Inspection videos of four offshore platforms in the central and northern North Sea were used to study the development of fouling communities on clamps and guides of oil export risers over an 11-y period (1989–2000). Results from multivariate analyses (multi-dimensional scaling and analysis of similarities) indicated that distinct assemblages developed in different geographical locations. These differences were mainly due to the protracted development of the Metridium senile (Cnidaria: Actinaria) zone on the northern sector platforms. The vertical zonation of fouling organisms was similar on all installations, although the water depth at platform locations varied from 80 to 169 m, indicating that fouling organisms display a wide bathymetric tolerance. This study has highlighted the value of long-term data present in operational inspection videos for the study of fouling communities.

Oncholaimus cobbi was described from the Brazilian coast. The area studied, Coroa Grande, is located in Sepetiba Bay, State of Rio de Janeiro, Brazil. Sampling was carried out monthly, from May 1998 through April 1999. Most of the population was represented by adults, of which non-ovigerous females were the most abundant category. The species reached its highest population density during the warmest months, and the highest densities of males and ovigerous females were seen in February 1999.

Third-stage larval and adult infrapopulations of the whaleworm Anisakis simplex sensu lato (s.l.) (Nematoda: Anisakidae) from their respective fish, cephalopod and cetacean hosts caught or stranded in the Galician coast (north-west Spain), were analysed for heavy metals by atomic absorption spectrometry. Results suggest that the whaleworm may accumulate lead and copper to levels far in excess of their host tissues.

This review discusses the structure and operation of the fine mesh ‘mucous’ feeding filters of tunicates. The function of the endostyle in producing the feeding filter and the different ways in which the filter is deployed are also described.

The fine structure of the filter includes new data, and the ultrastructural dimensions of the filter mesh and filament thickness are tabulated for the different tunicate groups. Histochemical data suggest that a peptide core is surrounded by a mucopolysaccharide sheath, and endostyle gland cell histochemistry and ultrastructure indicates protein synthesis. The construction of the filter by the endostyle was first considered in ascidians, and has been updated by observations on the simpler endostyle in salps, where there is evidence that secretions of gland cells pass to the bases of a fence of cilia, there to fuse and pass off the ciliary tips as fine filaments composing the filter net. Although all filters that have been examined when deployed have a rectangular mesh, reasons are given for supposing that when formed in the endostyle they have a square mesh in which both longitudinal and transverse filaments are of similar thickness and that the transverse filaments are stretched as the filter is deployed, so becoming thinner.

Finally, some ecological consequences of the filter parameters in the different tunicate groups are considered.

Changes in the intracellular free amino acid (FAA) concentrations of Tigriopus brevicornis when subjected to hypoosmotic (5 psu), normal seawater (35 psu) and hyperosmotic (70 psu) conditions for a three day acclimation period were investigated. Proline, alanine and lysine were the major contributors to the intracellular FAA pool. Under hypoosmotic conditions, alanine was the dominant osmolyte with proline concentration at its lowest. This trend was reversed under hyperosmotic conditions. However, the total FAA pool was at its highest concentration under normal seawater conditions, with the total FAA concentrations being reduced during hypo- and hyper-osmotic conditions.

In April 2000 a massive recruitment of the barnacle Semibalanus balanoides was observed in the Clyde Sea. At one location 700 cyprids 1−1 of this species were recorded. This is ∼3500 times more abundant than previously recorded, and resulted in metamorphosis of some cyprids whilst still in the plankton, as well as massive settlement, with recruits found on adults and in the splash zone. The maximum density recorded was 109 settlers cm−2. Over the next 60 d mortality averaged 85%, resulting in a mean density of 8.4 recruits cm−2 in June 2000. Recruitment varied spatially at the km and m scale (site, shore height) but there was no evidence that it was affected by the presence of adult conspecifics.

An ecologically unique cirripede, Octolasmis unguisiformis sp. nov. (Cirripedeia: Thoracica: Poecilasmatidae), was found to be ectosymbiotic with an ocypodid crab, Macrophthalmus milloti, on tidal flats of the Amami Islands, the Ryukyu Archipelago, Japan. The cirripedes were attached to the ventral side of the crab carapace, around the bases of the first and second ambulatory legs. The cirripedes resemble the chelipeds of male host crabs. Adult cirripedes were found only on female crabs, whereas juvenile cirripedes were present on crabs of both sexes, suggesting that the survival rate of the cirripedes on female crabs was higher than that of those on male crabs. The cheliped-like appearance and female-biased distribution of the cirripedes are discussed from the standpoint of mutualism between the crab and the epizoic cirripede.

Kalliapseudes schubartii (Crustacea: Tanaidacea) is a tube dwelling invertebrate living in estuarine soft bottoms with distribution along the south-east and southern Brazilian and Uruguayan coasts. Individual growth, and reproduction were examined by taking samples for a year in the estuarine region of the Lagoa dos Patos (southern Brazil). The von Bertalanffy model described growth of K. schubartii (K=4.54 y−1, L∞=13.22 mm). Reproductive activity was observed in spring and summer. No relationship was observed between total length of females and brood size. Eggs, embryos, and mancas were often observed in a marsupium. Relative growth analysis showed two levels of allometry in the growth of chelipeds of males.

The fecundity and occurrence of intersexuality in the amphipod, Echinogammarus marinus, collected from populations on the east coast of Scotland are reported. Intersex specimens have significantly smaller mean brood sizes than normal specimens. Embryo survival, as measured by the ratio of eggs/embryos in early and late stages of development, is lower in intersex specimens than normal specimens. Greater differences in the number of early stage eggs compared with late stage eggs in intersex specimens is suggested to arise by the active ejection of non-viable eggs, or from the passive loss of eggs through malformed brood plates in females. An apparent reduction in brood sizes between early and late stages of development in ‘normal’ specimens, emphasizes the importance of quantifying different egg/embryo stages in amphipod toxicology and fecundity studies.

Evidence of female preference for dominant males during mating is reported for the rock shrimp Rhynchocinetes typus. Two sexually mature males of different ontogenetic stage were tethered at opposite sides of a large tank. Tethering restricted males from actively pursuing the receptive female but allowed females to choose between males. Surprisingly most (10 out of 11) females first approached the subordinate typus male, but after these initial contacts all females chose the dominant robustus male. Following antennal and corporal contacts of variable duration seven (out of 11) females initiated the mating process with the robustus male, while four females did not initiate mating during the 90 min observation period. The fact that all mating females selected the robustus shows strong female preferences for these males. It is suggested that female preference for large and dominant males is common among crustaceans with sexual size-dimorphism.

Caprellid amphipods, Caprella danilevskii were exposed to tributyltin (TBT) (100 ng 1−1) for ten periods after eggs were deposited in the brood pouch. Brood loss during incubation was found in six exposure periods between 12 and 72 h after spawning, although no brood loss was observed in the control. It was suggested that exposure to TBT half a day after spawning might be sufficient to damage reproduction during the caprellid's embryonic life. The female percentage was 38.7% in the control, whereas it was gradually increased to 60.0–71.4% in the four exposure periods between 12 and 48 h after spawning.

The subunit composition of haemocyanin (Hc) from the semiterrestrial beachflea Orchestia gammarellus exhibited less heterogeneity and less (qualitative) between-individual variation than most decapod Hcs. While between-population variation was detected, no clear trends in Hc subunit composition from four populations along a salinity gradient were observed. Salinity had no detectable effect on Hc subunit composition or HcO2 binding in the laboratory. The degree of phenotypic variation in laboratory-held beachfleas was less than that displayed by any of the natural populations examined. Furthermore, examination of the O2 binding characteristics of five of the most common Hc phenotypes showed that each phenotype had the same O2 binding properties. Differences in Hc subunit composition between individuals and between populations may exist, but it should not be automatically assumed that such variation will have consequences for intrinsic Hc O2 binding properties.

The variability of larval morphology in the caridean shrimp Nauticaris magellanica cultivated in the laboratory was analysed, and its applicability for the identification of larval stages collected from the plankton evaluated. Both morphometric and meristic variability of selected appendages was analysed comparing larvae from the rearing experiment with those obtained from the plankton. Larval development in the laboratory consisted of at least nine zoeal and five decapodid stages, followed by the first juvenile stage. Larvae collected from the plankton, comprising individuals from zoea II to, presumably, zoea VIII, were generally more developed and had a larger size than the corresponding stages reared in the laboratory. Cultured larvae showed a high exophenotypical variability starting with zoea IV, which impeded an immediate determination of larval stages obtained from the plankton.

The Monaco shrimp Lysmata seticaudata is a warm temperate species with strong potential for the marine aquarium industry and knowledge on embryo production and brood loss during incubation is essential for the establishment of proper maturation techniques. Average (±SD) brood size of small (total length (TL) 40–44 mm), medium (TL 48–52 mm) and large (TL 58–62 mm) simultaneous hermaphroditic (SH) phase were 753 (±215), 1351 (±163) and 1810 (±264) newly extruded embryos, respectively, in early reproductive season (ERS); and 745 (±258), 1314 (±191) and 1813 (±219), respectively, in late reproductive season (LRS). Senescence does not seem to occur in the Monaco shrimp, since during both ERS and LRS larger SH shrimp always presented a higher number of embryos and negative allometry was not recorded. No significant differences in brood size were recorded among broods at different embryonic stages of shrimp in the same size-class in both ERS and LRS. Brood losses recorded from embryonic Stage 1 to Stage 4 for small, medium and large shrimp were 14.3%, 11.3% and 8.9%, respectively, for ERS and 10.9%, 14.4% and 12.2%, respectively, for LRS. The mean embryo volume in the same development stage was not significantly different among the small, medium and large shrimp, and between ERS and LRS for shrimp of same size-class. For all shrimp size-classes during both ERS and LRS, mean embryo volume significantly increased from 108.5% to 127.9%, from first to last embryonic stage. The occurrence of sex change does not affect egg production since small females in ERS (before the major period of sex change) and LRS (after the major period of sex change) had similar brood sizes.

Biochemical changes during the reproductive cycle of Aristeus antennatus (Crustacea: Decapoda) on the Portuguese south coast were investigated. Proximate chemical composition, lipid classes, fatty acid profiles, glycogen and cholesterol content were determined in the muscle, ovary and hepatopancreas (HP) during a period of one year (October 2000–September 2001). Gonadosomatic index (GSI) increased significantly in June and July and during the maturation process. Hepatosomatic index (HSI) also increased throughout the ovarian maturation. A positive correlation between lipid levels in the ovary and GSI (r=0.53, P<0.05) and HSI (r=0.30, P<0.05) was found. The muscle showed very low lipid levels and higher percentages of polar lipids. Higher proportions of neutral lipids, mainly triacylglycerols, were observed in both ovary and HP. Both ovarian and HP cholesterol increased with maturation. Protein and glycogen content in the muscle, ovary and HP did not vary as a function of ovary maturity stage. From the different tissues analysed, the glycogen is mainly stored in the HP and to a lesser extent in the muscle. In both ovary and HP the major fatty acids were 16:0, 18:1(n-7), 18:1(n-9), 20:5(n-3) and 22:6(n-3), and significant increase in the levels of monounsaturated fatty acids were observed in ovary during sexual maturation, which indicates these compounds as the major sources of energy during embryonic and early larval development.

Portunus pelagicus (Crustacea: Portunidae) was collected monthly for a minimum of two years from two marine embayments (Cockburn Sound and Koombana Bay) and two estuaries (Peel-Harvey and Leschenault) that are located between 32° and 33°S on the lower west coast of Australia. A birth date of 1 December, derived from estimates of the peak time of spawning, was used to determine the average age of crabs in the main size cohort(s) in carapace width–frequency histograms for each month in each water body. The resultant carapace width-at-age data for each sex in Cockburn Sound and the Peel-Harvey Estuary, in which recruitment occurs at an early age, were then described using a seasonal von Bertalanffy growth curve. The results demonstrated that the growth rates of P. pelagicus differed significantly neither between females and males nor between crabs in the two water bodies and that growth was highly seasonal, with little or no increase in size occurring during the cold winter and early spring months. They also showed that relatively few P. pelagicus live beyond 18 months and indicate that, as a result of legal restrictions against retaining ovigerous crabs and the poor quality of recently-moulted females, fishing mortality is far lower amongst female than male crabs. The fact that the carapace widths attained by P. pelagicus at the end of its first year of life in Cockburn Sound (105 mm) and the Peel-Harvey Estuary (109 mm) were very similar to those in the Leschenault Estuary (105 mm) and Koombana Bay (107 mm) into which that estuary discharges emphasizes that the growth of P. pelagicus in each of these systems was similar. Data are also presented which strongly indicate that the second moult undergone by mature females is accompanied by an increase in the relative size of the abdominal flap.

The arrow crab Stenorhynchus seticornis (Brachyura, Majidae), is a common inhabitant of the rocky subtidal along the Brazilian coast. Fecundity and the influence of environmental variables on egg production are investigated in this study. Information on egg size and egg loss through incubation are also provided. Monthly samples were conducted using SCUBA diving, from January to December 1998 in the Ubatuba region (23°25′25[double prime or second]S–44°52′03[double prime or second]W), south-eastern Brazilian coast. Early broods were used for the estimation of size-specific relationships of fecundity. Egg loss was assessed by comparing average egg numbers of early and late broods. The fecundity was estimated in 621.1±339.6 eggs, with an average diameter of 0.48±0.1 and 0.57±0.1 mm for early and late eggs, respectively. The number of eggs produced was apparently constant year-round. No significant differences were recorded among monthly fecundity values. The variation of abiotic factors did not show any relationship with temporal variability of fecundity, suggesting that the environmental effect in egg production is slight at best.

Excavation counts (absolute density), burrow counts and surface active individuals visual counts in a Uca tangeri population were compared. Population density estimated from burrow counts was not significantly different from population density estimated by excavation, but the population density estimated with visual counts was significantly lower than the absolute density. Ovigerous females should be the main cause of these differences because they frequently remain underground, but other groups of crabs are also contributing to this difference. Burrow counting is an accurate and quick non-invasive method for the census of U. tangeri. Other population measures (e.g. sex ratio) are not obtainable by burrow counting and only further understanding of the activity patterns of this species along the tide cycle, moon phase and reproductive season will allow visual counting of surface active individuals to be used as quick, efficient and non-invasive method for crab density and population structure estimation.

The proportion of berried (externally egg-bearing) females, fecundity, gonadosomatic index, and egg size of the blue swimmer crab Portunus pelagicus off southern Australia were examined by analysing data from samples of commercial catches using generalized linear models. Ovarian development was studied morphologically and histologically. Female blue swimmer crabs spawn from October to January and can spawn more than once per season. The fecundity of female blue swimmer crabs initially increased with carapace width, maximized at a carapace width of 134 mm, and decreased thereafter. Thus, fecundity increased 83.9% with an increase of carapace width from 105 to 125 mm, implying a single large female can produce as many eggs as two or more small females. The gonadosomatic index of female crabs from Spencer Gulf increased 2.4% from October 1998 to November 1998, increased an additional 15.9% by December 1998, and then decreased 62.3% to its minimum in January 1999. Gonadosomatic index also increased with 1/3 power of their body weight. Thus, the commonly used gonadosomatic index is overly simplistic for blue swimmer crabs. Unlike tropical or subtropical female blue swimmer crabs which often continually spawn, those off southern Australia spawn only in certain times of the year. The implications of this work lead to suggestions for three management measures for the commercial fishery: maintaining the prohibition of catching berried females, extending the seasonal closure from October to January, and maintaining the current legal minimum carapace width of 110 mm.

Over the course of the moult cycle of Maja squinado, the spider crab changes in the hardness and colour of the carapace were assessed and used as methods to identify the intermoult stage in each individual. This intermoult staging was later verified by means of the microscopic observation of the maxilla. These staging techniques made it possible for the prompt identification of the principal intermoult stages—postmoult, intermoult and premoult. In 90% of the cases analysed, there was a correlation between the presence of an underlying carapace and a pink colour of the abdominal vein in crabs in advanced premoult stages.

The seasonality of the moult was studied based on the number of specimens in the postmoult stage. There were two main moulting periods—the first occurring in April, and the second, longer period was between July and November. A hypothetical growth model was established and growth rates were determined by length–frequency distribution analyses. Three groups of juveniles and one group of adults were identified. The adults were only found among the population between July and October. In both males and females, the moult increment rate was lower in terminal moults (mean=22%) than in juvenile or prepubertal moults (mean=27%).