is needed not only from the viewpoint of marine biology but also to survey the risk invasive species pose to commercially important molluscs in this region and worldwide.

In a series of studies on eunicids, there were explicit or implicit indications that Eunice riojai described from the north-western Caribbean Sea, and Eunice sebastiani described from south-east Brazil, were synonyms. This was based upon a then recent monograph on the genus, and on the fact that some specimens were found in drifting wood which would explain the large geographical range. The study of some large specimens of E. sebastiani, collected at the type locality, shows that there are several relevant morphological differences between the two species and thus both species names must be regarded as distinct. In fact, E. sebastiani is unique in the genus because their maxillae V are bidentate. Furthermore, herein we re-describe these two species and re-evaluate some morphological features described in previous studies.

Amphinomida is an ‘isolated’ clade within the polychaete group Aciculata and traditionally includes the families Amphinomidae, Archinomidae and Euphrosinidae. Archinomidae were erected for a single species, the hydrothermal vent polychaete Archinome rosacea. Originally, A. rosacea was assigned to Euphrosinidae although it shares more morphological similarities with Amphinomidae. In this study we assess the position of Archinome, Euphrosinidae and Amphinomidae by using molecular data from nuclear 18S rDNA and 28S rDNA. Parsimony, maximum likelihood and Bayesian analyses are performed on the nucleotide datasets covering in total 19 terminals from Amphinomidae, Euphrosinidae, Archinomidae and outgroups. Our results conclusively show that Euphrosinidae and Amphinomidae are sister taxa and that Archinome is sister to Chloeia within Amphinomidae. Based on these results the family name Archinomidae is treated as a junior synonym of Amphinomidae.

The spatial diversity of meiofauna from sea grass beds of Pujada Bay (the Philippines), was studied with special emphasis on harpacticoid copepods. Sediment cores were obtained from areas adjacent to the different species of sea grasses. Meiofauna was enumerated at higher taxon level and harpacticoid copepods were identified to genus level. Diversity indices were calculated corresponding to the hierarchical levels of spatial biodiversity, i.e. alpha, beta and gamma. Nematodes were the most abundant meiofaunal group in all sediment layers and along the entire tidal gradient (37–92%); harpacticoids were second in abundance (3.0–40.6%) but highly diverse (N0: 9.33–15.5) at the uppermost sediment layer (0–1 cm) near all beds of sea grass species. There was a sharp turnover of harpacticoid genera along the tidal gradient, thus suggesting a relatively low proportion of shared genera among benthic communities in different sea grass zones. The families of Tetragonicipitidae and Miraciidae were the dominant harpacticoid groups occurring in all sediment layers of all sea grass species. The presence of the epiphytic genera of Metis at the deepest sediment layers in some sea grass species was striking. Overall, the major contributor to gamma (total) diversity of harpacticoid copepods in Pujada Bay is the high local (alpha) diversity (N0: 80.6%, H′: 94.7% of total diversity); hence, the habitat heterogeneity among sediment layers in sea grass beds is most relevant for the total diversity and richness of harpacticoid copepod genera in the area.

Monstrilloid copepods from a series of zooplankton samples collected in the coastal area of Miami, Florida, were examined taxonomically. Several adult females were found to belong to an undescribed species of Cymbasoma within the C. rigidum species complex. It can be distinguished from its congeners by the body proportions, shape of head, cephalic ornamentation pattern, genital double somite with straight lateral margins, and structure of the fifth legs, which have a small, inner lobe arising from the distal 1/5 of segment. This species shows intraspecific variability in some characters (i.e. shape of head, cephalic and genital ornamentation patterns); hitherto, such variation has been reported only in another species of Cymbasoma. Our finding supports the idea of the nominal species C. rigidum comprising a taxonomic complex with several undescribed taxa. The other species recorded in the area was Cymbasoma quadridens Davis, 1947. This was first described from a single male specimen collected in 1947 in Biscayne Bay, Florida, and has not been recorded thereafter. The type specimen now being unusable, this species is redescribed herein based on another topotypic male specimen collected near the type locality. New data are added about the armature of its antennules and swimming legs, cuticular ornamentation, and structure of the genital complex.

The success of planktonic copepods in aquatic environments is dependent on efficient sensing of their three-dimensional surroundings. The detection of external cues is of importance for the localization of other organisms (prey, predators and mates), and is mediated by an array of mechano- and chemoreceptors located on the paired antennules (A1).

We investigated the morphology and distribution pattern of A1 sensory structures in the adult female of Clausocalanus furcatus (Copepoda: Calanoida) using different techniques (camera lucida, scanning and transmission electron microscopy and laser scanning confocal microscopy) each focusing on a specific aspect of the structures analysed. Integration of the information collected shows that C. furcatus possesses an array of mechanical, chemical and dual-function sensors over its A1, by which the copepod can detect different stimuli from the environment. Results are discussed in the light of the unique swimming behaviour displayed by this widespread epipelagic copepod.

The taxonomy of the snapping shrimp Alpheus cristulifrons Rathbun, 1900, previously reported from the eastern Pacific and western and eastern Atlantic, is reviewed based on molecular data (COI), morphology and colour patterns. Three species are recognized in the A. cristulifrons species complex. Alpheus cristulifrons sensu stricto is restricted to the western Atlantic, ranging from Florida and the Caribbean Sea to southern Brazil. The eastern Pacific A. cristulifrons sensu Kim & Abele, 1988 corresponds to A. utriensis Ramos & Von Prahl, 1989, ranging from the Gulf of California to Colombia; this species can be separated from A. cristulifrons by the absence of balaeniceps setae on the male minor chela and the presence of bands on the antennular and antennal flagella. The eastern Atlantic A. cristulifronssensu Crosnier & Forest, 1966 is described as A. xanthocarpus sp. nov. based on recently collected material from the island of São Tomé in the Gulf of Guinea; this species differs from A. cristulifrons by the posteriorly more extending rostral carina and the presence of conspicuous yellow spots on the carpus and chela of the second pereiopod. Molecular data suggest that A. utriensis is the eastern Pacific sister clade to the amphi-Atlntic clade that includes A. cristulifrons and A. xanthocarpus sp. nov.

Field observations of small (<20 mm) individuals of Mytulus galloprovincialis at Littlehampton (West Sussex) on the south-eastern coast of England showed that many collected as recently dead shells had a distinctive pattern of damage around the posterior valve margins. Laboratory experiments confirmed that small Carcinus maenas (<22 mm carapace width) were capable of inflicting a similar style of damage. Small C. maenas fed successfully on a range of mussel sizes (5–20 mm shell length), positively correlated with carapace width. All used the same technique to access the bivalve prey, that is, by marginal mandibular chipping in order to achieve sufficient damage to allow insertion of a chelal dactyl between the valves. Mandibular chipping has previously been reported upon from non-chelate decapods and juvenile lobsters. The chelae of juvenile C. maenas are small and have a lower mechanical advantage than has been reported upon for adult conspecifics which, in any case, are not highly adapted for durophagy. We suggest that because of the poor mechanical performance and small gape of the chelae juvenile C. maenas behave as though they were achelate. As well as broadening our understanding of the repertoire of known feeding behaviours of C. maenas, our study may also provide an insight into the evolution of durophagy within the Decapoda.

The relative growth of the fiddler crab Uca cumulanta was studied, primarily to determine the size at the onset of sexual maturity for a mangrove population in the estuary of the Patitiba River, Paraty, Rio de Janeiro state, Brazil. The evaluation of the morphological sexual maturity of U. cumulanta was performed using the allometric technique. The relationships that most precisely indicated the size at onset of sexual maturity were carapace length (CL) vs propodus length for males and CL vs abdomen width for females. Males and females are mature at 5.25 and 4.75 mm CL, respectively. The remarkable ontogenetic changes observed in the allometric growth of the male major cheliped and the female abdomen, indicate that growth of these structures is closely connected to the timing of sexual maturity. The relative size at onset maturity obtained for this species was 0.68 and this index was compared to that seen in other species in the genus.

The ecdysteroids ecdysone (E), 20-hydroxyecdysone (20E) and ponasterone A (PoA) were measured in the haemolymph, hepatopancreas and oocytes of female shore crabs Carcinus maenas during the moulting cycle and during oocyte maturation using HPLC-MS. In the haemolymph, ecdysteroid titres varied over the moulting cycle with high levels during premoult and low levels during postmoult and intermoult, however, no significant change in haemolymph ecdysteroid titres was observed in relation to oocyte development. In the hepatopancreas, PoA levels were high during premoult but low during postmoult and intermoult. This is in contrast to E and 20E where levels remained high from early intermoult (C1) until late premoult (D3) and only decreased during postmoult. In the oocytes, ecdysteroid levels were low during postmoult and for 20E and PoA also during late premoult D2 and D3. In contrast, all three ecdysteroids were observed to increase in the oocytes during oocyte development, in particular E and PoA. The present study demonstrates that changes in haemolymph ecdysteroid titres relate to changes in moulting status and not to changes in oocyte development. Also, the study indicates that the hepatopancreas is involved in the metabolism of ecdysteroids related to the moulting cycle but may also be involved in ecdysteroid metabolism during oocyte development. Furthermore, the pronounced increase in oocyte ecdysteroids during oocyte development during periods where haemolymph ecdysteroids titre is low, indicates that the oocytes are capable of de novo synthesis of the three ecdysteroids investigated.

The annual commercial catch from the Southern Zone of the South Australian rock lobster (Jasus edwardsii) fishery is ~1900 tonnes, representing ~50% of total landings from south-east Australia. A single minimum legal size (MLS) of 98.5 mm carapace length (CL) exists across the entire zone. Fecundity (F), size at onset of maturity (SOM) and relative reproductive potential (RRP) of female rock lobsters were investigated in two major fishing regions, i.e. the North Southern Zone (NSZ) and South Southern Zone (SSZ) with a view to providing a basis for future fine-scale spatial management of the resource. F ranged from 45,292 to 466,800 eggs per female and increased proportionally with CL according to the relationship: F = 0.0584 × CL3.1642. F was significantly higher in the NSZ compared to the SSZ but was attributed to differences in lobster size between regions. There was no significant difference in the number of eggs · g−1 of egg mass between areas. SOM, estimated as the size at which 50% of females reached sexual maturity (L50) was higher in the NSZ (104.1 mm CL) compared to SSZ (92.3 mm CL). Approximately 20% of lobsters above the MLS in the commercial catch in the NSZ were under the L50 estimate. RRP, as a measure of egg production, was calculated for each size-class from the product of F, SOM and population length–frequency. The modal RRP size-classes in the NSZ were 117.5–122.5 mm CL, while in the SSZ it was 97.5–102.5 mm CL. Only 6% of RRP was contributed by female rock lobsters below the MLS in the NSZ, compared to 34% in the SSZ. Regional differences in SOM and RRP in the Southern Zone of South Australia suggest that different MLSs may be beneficial, particularly if the fishery is to be effectively managed at finer spatial scales.

The tanaidaceans are among the most conspicuous and ecologically relevant benthic microcrustaceans in the marine realm but there are only a few records of species of tanaids associated with other marine organisms. During a long-term survey on the biology and distribution of the Caribbean manatee Trichechus manatus manatus Linnaeus in Mexican waters, parasites and epibionts were collected from 47 individuals that were captured for tagging in two bay systems. Well-established epibiotic communities of the tanaidacean Hexapleomera robusta (Moore) were found on eight of these animals; this tanaid crustacean formed patches of tubes adhered to the skin surface. Patches were distributed in different parts of the body surface but mainly along the backbone depression, the caudal zone, and on the lateral margins; in some instances they were related to clusters of barnacles. Highly significant differences of infestation rates were revealed between Chetumal Bay and Ascensión Bay, the latter representing better conditions (high salinity and hydrodynamism) for tanaid invasion and settlement on the manatee. It is speculated that the tanaid is a commensal; no visible damage was found in the host and its presence was not related to skin lesions. The tanaid probably captures suspended particles as the manatee feeds. This is the first confirmed record of a symbiotic association involving a tanaid and the Caribbean manatee. The tanaid species recorded (H. robusta) and the harpacticoid copepod Balaenophilus manatorum (Ortíz, Lalana & Torres), have both been recorded also as epibionts of sea turtles. The tanaid has been known from sea turtles for some time, but the copepod was first recorded from a manatee and was subsequently found on sea turtles a few years later.

A cold-shock technique was used to determine radula production rates for the chitons Acanthopleura hirtosa and Plaxiphora albida, and for the limpet Patelloida alticostata, which replaced their radular teeth at rates of 0.40, 0.36 and 0.51 rows d−1, respectively. These rates are far slower than those determined previously for non-iron-mineralizing molluscs, suggesting that the improved working life of the teeth afforded by iron-mineralization acts to significantly reduce replacement rates. In addition, inductively coupled plasma-atomic emission spectroscopy has been used to determine the quantity of iron and other elements comprising the radula of each species. These data, used in conjunction with the radula production rates, reveal that A. hirtosa, Plaxiphora albida and Patelloida alticostata have daily radula mineralization requirements for iron of 3.06, 4.12 and 0.55 μg, respectively. Such information is vital for continuing studies related to the cellular delivery of ions and subsequent biomineralization of the tooth cusps in chitons and limpets.